From 8e4f77bd9f6f8327b2541cf74f05d0ed23e95b78 Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Tue, 2 Nov 2021 09:51:10 +0100
Subject: [PATCH 01/21] feat(bulb): add bulb, an OS that solely relies on
 mailbox comms

---
 Makefile                                  |  19 +-
 bulb/Makefile                             | 124 +++++++++++
 bulb/include/common/debug.h               |  16 ++
 bulb/include/common/font.h                |  36 ++++
 bulb/include/common/gpu.h                 |  57 +++++
 bulb/include/common/logging.h             |  27 +++
 bulb/include/common/printf.h              | 107 ++++++++++
 bulb/include/common/screen.h              |  20 ++
 bulb/include/common/status_led.h          |  24 +++
 bulb/include/common/stdbool.h             |  10 +
 bulb/include/common/stddef.h              |  10 +
 bulb/include/common/utils.h               |  12 ++
 bulb/include/kernel/arm/sysregs.h         |  49 +++++
 bulb/include/kernel/entry.h               |  35 ++++
 bulb/include/kernel/mailbox.h             |  40 ++++
 bulb/include/kernel/mm.h                  |  33 +++
 bulb/include/kernel/mmu.h                 |  38 ++++
 bulb/include/kernel/peripherals/base.h    |   6 +
 bulb/include/kernel/peripherals/gpio.h    |  12 ++
 bulb/include/kernel/peripherals/gpu.h     |  10 +
 bulb/include/kernel/peripherals/mailbox.h |  19 ++
 bulb/src/common/debug.c                   |  29 +++
 bulb/src/common/font.c                    | 195 +++++++++++++++++
 bulb/src/common/gpu.c                     | 137 ++++++++++++
 bulb/src/common/printf.c                  | 243 ++++++++++++++++++++++
 bulb/src/common/screen.c                  |  14 ++
 bulb/src/common/status_led.c              |  55 +++++
 bulb/src/common/utils.S                   |  21 ++
 bulb/src/config.txt                       |   2 +
 bulb/src/kernel/boot.S                    |  52 +++++
 bulb/src/kernel/kernel.c                  |  43 ++++
 bulb/src/kernel/mailbox.c                 |  52 +++++
 bulb/src/kernel/mm.S                      |  14 ++
 bulb/src/kernel/mm.c                      |  19 ++
 bulb/src/kernel/mmu.c                     | 134 ++++++++++++
 bulb/src/linker.ld                        |  19 ++
 36 files changed, 1730 insertions(+), 3 deletions(-)
 create mode 100644 bulb/Makefile
 create mode 100644 bulb/include/common/debug.h
 create mode 100644 bulb/include/common/font.h
 create mode 100644 bulb/include/common/gpu.h
 create mode 100644 bulb/include/common/logging.h
 create mode 100644 bulb/include/common/printf.h
 create mode 100644 bulb/include/common/screen.h
 create mode 100644 bulb/include/common/status_led.h
 create mode 100644 bulb/include/common/stdbool.h
 create mode 100644 bulb/include/common/stddef.h
 create mode 100644 bulb/include/common/utils.h
 create mode 100644 bulb/include/kernel/arm/sysregs.h
 create mode 100644 bulb/include/kernel/entry.h
 create mode 100644 bulb/include/kernel/mailbox.h
 create mode 100644 bulb/include/kernel/mm.h
 create mode 100644 bulb/include/kernel/mmu.h
 create mode 100644 bulb/include/kernel/peripherals/base.h
 create mode 100644 bulb/include/kernel/peripherals/gpio.h
 create mode 100644 bulb/include/kernel/peripherals/gpu.h
 create mode 100644 bulb/include/kernel/peripherals/mailbox.h
 create mode 100644 bulb/src/common/debug.c
 create mode 100644 bulb/src/common/font.c
 create mode 100644 bulb/src/common/gpu.c
 create mode 100644 bulb/src/common/printf.c
 create mode 100644 bulb/src/common/screen.c
 create mode 100644 bulb/src/common/status_led.c
 create mode 100644 bulb/src/common/utils.S
 create mode 100644 bulb/src/config.txt
 create mode 100644 bulb/src/kernel/boot.S
 create mode 100644 bulb/src/kernel/kernel.c
 create mode 100644 bulb/src/kernel/mailbox.c
 create mode 100644 bulb/src/kernel/mm.S
 create mode 100644 bulb/src/kernel/mm.c
 create mode 100644 bulb/src/kernel/mmu.c
 create mode 100644 bulb/src/linker.ld

diff --git a/Makefile b/Makefile
index 09b3a90..1ee03d7 100644
--- a/Makefile
+++ b/Makefile
@@ -12,7 +12,7 @@ MNT_Darwin = /Volumes/boot
 #BOOT_PART = /dev/mmcblk0p1
 
 # Serial connection config
-SEND_DEFAULT_TARGET = thorn
+SEND_DEFAULT_TARGET = bulb
 BAUD_RATE = 115200
 SERIAL_PORT = $(SERIAL_PORT_$(HOST_OS))
 SERIAL_PORT_ALT = $(SERIAL_PORT_ALT_$(HOST_OS))
@@ -22,7 +22,7 @@ SERIAL_PORT_Darwin     = /dev/$(shell ls /dev | grep usbserial | head -n 2 | tai
 SERIAL_PORT_ALT_Darwin = /dev/$(shell ls /dev | grep usbserial | head -n 1)
 
 # Building
-BUILD_DEFAULT_TARGET = thorn
+BUILD_DEFAULT_TARGET = bulb
 
 # Ensure make still works if someone creates a file named like follows:
 .PHONY: all build clean flash resend send reboot poweroff
@@ -35,11 +35,12 @@ clean:
 	rm -rf $(BUILD) *.img
 	$(MAKE) -C chainloader clean
 	$(MAKE) -C thorn clean
+	$(MAKE) -C bulb clean
 
 # Build the different OSes
 build: build-$(BUILD_DEFAULT_TARGET)
 
-buildall: build-chainloader build-thorn
+buildall: build-chainloader build-thorn build-bulb
 
 build-chainloader:
 	$(MAKE) -C chainloader build
@@ -47,6 +48,9 @@ build-chainloader:
 build-thorn:
 	$(MAKE) -C thorn build
 
+build-bulb:
+	$(MAKE) -C bulb build
+
 # Mount boot partition of SD card onto set mount point to copy image onto it
 flash: flash-$(FLASH_DEFAULT_TARGET)
 
@@ -56,6 +60,9 @@ flash-chainloader:
 flash-thorn:
 	$(MAKE) -C thorn flash
 
+flash-bulb:
+	$(MAKE) -C bulb flash
+
 # Send kernel size + kernel
 setup-serial-Linux:
 	stty -F $(SERIAL_PORT) $(BAUD_RATE) raw cs8 -ixoff -cstopb -parenb
@@ -77,6 +84,9 @@ send-chainloader: setup-serial-$(HOST_OS)
 send-thorn: setup-serial-$(HOST_OS)
 	$(MAKE) -C thorn send
 
+send-bulb: setup-serial-$(HOST_OS)
+	$(MAKE) -C bulb send
+
 # Set up screen on alternate serial port
 screen:
 	screen $(SERIAL_PORT_ALT) $(BAUD_RATE)
@@ -99,3 +109,6 @@ emulate-chainloader:
 emulate-thorn:
 	$(MAKE) -C thorn emulate
 
+emulate-bulb:
+	$(MAKE) -C bulb emulate
+
diff --git a/bulb/Makefile b/bulb/Makefile
new file mode 100644
index 0000000..e510523
--- /dev/null
+++ b/bulb/Makefile
@@ -0,0 +1,124 @@
+# | Makefile for the Rose project (github.com/anarchuser/rose)
+# | Merged from https://jsandler18.github.io/ and https://github.com/s-matyukevich/raspberry-pi-os
+
+# Cross-compiler
+ARMGNU ?= aarch64-none-elf
+
+# Resolve Mac / linux issues
+HOST_OS = $(shell uname -s)
+
+# Build target
+IMAGE_NAME = $(shell basename `pwd`)
+
+# Options for C, Asembly, and the linker, respectively
+COPS   = -Wall -nostdlib -nostartfiles -ffreestanding -Iinclude -mgeneral-regs-only
+ASMOPS = -Iinclude
+LOPS   = -ffreestanding -nostdlib
+
+# Mount point and boot partition
+MNT = $(MNT_$(HOST_OS))
+MNT_Linux  = ../mnt
+MNT_Darwin = /Volumes/boot
+
+# Serial connection config
+BAUD_RATE = 115200
+SERIAL_PORT = $(SERIAL_PORT_$(HOST_OS))
+SERIAL_PORT_Linux      = /dev/$(shell ls /dev | grep ttyUSB    | head -n 2 | tail -n 1)
+SERIAL_PORT_Darwin     = /dev/$(shell ls /dev | grep usbserial | head -n 2 | tail -n 1)
+
+# Directories for built files, source files (kernel and common) and header files (include)
+BUILD   = build
+SRC     = src
+KERNEL  = kernel
+COMMON  = common
+INCLUDE = include
+
+# Assemble lists of corresponding source files for assembly, kernel and common
+SRC_KERNEL = $(wildcard $(SRC)/$(KERNEL)/*.c)
+ASM_KERNEL = $(wildcard $(SRC)/$(KERNEL)/*.S)
+SRC_COMMON = $(wildcard $(SRC)/$(COMMON)/*.c)
+ASM_COMMON = $(wildcard $(SRC)/$(COMMON)/*.S)
+
+# Assemble list of compiled objects, correspondingly
+OBJECTS  = $(patsubst $(SRC)/$(KERNEL)/%.c, $(BUILD)/$(SRC)/$(KERNEL)/%_c.o, $(SRC_KERNEL))
+OBJECTS += $(patsubst $(SRC)/$(KERNEL)/%.S, $(BUILD)/$(SRC)/$(KERNEL)/%_S.o, $(ASM_KERNEL))
+OBJECTS += $(patsubst $(SRC)/$(COMMON)/%.c, $(BUILD)/$(SRC)/$(COMMON)/%_c.o, $(SRC_COMMON))
+OBJECTS += $(patsubst $(SRC)/$(COMMON)/%.S, $(BUILD)/$(SRC)/$(COMMON)/%_S.o, $(ASM_COMMON))
+
+# Ensure make still works if someone creates a file named like follows:
+.PHONY: build clean flash flash-Linux flash-Darwin emulate reboot poweroff send resend
+
+# Default target (invoked by `make` or `make build`).
+build: $(IMAGE_NAME).img
+
+# Build kernel executable and linkable file where we can extract the kernel from
+$(IMAGE_NAME).elf: $(OBJECTS) $(SRC)/linker.ld
+	$(ARMGNU)-ld -T $(SRC)/linker.ld -o $(BUILD)/$(IMAGE_NAME).elf $(OBJECTS)
+
+# Build actual kernel image
+$(IMAGE_NAME).img: $(SRC)/linker.ld $(OBJECTS) $(IMAGE_NAME).elf
+	$(ARMGNU)-objcopy $(BUILD)/$(IMAGE_NAME).elf -O binary $(IMAGE_NAME).img
+
+# All kernel source targets
+$(BUILD)/$(SRC)/$(KERNEL)/%_c.o: $(SRC)/$(KERNEL)/%.c
+	mkdir -p $(@D)
+	$(ARMGNU)-gcc $(COPS) -MMD -c $< -o $@
+
+# All assembly source targets
+$(BUILD)/$(SRC)/$(KERNEL)/%_S.o: $(SRC)/$(KERNEL)/%.S
+	mkdir -p $(@D)
+	$(ARMGNU)-gcc $(ASMOPS) -MMD -c $< -o $@
+
+# All common source targets
+$(BUILD)/$(SRC)/$(COMMON)/%_c.o: $(SRC)/$(COMMON)/%.c
+	mkdir -p $(@D)
+	$(ARMGNU)-gcc $(COPS) -MMD -c $< -o $@
+
+# All assembly source targets
+$(BUILD)/$(SRC)/$(COMMON)/%_S.o: $(SRC)/$(COMMON)/%.S
+	mkdir -p $(@D)
+	$(ARMGNU)-gcc $(ASMOPS) -MMD -c $< -o $@
+
+# Compile lists with the dependencies between objects
+DEP_FILES = $(OBJECTS:%.o=%.d)
+	-include $(DEP_FILES)
+
+# Remove kernel and build directory
+clean:
+	rm -rf $(BUILD) *.img
+
+# Mount boot partition of SD card onto set mount point to copy image onto it
+flash: flash-$(HOST_OS)
+
+flash-Linux: $(IMAGE_NAME).img
+	mkdir -p $(MNT)
+	mount $(MNT)
+	cp $(IMAGE_NAME).img $(MNT)/kernel8.img
+	cp $(SRC)/config.txt $(MNT)
+	sync
+	sleep 1
+	umount $(MNT)
+
+flash-Darwin: $(IMAGE_NAME).img
+	cp $(IMAGE_NAME).img $(MNT)/kernel8.img
+	cp $(SRC)/config.txt $(MNT)
+	sync
+	diskutil unmount $(MNT)
+
+resend: reboot send
+
+send: $(IMAGE_NAME).img
+	printf "0: %.8x" $(shell wc -c < $(IMAGE_NAME).img) | xxd -r -g0 > $(SERIAL_PORT)
+	cat $(IMAGE_NAME).img > $(SERIAL_PORT)
+
+# Run on qemu
+emulate: $(IMAGE_NAME).img
+	qemu-img resize $(IMAGE_NAME).img -f raw 4294967296
+	qemu-system-aarch64 -cpu cortex-a72 -machine type=raspi3 -m 1024 -kernel $(IMAGE_NAME).img -nographic -serial null -chardev stdio,id=uart1 -serial chardev:uart1 -monitor none
+
+poweroff:
+	$(MAKE) -C .. poweroff
+
+reboot:
+	$(MAKE) -C .. reboot
+
diff --git a/bulb/include/common/debug.h b/bulb/include/common/debug.h
new file mode 100644
index 0000000..99e2ec3
--- /dev/null
+++ b/bulb/include/common/debug.h
@@ -0,0 +1,16 @@
+#ifndef _ROSE_C_DEBUG_H
+#define _ROSE_DEBUG_H
+
+#include "common/logging.h"
+#include "common/printf.h"
+#include "common/stddef.h"
+
+#define CHECKPOINT LOG ("Checkpoint");
+
+void print_hex (unsigned char dec);
+
+void hex_dump (byte_t * array);
+
+void int_dump (unsigned int * array);
+
+#endif//_ROSE_C_DEBUG_H
\ No newline at end of file
diff --git a/bulb/include/common/font.h b/bulb/include/common/font.h
new file mode 100644
index 0000000..5b49ada
--- /dev/null
+++ b/bulb/include/common/font.h
@@ -0,0 +1,36 @@
+#ifndef _ROSE_C_FONT_H
+#define _ROSE_C_FONT_H
+
+#define FONT_SIZE       8
+#define FONT_FACTOR     2
+#define FONT_REAL_WIDTH (FONT_SIZE * FONT_FACTOR)
+
+// Spacing between lines in pixels
+#define FONT_SPACING     4
+#define FONT_REAL_HEIGHT (FONT_REAL_WIDTH + FONT_SPACING)
+
+// Width of horizontal tabs in characters
+#define FONT_TAB_SIZE       4
+#define FONT_TAB_REAL_WIDTH (FONT_TAB_SIZE * FONT_REAL_WIDTH)
+
+#include "common/gpu.h"
+#include "common/screen.h"
+
+static point_t cursor = {0, 0};
+
+static volatile color_t font_bg        = {0x00, 0x00, 0x00, 0x00};
+static volatile color_t font_normal_fg = {0xC0, 0xC0, 0xC0, 0x00};
+static volatile color_t font_error_fg  = {0x00, 0x00, 0xC0, 0x00};
+static volatile color_t font_fg;
+
+const unsigned long long int * font (int c);
+
+void printc (char c);
+void printc_location (point_t point, char c);
+
+void putc_screen (void * p, char c);
+
+void font_set_normal (void);
+void font_set_error (void);
+
+#endif
diff --git a/bulb/include/common/gpu.h b/bulb/include/common/gpu.h
new file mode 100644
index 0000000..1237103
--- /dev/null
+++ b/bulb/include/common/gpu.h
@@ -0,0 +1,57 @@
+#ifndef _ROSE_C_GPU_H
+#define _ROSE_C_GPU_H
+
+#include "common/printf.h"
+
+#include "common/stdbool.h"
+#include "common/stddef.h"
+#include "kernel/mailbox.h"
+#include "kernel/mm.h"
+#include "kernel/peripherals/gpu.h"
+
+// Reference:
+// https://jsandler18.github.io/extra/prop-channel.html
+
+// Uncomment to override physical / virtual screen size with the values defined below
+#define GPU_OVERRIDE_PHYSICAL_SCREEN
+
+#define GPU_SCREEN_WIDTH  1920// Width used if Override is enabled
+#define GPU_SCREEN_HEIGHT 1080// Height used if Override is enabled
+
+#define GPU_VIRTUAL_WIDTH  GPU_SCREEN_WIDTH
+#define GPU_VIRTUAL_HEIGHT GPU_SCREEN_HEIGHT
+
+#define GPU_COLOUR_DEPTH 32
+
+#define VC_SDRAM_OFFSET 0x3FFFFFFF
+
+typedef struct {
+    byte_t blue;
+    byte_t green;
+    byte_t red;
+    byte_t alpha;
+} color_t;
+
+typedef struct {
+    color_t *    fb;
+    unsigned int fb_size;
+    short        virtual_width;
+    short        virtual_height;
+    short        pitch;
+    short        colour_depth;
+} fb_info_t;
+
+static volatile unsigned int __attribute__ ((aligned (16))) gpu_msg_buffer[128];
+
+static fb_info_t fb_info;
+
+bool init_gpu (void);
+
+color_t * get_fb (void);
+
+fb_info_t const * get_fb_info (void);
+
+bool blank_screen (bool blank);
+bool toggle_blank_screen (void);
+
+#endif//_ROSE_C_GPU_H
\ No newline at end of file
diff --git a/bulb/include/common/logging.h b/bulb/include/common/logging.h
new file mode 100644
index 0000000..6203d6b
--- /dev/null
+++ b/bulb/include/common/logging.h
@@ -0,0 +1,27 @@
+#ifndef _ROSE_C_LOGGING_H
+#define _ROSE_C_LOGGING_H
+
+#include "common/printf.h"
+
+#define LOG(msg)                                                           \
+    do {                                                                   \
+        static int __counter__ = 0;                                        \
+        printf (__FILE__ ":%d:[%d] %s\r\n", __LINE__, __counter__++, msg); \
+    } while (0)
+
+#define ERROR(msg)                                                         \
+    do {                                                                   \
+        static int __counter__ = 0;                                        \
+        font_set_error ();                                                 \
+        printf (__FILE__ ":%d:[%d] %s\r\n", __LINE__, __counter__++, msg); \
+        font_set_normal ();                                                \
+    } while (0)
+
+#define ASSERT(expr)                  \
+    do {                              \
+        if (! (expr))                 \
+            LOG ("Assertion failed"); \
+    } while (0)
+
+
+#endif /*_ROSE_C_LOGGING_H*/
diff --git a/bulb/include/common/printf.h b/bulb/include/common/printf.h
new file mode 100644
index 0000000..382087b
--- /dev/null
+++ b/bulb/include/common/printf.h
@@ -0,0 +1,107 @@
+/*
+File: printf.h
+
+Copyright (C) 2004  Kustaa Nyholm
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+This library is really just two files: 'printf.h' and 'printf.c'.
+
+They provide a simple and small (+200 loc) printf functionality to
+be used in embedded systems.
+
+I've found them so usefull in debugging that I do not bother with a
+debugger at all.
+
+They are distributed in source form, so to use them, just compile them
+into your project.
+
+Two printf variants are provided: printf and sprintf.
+
+The formats supported by this implementation are: 'd' 'u' 'c' 's' 'x' 'X'.
+
+Zero padding and field width are also supported.
+
+If the library is compiled with 'PRINTF_SUPPORT_LONG' defined then the
+long specifier is also
+supported. Note that this will pull in some long math routines (pun intended!)
+and thus make your executable noticably longer.
+
+The memory foot print of course depends on the target cpu, compiler and
+compiler options, but a rough guestimate (based on a H8S target) is about
+1.4 kB for code and some twenty 'int's and 'char's, say 60 bytes of stack space.
+Not too bad. Your milage may vary. By hacking the source code you can
+get rid of some hunred bytes, I'm sure, but personally I feel the balance of
+functionality and flexibility versus  code size is close to optimal for
+many embedded systems.
+
+To use the printf you need to supply your own character output function,
+something like :
+
+	void putc ( void* p, char c)
+		{
+		while (!SERIAL_PORT_EMPTY) ;
+		SERIAL_PORT_TX_REGISTER = c;
+		}
+
+Before you can call printf you need to initialize it to use your
+character output function with something like:
+
+	init_printf(NULL,putc);
+
+Notice the 'NULL' in 'init_printf' and the parameter 'void* p' in 'putc',
+the NULL (or any pointer) you pass into the 'init_printf' will eventually be
+passed to your 'putc' routine. This allows you to pass some storage space (or
+anything really) to the character output function, if necessary.
+This is not often needed but it was implemented like that because it made
+implementing the sprintf function so neat (look at the source code).
+
+The code is re-entrant, except for the 'init_printf' function, so it
+is safe to call it from interupts too, although this may result in mixed output.
+If you rely on re-entrancy, take care that your 'putc' function is re-entrant!
+
+The printf and sprintf functions are actually macros that translate to
+'tfp_printf' and 'tfp_sprintf'. This makes it possible
+to use them along with 'stdio.h' printf's in a single source file.
+You just need to undef the names before you include the 'stdio.h'.
+Note that these are not function like macros, so if you have variables
+or struct members with these names, things will explode in your face.
+Without variadic macros this is the best we can do to wrap these
+fucnction. If it is a problem just give up the macros and use the
+functions directly or rename them.
+
+For further details see source code.
+
+regs Kusti, 23.10.2004
+*/
+
+
+#ifndef __TFP_PRINTF__
+#define __TFP_PRINTF__
+
+#include <stdarg.h>
+
+void init_printf (void * putp, void (*putf) (void *, char));
+
+void tfp_printf (char * fmt, ...);
+
+void tfp_sprintf (char * s, char * fmt, ...);
+
+void tfp_format (void * putp, void (*putf) (void *, char), char * fmt, va_list va);
+
+#define printf  tfp_printf
+#define sprintf tfp_sprintf
+
+#endif
diff --git a/bulb/include/common/screen.h b/bulb/include/common/screen.h
new file mode 100644
index 0000000..3e969d7
--- /dev/null
+++ b/bulb/include/common/screen.h
@@ -0,0 +1,20 @@
+#ifndef _ROSE_C_SCREEN_H
+#define _ROSE_C_SCREEN_H
+#include "common/gpu.h"
+
+typedef struct {
+    unsigned int x, y;
+} point_t;
+
+// point_t point (unsigned int x, unsigned int y);
+#define POINT(x, y) \
+    (point_t) {     \
+        x, y        \
+    }
+
+void drawpx (point_t p, color_t color);
+
+short get_max_width ();
+short get_max_height ();
+
+#endif//_ROSE_C_SCREEN_H
diff --git a/bulb/include/common/status_led.h b/bulb/include/common/status_led.h
new file mode 100644
index 0000000..0a7096e
--- /dev/null
+++ b/bulb/include/common/status_led.h
@@ -0,0 +1,24 @@
+#ifndef _ROSE_C_STATUS_LED_H
+#define _ROSE_C_STATUS_LED_H
+
+#include "common/stdbool.h"
+#include "kernel/mailbox.h"
+
+// Following https://github.com/mathlizee/Rasperry-Pi-3
+
+enum {
+    STATUS_LED = 42,
+    POWER_LED  = 130
+};
+
+static volatile unsigned int __attribute__ ((aligned (16))) led_msg_buffer[32];
+
+
+bool get_led (int pin);
+
+void set_led (bool status, int pin);
+
+bool toggle_led (int pin);
+
+
+#endif//_ROSE_C_STATUS_LED_H
diff --git a/bulb/include/common/stdbool.h b/bulb/include/common/stdbool.h
new file mode 100644
index 0000000..2c03282
--- /dev/null
+++ b/bulb/include/common/stdbool.h
@@ -0,0 +1,10 @@
+#ifndef _ROSE_C_BOOL_H
+#define _ROSE_C_BOOL_H
+
+#define true 1
+#define false 0
+#define __bool_true_false_are_defined
+
+typedef char bool;
+
+#endif /*_ROSE_C_BOOL_H*/
diff --git a/bulb/include/common/stddef.h b/bulb/include/common/stddef.h
new file mode 100644
index 0000000..8d9feaa
--- /dev/null
+++ b/bulb/include/common/stddef.h
@@ -0,0 +1,10 @@
+#ifndef _ROSE_C_STDDEF_H
+#define _ROSE_C_STDDEF_H
+
+#define NULL 0
+
+#define ptr_t unsigned long
+
+#define byte_t unsigned char
+
+#endif//_ROSE_C_STDDEF_H
\ No newline at end of file
diff --git a/bulb/include/common/utils.h b/bulb/include/common/utils.h
new file mode 100644
index 0000000..29b53a1
--- /dev/null
+++ b/bulb/include/common/utils.h
@@ -0,0 +1,12 @@
+#ifndef _ROSE_C_BOOT_H
+#define _ROSE_C_BOOT_H
+
+extern void delay (unsigned long);
+
+extern void put32 (unsigned long, unsigned int);
+
+extern unsigned int get32 (unsigned long);
+
+extern int get_el (void);
+
+#endif /*_ROSE_C_BOOT_H */
diff --git a/bulb/include/kernel/arm/sysregs.h b/bulb/include/kernel/arm/sysregs.h
new file mode 100644
index 0000000..98acd8b
--- /dev/null
+++ b/bulb/include/kernel/arm/sysregs.h
@@ -0,0 +1,49 @@
+#ifndef _ROSE_K_A_SYSREGS_H
+#define _ROSE_K_A_SYSREGS_H
+
+// ***************************************
+// SCTLR_EL1, System Control Register (EL1), Page 2654 of AArch64-Reference-Manual.
+// ***************************************
+
+#define SCTLR_RESERVED          (3 << 28) | (3 << 22) | (1 << 20) | (1 << 11)
+#define SCTLR_EE_LITTLE_ENDIAN  (0 << 25)
+#define SCTLR_EOE_LITTLE_ENDIAN (0 << 24)
+#define SCTLR_I_CACHE_DISABLED  (0 << 12)
+#define SCTLR_D_CACHE_DISABLED  (0 << 2)
+#define SCTLR_MMU_DISABLED      (0 << 0)
+#define SCTLR_MMU_ENABLED       (1 << 0)
+
+#define SCTLR_VALUE_MMU_DISABLED (SCTLR_RESERVED | SCTLR_EE_LITTLE_ENDIAN | SCTLR_I_CACHE_DISABLED | SCTLR_D_CACHE_DISABLED | SCTLR_MMU_DISABLED)
+
+// ***************************************
+// HCR_EL2, Hypervisor Configuration Register (EL2), Page 2487 of AArch64-Reference-Manual.
+// ***************************************
+
+#define HCR_RW    (1 << 31)
+#define HCR_VALUE HCR_RW
+
+// ***************************************
+// SCR_EL3, Secure Configuration Register (EL3), Page 2648 of AArch64-Reference-Manual.
+// ***************************************
+
+#define SCR_RESERVED (3 << 4)
+#define SCR_RW       (1 << 10)
+#define SCR_NS       (1 << 0)
+#define SCR_VALUE    (SCR_RESERVED | SCR_RW | SCR_NS)
+
+// ***************************************
+// SPSR_EL3, Saved Program Status Register (EL3) Page 389 of AArch64-Reference-Manual.
+// ***************************************
+
+#define SPSR_MASK_ALL (7 << 6)
+#define SPSR_EL1h     (5 << 0)
+#define SPSR_VALUE    (SPSR_MASK_ALL | SPSR_EL1h)
+
+// ***************************************
+// ESR_EL1, Exception Syndrome Register (EL1). Page 2431 of AArch64-Reference-Manual.
+// ***************************************
+
+#define ESR_ELx_EC_SHIFT 26
+#define ESR_ELx_EC_SVC64 0x15
+
+#endif /*_ROSE_K_A_SYSREGS_H*/
diff --git a/bulb/include/kernel/entry.h b/bulb/include/kernel/entry.h
new file mode 100644
index 0000000..0152f82
--- /dev/null
+++ b/bulb/include/kernel/entry.h
@@ -0,0 +1,35 @@
+#ifndef _ROSE_K_ENTRY_H
+#define _ROSE_K_ENTRY_H
+
+#define S_FRAME_SIZE 272// size of all saved registers
+#define S_X0         0  // offset of x0 register in saved stack frame
+
+#define SYNC_INVALID_EL1t  0
+#define IRQ_INVALID_EL1t   1
+#define FIQ_INVALID_EL1t   2
+#define ERROR_INVALID_EL1t 3
+
+#define SYNC_INVALID_EL1h  4
+#define IRQ_INVALID_EL1h   5
+#define FIQ_INVALID_EL1h   6
+#define ERROR_INVALID_EL1h 7
+
+#define SYNC_INVALID_EL0_64  8
+#define IRQ_INVALID_EL0_64   9
+#define FIQ_INVALID_EL0_64   10
+#define ERROR_INVALID_EL0_64 11
+
+#define SYNC_INVALID_EL0_32  12
+#define IRQ_INVALID_EL0_32   13
+#define FIQ_INVALID_EL0_32   14
+#define ERROR_INVALID_EL0_32 15
+
+#define SYNC_ERROR    16
+#define SYSCALL_ERROR 17
+
+#ifndef __ASSEMBLER__
+
+void ret_from_fork (void);
+
+#endif
+#endif
diff --git a/bulb/include/kernel/mailbox.h b/bulb/include/kernel/mailbox.h
new file mode 100644
index 0000000..b4f6dd8
--- /dev/null
+++ b/bulb/include/kernel/mailbox.h
@@ -0,0 +1,40 @@
+#ifndef _ROSE_K_MAILBOX_H
+#define _ROSE_K_MAILBOX_H
+
+#include "common/stdbool.h"
+#include "common/stddef.h"
+#include "common/utils.h"
+#include "kernel/mm.h"
+#include "kernel/peripherals/mailbox.h"
+
+#include "common/debug.h"
+#include "common/logging.h"
+
+#define DUMP_BUFFER false
+
+// Documentation:
+// https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
+
+typedef enum {
+    POWER = 0,
+    FRAMEBUFFER,
+    VIRTUAL_UART,
+    VCHIQ,
+    LEDS,
+    BUTTONS,
+    TOUCH_SCREEN,
+    RESERVED,
+    PROPERTY_ARM_VC,// Request from ARM for response by VC
+    PROPERTY_VC_ARM // Request from VC for response by ARM (Currently not in use)
+} channel_t;
+
+
+typedef struct {
+    unsigned int data    : 28;// most significant bits contain shared memory address
+    channel_t    channel : 4; // least four significant bits contain channel
+} mbox_message_t;
+
+// Send message and check responses
+bool mailbox_request (volatile unsigned int * data_ptr, channel_t channel);
+
+#endif//_ROSE_K_MAILBOX_H
diff --git a/bulb/include/kernel/mm.h b/bulb/include/kernel/mm.h
new file mode 100644
index 0000000..7acc222
--- /dev/null
+++ b/bulb/include/kernel/mm.h
@@ -0,0 +1,33 @@
+#ifndef _ROSE_K_MM_H
+#define _ROSE_K_MM_H
+
+#include "common/stddef.h"
+#include "peripherals/base.h"
+
+#define PAGE_SHIFT    12
+#define TABLE_SHIFT   9
+#define SECTION_SHIFT (PAGE_SHIFT + TABLE_SHIFT)
+
+#define PAGE_SIZE    (1 << PAGE_SHIFT)
+#define SECTION_SIZE (1 << SECTION_SHIFT)
+
+#define LOW_MEMORY  (2 * SECTION_SIZE)
+#define HIGH_MEMORY 0x70000000
+
+#define PAGING_MEMORY (HIGH_MEMORY - LOW_MEMORY)
+#define PAGING_PAGES  (PAGING_MEMORY / PAGE_SIZE)
+
+#ifndef __ASSEMBLER__
+
+extern char _start;
+#define KERNEL_START ((ptr_t) &_start)
+
+ptr_t get_free_page ();
+
+void free_page (ptr_t p);
+
+void memzero (ptr_t src, ptr_t n);
+
+#endif
+
+#endif /*_ROSE_K_MM_H */
diff --git a/bulb/include/kernel/mmu.h b/bulb/include/kernel/mmu.h
new file mode 100644
index 0000000..3db2fbe
--- /dev/null
+++ b/bulb/include/kernel/mmu.h
@@ -0,0 +1,38 @@
+#ifndef _ROSE_MMU_H
+#define _ROSE_MMU_H
+
+// Implementation taken from
+// https://github.com/bztsrc/raspi3-tutorial/blob/master/10_virtualmemory/mmu.c
+
+#include "common/logging.h"
+#include "kernel/peripherals/base.h"
+
+#define PAGESIZE 4096
+
+// granularity
+#define PT_PAGE   0b11// 4k granule
+#define PT_BLOCK  0b01// 2M granule
+// accessibility
+#define PT_KERNEL (0 << 6)   // privileged, supervisor EL1 access only
+#define PT_USER   (1 << 6)   // unprivileged, EL0 access allowed
+#define PT_RW     (0 << 7)   // read-write
+#define PT_RO     (1 << 7)   // read-only
+#define PT_AF     (1 << 10)  // accessed flag
+#define PT_NX     (1UL << 54)// no execute
+// shareability
+#define PT_OSH    (2 << 8)// outter shareable
+#define PT_ISH    (3 << 8)// inner shareable
+// defined in MAIR register
+#define PT_MEM    (0 << 2)// normal memory
+#define PT_DEV    (1 << 2)// device MMIO
+#define PT_NC     (2 << 2)// non-cachable
+
+#define TTBR_CNP 1
+
+// get addresses from linker
+extern volatile unsigned char _data;
+extern volatile unsigned char _end;
+
+void init_mmu (void);
+
+#endif//_ROSE_MMU_H
\ No newline at end of file
diff --git a/bulb/include/kernel/peripherals/base.h b/bulb/include/kernel/peripherals/base.h
new file mode 100644
index 0000000..12f55d7
--- /dev/null
+++ b/bulb/include/kernel/peripherals/base.h
@@ -0,0 +1,6 @@
+#ifndef _ROSE_K_P_BASE_H
+#define _ROSE_K_P_BASE_H
+
+#define PBASE 0xFE000000
+
+#endif /*_ROSE_K_P_BASE_H */
diff --git a/bulb/include/kernel/peripherals/gpio.h b/bulb/include/kernel/peripherals/gpio.h
new file mode 100644
index 0000000..8354caf
--- /dev/null
+++ b/bulb/include/kernel/peripherals/gpio.h
@@ -0,0 +1,12 @@
+#ifndef _ROSE_K_P_GPIO_H
+#define _ROSE_K_P_GPIO_H
+
+#include "kernel/peripherals/base.h"
+
+#define GPFSEL1   (PBASE + 0x00200004)
+#define GPSET0    (PBASE + 0x0020001C)
+#define GPCLR0    (PBASE + 0x00200028)
+#define GPPUD     (PBASE + 0x00200094)
+#define GPPUDCLK0 (PBASE + 0x00200098)
+
+#endif /*_ROSE_K_P_GPIO_H */
diff --git a/bulb/include/kernel/peripherals/gpu.h b/bulb/include/kernel/peripherals/gpu.h
new file mode 100644
index 0000000..2408fba
--- /dev/null
+++ b/bulb/include/kernel/peripherals/gpu.h
@@ -0,0 +1,10 @@
+#ifndef _ROSE_K_P_GPU_H
+#define _ROSE_K_P_GPU_H
+
+#define GPU_REQUEST_FRAMEBUFFER 0x40001
+#define GPU_BLANK_SCREEN        0x40002
+#define GPU_SET_SCREEN_SIZE     0x48003
+#define GPU_SET_VIRTUAL_SIZE    0x48004
+#define GPU_SET_COLOUR_DEPTH    0x48005
+
+#endif//_ROSE_K_P_GPU_H
\ No newline at end of file
diff --git a/bulb/include/kernel/peripherals/mailbox.h b/bulb/include/kernel/peripherals/mailbox.h
new file mode 100644
index 0000000..37f664c
--- /dev/null
+++ b/bulb/include/kernel/peripherals/mailbox.h
@@ -0,0 +1,19 @@
+#ifndef _ROSE_K_P_MAILBOX_H
+#define _ROSE_K_P_MAILBOX_H
+
+#include "base.h"
+
+#define MBOX0 (PBASE + 0xB880)// Read from CPU
+#define MBOX1 (PBASE + 0xB840)// Write to CPU
+
+#define MBOX_READ   0x00
+#define MBOX_STATUS 0x18
+#define MBOX_IRQ    0x1C
+#define MBOX_WRITE  0x20
+
+#define MBOX_READ_EMPTY (1 << 30)
+#define MBOX_WRITE_FULL (1 << 31)
+
+#define MBOX_SUCCESS 0x80000000
+
+#endif//_ROSE_K_P_MAILBOX_H
\ No newline at end of file
diff --git a/bulb/src/common/debug.c b/bulb/src/common/debug.c
new file mode 100644
index 0000000..4a65209
--- /dev/null
+++ b/bulb/src/common/debug.c
@@ -0,0 +1,29 @@
+#include "common/debug.h"
+
+void print_hex (unsigned char dec) {
+    char fst = dec / 16;
+    char snd = dec % 16;
+    fst      = (fst > 9) ? 'A' + fst - 10 : '0' + fst;
+    snd      = (snd > 9) ? 'A' + snd - 10 : '0' + snd;
+    printf ("%c%c ", fst, snd);
+}
+
+void hex_dump (byte_t * array) {
+    for (int i = 0; i < *(unsigned int *) array;) {
+        i += 4;
+        for (int j = 1; j <= 4; j++) {
+            print_hex (array[i - j]);
+        }
+        printf (" ");
+        if (!(i % 32))
+            printf ("\r\n");
+    }
+    printf ("\r\n");
+}
+
+void int_dump (unsigned int * array) {
+    for (int i = 0; i < *array / 4; i++) {
+        printf ("%d ", array[i]);
+    }
+    printf ("\r\n");
+}
diff --git a/bulb/src/common/font.c b/bulb/src/common/font.c
new file mode 100644
index 0000000..ca66890
--- /dev/null
+++ b/bulb/src/common/font.c
@@ -0,0 +1,195 @@
+#include "common/font.h"
+
+/* From https://github.com/dhepper/font8x8/blob/master/font8x8_block.h */
+const unsigned long long int * font (int c) {
+    static const char f[128][FONT_SIZE] = {
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0000 (nul)
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0001
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0002
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0003
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0004
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0005
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0006
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0007
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0008
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0009
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000A
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000B
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000C
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000D
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000E
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000F
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0010
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0011
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0012
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0013
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0014
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0015
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0016
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0017
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0018
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0019
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001A
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001B
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001C
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001D
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001E
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001F
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0020 (space)
+            {0x18, 0x3C, 0x3C, 0x18, 0x18, 0x00, 0x18, 0x00},// U+0021 (!)
+            {0x36, 0x36, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0022 (")
+            {0x36, 0x36, 0x7F, 0x36, 0x7F, 0x36, 0x36, 0x00},// U+0023 (#)
+            {0x0C, 0x3E, 0x03, 0x1E, 0x30, 0x1F, 0x0C, 0x00},// U+0024 ($)
+            {0x00, 0x63, 0x33, 0x18, 0x0C, 0x66, 0x63, 0x00},// U+0025 (%)
+            {0x1C, 0x36, 0x1C, 0x6E, 0x3B, 0x33, 0x6E, 0x00},// U+0026 (&)
+            {0x06, 0x06, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0027 (')
+            {0x18, 0x0C, 0x06, 0x06, 0x06, 0x0C, 0x18, 0x00},// U+0028 (()
+            {0x06, 0x0C, 0x18, 0x18, 0x18, 0x0C, 0x06, 0x00},// U+0029 ())
+            {0x00, 0x66, 0x3C, 0xFF, 0x3C, 0x66, 0x00, 0x00},// U+002A (*)
+            {0x00, 0x0C, 0x0C, 0x3F, 0x0C, 0x0C, 0x00, 0x00},// U+002B (+)
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x0C, 0x06},// U+002C (,)
+            {0x00, 0x00, 0x00, 0x3F, 0x00, 0x00, 0x00, 0x00},// U+002D (-)
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x0C, 0x00},// U+002E (.)
+            {0x60, 0x30, 0x18, 0x0C, 0x06, 0x03, 0x01, 0x00},// U+002F (/)
+            {0x3E, 0x63, 0x73, 0x7B, 0x6F, 0x67, 0x3E, 0x00},// U+0030 (0)
+            {0x0C, 0x0E, 0x0C, 0x0C, 0x0C, 0x0C, 0x3F, 0x00},// U+0031 (1)
+            {0x1E, 0x33, 0x30, 0x1C, 0x06, 0x33, 0x3F, 0x00},// U+0032 (2)
+            {0x1E, 0x33, 0x30, 0x1C, 0x30, 0x33, 0x1E, 0x00},// U+0033 (3)
+            {0x38, 0x3C, 0x36, 0x33, 0x7F, 0x30, 0x78, 0x00},// U+0034 (4)
+            {0x3F, 0x03, 0x1F, 0x30, 0x30, 0x33, 0x1E, 0x00},// U+0035 (5)
+            {0x1C, 0x06, 0x03, 0x1F, 0x33, 0x33, 0x1E, 0x00},// U+0036 (6)
+            {0x3F, 0x33, 0x30, 0x18, 0x0C, 0x0C, 0x0C, 0x00},// U+0037 (7)
+            {0x1E, 0x33, 0x33, 0x1E, 0x33, 0x33, 0x1E, 0x00},// U+0038 (8)
+            {0x1E, 0x33, 0x33, 0x3E, 0x30, 0x18, 0x0E, 0x00},// U+0039 (9)
+            {0x00, 0x0C, 0x0C, 0x00, 0x00, 0x0C, 0x0C, 0x00},// U+003A (:)
+            {0x00, 0x0C, 0x0C, 0x00, 0x00, 0x0C, 0x0C, 0x06},// U+003B (//)
+            {0x18, 0x0C, 0x06, 0x03, 0x06, 0x0C, 0x18, 0x00},// U+003C (<)
+            {0x00, 0x00, 0x3F, 0x00, 0x00, 0x3F, 0x00, 0x00},// U+003D (=)
+            {0x06, 0x0C, 0x18, 0x30, 0x18, 0x0C, 0x06, 0x00},// U+003E (>)
+            {0x1E, 0x33, 0x30, 0x18, 0x0C, 0x00, 0x0C, 0x00},// U+003F (?)
+            {0x3E, 0x63, 0x7B, 0x7B, 0x7B, 0x03, 0x1E, 0x00},// U+0040 (@)
+            {0x0C, 0x1E, 0x33, 0x33, 0x3F, 0x33, 0x33, 0x00},// U+0041 (A)
+            {0x3F, 0x66, 0x66, 0x3E, 0x66, 0x66, 0x3F, 0x00},// U+0042 (B)
+            {0x3C, 0x66, 0x03, 0x03, 0x03, 0x66, 0x3C, 0x00},// U+0043 (C)
+            {0x1F, 0x36, 0x66, 0x66, 0x66, 0x36, 0x1F, 0x00},// U+0044 (D)
+            {0x7F, 0x46, 0x16, 0x1E, 0x16, 0x46, 0x7F, 0x00},// U+0045 (E)
+            {0x7F, 0x46, 0x16, 0x1E, 0x16, 0x06, 0x0F, 0x00},// U+0046 (F)
+            {0x3C, 0x66, 0x03, 0x03, 0x73, 0x66, 0x7C, 0x00},// U+0047 (G)
+            {0x33, 0x33, 0x33, 0x3F, 0x33, 0x33, 0x33, 0x00},// U+0048 (H)
+            {0x1E, 0x0C, 0x0C, 0x0C, 0x0C, 0x0C, 0x1E, 0x00},// U+0049 (I)
+            {0x78, 0x30, 0x30, 0x30, 0x33, 0x33, 0x1E, 0x00},// U+004A (J)
+            {0x67, 0x66, 0x36, 0x1E, 0x36, 0x66, 0x67, 0x00},// U+004B (K)
+            {0x0F, 0x06, 0x06, 0x06, 0x46, 0x66, 0x7F, 0x00},// U+004C (L)
+            {0x63, 0x77, 0x7F, 0x7F, 0x6B, 0x63, 0x63, 0x00},// U+004D (M)
+            {0x63, 0x67, 0x6F, 0x7B, 0x73, 0x63, 0x63, 0x00},// U+004E (N)
+            {0x1C, 0x36, 0x63, 0x63, 0x63, 0x36, 0x1C, 0x00},// U+004F (O)
+            {0x3F, 0x66, 0x66, 0x3E, 0x06, 0x06, 0x0F, 0x00},// U+0050 (P)
+            {0x1E, 0x33, 0x33, 0x33, 0x3B, 0x1E, 0x38, 0x00},// U+0051 (Q)
+            {0x3F, 0x66, 0x66, 0x3E, 0x36, 0x66, 0x67, 0x00},// U+0052 (R)
+            {0x1E, 0x33, 0x07, 0x0E, 0x38, 0x33, 0x1E, 0x00},// U+0053 (S)
+            {0x3F, 0x2D, 0x0C, 0x0C, 0x0C, 0x0C, 0x1E, 0x00},// U+0054 (T)
+            {0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x3F, 0x00},// U+0055 (U)
+            {0x33, 0x33, 0x33, 0x33, 0x33, 0x1E, 0x0C, 0x00},// U+0056 (V)
+            {0x63, 0x63, 0x63, 0x6B, 0x7F, 0x77, 0x63, 0x00},// U+0057 (W)
+            {0x63, 0x63, 0x36, 0x1C, 0x1C, 0x36, 0x63, 0x00},// U+0058 (X)
+            {0x33, 0x33, 0x33, 0x1E, 0x0C, 0x0C, 0x1E, 0x00},// U+0059 (Y)
+            {0x7F, 0x63, 0x31, 0x18, 0x4C, 0x66, 0x7F, 0x00},// U+005A (Z)
+            {0x1E, 0x06, 0x06, 0x06, 0x06, 0x06, 0x1E, 0x00},// U+005B ([)
+            {0x03, 0x06, 0x0C, 0x18, 0x30, 0x60, 0x40, 0x00},// U+005C (\)
+            {0x1E, 0x18, 0x18, 0x18, 0x18, 0x18, 0x1E, 0x00},// U+005D (])
+            {0x08, 0x1C, 0x36, 0x63, 0x00, 0x00, 0x00, 0x00},// U+005E (^)
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF},// U+005F (_)
+            {0x0C, 0x0C, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0060 (`)
+            {0x00, 0x00, 0x1E, 0x30, 0x3E, 0x33, 0x6E, 0x00},// U+0061 (a)
+            {0x07, 0x06, 0x06, 0x3E, 0x66, 0x66, 0x3B, 0x00},// U+0062 (b)
+            {0x00, 0x00, 0x1E, 0x33, 0x03, 0x33, 0x1E, 0x00},// U+0063 (c)
+            {0x38, 0x30, 0x30, 0x3e, 0x33, 0x33, 0x6E, 0x00},// U+0064 (d)
+            {0x00, 0x00, 0x1E, 0x33, 0x3f, 0x03, 0x1E, 0x00},// U+0065 (e)
+            {0x1C, 0x36, 0x06, 0x0f, 0x06, 0x06, 0x0F, 0x00},// U+0066 (f)
+            {0x00, 0x00, 0x6E, 0x33, 0x33, 0x3E, 0x30, 0x1F},// U+0067 (g)
+            {0x07, 0x06, 0x36, 0x6E, 0x66, 0x66, 0x67, 0x00},// U+0068 (h)
+            {0x0C, 0x00, 0x0E, 0x0C, 0x0C, 0x0C, 0x1E, 0x00},// U+0069 (i)
+            {0x30, 0x00, 0x30, 0x30, 0x30, 0x33, 0x33, 0x1E},// U+006A (j)
+            {0x07, 0x06, 0x66, 0x36, 0x1E, 0x36, 0x67, 0x00},// U+006B (k)
+            {0x0E, 0x0C, 0x0C, 0x0C, 0x0C, 0x0C, 0x1E, 0x00},// U+006C (l)
+            {0x00, 0x00, 0x33, 0x7F, 0x7F, 0x6B, 0x63, 0x00},// U+006D (m)
+            {0x00, 0x00, 0x1F, 0x33, 0x33, 0x33, 0x33, 0x00},// U+006E (n)
+            {0x00, 0x00, 0x1E, 0x33, 0x33, 0x33, 0x1E, 0x00},// U+006F (o)
+            {0x00, 0x00, 0x3B, 0x66, 0x66, 0x3E, 0x06, 0x0F},// U+0070 (p)
+            {0x00, 0x00, 0x6E, 0x33, 0x33, 0x3E, 0x30, 0x78},// U+0071 (q)
+            {0x00, 0x00, 0x3B, 0x6E, 0x66, 0x06, 0x0F, 0x00},// U+0072 (r)
+            {0x00, 0x00, 0x3E, 0x03, 0x1E, 0x30, 0x1F, 0x00},// U+0073 (s)
+            {0x08, 0x0C, 0x3E, 0x0C, 0x0C, 0x2C, 0x18, 0x00},// U+0074 (t)
+            {0x00, 0x00, 0x33, 0x33, 0x33, 0x33, 0x6E, 0x00},// U+0075 (u)
+            {0x00, 0x00, 0x33, 0x33, 0x33, 0x1E, 0x0C, 0x00},// U+0076 (v)
+            {0x00, 0x00, 0x63, 0x6B, 0x7F, 0x7F, 0x36, 0x00},// U+0077 (w)
+            {0x00, 0x00, 0x63, 0x36, 0x1C, 0x36, 0x63, 0x00},// U+0078 (x)
+            {0x00, 0x00, 0x33, 0x33, 0x33, 0x3E, 0x30, 0x1F},// U+0079 (y)
+            {0x00, 0x00, 0x3F, 0x19, 0x0C, 0x26, 0x3F, 0x00},// U+007A (z)
+            {0x38, 0x0C, 0x0C, 0x07, 0x0C, 0x0C, 0x38, 0x00},// U+007B ({)
+            {0x18, 0x18, 0x18, 0x00, 0x18, 0x18, 0x18, 0x00},// U+007C (|)
+            {0x07, 0x0C, 0x0C, 0x38, 0x0C, 0x0C, 0x07, 0x00},// U+007D (})
+            {0x6E, 0x3B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+007E (~)
+            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00} // U+007F
+    };
+    return (unsigned long long int *) f[c];
+}
+
+void printc_location (point_t point, char c) {
+    unsigned char const * bitmap = (unsigned char const *) font (c);
+    for (int i = 0; i < FONT_SIZE; i++) {
+        for (int j = 0; j < FONT_SIZE; j++) {
+            bool is_on = bitmap[i] & (1 << j);
+
+            point_t _point;
+            for (int k = 0; k < FONT_FACTOR; k++) {
+                for (int h = 0; h < FONT_FACTOR; h++) {
+                    _point.x = point.x + j * FONT_FACTOR + k;
+                    _point.y = point.y + i * FONT_FACTOR + h;
+                    drawpx (_point, is_on ? font_fg : font_bg);
+                }
+            }
+        }
+    }
+}
+
+void printc (char c) {
+    // Handle special characters, print otherwise
+    switch (c) {
+        case '\r':// Reset cursor to beginning of line
+            cursor.x = 0;
+            break;
+        case '\n':// Move cursor to next line
+            cursor.y += FONT_REAL_HEIGHT;
+            break;
+        case '\t':// Print minimum one space, then align forwards to tab grid
+            cursor.x += FONT_TAB_REAL_WIDTH - cursor.x % (FONT_TAB_REAL_WIDTH);
+            break;
+        default:// Print character and update cursor
+            // TODO dynamically deal with unprintable characters (i.e., check if bitmap is all '0')
+            printc_location (cursor, c);
+            cursor.x += FONT_REAL_WIDTH;
+    }
+
+    // If next printed char overflowed screen width move cursor to beginning of next line
+    if (cursor.x + FONT_REAL_WIDTH >= get_max_width ()) {
+        cursor.x = 0;
+        cursor.y += FONT_REAL_HEIGHT;
+    }
+    // If next line would overflow screen height (ignoring line spacing) move to beginning of screen
+    if (cursor.y + FONT_REAL_WIDTH - FONT_SPACING >= get_max_height ()) {
+        // TODO clear framebuffer here...?
+        cursor.y = 0;
+    }
+}
+
+void font_set_normal (void) {
+    font_fg = font_normal_fg;
+}
+void font_set_error (void) {
+    font_fg = font_error_fg;
+}
+
+void putc_screen (void * p, char c) {
+    printc (c);
+}
diff --git a/bulb/src/common/gpu.c b/bulb/src/common/gpu.c
new file mode 100644
index 0000000..4b376da
--- /dev/null
+++ b/bulb/src/common/gpu.c
@@ -0,0 +1,137 @@
+#include "common/gpu.h"
+
+bool init_gpu () {
+    {                           // First message: read physical dimensions
+        int c               = 0;// Message size; increment while we write
+        gpu_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
+
+        gpu_msg_buffer[++c] = 0x00040003;// Tag to get physical display width / height
+        gpu_msg_buffer[++c] = 8;         // Size of value buffer
+        gpu_msg_buffer[++c] = 0;         // Response & value buffer size written will be written here
+        gpu_msg_buffer[++c] = 0;         // Get physical screen width    |  Overwritten by actual width
+        gpu_msg_buffer[++c] = 0;         // Get physical screen height   |  Overwritten by actual height
+        gpu_msg_buffer[++c] = 0;         // End tag
+
+        gpu_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
+
+        // If reading physical screen dimension fails exit function
+        if (! mailbox_request (gpu_msg_buffer, PROPERTY_ARM_VC))
+            return false;
+    }
+    {                           // Second message: request frame buffer
+        int c               = 0;// Message size; increment while we write
+        gpu_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
+
+#ifdef GPU_OVERRIDE_PHYSICAL_SCREEN             // If this is set, update physical /virtual dimensions based on constants
+        gpu_msg_buffer[++c]  = 0x00048003;      // Tag to set virtual display width / height
+        gpu_msg_buffer[++c]  = 8;               // Size of value buffer
+        gpu_msg_buffer[++c]  = 0;               // Response & value buffer size written will be written here
+        gpu_msg_buffer[++c]  = GPU_SCREEN_WIDTH;// Set virtual screen width     |  Overwritten by actual virtual width
+        int index_gpu_width  = c;
+        gpu_msg_buffer[++c]  = GPU_SCREEN_HEIGHT;// Set virtual screen height    |  Overwritten by actual virtual height
+        int index_gpu_height = c;
+
+        gpu_msg_buffer[++c] = 0x00048004;       // Tag to set virtual display width / height
+        gpu_msg_buffer[++c] = 8;                // Size of value buffer
+        gpu_msg_buffer[++c] = 0;                // Response & value buffer size written will be written here
+        gpu_msg_buffer[++c] = GPU_VIRTUAL_WIDTH;// Set virtual screen width     |  Overwritten by actual virtual width
+        int index_width     = c;
+        gpu_msg_buffer[++c] = GPU_VIRTUAL_HEIGHT;// Set virtual screen height    |  Overwritten by actual virtual height
+        int index_height    = c;
+#else
+        gpu_msg_buffer[++c] = 0x00048004;// Tag to set virtual display width / height
+        gpu_msg_buffer[++c] = 8;         // Size of value buffer
+        gpu_msg_buffer[++c] = 0;         // Response & value buffer size written will be written here
+        gpu_msg_buffer[++c];             //GPU_SCREEN_WIDTH;      // Reuse previous width         |  Overwritten by actual virtual width
+        int index_width = c;
+        gpu_msg_buffer[++c];//GPU_SCREEN_HEIGHT;     // Reuse previous height        |  Overwritten by actual virtual height
+        int index_height = c;
+#endif
+
+        gpu_msg_buffer[++c] = 0x00048005;      // Tag to set pixel depth
+        gpu_msg_buffer[++c] = 4;               // Size of value buffer
+        gpu_msg_buffer[++c] = 0;               // Response & value buffer size written will be written here
+        gpu_msg_buffer[++c] = GPU_COLOUR_DEPTH;// Set colour depth             |  Overwritten by actual colour depth
+
+        gpu_msg_buffer[++c]   = 0x00040001;// Tag to allocate framebuffer
+        gpu_msg_buffer[++c]   = 8;         // Size of value buffer
+        gpu_msg_buffer[++c]   = 0;         // Response & value buffer size will be written here
+        gpu_msg_buffer[++c]   = 16;        // Buffer alignment             |  Overwritten by pointer to framebuffer
+        int index_framebuffer = c;
+        gpu_msg_buffer[++c]   = 0;// Unused - will be overwritten |  Overwritten by size of framebuffer
+        int index_fb_size     = c;
+
+        gpu_msg_buffer[++c] = 0;// End tag
+        gpu_msg_buffer[++c] = 0;// Padding
+        gpu_msg_buffer[++c] = 0;// Padding
+        gpu_msg_buffer[++c] = 0;// Padding
+
+        gpu_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
+
+        // If message failed exit
+        if (! mailbox_request (gpu_msg_buffer, PROPERTY_ARM_VC))
+            return false;
+
+        // Since message succeeded, update frame buffer and its size
+        fb_info.fb      = (color_t *) (long) (gpu_msg_buffer[index_framebuffer] & VC_SDRAM_OFFSET);
+        fb_info.fb_size = gpu_msg_buffer[index_fb_size];
+
+        // printf ("PHY_WIDTH: %d, PHY_HEIGHT: %d, VIRT_WIDTH: %d, VIRT_HEIGHT: %d\n\r", gpu_msg_buffer[index_gpu_width], gpu_msg_buffer[index_gpu_height], gpu_msg_buffer[index_width], gpu_msg_buffer[index_height]);
+
+        fb_info.virtual_width  = gpu_msg_buffer[index_width];
+        fb_info.virtual_height = gpu_msg_buffer[index_height];
+    }
+    {                           // Third message: read pitch (in bytes per line)
+        int c               = 0;// Message size; increment while we write
+        gpu_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
+
+        gpu_msg_buffer[++c] = 0x00040008;// Tag to get pitch
+        gpu_msg_buffer[++c] = 4;         // Size of value buffer
+        gpu_msg_buffer[++c] = 0;         // Response & value buffer size written will be written here
+        gpu_msg_buffer[++c] = 0;         // Pitch will be written here
+        int index_pitch     = c;
+
+        gpu_msg_buffer[++c] = 0;// End tag
+        gpu_msg_buffer[++c] = 0;// Padding
+
+        gpu_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
+
+        // If message failed exit
+        if (! mailbox_request (gpu_msg_buffer, PROPERTY_ARM_VC))
+            return false;
+
+        // Else write pitch appropriately
+        fb_info.pitch = gpu_msg_buffer[index_pitch];
+    }
+    return true;
+}
+
+color_t * get_fb () {
+    return fb_info.fb;
+}
+
+fb_info_t const * get_fb_info () {
+    return &fb_info;
+}
+
+bool blank_screen (bool blank) {
+    int c               = 0;// Message size; increment while we write
+    gpu_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
+
+    gpu_msg_buffer[++c] = 0x00040002;// Tag to blank screen
+    gpu_msg_buffer[++c] = 4;         // Size of value buffer
+    gpu_msg_buffer[++c] = 0;         //
+    gpu_msg_buffer[++c] = blank;     // On or off
+
+    gpu_msg_buffer[++c] = 0;// End tag
+    gpu_msg_buffer[++c] = 0;// Padding
+
+    gpu_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
+
+    return mailbox_request (gpu_msg_buffer, PROPERTY_ARM_VC);
+}
+
+bool toggle_blank_screen (void) {
+    static bool is_blank = false;
+    blank_screen (is_blank = ! is_blank);
+}
\ No newline at end of file
diff --git a/bulb/src/common/printf.c b/bulb/src/common/printf.c
new file mode 100644
index 0000000..059ee24
--- /dev/null
+++ b/bulb/src/common/printf.c
@@ -0,0 +1,243 @@
+/*
+File: printf.c
+
+Copyright (C) 2004  Kustaa Nyholm
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+*/
+
+#include "common/printf.h"
+
+typedef void (*putcf) (void *, char);
+
+static putcf  stdout_putf;
+static void * stdout_putp;
+
+
+#ifdef PRINTF_LONG_SUPPORT
+
+static void uli2a (unsigned long int num, unsigned int base, int uc, char * bf) {
+    int          n = 0;
+    unsigned int d = 1;
+    while (num / d >= base)
+        d *= base;
+    while (d != 0) {
+        int dgt = num / d;
+        num %= d;
+        d /= base;
+        if (n || dgt > 0 || d == 0) {
+            *bf++ = dgt + (dgt < 10 ? '0' : (uc ? 'A' : 'a') - 10);
+            ++n;
+        }
+    }
+    *bf = 0;
+}
+
+static void li2a (long num, char * bf) {
+    if (num < 0) {
+        num   = -num;
+        *bf++ = '-';
+    }
+    uli2a (num, 10, 0, bf);
+}
+
+#endif
+
+static void ui2a (unsigned int num, unsigned int base, int uc, char * bf) {
+    int          n = 0;
+    unsigned int d = 1;
+    while (num / d >= base)
+        d *= base;
+    while (d != 0) {
+        int dgt = num / d;
+        num %= d;
+        d /= base;
+        if (n || dgt > 0 || d == 0) {
+            *bf++ = dgt + (dgt < 10 ? '0' : (uc ? 'A' : 'a') - 10);
+            ++n;
+        }
+    }
+    *bf = 0;
+}
+
+static void i2a (int num, char * bf) {
+    if (num < 0) {
+        num   = -num;
+        *bf++ = '-';
+    }
+    ui2a (num, 10, 0, bf);
+}
+
+static int a2d (char ch) {
+    if (ch >= '0' && ch <= '9') {
+        return ch - '0';
+    } else if (ch >= 'a' && ch <= 'f') {
+        return ch - 'a' + 10;
+    } else if (ch >= 'A' && ch <= 'F') {
+        return ch - 'A' + 10;
+    } else {
+        return -1;
+    }
+}
+
+static char a2i (char ch, char ** src, int base, int * nump) {
+    char * p   = *src;
+    int    num = 0;
+    int    digit;
+    while ((digit = a2d (ch)) >= 0) {
+        if (digit > base)
+            break;
+        num = num * base + digit;
+        ch  = *p++;
+    }
+    *src  = p;
+    *nump = num;
+    return ch;
+}
+
+static void putchw (void * putp, putcf putf, int n, char z, char * bf) {
+    char   fc = z ? '0' : ' ';
+    char   ch;
+    char * p = bf;
+    while (*p++ && n > 0)
+        n--;
+    while (n-- > 0)
+        putf (putp, fc);
+    while ((ch = *bf++))
+        putf (putp, ch);
+}
+
+void tfp_format (void * putp, putcf putf, char * fmt, va_list va) {
+    char bf[12];
+
+    char ch;
+
+
+    while ((ch = *(fmt++))) {
+        if (ch != '%') {
+            putf (putp, ch);
+        } else {
+            char lz = 0;
+#ifdef PRINTF_LONG_SUPPORT
+            char lng = 0;
+#endif
+            int w = 0;
+            ch    = *(fmt++);
+            if (ch == '0') {
+                ch = *(fmt++);
+                lz = 1;
+            }
+            if (ch >= '0' && ch <= '9') {
+                ch = a2i (ch, &fmt, 10, &w);
+            }
+#ifdef PRINTF_LONG_SUPPORT
+            if (ch == 'l') {
+                ch  = *(fmt++);
+                lng = 1;
+            }
+#endif
+            switch (ch) {
+                case 0:
+                    goto abort;
+                case 'u': {
+#ifdef PRINTF_LONG_SUPPORT
+                    if (lng)
+                        uli2a (va_arg (va, unsigned long int), 10, 0, bf);
+                    else
+#endif
+                    ui2a (va_arg (va,
+                                  unsigned int), 10, 0, bf);
+                    putchw (putp, putf, w, lz, bf);
+                    break;
+                }
+                case 'd': {
+#ifdef PRINTF_LONG_SUPPORT
+                    if (lng)
+                        li2a (va_arg (va, unsigned long int), bf);
+                    else
+#endif
+                    i2a (va_arg (va,
+                                 int), bf);
+                    putchw (putp, putf, w, lz, bf);
+                    break;
+                }
+                case 'x':
+                case 'X':
+#ifdef PRINTF_LONG_SUPPORT
+                    if (lng)
+                        uli2a (va_arg (va, unsigned long int), 16, (ch == 'X'), bf);
+                    else
+#endif
+                    ui2a (va_arg (va,
+                                  unsigned int), 16, (ch == 'X'), bf);
+                    putchw (putp, putf, w, lz, bf);
+                    break;
+                case 'c' :
+                    putf (putp, (char) (va_arg (va,
+                                                int)));
+                    break;
+                case 's' :
+                    putchw (putp, putf, w, 0, va_arg (va,
+                                                      char*));
+                    break;
+                case 'p':
+                case 'P':
+                    putf (putp, '0');
+                    putf (putp, 'x');
+#ifdef PRINTF_LONG_SUPPORT
+                    if (lng)
+                        uli2a (va_arg (va, unsigned long int), 16, (ch == 'P'), bf);
+                    else
+#endif
+                    ui2a (va_arg (va,
+                                  unsigned int), 16, (ch == 'P'), bf);
+                    putchw (putp, putf, w, lz, bf);
+                    break;
+                case '%':
+                    putf (putp, ch);
+                default:
+                    break;
+            }
+        }
+    }
+abort:;
+}
+
+
+void init_printf (void * putp, void (*putf) (void *, char)) {
+    stdout_putf = putf;
+    stdout_putp = putp;
+}
+
+void tfp_printf (char * fmt, ...) {
+    va_list va;
+    va_start (va, fmt);
+    tfp_format (stdout_putp, stdout_putf, fmt, va);
+    va_end (va);
+}
+
+static void putcp (void * p, char c) {
+    *(*((char **) p))++ = c;
+}
+
+
+void tfp_sprintf (char * s, char * fmt, ...) {
+    va_list va;
+    va_start (va, fmt);
+    tfp_format (&s, putcp, fmt, va);
+    putcp (&s, 0);
+    va_end (va);
+}
diff --git a/bulb/src/common/screen.c b/bulb/src/common/screen.c
new file mode 100644
index 0000000..b09764d
--- /dev/null
+++ b/bulb/src/common/screen.c
@@ -0,0 +1,14 @@
+#include "common/screen.h"
+
+void drawpx (point_t p, color_t color) {
+    unsigned long int location = p.y * (get_fb_info ()->pitch) / sizeof (color_t) + p.x;
+    get_fb ()[location]        = color;
+};
+
+short get_max_width () {
+    return get_fb_info ()->virtual_width - 1;
+}
+
+short get_max_height () {
+    return get_fb_info ()->virtual_height - 1;
+}
diff --git a/bulb/src/common/status_led.c b/bulb/src/common/status_led.c
new file mode 100644
index 0000000..b8b1b03
--- /dev/null
+++ b/bulb/src/common/status_led.c
@@ -0,0 +1,55 @@
+#include "common/status_led.h"
+
+bool get_led (int pin) {
+    // Try to read ACT LED state
+    int c               = 0;// Message size; increment while we write
+    led_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
+
+    led_msg_buffer[++c] = 0x00030041;// Tag to get ACT LED state
+    led_msg_buffer[++c] = 8;         // Size of value buffer
+    led_msg_buffer[++c] = 0;         // Response & value buffer size written will be written here
+    led_msg_buffer[++c] = pin;       //
+    led_msg_buffer[++c] = 0;         //
+    int index_led       = c;
+
+    led_msg_buffer[++c] = 0;// End tag
+
+    led_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
+
+    if (! mailbox_request (led_msg_buffer, PROPERTY_ARM_VC)) {
+        printf ("ERROR\r\n");
+    };
+    return ! led_msg_buffer[index_led];
+}
+
+/**
+ * Change LED state
+ * Pins:
+ *  - Power LED: 130 (0 to turn on and 1 to turn off)
+ *  - ACT LED: 42 (1 to turn on and 0 to turn off)
+**/
+void set_led (bool status, int pin) {
+    // Try to read ACT LED state
+    int c               = 0;// Message size; increment while we write
+    led_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
+
+    led_msg_buffer[++c] = 0x00038041;// Tag to get ACT LED state
+    led_msg_buffer[++c] = 8;         // Size of value buffer
+    led_msg_buffer[++c] = 0;         // Response & value buffer size written will be written here
+    led_msg_buffer[++c] = pin;
+    led_msg_buffer[++c] = status;
+
+    led_msg_buffer[++c] = 0;// End tag
+
+    led_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
+
+    if (! mailbox_request (led_msg_buffer, PROPERTY_ARM_VC)) {
+        printf ("ERROR\r\n");
+    };
+}
+
+bool toggle_led (int pin) {
+    bool status = get_led (pin);
+    set_led (status, pin);
+    return status;
+}
diff --git a/bulb/src/common/utils.S b/bulb/src/common/utils.S
new file mode 100644
index 0000000..44be485
--- /dev/null
+++ b/bulb/src/common/utils.S
@@ -0,0 +1,21 @@
+.globl get_el
+get_el:
+	mrs x0, CurrentEL
+	lsr x0, x0, #2
+	ret
+
+.globl put32
+put32:
+	str w1,[x0]
+	ret
+
+.globl get32
+get32:
+	ldr w0,[x0]
+	ret
+
+.globl delay
+delay:
+	subs x0, x0, #1
+	bne delay
+	ret
diff --git a/bulb/src/config.txt b/bulb/src/config.txt
new file mode 100644
index 0000000..1cb4eed
--- /dev/null
+++ b/bulb/src/config.txt
@@ -0,0 +1,2 @@
+enable_uart=1
+dtparam=watchdog=on
diff --git a/bulb/src/kernel/boot.S b/bulb/src/kernel/boot.S
new file mode 100644
index 0000000..14bc88a
--- /dev/null
+++ b/bulb/src/kernel/boot.S
@@ -0,0 +1,52 @@
+#include "kernel/arm/sysregs.h"
+
+#include "kernel/mm.h"
+
+.section ".text.boot"
+
+.globl _start
+_start:
+	mrs	x0, mpidr_el1
+	and	x0, x0,#0xFF		// Check processor id
+	cbz	x0, init_bss		// Hang for all non-primary CPU
+
+	wfe
+
+	b	master
+
+init_bss:
+	adr	x0, __bss_start
+	adr	x1, __bss_end
+	sub	x1, x1, x0
+	bl	memzero
+
+    b move_to_el1
+
+move_to_el1:
+	ldr	x0, =SCTLR_VALUE_MMU_DISABLED
+	msr	sctlr_el1, x0
+
+	ldr	x0, =HCR_VALUE
+	msr	hcr_el2, x0
+
+	ldr	x0, =SPSR_VALUE
+	msr	spsr_el2, x0
+
+	adr	x0, master
+	msr	elr_el2, x0
+
+	eret
+
+master:
+	mrs	x0, mpidr_el1
+	and	x0, x0, #0xFF
+	mov	x1, #SECTION_SIZE
+	mul	x1, x1, x0
+	add	x1, x1, #LOW_MEMORY
+	mov	sp, x1
+
+	bl	kernel_main
+
+proc_hang:
+	b	proc_hang
+
diff --git a/bulb/src/kernel/kernel.c b/bulb/src/kernel/kernel.c
new file mode 100644
index 0000000..d4cc08b
--- /dev/null
+++ b/bulb/src/kernel/kernel.c
@@ -0,0 +1,43 @@
+#include "common/font.h"
+#include "common/gpu.h"
+#include "common/logging.h"
+#include "common/printf.h"
+#include "common/status_led.h"
+#include "common/utils.h"
+#include "kernel/mm.h"
+#include "kernel/mmu.h"
+
+void hang (int led, int cycles) {
+    while (1) {
+        toggle_led (led);
+        delay (cycles);
+    }
+}
+
+void kernel_init (void) {
+    set_led (0, POWER_LED);
+    set_led (0, STATUS_LED);
+
+    if (init_gpu ()) {
+        if (get_fb ()) {
+            font_set_normal ();
+            init_printf (0, putc_screen);
+            printf ("Frame  buffer:     %p\r\n", get_fb ());
+            printf ("Width  resolution: %d\r\n", get_fb_info ()->virtual_width);
+            printf ("Height resolution: %d\r\n", get_fb_info ()->virtual_height);
+
+            LOG ("Initialisation done");
+            ERROR ("I'm important!");
+        } else
+            hang (POWER_LED, 1000000);
+    } else
+        hang (POWER_LED, 2000000);
+}
+
+void kernel_main (int processor_id) {
+    kernel_init ();
+
+    printf ("Hello, from processor %d in EL %d\r\n", processor_id, get_el ());
+
+    hang (STATUS_LED, 5000000);
+}
diff --git a/bulb/src/kernel/mailbox.c b/bulb/src/kernel/mailbox.c
new file mode 100644
index 0000000..a744c50
--- /dev/null
+++ b/bulb/src/kernel/mailbox.c
@@ -0,0 +1,52 @@
+#include "kernel/mailbox.h"
+
+bool mailbox_request (volatile unsigned int * data_ptr, channel_t channel) {
+    volatile unsigned int * buffer = data_ptr;
+
+    if (DUMP_BUFFER) {
+        LOG ("Dumping message buffer before sending:");
+        int_dump ((unsigned int *) buffer);
+        hex_dump ((byte_t *) buffer);
+    }
+
+    // 28-bit address (MSB) and 4-bit value (LSB)
+    unsigned int outgoing = ((unsigned int) ((long) data_ptr) & ~0xF) | (channel & 0xF);
+
+    // Wait until we can write
+    while (get32 (MBOX0 + MBOX_STATUS) & MBOX_WRITE_FULL)
+        ;
+
+    // Write the address of our buffer to the mailbox with the channel appended
+    put32 (MBOX0 + MBOX_WRITE, outgoing);
+
+    unsigned int incoming;
+    while (1) {
+        // Is there a reply?
+        while (get32 (MBOX0 + MBOX_STATUS) & MBOX_READ_EMPTY)
+            ;
+
+        incoming = get32 (MBOX0 + MBOX_READ);
+
+        // Is it a reply to our message?
+        if (outgoing == incoming) {
+            if (buffer[1] != MBOX_SUCCESS) {
+                if (DUMP_BUFFER) {
+                    LOG ("Dumping failed message buffer:");
+                    int_dump ((unsigned int *) buffer);
+                    hex_dump ((byte_t *) buffer);
+                }
+
+                return false;
+            }
+            break;
+        }
+    }
+
+    if (DUMP_BUFFER) {
+        LOG ("Dumping successful message buffer:");
+        int_dump ((unsigned int *) buffer);
+        hex_dump ((byte_t *) buffer);
+    }
+
+    return true;
+}
diff --git a/bulb/src/kernel/mm.S b/bulb/src/kernel/mm.S
new file mode 100644
index 0000000..92e5692
--- /dev/null
+++ b/bulb/src/kernel/mm.S
@@ -0,0 +1,14 @@
+.globl memcpy
+memcpy:
+	ldr x3, [x1], #8
+	str x3, [x0], #8
+	subs x2, x2, #8
+	b.gt memcpy
+	ret
+
+.globl memzero
+memzero:
+	str xzr, [x0], #8
+	subs x1, x1, #8
+	b.gt memzero
+	ret
diff --git a/bulb/src/kernel/mm.c b/bulb/src/kernel/mm.c
new file mode 100644
index 0000000..f4da23c
--- /dev/null
+++ b/bulb/src/kernel/mm.c
@@ -0,0 +1,19 @@
+#include "kernel/mm.h"
+
+static unsigned short mem_map[PAGING_PAGES] = {
+        0,
+};
+
+ptr_t get_free_page () {
+    for (int i = 0; i < PAGING_PAGES; i++) {
+        if (mem_map[i] == 0) {
+            mem_map[i] = 1;
+            return LOW_MEMORY + i * PAGE_SIZE;
+        }
+    }
+    return 0;
+}
+
+void free_page (ptr_t p) {
+    mem_map[(p - LOW_MEMORY) / PAGE_SIZE] = 0;
+}
diff --git a/bulb/src/kernel/mmu.c b/bulb/src/kernel/mmu.c
new file mode 100644
index 0000000..f675d98
--- /dev/null
+++ b/bulb/src/kernel/mmu.c
@@ -0,0 +1,134 @@
+#include "kernel/mmu.h"
+
+void init_mmu () {
+    unsigned long data_page = (unsigned long) &_data / PAGESIZE;
+    unsigned long r, b, *paging = (unsigned long *) &_end;
+
+    /* create MMU translation tables at _end */
+
+    // TTBR0, identity L1
+    paging[0] = (unsigned long) ((unsigned char *) &_end + 2 * PAGESIZE) |// physical address
+                PT_PAGE |                                                 // it has the "Present" flag, which must be set, and we have area in it mapped by pages
+                PT_AF |                                                   // accessed flag. Without this we're going to have a Data Abort exception
+                PT_USER |                                                 // non-privileged
+                PT_ISH |                                                  // inner shareable
+                PT_MEM;                                                   // normal memory
+
+    // identity L2, first 2M block
+    paging[2 * 512] = (unsigned long) ((unsigned char *) &_end + 3 * PAGESIZE) |// physical address
+                      PT_PAGE |                                                 // we have area in it mapped by pages
+                      PT_AF |                                                   // accessed flag
+                      PT_USER |                                                 // non-privileged
+                      PT_ISH |                                                  // inner shareable
+                      PT_MEM;                                                   // normal memory
+
+    // identity L2 2M blocks
+    b = PBASE >> 21;
+    // skip 0th, as we're about to map it by L3
+    for (r = 1; r < 512; r++)
+        paging[2 * 512 + r] = (unsigned long) ((r << 21)) |                // physical address
+                              PT_BLOCK |                                   // map 2M block
+                              PT_AF |                                      // accessed flag
+                              PT_NX |                                      // no execute
+                              PT_USER |                                    // non-privileged
+                              (r >= b ? PT_OSH | PT_DEV : PT_ISH | PT_MEM);// different attributes for device memory
+
+    // identity L3
+    for (r = 0; r < 512; r++)
+        paging[3 * 512 + r] = (unsigned long) (r * PAGESIZE) |                       // physical address
+                              PT_PAGE |                                              // map 4k
+                              PT_AF |                                                // accessed flag
+                              PT_USER |                                              // non-privileged
+                              PT_ISH |                                               // inner shareable
+                              ((r < 0x80 || r >= data_page) ? PT_RW | PT_NX : PT_RO);// different for code and data
+
+    // TTBR1, kernel L1
+    paging[512 + 511] = (unsigned long) ((unsigned char *) &_end + 4 * PAGESIZE) |// physical address
+                        PT_PAGE |                                                 // we have area in it mapped by pages
+                        PT_AF |                                                   // accessed flag
+                        PT_KERNEL |                                               // privileged
+                        PT_ISH |                                                  // inner shareable
+                        PT_MEM;                                                   // normal memory
+
+    // kernel L2
+    paging[4 * 512 + 511] = (unsigned long) ((unsigned char *) &_end + 5 * PAGESIZE) |// physical address
+                            PT_PAGE |                                                 // we have area in it mapped by pages
+                            PT_AF |                                                   // accessed flag
+                            PT_KERNEL |                                               // privileged
+                            PT_ISH |                                                  // inner shareable
+                            PT_MEM;                                                   // normal memory
+
+    // kernel L3
+    paging[5 * 512] = (unsigned long) (PBASE + 0x00201000) |// physical address
+                      PT_PAGE |                             // map 4k
+                      PT_AF |                               // accessed flag
+                      PT_NX |                               // no execute
+                      PT_KERNEL |                           // privileged
+                      PT_OSH |                              // outter shareable
+                      PT_DEV;                               // device memory
+
+    /* okay, now we have to set system registers to enable MMU */
+
+    // check for 4k granule and at least 36 bits physical address bus */
+    asm volatile("mrs %0, id_aa64mmfr0_el1"
+                 : "=r"(r));
+    b = r & 0xF;
+    if (r & (0xF << 28) /*4k*/ || b < 1 /*36 bits*/) {
+        ERROR ("ERROR: 4k granule or 36 bit address space not supported\n");
+        return;
+    }
+
+    // first, set Memory Attributes array, indexed by PT_MEM, PT_DEV, PT_NC in our example
+    r = (0xFF << 0) |// AttrIdx=0: normal, IWBWA, OWBWA, NTR
+        (0x04 << 8) |// AttrIdx=1: device, nGnRE (must be OSH too)
+        (0x44 << 16);// AttrIdx=2: non cacheable
+    asm volatile("msr mair_el1, %0"
+                 :
+                 : "r"(r));
+
+    // next, specify mapping characteristics in translate control register
+    r = (0b00LL << 37) |// TBI=0, no tagging
+        (b << 32) |     // IPS=autodetected
+        (0b10LL << 30) |// TG1=4k
+        (0b11LL << 28) |// SH1=3 inner
+        (0b01LL << 26) |// ORGN1=1 write back
+        (0b01LL << 24) |// IRGN1=1 write back
+        (0b0LL << 23) | // EPD1 enable higher half
+        (25LL << 16) |  // T1SZ=25, 3 levels (512G)
+        (0b00LL << 14) |// TG0=4k
+        (0b11LL << 12) |// SH0=3 inner
+        (0b01LL << 10) |// ORGN0=1 write back
+        (0b01LL << 8) | // IRGN0=1 write back
+        (0b0LL << 7) |  // EPD0 enable lower half
+        (25LL << 0);    // T0SZ=25, 3 levels (512G)
+    asm volatile("msr tcr_el1, %0; isb"
+                 :
+                 : "r"(r));
+
+    // tell the MMU where our translation tables are. TTBR_CNP bit not documented, but required
+    // lower half, user space
+    asm volatile("msr ttbr0_el1, %0"
+                 :
+                 : "r"((unsigned long) &_end + TTBR_CNP));
+    // upper half, kernel space
+    asm volatile("msr ttbr1_el1, %0"
+                 :
+                 : "r"((unsigned long) &_end + TTBR_CNP + PAGESIZE));
+
+    // finally, toggle some bits in system control register to enable page translation
+    asm volatile("dsb ish; isb; mrs %0, sctlr_el1"
+                 : "=r"(r));
+    r |= 0xC00800;    // set mandatory reserved bits
+    r &= ~((1 << 25) |// clear EE, little endian translation tables
+           (1 << 24) |// clear E0E
+           (1 << 19) |// clear WXN
+           (1 << 12) |// clear I, no instruction cache
+           (1 << 4) | // clear SA0
+           (1 << 3) | // clear SA
+           (1 << 2) | // clear C, no cache at all
+           (1 << 1)); // clear A, no aligment check
+    r |= (1 << 0);    // set M, enable MMU
+    asm volatile("msr sctlr_el1, %0; isb"
+                 :
+                 : "r"(r));
+}
\ No newline at end of file
diff --git a/bulb/src/linker.ld b/bulb/src/linker.ld
new file mode 100644
index 0000000..332bfc8
--- /dev/null
+++ b/bulb/src/linker.ld
@@ -0,0 +1,19 @@
+SECTIONS
+{
+    . = 0x80000;
+	.text.boot : { *(.text.boot) }
+	.text : { *(.text) }
+	.rodata : { *(.rodata) }
+    PROVIDE(_data = .);
+	.data : { *(.data) }
+	.bss (NOLOAD) : {
+        . = ALIGN(16);
+        __bss_start = .;
+        *(.bss .bss.*)
+        *(COMMON)
+        __bss_end = .;
+    }
+    . = ALIGN(4096);
+    _end = .;
+}
+__bss_size = (__bss_end - __bss_start) >> 3;
\ No newline at end of file

From 8efba797d1815567ef22c9f7c860daf3a1ba129b Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Tue, 2 Nov 2021 13:02:13 +0100
Subject: [PATCH 02/21] chore(mmu): add logging to mmu init

---
 bulb/include/kernel/mmu.h |  1 +
 bulb/src/kernel/kernel.c  |  2 ++
 bulb/src/kernel/mmu.c     | 13 +++++++++++++
 3 files changed, 16 insertions(+)

diff --git a/bulb/include/kernel/mmu.h b/bulb/include/kernel/mmu.h
index 3db2fbe..e72bea5 100644
--- a/bulb/include/kernel/mmu.h
+++ b/bulb/include/kernel/mmu.h
@@ -5,6 +5,7 @@
 // https://github.com/bztsrc/raspi3-tutorial/blob/master/10_virtualmemory/mmu.c
 
 #include "common/logging.h"
+#include "common/status_led.h"
 #include "kernel/peripherals/base.h"
 
 #define PAGESIZE 4096
diff --git a/bulb/src/kernel/kernel.c b/bulb/src/kernel/kernel.c
index d4cc08b..ab7eac3 100644
--- a/bulb/src/kernel/kernel.c
+++ b/bulb/src/kernel/kernel.c
@@ -37,6 +37,8 @@ void kernel_init (void) {
 void kernel_main (int processor_id) {
     kernel_init ();
 
+    init_mmu ();
+
     printf ("Hello, from processor %d in EL %d\r\n", processor_id, get_el ());
 
     hang (STATUS_LED, 5000000);
diff --git a/bulb/src/kernel/mmu.c b/bulb/src/kernel/mmu.c
index f675d98..62fbfea 100644
--- a/bulb/src/kernel/mmu.c
+++ b/bulb/src/kernel/mmu.c
@@ -68,6 +68,7 @@ void init_mmu () {
                       PT_DEV;                               // device memory
 
     /* okay, now we have to set system registers to enable MMU */
+    //    hang (POWER_LED, 2000000);
 
     // check for 4k granule and at least 36 bits physical address bus */
     asm volatile("mrs %0, id_aa64mmfr0_el1"
@@ -85,6 +86,7 @@ void init_mmu () {
     asm volatile("msr mair_el1, %0"
                  :
                  : "r"(r));
+    LOG ("MAIR attributes written");
 
     // next, specify mapping characteristics in translate control register
     r = (0b00LL << 37) |// TBI=0, no tagging
@@ -105,15 +107,20 @@ void init_mmu () {
                  :
                  : "r"(r));
 
+    LOG ("Translation control register written");
+
     // tell the MMU where our translation tables are. TTBR_CNP bit not documented, but required
     // lower half, user space
     asm volatile("msr ttbr0_el1, %0"
                  :
                  : "r"((unsigned long) &_end + TTBR_CNP));
+    LOG ("TTBR0 written");
+
     // upper half, kernel space
     asm volatile("msr ttbr1_el1, %0"
                  :
                  : "r"((unsigned long) &_end + TTBR_CNP + PAGESIZE));
+    LOG ("TTBR1 written");
 
     // finally, toggle some bits in system control register to enable page translation
     asm volatile("dsb ish; isb; mrs %0, sctlr_el1"
@@ -128,7 +135,13 @@ void init_mmu () {
            (1 << 2) | // clear C, no cache at all
            (1 << 1)); // clear A, no aligment check
     r |= (1 << 0);    // set M, enable MMU
+
+    LOG ("Read out system control register");
+
     asm volatile("msr sctlr_el1, %0; isb"
                  :
                  : "r"(r));
+
+    LOG ("Modify and write back system control register flags");
+    return;
 }
\ No newline at end of file

From 20e271c38a29b4bc3fd93a7f14e71c7f0a901e61 Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Tue, 2 Nov 2021 14:01:18 +0100
Subject: [PATCH 03/21] chore(mmu): add some debugging...

---
 bulb/include/common/font.h |  6 ++++++
 bulb/include/kernel/mmu.h  |  6 ++++++
 bulb/src/common/font.c     |  8 ++++++++
 bulb/src/kernel/mmu.c      | 15 ++++++++++++---
 4 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/bulb/include/common/font.h b/bulb/include/common/font.h
index 5b49ada..b732416 100644
--- a/bulb/include/common/font.h
+++ b/bulb/include/common/font.h
@@ -13,8 +13,14 @@
 #define FONT_TAB_SIZE       4
 #define FONT_TAB_REAL_WIDTH (FONT_TAB_SIZE * FONT_REAL_WIDTH)
 
+// If this is defined, scrollback is used
+#define FONT_SCROLLBACK
+// Scroll by this amount at the same time. High = fast, low = fancy
+#define FONT_SB_LINES 1
+
 #include "common/gpu.h"
 #include "common/screen.h"
+#include "kernel/mm.h"
 
 static point_t cursor = {0, 0};
 
diff --git a/bulb/include/kernel/mmu.h b/bulb/include/kernel/mmu.h
index e72bea5..471bb20 100644
--- a/bulb/include/kernel/mmu.h
+++ b/bulb/include/kernel/mmu.h
@@ -36,4 +36,10 @@ extern volatile unsigned char _end;
 
 void init_mmu (void);
 
+static char msg[] = "tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt889898ttttttttttttttttttttttttttttttttttttttttttttttttt908ttttttttttttttttttttttttttttttttttttttt+-"
+                    "tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt889898ttttttttttttttttttttttttttttttttttttttttttttttttt908ttttttttttttttttttttttttttttttttttttttt+-"
+                    "tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt889898ttttttttttttttttttttttttttttttttttttttttttttttttt908ttttttttttttttttttttttttttttttttttttttt+-"
+                    "tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt889898ttttttttttttttttttttttttttttttttttttttttttttttttt908ttttttttttttttttttttttttttttttttttttttt+-"
+                    "tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt889898ttttttttttttttttttttttttttttttttttttttttttttttttt908ttttttttttttttttttttttttttttttt########+-";
+
 #endif//_ROSE_MMU_H
\ No newline at end of file
diff --git a/bulb/src/common/font.c b/bulb/src/common/font.c
index ca66890..8e61da3 100644
--- a/bulb/src/common/font.c
+++ b/bulb/src/common/font.c
@@ -178,8 +178,16 @@ void printc (char c) {
     }
     // If next line would overflow screen height (ignoring line spacing) move to beginning of screen
     if (cursor.y + FONT_REAL_WIDTH - FONT_SPACING >= get_max_height ()) {
+#ifndef FONT_SCROLLBACK
+        cursor.y -= FONT_SB_LINES * FONT_REAL_HEIGHT;
+        unsigned int remove_size = FONT_SB_LINES * FONT_REAL_HEIGHT * get_fb_info ()->pitch;
+        unsigned int scroll_size = get_fb_info ()->fb_size - remove_size;
+        memcpy ((ptr_t) get_fb (), (ptr_t) get_fb () + remove_size, scroll_size);
+        memzero ((ptr_t) get_fb () + scroll_size, remove_size);
+#else
         // TODO clear framebuffer here...?
         cursor.y = 0;
+#endif
     }
 }
 
diff --git a/bulb/src/kernel/mmu.c b/bulb/src/kernel/mmu.c
index 62fbfea..03a6afc 100644
--- a/bulb/src/kernel/mmu.c
+++ b/bulb/src/kernel/mmu.c
@@ -78,6 +78,7 @@ void init_mmu () {
         ERROR ("ERROR: 4k granule or 36 bit address space not supported\n");
         return;
     }
+    LOG ("4k granule and 36bit address bus ensured");
 
     // first, set Memory Attributes array, indexed by PT_MEM, PT_DEV, PT_NC in our example
     r = (0xFF << 0) |// AttrIdx=0: normal, IWBWA, OWBWA, NTR
@@ -106,7 +107,6 @@ void init_mmu () {
     asm volatile("msr tcr_el1, %0; isb"
                  :
                  : "r"(r));
-
     LOG ("Translation control register written");
 
     // tell the MMU where our translation tables are. TTBR_CNP bit not documented, but required
@@ -142,6 +142,15 @@ void init_mmu () {
                  :
                  : "r"(r));
 
-    LOG ("Modify and write back system control register flags");
-    return;
+    LOG ("Set SCTLR flags and enable MMU");
+
+    while (1) {
+        printc ('.');
+    }
+    //    printf (msg);
+    //    printf ("test");
+
+    set_led (POWER_LED, 1);
+
+    hang (STATUS_LED, 2000000);
 }
\ No newline at end of file

From 48523398e9d765168c78df3c9fb2a1c530c0b76d Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Wed, 3 Nov 2021 11:51:05 +0100
Subject: [PATCH 04/21] feat(bulb): add irq to show MMU calls sync invalid
 exception

---
 bulb/include/kernel/arm/sysregs.h           |   6 +-
 bulb/include/kernel/irq.h                   |  23 +++
 bulb/include/kernel/mini_uart.h             |  33 ++++
 bulb/include/kernel/mmu.h                   |  10 +-
 bulb/include/kernel/peripherals/irq.h       |  37 ++++
 bulb/include/kernel/peripherals/mini_uart.h |  25 +++
 bulb/src/kernel/entry.S                     | 181 ++++++++++++++++++++
 bulb/src/kernel/irq.S                       |  15 ++
 bulb/src/kernel/irq.c                       |  55 ++++++
 bulb/src/kernel/kernel.c                    |  16 ++
 bulb/src/kernel/mini_uart.c                 |  88 ++++++++++
 bulb/src/kernel/mmu.c                       |  46 +++--
 12 files changed, 518 insertions(+), 17 deletions(-)
 create mode 100644 bulb/include/kernel/irq.h
 create mode 100644 bulb/include/kernel/mini_uart.h
 create mode 100644 bulb/include/kernel/peripherals/irq.h
 create mode 100644 bulb/include/kernel/peripherals/mini_uart.h
 create mode 100644 bulb/src/kernel/entry.S
 create mode 100644 bulb/src/kernel/irq.S
 create mode 100644 bulb/src/kernel/irq.c
 create mode 100644 bulb/src/kernel/mini_uart.c

diff --git a/bulb/include/kernel/arm/sysregs.h b/bulb/include/kernel/arm/sysregs.h
index 98acd8b..ccdda11 100644
--- a/bulb/include/kernel/arm/sysregs.h
+++ b/bulb/include/kernel/arm/sysregs.h
@@ -43,7 +43,9 @@
 // ESR_EL1, Exception Syndrome Register (EL1). Page 2431 of AArch64-Reference-Manual.
 // ***************************************
 
-#define ESR_ELx_EC_SHIFT 26
-#define ESR_ELx_EC_SVC64 0x15
+#define ESR_ELx_EC_SHIFT     26
+#define ESR_ELx_EC_SVC64     0x15
+#define ESR_ELx_EC_DABT_LOW  0b100100
+#define ESR_ELx_EC_DABT_SAME 0b100101
 
 #endif /*_ROSE_K_A_SYSREGS_H*/
diff --git a/bulb/include/kernel/irq.h b/bulb/include/kernel/irq.h
new file mode 100644
index 0000000..9221696
--- /dev/null
+++ b/bulb/include/kernel/irq.h
@@ -0,0 +1,23 @@
+#ifndef _ROSE_K_IRQ_H
+#define _ROSE_K_IRQ_H
+
+#include "common/printf.h"
+#include "common/stddef.h"
+#include "common/utils.h"
+#include "kernel/arm/sysregs.h"
+#include "kernel/entry.h"
+#include "kernel/peripherals/irq.h"
+
+#include "kernel/mini_uart.h"
+
+void enable_interrupt_controller (void);
+
+void show_invalid_entry_message (int type, ptr_t esr, ptr_t address);
+
+void irq_vector_init (void);
+
+void enable_irq (void);
+
+void disable_irq (void);
+
+#endif /*_ROSE_K_IRQ_H */
diff --git a/bulb/include/kernel/mini_uart.h b/bulb/include/kernel/mini_uart.h
new file mode 100644
index 0000000..46499cf
--- /dev/null
+++ b/bulb/include/kernel/mini_uart.h
@@ -0,0 +1,33 @@
+#ifndef _ROSE_K_UART_H
+#ifndef _ROSE_K_MINI_UART_H
+#define _ROSE_K_MINI_UART_H
+
+#include "common/gpu.h"
+#include "common/stdbool.h"
+#include "common/utils.h"
+#include "kernel/peripherals/gpio.h"
+#include "kernel/peripherals/mini_uart.h"
+//#include "kernel/power.h"
+
+void mini_uart_init (void);
+
+char mini_uart_recv (void);
+
+void mini_uart_send (char c);
+
+void mini_uart_send_string (char * str);
+
+void handle_mini_uart_irq (void);
+
+// This function is required by printf function
+void mini_putc (void * p, char c);
+
+#define uart_init        mini_uart_init
+#define uart_recv        mini_uart_recv
+#define uart_send        mini_uart_send
+#define uart_send_string mini_uart_send_string
+
+#define putc mini_putc
+
+#endif /*_ROSE_K_MINI_UART_H */
+#endif /*_ROSE_K_UART_H */
diff --git a/bulb/include/kernel/mmu.h b/bulb/include/kernel/mmu.h
index 471bb20..ffa6200 100644
--- a/bulb/include/kernel/mmu.h
+++ b/bulb/include/kernel/mmu.h
@@ -1,9 +1,12 @@
 #ifndef _ROSE_MMU_H
 #define _ROSE_MMU_H
 
+#ifndef __ASSEMBLER__
+
 // Implementation taken from
 // https://github.com/bztsrc/raspi3-tutorial/blob/master/10_virtualmemory/mmu.c
 
+#include "common/font.h"
 #include "common/logging.h"
 #include "common/status_led.h"
 #include "kernel/peripherals/base.h"
@@ -36,10 +39,7 @@ extern volatile unsigned char _end;
 
 void init_mmu (void);
 
-static char msg[] = "tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt889898ttttttttttttttttttttttttttttttttttttttttttttttttt908ttttttttttttttttttttttttttttttttttttttt+-"
-                    "tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt889898ttttttttttttttttttttttttttttttttttttttttttttttttt908ttttttttttttttttttttttttttttttttttttttt+-"
-                    "tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt889898ttttttttttttttttttttttttttttttttttttttttttttttttt908ttttttttttttttttttttttttttttttttttttttt+-"
-                    "tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt889898ttttttttttttttttttttttttttttttttttttttttttttttttt908ttttttttttttttttttttttttttttttttttttttt+-"
-                    "tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt889898ttttttttttttttttttttttttttttttttttttttttttttttttt908ttttttttttttttttttttttttttttttt########+-";
+void data_abort_el1 (ptr_t far, ptr_t esr);
 
+#endif
 #endif//_ROSE_MMU_H
\ No newline at end of file
diff --git a/bulb/include/kernel/peripherals/irq.h b/bulb/include/kernel/peripherals/irq.h
new file mode 100644
index 0000000..9900292
--- /dev/null
+++ b/bulb/include/kernel/peripherals/irq.h
@@ -0,0 +1,37 @@
+#ifndef _ROSE_K_P_IRQ_H
+#define _ROSE_K_P_IRQ_H
+
+#include "kernel/peripherals/base.h"
+
+#define GIC_BASE       0xFF840000
+#define GICD_DIST_BASE (GIC_BASE + 0x00001000)
+#define GICC_CPU_BASE  (GIC_BASE + 0x00002000)
+
+#define GICD_ENABLE_IRQ_BASE (GICD_DIST_BASE + 0x00000100)
+
+#define GICC_IAR  (GICC_CPU_BASE + 0x0000000C)
+#define GICC_EOIR (GICC_CPU_BASE + 0x00000010)
+
+#define GIC_IRQ_TARGET_BASE (GICD_DIST_BASE + 0x00000800)
+
+//VC (=VideoCore) starts at 96
+#define SYSTEM_TIMER_IRQ_0 (0x60)//96
+#define SYSTEM_TIMER_IRQ_1 (0x61)//97
+#define SYSTEM_TIMER_IRQ_2 (0x62)//98
+#define SYSTEM_TIMER_IRQ_3 (0x63)//99
+
+#define IRQ_BASIC_PENDING  (PBASE + 0x0000B200)
+#define IRQ_PENDING_1      (PBASE + 0x0000B204)
+#define IRQ_PENDING_2      (PBASE + 0x0000B208)
+#define FIQ_CONTROL        (PBASE + 0x0000B20C)
+#define ENABLE_IRQS_1      (PBASE + 0x0000B210)
+#define ENABLE_IRQS_2      (PBASE + 0x0000B214)
+#define ENABLE_BASIC_IRQS  (PBASE + 0x0000B218)
+#define DISABLE_IRQS_1     (PBASE + 0x0000B21C)
+#define DISABLE_IRQS_2     (PBASE + 0x0000B220)
+#define DISABLE_BASIC_IRQS (PBASE + 0x0000B224)
+
+#define MINI_UART_IRQ  (1 << 0)
+#define ENABLE_AUX_INT (1 << 29)
+
+#endif /*_ROSE_K_P_IRQ_H */
diff --git a/bulb/include/kernel/peripherals/mini_uart.h b/bulb/include/kernel/peripherals/mini_uart.h
new file mode 100644
index 0000000..b065deb
--- /dev/null
+++ b/bulb/include/kernel/peripherals/mini_uart.h
@@ -0,0 +1,25 @@
+#ifndef _ROSE_K_P_MINI_UART_H
+#define _ROSE_K_P_MINI_UART_H
+
+#include "base.h"
+
+#define SYSTEM_CLOCK_FREQ              500000000
+#define BAUD_RATE_REG(target_baudrate) ((SYSTEM_CLOCK_FREQ / target_baudrate / 8) - 1)
+
+#define AUX_IRQ_REG     (PBASE + 0x00215000)
+#define AUX_ENABLES     (PBASE + 0x00215004)
+#define AUX_MU_IO_REG   (PBASE + 0x00215040)
+#define AUX_MU_IER_REG  (PBASE + 0x00215044)
+#define AUX_MU_IIR_REG  (PBASE + 0x00215048)
+#define AUX_MU_LCR_REG  (PBASE + 0x0021504C)
+#define AUX_MU_MCR_REG  (PBASE + 0x00215050)
+#define AUX_MU_LSR_REG  (PBASE + 0x00215054)
+#define AUX_MU_MSR_REG  (PBASE + 0x00215058)
+#define AUX_MU_SCRATCH  (PBASE + 0x0021505C)
+#define AUX_MU_CNTL_REG (PBASE + 0x00215060)
+#define AUX_MU_STAT_REG (PBASE + 0x00215064)
+#define AUX_MU_BAUD_REG (PBASE + 0x00215068)
+
+#define ENABLE_MU_REC_INT (0xFD)
+
+#endif /*_ROSE_K_P_MINI_UART_H */
diff --git a/bulb/src/kernel/entry.S b/bulb/src/kernel/entry.S
new file mode 100644
index 0000000..604b0af
--- /dev/null
+++ b/bulb/src/kernel/entry.S
@@ -0,0 +1,181 @@
+#include "kernel/arm/sysregs.h"
+#include "kernel/entry.h"
+#include "kernel/mmu.h"
+
+	.macro handle_invalid_entry el, type
+	kernel_entry \el
+	mov	x0, #\type
+	mrs	x1, esr_el1
+	mrs	x2, elr_el1
+	bl	show_invalid_entry_message
+	b	err_hang
+	.endm
+
+	.macro	ventry	label
+	.align	7
+	b	\label
+	.endm
+
+	.macro	kernel_entry, el
+	sub	sp, sp, #S_FRAME_SIZE
+	stp	x0, x1, [sp, #16 * 0]
+	stp	x2, x3, [sp, #16 * 1]
+	stp	x4, x5, [sp, #16 * 2]
+	stp	x6, x7, [sp, #16 * 3]
+	stp	x8, x9, [sp, #16 * 4]
+	stp	x10, x11, [sp, #16 * 5]
+	stp	x12, x13, [sp, #16 * 6]
+	stp	x14, x15, [sp, #16 * 7]
+	stp	x16, x17, [sp, #16 * 8]
+	stp	x18, x19, [sp, #16 * 9]
+	stp	x20, x21, [sp, #16 * 10]
+	stp	x22, x23, [sp, #16 * 11]
+	stp	x24, x25, [sp, #16 * 12]
+	stp	x26, x27, [sp, #16 * 13]
+	stp	x28, x29, [sp, #16 * 14]
+
+	.if	\el == 0
+	mrs	x21, sp_el0
+	.else
+	add	x21, sp, #S_FRAME_SIZE
+	.endif /* \el == 0 */
+
+	mrs	x22, elr_el1
+	mrs	x23, spsr_el1
+
+	stp	x30, x21, [sp, #16 * 15]
+	stp	x22, x23, [sp, #16 * 16]
+	.endm
+
+	.macro	kernel_exit, el
+	ldp	x22, x23, [sp, #16 * 16]
+	ldp	x30, x21, [sp, #16 * 15]
+
+	.if	\el == 0
+	msr	sp_el0, x21
+	.endif /* \el == 0 */
+
+	msr	elr_el1, x22
+	msr	spsr_el1, x23
+
+
+	ldp	x0, x1, [sp, #16 * 0]
+	ldp	x2, x3, [sp, #16 * 1]
+	ldp	x4, x5, [sp, #16 * 2]
+	ldp	x6, x7, [sp, #16 * 3]
+	ldp	x8, x9, [sp, #16 * 4]
+	ldp	x10, x11, [sp, #16 * 5]
+	ldp	x12, x13, [sp, #16 * 6]
+	ldp	x14, x15, [sp, #16 * 7]
+	ldp	x16, x17, [sp, #16 * 8]
+	ldp	x18, x19, [sp, #16 * 9]
+	ldp	x20, x21, [sp, #16 * 10]
+	ldp	x22, x23, [sp, #16 * 11]
+	ldp	x24, x25, [sp, #16 * 12]
+	ldp	x26, x27, [sp, #16 * 13]
+	ldp	x28, x29, [sp, #16 * 14]
+	add	sp, sp, #S_FRAME_SIZE
+	eret
+	.endm
+
+
+/*
+ * Exception vectors.
+ */
+.align	11
+.globl vectors
+vectors:
+	ventry	sync_invalid_el1t			// Synchronous EL1t
+	ventry	irq_invalid_el1t			// IRQ EL1t
+	ventry	fiq_invalid_el1t			// FIQ EL1t
+	ventry	error_invalid_el1t			// Error EL1t
+
+	ventry	sync_invalid_el1h			// Synchronous EL1h
+	ventry	el1_irq					// IRQ EL1h
+	ventry	fiq_invalid_el1h			// FIQ EL1h
+	ventry	error_invalid_el1h			// Error EL1h
+
+	ventry	el0_sync				// Synchronous 64-bit EL0
+	ventry	el0_irq					// IRQ 64-bit EL0
+	ventry	fiq_invalid_el0_64			// FIQ 64-bit EL0
+	ventry	error_invalid_el0_64			// Error 64-bit EL0
+
+	ventry	sync_invalid_el0_32			// Synchronous 32-bit EL0
+	ventry	irq_invalid_el0_32			// IRQ 32-bit EL0
+	ventry	fiq_invalid_el0_32			// FIQ 32-bit EL0
+	ventry	error_invalid_el0_32			// Error 32-bit EL0
+
+sync_invalid_el1t:
+	handle_invalid_entry 1,  SYNC_INVALID_EL1t
+
+irq_invalid_el1t:
+	handle_invalid_entry  1, IRQ_INVALID_EL1t
+
+fiq_invalid_el1t:
+	handle_invalid_entry  1, FIQ_INVALID_EL1t
+
+error_invalid_el1t:
+	handle_invalid_entry  1, ERROR_INVALID_EL1t
+
+sync_invalid_el1h:
+	handle_invalid_entry 1, SYNC_INVALID_EL1h
+
+fiq_invalid_el1h:
+	handle_invalid_entry  1, FIQ_INVALID_EL1h
+
+error_invalid_el1h:
+	handle_invalid_entry  1, ERROR_INVALID_EL1h
+
+fiq_invalid_el0_64:
+	handle_invalid_entry  0, FIQ_INVALID_EL0_64
+
+error_invalid_el0_64:
+	handle_invalid_entry  0, ERROR_INVALID_EL0_64
+
+sync_invalid_el0_32:
+	handle_invalid_entry  0, SYNC_INVALID_EL0_32
+
+irq_invalid_el0_32:
+	handle_invalid_entry  0, IRQ_INVALID_EL0_32
+
+fiq_invalid_el0_32:
+	handle_invalid_entry  0, FIQ_INVALID_EL0_32
+
+error_invalid_el0_32:
+	handle_invalid_entry  0, ERROR_INVALID_EL0_32
+
+el1_irq:
+	kernel_entry 1
+	bl	handle_irq
+	kernel_exit 1
+
+el0_irq:
+	kernel_entry 0
+	bl	handle_irq
+	kernel_exit 0
+
+el0_sync:
+	kernel_entry 0
+
+    mrs	x25, esr_el1
+	lsr	x24, x25, #ESR_ELx_EC_SHIFT
+	cmp x24, #ESR_ELx_EC_DABT_SAME
+	b.eq 	el1_da
+
+	handle_invalid_entry 0, SYNC_ERROR
+
+sc_nr	.req	x25					// number of system calls
+scno	.req	x26					// syscall number
+stbl	.req	x27					// syscall table pointer
+
+el1_da:
+	bl enable_irq
+	mrs x0, far_el1
+	mrs x1, esr_el1
+	bl data_abort_el1
+    bl disable_irq
+    eret
+
+.globl err_hang
+err_hang: b err_hang
+
diff --git a/bulb/src/kernel/irq.S b/bulb/src/kernel/irq.S
new file mode 100644
index 0000000..ad54157
--- /dev/null
+++ b/bulb/src/kernel/irq.S
@@ -0,0 +1,15 @@
+.globl irq_vector_init
+irq_vector_init:
+	adr	x0, vectors		// load VBAR_EL1 with virtual
+	msr	vbar_el1, x0		// vector table address
+	ret
+
+.globl enable_irq
+enable_irq:
+	msr    daifclr, #2
+	ret
+
+.globl disable_irq
+disable_irq:
+	msr	daifset, #2
+	ret
diff --git a/bulb/src/kernel/irq.c b/bulb/src/kernel/irq.c
new file mode 100644
index 0000000..491ee73
--- /dev/null
+++ b/bulb/src/kernel/irq.c
@@ -0,0 +1,55 @@
+#include "kernel/irq.h"
+
+const char * entry_error_messages[] = {
+        "SYNC_INVALID_EL1t", "IRQ_INVALID_EL1t", "FIQ_INVALID_EL1t", "ERROR_INVALID_EL1T", "SYNC_INVALID_EL1h", "IRQ_INVALID_EL1h", "FIQ_INVALID_EL1h", "ERROR_INVALID_EL1h", "SYNC_INVALID_EL0_64", "IRQ_INVALID_EL0_64", "FIQ_INVALID_EL0_64", "ERROR_INVALID_EL0_64", "SYNC_INVALID_EL0_32", "IRQ_INVALID_EL0_32", "FIQ_INVALID_EL0_32", "ERROR_INVALID_EL0_32", "SYNC_ERROR", "SYSCALL_ERROR"};
+
+void enable_interrupt (unsigned int irq) {
+    printf ("Interrupt pointer %p\r\n", irq);
+    unsigned int n              = irq / 32;
+    unsigned int offset         = irq % 32;
+    unsigned int enableRegister = GICD_ENABLE_IRQ_BASE + (4 * n);
+    printf ("EnableRegister: %x\r\n", enableRegister);
+    put32 (enableRegister, 1 << offset);
+}
+
+void assign_target (unsigned int irq, unsigned int cpu) {
+    unsigned int n              = irq / 4;
+    unsigned int targetRegister = GIC_IRQ_TARGET_BASE + (4 * n);
+    // Currently we only enter the target CPU 0
+    put32 (targetRegister, get32 (targetRegister) | (1 << 8));
+}
+
+void show_invalid_entry_message (int type, ptr_t esr, ptr_t address) {
+    printf ("Type %s, ESR: %p, address, %p\r\n", entry_error_messages[type], (void *) esr, (void *) address);
+}
+
+void enable_interrupt_controller () {
+    assign_target (SYSTEM_TIMER_IRQ_1, 0);
+    put32 (ENABLE_IRQS_1, SYSTEM_TIMER_IRQ_1
+#ifdef _ROSE_K_MINI_UART_H
+                                  | ENABLE_AUX_INT
+#endif
+    );
+    enable_interrupt (SYSTEM_TIMER_IRQ_1);
+}
+
+void handle_irq (void) {
+    put32 (GICC_EOIR, get32 (GICC_IAR));
+    /*
+    unsigned int irq_ack_reg = get32 (GICC_IAR);
+    unsigned int irq1        = irq_ack_reg & 0x2FF;
+    if (irq1 & SYSTEM_TIMER_IRQ_1) {
+        put32 (GICC_EOIR, irq_ack_reg);
+        handle_timer_irq ();
+    }
+
+#ifdef _ROSE_K_MINI_UART_H
+    unsigned int irq2 = get32 (AUX_IRQ_REG);
+    if (irq2 & MINI_UART_IRQ) {
+        put32 (GICC_EOIR, irq_ack_reg);
+        handle_mini_uart_irq ();
+    }
+
+#endif
+     */
+}
diff --git a/bulb/src/kernel/kernel.c b/bulb/src/kernel/kernel.c
index ab7eac3..efa2772 100644
--- a/bulb/src/kernel/kernel.c
+++ b/bulb/src/kernel/kernel.c
@@ -4,6 +4,9 @@
 #include "common/printf.h"
 #include "common/status_led.h"
 #include "common/utils.h"
+//#include "kernel/mini_uart.h"
+#include "kernel/entry.h"
+#include "kernel/irq.h"
 #include "kernel/mm.h"
 #include "kernel/mmu.h"
 
@@ -14,10 +17,18 @@ void hang (int led, int cycles) {
     }
 }
 
+void dual_print (void * p, char c) {
+    printc (c);
+    //    uart_send (c);
+}
+
 void kernel_init (void) {
     set_led (0, POWER_LED);
     set_led (0, STATUS_LED);
 
+    //    uart_init ();
+    //    init_printf (0, putc);
+
     if (init_gpu ()) {
         if (get_fb ()) {
             font_set_normal ();
@@ -32,6 +43,11 @@ void kernel_init (void) {
             hang (POWER_LED, 1000000);
     } else
         hang (POWER_LED, 2000000);
+    init_printf (0, dual_print);
+
+    irq_vector_init ();
+    enable_interrupt_controller ();
+    enable_irq ();
 }
 
 void kernel_main (int processor_id) {
diff --git a/bulb/src/kernel/mini_uart.c b/bulb/src/kernel/mini_uart.c
new file mode 100644
index 0000000..92273d7
--- /dev/null
+++ b/bulb/src/kernel/mini_uart.c
@@ -0,0 +1,88 @@
+#include "kernel/mini_uart.h"
+/*
+void mini_uart_send (char c) {
+    while (1) {
+        if (get32 (AUX_MU_LSR_REG) & 0x20) {
+            break;
+        }
+    }
+    put32 (AUX_MU_IO_REG, c);
+}
+
+char mini_uart_recv (void) {
+    while (1) {
+        if (get32 (AUX_MU_LSR_REG) & 0x01) {
+            break;
+        }
+    }
+    return (get32 (AUX_MU_IO_REG) & 0xFF);
+}
+
+void mini_uart_send_string (char * str) {
+    for (int i = 0; str[i] != '\0'; i++) {
+        mini_uart_send ((char) str[i]);
+    }
+}
+
+void mini_uart_init (void) {
+    static volatile bool init_progress = false;
+    static volatile bool init_done     = false;
+
+    if (init_progress) {
+        while (!init_done)
+            ;
+        return;
+    }
+    init_progress = true;
+
+    unsigned int selector;
+    int          target = BAUD_RATE_REG (115200);
+
+    selector = get32 (GPFSEL1);
+    selector &= ~(7 << 12);
+    selector |= 2 << 12;
+    selector &= ~(7 << 15);
+    selector |= 2 << 15;
+    put32 (GPFSEL1, selector);
+
+    put32 (GPPUD, 0);
+    delay (150);
+    put32 (GPPUDCLK0, (1 << 14) | (1 << 15));
+    delay (150);
+    put32 (GPPUDCLK0, 0);
+
+    put32 (AUX_ENABLES, 1);
+    put32 (AUX_MU_CNTL_REG, 0);
+    put32 (AUX_MU_IER_REG, ENABLE_MU_REC_INT);
+    put32 (AUX_MU_LCR_REG, 3);
+    put32 (AUX_MU_MCR_REG, 0);
+    put32 (AUX_MU_BAUD_REG, target);
+
+    put32 (AUX_MU_CNTL_REG, 3);
+
+    mini_uart_send_string ("\033[2J\033[H");
+    mini_uart_send_string ("Initialised mini UART\r\n");
+
+    init_done = true;
+}
+
+//void handle_mini_uart_irq (void) {
+//    char c_event = mini_uart_recv ();
+//    switch (c_event) {
+//                    case 17:// device control 1
+//                        mini_uart_send_string ("Power off");
+//                        poweroff (40, true);// power off instantly, never return control here
+//                    case 18:                // device control 2
+//                        mini_uart_send_string ("Reboot");
+//                        reboot (40, true);// reboot instantly, never return control here
+//        case 19:
+//            toggle_blank_screen ();
+//        default:
+//            mini_uart_send (c_event);
+//    }
+//}
+
+void mini_putc (void * p, char c) {
+    mini_uart_send (c);
+}
+ */
\ No newline at end of file
diff --git a/bulb/src/kernel/mmu.c b/bulb/src/kernel/mmu.c
index 03a6afc..6c7ae07 100644
--- a/bulb/src/kernel/mmu.c
+++ b/bulb/src/kernel/mmu.c
@@ -60,7 +60,7 @@ void init_mmu () {
 
     // kernel L3
     paging[5 * 512] = (unsigned long) (PBASE + 0x00201000) |// physical address
-                      PT_PAGE |                             // map 4k
+                      PT_BLOCK |                            // map 4k
                       PT_AF |                               // accessed flag
                       PT_NX |                               // no execute
                       PT_KERNEL |                           // privileged
@@ -68,8 +68,6 @@ void init_mmu () {
                       PT_DEV;                               // device memory
 
     /* okay, now we have to set system registers to enable MMU */
-    //    hang (POWER_LED, 2000000);
-
     // check for 4k granule and at least 36 bits physical address bus */
     asm volatile("mrs %0, id_aa64mmfr0_el1"
                  : "=r"(r));
@@ -142,15 +140,43 @@ void init_mmu () {
                  :
                  : "r"(r));
 
-    LOG ("Set SCTLR flags and enable MMU");
+    //    LOG ("Set SCTLR flags and enable MMU");
+    //    printf ("Printing non-aborting data: %d\r\n", *(char *) 0x000000001234abcd);
+    printf ((char *) 0xFFFF000000080000);
 
-    while (1) {
-        printc ('.');
-    }
-    //    printf (msg);
-    //    printf ("test");
 
     set_led (POWER_LED, 1);
 
-    hang (STATUS_LED, 2000000);
+    while (1) {
+        toggle_led (STATUS_LED);
+        delay (1000000);
+    }
+}
+
+void data_abort_el1 (ptr_t far, ptr_t esr) {
+    byte_t type  = (esr >> 2) & 0b11;
+    byte_t level = esr & 0b11;
+    //    esr &= 0b111111;
+
+    printf ("EL 1 - ");
+    printf ("FAR_EL1: %p - ", far);
+    printf ("ESR_EL1: %b\n\r", esr);
+
+    switch (type) {
+        case 0b00:// Address size fault
+            printf ("Address size fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            //            exit_process ();
+            break;
+        case 0b01:// Translation fault
+            printf ("Translation fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            break;
+        case 0b10:// Access flag fault
+            printf ("Access flag fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            //            exit_process ();
+            break;
+        case 0b11:// Permission fault
+            printf ("Segmentation fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            //            exit_process ();
+            break;
+    }
 }
\ No newline at end of file

From 8342385c446d40674cfce2f5ea2de2357ef8d1ce Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Wed, 3 Nov 2021 13:28:34 +0100
Subject: [PATCH 05/21] refactor(mmu): initialise PGD0 tables for kernel

---
 bulb/include/kernel/mmu.h |   3 +
 bulb/src/kernel/mmu.c     | 149 ++++++++++++++++++++++++--------------
 2 files changed, 97 insertions(+), 55 deletions(-)

diff --git a/bulb/include/kernel/mmu.h b/bulb/include/kernel/mmu.h
index ffa6200..a7fb810 100644
--- a/bulb/include/kernel/mmu.h
+++ b/bulb/include/kernel/mmu.h
@@ -37,6 +37,9 @@
 extern volatile unsigned char _data;
 extern volatile unsigned char _end;
 
+static volatile unsigned int __attribute__ ((aligned (16))) buffer[32];
+
+void init_pages (unsigned long * r, unsigned long * b);
 void init_mmu (void);
 
 void data_abort_el1 (ptr_t far, ptr_t esr);
diff --git a/bulb/src/kernel/mmu.c b/bulb/src/kernel/mmu.c
index 6c7ae07..07bf9a7 100644
--- a/bulb/src/kernel/mmu.c
+++ b/bulb/src/kernel/mmu.c
@@ -1,71 +1,107 @@
 #include "kernel/mmu.h"
 
-void init_mmu () {
-    unsigned long data_page = (unsigned long) &_data / PAGESIZE;
-    unsigned long r, b, *paging = (unsigned long *) &_end;
+static volatile unsigned int buffer[] = {32, 0, 0x00038041, 8, 0, 42, 1, 0};
 
-    /* create MMU translation tables at _end */
+void init_pages (unsigned long * r, unsigned long * b) {
+    unsigned long   data_page = (unsigned long) &_data / PAGESIZE;
+    unsigned long * paging    = (unsigned long *) &_end;
+
+    //    unsigned long * PGD0 = paging + 0 * 512;
+    //    unsigned long * PGD1 = paging + 1 * 512;
+    unsigned long * PUD0 = paging + 0 * 512;
+    unsigned long * PUD1 = paging + 1 * 512;
+    unsigned long * PMD0 = paging + 2 * 512;
+    unsigned long * PMD1 = paging + 4 * 512;
+    unsigned long * PTE0 = paging + 3 * 512;
+    unsigned long * PTE1 = paging + 5 * 512;
 
+    /* create MMU translation tables at _end */
     // TTBR0, identity L1
-    paging[0] = (unsigned long) ((unsigned char *) &_end + 2 * PAGESIZE) |// physical address
-                PT_PAGE |                                                 // it has the "Present" flag, which must be set, and we have area in it mapped by pages
-                PT_AF |                                                   // accessed flag. Without this we're going to have a Data Abort exception
-                PT_USER |                                                 // non-privileged
-                PT_ISH |                                                  // inner shareable
-                PT_MEM;                                                   // normal memory
+    PUD0[0] = (unsigned long) ((unsigned char *) &_end + 2 * PAGESIZE) |// physical address
+              PT_PAGE |                                                 // it has the "Present" flag, which must be set, and we have area in it mapped by pages
+              PT_AF |                                                   // accessed flag. Without this we're going to have a Data Abort exception
+              PT_USER |                                                 // non-privileged
+              PT_ISH |                                                  // inner shareable
+              PT_MEM;                                                   // normal memory
 
     // identity L2, first 2M block
-    paging[2 * 512] = (unsigned long) ((unsigned char *) &_end + 3 * PAGESIZE) |// physical address
-                      PT_PAGE |                                                 // we have area in it mapped by pages
-                      PT_AF |                                                   // accessed flag
-                      PT_USER |                                                 // non-privileged
-                      PT_ISH |                                                  // inner shareable
-                      PT_MEM;                                                   // normal memory
+    PMD0[0] = (unsigned long) ((unsigned char *) &_end + 3 * PAGESIZE) |// physical address
+              PT_PAGE |                                                 // we have area in it mapped by pages
+              PT_AF |                                                   // accessed flag
+              PT_USER |                                                 // non-privileged
+              PT_ISH |                                                  // inner shareable
+              PT_MEM;                                                   // normal memory
 
     // identity L2 2M blocks
-    b = PBASE >> 21;
+    *b = PBASE >> 21;
     // skip 0th, as we're about to map it by L3
-    for (r = 1; r < 512; r++)
-        paging[2 * 512 + r] = (unsigned long) ((r << 21)) |                // physical address
-                              PT_BLOCK |                                   // map 2M block
-                              PT_AF |                                      // accessed flag
-                              PT_NX |                                      // no execute
-                              PT_USER |                                    // non-privileged
-                              (r >= b ? PT_OSH | PT_DEV : PT_ISH | PT_MEM);// different attributes for device memory
+    for (*r = 1; *r < 512; (*r)++)
+        PMD0[*r] = (unsigned long) (((*r) << 21)) |               // physical address
+                   PT_BLOCK |                                     // map 2M block
+                   PT_AF |                                        // accessed flag
+                   PT_NX |                                        // no execute
+                   PT_USER |                                      // non-privileged
+                   (*r >= *b ? PT_OSH | PT_DEV : PT_ISH | PT_MEM);// different attributes for device memory
 
     // identity L3
-    for (r = 0; r < 512; r++)
-        paging[3 * 512 + r] = (unsigned long) (r * PAGESIZE) |                       // physical address
-                              PT_PAGE |                                              // map 4k
-                              PT_AF |                                                // accessed flag
-                              PT_USER |                                              // non-privileged
-                              PT_ISH |                                               // inner shareable
-                              ((r < 0x80 || r >= data_page) ? PT_RW | PT_NX : PT_RO);// different for code and data
-
+    for (*r = 0; *r < 512; (*r)++)
+        PTE0[*r] = (unsigned long) (*r * PAGESIZE) |                        // physical address
+                   PT_PAGE |                                                // map 4k
+                   PT_AF |                                                  // accessed flag
+                   PT_USER |                                                // non-privileged
+                   PT_ISH |                                                 // inner shareable
+                   ((*r < 0x80 || *r >= data_page) ? PT_RW | PT_NX : PT_RO);// different for code and data
+
+    /*
     // TTBR1, kernel L1
-    paging[512 + 511] = (unsigned long) ((unsigned char *) &_end + 4 * PAGESIZE) |// physical address
-                        PT_PAGE |                                                 // we have area in it mapped by pages
-                        PT_AF |                                                   // accessed flag
-                        PT_KERNEL |                                               // privileged
-                        PT_ISH |                                                  // inner shareable
-                        PT_MEM;                                                   // normal memory
+    PUD1[0] = (unsigned long) ((unsigned char *) &_end + 4 * PAGESIZE) |// physical address
+              PT_PAGE |                                                 // we have area in it mapped by pages
+              PT_AF |                                                   // accessed flag
+              PT_KERNEL |                                               // privileged
+              PT_ISH |                                                  // inner shareable
+              PT_MEM;                                                   // normal memory
 
     // kernel L2
-    paging[4 * 512 + 511] = (unsigned long) ((unsigned char *) &_end + 5 * PAGESIZE) |// physical address
-                            PT_PAGE |                                                 // we have area in it mapped by pages
-                            PT_AF |                                                   // accessed flag
-                            PT_KERNEL |                                               // privileged
-                            PT_ISH |                                                  // inner shareable
-                            PT_MEM;                                                   // normal memory
+    PMD1[0] = (unsigned long) ((unsigned char *) &_end + 5 * PAGESIZE) |// physical address
+              PT_PAGE |                                                 // we have area in it mapped by pages
+              PT_AF |                                                   // accessed flag
+              PT_KERNEL |                                               // privileged
+              PT_ISH |                                                  // inner shareable
+              PT_MEM;                                                   // normal memory
+
+    // kernel L2
+    PMD1[511] = (unsigned long) ((unsigned char *) &_end + 5 * PAGESIZE) |// physical address
+                PT_PAGE |                                                 // we have area in it mapped by pages
+                PT_AF |                                                   // accessed flag
+                PT_KERNEL |                                               // privileged
+                PT_ISH |                                                  // inner shareable
+                PT_MEM;                                                   // normal memory
+
+    // kernel L3
+    PTE1[0] = (unsigned long) (PBASE + 0x00201000) |// physical address
+              PT_PAGE |                             // map 4k
+              PT_AF |                               // accessed flag
+              PT_NX |                               // no execute
+              PT_KERNEL |                           // privileged
+              PT_OSH |                              // outter shareable
+              PT_DEV;                               // device memory
 
     // kernel L3
-    paging[5 * 512] = (unsigned long) (PBASE + 0x00201000) |// physical address
-                      PT_BLOCK |                            // map 4k
-                      PT_AF |                               // accessed flag
-                      PT_NX |                               // no execute
-                      PT_KERNEL |                           // privileged
-                      PT_OSH |                              // outter shareable
-                      PT_DEV;                               // device memory
+    PTE1[511] = (unsigned long) (PBASE + 0x00201000) |// physical address
+                PT_PAGE |                             // map 4k
+                PT_AF |                               // accessed flag
+                PT_NX |                               // no execute
+                PT_KERNEL |                           // privileged
+                PT_OSH |                              // outter shareable
+                PT_DEV;                               // device memory
+    */
+}
+
+void init_mmu () {
+    unsigned long data_page = (unsigned long) &_data / PAGESIZE;
+    unsigned long r, b, *paging = (unsigned long *) &_end;
+
+    init_pages (&r, &b);
 
     /* okay, now we have to set system registers to enable MMU */
     // check for 4k granule and at least 36 bits physical address bus */
@@ -117,7 +153,7 @@ void init_mmu () {
     // upper half, kernel space
     asm volatile("msr ttbr1_el1, %0"
                  :
-                 : "r"((unsigned long) &_end + TTBR_CNP + PAGESIZE));
+                 : "r"((unsigned long) &_end + TTBR_CNP));
     LOG ("TTBR1 written");
 
     // finally, toggle some bits in system control register to enable page translation
@@ -140,10 +176,13 @@ void init_mmu () {
                  :
                  : "r"(r));
 
-    //    LOG ("Set SCTLR flags and enable MMU");
-    //    printf ("Printing non-aborting data: %d\r\n", *(char *) 0x000000001234abcd);
-    printf ((char *) 0xFFFF000000080000);
+    LOG ("Set SCTLR flags and enable MMU");
+    *((unsigned int volatile *) (0xFE00B8A0));
+    LOG ("LED SWITCHING DONE");
+
+    delay (100);
 
+    LOG ("TEST");
 
     set_led (POWER_LED, 1);
 

From 447dbd47b23a138453845f3df2e2d8d8e815de47 Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Wed, 3 Nov 2021 15:27:59 +0100
Subject: [PATCH 06/21] fix(mmu): correctly initialise tables, esp. peripheral
 base

Printing + manual switching of LEDs works now
---
 bulb/include/common/font.h |   2 +-
 bulb/src/kernel/entry.S    |  12 ++--
 bulb/src/kernel/mmu.c      | 126 +++++++++++++------------------------
 3 files changed, 50 insertions(+), 90 deletions(-)

diff --git a/bulb/include/common/font.h b/bulb/include/common/font.h
index b732416..0791dde 100644
--- a/bulb/include/common/font.h
+++ b/bulb/include/common/font.h
@@ -2,7 +2,7 @@
 #define _ROSE_C_FONT_H
 
 #define FONT_SIZE       8
-#define FONT_FACTOR     2
+#define FONT_FACTOR     4
 #define FONT_REAL_WIDTH (FONT_SIZE * FONT_FACTOR)
 
 // Spacing between lines in pixels
diff --git a/bulb/src/kernel/entry.S b/bulb/src/kernel/entry.S
index 604b0af..7198926 100644
--- a/bulb/src/kernel/entry.S
+++ b/bulb/src/kernel/entry.S
@@ -90,20 +90,20 @@ vectors:
 	ventry	fiq_invalid_el1t			// FIQ EL1t
 	ventry	error_invalid_el1t			// Error EL1t
 
-	ventry	sync_invalid_el1h			// Synchronous EL1h
-	ventry	el1_irq					// IRQ EL1h
+    ventry	sync_invalid_el1h			// Synchronous EL1h
+	ventry	el1_irq					    // IRQ EL1h
 	ventry	fiq_invalid_el1h			// FIQ EL1h
 	ventry	error_invalid_el1h			// Error EL1h
 
-	ventry	el0_sync				// Synchronous 64-bit EL0
-	ventry	el0_irq					// IRQ 64-bit EL0
+	ventry	el0_sync				    // Synchronous 64-bit EL0
+	ventry	el0_irq					    // IRQ 64-bit EL0
 	ventry	fiq_invalid_el0_64			// FIQ 64-bit EL0
-	ventry	error_invalid_el0_64			// Error 64-bit EL0
+	ventry	error_invalid_el0_64		// Error 64-bit EL0
 
 	ventry	sync_invalid_el0_32			// Synchronous 32-bit EL0
 	ventry	irq_invalid_el0_32			// IRQ 32-bit EL0
 	ventry	fiq_invalid_el0_32			// FIQ 32-bit EL0
-	ventry	error_invalid_el0_32			// Error 32-bit EL0
+	ventry	error_invalid_el0_32		// Error 32-bit EL0
 
 sync_invalid_el1t:
 	handle_invalid_entry 1,  SYNC_INVALID_EL1t
diff --git a/bulb/src/kernel/mmu.c b/bulb/src/kernel/mmu.c
index 07bf9a7..0508c4f 100644
--- a/bulb/src/kernel/mmu.c
+++ b/bulb/src/kernel/mmu.c
@@ -6,95 +6,47 @@ void init_pages (unsigned long * r, unsigned long * b) {
     unsigned long   data_page = (unsigned long) &_data / PAGESIZE;
     unsigned long * paging    = (unsigned long *) &_end;
 
-    //    unsigned long * PGD0 = paging + 0 * 512;
-    //    unsigned long * PGD1 = paging + 1 * 512;
     unsigned long * PUD0 = paging + 0 * 512;
-    unsigned long * PUD1 = paging + 1 * 512;
     unsigned long * PMD0 = paging + 2 * 512;
-    unsigned long * PMD1 = paging + 4 * 512;
-    unsigned long * PTE0 = paging + 3 * 512;
-    unsigned long * PTE1 = paging + 5 * 512;
+    unsigned long * PTE0 = paging + 1 * 512;
 
     /* create MMU translation tables at _end */
     // TTBR0, identity L1
-    PUD0[0] = (unsigned long) ((unsigned char *) &_end + 2 * PAGESIZE) |// physical address
-              PT_PAGE |                                                 // it has the "Present" flag, which must be set, and we have area in it mapped by pages
-              PT_AF |                                                   // accessed flag. Without this we're going to have a Data Abort exception
-              PT_USER |                                                 // non-privileged
-              PT_ISH |                                                  // inner shareable
-              PT_MEM;                                                   // normal memory
+    *b = PBASE >> 21;
+    for (int i = 0; i < 8; i++) {
+        PUD0[i] = (unsigned long) ((unsigned char *) &_end + (2 + i) * PAGESIZE) |// physical address
+                  PT_PAGE |                                                       // it has the "Present" flag, which must be set, and we have area in it mapped by pages
+                  PT_AF |                                                         // accessed flag. Without this we're going to have a Data Abort exception
+                  PT_USER |                                                       // non-privileged
+                  PT_ISH |                                                        // inner shareable
+                  PT_MEM;                                                         // normal memory
+
+        unsigned int offset = i * 512;
+        // identity L2 2M blocks
+        for (*r = 0; *r < 512; (*r)++)
+            PMD0[i * 512 + *r] = (unsigned long) ((offset + *r) << 21) |                 // physical address
+                                 PT_BLOCK |                                              // map 2M block
+                                 PT_AF |                                                 // accessed flag
+                                 PT_USER |                                               // non-privileged
+                                 (offset + *r >= *b ? PT_OSH | PT_DEV : PT_ISH | PT_MEM);// different attributes for device memory
+    }
 
     // identity L2, first 2M block
-    PMD0[0] = (unsigned long) ((unsigned char *) &_end + 3 * PAGESIZE) |// physical address
-              PT_PAGE |                                                 // we have area in it mapped by pages
-              PT_AF |                                                   // accessed flag
-              PT_USER |                                                 // non-privileged
-              PT_ISH |                                                  // inner shareable
-              PT_MEM;                                                   // normal memory
-
-    // identity L2 2M blocks
-    *b = PBASE >> 21;
-    // skip 0th, as we're about to map it by L3
-    for (*r = 1; *r < 512; (*r)++)
-        PMD0[*r] = (unsigned long) (((*r) << 21)) |               // physical address
-                   PT_BLOCK |                                     // map 2M block
-                   PT_AF |                                        // accessed flag
-                   PT_NX |                                        // no execute
-                   PT_USER |                                      // non-privileged
-                   (*r >= *b ? PT_OSH | PT_DEV : PT_ISH | PT_MEM);// different attributes for device memory
+    PMD0[0] = (unsigned long) ((unsigned char *) &_end + PAGESIZE) |// physical address
+              PT_PAGE |                                             // we have area in it mapped by pages
+              PT_AF |                                               // accessed flag
+              PT_USER |                                             // non-privileged
+              PT_ISH |                                              // inner shareable
+              PT_MEM;                                               // normal memory
 
     // identity L3
     for (*r = 0; *r < 512; (*r)++)
-        PTE0[*r] = (unsigned long) (*r * PAGESIZE) |                        // physical address
-                   PT_PAGE |                                                // map 4k
-                   PT_AF |                                                  // accessed flag
-                   PT_USER |                                                // non-privileged
-                   PT_ISH |                                                 // inner shareable
-                   ((*r < 0x80 || *r >= data_page) ? PT_RW | PT_NX : PT_RO);// different for code and data
-
-    /*
-    // TTBR1, kernel L1
-    PUD1[0] = (unsigned long) ((unsigned char *) &_end + 4 * PAGESIZE) |// physical address
-              PT_PAGE |                                                 // we have area in it mapped by pages
-              PT_AF |                                                   // accessed flag
-              PT_KERNEL |                                               // privileged
-              PT_ISH |                                                  // inner shareable
-              PT_MEM;                                                   // normal memory
-
-    // kernel L2
-    PMD1[0] = (unsigned long) ((unsigned char *) &_end + 5 * PAGESIZE) |// physical address
-              PT_PAGE |                                                 // we have area in it mapped by pages
-              PT_AF |                                                   // accessed flag
-              PT_KERNEL |                                               // privileged
-              PT_ISH |                                                  // inner shareable
-              PT_MEM;                                                   // normal memory
-
-    // kernel L2
-    PMD1[511] = (unsigned long) ((unsigned char *) &_end + 5 * PAGESIZE) |// physical address
-                PT_PAGE |                                                 // we have area in it mapped by pages
-                PT_AF |                                                   // accessed flag
-                PT_KERNEL |                                               // privileged
-                PT_ISH |                                                  // inner shareable
-                PT_MEM;                                                   // normal memory
-
-    // kernel L3
-    PTE1[0] = (unsigned long) (PBASE + 0x00201000) |// physical address
-              PT_PAGE |                             // map 4k
-              PT_AF |                               // accessed flag
-              PT_NX |                               // no execute
-              PT_KERNEL |                           // privileged
-              PT_OSH |                              // outter shareable
-              PT_DEV;                               // device memory
-
-    // kernel L3
-    PTE1[511] = (unsigned long) (PBASE + 0x00201000) |// physical address
-                PT_PAGE |                             // map 4k
-                PT_AF |                               // accessed flag
-                PT_NX |                               // no execute
-                PT_KERNEL |                           // privileged
-                PT_OSH |                              // outter shareable
-                PT_DEV;                               // device memory
-    */
+        PTE0[*r] = (unsigned long) (*r * PAGESIZE) |                // physical address
+                   PT_PAGE |                                        // map 4k
+                   PT_AF |                                          // accessed flag
+                   PT_USER |                                        // non-privileged
+                   PT_ISH |                                         // inner shareable
+                   ((*r < 0x80 || *r >= data_page) ? PT_RW : PT_RO);// different for code and data
 }
 
 void init_mmu () {
@@ -171,18 +123,26 @@ void init_mmu () {
     r |= (1 << 0);    // set M, enable MMU
 
     LOG ("Read out system control register");
+    printf ("Current status LED status: %l\r\n", get_led (STATUS_LED));
 
     asm volatile("msr sctlr_el1, %0; isb"
                  :
                  : "r"(r));
 
     LOG ("Set SCTLR flags and enable MMU");
-    *((unsigned int volatile *) (0xFE00B8A0));
-    LOG ("LED SWITCHING DONE");
 
-    delay (100);
+    *((unsigned int volatile *) (0xFE00B8A0)) = (unsigned long) buffer | 8;
+    LOG ("LED SWITCHING DONE");
 
-    LOG ("TEST");
+    printf ("Msg : %p\r\n", (unsigned long) buffer | 8);
+    printf ("%u ", buffer[0]);
+    printf ("%u ", buffer[1]);
+    printf ("%p ", buffer[2]);
+    printf ("%u ", buffer[3]);
+    printf ("%u ", buffer[4]);
+    printf ("%u ", buffer[5]);
+    printf ("%u ", buffer[6]);
+    printf ("%u \r\n", buffer[7]);
 
     set_led (POWER_LED, 1);
 

From 4a930b0d7d87520bc2c0d5e365d2ed3b02522f1e Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Wed, 3 Nov 2021 15:31:24 +0100
Subject: [PATCH 07/21] refactor(mmu): removed weird passing of r and b by
 reference

---
 bulb/include/kernel/mmu.h |  4 +++-
 bulb/src/kernel/mmu.c     | 38 +++++++++++++++++++-------------------
 2 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/bulb/include/kernel/mmu.h b/bulb/include/kernel/mmu.h
index a7fb810..408f210 100644
--- a/bulb/include/kernel/mmu.h
+++ b/bulb/include/kernel/mmu.h
@@ -33,13 +33,15 @@
 
 #define TTBR_CNP 1
 
+#define RAM_IN_GB 8
+
 // get addresses from linker
 extern volatile unsigned char _data;
 extern volatile unsigned char _end;
 
 static volatile unsigned int __attribute__ ((aligned (16))) buffer[32];
 
-void init_pages (unsigned long * r, unsigned long * b);
+void init_pages ();
 void init_mmu (void);
 
 void data_abort_el1 (ptr_t far, ptr_t esr);
diff --git a/bulb/src/kernel/mmu.c b/bulb/src/kernel/mmu.c
index 0508c4f..8945481 100644
--- a/bulb/src/kernel/mmu.c
+++ b/bulb/src/kernel/mmu.c
@@ -2,9 +2,9 @@
 
 static volatile unsigned int buffer[] = {32, 0, 0x00038041, 8, 0, 42, 1, 0};
 
-void init_pages (unsigned long * r, unsigned long * b) {
-    unsigned long   data_page = (unsigned long) &_data / PAGESIZE;
-    unsigned long * paging    = (unsigned long *) &_end;
+void init_pages () {
+    unsigned long data_page = (unsigned long) &_data / PAGESIZE;
+    unsigned long r, b, *paging = (unsigned long *) &_end;
 
     unsigned long * PUD0 = paging + 0 * 512;
     unsigned long * PMD0 = paging + 2 * 512;
@@ -12,8 +12,8 @@ void init_pages (unsigned long * r, unsigned long * b) {
 
     /* create MMU translation tables at _end */
     // TTBR0, identity L1
-    *b = PBASE >> 21;
-    for (int i = 0; i < 8; i++) {
+    b = PBASE >> 21;
+    for (int i = 0; i < RAM_IN_GB; i++) {
         PUD0[i] = (unsigned long) ((unsigned char *) &_end + (2 + i) * PAGESIZE) |// physical address
                   PT_PAGE |                                                       // it has the "Present" flag, which must be set, and we have area in it mapped by pages
                   PT_AF |                                                         // accessed flag. Without this we're going to have a Data Abort exception
@@ -23,12 +23,12 @@ void init_pages (unsigned long * r, unsigned long * b) {
 
         unsigned int offset = i * 512;
         // identity L2 2M blocks
-        for (*r = 0; *r < 512; (*r)++)
-            PMD0[i * 512 + *r] = (unsigned long) ((offset + *r) << 21) |                 // physical address
-                                 PT_BLOCK |                                              // map 2M block
-                                 PT_AF |                                                 // accessed flag
-                                 PT_USER |                                               // non-privileged
-                                 (offset + *r >= *b ? PT_OSH | PT_DEV : PT_ISH | PT_MEM);// different attributes for device memory
+        for (r = 0; r < 512; r++)
+            PMD0[i * 512 + r] = (unsigned long) ((offset + r) << 21) |                // physical address
+                                PT_BLOCK |                                            // map 2M block
+                                PT_AF |                                               // accessed flag
+                                PT_USER |                                             // non-privileged
+                                (offset + r >= b ? PT_OSH | PT_DEV : PT_ISH | PT_MEM);// different attributes for device memory
     }
 
     // identity L2, first 2M block
@@ -40,20 +40,20 @@ void init_pages (unsigned long * r, unsigned long * b) {
               PT_MEM;                                               // normal memory
 
     // identity L3
-    for (*r = 0; *r < 512; (*r)++)
-        PTE0[*r] = (unsigned long) (*r * PAGESIZE) |                // physical address
-                   PT_PAGE |                                        // map 4k
-                   PT_AF |                                          // accessed flag
-                   PT_USER |                                        // non-privileged
-                   PT_ISH |                                         // inner shareable
-                   ((*r < 0x80 || *r >= data_page) ? PT_RW : PT_RO);// different for code and data
+    for (r = 0; r < 512; r++)
+        PTE0[r] = (unsigned long) (r * PAGESIZE) |               // physical address
+                  PT_PAGE |                                      // map 4k
+                  PT_AF |                                        // accessed flag
+                  PT_USER |                                      // non-privileged
+                  PT_ISH |                                       // inner shareable
+                  ((r < 0x80 || r >= data_page) ? PT_RW : PT_RO);// different for code and data
 }
 
 void init_mmu () {
     unsigned long data_page = (unsigned long) &_data / PAGESIZE;
     unsigned long r, b, *paging = (unsigned long *) &_end;
 
-    init_pages (&r, &b);
+    init_pages ();
 
     /* okay, now we have to set system registers to enable MMU */
     // check for 4k granule and at least 36 bits physical address bus */

From c68ec3759a851963e2a5799a06a6c8e87a64c518 Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Wed, 3 Nov 2021 16:10:45 +0100
Subject: [PATCH 08/21] feat(bulb): enable (timer, uart) interrupts

---
 bulb/include/kernel/mmu.h               |  1 +
 bulb/include/kernel/peripherals/power.h | 21 +++++++++++++++
 bulb/include/kernel/peripherals/timer.h | 19 ++++++++++++++
 bulb/include/kernel/power.h             | 14 ++++++++++
 bulb/include/kernel/timer.h             |  8 ++++++
 bulb/src/kernel/entry.S                 |  2 +-
 bulb/src/kernel/irq.c                   |  4 ---
 bulb/src/kernel/kernel.c                | 13 +++++----
 bulb/src/kernel/mini_uart.c             | 35 ++++++++++++-------------
 bulb/src/kernel/mmu.c                   |  8 +-----
 bulb/src/kernel/power.c                 | 19 ++++++++++++++
 bulb/src/kernel/timer.c                 | 23 ++++++++++++++++
 12 files changed, 132 insertions(+), 35 deletions(-)
 create mode 100644 bulb/include/kernel/peripherals/power.h
 create mode 100644 bulb/include/kernel/peripherals/timer.h
 create mode 100644 bulb/include/kernel/power.h
 create mode 100644 bulb/include/kernel/timer.h
 create mode 100644 bulb/src/kernel/power.c
 create mode 100644 bulb/src/kernel/timer.c

diff --git a/bulb/include/kernel/mmu.h b/bulb/include/kernel/mmu.h
index 408f210..b9537a6 100644
--- a/bulb/include/kernel/mmu.h
+++ b/bulb/include/kernel/mmu.h
@@ -9,6 +9,7 @@
 #include "common/font.h"
 #include "common/logging.h"
 #include "common/status_led.h"
+#include "kernel/mini_uart.h"
 #include "kernel/peripherals/base.h"
 
 #define PAGESIZE 4096
diff --git a/bulb/include/kernel/peripherals/power.h b/bulb/include/kernel/peripherals/power.h
new file mode 100644
index 0000000..b02469f
--- /dev/null
+++ b/bulb/include/kernel/peripherals/power.h
@@ -0,0 +1,21 @@
+#ifndef _ROSE_K_P_POWER_H
+#define _ROSE_K_P_POWER_H
+
+#include "kernel/peripherals/base.h"
+
+#define PM_BASE PBASE + 0x100000
+
+#define PM_RSTC PM_BASE + 0x1c
+#define PM_WDOG PM_BASE + 0x24
+
+#define PM_WDOG_RESET            0000000000
+#define PM_PASSWORD              0x5a000000
+#define PM_WDOG_TIME_SET         0x000fffff
+#define PM_RSTC_WRCFG_CLR        0xffffffcf
+#define PM_RSTC_WRCFG_SET        0x00000030
+#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
+#define PM_RSTC_RESET            0x00000102
+
+#endif//_ROSE_K_P_POWER_H
+
+/* Copyright (C) 2020 Aaron Alef */
\ No newline at end of file
diff --git a/bulb/include/kernel/peripherals/timer.h b/bulb/include/kernel/peripherals/timer.h
new file mode 100644
index 0000000..ae3bf7f
--- /dev/null
+++ b/bulb/include/kernel/peripherals/timer.h
@@ -0,0 +1,19 @@
+#ifndef _ROSE_K_P_TIMER_H
+#define _ROSE_K_P_TIMER_H
+
+#include "kernel/peripherals/base.h"
+
+#define TIMER_CS  (PBASE + 0x00003000)
+#define TIMER_CLO (PBASE + 0x00003004)
+#define TIMER_CHI (PBASE + 0x00003008)
+#define TIMER_C0  (PBASE + 0x0000300C)
+#define TIMER_C1  (PBASE + 0x00003010)
+#define TIMER_C2  (PBASE + 0x00003014)
+#define TIMER_C3  (PBASE + 0x00003018)
+
+#define TIMER_CS_M0 (1 << 0)
+#define TIMER_CS_M1 (1 << 1)
+#define TIMER_CS_M2 (1 << 2)
+#define TIMER_CS_M3 (1 << 3)
+
+#endif /*_ROSE_K_P_TIMER_H */
diff --git a/bulb/include/kernel/power.h b/bulb/include/kernel/power.h
new file mode 100644
index 0000000..031db9c
--- /dev/null
+++ b/bulb/include/kernel/power.h
@@ -0,0 +1,14 @@
+#ifndef _ROSE_K_POWER_H
+#define _ROSE_K_POWER_H
+
+#include "common/stdbool.h"
+#include "common/utils.h"
+#include "kernel/peripherals/power.h"
+
+// power off (timeout / 16 in seconds?)
+void poweroff (unsigned int timeout, bool block);
+
+// reboot (timeout / 16 in seconds?)
+void reboot (unsigned int timeout, bool block);
+
+#endif//_ROSE_K_POWER_H
\ No newline at end of file
diff --git a/bulb/include/kernel/timer.h b/bulb/include/kernel/timer.h
new file mode 100644
index 0000000..f5cd0b8
--- /dev/null
+++ b/bulb/include/kernel/timer.h
@@ -0,0 +1,8 @@
+#ifndef _ROSE_K_TIMER_H
+#define _ROSE_K_TIMER_H
+
+void timer_init (void);
+
+void handle_timer_irq (void);
+
+#endif /*_ROSE_K_TIMER_H */
diff --git a/bulb/src/kernel/entry.S b/bulb/src/kernel/entry.S
index 7198926..dcbbce8 100644
--- a/bulb/src/kernel/entry.S
+++ b/bulb/src/kernel/entry.S
@@ -90,7 +90,7 @@ vectors:
 	ventry	fiq_invalid_el1t			// FIQ EL1t
 	ventry	error_invalid_el1t			// Error EL1t
 
-    ventry	sync_invalid_el1h			// Synchronous EL1h
+    ventry	el0_sync			// Synchronous EL1h
 	ventry	el1_irq					    // IRQ EL1h
 	ventry	fiq_invalid_el1h			// FIQ EL1h
 	ventry	error_invalid_el1h			// Error EL1h
diff --git a/bulb/src/kernel/irq.c b/bulb/src/kernel/irq.c
index 491ee73..7ca1047 100644
--- a/bulb/src/kernel/irq.c
+++ b/bulb/src/kernel/irq.c
@@ -34,8 +34,6 @@ void enable_interrupt_controller () {
 }
 
 void handle_irq (void) {
-    put32 (GICC_EOIR, get32 (GICC_IAR));
-    /*
     unsigned int irq_ack_reg = get32 (GICC_IAR);
     unsigned int irq1        = irq_ack_reg & 0x2FF;
     if (irq1 & SYSTEM_TIMER_IRQ_1) {
@@ -49,7 +47,5 @@ void handle_irq (void) {
         put32 (GICC_EOIR, irq_ack_reg);
         handle_mini_uart_irq ();
     }
-
 #endif
-     */
 }
diff --git a/bulb/src/kernel/kernel.c b/bulb/src/kernel/kernel.c
index efa2772..629c1a4 100644
--- a/bulb/src/kernel/kernel.c
+++ b/bulb/src/kernel/kernel.c
@@ -1,10 +1,11 @@
+#include "kernel/mini_uart.h"
+//
 #include "common/font.h"
 #include "common/gpu.h"
 #include "common/logging.h"
 #include "common/printf.h"
 #include "common/status_led.h"
 #include "common/utils.h"
-//#include "kernel/mini_uart.h"
 #include "kernel/entry.h"
 #include "kernel/irq.h"
 #include "kernel/mm.h"
@@ -19,15 +20,15 @@ void hang (int led, int cycles) {
 
 void dual_print (void * p, char c) {
     printc (c);
-    //    uart_send (c);
+    uart_send (c);
 }
 
 void kernel_init (void) {
     set_led (0, POWER_LED);
     set_led (0, STATUS_LED);
 
-    //    uart_init ();
-    //    init_printf (0, putc);
+    uart_init ();
+    init_printf (0, putc);
 
     if (init_gpu ()) {
         if (get_fb ()) {
@@ -45,6 +46,7 @@ void kernel_init (void) {
         hang (POWER_LED, 2000000);
     init_printf (0, dual_print);
 
+    timer_init ();
     irq_vector_init ();
     enable_interrupt_controller ();
     enable_irq ();
@@ -56,6 +58,7 @@ void kernel_main (int processor_id) {
     init_mmu ();
 
     printf ("Hello, from processor %d in EL %d\r\n", processor_id, get_el ());
+    uart_send ("EVERYTHING WORKS!!!\r\n");
 
-    hang (STATUS_LED, 5000000);
+    hang (POWER_LED, 5000000);
 }
diff --git a/bulb/src/kernel/mini_uart.c b/bulb/src/kernel/mini_uart.c
index 92273d7..64b005e 100644
--- a/bulb/src/kernel/mini_uart.c
+++ b/bulb/src/kernel/mini_uart.c
@@ -1,5 +1,5 @@
 #include "kernel/mini_uart.h"
-/*
+
 void mini_uart_send (char c) {
     while (1) {
         if (get32 (AUX_MU_LSR_REG) & 0x20) {
@@ -66,23 +66,22 @@ void mini_uart_init (void) {
     init_done = true;
 }
 
-//void handle_mini_uart_irq (void) {
-//    char c_event = mini_uart_recv ();
-//    switch (c_event) {
-//                    case 17:// device control 1
-//                        mini_uart_send_string ("Power off");
-//                        poweroff (40, true);// power off instantly, never return control here
-//                    case 18:                // device control 2
-//                        mini_uart_send_string ("Reboot");
-//                        reboot (40, true);// reboot instantly, never return control here
-//        case 19:
-//            toggle_blank_screen ();
-//        default:
-//            mini_uart_send (c_event);
-//    }
-//}
+void handle_mini_uart_irq (void) {
+    char c_event = mini_uart_recv ();
+    switch (c_event) {
+        case 17:// device control 1
+            mini_uart_send_string ("Power off");
+            poweroff (40, true);// power off instantly, never return control here
+        case 18:                // device control 2
+            mini_uart_send_string ("Reboot");
+            reboot (40, true);// reboot instantly, never return control here
+        case 19:
+            toggle_blank_screen ();
+        default:
+            mini_uart_send (c_event);
+    }
+}
 
 void mini_putc (void * p, char c) {
     mini_uart_send (c);
-}
- */
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/bulb/src/kernel/mmu.c b/bulb/src/kernel/mmu.c
index 8945481..1e11103 100644
--- a/bulb/src/kernel/mmu.c
+++ b/bulb/src/kernel/mmu.c
@@ -123,7 +123,6 @@ void init_mmu () {
     r |= (1 << 0);    // set M, enable MMU
 
     LOG ("Read out system control register");
-    printf ("Current status LED status: %l\r\n", get_led (STATUS_LED));
 
     asm volatile("msr sctlr_el1, %0; isb"
                  :
@@ -145,17 +144,12 @@ void init_mmu () {
     printf ("%u \r\n", buffer[7]);
 
     set_led (POWER_LED, 1);
-
-    while (1) {
-        toggle_led (STATUS_LED);
-        delay (1000000);
-    }
 }
 
 void data_abort_el1 (ptr_t far, ptr_t esr) {
     byte_t type  = (esr >> 2) & 0b11;
     byte_t level = esr & 0b11;
-    //    esr &= 0b111111;
+    esr &= 0b111111;
 
     printf ("EL 1 - ");
     printf ("FAR_EL1: %p - ", far);
diff --git a/bulb/src/kernel/power.c b/bulb/src/kernel/power.c
new file mode 100644
index 0000000..bcfbc55
--- /dev/null
+++ b/bulb/src/kernel/power.c
@@ -0,0 +1,19 @@
+#include "kernel/power.h"
+
+void poweroff (unsigned int timeout, bool block) {
+}
+
+void reboot (unsigned int timeout, bool block) {
+    unsigned int pm_rstc, pm_wdog;
+
+    /* Setup watchdog for reset */
+    pm_rstc = get32 (PM_RSTC);
+    // watchdog timer = timer clock / 16; need password (31:16) + value (11:0)
+    pm_wdog = PM_PASSWORD | (timeout & PM_WDOG_TIME_SET);
+    pm_rstc = PM_PASSWORD | (pm_rstc & PM_RSTC_WRCFG_CLR) | PM_RSTC_WRCFG_FULL_RESET;
+    put32 (PM_WDOG, pm_wdog);
+    put32 (PM_RSTC, pm_rstc);
+
+    while (block)
+        ;
+}
diff --git a/bulb/src/kernel/timer.c b/bulb/src/kernel/timer.c
new file mode 100644
index 0000000..0b3a5f6
--- /dev/null
+++ b/bulb/src/kernel/timer.c
@@ -0,0 +1,23 @@
+#include "kernel/peripherals/timer.h"
+#include "common/printf.h"
+#include "common/status_led.h"
+#include "common/utils.h"
+//#include "kernel/sched.h"
+
+const unsigned int interval = 200000;
+unsigned int       curVal   = 0;
+
+void timer_init (void) {
+    curVal = get32 (TIMER_CLO);
+    curVal += interval;
+    put32 (TIMER_C1, curVal);
+}
+
+void handle_timer_irq (void) {
+    toggle_led (STATUS_LED);
+
+    curVal += interval;
+    put32 (TIMER_C1, curVal);
+    put32 (TIMER_CS, TIMER_CS_M1);
+    //    timer_tick ();
+}

From c6f1c7f234a9bd8a29667efebfbf83c838b9a194 Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Wed, 3 Nov 2021 16:22:21 +0100
Subject: [PATCH 09/21] feat(mmu): initialise and enable mmu on thorn

---
 Makefile                   |   2 +-
 thorn/include/kernel/mmu.h |  51 ++++++++++++
 thorn/src/kernel/boot.S    |   4 +-
 thorn/src/kernel/kernel.c  |  11 ++-
 thorn/src/kernel/mmu.c     | 158 +++++++++++++++++++++++++++++++++++++
 thorn/src/linker.ld        |  17 ++--
 6 files changed, 231 insertions(+), 12 deletions(-)
 create mode 100644 thorn/include/kernel/mmu.h
 create mode 100644 thorn/src/kernel/mmu.c

diff --git a/Makefile b/Makefile
index 1ee03d7..e16cc6d 100644
--- a/Makefile
+++ b/Makefile
@@ -12,7 +12,7 @@ MNT_Darwin = /Volumes/boot
 #BOOT_PART = /dev/mmcblk0p1
 
 # Serial connection config
-SEND_DEFAULT_TARGET = bulb
+SEND_DEFAULT_TARGET = thorn
 BAUD_RATE = 115200
 SERIAL_PORT = $(SERIAL_PORT_$(HOST_OS))
 SERIAL_PORT_ALT = $(SERIAL_PORT_ALT_$(HOST_OS))
diff --git a/thorn/include/kernel/mmu.h b/thorn/include/kernel/mmu.h
new file mode 100644
index 0000000..b9537a6
--- /dev/null
+++ b/thorn/include/kernel/mmu.h
@@ -0,0 +1,51 @@
+#ifndef _ROSE_MMU_H
+#define _ROSE_MMU_H
+
+#ifndef __ASSEMBLER__
+
+// Implementation taken from
+// https://github.com/bztsrc/raspi3-tutorial/blob/master/10_virtualmemory/mmu.c
+
+#include "common/font.h"
+#include "common/logging.h"
+#include "common/status_led.h"
+#include "kernel/mini_uart.h"
+#include "kernel/peripherals/base.h"
+
+#define PAGESIZE 4096
+
+// granularity
+#define PT_PAGE   0b11// 4k granule
+#define PT_BLOCK  0b01// 2M granule
+// accessibility
+#define PT_KERNEL (0 << 6)   // privileged, supervisor EL1 access only
+#define PT_USER   (1 << 6)   // unprivileged, EL0 access allowed
+#define PT_RW     (0 << 7)   // read-write
+#define PT_RO     (1 << 7)   // read-only
+#define PT_AF     (1 << 10)  // accessed flag
+#define PT_NX     (1UL << 54)// no execute
+// shareability
+#define PT_OSH    (2 << 8)// outter shareable
+#define PT_ISH    (3 << 8)// inner shareable
+// defined in MAIR register
+#define PT_MEM    (0 << 2)// normal memory
+#define PT_DEV    (1 << 2)// device MMIO
+#define PT_NC     (2 << 2)// non-cachable
+
+#define TTBR_CNP 1
+
+#define RAM_IN_GB 8
+
+// get addresses from linker
+extern volatile unsigned char _data;
+extern volatile unsigned char _end;
+
+static volatile unsigned int __attribute__ ((aligned (16))) buffer[32];
+
+void init_pages ();
+void init_mmu (void);
+
+void data_abort_el1 (ptr_t far, ptr_t esr);
+
+#endif
+#endif//_ROSE_MMU_H
\ No newline at end of file
diff --git a/thorn/src/kernel/boot.S b/thorn/src/kernel/boot.S
index abfd307..b83930e 100644
--- a/thorn/src/kernel/boot.S
+++ b/thorn/src/kernel/boot.S
@@ -15,8 +15,8 @@ _start:
 	b	master
 
 init_bss:
-    adr	x0, bss_begin
-    adr	x1, bss_end
+    adr	x0, __bss_start
+    adr	x1, __bss_end
     sub	x1, x1, x0
     bl	memzero
 
diff --git a/thorn/src/kernel/kernel.c b/thorn/src/kernel/kernel.c
index 9e37699..ba50281 100644
--- a/thorn/src/kernel/kernel.c
+++ b/thorn/src/kernel/kernel.c
@@ -1,3 +1,5 @@
+#include "kernel/mini_uart.h"
+// KEEP THIS
 #include "common/font.h"
 #include "common/gpu.h"
 #include "common/logging.h"
@@ -8,8 +10,8 @@
 #include "common/utils.h"
 #include "kernel/fork.h"
 #include "kernel/irq.h"
-#include "kernel/mini_uart.h"
 #include "kernel/mm.h"
+#include "kernel/mmu.h"
 #include "kernel/sched.h"
 #include "kernel/sys.h"
 #include "kernel/timer.h"
@@ -88,9 +90,7 @@ void kernel_init (void) {
             printf ("Height resolution: %d\r\n", get_fb_info ()->virtual_height);
         }
     }
-
-    printf ("|...|...|...|...|\r\n");
-    printf ("|\t|\t|\t|\t|\r\n");
+    init_pages ();
 
     LOG ("Initialisation done");
     ERROR ("I'm important!");
@@ -106,6 +106,8 @@ void kernel_main (int processor_id) {
     // Synchronisation to prevent concurrent print
     while (processor_id != current_processor) {}
     printf ("Hello, from processor %d in EL %d\n\r", processor_id, get_el ());
+    init_mmu ();
+
     current_processor++;
     while (current_processor != 4) {}
 
@@ -125,6 +127,7 @@ void kernel_main (int processor_id) {
         case 2:
         case 3:
         default:
+            while (1) {}
             printf ("Undefined behaviour on processor %d\r\n", processor_id);
     }
     printf ("Processor %d going out of scope\r\n", processor_id);
diff --git a/thorn/src/kernel/mmu.c b/thorn/src/kernel/mmu.c
new file mode 100644
index 0000000..d500828
--- /dev/null
+++ b/thorn/src/kernel/mmu.c
@@ -0,0 +1,158 @@
+#include "kernel/mmu.h"
+
+static volatile unsigned int buffer[] = {32, 0, 0x00038041, 8, 0, 42, 1, 0};
+
+void init_pages () {
+    unsigned long data_page = (unsigned long) &_data / PAGESIZE;
+    unsigned long r, b, *paging = (unsigned long *) &_end;
+
+    unsigned long * PUD0 = paging + 0 * 512;
+    unsigned long * PMD0 = paging + 2 * 512;
+    unsigned long * PTE0 = paging + 1 * 512;
+
+    /* create MMU translation tables at _end */
+    // TTBR0, identity L1
+    b = PBASE >> 21;
+    for (int i = 0; i < RAM_IN_GB; i++) {
+        PUD0[i] = (unsigned long) ((unsigned char *) &_end + (2 + i) * PAGESIZE) |// physical address
+                  PT_PAGE |                                                       // it has the "Present" flag, which must be set, and we have area in it mapped by pages
+                  PT_AF |                                                         // accessed flag. Without this we're going to have a Data Abort exception
+                  PT_USER |                                                       // non-privileged
+                  PT_ISH |                                                        // inner shareable
+                  PT_MEM;                                                         // normal memory
+
+        unsigned int offset = i * 512;
+        // identity L2 2M blocks
+        for (r = 0; r < 512; r++)
+            PMD0[i * 512 + r] = (unsigned long) ((offset + r) << 21) |                // physical address
+                                PT_BLOCK |                                            // map 2M block
+                                PT_AF |                                               // accessed flag
+                                PT_USER |                                             // non-privileged
+                                (offset + r >= b ? PT_OSH | PT_DEV : PT_ISH | PT_MEM);// different attributes for device memory
+    }
+
+    // identity L2, first 2M block
+    PMD0[0] = (unsigned long) ((unsigned char *) &_end + PAGESIZE) |// physical address
+              PT_PAGE |                                             // we have area in it mapped by pages
+              PT_AF |                                               // accessed flag
+              PT_USER |                                             // non-privileged
+              PT_ISH |                                              // inner shareable
+              PT_MEM;                                               // normal memory
+
+    // identity L3
+    for (r = 0; r < 512; r++)
+        PTE0[r] = (unsigned long) (r * PAGESIZE) |               // physical address
+                  PT_PAGE |                                      // map 4k
+                  PT_AF |                                        // accessed flag
+                  PT_USER |                                      // non-privileged
+                  PT_ISH |                                       // inner shareable
+                  ((r < 0x80 || r >= data_page) ? PT_RW : PT_RO);// different for code and data
+}
+
+void init_mmu () {
+    unsigned long data_page = (unsigned long) &_data / PAGESIZE;
+    unsigned long r, b, *paging = (unsigned long *) &_end;
+
+    /* okay, now we have to set system registers to enable MMU */
+    // check for 4k granule and at least 36 bits physical address bus */
+    asm volatile("mrs %0, id_aa64mmfr0_el1"
+                 : "=r"(r));
+    b = r & 0xF;
+    if (r & (0xF << 28) /*4k*/ || b < 1 /*36 bits*/) {
+        ERROR ("ERROR: 4k granule or 36 bit address space not supported\n");
+        return;
+    }
+    LOG ("4k granule and 36bit address bus ensured");
+
+    // first, set Memory Attributes array, indexed by PT_MEM, PT_DEV, PT_NC in our example
+    r = (0xFF << 0) |// AttrIdx=0: normal, IWBWA, OWBWA, NTR
+        (0x04 << 8) |// AttrIdx=1: device, nGnRE (must be OSH too)
+        (0x44 << 16);// AttrIdx=2: non cacheable
+    asm volatile("msr mair_el1, %0"
+                 :
+                 : "r"(r));
+    LOG ("MAIR attributes written");
+
+    // next, specify mapping characteristics in translate control register
+    r = (0b00LL << 37) |// TBI=0, no tagging
+        (b << 32) |     // IPS=autodetected
+        (0b10LL << 30) |// TG1=4k
+        (0b11LL << 28) |// SH1=3 inner
+        (0b01LL << 26) |// ORGN1=1 write back
+        (0b01LL << 24) |// IRGN1=1 write back
+        (0b0LL << 23) | // EPD1 enable higher half
+        (25LL << 16) |  // T1SZ=25, 3 levels (512G)
+        (0b00LL << 14) |// TG0=4k
+        (0b11LL << 12) |// SH0=3 inner
+        (0b01LL << 10) |// ORGN0=1 write back
+        (0b01LL << 8) | // IRGN0=1 write back
+        (0b0LL << 7) |  // EPD0 enable lower half
+        (25LL << 0);    // T0SZ=25, 3 levels (512G)
+    asm volatile("msr tcr_el1, %0; isb"
+                 :
+                 : "r"(r));
+    LOG ("Translation control register written");
+
+    // tell the MMU where our translation tables are. TTBR_CNP bit not documented, but required
+    // lower half, user space
+    asm volatile("msr ttbr0_el1, %0"
+                 :
+                 : "r"((unsigned long) &_end + TTBR_CNP));
+    LOG ("TTBR0 written");
+
+    // upper half, kernel space
+    asm volatile("msr ttbr1_el1, %0"
+                 :
+                 : "r"((unsigned long) &_end + TTBR_CNP));
+    LOG ("TTBR1 written");
+
+    // finally, toggle some bits in system control register to enable page translation
+    asm volatile("dsb ish; isb; mrs %0, sctlr_el1"
+                 : "=r"(r));
+    r |= 0xC00800;    // set mandatory reserved bits
+    r &= ~((1 << 25) |// clear EE, little endian translation tables
+           (1 << 24) |// clear E0E
+           (1 << 19) |// clear WXN
+           (1 << 12) |// clear I, no instruction cache
+           (1 << 4) | // clear SA0
+           (1 << 3) | // clear SA
+           (1 << 2) | // clear C, no cache at all
+           (1 << 1)); // clear A, no aligment check
+    r |= (1 << 0);    // set M, enable MMU
+
+    LOG ("Read out system control register");
+
+    asm volatile("msr sctlr_el1, %0; isb"
+                 :
+                 : "r"(r));
+
+    LOG ("Set SCTLR flags and enable MMU");
+}
+
+void data_abort_el1 (ptr_t far, ptr_t esr) {
+    byte_t type  = (esr >> 2) & 0b11;
+    byte_t level = esr & 0b11;
+    esr &= 0b111111;
+
+    printf ("EL 1 - ");
+    printf ("FAR_EL1: %p - ", far);
+    printf ("ESR_EL1: %b\n\r", esr);
+
+    switch (type) {
+        case 0b00:// Address size fault
+            printf ("Address size fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            //            exit_process ();
+            break;
+        case 0b01:// Translation fault
+            printf ("Translation fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            break;
+        case 0b10:// Access flag fault
+            printf ("Access flag fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            //            exit_process ();
+            break;
+        case 0b11:// Permission fault
+            printf ("Segmentation fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            //            exit_process ();
+            break;
+    }
+}
\ No newline at end of file
diff --git a/thorn/src/linker.ld b/thorn/src/linker.ld
index b0868c4..69512aa 100644
--- a/thorn/src/linker.ld
+++ b/thorn/src/linker.ld
@@ -4,9 +4,16 @@ SECTIONS
 	.text.boot : { *(.text.boot) }
 	.text : { *(.text) }
 	.rodata : { *(.rodata) }
+    PROVIDE(_data = .);
 	.data : { *(.data) }
-	. = ALIGN(0x8);
-	bss_begin = .;
-	.bss : { *(.bss*) }
-	bss_end = .;
-}
\ No newline at end of file
+	.bss (NOLOAD) : {
+        . = ALIGN(16);
+        __bss_start = .;
+        *(.bss .bss.*)
+        *(COMMON)
+        __bss_end = .;
+    }
+    . = ALIGN(4096);
+    _end = .;
+}
+__bss_size = (__bss_end - __bss_start) >> 3;

From b0db69aa79abcd4d8c654a60900067e01f7d2858 Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Wed, 3 Nov 2021 16:33:09 +0100
Subject: [PATCH 10/21] feat(thorn): multiplex print to uart and screen

---
 thorn/src/kernel/kernel.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/thorn/src/kernel/kernel.c b/thorn/src/kernel/kernel.c
index ba50281..832b18a 100644
--- a/thorn/src/kernel/kernel.c
+++ b/thorn/src/kernel/kernel.c
@@ -16,6 +16,11 @@
 #include "kernel/sys.h"
 #include "kernel/timer.h"
 
+void multiplex_print (void * p, char c) {
+    printc (c);
+    uart_send (c);
+}
+
 void user_process1 (char * array) {
     char buf[2] = {0};
     while (1) {
@@ -84,7 +89,7 @@ void kernel_init (void) {
             printf ("Error: Invalid Framebuffer received\r\n");
         } else {
             font_set_normal ();
-            init_printf (0, putc_screen);
+            init_printf (0, multiplex_print);
             printf ("Frame  buffer:     %p\r\n", get_fb ());
             printf ("Width  resolution: %d\r\n", get_fb_info ()->virtual_width);
             printf ("Height resolution: %d\r\n", get_fb_info ()->virtual_height);

From 6ac7e1b30148c5160abada14a82813bc8b05a1a8 Mon Sep 17 00:00:00 2001
From: Max Streitberger <max.streitberger@gmail.com>
Date: Thu, 4 Nov 2021 12:03:31 +0100
Subject: [PATCH 11/21] feat(mmu): fix data abort el0

---
 thorn/include/kernel/arm/sysregs.h |  6 +++--
 thorn/include/kernel/mmu.h         |  2 +-
 thorn/src/common/printf.c          | 13 ++++++++++
 thorn/src/kernel/entry.S           | 39 +++++++++++++++++++-----------
 thorn/src/kernel/mmu.c             | 12 ++++-----
 5 files changed, 49 insertions(+), 23 deletions(-)

diff --git a/thorn/include/kernel/arm/sysregs.h b/thorn/include/kernel/arm/sysregs.h
index 98acd8b..ccdda11 100644
--- a/thorn/include/kernel/arm/sysregs.h
+++ b/thorn/include/kernel/arm/sysregs.h
@@ -43,7 +43,9 @@
 // ESR_EL1, Exception Syndrome Register (EL1). Page 2431 of AArch64-Reference-Manual.
 // ***************************************
 
-#define ESR_ELx_EC_SHIFT 26
-#define ESR_ELx_EC_SVC64 0x15
+#define ESR_ELx_EC_SHIFT     26
+#define ESR_ELx_EC_SVC64     0x15
+#define ESR_ELx_EC_DABT_LOW  0b100100
+#define ESR_ELx_EC_DABT_SAME 0b100101
 
 #endif /*_ROSE_K_A_SYSREGS_H*/
diff --git a/thorn/include/kernel/mmu.h b/thorn/include/kernel/mmu.h
index b9537a6..169ac60 100644
--- a/thorn/include/kernel/mmu.h
+++ b/thorn/include/kernel/mmu.h
@@ -45,7 +45,7 @@ static volatile unsigned int __attribute__ ((aligned (16))) buffer[32];
 void init_pages ();
 void init_mmu (void);
 
-void data_abort_el1 (ptr_t far, ptr_t esr);
+void data_abort_el0 (ptr_t far, ptr_t esr);
 
 #endif
 #endif//_ROSE_MMU_H
\ No newline at end of file
diff --git a/thorn/src/common/printf.c b/thorn/src/common/printf.c
index 059ee24..80549a9 100644
--- a/thorn/src/common/printf.c
+++ b/thorn/src/common/printf.c
@@ -206,6 +206,19 @@ void tfp_format (void * putp, putcf putf, char * fmt, va_list va) {
                                   unsigned int), 16, (ch == 'P'), bf);
                     putchw (putp, putf, w, lz, bf);
                     break;
+                case 'b':
+                case 'B':
+                    putf (putp, '0');
+                    putf (putp, 'b');
+#ifdef PRINTF_LONG_SUPPORT
+                    if (lng)
+                        uli2a (va_arg (va, unsigned long int), 2, (ch == 'B'), bf);
+                    else
+#endif
+                    ui2a (va_arg (va,
+                                  unsigned int), 2, (ch == 'B'), bf);
+                    putchw (putp, putf, w, lz, bf);
+                    break;
                 case '%':
                     putf (putp, ch);
                 default:
diff --git a/thorn/src/kernel/entry.S b/thorn/src/kernel/entry.S
index 4f44a25..950d6ea 100644
--- a/thorn/src/kernel/entry.S
+++ b/thorn/src/kernel/entry.S
@@ -1,6 +1,7 @@
 #include "kernel/arm/sysregs.h"
 #include "kernel/entry.h"
 #include "kernel/sys.h"
+#include "kernel/mmu.h"
 
 	.macro handle_invalid_entry el, type
 	kernel_entry \el
@@ -8,7 +9,7 @@
 	mrs	x1, esr_el1
 	mrs	x2, elr_el1
 	bl	show_invalid_entry_message
-	b	err_hang
+	b 	exit_process
 	.endm
 
 	.macro	ventry	label
@@ -156,38 +157,48 @@ el0_irq:
 
 el0_sync:
 	kernel_entry 0
-	mrs	x25, esr_el1				// read the syndrome register
-	lsr	x24, x25, #ESR_ELx_EC_SHIFT		// exception class
-	cmp	x24, #ESR_ELx_EC_SVC64			// SVC in 64-bit state
+	mrs	x25, esr_el1													// read the syndrome register
+	lsr	x24, x25, #ESR_ELx_EC_SHIFT						// exception class
+	cmp	x24, #ESR_ELx_EC_SVC64								// SVC in 64-bit state
 	b.eq	el0_svc
+	cmp x24, #ESR_ELx_EC_DABT_LOW
+	b.eq 	el0_da
 	handle_invalid_entry 0, SYNC_ERROR
 
-sc_nr	.req	x25					// number of system calls
-scno	.req	x26					// syscall number
-stbl	.req	x27					// syscall table pointer
+sc_nr	.req	x25															// number of system calls
+scno	.req	x26															// syscall number
+stbl	.req	x27															// syscall table pointer
 
 el0_svc:
-	adr	stbl, sys_call_table			// load syscall table pointer
-	uxtw	scno, w8				// syscall number in w8
+	adr	stbl, sys_call_table									// load syscall table pointer
+	uxtw	scno, w8														// syscall number in w8
 	mov	sc_nr, #__NR_syscalls
 	bl	enable_irq
 	cmp     scno, sc_nr                     	// check upper syscall limit
 	b.hs	ni_sys
 
-	ldr	x16, [stbl, scno, lsl #3]		// address in the syscall table
-	blr	x16					// call sys_* routine
+	ldr	x16, [stbl, scno, lsl #3]							// address in the syscall table
+	blr	x16																		// call sys_* routine
 	b	ret_from_syscall
 ni_sys:
 	handle_invalid_entry 0, SYSCALL_ERROR
 ret_from_syscall:
 	bl	disable_irq
-	str	x0, [sp, #S_X0]				// returned x0
+	str	x0, [sp, #S_X0]												// returned x0
 	kernel_exit 0
 
+el0_da:
+	bl enable_irq
+	mrs x0, far_el1
+	mrs x1, esr_el1
+	bl data_abort_el0
+    bl disable_irq
+    eret
+
 .globl ret_from_fork
 ret_from_fork:
 	bl	schedule_tail
-	cbz	x19, ret_to_user			// not a kernel thread
+	cbz	x19, ret_to_user											// not a kernel thread
 	mov	x0, x20
 	blr	x19
 ret_to_user:
@@ -195,4 +206,4 @@ ret_to_user:
 	kernel_exit 0
 
 .globl err_hang
-err_hang: b err_hang
+err_hang: b err_hang
\ No newline at end of file
diff --git a/thorn/src/kernel/mmu.c b/thorn/src/kernel/mmu.c
index d500828..49ab379 100644
--- a/thorn/src/kernel/mmu.c
+++ b/thorn/src/kernel/mmu.c
@@ -129,29 +129,29 @@ void init_mmu () {
     LOG ("Set SCTLR flags and enable MMU");
 }
 
-void data_abort_el1 (ptr_t far, ptr_t esr) {
+void data_abort_el0 (ptr_t far, ptr_t esr) {
     byte_t type  = (esr >> 2) & 0b11;
     byte_t level = esr & 0b11;
     esr &= 0b111111;
 
-    printf ("EL 1 - ");
+    printf ("EL 0 - ");
     printf ("FAR_EL1: %p - ", far);
     printf ("ESR_EL1: %b\n\r", esr);
 
     switch (type) {
         case 0b00:// Address size fault
-            printf ("Address size fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            printf ("Address size fault during level %u of table walk on lookup of address %p.\r\n", level, far);
             //            exit_process ();
             break;
         case 0b01:// Translation fault
-            printf ("Translation fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            printf ("Translation fault during level %u of table walk on lookup of address %p.\r\n", level, far);
             break;
         case 0b10:// Access flag fault
-            printf ("Access flag fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            printf ("Access flag fault during level %u of table walk on lookup of address %p.\r\n", level, far);
             //            exit_process ();
             break;
         case 0b11:// Permission fault
-            printf ("Segmentation fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
+            printf ("Permission fault during level %u of table walk on lookup of address %p.\r\n", level, far);
             //            exit_process ();
             break;
     }

From d074e77f71bdf81125b76646f724ad99273cf6eb Mon Sep 17 00:00:00 2001
From: Max Streitberger <max.streitberger@gmail.com>
Date: Thu, 4 Nov 2021 13:55:00 +0100
Subject: [PATCH 12/21] feat(mmu): WIP

---
 bulb/Makefile                               | 124 ----------
 bulb/include/common/debug.h                 |  16 --
 bulb/include/common/font.h                  |  42 ----
 bulb/include/common/gpu.h                   |  57 -----
 bulb/include/common/logging.h               |  27 ---
 bulb/include/common/printf.h                | 107 ---------
 bulb/include/common/screen.h                |  20 --
 bulb/include/common/status_led.h            |  24 --
 bulb/include/common/stdbool.h               |  10 -
 bulb/include/common/stddef.h                |  10 -
 bulb/include/common/utils.h                 |  12 -
 bulb/include/kernel/arm/sysregs.h           |  51 ----
 bulb/include/kernel/entry.h                 |  35 ---
 bulb/include/kernel/irq.h                   |  23 --
 bulb/include/kernel/mailbox.h               |  40 ----
 bulb/include/kernel/mini_uart.h             |  33 ---
 bulb/include/kernel/mm.h                    |  33 ---
 bulb/include/kernel/mmu.h                   |  51 ----
 bulb/include/kernel/peripherals/base.h      |   6 -
 bulb/include/kernel/peripherals/gpio.h      |  12 -
 bulb/include/kernel/peripherals/gpu.h       |  10 -
 bulb/include/kernel/peripherals/irq.h       |  37 ---
 bulb/include/kernel/peripherals/mailbox.h   |  19 --
 bulb/include/kernel/peripherals/mini_uart.h |  25 --
 bulb/include/kernel/peripherals/power.h     |  21 --
 bulb/include/kernel/peripherals/timer.h     |  19 --
 bulb/include/kernel/power.h                 |  14 --
 bulb/include/kernel/timer.h                 |   8 -
 bulb/src/common/debug.c                     |  29 ---
 bulb/src/common/font.c                      | 203 ----------------
 bulb/src/common/gpu.c                       | 137 -----------
 bulb/src/common/printf.c                    | 243 --------------------
 bulb/src/common/screen.c                    |  14 --
 bulb/src/common/status_led.c                |  55 -----
 bulb/src/common/utils.S                     |  21 --
 bulb/src/config.txt                         |   2 -
 bulb/src/kernel/boot.S                      |  52 -----
 bulb/src/kernel/entry.S                     | 181 ---------------
 bulb/src/kernel/irq.S                       |  15 --
 bulb/src/kernel/irq.c                       |  51 ----
 bulb/src/kernel/kernel.c                    |  64 ------
 bulb/src/kernel/mailbox.c                   |  52 -----
 bulb/src/kernel/mini_uart.c                 |  87 -------
 bulb/src/kernel/mm.S                        |  14 --
 bulb/src/kernel/mm.c                        |  19 --
 bulb/src/kernel/mmu.c                       | 175 --------------
 bulb/src/kernel/power.c                     |  19 --
 bulb/src/kernel/timer.c                     |  23 --
 bulb/src/linker.ld                          |  19 --
 thorn/include/common/utils.h                |   4 +
 thorn/include/kernel/sched.h                |  21 +-
 thorn/src/common/utils.S                    |  17 ++
 thorn/src/kernel/entry.S                    |   7 +-
 thorn/src/kernel/fork.c                     |  12 +-
 thorn/src/kernel/irq.c                      |   2 +-
 thorn/src/kernel/kernel.c                   |   2 +-
 thorn/src/kernel/sched.c                    |  14 +-
 57 files changed, 61 insertions(+), 2379 deletions(-)
 delete mode 100644 bulb/Makefile
 delete mode 100644 bulb/include/common/debug.h
 delete mode 100644 bulb/include/common/font.h
 delete mode 100644 bulb/include/common/gpu.h
 delete mode 100644 bulb/include/common/logging.h
 delete mode 100644 bulb/include/common/printf.h
 delete mode 100644 bulb/include/common/screen.h
 delete mode 100644 bulb/include/common/status_led.h
 delete mode 100644 bulb/include/common/stdbool.h
 delete mode 100644 bulb/include/common/stddef.h
 delete mode 100644 bulb/include/common/utils.h
 delete mode 100644 bulb/include/kernel/arm/sysregs.h
 delete mode 100644 bulb/include/kernel/entry.h
 delete mode 100644 bulb/include/kernel/irq.h
 delete mode 100644 bulb/include/kernel/mailbox.h
 delete mode 100644 bulb/include/kernel/mini_uart.h
 delete mode 100644 bulb/include/kernel/mm.h
 delete mode 100644 bulb/include/kernel/mmu.h
 delete mode 100644 bulb/include/kernel/peripherals/base.h
 delete mode 100644 bulb/include/kernel/peripherals/gpio.h
 delete mode 100644 bulb/include/kernel/peripherals/gpu.h
 delete mode 100644 bulb/include/kernel/peripherals/irq.h
 delete mode 100644 bulb/include/kernel/peripherals/mailbox.h
 delete mode 100644 bulb/include/kernel/peripherals/mini_uart.h
 delete mode 100644 bulb/include/kernel/peripherals/power.h
 delete mode 100644 bulb/include/kernel/peripherals/timer.h
 delete mode 100644 bulb/include/kernel/power.h
 delete mode 100644 bulb/include/kernel/timer.h
 delete mode 100644 bulb/src/common/debug.c
 delete mode 100644 bulb/src/common/font.c
 delete mode 100644 bulb/src/common/gpu.c
 delete mode 100644 bulb/src/common/printf.c
 delete mode 100644 bulb/src/common/screen.c
 delete mode 100644 bulb/src/common/status_led.c
 delete mode 100644 bulb/src/common/utils.S
 delete mode 100644 bulb/src/config.txt
 delete mode 100644 bulb/src/kernel/boot.S
 delete mode 100644 bulb/src/kernel/entry.S
 delete mode 100644 bulb/src/kernel/irq.S
 delete mode 100644 bulb/src/kernel/irq.c
 delete mode 100644 bulb/src/kernel/kernel.c
 delete mode 100644 bulb/src/kernel/mailbox.c
 delete mode 100644 bulb/src/kernel/mini_uart.c
 delete mode 100644 bulb/src/kernel/mm.S
 delete mode 100644 bulb/src/kernel/mm.c
 delete mode 100644 bulb/src/kernel/mmu.c
 delete mode 100644 bulb/src/kernel/power.c
 delete mode 100644 bulb/src/kernel/timer.c
 delete mode 100644 bulb/src/linker.ld

diff --git a/bulb/Makefile b/bulb/Makefile
deleted file mode 100644
index e510523..0000000
--- a/bulb/Makefile
+++ /dev/null
@@ -1,124 +0,0 @@
-# | Makefile for the Rose project (github.com/anarchuser/rose)
-# | Merged from https://jsandler18.github.io/ and https://github.com/s-matyukevich/raspberry-pi-os
-
-# Cross-compiler
-ARMGNU ?= aarch64-none-elf
-
-# Resolve Mac / linux issues
-HOST_OS = $(shell uname -s)
-
-# Build target
-IMAGE_NAME = $(shell basename `pwd`)
-
-# Options for C, Asembly, and the linker, respectively
-COPS   = -Wall -nostdlib -nostartfiles -ffreestanding -Iinclude -mgeneral-regs-only
-ASMOPS = -Iinclude
-LOPS   = -ffreestanding -nostdlib
-
-# Mount point and boot partition
-MNT = $(MNT_$(HOST_OS))
-MNT_Linux  = ../mnt
-MNT_Darwin = /Volumes/boot
-
-# Serial connection config
-BAUD_RATE = 115200
-SERIAL_PORT = $(SERIAL_PORT_$(HOST_OS))
-SERIAL_PORT_Linux      = /dev/$(shell ls /dev | grep ttyUSB    | head -n 2 | tail -n 1)
-SERIAL_PORT_Darwin     = /dev/$(shell ls /dev | grep usbserial | head -n 2 | tail -n 1)
-
-# Directories for built files, source files (kernel and common) and header files (include)
-BUILD   = build
-SRC     = src
-KERNEL  = kernel
-COMMON  = common
-INCLUDE = include
-
-# Assemble lists of corresponding source files for assembly, kernel and common
-SRC_KERNEL = $(wildcard $(SRC)/$(KERNEL)/*.c)
-ASM_KERNEL = $(wildcard $(SRC)/$(KERNEL)/*.S)
-SRC_COMMON = $(wildcard $(SRC)/$(COMMON)/*.c)
-ASM_COMMON = $(wildcard $(SRC)/$(COMMON)/*.S)
-
-# Assemble list of compiled objects, correspondingly
-OBJECTS  = $(patsubst $(SRC)/$(KERNEL)/%.c, $(BUILD)/$(SRC)/$(KERNEL)/%_c.o, $(SRC_KERNEL))
-OBJECTS += $(patsubst $(SRC)/$(KERNEL)/%.S, $(BUILD)/$(SRC)/$(KERNEL)/%_S.o, $(ASM_KERNEL))
-OBJECTS += $(patsubst $(SRC)/$(COMMON)/%.c, $(BUILD)/$(SRC)/$(COMMON)/%_c.o, $(SRC_COMMON))
-OBJECTS += $(patsubst $(SRC)/$(COMMON)/%.S, $(BUILD)/$(SRC)/$(COMMON)/%_S.o, $(ASM_COMMON))
-
-# Ensure make still works if someone creates a file named like follows:
-.PHONY: build clean flash flash-Linux flash-Darwin emulate reboot poweroff send resend
-
-# Default target (invoked by `make` or `make build`).
-build: $(IMAGE_NAME).img
-
-# Build kernel executable and linkable file where we can extract the kernel from
-$(IMAGE_NAME).elf: $(OBJECTS) $(SRC)/linker.ld
-	$(ARMGNU)-ld -T $(SRC)/linker.ld -o $(BUILD)/$(IMAGE_NAME).elf $(OBJECTS)
-
-# Build actual kernel image
-$(IMAGE_NAME).img: $(SRC)/linker.ld $(OBJECTS) $(IMAGE_NAME).elf
-	$(ARMGNU)-objcopy $(BUILD)/$(IMAGE_NAME).elf -O binary $(IMAGE_NAME).img
-
-# All kernel source targets
-$(BUILD)/$(SRC)/$(KERNEL)/%_c.o: $(SRC)/$(KERNEL)/%.c
-	mkdir -p $(@D)
-	$(ARMGNU)-gcc $(COPS) -MMD -c $< -o $@
-
-# All assembly source targets
-$(BUILD)/$(SRC)/$(KERNEL)/%_S.o: $(SRC)/$(KERNEL)/%.S
-	mkdir -p $(@D)
-	$(ARMGNU)-gcc $(ASMOPS) -MMD -c $< -o $@
-
-# All common source targets
-$(BUILD)/$(SRC)/$(COMMON)/%_c.o: $(SRC)/$(COMMON)/%.c
-	mkdir -p $(@D)
-	$(ARMGNU)-gcc $(COPS) -MMD -c $< -o $@
-
-# All assembly source targets
-$(BUILD)/$(SRC)/$(COMMON)/%_S.o: $(SRC)/$(COMMON)/%.S
-	mkdir -p $(@D)
-	$(ARMGNU)-gcc $(ASMOPS) -MMD -c $< -o $@
-
-# Compile lists with the dependencies between objects
-DEP_FILES = $(OBJECTS:%.o=%.d)
-	-include $(DEP_FILES)
-
-# Remove kernel and build directory
-clean:
-	rm -rf $(BUILD) *.img
-
-# Mount boot partition of SD card onto set mount point to copy image onto it
-flash: flash-$(HOST_OS)
-
-flash-Linux: $(IMAGE_NAME).img
-	mkdir -p $(MNT)
-	mount $(MNT)
-	cp $(IMAGE_NAME).img $(MNT)/kernel8.img
-	cp $(SRC)/config.txt $(MNT)
-	sync
-	sleep 1
-	umount $(MNT)
-
-flash-Darwin: $(IMAGE_NAME).img
-	cp $(IMAGE_NAME).img $(MNT)/kernel8.img
-	cp $(SRC)/config.txt $(MNT)
-	sync
-	diskutil unmount $(MNT)
-
-resend: reboot send
-
-send: $(IMAGE_NAME).img
-	printf "0: %.8x" $(shell wc -c < $(IMAGE_NAME).img) | xxd -r -g0 > $(SERIAL_PORT)
-	cat $(IMAGE_NAME).img > $(SERIAL_PORT)
-
-# Run on qemu
-emulate: $(IMAGE_NAME).img
-	qemu-img resize $(IMAGE_NAME).img -f raw 4294967296
-	qemu-system-aarch64 -cpu cortex-a72 -machine type=raspi3 -m 1024 -kernel $(IMAGE_NAME).img -nographic -serial null -chardev stdio,id=uart1 -serial chardev:uart1 -monitor none
-
-poweroff:
-	$(MAKE) -C .. poweroff
-
-reboot:
-	$(MAKE) -C .. reboot
-
diff --git a/bulb/include/common/debug.h b/bulb/include/common/debug.h
deleted file mode 100644
index 99e2ec3..0000000
--- a/bulb/include/common/debug.h
+++ /dev/null
@@ -1,16 +0,0 @@
-#ifndef _ROSE_C_DEBUG_H
-#define _ROSE_DEBUG_H
-
-#include "common/logging.h"
-#include "common/printf.h"
-#include "common/stddef.h"
-
-#define CHECKPOINT LOG ("Checkpoint");
-
-void print_hex (unsigned char dec);
-
-void hex_dump (byte_t * array);
-
-void int_dump (unsigned int * array);
-
-#endif//_ROSE_C_DEBUG_H
\ No newline at end of file
diff --git a/bulb/include/common/font.h b/bulb/include/common/font.h
deleted file mode 100644
index 0791dde..0000000
--- a/bulb/include/common/font.h
+++ /dev/null
@@ -1,42 +0,0 @@
-#ifndef _ROSE_C_FONT_H
-#define _ROSE_C_FONT_H
-
-#define FONT_SIZE       8
-#define FONT_FACTOR     4
-#define FONT_REAL_WIDTH (FONT_SIZE * FONT_FACTOR)
-
-// Spacing between lines in pixels
-#define FONT_SPACING     4
-#define FONT_REAL_HEIGHT (FONT_REAL_WIDTH + FONT_SPACING)
-
-// Width of horizontal tabs in characters
-#define FONT_TAB_SIZE       4
-#define FONT_TAB_REAL_WIDTH (FONT_TAB_SIZE * FONT_REAL_WIDTH)
-
-// If this is defined, scrollback is used
-#define FONT_SCROLLBACK
-// Scroll by this amount at the same time. High = fast, low = fancy
-#define FONT_SB_LINES 1
-
-#include "common/gpu.h"
-#include "common/screen.h"
-#include "kernel/mm.h"
-
-static point_t cursor = {0, 0};
-
-static volatile color_t font_bg        = {0x00, 0x00, 0x00, 0x00};
-static volatile color_t font_normal_fg = {0xC0, 0xC0, 0xC0, 0x00};
-static volatile color_t font_error_fg  = {0x00, 0x00, 0xC0, 0x00};
-static volatile color_t font_fg;
-
-const unsigned long long int * font (int c);
-
-void printc (char c);
-void printc_location (point_t point, char c);
-
-void putc_screen (void * p, char c);
-
-void font_set_normal (void);
-void font_set_error (void);
-
-#endif
diff --git a/bulb/include/common/gpu.h b/bulb/include/common/gpu.h
deleted file mode 100644
index 1237103..0000000
--- a/bulb/include/common/gpu.h
+++ /dev/null
@@ -1,57 +0,0 @@
-#ifndef _ROSE_C_GPU_H
-#define _ROSE_C_GPU_H
-
-#include "common/printf.h"
-
-#include "common/stdbool.h"
-#include "common/stddef.h"
-#include "kernel/mailbox.h"
-#include "kernel/mm.h"
-#include "kernel/peripherals/gpu.h"
-
-// Reference:
-// https://jsandler18.github.io/extra/prop-channel.html
-
-// Uncomment to override physical / virtual screen size with the values defined below
-#define GPU_OVERRIDE_PHYSICAL_SCREEN
-
-#define GPU_SCREEN_WIDTH  1920// Width used if Override is enabled
-#define GPU_SCREEN_HEIGHT 1080// Height used if Override is enabled
-
-#define GPU_VIRTUAL_WIDTH  GPU_SCREEN_WIDTH
-#define GPU_VIRTUAL_HEIGHT GPU_SCREEN_HEIGHT
-
-#define GPU_COLOUR_DEPTH 32
-
-#define VC_SDRAM_OFFSET 0x3FFFFFFF
-
-typedef struct {
-    byte_t blue;
-    byte_t green;
-    byte_t red;
-    byte_t alpha;
-} color_t;
-
-typedef struct {
-    color_t *    fb;
-    unsigned int fb_size;
-    short        virtual_width;
-    short        virtual_height;
-    short        pitch;
-    short        colour_depth;
-} fb_info_t;
-
-static volatile unsigned int __attribute__ ((aligned (16))) gpu_msg_buffer[128];
-
-static fb_info_t fb_info;
-
-bool init_gpu (void);
-
-color_t * get_fb (void);
-
-fb_info_t const * get_fb_info (void);
-
-bool blank_screen (bool blank);
-bool toggle_blank_screen (void);
-
-#endif//_ROSE_C_GPU_H
\ No newline at end of file
diff --git a/bulb/include/common/logging.h b/bulb/include/common/logging.h
deleted file mode 100644
index 6203d6b..0000000
--- a/bulb/include/common/logging.h
+++ /dev/null
@@ -1,27 +0,0 @@
-#ifndef _ROSE_C_LOGGING_H
-#define _ROSE_C_LOGGING_H
-
-#include "common/printf.h"
-
-#define LOG(msg)                                                           \
-    do {                                                                   \
-        static int __counter__ = 0;                                        \
-        printf (__FILE__ ":%d:[%d] %s\r\n", __LINE__, __counter__++, msg); \
-    } while (0)
-
-#define ERROR(msg)                                                         \
-    do {                                                                   \
-        static int __counter__ = 0;                                        \
-        font_set_error ();                                                 \
-        printf (__FILE__ ":%d:[%d] %s\r\n", __LINE__, __counter__++, msg); \
-        font_set_normal ();                                                \
-    } while (0)
-
-#define ASSERT(expr)                  \
-    do {                              \
-        if (! (expr))                 \
-            LOG ("Assertion failed"); \
-    } while (0)
-
-
-#endif /*_ROSE_C_LOGGING_H*/
diff --git a/bulb/include/common/printf.h b/bulb/include/common/printf.h
deleted file mode 100644
index 382087b..0000000
--- a/bulb/include/common/printf.h
+++ /dev/null
@@ -1,107 +0,0 @@
-/*
-File: printf.h
-
-Copyright (C) 2004  Kustaa Nyholm
-
-This library is free software; you can redistribute it and/or
-modify it under the terms of the GNU Lesser General Public
-License as published by the Free Software Foundation; either
-version 2.1 of the License, or (at your option) any later version.
-
-This library is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
-See the GNU Lesser General Public License for more details.
-
-You should have received a copy of the GNU Lesser General Public
-License along with this library; if not, write to the Free Software
-Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-This library is really just two files: 'printf.h' and 'printf.c'.
-
-They provide a simple and small (+200 loc) printf functionality to
-be used in embedded systems.
-
-I've found them so usefull in debugging that I do not bother with a
-debugger at all.
-
-They are distributed in source form, so to use them, just compile them
-into your project.
-
-Two printf variants are provided: printf and sprintf.
-
-The formats supported by this implementation are: 'd' 'u' 'c' 's' 'x' 'X'.
-
-Zero padding and field width are also supported.
-
-If the library is compiled with 'PRINTF_SUPPORT_LONG' defined then the
-long specifier is also
-supported. Note that this will pull in some long math routines (pun intended!)
-and thus make your executable noticably longer.
-
-The memory foot print of course depends on the target cpu, compiler and
-compiler options, but a rough guestimate (based on a H8S target) is about
-1.4 kB for code and some twenty 'int's and 'char's, say 60 bytes of stack space.
-Not too bad. Your milage may vary. By hacking the source code you can
-get rid of some hunred bytes, I'm sure, but personally I feel the balance of
-functionality and flexibility versus  code size is close to optimal for
-many embedded systems.
-
-To use the printf you need to supply your own character output function,
-something like :
-
-	void putc ( void* p, char c)
-		{
-		while (!SERIAL_PORT_EMPTY) ;
-		SERIAL_PORT_TX_REGISTER = c;
-		}
-
-Before you can call printf you need to initialize it to use your
-character output function with something like:
-
-	init_printf(NULL,putc);
-
-Notice the 'NULL' in 'init_printf' and the parameter 'void* p' in 'putc',
-the NULL (or any pointer) you pass into the 'init_printf' will eventually be
-passed to your 'putc' routine. This allows you to pass some storage space (or
-anything really) to the character output function, if necessary.
-This is not often needed but it was implemented like that because it made
-implementing the sprintf function so neat (look at the source code).
-
-The code is re-entrant, except for the 'init_printf' function, so it
-is safe to call it from interupts too, although this may result in mixed output.
-If you rely on re-entrancy, take care that your 'putc' function is re-entrant!
-
-The printf and sprintf functions are actually macros that translate to
-'tfp_printf' and 'tfp_sprintf'. This makes it possible
-to use them along with 'stdio.h' printf's in a single source file.
-You just need to undef the names before you include the 'stdio.h'.
-Note that these are not function like macros, so if you have variables
-or struct members with these names, things will explode in your face.
-Without variadic macros this is the best we can do to wrap these
-fucnction. If it is a problem just give up the macros and use the
-functions directly or rename them.
-
-For further details see source code.
-
-regs Kusti, 23.10.2004
-*/
-
-
-#ifndef __TFP_PRINTF__
-#define __TFP_PRINTF__
-
-#include <stdarg.h>
-
-void init_printf (void * putp, void (*putf) (void *, char));
-
-void tfp_printf (char * fmt, ...);
-
-void tfp_sprintf (char * s, char * fmt, ...);
-
-void tfp_format (void * putp, void (*putf) (void *, char), char * fmt, va_list va);
-
-#define printf  tfp_printf
-#define sprintf tfp_sprintf
-
-#endif
diff --git a/bulb/include/common/screen.h b/bulb/include/common/screen.h
deleted file mode 100644
index 3e969d7..0000000
--- a/bulb/include/common/screen.h
+++ /dev/null
@@ -1,20 +0,0 @@
-#ifndef _ROSE_C_SCREEN_H
-#define _ROSE_C_SCREEN_H
-#include "common/gpu.h"
-
-typedef struct {
-    unsigned int x, y;
-} point_t;
-
-// point_t point (unsigned int x, unsigned int y);
-#define POINT(x, y) \
-    (point_t) {     \
-        x, y        \
-    }
-
-void drawpx (point_t p, color_t color);
-
-short get_max_width ();
-short get_max_height ();
-
-#endif//_ROSE_C_SCREEN_H
diff --git a/bulb/include/common/status_led.h b/bulb/include/common/status_led.h
deleted file mode 100644
index 0a7096e..0000000
--- a/bulb/include/common/status_led.h
+++ /dev/null
@@ -1,24 +0,0 @@
-#ifndef _ROSE_C_STATUS_LED_H
-#define _ROSE_C_STATUS_LED_H
-
-#include "common/stdbool.h"
-#include "kernel/mailbox.h"
-
-// Following https://github.com/mathlizee/Rasperry-Pi-3
-
-enum {
-    STATUS_LED = 42,
-    POWER_LED  = 130
-};
-
-static volatile unsigned int __attribute__ ((aligned (16))) led_msg_buffer[32];
-
-
-bool get_led (int pin);
-
-void set_led (bool status, int pin);
-
-bool toggle_led (int pin);
-
-
-#endif//_ROSE_C_STATUS_LED_H
diff --git a/bulb/include/common/stdbool.h b/bulb/include/common/stdbool.h
deleted file mode 100644
index 2c03282..0000000
--- a/bulb/include/common/stdbool.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#ifndef _ROSE_C_BOOL_H
-#define _ROSE_C_BOOL_H
-
-#define true 1
-#define false 0
-#define __bool_true_false_are_defined
-
-typedef char bool;
-
-#endif /*_ROSE_C_BOOL_H*/
diff --git a/bulb/include/common/stddef.h b/bulb/include/common/stddef.h
deleted file mode 100644
index 8d9feaa..0000000
--- a/bulb/include/common/stddef.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#ifndef _ROSE_C_STDDEF_H
-#define _ROSE_C_STDDEF_H
-
-#define NULL 0
-
-#define ptr_t unsigned long
-
-#define byte_t unsigned char
-
-#endif//_ROSE_C_STDDEF_H
\ No newline at end of file
diff --git a/bulb/include/common/utils.h b/bulb/include/common/utils.h
deleted file mode 100644
index 29b53a1..0000000
--- a/bulb/include/common/utils.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _ROSE_C_BOOT_H
-#define _ROSE_C_BOOT_H
-
-extern void delay (unsigned long);
-
-extern void put32 (unsigned long, unsigned int);
-
-extern unsigned int get32 (unsigned long);
-
-extern int get_el (void);
-
-#endif /*_ROSE_C_BOOT_H */
diff --git a/bulb/include/kernel/arm/sysregs.h b/bulb/include/kernel/arm/sysregs.h
deleted file mode 100644
index ccdda11..0000000
--- a/bulb/include/kernel/arm/sysregs.h
+++ /dev/null
@@ -1,51 +0,0 @@
-#ifndef _ROSE_K_A_SYSREGS_H
-#define _ROSE_K_A_SYSREGS_H
-
-// ***************************************
-// SCTLR_EL1, System Control Register (EL1), Page 2654 of AArch64-Reference-Manual.
-// ***************************************
-
-#define SCTLR_RESERVED          (3 << 28) | (3 << 22) | (1 << 20) | (1 << 11)
-#define SCTLR_EE_LITTLE_ENDIAN  (0 << 25)
-#define SCTLR_EOE_LITTLE_ENDIAN (0 << 24)
-#define SCTLR_I_CACHE_DISABLED  (0 << 12)
-#define SCTLR_D_CACHE_DISABLED  (0 << 2)
-#define SCTLR_MMU_DISABLED      (0 << 0)
-#define SCTLR_MMU_ENABLED       (1 << 0)
-
-#define SCTLR_VALUE_MMU_DISABLED (SCTLR_RESERVED | SCTLR_EE_LITTLE_ENDIAN | SCTLR_I_CACHE_DISABLED | SCTLR_D_CACHE_DISABLED | SCTLR_MMU_DISABLED)
-
-// ***************************************
-// HCR_EL2, Hypervisor Configuration Register (EL2), Page 2487 of AArch64-Reference-Manual.
-// ***************************************
-
-#define HCR_RW    (1 << 31)
-#define HCR_VALUE HCR_RW
-
-// ***************************************
-// SCR_EL3, Secure Configuration Register (EL3), Page 2648 of AArch64-Reference-Manual.
-// ***************************************
-
-#define SCR_RESERVED (3 << 4)
-#define SCR_RW       (1 << 10)
-#define SCR_NS       (1 << 0)
-#define SCR_VALUE    (SCR_RESERVED | SCR_RW | SCR_NS)
-
-// ***************************************
-// SPSR_EL3, Saved Program Status Register (EL3) Page 389 of AArch64-Reference-Manual.
-// ***************************************
-
-#define SPSR_MASK_ALL (7 << 6)
-#define SPSR_EL1h     (5 << 0)
-#define SPSR_VALUE    (SPSR_MASK_ALL | SPSR_EL1h)
-
-// ***************************************
-// ESR_EL1, Exception Syndrome Register (EL1). Page 2431 of AArch64-Reference-Manual.
-// ***************************************
-
-#define ESR_ELx_EC_SHIFT     26
-#define ESR_ELx_EC_SVC64     0x15
-#define ESR_ELx_EC_DABT_LOW  0b100100
-#define ESR_ELx_EC_DABT_SAME 0b100101
-
-#endif /*_ROSE_K_A_SYSREGS_H*/
diff --git a/bulb/include/kernel/entry.h b/bulb/include/kernel/entry.h
deleted file mode 100644
index 0152f82..0000000
--- a/bulb/include/kernel/entry.h
+++ /dev/null
@@ -1,35 +0,0 @@
-#ifndef _ROSE_K_ENTRY_H
-#define _ROSE_K_ENTRY_H
-
-#define S_FRAME_SIZE 272// size of all saved registers
-#define S_X0         0  // offset of x0 register in saved stack frame
-
-#define SYNC_INVALID_EL1t  0
-#define IRQ_INVALID_EL1t   1
-#define FIQ_INVALID_EL1t   2
-#define ERROR_INVALID_EL1t 3
-
-#define SYNC_INVALID_EL1h  4
-#define IRQ_INVALID_EL1h   5
-#define FIQ_INVALID_EL1h   6
-#define ERROR_INVALID_EL1h 7
-
-#define SYNC_INVALID_EL0_64  8
-#define IRQ_INVALID_EL0_64   9
-#define FIQ_INVALID_EL0_64   10
-#define ERROR_INVALID_EL0_64 11
-
-#define SYNC_INVALID_EL0_32  12
-#define IRQ_INVALID_EL0_32   13
-#define FIQ_INVALID_EL0_32   14
-#define ERROR_INVALID_EL0_32 15
-
-#define SYNC_ERROR    16
-#define SYSCALL_ERROR 17
-
-#ifndef __ASSEMBLER__
-
-void ret_from_fork (void);
-
-#endif
-#endif
diff --git a/bulb/include/kernel/irq.h b/bulb/include/kernel/irq.h
deleted file mode 100644
index 9221696..0000000
--- a/bulb/include/kernel/irq.h
+++ /dev/null
@@ -1,23 +0,0 @@
-#ifndef _ROSE_K_IRQ_H
-#define _ROSE_K_IRQ_H
-
-#include "common/printf.h"
-#include "common/stddef.h"
-#include "common/utils.h"
-#include "kernel/arm/sysregs.h"
-#include "kernel/entry.h"
-#include "kernel/peripherals/irq.h"
-
-#include "kernel/mini_uart.h"
-
-void enable_interrupt_controller (void);
-
-void show_invalid_entry_message (int type, ptr_t esr, ptr_t address);
-
-void irq_vector_init (void);
-
-void enable_irq (void);
-
-void disable_irq (void);
-
-#endif /*_ROSE_K_IRQ_H */
diff --git a/bulb/include/kernel/mailbox.h b/bulb/include/kernel/mailbox.h
deleted file mode 100644
index b4f6dd8..0000000
--- a/bulb/include/kernel/mailbox.h
+++ /dev/null
@@ -1,40 +0,0 @@
-#ifndef _ROSE_K_MAILBOX_H
-#define _ROSE_K_MAILBOX_H
-
-#include "common/stdbool.h"
-#include "common/stddef.h"
-#include "common/utils.h"
-#include "kernel/mm.h"
-#include "kernel/peripherals/mailbox.h"
-
-#include "common/debug.h"
-#include "common/logging.h"
-
-#define DUMP_BUFFER false
-
-// Documentation:
-// https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
-
-typedef enum {
-    POWER = 0,
-    FRAMEBUFFER,
-    VIRTUAL_UART,
-    VCHIQ,
-    LEDS,
-    BUTTONS,
-    TOUCH_SCREEN,
-    RESERVED,
-    PROPERTY_ARM_VC,// Request from ARM for response by VC
-    PROPERTY_VC_ARM // Request from VC for response by ARM (Currently not in use)
-} channel_t;
-
-
-typedef struct {
-    unsigned int data    : 28;// most significant bits contain shared memory address
-    channel_t    channel : 4; // least four significant bits contain channel
-} mbox_message_t;
-
-// Send message and check responses
-bool mailbox_request (volatile unsigned int * data_ptr, channel_t channel);
-
-#endif//_ROSE_K_MAILBOX_H
diff --git a/bulb/include/kernel/mini_uart.h b/bulb/include/kernel/mini_uart.h
deleted file mode 100644
index 46499cf..0000000
--- a/bulb/include/kernel/mini_uart.h
+++ /dev/null
@@ -1,33 +0,0 @@
-#ifndef _ROSE_K_UART_H
-#ifndef _ROSE_K_MINI_UART_H
-#define _ROSE_K_MINI_UART_H
-
-#include "common/gpu.h"
-#include "common/stdbool.h"
-#include "common/utils.h"
-#include "kernel/peripherals/gpio.h"
-#include "kernel/peripherals/mini_uart.h"
-//#include "kernel/power.h"
-
-void mini_uart_init (void);
-
-char mini_uart_recv (void);
-
-void mini_uart_send (char c);
-
-void mini_uart_send_string (char * str);
-
-void handle_mini_uart_irq (void);
-
-// This function is required by printf function
-void mini_putc (void * p, char c);
-
-#define uart_init        mini_uart_init
-#define uart_recv        mini_uart_recv
-#define uart_send        mini_uart_send
-#define uart_send_string mini_uart_send_string
-
-#define putc mini_putc
-
-#endif /*_ROSE_K_MINI_UART_H */
-#endif /*_ROSE_K_UART_H */
diff --git a/bulb/include/kernel/mm.h b/bulb/include/kernel/mm.h
deleted file mode 100644
index 7acc222..0000000
--- a/bulb/include/kernel/mm.h
+++ /dev/null
@@ -1,33 +0,0 @@
-#ifndef _ROSE_K_MM_H
-#define _ROSE_K_MM_H
-
-#include "common/stddef.h"
-#include "peripherals/base.h"
-
-#define PAGE_SHIFT    12
-#define TABLE_SHIFT   9
-#define SECTION_SHIFT (PAGE_SHIFT + TABLE_SHIFT)
-
-#define PAGE_SIZE    (1 << PAGE_SHIFT)
-#define SECTION_SIZE (1 << SECTION_SHIFT)
-
-#define LOW_MEMORY  (2 * SECTION_SIZE)
-#define HIGH_MEMORY 0x70000000
-
-#define PAGING_MEMORY (HIGH_MEMORY - LOW_MEMORY)
-#define PAGING_PAGES  (PAGING_MEMORY / PAGE_SIZE)
-
-#ifndef __ASSEMBLER__
-
-extern char _start;
-#define KERNEL_START ((ptr_t) &_start)
-
-ptr_t get_free_page ();
-
-void free_page (ptr_t p);
-
-void memzero (ptr_t src, ptr_t n);
-
-#endif
-
-#endif /*_ROSE_K_MM_H */
diff --git a/bulb/include/kernel/mmu.h b/bulb/include/kernel/mmu.h
deleted file mode 100644
index b9537a6..0000000
--- a/bulb/include/kernel/mmu.h
+++ /dev/null
@@ -1,51 +0,0 @@
-#ifndef _ROSE_MMU_H
-#define _ROSE_MMU_H
-
-#ifndef __ASSEMBLER__
-
-// Implementation taken from
-// https://github.com/bztsrc/raspi3-tutorial/blob/master/10_virtualmemory/mmu.c
-
-#include "common/font.h"
-#include "common/logging.h"
-#include "common/status_led.h"
-#include "kernel/mini_uart.h"
-#include "kernel/peripherals/base.h"
-
-#define PAGESIZE 4096
-
-// granularity
-#define PT_PAGE   0b11// 4k granule
-#define PT_BLOCK  0b01// 2M granule
-// accessibility
-#define PT_KERNEL (0 << 6)   // privileged, supervisor EL1 access only
-#define PT_USER   (1 << 6)   // unprivileged, EL0 access allowed
-#define PT_RW     (0 << 7)   // read-write
-#define PT_RO     (1 << 7)   // read-only
-#define PT_AF     (1 << 10)  // accessed flag
-#define PT_NX     (1UL << 54)// no execute
-// shareability
-#define PT_OSH    (2 << 8)// outter shareable
-#define PT_ISH    (3 << 8)// inner shareable
-// defined in MAIR register
-#define PT_MEM    (0 << 2)// normal memory
-#define PT_DEV    (1 << 2)// device MMIO
-#define PT_NC     (2 << 2)// non-cachable
-
-#define TTBR_CNP 1
-
-#define RAM_IN_GB 8
-
-// get addresses from linker
-extern volatile unsigned char _data;
-extern volatile unsigned char _end;
-
-static volatile unsigned int __attribute__ ((aligned (16))) buffer[32];
-
-void init_pages ();
-void init_mmu (void);
-
-void data_abort_el1 (ptr_t far, ptr_t esr);
-
-#endif
-#endif//_ROSE_MMU_H
\ No newline at end of file
diff --git a/bulb/include/kernel/peripherals/base.h b/bulb/include/kernel/peripherals/base.h
deleted file mode 100644
index 12f55d7..0000000
--- a/bulb/include/kernel/peripherals/base.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef _ROSE_K_P_BASE_H
-#define _ROSE_K_P_BASE_H
-
-#define PBASE 0xFE000000
-
-#endif /*_ROSE_K_P_BASE_H */
diff --git a/bulb/include/kernel/peripherals/gpio.h b/bulb/include/kernel/peripherals/gpio.h
deleted file mode 100644
index 8354caf..0000000
--- a/bulb/include/kernel/peripherals/gpio.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _ROSE_K_P_GPIO_H
-#define _ROSE_K_P_GPIO_H
-
-#include "kernel/peripherals/base.h"
-
-#define GPFSEL1   (PBASE + 0x00200004)
-#define GPSET0    (PBASE + 0x0020001C)
-#define GPCLR0    (PBASE + 0x00200028)
-#define GPPUD     (PBASE + 0x00200094)
-#define GPPUDCLK0 (PBASE + 0x00200098)
-
-#endif /*_ROSE_K_P_GPIO_H */
diff --git a/bulb/include/kernel/peripherals/gpu.h b/bulb/include/kernel/peripherals/gpu.h
deleted file mode 100644
index 2408fba..0000000
--- a/bulb/include/kernel/peripherals/gpu.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#ifndef _ROSE_K_P_GPU_H
-#define _ROSE_K_P_GPU_H
-
-#define GPU_REQUEST_FRAMEBUFFER 0x40001
-#define GPU_BLANK_SCREEN        0x40002
-#define GPU_SET_SCREEN_SIZE     0x48003
-#define GPU_SET_VIRTUAL_SIZE    0x48004
-#define GPU_SET_COLOUR_DEPTH    0x48005
-
-#endif//_ROSE_K_P_GPU_H
\ No newline at end of file
diff --git a/bulb/include/kernel/peripherals/irq.h b/bulb/include/kernel/peripherals/irq.h
deleted file mode 100644
index 9900292..0000000
--- a/bulb/include/kernel/peripherals/irq.h
+++ /dev/null
@@ -1,37 +0,0 @@
-#ifndef _ROSE_K_P_IRQ_H
-#define _ROSE_K_P_IRQ_H
-
-#include "kernel/peripherals/base.h"
-
-#define GIC_BASE       0xFF840000
-#define GICD_DIST_BASE (GIC_BASE + 0x00001000)
-#define GICC_CPU_BASE  (GIC_BASE + 0x00002000)
-
-#define GICD_ENABLE_IRQ_BASE (GICD_DIST_BASE + 0x00000100)
-
-#define GICC_IAR  (GICC_CPU_BASE + 0x0000000C)
-#define GICC_EOIR (GICC_CPU_BASE + 0x00000010)
-
-#define GIC_IRQ_TARGET_BASE (GICD_DIST_BASE + 0x00000800)
-
-//VC (=VideoCore) starts at 96
-#define SYSTEM_TIMER_IRQ_0 (0x60)//96
-#define SYSTEM_TIMER_IRQ_1 (0x61)//97
-#define SYSTEM_TIMER_IRQ_2 (0x62)//98
-#define SYSTEM_TIMER_IRQ_3 (0x63)//99
-
-#define IRQ_BASIC_PENDING  (PBASE + 0x0000B200)
-#define IRQ_PENDING_1      (PBASE + 0x0000B204)
-#define IRQ_PENDING_2      (PBASE + 0x0000B208)
-#define FIQ_CONTROL        (PBASE + 0x0000B20C)
-#define ENABLE_IRQS_1      (PBASE + 0x0000B210)
-#define ENABLE_IRQS_2      (PBASE + 0x0000B214)
-#define ENABLE_BASIC_IRQS  (PBASE + 0x0000B218)
-#define DISABLE_IRQS_1     (PBASE + 0x0000B21C)
-#define DISABLE_IRQS_2     (PBASE + 0x0000B220)
-#define DISABLE_BASIC_IRQS (PBASE + 0x0000B224)
-
-#define MINI_UART_IRQ  (1 << 0)
-#define ENABLE_AUX_INT (1 << 29)
-
-#endif /*_ROSE_K_P_IRQ_H */
diff --git a/bulb/include/kernel/peripherals/mailbox.h b/bulb/include/kernel/peripherals/mailbox.h
deleted file mode 100644
index 37f664c..0000000
--- a/bulb/include/kernel/peripherals/mailbox.h
+++ /dev/null
@@ -1,19 +0,0 @@
-#ifndef _ROSE_K_P_MAILBOX_H
-#define _ROSE_K_P_MAILBOX_H
-
-#include "base.h"
-
-#define MBOX0 (PBASE + 0xB880)// Read from CPU
-#define MBOX1 (PBASE + 0xB840)// Write to CPU
-
-#define MBOX_READ   0x00
-#define MBOX_STATUS 0x18
-#define MBOX_IRQ    0x1C
-#define MBOX_WRITE  0x20
-
-#define MBOX_READ_EMPTY (1 << 30)
-#define MBOX_WRITE_FULL (1 << 31)
-
-#define MBOX_SUCCESS 0x80000000
-
-#endif//_ROSE_K_P_MAILBOX_H
\ No newline at end of file
diff --git a/bulb/include/kernel/peripherals/mini_uart.h b/bulb/include/kernel/peripherals/mini_uart.h
deleted file mode 100644
index b065deb..0000000
--- a/bulb/include/kernel/peripherals/mini_uart.h
+++ /dev/null
@@ -1,25 +0,0 @@
-#ifndef _ROSE_K_P_MINI_UART_H
-#define _ROSE_K_P_MINI_UART_H
-
-#include "base.h"
-
-#define SYSTEM_CLOCK_FREQ              500000000
-#define BAUD_RATE_REG(target_baudrate) ((SYSTEM_CLOCK_FREQ / target_baudrate / 8) - 1)
-
-#define AUX_IRQ_REG     (PBASE + 0x00215000)
-#define AUX_ENABLES     (PBASE + 0x00215004)
-#define AUX_MU_IO_REG   (PBASE + 0x00215040)
-#define AUX_MU_IER_REG  (PBASE + 0x00215044)
-#define AUX_MU_IIR_REG  (PBASE + 0x00215048)
-#define AUX_MU_LCR_REG  (PBASE + 0x0021504C)
-#define AUX_MU_MCR_REG  (PBASE + 0x00215050)
-#define AUX_MU_LSR_REG  (PBASE + 0x00215054)
-#define AUX_MU_MSR_REG  (PBASE + 0x00215058)
-#define AUX_MU_SCRATCH  (PBASE + 0x0021505C)
-#define AUX_MU_CNTL_REG (PBASE + 0x00215060)
-#define AUX_MU_STAT_REG (PBASE + 0x00215064)
-#define AUX_MU_BAUD_REG (PBASE + 0x00215068)
-
-#define ENABLE_MU_REC_INT (0xFD)
-
-#endif /*_ROSE_K_P_MINI_UART_H */
diff --git a/bulb/include/kernel/peripherals/power.h b/bulb/include/kernel/peripherals/power.h
deleted file mode 100644
index b02469f..0000000
--- a/bulb/include/kernel/peripherals/power.h
+++ /dev/null
@@ -1,21 +0,0 @@
-#ifndef _ROSE_K_P_POWER_H
-#define _ROSE_K_P_POWER_H
-
-#include "kernel/peripherals/base.h"
-
-#define PM_BASE PBASE + 0x100000
-
-#define PM_RSTC PM_BASE + 0x1c
-#define PM_WDOG PM_BASE + 0x24
-
-#define PM_WDOG_RESET            0000000000
-#define PM_PASSWORD              0x5a000000
-#define PM_WDOG_TIME_SET         0x000fffff
-#define PM_RSTC_WRCFG_CLR        0xffffffcf
-#define PM_RSTC_WRCFG_SET        0x00000030
-#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
-#define PM_RSTC_RESET            0x00000102
-
-#endif//_ROSE_K_P_POWER_H
-
-/* Copyright (C) 2020 Aaron Alef */
\ No newline at end of file
diff --git a/bulb/include/kernel/peripherals/timer.h b/bulb/include/kernel/peripherals/timer.h
deleted file mode 100644
index ae3bf7f..0000000
--- a/bulb/include/kernel/peripherals/timer.h
+++ /dev/null
@@ -1,19 +0,0 @@
-#ifndef _ROSE_K_P_TIMER_H
-#define _ROSE_K_P_TIMER_H
-
-#include "kernel/peripherals/base.h"
-
-#define TIMER_CS  (PBASE + 0x00003000)
-#define TIMER_CLO (PBASE + 0x00003004)
-#define TIMER_CHI (PBASE + 0x00003008)
-#define TIMER_C0  (PBASE + 0x0000300C)
-#define TIMER_C1  (PBASE + 0x00003010)
-#define TIMER_C2  (PBASE + 0x00003014)
-#define TIMER_C3  (PBASE + 0x00003018)
-
-#define TIMER_CS_M0 (1 << 0)
-#define TIMER_CS_M1 (1 << 1)
-#define TIMER_CS_M2 (1 << 2)
-#define TIMER_CS_M3 (1 << 3)
-
-#endif /*_ROSE_K_P_TIMER_H */
diff --git a/bulb/include/kernel/power.h b/bulb/include/kernel/power.h
deleted file mode 100644
index 031db9c..0000000
--- a/bulb/include/kernel/power.h
+++ /dev/null
@@ -1,14 +0,0 @@
-#ifndef _ROSE_K_POWER_H
-#define _ROSE_K_POWER_H
-
-#include "common/stdbool.h"
-#include "common/utils.h"
-#include "kernel/peripherals/power.h"
-
-// power off (timeout / 16 in seconds?)
-void poweroff (unsigned int timeout, bool block);
-
-// reboot (timeout / 16 in seconds?)
-void reboot (unsigned int timeout, bool block);
-
-#endif//_ROSE_K_POWER_H
\ No newline at end of file
diff --git a/bulb/include/kernel/timer.h b/bulb/include/kernel/timer.h
deleted file mode 100644
index f5cd0b8..0000000
--- a/bulb/include/kernel/timer.h
+++ /dev/null
@@ -1,8 +0,0 @@
-#ifndef _ROSE_K_TIMER_H
-#define _ROSE_K_TIMER_H
-
-void timer_init (void);
-
-void handle_timer_irq (void);
-
-#endif /*_ROSE_K_TIMER_H */
diff --git a/bulb/src/common/debug.c b/bulb/src/common/debug.c
deleted file mode 100644
index 4a65209..0000000
--- a/bulb/src/common/debug.c
+++ /dev/null
@@ -1,29 +0,0 @@
-#include "common/debug.h"
-
-void print_hex (unsigned char dec) {
-    char fst = dec / 16;
-    char snd = dec % 16;
-    fst      = (fst > 9) ? 'A' + fst - 10 : '0' + fst;
-    snd      = (snd > 9) ? 'A' + snd - 10 : '0' + snd;
-    printf ("%c%c ", fst, snd);
-}
-
-void hex_dump (byte_t * array) {
-    for (int i = 0; i < *(unsigned int *) array;) {
-        i += 4;
-        for (int j = 1; j <= 4; j++) {
-            print_hex (array[i - j]);
-        }
-        printf (" ");
-        if (!(i % 32))
-            printf ("\r\n");
-    }
-    printf ("\r\n");
-}
-
-void int_dump (unsigned int * array) {
-    for (int i = 0; i < *array / 4; i++) {
-        printf ("%d ", array[i]);
-    }
-    printf ("\r\n");
-}
diff --git a/bulb/src/common/font.c b/bulb/src/common/font.c
deleted file mode 100644
index 8e61da3..0000000
--- a/bulb/src/common/font.c
+++ /dev/null
@@ -1,203 +0,0 @@
-#include "common/font.h"
-
-/* From https://github.com/dhepper/font8x8/blob/master/font8x8_block.h */
-const unsigned long long int * font (int c) {
-    static const char f[128][FONT_SIZE] = {
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0000 (nul)
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0001
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0002
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0003
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0004
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0005
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0006
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0007
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0008
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0009
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000A
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000B
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000C
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000D
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000E
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+000F
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0010
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0011
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0012
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0013
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0014
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0015
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0016
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0017
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0018
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0019
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001A
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001B
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001C
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001D
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001E
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+001F
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0020 (space)
-            {0x18, 0x3C, 0x3C, 0x18, 0x18, 0x00, 0x18, 0x00},// U+0021 (!)
-            {0x36, 0x36, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0022 (")
-            {0x36, 0x36, 0x7F, 0x36, 0x7F, 0x36, 0x36, 0x00},// U+0023 (#)
-            {0x0C, 0x3E, 0x03, 0x1E, 0x30, 0x1F, 0x0C, 0x00},// U+0024 ($)
-            {0x00, 0x63, 0x33, 0x18, 0x0C, 0x66, 0x63, 0x00},// U+0025 (%)
-            {0x1C, 0x36, 0x1C, 0x6E, 0x3B, 0x33, 0x6E, 0x00},// U+0026 (&)
-            {0x06, 0x06, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0027 (')
-            {0x18, 0x0C, 0x06, 0x06, 0x06, 0x0C, 0x18, 0x00},// U+0028 (()
-            {0x06, 0x0C, 0x18, 0x18, 0x18, 0x0C, 0x06, 0x00},// U+0029 ())
-            {0x00, 0x66, 0x3C, 0xFF, 0x3C, 0x66, 0x00, 0x00},// U+002A (*)
-            {0x00, 0x0C, 0x0C, 0x3F, 0x0C, 0x0C, 0x00, 0x00},// U+002B (+)
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x0C, 0x06},// U+002C (,)
-            {0x00, 0x00, 0x00, 0x3F, 0x00, 0x00, 0x00, 0x00},// U+002D (-)
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x0C, 0x00},// U+002E (.)
-            {0x60, 0x30, 0x18, 0x0C, 0x06, 0x03, 0x01, 0x00},// U+002F (/)
-            {0x3E, 0x63, 0x73, 0x7B, 0x6F, 0x67, 0x3E, 0x00},// U+0030 (0)
-            {0x0C, 0x0E, 0x0C, 0x0C, 0x0C, 0x0C, 0x3F, 0x00},// U+0031 (1)
-            {0x1E, 0x33, 0x30, 0x1C, 0x06, 0x33, 0x3F, 0x00},// U+0032 (2)
-            {0x1E, 0x33, 0x30, 0x1C, 0x30, 0x33, 0x1E, 0x00},// U+0033 (3)
-            {0x38, 0x3C, 0x36, 0x33, 0x7F, 0x30, 0x78, 0x00},// U+0034 (4)
-            {0x3F, 0x03, 0x1F, 0x30, 0x30, 0x33, 0x1E, 0x00},// U+0035 (5)
-            {0x1C, 0x06, 0x03, 0x1F, 0x33, 0x33, 0x1E, 0x00},// U+0036 (6)
-            {0x3F, 0x33, 0x30, 0x18, 0x0C, 0x0C, 0x0C, 0x00},// U+0037 (7)
-            {0x1E, 0x33, 0x33, 0x1E, 0x33, 0x33, 0x1E, 0x00},// U+0038 (8)
-            {0x1E, 0x33, 0x33, 0x3E, 0x30, 0x18, 0x0E, 0x00},// U+0039 (9)
-            {0x00, 0x0C, 0x0C, 0x00, 0x00, 0x0C, 0x0C, 0x00},// U+003A (:)
-            {0x00, 0x0C, 0x0C, 0x00, 0x00, 0x0C, 0x0C, 0x06},// U+003B (//)
-            {0x18, 0x0C, 0x06, 0x03, 0x06, 0x0C, 0x18, 0x00},// U+003C (<)
-            {0x00, 0x00, 0x3F, 0x00, 0x00, 0x3F, 0x00, 0x00},// U+003D (=)
-            {0x06, 0x0C, 0x18, 0x30, 0x18, 0x0C, 0x06, 0x00},// U+003E (>)
-            {0x1E, 0x33, 0x30, 0x18, 0x0C, 0x00, 0x0C, 0x00},// U+003F (?)
-            {0x3E, 0x63, 0x7B, 0x7B, 0x7B, 0x03, 0x1E, 0x00},// U+0040 (@)
-            {0x0C, 0x1E, 0x33, 0x33, 0x3F, 0x33, 0x33, 0x00},// U+0041 (A)
-            {0x3F, 0x66, 0x66, 0x3E, 0x66, 0x66, 0x3F, 0x00},// U+0042 (B)
-            {0x3C, 0x66, 0x03, 0x03, 0x03, 0x66, 0x3C, 0x00},// U+0043 (C)
-            {0x1F, 0x36, 0x66, 0x66, 0x66, 0x36, 0x1F, 0x00},// U+0044 (D)
-            {0x7F, 0x46, 0x16, 0x1E, 0x16, 0x46, 0x7F, 0x00},// U+0045 (E)
-            {0x7F, 0x46, 0x16, 0x1E, 0x16, 0x06, 0x0F, 0x00},// U+0046 (F)
-            {0x3C, 0x66, 0x03, 0x03, 0x73, 0x66, 0x7C, 0x00},// U+0047 (G)
-            {0x33, 0x33, 0x33, 0x3F, 0x33, 0x33, 0x33, 0x00},// U+0048 (H)
-            {0x1E, 0x0C, 0x0C, 0x0C, 0x0C, 0x0C, 0x1E, 0x00},// U+0049 (I)
-            {0x78, 0x30, 0x30, 0x30, 0x33, 0x33, 0x1E, 0x00},// U+004A (J)
-            {0x67, 0x66, 0x36, 0x1E, 0x36, 0x66, 0x67, 0x00},// U+004B (K)
-            {0x0F, 0x06, 0x06, 0x06, 0x46, 0x66, 0x7F, 0x00},// U+004C (L)
-            {0x63, 0x77, 0x7F, 0x7F, 0x6B, 0x63, 0x63, 0x00},// U+004D (M)
-            {0x63, 0x67, 0x6F, 0x7B, 0x73, 0x63, 0x63, 0x00},// U+004E (N)
-            {0x1C, 0x36, 0x63, 0x63, 0x63, 0x36, 0x1C, 0x00},// U+004F (O)
-            {0x3F, 0x66, 0x66, 0x3E, 0x06, 0x06, 0x0F, 0x00},// U+0050 (P)
-            {0x1E, 0x33, 0x33, 0x33, 0x3B, 0x1E, 0x38, 0x00},// U+0051 (Q)
-            {0x3F, 0x66, 0x66, 0x3E, 0x36, 0x66, 0x67, 0x00},// U+0052 (R)
-            {0x1E, 0x33, 0x07, 0x0E, 0x38, 0x33, 0x1E, 0x00},// U+0053 (S)
-            {0x3F, 0x2D, 0x0C, 0x0C, 0x0C, 0x0C, 0x1E, 0x00},// U+0054 (T)
-            {0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x3F, 0x00},// U+0055 (U)
-            {0x33, 0x33, 0x33, 0x33, 0x33, 0x1E, 0x0C, 0x00},// U+0056 (V)
-            {0x63, 0x63, 0x63, 0x6B, 0x7F, 0x77, 0x63, 0x00},// U+0057 (W)
-            {0x63, 0x63, 0x36, 0x1C, 0x1C, 0x36, 0x63, 0x00},// U+0058 (X)
-            {0x33, 0x33, 0x33, 0x1E, 0x0C, 0x0C, 0x1E, 0x00},// U+0059 (Y)
-            {0x7F, 0x63, 0x31, 0x18, 0x4C, 0x66, 0x7F, 0x00},// U+005A (Z)
-            {0x1E, 0x06, 0x06, 0x06, 0x06, 0x06, 0x1E, 0x00},// U+005B ([)
-            {0x03, 0x06, 0x0C, 0x18, 0x30, 0x60, 0x40, 0x00},// U+005C (\)
-            {0x1E, 0x18, 0x18, 0x18, 0x18, 0x18, 0x1E, 0x00},// U+005D (])
-            {0x08, 0x1C, 0x36, 0x63, 0x00, 0x00, 0x00, 0x00},// U+005E (^)
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF},// U+005F (_)
-            {0x0C, 0x0C, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00},// U+0060 (`)
-            {0x00, 0x00, 0x1E, 0x30, 0x3E, 0x33, 0x6E, 0x00},// U+0061 (a)
-            {0x07, 0x06, 0x06, 0x3E, 0x66, 0x66, 0x3B, 0x00},// U+0062 (b)
-            {0x00, 0x00, 0x1E, 0x33, 0x03, 0x33, 0x1E, 0x00},// U+0063 (c)
-            {0x38, 0x30, 0x30, 0x3e, 0x33, 0x33, 0x6E, 0x00},// U+0064 (d)
-            {0x00, 0x00, 0x1E, 0x33, 0x3f, 0x03, 0x1E, 0x00},// U+0065 (e)
-            {0x1C, 0x36, 0x06, 0x0f, 0x06, 0x06, 0x0F, 0x00},// U+0066 (f)
-            {0x00, 0x00, 0x6E, 0x33, 0x33, 0x3E, 0x30, 0x1F},// U+0067 (g)
-            {0x07, 0x06, 0x36, 0x6E, 0x66, 0x66, 0x67, 0x00},// U+0068 (h)
-            {0x0C, 0x00, 0x0E, 0x0C, 0x0C, 0x0C, 0x1E, 0x00},// U+0069 (i)
-            {0x30, 0x00, 0x30, 0x30, 0x30, 0x33, 0x33, 0x1E},// U+006A (j)
-            {0x07, 0x06, 0x66, 0x36, 0x1E, 0x36, 0x67, 0x00},// U+006B (k)
-            {0x0E, 0x0C, 0x0C, 0x0C, 0x0C, 0x0C, 0x1E, 0x00},// U+006C (l)
-            {0x00, 0x00, 0x33, 0x7F, 0x7F, 0x6B, 0x63, 0x00},// U+006D (m)
-            {0x00, 0x00, 0x1F, 0x33, 0x33, 0x33, 0x33, 0x00},// U+006E (n)
-            {0x00, 0x00, 0x1E, 0x33, 0x33, 0x33, 0x1E, 0x00},// U+006F (o)
-            {0x00, 0x00, 0x3B, 0x66, 0x66, 0x3E, 0x06, 0x0F},// U+0070 (p)
-            {0x00, 0x00, 0x6E, 0x33, 0x33, 0x3E, 0x30, 0x78},// U+0071 (q)
-            {0x00, 0x00, 0x3B, 0x6E, 0x66, 0x06, 0x0F, 0x00},// U+0072 (r)
-            {0x00, 0x00, 0x3E, 0x03, 0x1E, 0x30, 0x1F, 0x00},// U+0073 (s)
-            {0x08, 0x0C, 0x3E, 0x0C, 0x0C, 0x2C, 0x18, 0x00},// U+0074 (t)
-            {0x00, 0x00, 0x33, 0x33, 0x33, 0x33, 0x6E, 0x00},// U+0075 (u)
-            {0x00, 0x00, 0x33, 0x33, 0x33, 0x1E, 0x0C, 0x00},// U+0076 (v)
-            {0x00, 0x00, 0x63, 0x6B, 0x7F, 0x7F, 0x36, 0x00},// U+0077 (w)
-            {0x00, 0x00, 0x63, 0x36, 0x1C, 0x36, 0x63, 0x00},// U+0078 (x)
-            {0x00, 0x00, 0x33, 0x33, 0x33, 0x3E, 0x30, 0x1F},// U+0079 (y)
-            {0x00, 0x00, 0x3F, 0x19, 0x0C, 0x26, 0x3F, 0x00},// U+007A (z)
-            {0x38, 0x0C, 0x0C, 0x07, 0x0C, 0x0C, 0x38, 0x00},// U+007B ({)
-            {0x18, 0x18, 0x18, 0x00, 0x18, 0x18, 0x18, 0x00},// U+007C (|)
-            {0x07, 0x0C, 0x0C, 0x38, 0x0C, 0x0C, 0x07, 0x00},// U+007D (})
-            {0x6E, 0x3B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},// U+007E (~)
-            {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00} // U+007F
-    };
-    return (unsigned long long int *) f[c];
-}
-
-void printc_location (point_t point, char c) {
-    unsigned char const * bitmap = (unsigned char const *) font (c);
-    for (int i = 0; i < FONT_SIZE; i++) {
-        for (int j = 0; j < FONT_SIZE; j++) {
-            bool is_on = bitmap[i] & (1 << j);
-
-            point_t _point;
-            for (int k = 0; k < FONT_FACTOR; k++) {
-                for (int h = 0; h < FONT_FACTOR; h++) {
-                    _point.x = point.x + j * FONT_FACTOR + k;
-                    _point.y = point.y + i * FONT_FACTOR + h;
-                    drawpx (_point, is_on ? font_fg : font_bg);
-                }
-            }
-        }
-    }
-}
-
-void printc (char c) {
-    // Handle special characters, print otherwise
-    switch (c) {
-        case '\r':// Reset cursor to beginning of line
-            cursor.x = 0;
-            break;
-        case '\n':// Move cursor to next line
-            cursor.y += FONT_REAL_HEIGHT;
-            break;
-        case '\t':// Print minimum one space, then align forwards to tab grid
-            cursor.x += FONT_TAB_REAL_WIDTH - cursor.x % (FONT_TAB_REAL_WIDTH);
-            break;
-        default:// Print character and update cursor
-            // TODO dynamically deal with unprintable characters (i.e., check if bitmap is all '0')
-            printc_location (cursor, c);
-            cursor.x += FONT_REAL_WIDTH;
-    }
-
-    // If next printed char overflowed screen width move cursor to beginning of next line
-    if (cursor.x + FONT_REAL_WIDTH >= get_max_width ()) {
-        cursor.x = 0;
-        cursor.y += FONT_REAL_HEIGHT;
-    }
-    // If next line would overflow screen height (ignoring line spacing) move to beginning of screen
-    if (cursor.y + FONT_REAL_WIDTH - FONT_SPACING >= get_max_height ()) {
-#ifndef FONT_SCROLLBACK
-        cursor.y -= FONT_SB_LINES * FONT_REAL_HEIGHT;
-        unsigned int remove_size = FONT_SB_LINES * FONT_REAL_HEIGHT * get_fb_info ()->pitch;
-        unsigned int scroll_size = get_fb_info ()->fb_size - remove_size;
-        memcpy ((ptr_t) get_fb (), (ptr_t) get_fb () + remove_size, scroll_size);
-        memzero ((ptr_t) get_fb () + scroll_size, remove_size);
-#else
-        // TODO clear framebuffer here...?
-        cursor.y = 0;
-#endif
-    }
-}
-
-void font_set_normal (void) {
-    font_fg = font_normal_fg;
-}
-void font_set_error (void) {
-    font_fg = font_error_fg;
-}
-
-void putc_screen (void * p, char c) {
-    printc (c);
-}
diff --git a/bulb/src/common/gpu.c b/bulb/src/common/gpu.c
deleted file mode 100644
index 4b376da..0000000
--- a/bulb/src/common/gpu.c
+++ /dev/null
@@ -1,137 +0,0 @@
-#include "common/gpu.h"
-
-bool init_gpu () {
-    {                           // First message: read physical dimensions
-        int c               = 0;// Message size; increment while we write
-        gpu_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
-
-        gpu_msg_buffer[++c] = 0x00040003;// Tag to get physical display width / height
-        gpu_msg_buffer[++c] = 8;         // Size of value buffer
-        gpu_msg_buffer[++c] = 0;         // Response & value buffer size written will be written here
-        gpu_msg_buffer[++c] = 0;         // Get physical screen width    |  Overwritten by actual width
-        gpu_msg_buffer[++c] = 0;         // Get physical screen height   |  Overwritten by actual height
-        gpu_msg_buffer[++c] = 0;         // End tag
-
-        gpu_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
-
-        // If reading physical screen dimension fails exit function
-        if (! mailbox_request (gpu_msg_buffer, PROPERTY_ARM_VC))
-            return false;
-    }
-    {                           // Second message: request frame buffer
-        int c               = 0;// Message size; increment while we write
-        gpu_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
-
-#ifdef GPU_OVERRIDE_PHYSICAL_SCREEN             // If this is set, update physical /virtual dimensions based on constants
-        gpu_msg_buffer[++c]  = 0x00048003;      // Tag to set virtual display width / height
-        gpu_msg_buffer[++c]  = 8;               // Size of value buffer
-        gpu_msg_buffer[++c]  = 0;               // Response & value buffer size written will be written here
-        gpu_msg_buffer[++c]  = GPU_SCREEN_WIDTH;// Set virtual screen width     |  Overwritten by actual virtual width
-        int index_gpu_width  = c;
-        gpu_msg_buffer[++c]  = GPU_SCREEN_HEIGHT;// Set virtual screen height    |  Overwritten by actual virtual height
-        int index_gpu_height = c;
-
-        gpu_msg_buffer[++c] = 0x00048004;       // Tag to set virtual display width / height
-        gpu_msg_buffer[++c] = 8;                // Size of value buffer
-        gpu_msg_buffer[++c] = 0;                // Response & value buffer size written will be written here
-        gpu_msg_buffer[++c] = GPU_VIRTUAL_WIDTH;// Set virtual screen width     |  Overwritten by actual virtual width
-        int index_width     = c;
-        gpu_msg_buffer[++c] = GPU_VIRTUAL_HEIGHT;// Set virtual screen height    |  Overwritten by actual virtual height
-        int index_height    = c;
-#else
-        gpu_msg_buffer[++c] = 0x00048004;// Tag to set virtual display width / height
-        gpu_msg_buffer[++c] = 8;         // Size of value buffer
-        gpu_msg_buffer[++c] = 0;         // Response & value buffer size written will be written here
-        gpu_msg_buffer[++c];             //GPU_SCREEN_WIDTH;      // Reuse previous width         |  Overwritten by actual virtual width
-        int index_width = c;
-        gpu_msg_buffer[++c];//GPU_SCREEN_HEIGHT;     // Reuse previous height        |  Overwritten by actual virtual height
-        int index_height = c;
-#endif
-
-        gpu_msg_buffer[++c] = 0x00048005;      // Tag to set pixel depth
-        gpu_msg_buffer[++c] = 4;               // Size of value buffer
-        gpu_msg_buffer[++c] = 0;               // Response & value buffer size written will be written here
-        gpu_msg_buffer[++c] = GPU_COLOUR_DEPTH;// Set colour depth             |  Overwritten by actual colour depth
-
-        gpu_msg_buffer[++c]   = 0x00040001;// Tag to allocate framebuffer
-        gpu_msg_buffer[++c]   = 8;         // Size of value buffer
-        gpu_msg_buffer[++c]   = 0;         // Response & value buffer size will be written here
-        gpu_msg_buffer[++c]   = 16;        // Buffer alignment             |  Overwritten by pointer to framebuffer
-        int index_framebuffer = c;
-        gpu_msg_buffer[++c]   = 0;// Unused - will be overwritten |  Overwritten by size of framebuffer
-        int index_fb_size     = c;
-
-        gpu_msg_buffer[++c] = 0;// End tag
-        gpu_msg_buffer[++c] = 0;// Padding
-        gpu_msg_buffer[++c] = 0;// Padding
-        gpu_msg_buffer[++c] = 0;// Padding
-
-        gpu_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
-
-        // If message failed exit
-        if (! mailbox_request (gpu_msg_buffer, PROPERTY_ARM_VC))
-            return false;
-
-        // Since message succeeded, update frame buffer and its size
-        fb_info.fb      = (color_t *) (long) (gpu_msg_buffer[index_framebuffer] & VC_SDRAM_OFFSET);
-        fb_info.fb_size = gpu_msg_buffer[index_fb_size];
-
-        // printf ("PHY_WIDTH: %d, PHY_HEIGHT: %d, VIRT_WIDTH: %d, VIRT_HEIGHT: %d\n\r", gpu_msg_buffer[index_gpu_width], gpu_msg_buffer[index_gpu_height], gpu_msg_buffer[index_width], gpu_msg_buffer[index_height]);
-
-        fb_info.virtual_width  = gpu_msg_buffer[index_width];
-        fb_info.virtual_height = gpu_msg_buffer[index_height];
-    }
-    {                           // Third message: read pitch (in bytes per line)
-        int c               = 0;// Message size; increment while we write
-        gpu_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
-
-        gpu_msg_buffer[++c] = 0x00040008;// Tag to get pitch
-        gpu_msg_buffer[++c] = 4;         // Size of value buffer
-        gpu_msg_buffer[++c] = 0;         // Response & value buffer size written will be written here
-        gpu_msg_buffer[++c] = 0;         // Pitch will be written here
-        int index_pitch     = c;
-
-        gpu_msg_buffer[++c] = 0;// End tag
-        gpu_msg_buffer[++c] = 0;// Padding
-
-        gpu_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
-
-        // If message failed exit
-        if (! mailbox_request (gpu_msg_buffer, PROPERTY_ARM_VC))
-            return false;
-
-        // Else write pitch appropriately
-        fb_info.pitch = gpu_msg_buffer[index_pitch];
-    }
-    return true;
-}
-
-color_t * get_fb () {
-    return fb_info.fb;
-}
-
-fb_info_t const * get_fb_info () {
-    return &fb_info;
-}
-
-bool blank_screen (bool blank) {
-    int c               = 0;// Message size; increment while we write
-    gpu_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
-
-    gpu_msg_buffer[++c] = 0x00040002;// Tag to blank screen
-    gpu_msg_buffer[++c] = 4;         // Size of value buffer
-    gpu_msg_buffer[++c] = 0;         //
-    gpu_msg_buffer[++c] = blank;     // On or off
-
-    gpu_msg_buffer[++c] = 0;// End tag
-    gpu_msg_buffer[++c] = 0;// Padding
-
-    gpu_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
-
-    return mailbox_request (gpu_msg_buffer, PROPERTY_ARM_VC);
-}
-
-bool toggle_blank_screen (void) {
-    static bool is_blank = false;
-    blank_screen (is_blank = ! is_blank);
-}
\ No newline at end of file
diff --git a/bulb/src/common/printf.c b/bulb/src/common/printf.c
deleted file mode 100644
index 059ee24..0000000
--- a/bulb/src/common/printf.c
+++ /dev/null
@@ -1,243 +0,0 @@
-/*
-File: printf.c
-
-Copyright (C) 2004  Kustaa Nyholm
-
-This library is free software; you can redistribute it and/or
-modify it under the terms of the GNU Lesser General Public
-License as published by the Free Software Foundation; either
-version 2.1 of the License, or (at your option) any later version.
-
-This library is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-Lesser General Public License for more details.
-
-You should have received a copy of the GNU Lesser General Public
-License along with this library; if not, write to the Free Software
-Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-*/
-
-#include "common/printf.h"
-
-typedef void (*putcf) (void *, char);
-
-static putcf  stdout_putf;
-static void * stdout_putp;
-
-
-#ifdef PRINTF_LONG_SUPPORT
-
-static void uli2a (unsigned long int num, unsigned int base, int uc, char * bf) {
-    int          n = 0;
-    unsigned int d = 1;
-    while (num / d >= base)
-        d *= base;
-    while (d != 0) {
-        int dgt = num / d;
-        num %= d;
-        d /= base;
-        if (n || dgt > 0 || d == 0) {
-            *bf++ = dgt + (dgt < 10 ? '0' : (uc ? 'A' : 'a') - 10);
-            ++n;
-        }
-    }
-    *bf = 0;
-}
-
-static void li2a (long num, char * bf) {
-    if (num < 0) {
-        num   = -num;
-        *bf++ = '-';
-    }
-    uli2a (num, 10, 0, bf);
-}
-
-#endif
-
-static void ui2a (unsigned int num, unsigned int base, int uc, char * bf) {
-    int          n = 0;
-    unsigned int d = 1;
-    while (num / d >= base)
-        d *= base;
-    while (d != 0) {
-        int dgt = num / d;
-        num %= d;
-        d /= base;
-        if (n || dgt > 0 || d == 0) {
-            *bf++ = dgt + (dgt < 10 ? '0' : (uc ? 'A' : 'a') - 10);
-            ++n;
-        }
-    }
-    *bf = 0;
-}
-
-static void i2a (int num, char * bf) {
-    if (num < 0) {
-        num   = -num;
-        *bf++ = '-';
-    }
-    ui2a (num, 10, 0, bf);
-}
-
-static int a2d (char ch) {
-    if (ch >= '0' && ch <= '9') {
-        return ch - '0';
-    } else if (ch >= 'a' && ch <= 'f') {
-        return ch - 'a' + 10;
-    } else if (ch >= 'A' && ch <= 'F') {
-        return ch - 'A' + 10;
-    } else {
-        return -1;
-    }
-}
-
-static char a2i (char ch, char ** src, int base, int * nump) {
-    char * p   = *src;
-    int    num = 0;
-    int    digit;
-    while ((digit = a2d (ch)) >= 0) {
-        if (digit > base)
-            break;
-        num = num * base + digit;
-        ch  = *p++;
-    }
-    *src  = p;
-    *nump = num;
-    return ch;
-}
-
-static void putchw (void * putp, putcf putf, int n, char z, char * bf) {
-    char   fc = z ? '0' : ' ';
-    char   ch;
-    char * p = bf;
-    while (*p++ && n > 0)
-        n--;
-    while (n-- > 0)
-        putf (putp, fc);
-    while ((ch = *bf++))
-        putf (putp, ch);
-}
-
-void tfp_format (void * putp, putcf putf, char * fmt, va_list va) {
-    char bf[12];
-
-    char ch;
-
-
-    while ((ch = *(fmt++))) {
-        if (ch != '%') {
-            putf (putp, ch);
-        } else {
-            char lz = 0;
-#ifdef PRINTF_LONG_SUPPORT
-            char lng = 0;
-#endif
-            int w = 0;
-            ch    = *(fmt++);
-            if (ch == '0') {
-                ch = *(fmt++);
-                lz = 1;
-            }
-            if (ch >= '0' && ch <= '9') {
-                ch = a2i (ch, &fmt, 10, &w);
-            }
-#ifdef PRINTF_LONG_SUPPORT
-            if (ch == 'l') {
-                ch  = *(fmt++);
-                lng = 1;
-            }
-#endif
-            switch (ch) {
-                case 0:
-                    goto abort;
-                case 'u': {
-#ifdef PRINTF_LONG_SUPPORT
-                    if (lng)
-                        uli2a (va_arg (va, unsigned long int), 10, 0, bf);
-                    else
-#endif
-                    ui2a (va_arg (va,
-                                  unsigned int), 10, 0, bf);
-                    putchw (putp, putf, w, lz, bf);
-                    break;
-                }
-                case 'd': {
-#ifdef PRINTF_LONG_SUPPORT
-                    if (lng)
-                        li2a (va_arg (va, unsigned long int), bf);
-                    else
-#endif
-                    i2a (va_arg (va,
-                                 int), bf);
-                    putchw (putp, putf, w, lz, bf);
-                    break;
-                }
-                case 'x':
-                case 'X':
-#ifdef PRINTF_LONG_SUPPORT
-                    if (lng)
-                        uli2a (va_arg (va, unsigned long int), 16, (ch == 'X'), bf);
-                    else
-#endif
-                    ui2a (va_arg (va,
-                                  unsigned int), 16, (ch == 'X'), bf);
-                    putchw (putp, putf, w, lz, bf);
-                    break;
-                case 'c' :
-                    putf (putp, (char) (va_arg (va,
-                                                int)));
-                    break;
-                case 's' :
-                    putchw (putp, putf, w, 0, va_arg (va,
-                                                      char*));
-                    break;
-                case 'p':
-                case 'P':
-                    putf (putp, '0');
-                    putf (putp, 'x');
-#ifdef PRINTF_LONG_SUPPORT
-                    if (lng)
-                        uli2a (va_arg (va, unsigned long int), 16, (ch == 'P'), bf);
-                    else
-#endif
-                    ui2a (va_arg (va,
-                                  unsigned int), 16, (ch == 'P'), bf);
-                    putchw (putp, putf, w, lz, bf);
-                    break;
-                case '%':
-                    putf (putp, ch);
-                default:
-                    break;
-            }
-        }
-    }
-abort:;
-}
-
-
-void init_printf (void * putp, void (*putf) (void *, char)) {
-    stdout_putf = putf;
-    stdout_putp = putp;
-}
-
-void tfp_printf (char * fmt, ...) {
-    va_list va;
-    va_start (va, fmt);
-    tfp_format (stdout_putp, stdout_putf, fmt, va);
-    va_end (va);
-}
-
-static void putcp (void * p, char c) {
-    *(*((char **) p))++ = c;
-}
-
-
-void tfp_sprintf (char * s, char * fmt, ...) {
-    va_list va;
-    va_start (va, fmt);
-    tfp_format (&s, putcp, fmt, va);
-    putcp (&s, 0);
-    va_end (va);
-}
diff --git a/bulb/src/common/screen.c b/bulb/src/common/screen.c
deleted file mode 100644
index b09764d..0000000
--- a/bulb/src/common/screen.c
+++ /dev/null
@@ -1,14 +0,0 @@
-#include "common/screen.h"
-
-void drawpx (point_t p, color_t color) {
-    unsigned long int location = p.y * (get_fb_info ()->pitch) / sizeof (color_t) + p.x;
-    get_fb ()[location]        = color;
-};
-
-short get_max_width () {
-    return get_fb_info ()->virtual_width - 1;
-}
-
-short get_max_height () {
-    return get_fb_info ()->virtual_height - 1;
-}
diff --git a/bulb/src/common/status_led.c b/bulb/src/common/status_led.c
deleted file mode 100644
index b8b1b03..0000000
--- a/bulb/src/common/status_led.c
+++ /dev/null
@@ -1,55 +0,0 @@
-#include "common/status_led.h"
-
-bool get_led (int pin) {
-    // Try to read ACT LED state
-    int c               = 0;// Message size; increment while we write
-    led_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
-
-    led_msg_buffer[++c] = 0x00030041;// Tag to get ACT LED state
-    led_msg_buffer[++c] = 8;         // Size of value buffer
-    led_msg_buffer[++c] = 0;         // Response & value buffer size written will be written here
-    led_msg_buffer[++c] = pin;       //
-    led_msg_buffer[++c] = 0;         //
-    int index_led       = c;
-
-    led_msg_buffer[++c] = 0;// End tag
-
-    led_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
-
-    if (! mailbox_request (led_msg_buffer, PROPERTY_ARM_VC)) {
-        printf ("ERROR\r\n");
-    };
-    return ! led_msg_buffer[index_led];
-}
-
-/**
- * Change LED state
- * Pins:
- *  - Power LED: 130 (0 to turn on and 1 to turn off)
- *  - ACT LED: 42 (1 to turn on and 0 to turn off)
-**/
-void set_led (bool status, int pin) {
-    // Try to read ACT LED state
-    int c               = 0;// Message size; increment while we write
-    led_msg_buffer[++c] = 0;// Response - will be 0x80000000 for SUCCESS or 0x80000001 for FAILURE
-
-    led_msg_buffer[++c] = 0x00038041;// Tag to get ACT LED state
-    led_msg_buffer[++c] = 8;         // Size of value buffer
-    led_msg_buffer[++c] = 0;         // Response & value buffer size written will be written here
-    led_msg_buffer[++c] = pin;
-    led_msg_buffer[++c] = status;
-
-    led_msg_buffer[++c] = 0;// End tag
-
-    led_msg_buffer[0] = (4 * ++c);// Write message size at the beginning of the buffer
-
-    if (! mailbox_request (led_msg_buffer, PROPERTY_ARM_VC)) {
-        printf ("ERROR\r\n");
-    };
-}
-
-bool toggle_led (int pin) {
-    bool status = get_led (pin);
-    set_led (status, pin);
-    return status;
-}
diff --git a/bulb/src/common/utils.S b/bulb/src/common/utils.S
deleted file mode 100644
index 44be485..0000000
--- a/bulb/src/common/utils.S
+++ /dev/null
@@ -1,21 +0,0 @@
-.globl get_el
-get_el:
-	mrs x0, CurrentEL
-	lsr x0, x0, #2
-	ret
-
-.globl put32
-put32:
-	str w1,[x0]
-	ret
-
-.globl get32
-get32:
-	ldr w0,[x0]
-	ret
-
-.globl delay
-delay:
-	subs x0, x0, #1
-	bne delay
-	ret
diff --git a/bulb/src/config.txt b/bulb/src/config.txt
deleted file mode 100644
index 1cb4eed..0000000
--- a/bulb/src/config.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-enable_uart=1
-dtparam=watchdog=on
diff --git a/bulb/src/kernel/boot.S b/bulb/src/kernel/boot.S
deleted file mode 100644
index 14bc88a..0000000
--- a/bulb/src/kernel/boot.S
+++ /dev/null
@@ -1,52 +0,0 @@
-#include "kernel/arm/sysregs.h"
-
-#include "kernel/mm.h"
-
-.section ".text.boot"
-
-.globl _start
-_start:
-	mrs	x0, mpidr_el1
-	and	x0, x0,#0xFF		// Check processor id
-	cbz	x0, init_bss		// Hang for all non-primary CPU
-
-	wfe
-
-	b	master
-
-init_bss:
-	adr	x0, __bss_start
-	adr	x1, __bss_end
-	sub	x1, x1, x0
-	bl	memzero
-
-    b move_to_el1
-
-move_to_el1:
-	ldr	x0, =SCTLR_VALUE_MMU_DISABLED
-	msr	sctlr_el1, x0
-
-	ldr	x0, =HCR_VALUE
-	msr	hcr_el2, x0
-
-	ldr	x0, =SPSR_VALUE
-	msr	spsr_el2, x0
-
-	adr	x0, master
-	msr	elr_el2, x0
-
-	eret
-
-master:
-	mrs	x0, mpidr_el1
-	and	x0, x0, #0xFF
-	mov	x1, #SECTION_SIZE
-	mul	x1, x1, x0
-	add	x1, x1, #LOW_MEMORY
-	mov	sp, x1
-
-	bl	kernel_main
-
-proc_hang:
-	b	proc_hang
-
diff --git a/bulb/src/kernel/entry.S b/bulb/src/kernel/entry.S
deleted file mode 100644
index dcbbce8..0000000
--- a/bulb/src/kernel/entry.S
+++ /dev/null
@@ -1,181 +0,0 @@
-#include "kernel/arm/sysregs.h"
-#include "kernel/entry.h"
-#include "kernel/mmu.h"
-
-	.macro handle_invalid_entry el, type
-	kernel_entry \el
-	mov	x0, #\type
-	mrs	x1, esr_el1
-	mrs	x2, elr_el1
-	bl	show_invalid_entry_message
-	b	err_hang
-	.endm
-
-	.macro	ventry	label
-	.align	7
-	b	\label
-	.endm
-
-	.macro	kernel_entry, el
-	sub	sp, sp, #S_FRAME_SIZE
-	stp	x0, x1, [sp, #16 * 0]
-	stp	x2, x3, [sp, #16 * 1]
-	stp	x4, x5, [sp, #16 * 2]
-	stp	x6, x7, [sp, #16 * 3]
-	stp	x8, x9, [sp, #16 * 4]
-	stp	x10, x11, [sp, #16 * 5]
-	stp	x12, x13, [sp, #16 * 6]
-	stp	x14, x15, [sp, #16 * 7]
-	stp	x16, x17, [sp, #16 * 8]
-	stp	x18, x19, [sp, #16 * 9]
-	stp	x20, x21, [sp, #16 * 10]
-	stp	x22, x23, [sp, #16 * 11]
-	stp	x24, x25, [sp, #16 * 12]
-	stp	x26, x27, [sp, #16 * 13]
-	stp	x28, x29, [sp, #16 * 14]
-
-	.if	\el == 0
-	mrs	x21, sp_el0
-	.else
-	add	x21, sp, #S_FRAME_SIZE
-	.endif /* \el == 0 */
-
-	mrs	x22, elr_el1
-	mrs	x23, spsr_el1
-
-	stp	x30, x21, [sp, #16 * 15]
-	stp	x22, x23, [sp, #16 * 16]
-	.endm
-
-	.macro	kernel_exit, el
-	ldp	x22, x23, [sp, #16 * 16]
-	ldp	x30, x21, [sp, #16 * 15]
-
-	.if	\el == 0
-	msr	sp_el0, x21
-	.endif /* \el == 0 */
-
-	msr	elr_el1, x22
-	msr	spsr_el1, x23
-
-
-	ldp	x0, x1, [sp, #16 * 0]
-	ldp	x2, x3, [sp, #16 * 1]
-	ldp	x4, x5, [sp, #16 * 2]
-	ldp	x6, x7, [sp, #16 * 3]
-	ldp	x8, x9, [sp, #16 * 4]
-	ldp	x10, x11, [sp, #16 * 5]
-	ldp	x12, x13, [sp, #16 * 6]
-	ldp	x14, x15, [sp, #16 * 7]
-	ldp	x16, x17, [sp, #16 * 8]
-	ldp	x18, x19, [sp, #16 * 9]
-	ldp	x20, x21, [sp, #16 * 10]
-	ldp	x22, x23, [sp, #16 * 11]
-	ldp	x24, x25, [sp, #16 * 12]
-	ldp	x26, x27, [sp, #16 * 13]
-	ldp	x28, x29, [sp, #16 * 14]
-	add	sp, sp, #S_FRAME_SIZE
-	eret
-	.endm
-
-
-/*
- * Exception vectors.
- */
-.align	11
-.globl vectors
-vectors:
-	ventry	sync_invalid_el1t			// Synchronous EL1t
-	ventry	irq_invalid_el1t			// IRQ EL1t
-	ventry	fiq_invalid_el1t			// FIQ EL1t
-	ventry	error_invalid_el1t			// Error EL1t
-
-    ventry	el0_sync			// Synchronous EL1h
-	ventry	el1_irq					    // IRQ EL1h
-	ventry	fiq_invalid_el1h			// FIQ EL1h
-	ventry	error_invalid_el1h			// Error EL1h
-
-	ventry	el0_sync				    // Synchronous 64-bit EL0
-	ventry	el0_irq					    // IRQ 64-bit EL0
-	ventry	fiq_invalid_el0_64			// FIQ 64-bit EL0
-	ventry	error_invalid_el0_64		// Error 64-bit EL0
-
-	ventry	sync_invalid_el0_32			// Synchronous 32-bit EL0
-	ventry	irq_invalid_el0_32			// IRQ 32-bit EL0
-	ventry	fiq_invalid_el0_32			// FIQ 32-bit EL0
-	ventry	error_invalid_el0_32		// Error 32-bit EL0
-
-sync_invalid_el1t:
-	handle_invalid_entry 1,  SYNC_INVALID_EL1t
-
-irq_invalid_el1t:
-	handle_invalid_entry  1, IRQ_INVALID_EL1t
-
-fiq_invalid_el1t:
-	handle_invalid_entry  1, FIQ_INVALID_EL1t
-
-error_invalid_el1t:
-	handle_invalid_entry  1, ERROR_INVALID_EL1t
-
-sync_invalid_el1h:
-	handle_invalid_entry 1, SYNC_INVALID_EL1h
-
-fiq_invalid_el1h:
-	handle_invalid_entry  1, FIQ_INVALID_EL1h
-
-error_invalid_el1h:
-	handle_invalid_entry  1, ERROR_INVALID_EL1h
-
-fiq_invalid_el0_64:
-	handle_invalid_entry  0, FIQ_INVALID_EL0_64
-
-error_invalid_el0_64:
-	handle_invalid_entry  0, ERROR_INVALID_EL0_64
-
-sync_invalid_el0_32:
-	handle_invalid_entry  0, SYNC_INVALID_EL0_32
-
-irq_invalid_el0_32:
-	handle_invalid_entry  0, IRQ_INVALID_EL0_32
-
-fiq_invalid_el0_32:
-	handle_invalid_entry  0, FIQ_INVALID_EL0_32
-
-error_invalid_el0_32:
-	handle_invalid_entry  0, ERROR_INVALID_EL0_32
-
-el1_irq:
-	kernel_entry 1
-	bl	handle_irq
-	kernel_exit 1
-
-el0_irq:
-	kernel_entry 0
-	bl	handle_irq
-	kernel_exit 0
-
-el0_sync:
-	kernel_entry 0
-
-    mrs	x25, esr_el1
-	lsr	x24, x25, #ESR_ELx_EC_SHIFT
-	cmp x24, #ESR_ELx_EC_DABT_SAME
-	b.eq 	el1_da
-
-	handle_invalid_entry 0, SYNC_ERROR
-
-sc_nr	.req	x25					// number of system calls
-scno	.req	x26					// syscall number
-stbl	.req	x27					// syscall table pointer
-
-el1_da:
-	bl enable_irq
-	mrs x0, far_el1
-	mrs x1, esr_el1
-	bl data_abort_el1
-    bl disable_irq
-    eret
-
-.globl err_hang
-err_hang: b err_hang
-
diff --git a/bulb/src/kernel/irq.S b/bulb/src/kernel/irq.S
deleted file mode 100644
index ad54157..0000000
--- a/bulb/src/kernel/irq.S
+++ /dev/null
@@ -1,15 +0,0 @@
-.globl irq_vector_init
-irq_vector_init:
-	adr	x0, vectors		// load VBAR_EL1 with virtual
-	msr	vbar_el1, x0		// vector table address
-	ret
-
-.globl enable_irq
-enable_irq:
-	msr    daifclr, #2
-	ret
-
-.globl disable_irq
-disable_irq:
-	msr	daifset, #2
-	ret
diff --git a/bulb/src/kernel/irq.c b/bulb/src/kernel/irq.c
deleted file mode 100644
index 7ca1047..0000000
--- a/bulb/src/kernel/irq.c
+++ /dev/null
@@ -1,51 +0,0 @@
-#include "kernel/irq.h"
-
-const char * entry_error_messages[] = {
-        "SYNC_INVALID_EL1t", "IRQ_INVALID_EL1t", "FIQ_INVALID_EL1t", "ERROR_INVALID_EL1T", "SYNC_INVALID_EL1h", "IRQ_INVALID_EL1h", "FIQ_INVALID_EL1h", "ERROR_INVALID_EL1h", "SYNC_INVALID_EL0_64", "IRQ_INVALID_EL0_64", "FIQ_INVALID_EL0_64", "ERROR_INVALID_EL0_64", "SYNC_INVALID_EL0_32", "IRQ_INVALID_EL0_32", "FIQ_INVALID_EL0_32", "ERROR_INVALID_EL0_32", "SYNC_ERROR", "SYSCALL_ERROR"};
-
-void enable_interrupt (unsigned int irq) {
-    printf ("Interrupt pointer %p\r\n", irq);
-    unsigned int n              = irq / 32;
-    unsigned int offset         = irq % 32;
-    unsigned int enableRegister = GICD_ENABLE_IRQ_BASE + (4 * n);
-    printf ("EnableRegister: %x\r\n", enableRegister);
-    put32 (enableRegister, 1 << offset);
-}
-
-void assign_target (unsigned int irq, unsigned int cpu) {
-    unsigned int n              = irq / 4;
-    unsigned int targetRegister = GIC_IRQ_TARGET_BASE + (4 * n);
-    // Currently we only enter the target CPU 0
-    put32 (targetRegister, get32 (targetRegister) | (1 << 8));
-}
-
-void show_invalid_entry_message (int type, ptr_t esr, ptr_t address) {
-    printf ("Type %s, ESR: %p, address, %p\r\n", entry_error_messages[type], (void *) esr, (void *) address);
-}
-
-void enable_interrupt_controller () {
-    assign_target (SYSTEM_TIMER_IRQ_1, 0);
-    put32 (ENABLE_IRQS_1, SYSTEM_TIMER_IRQ_1
-#ifdef _ROSE_K_MINI_UART_H
-                                  | ENABLE_AUX_INT
-#endif
-    );
-    enable_interrupt (SYSTEM_TIMER_IRQ_1);
-}
-
-void handle_irq (void) {
-    unsigned int irq_ack_reg = get32 (GICC_IAR);
-    unsigned int irq1        = irq_ack_reg & 0x2FF;
-    if (irq1 & SYSTEM_TIMER_IRQ_1) {
-        put32 (GICC_EOIR, irq_ack_reg);
-        handle_timer_irq ();
-    }
-
-#ifdef _ROSE_K_MINI_UART_H
-    unsigned int irq2 = get32 (AUX_IRQ_REG);
-    if (irq2 & MINI_UART_IRQ) {
-        put32 (GICC_EOIR, irq_ack_reg);
-        handle_mini_uart_irq ();
-    }
-#endif
-}
diff --git a/bulb/src/kernel/kernel.c b/bulb/src/kernel/kernel.c
deleted file mode 100644
index 629c1a4..0000000
--- a/bulb/src/kernel/kernel.c
+++ /dev/null
@@ -1,64 +0,0 @@
-#include "kernel/mini_uart.h"
-//
-#include "common/font.h"
-#include "common/gpu.h"
-#include "common/logging.h"
-#include "common/printf.h"
-#include "common/status_led.h"
-#include "common/utils.h"
-#include "kernel/entry.h"
-#include "kernel/irq.h"
-#include "kernel/mm.h"
-#include "kernel/mmu.h"
-
-void hang (int led, int cycles) {
-    while (1) {
-        toggle_led (led);
-        delay (cycles);
-    }
-}
-
-void dual_print (void * p, char c) {
-    printc (c);
-    uart_send (c);
-}
-
-void kernel_init (void) {
-    set_led (0, POWER_LED);
-    set_led (0, STATUS_LED);
-
-    uart_init ();
-    init_printf (0, putc);
-
-    if (init_gpu ()) {
-        if (get_fb ()) {
-            font_set_normal ();
-            init_printf (0, putc_screen);
-            printf ("Frame  buffer:     %p\r\n", get_fb ());
-            printf ("Width  resolution: %d\r\n", get_fb_info ()->virtual_width);
-            printf ("Height resolution: %d\r\n", get_fb_info ()->virtual_height);
-
-            LOG ("Initialisation done");
-            ERROR ("I'm important!");
-        } else
-            hang (POWER_LED, 1000000);
-    } else
-        hang (POWER_LED, 2000000);
-    init_printf (0, dual_print);
-
-    timer_init ();
-    irq_vector_init ();
-    enable_interrupt_controller ();
-    enable_irq ();
-}
-
-void kernel_main (int processor_id) {
-    kernel_init ();
-
-    init_mmu ();
-
-    printf ("Hello, from processor %d in EL %d\r\n", processor_id, get_el ());
-    uart_send ("EVERYTHING WORKS!!!\r\n");
-
-    hang (POWER_LED, 5000000);
-}
diff --git a/bulb/src/kernel/mailbox.c b/bulb/src/kernel/mailbox.c
deleted file mode 100644
index a744c50..0000000
--- a/bulb/src/kernel/mailbox.c
+++ /dev/null
@@ -1,52 +0,0 @@
-#include "kernel/mailbox.h"
-
-bool mailbox_request (volatile unsigned int * data_ptr, channel_t channel) {
-    volatile unsigned int * buffer = data_ptr;
-
-    if (DUMP_BUFFER) {
-        LOG ("Dumping message buffer before sending:");
-        int_dump ((unsigned int *) buffer);
-        hex_dump ((byte_t *) buffer);
-    }
-
-    // 28-bit address (MSB) and 4-bit value (LSB)
-    unsigned int outgoing = ((unsigned int) ((long) data_ptr) & ~0xF) | (channel & 0xF);
-
-    // Wait until we can write
-    while (get32 (MBOX0 + MBOX_STATUS) & MBOX_WRITE_FULL)
-        ;
-
-    // Write the address of our buffer to the mailbox with the channel appended
-    put32 (MBOX0 + MBOX_WRITE, outgoing);
-
-    unsigned int incoming;
-    while (1) {
-        // Is there a reply?
-        while (get32 (MBOX0 + MBOX_STATUS) & MBOX_READ_EMPTY)
-            ;
-
-        incoming = get32 (MBOX0 + MBOX_READ);
-
-        // Is it a reply to our message?
-        if (outgoing == incoming) {
-            if (buffer[1] != MBOX_SUCCESS) {
-                if (DUMP_BUFFER) {
-                    LOG ("Dumping failed message buffer:");
-                    int_dump ((unsigned int *) buffer);
-                    hex_dump ((byte_t *) buffer);
-                }
-
-                return false;
-            }
-            break;
-        }
-    }
-
-    if (DUMP_BUFFER) {
-        LOG ("Dumping successful message buffer:");
-        int_dump ((unsigned int *) buffer);
-        hex_dump ((byte_t *) buffer);
-    }
-
-    return true;
-}
diff --git a/bulb/src/kernel/mini_uart.c b/bulb/src/kernel/mini_uart.c
deleted file mode 100644
index 64b005e..0000000
--- a/bulb/src/kernel/mini_uart.c
+++ /dev/null
@@ -1,87 +0,0 @@
-#include "kernel/mini_uart.h"
-
-void mini_uart_send (char c) {
-    while (1) {
-        if (get32 (AUX_MU_LSR_REG) & 0x20) {
-            break;
-        }
-    }
-    put32 (AUX_MU_IO_REG, c);
-}
-
-char mini_uart_recv (void) {
-    while (1) {
-        if (get32 (AUX_MU_LSR_REG) & 0x01) {
-            break;
-        }
-    }
-    return (get32 (AUX_MU_IO_REG) & 0xFF);
-}
-
-void mini_uart_send_string (char * str) {
-    for (int i = 0; str[i] != '\0'; i++) {
-        mini_uart_send ((char) str[i]);
-    }
-}
-
-void mini_uart_init (void) {
-    static volatile bool init_progress = false;
-    static volatile bool init_done     = false;
-
-    if (init_progress) {
-        while (!init_done)
-            ;
-        return;
-    }
-    init_progress = true;
-
-    unsigned int selector;
-    int          target = BAUD_RATE_REG (115200);
-
-    selector = get32 (GPFSEL1);
-    selector &= ~(7 << 12);
-    selector |= 2 << 12;
-    selector &= ~(7 << 15);
-    selector |= 2 << 15;
-    put32 (GPFSEL1, selector);
-
-    put32 (GPPUD, 0);
-    delay (150);
-    put32 (GPPUDCLK0, (1 << 14) | (1 << 15));
-    delay (150);
-    put32 (GPPUDCLK0, 0);
-
-    put32 (AUX_ENABLES, 1);
-    put32 (AUX_MU_CNTL_REG, 0);
-    put32 (AUX_MU_IER_REG, ENABLE_MU_REC_INT);
-    put32 (AUX_MU_LCR_REG, 3);
-    put32 (AUX_MU_MCR_REG, 0);
-    put32 (AUX_MU_BAUD_REG, target);
-
-    put32 (AUX_MU_CNTL_REG, 3);
-
-    mini_uart_send_string ("\033[2J\033[H");
-    mini_uart_send_string ("Initialised mini UART\r\n");
-
-    init_done = true;
-}
-
-void handle_mini_uart_irq (void) {
-    char c_event = mini_uart_recv ();
-    switch (c_event) {
-        case 17:// device control 1
-            mini_uart_send_string ("Power off");
-            poweroff (40, true);// power off instantly, never return control here
-        case 18:                // device control 2
-            mini_uart_send_string ("Reboot");
-            reboot (40, true);// reboot instantly, never return control here
-        case 19:
-            toggle_blank_screen ();
-        default:
-            mini_uart_send (c_event);
-    }
-}
-
-void mini_putc (void * p, char c) {
-    mini_uart_send (c);
-}
\ No newline at end of file
diff --git a/bulb/src/kernel/mm.S b/bulb/src/kernel/mm.S
deleted file mode 100644
index 92e5692..0000000
--- a/bulb/src/kernel/mm.S
+++ /dev/null
@@ -1,14 +0,0 @@
-.globl memcpy
-memcpy:
-	ldr x3, [x1], #8
-	str x3, [x0], #8
-	subs x2, x2, #8
-	b.gt memcpy
-	ret
-
-.globl memzero
-memzero:
-	str xzr, [x0], #8
-	subs x1, x1, #8
-	b.gt memzero
-	ret
diff --git a/bulb/src/kernel/mm.c b/bulb/src/kernel/mm.c
deleted file mode 100644
index f4da23c..0000000
--- a/bulb/src/kernel/mm.c
+++ /dev/null
@@ -1,19 +0,0 @@
-#include "kernel/mm.h"
-
-static unsigned short mem_map[PAGING_PAGES] = {
-        0,
-};
-
-ptr_t get_free_page () {
-    for (int i = 0; i < PAGING_PAGES; i++) {
-        if (mem_map[i] == 0) {
-            mem_map[i] = 1;
-            return LOW_MEMORY + i * PAGE_SIZE;
-        }
-    }
-    return 0;
-}
-
-void free_page (ptr_t p) {
-    mem_map[(p - LOW_MEMORY) / PAGE_SIZE] = 0;
-}
diff --git a/bulb/src/kernel/mmu.c b/bulb/src/kernel/mmu.c
deleted file mode 100644
index 1e11103..0000000
--- a/bulb/src/kernel/mmu.c
+++ /dev/null
@@ -1,175 +0,0 @@
-#include "kernel/mmu.h"
-
-static volatile unsigned int buffer[] = {32, 0, 0x00038041, 8, 0, 42, 1, 0};
-
-void init_pages () {
-    unsigned long data_page = (unsigned long) &_data / PAGESIZE;
-    unsigned long r, b, *paging = (unsigned long *) &_end;
-
-    unsigned long * PUD0 = paging + 0 * 512;
-    unsigned long * PMD0 = paging + 2 * 512;
-    unsigned long * PTE0 = paging + 1 * 512;
-
-    /* create MMU translation tables at _end */
-    // TTBR0, identity L1
-    b = PBASE >> 21;
-    for (int i = 0; i < RAM_IN_GB; i++) {
-        PUD0[i] = (unsigned long) ((unsigned char *) &_end + (2 + i) * PAGESIZE) |// physical address
-                  PT_PAGE |                                                       // it has the "Present" flag, which must be set, and we have area in it mapped by pages
-                  PT_AF |                                                         // accessed flag. Without this we're going to have a Data Abort exception
-                  PT_USER |                                                       // non-privileged
-                  PT_ISH |                                                        // inner shareable
-                  PT_MEM;                                                         // normal memory
-
-        unsigned int offset = i * 512;
-        // identity L2 2M blocks
-        for (r = 0; r < 512; r++)
-            PMD0[i * 512 + r] = (unsigned long) ((offset + r) << 21) |                // physical address
-                                PT_BLOCK |                                            // map 2M block
-                                PT_AF |                                               // accessed flag
-                                PT_USER |                                             // non-privileged
-                                (offset + r >= b ? PT_OSH | PT_DEV : PT_ISH | PT_MEM);// different attributes for device memory
-    }
-
-    // identity L2, first 2M block
-    PMD0[0] = (unsigned long) ((unsigned char *) &_end + PAGESIZE) |// physical address
-              PT_PAGE |                                             // we have area in it mapped by pages
-              PT_AF |                                               // accessed flag
-              PT_USER |                                             // non-privileged
-              PT_ISH |                                              // inner shareable
-              PT_MEM;                                               // normal memory
-
-    // identity L3
-    for (r = 0; r < 512; r++)
-        PTE0[r] = (unsigned long) (r * PAGESIZE) |               // physical address
-                  PT_PAGE |                                      // map 4k
-                  PT_AF |                                        // accessed flag
-                  PT_USER |                                      // non-privileged
-                  PT_ISH |                                       // inner shareable
-                  ((r < 0x80 || r >= data_page) ? PT_RW : PT_RO);// different for code and data
-}
-
-void init_mmu () {
-    unsigned long data_page = (unsigned long) &_data / PAGESIZE;
-    unsigned long r, b, *paging = (unsigned long *) &_end;
-
-    init_pages ();
-
-    /* okay, now we have to set system registers to enable MMU */
-    // check for 4k granule and at least 36 bits physical address bus */
-    asm volatile("mrs %0, id_aa64mmfr0_el1"
-                 : "=r"(r));
-    b = r & 0xF;
-    if (r & (0xF << 28) /*4k*/ || b < 1 /*36 bits*/) {
-        ERROR ("ERROR: 4k granule or 36 bit address space not supported\n");
-        return;
-    }
-    LOG ("4k granule and 36bit address bus ensured");
-
-    // first, set Memory Attributes array, indexed by PT_MEM, PT_DEV, PT_NC in our example
-    r = (0xFF << 0) |// AttrIdx=0: normal, IWBWA, OWBWA, NTR
-        (0x04 << 8) |// AttrIdx=1: device, nGnRE (must be OSH too)
-        (0x44 << 16);// AttrIdx=2: non cacheable
-    asm volatile("msr mair_el1, %0"
-                 :
-                 : "r"(r));
-    LOG ("MAIR attributes written");
-
-    // next, specify mapping characteristics in translate control register
-    r = (0b00LL << 37) |// TBI=0, no tagging
-        (b << 32) |     // IPS=autodetected
-        (0b10LL << 30) |// TG1=4k
-        (0b11LL << 28) |// SH1=3 inner
-        (0b01LL << 26) |// ORGN1=1 write back
-        (0b01LL << 24) |// IRGN1=1 write back
-        (0b0LL << 23) | // EPD1 enable higher half
-        (25LL << 16) |  // T1SZ=25, 3 levels (512G)
-        (0b00LL << 14) |// TG0=4k
-        (0b11LL << 12) |// SH0=3 inner
-        (0b01LL << 10) |// ORGN0=1 write back
-        (0b01LL << 8) | // IRGN0=1 write back
-        (0b0LL << 7) |  // EPD0 enable lower half
-        (25LL << 0);    // T0SZ=25, 3 levels (512G)
-    asm volatile("msr tcr_el1, %0; isb"
-                 :
-                 : "r"(r));
-    LOG ("Translation control register written");
-
-    // tell the MMU where our translation tables are. TTBR_CNP bit not documented, but required
-    // lower half, user space
-    asm volatile("msr ttbr0_el1, %0"
-                 :
-                 : "r"((unsigned long) &_end + TTBR_CNP));
-    LOG ("TTBR0 written");
-
-    // upper half, kernel space
-    asm volatile("msr ttbr1_el1, %0"
-                 :
-                 : "r"((unsigned long) &_end + TTBR_CNP));
-    LOG ("TTBR1 written");
-
-    // finally, toggle some bits in system control register to enable page translation
-    asm volatile("dsb ish; isb; mrs %0, sctlr_el1"
-                 : "=r"(r));
-    r |= 0xC00800;    // set mandatory reserved bits
-    r &= ~((1 << 25) |// clear EE, little endian translation tables
-           (1 << 24) |// clear E0E
-           (1 << 19) |// clear WXN
-           (1 << 12) |// clear I, no instruction cache
-           (1 << 4) | // clear SA0
-           (1 << 3) | // clear SA
-           (1 << 2) | // clear C, no cache at all
-           (1 << 1)); // clear A, no aligment check
-    r |= (1 << 0);    // set M, enable MMU
-
-    LOG ("Read out system control register");
-
-    asm volatile("msr sctlr_el1, %0; isb"
-                 :
-                 : "r"(r));
-
-    LOG ("Set SCTLR flags and enable MMU");
-
-    *((unsigned int volatile *) (0xFE00B8A0)) = (unsigned long) buffer | 8;
-    LOG ("LED SWITCHING DONE");
-
-    printf ("Msg : %p\r\n", (unsigned long) buffer | 8);
-    printf ("%u ", buffer[0]);
-    printf ("%u ", buffer[1]);
-    printf ("%p ", buffer[2]);
-    printf ("%u ", buffer[3]);
-    printf ("%u ", buffer[4]);
-    printf ("%u ", buffer[5]);
-    printf ("%u ", buffer[6]);
-    printf ("%u \r\n", buffer[7]);
-
-    set_led (POWER_LED, 1);
-}
-
-void data_abort_el1 (ptr_t far, ptr_t esr) {
-    byte_t type  = (esr >> 2) & 0b11;
-    byte_t level = esr & 0b11;
-    esr &= 0b111111;
-
-    printf ("EL 1 - ");
-    printf ("FAR_EL1: %p - ", far);
-    printf ("ESR_EL1: %b\n\r", esr);
-
-    switch (type) {
-        case 0b00:// Address size fault
-            printf ("Address size fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
-            //            exit_process ();
-            break;
-        case 0b01:// Translation fault
-            printf ("Translation fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
-            break;
-        case 0b10:// Access flag fault
-            printf ("Access flag fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
-            //            exit_process ();
-            break;
-        case 0b11:// Permission fault
-            printf ("Segmentation fault during level %ld of table walk on lookup of address %p.\r\n", level, far);
-            //            exit_process ();
-            break;
-    }
-}
\ No newline at end of file
diff --git a/bulb/src/kernel/power.c b/bulb/src/kernel/power.c
deleted file mode 100644
index bcfbc55..0000000
--- a/bulb/src/kernel/power.c
+++ /dev/null
@@ -1,19 +0,0 @@
-#include "kernel/power.h"
-
-void poweroff (unsigned int timeout, bool block) {
-}
-
-void reboot (unsigned int timeout, bool block) {
-    unsigned int pm_rstc, pm_wdog;
-
-    /* Setup watchdog for reset */
-    pm_rstc = get32 (PM_RSTC);
-    // watchdog timer = timer clock / 16; need password (31:16) + value (11:0)
-    pm_wdog = PM_PASSWORD | (timeout & PM_WDOG_TIME_SET);
-    pm_rstc = PM_PASSWORD | (pm_rstc & PM_RSTC_WRCFG_CLR) | PM_RSTC_WRCFG_FULL_RESET;
-    put32 (PM_WDOG, pm_wdog);
-    put32 (PM_RSTC, pm_rstc);
-
-    while (block)
-        ;
-}
diff --git a/bulb/src/kernel/timer.c b/bulb/src/kernel/timer.c
deleted file mode 100644
index 0b3a5f6..0000000
--- a/bulb/src/kernel/timer.c
+++ /dev/null
@@ -1,23 +0,0 @@
-#include "kernel/peripherals/timer.h"
-#include "common/printf.h"
-#include "common/status_led.h"
-#include "common/utils.h"
-//#include "kernel/sched.h"
-
-const unsigned int interval = 200000;
-unsigned int       curVal   = 0;
-
-void timer_init (void) {
-    curVal = get32 (TIMER_CLO);
-    curVal += interval;
-    put32 (TIMER_C1, curVal);
-}
-
-void handle_timer_irq (void) {
-    toggle_led (STATUS_LED);
-
-    curVal += interval;
-    put32 (TIMER_C1, curVal);
-    put32 (TIMER_CS, TIMER_CS_M1);
-    //    timer_tick ();
-}
diff --git a/bulb/src/linker.ld b/bulb/src/linker.ld
deleted file mode 100644
index 332bfc8..0000000
--- a/bulb/src/linker.ld
+++ /dev/null
@@ -1,19 +0,0 @@
-SECTIONS
-{
-    . = 0x80000;
-	.text.boot : { *(.text.boot) }
-	.text : { *(.text) }
-	.rodata : { *(.rodata) }
-    PROVIDE(_data = .);
-	.data : { *(.data) }
-	.bss (NOLOAD) : {
-        . = ALIGN(16);
-        __bss_start = .;
-        *(.bss .bss.*)
-        *(COMMON)
-        __bss_end = .;
-    }
-    . = ALIGN(4096);
-    _end = .;
-}
-__bss_size = (__bss_end - __bss_start) >> 3;
\ No newline at end of file
diff --git a/thorn/include/common/utils.h b/thorn/include/common/utils.h
index 29b53a1..ae4222e 100644
--- a/thorn/include/common/utils.h
+++ b/thorn/include/common/utils.h
@@ -9,4 +9,8 @@ extern unsigned int get32 (unsigned long);
 
 extern int get_el (void);
 
+extern void set_pgd(unsigned long pgd);
+
+extern unsigned long get_pgd();
+
 #endif /*_ROSE_C_BOOT_H */
diff --git a/thorn/include/kernel/sched.h b/thorn/include/kernel/sched.h
index b2b1734..ab1c24d 100644
--- a/thorn/include/kernel/sched.h
+++ b/thorn/include/kernel/sched.h
@@ -39,14 +39,29 @@ struct cpu_context {
     unsigned long pc;
 };
 
+#define MAX_PROCESS_PAGES 16
+
+struct user_page {
+    unsigned long phys_addr;
+    unsigned long virt_addr;
+};
+
+struct mm_struct {
+    unsigned long    pgd;
+    int              user_pages_count;
+    struct user_page user_pages[MAX_PROCESS_PAGES];
+    int              kernel_pages_count;
+    unsigned long    kernel_pages[MAX_PROCESS_PAGES];
+};
+
 struct task_struct {
     struct cpu_context cpu_context;
     long               state;
     long               counter;
     long               priority;
     long               preempt_count;
-    ptr_t              stack;
-    ptr_t              flags;
+    unsigned long      flags;
+    struct mm_struct   mm;
 };
 
 extern void sched_init (void);
@@ -65,6 +80,8 @@ extern void cpu_switch_to (struct task_struct * prev, struct task_struct * next)
 
 extern void exit_process (void);
 
+extern void kill_process (void);
+
 extern void task_init (void);
 
 #define INIT_TASK                                \
diff --git a/thorn/src/common/utils.S b/thorn/src/common/utils.S
index 44be485..1c3c8b6 100644
--- a/thorn/src/common/utils.S
+++ b/thorn/src/common/utils.S
@@ -19,3 +19,20 @@ delay:
 	subs x0, x0, #1
 	bne delay
 	ret
+
+.globl set_pgd
+set_pgd:
+	msr	ttbr0_el1, x0
+	tlbi vmalle1is
+  	DSB ISH              // ensure completion of TLB invalidation
+	isb
+	ret
+
+.globl get_pgd
+get_pgd:
+	mov x1, 0
+	ldr x0, [x1]
+	mov x0, 0x1000
+	msr	ttbr0_el1, x0
+	ldr x0, [x1]
+	ret
diff --git a/thorn/src/kernel/entry.S b/thorn/src/kernel/entry.S
index 950d6ea..9c546c8 100644
--- a/thorn/src/kernel/entry.S
+++ b/thorn/src/kernel/entry.S
@@ -159,8 +159,6 @@ el0_sync:
 	kernel_entry 0
 	mrs	x25, esr_el1													// read the syndrome register
 	lsr	x24, x25, #ESR_ELx_EC_SHIFT						// exception class
-	cmp	x24, #ESR_ELx_EC_SVC64								// SVC in 64-bit state
-	b.eq	el0_svc
 	cmp x24, #ESR_ELx_EC_DABT_LOW
 	b.eq 	el0_da
 	handle_invalid_entry 0, SYNC_ERROR
@@ -192,8 +190,9 @@ el0_da:
 	mrs x0, far_el1
 	mrs x1, esr_el1
 	bl data_abort_el0
-    bl disable_irq
-    eret
+	bl disable_irq
+	bl kill_process
+	eret
 
 .globl ret_from_fork
 ret_from_fork:
diff --git a/thorn/src/kernel/fork.c b/thorn/src/kernel/fork.c
index 799f931..dab1a81 100644
--- a/thorn/src/kernel/fork.c
+++ b/thorn/src/kernel/fork.c
@@ -14,6 +14,11 @@ int copy_process (ptr_t clone_flags, ptr_t fn, ptr_t arg, ptr_t stack) {
         return -1;
     }
 
+    p->mm.pgd = get_free_page();
+    if (!p->mm.pgd) {
+        return -1;
+    }
+
     struct pt_regs * childregs = task_pt_regs (p);
     memzero ((ptr_t) childregs, sizeof (struct pt_regs));
     memzero ((ptr_t) &p->cpu_context, sizeof (struct cpu_context));
@@ -26,7 +31,6 @@ int copy_process (ptr_t clone_flags, ptr_t fn, ptr_t arg, ptr_t stack) {
         *childregs                = *cur_regs;
         childregs->regs[0]        = 0;
         childregs->sp             = stack + PAGE_SIZE;
-        p->stack                  = stack;
     }
     p->flags         = clone_flags;
     p->priority      = current->priority;
@@ -48,12 +52,6 @@ int move_to_user_mode (ptr_t pc) {
     memzero ((ptr_t) regs, sizeof (*regs));
     regs->pc     = pc;
     regs->pstate = PSR_MODE_EL0t;
-    ptr_t stack  = get_free_page ();//allocate new user stack
-    if (!stack) {
-        return -1;
-    }
-    regs->sp       = stack + PAGE_SIZE;
-    current->stack = stack;
     return 0;
 }
 
diff --git a/thorn/src/kernel/irq.c b/thorn/src/kernel/irq.c
index b893bda..f4fc207 100644
--- a/thorn/src/kernel/irq.c
+++ b/thorn/src/kernel/irq.c
@@ -1,7 +1,7 @@
 #include "kernel/irq.h"
 
 const char * entry_error_messages[] = {
-        "SYNC_INVALID_EL1t", "IRQ_INVALID_EL1t", "FIQ_INVALID_EL1t", "ERROR_INVALID_EL1T", "SYNC_INVALID_EL1h", "IRQ_INVALID_EL1h", "FIQ_INVALID_EL1h", "ERROR_INVALID_EL1h", "SYNC_INVALID_EL0_64", "IRQ_INVALID_EL0_64", "FIQ_INVALID_EL0_64", "ERROR_INVALID_EL0_64", "SYNC_INVALID_EL0_32", "IRQ_INVALID_EL0_32", "FIQ_INVALID_EL0_32", "ERROR_INVALID_EL0_32"};
+        "SYNC_INVALID_EL1t", "IRQ_INVALID_EL1t", "FIQ_INVALID_EL1t", "ERROR_INVALID_EL1T", "SYNC_INVALID_EL1h", "IRQ_INVALID_EL1h", "FIQ_INVALID_EL1h", "ERROR_INVALID_EL1h", "SYNC_INVALID_EL0_64", "IRQ_INVALID_EL0_64", "FIQ_INVALID_EL0_64", "ERROR_INVALID_EL0_64", "SYNC_INVALID_EL0_32", "IRQ_INVALID_EL0_32", "FIQ_INVALID_EL0_32", "ERROR_INVALID_EL0_32", "SYNC_ERROR", "SYSCALL_ERROR"};
 
 void enable_interrupt (unsigned int irq) {
     printf ("Interrupt pointer %p\r\n", irq);
diff --git a/thorn/src/kernel/kernel.c b/thorn/src/kernel/kernel.c
index 832b18a..59b6669 100644
--- a/thorn/src/kernel/kernel.c
+++ b/thorn/src/kernel/kernel.c
@@ -18,7 +18,7 @@
 
 void multiplex_print (void * p, char c) {
     printc (c);
-    uart_send (c);
+    // uart_send (c);
 }
 
 void user_process1 (char * array) {
diff --git a/thorn/src/kernel/sched.c b/thorn/src/kernel/sched.c
index ff408dc..3cc9c1c 100644
--- a/thorn/src/kernel/sched.c
+++ b/thorn/src/kernel/sched.c
@@ -61,6 +61,7 @@ void switch_to (struct task_struct * next, int index) {
     }
     struct task_struct * prev = current;
     current                   = next;
+    set_pgd (next->mm.pgd);
     cpu_switch_to (prev, next);
 }
 
@@ -87,13 +88,20 @@ void exit_process () {
             break;
         }
     }
-    if (current->stack) {
-        free_page (current->stack);
-    }
     preempt_enable ();
     schedule ();
 }
 
+void kill_process () {
+    preempt_disable ();
+    for (int i = 0; i < NR_TASKS; i++) {
+        if (task[i] == current) {
+            task[i]->state = TASK_ZOMBIE;
+            break;
+        }
+    }
+    preempt_enable ();
+}
 
 void task_init () {
     memzero ((ptr_t) current, sizeof (struct task_struct));

From 534240db464f31504afbefaeaeea983d6da1ff75 Mon Sep 17 00:00:00 2001
From: Max Streitberger <max.streitberger@gmail.com>
Date: Thu, 4 Nov 2021 15:47:28 +0100
Subject: [PATCH 13/21] feat(mmu): WIP

---
 thorn/include/common/font.h  |  7 +++++++
 thorn/include/common/utils.h |  4 ++--
 thorn/src/common/font.c      | 14 ++++++++++++++
 thorn/src/common/utils.S     | 11 +++++++++--
 thorn/src/kernel/entry.S     |  3 +--
 thorn/src/kernel/fork.c      |  4 +++-
 thorn/src/kernel/kernel.c    |  9 ++++++---
 thorn/src/kernel/mmu.c       |  6 +++---
 thorn/src/kernel/sched.c     | 15 ++++++++++++++-
 9 files changed, 59 insertions(+), 14 deletions(-)

diff --git a/thorn/include/common/font.h b/thorn/include/common/font.h
index b732416..f203cf5 100644
--- a/thorn/include/common/font.h
+++ b/thorn/include/common/font.h
@@ -1,6 +1,8 @@
 #ifndef _ROSE_C_FONT_H
 #define _ROSE_C_FONT_H
 
+#ifndef __ASSEMBLER__
+
 #define FONT_SIZE       8
 #define FONT_FACTOR     2
 #define FONT_REAL_WIDTH (FONT_SIZE * FONT_FACTOR)
@@ -32,6 +34,7 @@ static volatile color_t font_fg;
 const unsigned long long int * font (int c);
 
 void printc (char c);
+void prints (char const * str);
 void printc_location (point_t point, char c);
 
 void putc_screen (void * p, char c);
@@ -39,4 +42,8 @@ void putc_screen (void * p, char c);
 void font_set_normal (void);
 void font_set_error (void);
 
+void test_print();
+void exit_print();
+
 #endif
+#endif
\ No newline at end of file
diff --git a/thorn/include/common/utils.h b/thorn/include/common/utils.h
index ae4222e..411746e 100644
--- a/thorn/include/common/utils.h
+++ b/thorn/include/common/utils.h
@@ -9,8 +9,8 @@ extern unsigned int get32 (unsigned long);
 
 extern int get_el (void);
 
-extern void set_pgd(unsigned long pgd);
+extern void set_pgd (unsigned long pgd);
 
-extern unsigned long get_pgd();
+extern unsigned long get_pgd (void);
 
 #endif /*_ROSE_C_BOOT_H */
diff --git a/thorn/src/common/font.c b/thorn/src/common/font.c
index 86addf5..a397708 100644
--- a/thorn/src/common/font.c
+++ b/thorn/src/common/font.c
@@ -191,6 +191,12 @@ void printc (char c) {
     }
 }
 
+void prints(char const * str) {
+    while (*str) {
+        printc(*str++);
+    }
+}
+
 void font_set_normal (void) {
     font_fg = font_normal_fg;
 }
@@ -201,3 +207,11 @@ void font_set_error (void) {
 void putc_screen (void * p, char c) {
     printc (c);
 }
+
+void test_print() {
+    prints("123454321\n\r");
+}
+
+void exit_print() {
+    prints("exit\n\r");
+}
\ No newline at end of file
diff --git a/thorn/src/common/utils.S b/thorn/src/common/utils.S
index 1c3c8b6..4c4b84d 100644
--- a/thorn/src/common/utils.S
+++ b/thorn/src/common/utils.S
@@ -1,3 +1,5 @@
+#include "common/font.h"
+
 .globl get_el
 get_el:
 	mrs x0, CurrentEL
@@ -22,10 +24,15 @@ delay:
 
 .globl set_pgd
 set_pgd:
+	bl test_print
 	msr	ttbr0_el1, x0
-	tlbi vmalle1is
-  	DSB ISH              // ensure completion of TLB invalidation
+	bl test_print
+	//tlbi vmalle1is
+	bl test_print
+	DSB ISH              // ensure completion of TLB invalidation
+	bl test_print
 	isb
+	bl exit_print
 	ret
 
 .globl get_pgd
diff --git a/thorn/src/kernel/entry.S b/thorn/src/kernel/entry.S
index 9c546c8..c5aa77f 100644
--- a/thorn/src/kernel/entry.S
+++ b/thorn/src/kernel/entry.S
@@ -9,7 +9,7 @@
 	mrs	x1, esr_el1
 	mrs	x2, elr_el1
 	bl	show_invalid_entry_message
-	b 	exit_process
+	b	err_hang
 	.endm
 
 	.macro	ventry	label
@@ -191,7 +191,6 @@ el0_da:
 	mrs x1, esr_el1
 	bl data_abort_el0
 	bl disable_irq
-	bl kill_process
 	eret
 
 .globl ret_from_fork
diff --git a/thorn/src/kernel/fork.c b/thorn/src/kernel/fork.c
index dab1a81..1e04502 100644
--- a/thorn/src/kernel/fork.c
+++ b/thorn/src/kernel/fork.c
@@ -4,8 +4,10 @@
 #include "kernel/entry.h"
 #include "kernel/mm.h"
 #include "kernel/sched.h"
+#include "common/font.h"
 
 int copy_process (ptr_t clone_flags, ptr_t fn, ptr_t arg, ptr_t stack) {
+    prints ("copy process.kl\n\r");
     preempt_disable ();
     struct task_struct * p;
 
@@ -14,7 +16,7 @@ int copy_process (ptr_t clone_flags, ptr_t fn, ptr_t arg, ptr_t stack) {
         return -1;
     }
 
-    p->mm.pgd = get_free_page();
+    p->mm.pgd = get_free_page ();
     if (!p->mm.pgd) {
         return -1;
     }
diff --git a/thorn/src/kernel/kernel.c b/thorn/src/kernel/kernel.c
index 59b6669..310fe11 100644
--- a/thorn/src/kernel/kernel.c
+++ b/thorn/src/kernel/kernel.c
@@ -17,8 +17,8 @@
 #include "kernel/timer.h"
 
 void multiplex_print (void * p, char c) {
-    printc (c);
-    // uart_send (c);
+    // printc (c);
+    uart_send (c);
 }
 
 void user_process1 (char * array) {
@@ -33,6 +33,7 @@ void user_process1 (char * array) {
 }
 
 void user_process () {
+    prints ("User process started.\n\r");
     char buf[30] = {0};
     tfp_sprintf (buf, "User process started\n\r");
     call_sys_write (buf);
@@ -60,7 +61,9 @@ void user_process () {
 }
 
 void kernel_process () {
-    // printf ("Kernel process started. EL %d\r\n", get_el ());
+    prints ("Kernel process started.\n\r");
+    printc ('0' + get_el ());
+    prints ("\n\r");
     int err = move_to_user_mode ((unsigned long) &user_process);
     if (err < 0) {
         printf ("Error while moving process to user mode\n\r");
diff --git a/thorn/src/kernel/mmu.c b/thorn/src/kernel/mmu.c
index 49ab379..e30320c 100644
--- a/thorn/src/kernel/mmu.c
+++ b/thorn/src/kernel/mmu.c
@@ -134,9 +134,9 @@ void data_abort_el0 (ptr_t far, ptr_t esr) {
     byte_t level = esr & 0b11;
     esr &= 0b111111;
 
-    printf ("EL 0 - ");
-    printf ("FAR_EL1: %p - ", far);
-    printf ("ESR_EL1: %b\n\r", esr);
+    // printf ("EL 0 - ");
+    // printf ("FAR_EL1: %p - ", far);
+    // printf ("ESR_EL1: %b\n\r", esr);
 
     switch (type) {
         case 0b00:// Address size fault
diff --git a/thorn/src/kernel/sched.c b/thorn/src/kernel/sched.c
index 3cc9c1c..c5d6fec 100644
--- a/thorn/src/kernel/sched.c
+++ b/thorn/src/kernel/sched.c
@@ -4,6 +4,7 @@
 #include "kernel/fork.h"
 #include "kernel/irq.h"
 #include "kernel/mm.h"
+#include "common/debug.h"
 
 static struct task_struct init_task      = INIT_TASK;
 struct task_struct *      current        = &(init_task);
@@ -45,6 +46,7 @@ void _schedule (void) {
             }
         }
     }
+    CHECKPOINT
     switch_to (task[next], next);
     preempt_enable ();
 }
@@ -61,7 +63,18 @@ void switch_to (struct task_struct * next, int index) {
     }
     struct task_struct * prev = current;
     current                   = next;
-    set_pgd (next->mm.pgd);
+    // set_pgd (next->mm.pgd);
+    CHECKPOINT
+    // asm("tlbi vmalle1is");
+    // CHECKPOINT
+    asm volatile("msr ttbr0_el1, %0"
+                 :
+                 : "r"(next->mm.pgd));
+    CHECKPOINT
+    asm("DSB ISH");
+    CHECKPOINT
+    asm("isb");
+    CHECKPOINT
     cpu_switch_to (prev, next);
 }
 

From 9b346946ed5bb49fb47e72ebbaba075adad289aa Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Wed, 3 Nov 2021 16:37:49 +0100
Subject: [PATCH 14/21] feat(mmu): make all of non-kernel memory non-executable

---
 thorn/src/kernel/mmu.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/thorn/src/kernel/mmu.c b/thorn/src/kernel/mmu.c
index e30320c..821db63 100644
--- a/thorn/src/kernel/mmu.c
+++ b/thorn/src/kernel/mmu.c
@@ -36,17 +36,18 @@ void init_pages () {
               PT_PAGE |                                             // we have area in it mapped by pages
               PT_AF |                                               // accessed flag
               PT_USER |                                             // non-privileged
+              PT_NX |                                               // non-executable
               PT_ISH |                                              // inner shareable
               PT_MEM;                                               // normal memory
 
     // identity L3
     for (r = 0; r < 512; r++)
-        PTE0[r] = (unsigned long) (r * PAGESIZE) |               // physical address
-                  PT_PAGE |                                      // map 4k
-                  PT_AF |                                        // accessed flag
-                  PT_USER |                                      // non-privileged
-                  PT_ISH |                                       // inner shareable
-                  ((r < 0x80 || r >= data_page) ? PT_RW : PT_RO);// different for code and data
+        PTE0[r] = (unsigned long) (r * PAGESIZE) |                       // physical address
+                  PT_PAGE |                                              // map 4k
+                  PT_AF |                                                // accessed flag
+                  PT_USER |                                              // non-privileged
+                  PT_ISH |                                               // inner shareable
+                  ((r < 0x80 || r >= data_page) ? PT_RW | PT_NX : PT_RO);// different for code and data
 }
 
 void init_mmu () {

From 2c7ec97d110eac30d936f7952caf48b5cab0e25e Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Wed, 10 Nov 2021 16:17:31 +0100
Subject: [PATCH 15/21] refactor(mmu): misc changes for debugging; give ELR to
 data abort

---
 Makefile                    | 15 +--------------
 thorn/include/common/font.h |  4 ++--
 thorn/include/kernel/mmu.h  |  3 ++-
 thorn/src/common/font.c     | 14 +++++++-------
 thorn/src/common/utils.S    |  8 ++------
 thorn/src/kernel/entry.S    |  7 +++++--
 thorn/src/kernel/fork.c     |  3 +--
 thorn/src/kernel/kernel.c   |  8 ++++----
 thorn/src/kernel/mmu.c      | 14 ++++++++++----
 thorn/src/kernel/sched.c    | 25 +++----------------------
 10 files changed, 37 insertions(+), 64 deletions(-)

diff --git a/Makefile b/Makefile
index e16cc6d..ab261a7 100644
--- a/Makefile
+++ b/Makefile
@@ -22,7 +22,7 @@ SERIAL_PORT_Darwin     = /dev/$(shell ls /dev | grep usbserial | head -n 2 | tai
 SERIAL_PORT_ALT_Darwin = /dev/$(shell ls /dev | grep usbserial | head -n 1)
 
 # Building
-BUILD_DEFAULT_TARGET = bulb
+BUILD_DEFAULT_TARGET = thorn
 
 # Ensure make still works if someone creates a file named like follows:
 .PHONY: all build clean flash resend send reboot poweroff
@@ -35,7 +35,6 @@ clean:
 	rm -rf $(BUILD) *.img
 	$(MAKE) -C chainloader clean
 	$(MAKE) -C thorn clean
-	$(MAKE) -C bulb clean
 
 # Build the different OSes
 build: build-$(BUILD_DEFAULT_TARGET)
@@ -48,9 +47,6 @@ build-chainloader:
 build-thorn:
 	$(MAKE) -C thorn build
 
-build-bulb:
-	$(MAKE) -C bulb build
-
 # Mount boot partition of SD card onto set mount point to copy image onto it
 flash: flash-$(FLASH_DEFAULT_TARGET)
 
@@ -60,9 +56,6 @@ flash-chainloader:
 flash-thorn:
 	$(MAKE) -C thorn flash
 
-flash-bulb:
-	$(MAKE) -C bulb flash
-
 # Send kernel size + kernel
 setup-serial-Linux:
 	stty -F $(SERIAL_PORT) $(BAUD_RATE) raw cs8 -ixoff -cstopb -parenb
@@ -84,9 +77,6 @@ send-chainloader: setup-serial-$(HOST_OS)
 send-thorn: setup-serial-$(HOST_OS)
 	$(MAKE) -C thorn send
 
-send-bulb: setup-serial-$(HOST_OS)
-	$(MAKE) -C bulb send
-
 # Set up screen on alternate serial port
 screen:
 	screen $(SERIAL_PORT_ALT) $(BAUD_RATE)
@@ -109,6 +99,3 @@ emulate-chainloader:
 emulate-thorn:
 	$(MAKE) -C thorn emulate
 
-emulate-bulb:
-	$(MAKE) -C bulb emulate
-
diff --git a/thorn/include/common/font.h b/thorn/include/common/font.h
index f203cf5..426e898 100644
--- a/thorn/include/common/font.h
+++ b/thorn/include/common/font.h
@@ -42,8 +42,8 @@ void putc_screen (void * p, char c);
 void font_set_normal (void);
 void font_set_error (void);
 
-void test_print();
-void exit_print();
+void test_print ();
+void exit_print ();
 
 #endif
 #endif
\ No newline at end of file
diff --git a/thorn/include/kernel/mmu.h b/thorn/include/kernel/mmu.h
index 169ac60..cda3ed2 100644
--- a/thorn/include/kernel/mmu.h
+++ b/thorn/include/kernel/mmu.h
@@ -11,6 +11,7 @@
 #include "common/status_led.h"
 #include "kernel/mini_uart.h"
 #include "kernel/peripherals/base.h"
+#include "kernel/sched.h"
 
 #define PAGESIZE 4096
 
@@ -45,7 +46,7 @@ static volatile unsigned int __attribute__ ((aligned (16))) buffer[32];
 void init_pages ();
 void init_mmu (void);
 
-void data_abort_el0 (ptr_t far, ptr_t esr);
+void data_abort_el0 (ptr_t far, ptr_t esr, ptr_t elr);
 
 #endif
 #endif//_ROSE_MMU_H
\ No newline at end of file
diff --git a/thorn/src/common/font.c b/thorn/src/common/font.c
index a397708..8f71609 100644
--- a/thorn/src/common/font.c
+++ b/thorn/src/common/font.c
@@ -191,9 +191,9 @@ void printc (char c) {
     }
 }
 
-void prints(char const * str) {
+void prints (char const * str) {
     while (*str) {
-        printc(*str++);
+        printc (*str++);
     }
 }
 
@@ -208,10 +208,10 @@ void putc_screen (void * p, char c) {
     printc (c);
 }
 
-void test_print() {
-    prints("123454321\n\r");
+void test_print () {
+    prints ("test\n\r");
 }
 
-void exit_print() {
-    prints("exit\n\r");
-}
\ No newline at end of file
+void exit_print () {
+    prints ("exit\n\r");
+}
diff --git a/thorn/src/common/utils.S b/thorn/src/common/utils.S
index 4c4b84d..018062d 100644
--- a/thorn/src/common/utils.S
+++ b/thorn/src/common/utils.S
@@ -24,13 +24,9 @@ delay:
 
 .globl set_pgd
 set_pgd:
-	bl test_print
 	msr	ttbr0_el1, x0
-	bl test_print
-	//tlbi vmalle1is
-	bl test_print
-	DSB ISH              // ensure completion of TLB invalidation
-	bl test_print
+//	tlbi vmalle1is
+	dsb ish              // ensure completion of TLB invalidation
 	isb
 	bl exit_print
 	ret
diff --git a/thorn/src/kernel/entry.S b/thorn/src/kernel/entry.S
index c5aa77f..4dd8c16 100644
--- a/thorn/src/kernel/entry.S
+++ b/thorn/src/kernel/entry.S
@@ -157,9 +157,11 @@ el0_irq:
 
 el0_sync:
 	kernel_entry 0
-	mrs	x25, esr_el1													// read the syndrome register
+	mrs	x25, esr_el1									// read the syndrome register
 	lsr	x24, x25, #ESR_ELx_EC_SHIFT						// exception class
-	cmp x24, #ESR_ELx_EC_DABT_LOW
+    cmp	x24, #ESR_ELx_EC_SVC64							// SVC in 64-bit state
+    b.eq	el0_svc
+    cmp x24, #ESR_ELx_EC_DABT_LOW
 	b.eq 	el0_da
 	handle_invalid_entry 0, SYNC_ERROR
 
@@ -189,6 +191,7 @@ el0_da:
 	bl enable_irq
 	mrs x0, far_el1
 	mrs x1, esr_el1
+	mrs	x2, elr_el1
 	bl data_abort_el0
 	bl disable_irq
 	eret
diff --git a/thorn/src/kernel/fork.c b/thorn/src/kernel/fork.c
index 1e04502..49a49b8 100644
--- a/thorn/src/kernel/fork.c
+++ b/thorn/src/kernel/fork.c
@@ -1,13 +1,12 @@
 #include "kernel/fork.h"
+#include "common/font.h"
 #include "common/printf.h"
 #include "common/utils.h"
 #include "kernel/entry.h"
 #include "kernel/mm.h"
 #include "kernel/sched.h"
-#include "common/font.h"
 
 int copy_process (ptr_t clone_flags, ptr_t fn, ptr_t arg, ptr_t stack) {
-    prints ("copy process.kl\n\r");
     preempt_disable ();
     struct task_struct * p;
 
diff --git a/thorn/src/kernel/kernel.c b/thorn/src/kernel/kernel.c
index 310fe11..6698c38 100644
--- a/thorn/src/kernel/kernel.c
+++ b/thorn/src/kernel/kernel.c
@@ -17,8 +17,8 @@
 #include "kernel/timer.h"
 
 void multiplex_print (void * p, char c) {
-    // printc (c);
-    uart_send (c);
+    printc (c);
+    //    uart_send (c);
 }
 
 void user_process1 (char * array) {
@@ -116,8 +116,8 @@ void kernel_main (int processor_id) {
     printf ("Hello, from processor %d in EL %d\n\r", processor_id, get_el ());
     init_mmu ();
 
-    current_processor++;
-    while (current_processor != 4) {}
+    //    current_processor++;
+    //    while (current_processor != 4) {}
 
     switch (processor_id) {
         case 0: {
diff --git a/thorn/src/kernel/mmu.c b/thorn/src/kernel/mmu.c
index 821db63..3cb0a5d 100644
--- a/thorn/src/kernel/mmu.c
+++ b/thorn/src/kernel/mmu.c
@@ -130,14 +130,15 @@ void init_mmu () {
     LOG ("Set SCTLR flags and enable MMU");
 }
 
-void data_abort_el0 (ptr_t far, ptr_t esr) {
+void data_abort_el0 (ptr_t far, ptr_t esr, ptr_t elr) {
     byte_t type  = (esr >> 2) & 0b11;
     byte_t level = esr & 0b11;
     esr &= 0b111111;
 
-    // printf ("EL 0 - ");
-    // printf ("FAR_EL1: %p - ", far);
-    // printf ("ESR_EL1: %b\n\r", esr);
+    printf ("EL 0 - ");
+    printf ("FAR_EL1: %p - ", far);
+    printf ("ELR_EL1: %p - ", elr);
+    printf ("ESR_EL1: %b\r\n", esr);
 
     switch (type) {
         case 0b00:// Address size fault
@@ -146,6 +147,11 @@ void data_abort_el0 (ptr_t far, ptr_t esr) {
             break;
         case 0b01:// Translation fault
             printf ("Translation fault during level %u of table walk on lookup of address %p.\r\n", level, far);
+            set_pgd ((unsigned long) &_end + TTBR_CNP);
+            //            asm volatile("msr ttbr0_el1, %0"
+            //                         :
+            //                         : "r"((unsigned long) &_end + TTBR_CNP));
+            LOG ("Successfully (?) updated TTBR");
             break;
         case 0b10:// Access flag fault
             printf ("Access flag fault during level %u of table walk on lookup of address %p.\r\n", level, far);
diff --git a/thorn/src/kernel/sched.c b/thorn/src/kernel/sched.c
index c5d6fec..f0f07cc 100644
--- a/thorn/src/kernel/sched.c
+++ b/thorn/src/kernel/sched.c
@@ -1,10 +1,10 @@
 #include "kernel/sched.h"
+#include "common/debug.h"
 #include "common/printf.h"
 #include "common/utils.h"
 #include "kernel/fork.h"
 #include "kernel/irq.h"
 #include "kernel/mm.h"
-#include "common/debug.h"
 
 static struct task_struct init_task      = INIT_TASK;
 struct task_struct *      current        = &(init_task);
@@ -21,7 +21,6 @@ void preempt_enable (void) {
     current->preempt_count--;
 }
 
-
 void _schedule (void) {
     preempt_disable ();
     int                  next, c;
@@ -46,7 +45,6 @@ void _schedule (void) {
             }
         }
     }
-    CHECKPOINT
     switch_to (task[next], next);
     preempt_enable ();
 }
@@ -56,25 +54,19 @@ void schedule (void) {
     _schedule ();
 }
 
-
 void switch_to (struct task_struct * next, int index) {
     if (current == next) {
         return;
     }
     struct task_struct * prev = current;
     current                   = next;
-    // set_pgd (next->mm.pgd);
-    CHECKPOINT
-    // asm("tlbi vmalle1is");
-    // CHECKPOINT
+    //    set_pgd (next->mm.pgd);
+    asm("tlbi vmalle1is");
     asm volatile("msr ttbr0_el1, %0"
                  :
                  : "r"(next->mm.pgd));
-    CHECKPOINT
     asm("DSB ISH");
-    CHECKPOINT
     asm("isb");
-    CHECKPOINT
     cpu_switch_to (prev, next);
 }
 
@@ -105,17 +97,6 @@ void exit_process () {
     schedule ();
 }
 
-void kill_process () {
-    preempt_disable ();
-    for (int i = 0; i < NR_TASKS; i++) {
-        if (task[i] == current) {
-            task[i]->state = TASK_ZOMBIE;
-            break;
-        }
-    }
-    preempt_enable ();
-}
-
 void task_init () {
     memzero ((ptr_t) current, sizeof (struct task_struct));
     current->priority = 1;

From b121473c8dec638ff24c10822a6730963f156384 Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Wed, 10 Nov 2021 17:12:04 +0100
Subject: [PATCH 16/21] chore: figure out mmu gets stuck in schedule

---
 thorn/include/common/font.h  |  2 +-
 thorn/include/kernel/mm.h    |  2 +-
 thorn/include/kernel/mmu.h   |  1 +
 thorn/include/kernel/sched.h |  1 +
 thorn/src/kernel/boot.S      | 19 ++++++++++---------
 thorn/src/kernel/entry.S     |  5 +++--
 thorn/src/kernel/irq.c       |  2 +-
 thorn/src/kernel/kernel.c    | 11 ++++++-----
 thorn/src/kernel/mmu.c       | 14 +++++++-------
 thorn/src/kernel/sched.c     | 12 ++++++------
 thorn/src/kernel/timer.c     |  1 +
 11 files changed, 38 insertions(+), 32 deletions(-)

diff --git a/thorn/include/common/font.h b/thorn/include/common/font.h
index 426e898..4cd6fdd 100644
--- a/thorn/include/common/font.h
+++ b/thorn/include/common/font.h
@@ -4,7 +4,7 @@
 #ifndef __ASSEMBLER__
 
 #define FONT_SIZE       8
-#define FONT_FACTOR     2
+#define FONT_FACTOR     3
 #define FONT_REAL_WIDTH (FONT_SIZE * FONT_FACTOR)
 
 // Spacing between lines in pixels
diff --git a/thorn/include/kernel/mm.h b/thorn/include/kernel/mm.h
index d2f325a..642bc3e 100644
--- a/thorn/include/kernel/mm.h
+++ b/thorn/include/kernel/mm.h
@@ -11,7 +11,7 @@
 #define PAGE_SIZE    (1 << PAGE_SHIFT)
 #define SECTION_SIZE (1 << SECTION_SHIFT)
 
-#define LOW_MEMORY  (2 * SECTION_SIZE)
+#define LOW_MEMORY  (1 * SECTION_SIZE)
 #define HIGH_MEMORY 0x70000000
 
 #define PAGING_MEMORY (HIGH_MEMORY - LOW_MEMORY)
diff --git a/thorn/include/kernel/mmu.h b/thorn/include/kernel/mmu.h
index cda3ed2..07c5c6e 100644
--- a/thorn/include/kernel/mmu.h
+++ b/thorn/include/kernel/mmu.h
@@ -9,6 +9,7 @@
 #include "common/font.h"
 #include "common/logging.h"
 #include "common/status_led.h"
+#include "kernel/irq.h"
 #include "kernel/mini_uart.h"
 #include "kernel/peripherals/base.h"
 #include "kernel/sched.h"
diff --git a/thorn/include/kernel/sched.h b/thorn/include/kernel/sched.h
index ab1c24d..a01b136 100644
--- a/thorn/include/kernel/sched.h
+++ b/thorn/include/kernel/sched.h
@@ -1,6 +1,7 @@
 #ifndef _ROSE_K_SCHED_H
 #define _ROSE_K_SCHED_H
 
+#include "common/font.h"
 #include "common/stddef.h"
 
 #define THREAD_CPU_CONTEXT 0// offset of cpu_context in task_struct
diff --git a/thorn/src/kernel/boot.S b/thorn/src/kernel/boot.S
index b83930e..50f40d2 100644
--- a/thorn/src/kernel/boot.S
+++ b/thorn/src/kernel/boot.S
@@ -21,16 +21,17 @@ init_bss:
     bl	memzero
 
     adr x0, move_to_el1
-    mov	x1, #0xe0
-    str	x0, [x1]
 
-    mov	x1, #0xe8
-    str	x0, [x1]
-
-    mov	x1, #0xf0
-    str	x0, [x1]
-
-    sev
+//    mov	x1, #0xe0
+//    str	x0, [x1]
+//
+//    mov	x1, #0xe8
+//    str	x0, [x1]
+//
+//    mov	x1, #0xf0
+//    str	x0, [x1]
+//
+//    sev
 
     b move_to_el1
 
diff --git a/thorn/src/kernel/entry.S b/thorn/src/kernel/entry.S
index 4dd8c16..b7bafbe 100644
--- a/thorn/src/kernel/entry.S
+++ b/thorn/src/kernel/entry.S
@@ -188,12 +188,13 @@ ret_from_syscall:
 	kernel_exit 0
 
 el0_da:
-	bl enable_irq
+    bl preempt_disable
 	mrs x0, far_el1
 	mrs x1, esr_el1
 	mrs	x2, elr_el1
 	bl data_abort_el0
-	bl disable_irq
+    bl preempt_enable
+    bl disable_irq
 	eret
 
 .globl ret_from_fork
diff --git a/thorn/src/kernel/irq.c b/thorn/src/kernel/irq.c
index f4fc207..2c95c0f 100644
--- a/thorn/src/kernel/irq.c
+++ b/thorn/src/kernel/irq.c
@@ -20,7 +20,7 @@ void assign_target (unsigned int irq, unsigned int cpu) {
 }
 
 void show_invalid_entry_message (int type, ptr_t esr, ptr_t address) {
-    printf ("Type %s, ESR: %p, address, %p\r\n", entry_error_messages[type], (void *) esr, (void *) address);
+    printf ("Type %s, ESR: %p, ELR: %p\r\n", entry_error_messages[type], (void *) esr, (void *) address);
 }
 
 void enable_interrupt_controller () {
diff --git a/thorn/src/kernel/kernel.c b/thorn/src/kernel/kernel.c
index 6698c38..a8bf6a1 100644
--- a/thorn/src/kernel/kernel.c
+++ b/thorn/src/kernel/kernel.c
@@ -33,7 +33,7 @@ void user_process1 (char * array) {
 }
 
 void user_process () {
-    prints ("User process started.\n\r");
+    printf ("User process started.\n\r");
     char buf[30] = {0};
     tfp_sprintf (buf, "User process started\n\r");
     call_sys_write (buf);
@@ -73,10 +73,6 @@ void kernel_process () {
 void kernel_init (void) {
     uart_init ();
     init_printf (0, putc);
-    irq_vector_init ();
-    timer_init ();
-    enable_interrupt_controller ();
-    enable_irq ();
     task_init ();
 
     // Turn status led OFF and power led ON
@@ -119,6 +115,11 @@ void kernel_main (int processor_id) {
     //    current_processor++;
     //    while (current_processor != 4) {}
 
+    irq_vector_init ();
+    timer_init ();
+    enable_interrupt_controller ();
+    enable_irq ();
+
     switch (processor_id) {
         case 0: {
             int res = copy_process (PF_KTHREAD, (unsigned long) &kernel_process, 0, 0);
diff --git a/thorn/src/kernel/mmu.c b/thorn/src/kernel/mmu.c
index 3cb0a5d..d4c61f4 100644
--- a/thorn/src/kernel/mmu.c
+++ b/thorn/src/kernel/mmu.c
@@ -135,9 +135,8 @@ void data_abort_el0 (ptr_t far, ptr_t esr, ptr_t elr) {
     byte_t level = esr & 0b11;
     esr &= 0b111111;
 
-    printf ("EL 0 - ");
-    printf ("FAR_EL1: %p - ", far);
     printf ("ELR_EL1: %p - ", elr);
+    printf ("FAR_EL1: %p - ", far);
     printf ("ESR_EL1: %b\r\n", esr);
 
     switch (type) {
@@ -147,11 +146,12 @@ void data_abort_el0 (ptr_t far, ptr_t esr, ptr_t elr) {
             break;
         case 0b01:// Translation fault
             printf ("Translation fault during level %u of table walk on lookup of address %p.\r\n", level, far);
-            set_pgd ((unsigned long) &_end + TTBR_CNP);
-            //            asm volatile("msr ttbr0_el1, %0"
-            //                         :
-            //                         : "r"((unsigned long) &_end + TTBR_CNP));
-            LOG ("Successfully (?) updated TTBR");
+            asm volatile("msr ttbr0_el1, %0"
+                         :
+                         : "r"((unsigned long) &_end + TTBR_CNP));
+            //            asm volatile("dsb ish");
+            //            asm volatile("isb");
+            enable_irq ();
             break;
         case 0b10:// Access flag fault
             printf ("Access flag fault during level %u of table walk on lookup of address %p.\r\n", level, far);
diff --git a/thorn/src/kernel/sched.c b/thorn/src/kernel/sched.c
index f0f07cc..5a8e469 100644
--- a/thorn/src/kernel/sched.c
+++ b/thorn/src/kernel/sched.c
@@ -26,6 +26,7 @@ void _schedule (void) {
     int                  next, c;
     struct task_struct * p;
     while (1) {
+        printc ('-');
         c    = -1;
         next = 0;
         for (int i = 0; i < NR_TASKS; i++) {
@@ -61,12 +62,11 @@ void switch_to (struct task_struct * next, int index) {
     struct task_struct * prev = current;
     current                   = next;
     //    set_pgd (next->mm.pgd);
-    asm("tlbi vmalle1is");
-    asm volatile("msr ttbr0_el1, %0"
-                 :
-                 : "r"(next->mm.pgd));
-    asm("DSB ISH");
-    asm("isb");
+    //    asm volatile("msr ttbr0_el1, %0"
+    //                 :
+    //                 : "r"(next->mm.pgd));
+    //    asm("DSB ISH");
+    //    asm("isb");
     cpu_switch_to (prev, next);
 }
 
diff --git a/thorn/src/kernel/timer.c b/thorn/src/kernel/timer.c
index 0fe4556..79be217 100644
--- a/thorn/src/kernel/timer.c
+++ b/thorn/src/kernel/timer.c
@@ -15,6 +15,7 @@ void timer_init (void) {
 
 void handle_timer_irq (void) {
     toggle_led (STATUS_LED);
+    printc ('|');
 
     curVal += interval;
     put32 (TIMER_C1, curVal);

From dee35633f98f9e5341d23dcfc693a4cbede97bb5 Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Thu, 11 Nov 2021 10:20:01 +0100
Subject: [PATCH 17/21] WIP: figure out why user_process starts with sp = 0

---
 thorn/src/kernel/fork.c   | 2 +-
 thorn/src/kernel/kernel.c | 1 +
 thorn/src/kernel/sched.c  | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/thorn/src/kernel/fork.c b/thorn/src/kernel/fork.c
index 49a49b8..4da01af 100644
--- a/thorn/src/kernel/fork.c
+++ b/thorn/src/kernel/fork.c
@@ -37,7 +37,7 @@ int copy_process (ptr_t clone_flags, ptr_t fn, ptr_t arg, ptr_t stack) {
     p->priority      = current->priority;
     p->state         = TASK_RUNNING;
     p->counter       = p->priority;
-    p->preempt_count = 1;//disable preemtion until schedule_tail
+    p->preempt_count = 1;//disable preemption until schedule_tail
 
     p->cpu_context.pc = (ptr_t) ret_from_fork;
     p->cpu_context.sp = (ptr_t) childregs;
diff --git a/thorn/src/kernel/kernel.c b/thorn/src/kernel/kernel.c
index a8bf6a1..c3f3425 100644
--- a/thorn/src/kernel/kernel.c
+++ b/thorn/src/kernel/kernel.c
@@ -119,6 +119,7 @@ void kernel_main (int processor_id) {
     timer_init ();
     enable_interrupt_controller ();
     enable_irq ();
+    CHECKPOINT
 
     switch (processor_id) {
         case 0: {
diff --git a/thorn/src/kernel/sched.c b/thorn/src/kernel/sched.c
index 5a8e469..3795bd7 100644
--- a/thorn/src/kernel/sched.c
+++ b/thorn/src/kernel/sched.c
@@ -23,7 +23,7 @@ void preempt_enable (void) {
 
 void _schedule (void) {
     preempt_disable ();
-    int                  next, c;
+    long                 next, c;
     struct task_struct * p;
     while (1) {
         printc ('-');

From 83813b77f03f29bfd464f17466457e357ac5ef85 Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Thu, 11 Nov 2021 14:41:06 +0100
Subject: [PATCH 18/21] WIP: try to figure out why user_process hangs
 immediately

---
 thorn/include/kernel/irq.h |  2 +-
 thorn/src/common/utils.S   |  2 +-
 thorn/src/kernel/entry.S   | 22 ++++++++++++----------
 thorn/src/kernel/irq.c     |  4 ++--
 thorn/src/kernel/kernel.c  |  3 +++
 thorn/src/kernel/mmu.c     |  4 ++--
 thorn/src/kernel/sched.c   | 12 ++++++++----
 7 files changed, 29 insertions(+), 20 deletions(-)

diff --git a/thorn/include/kernel/irq.h b/thorn/include/kernel/irq.h
index d95cc0b..47652e8 100644
--- a/thorn/include/kernel/irq.h
+++ b/thorn/include/kernel/irq.h
@@ -13,7 +13,7 @@
 
 void enable_interrupt_controller (void);
 
-void show_invalid_entry_message (int type, ptr_t esr, ptr_t address);
+void show_invalid_entry_message (int type, ptr_t esr, ptr_t elr, ptr_t far);
 
 void irq_vector_init (void);
 
diff --git a/thorn/src/common/utils.S b/thorn/src/common/utils.S
index 018062d..976cc8b 100644
--- a/thorn/src/common/utils.S
+++ b/thorn/src/common/utils.S
@@ -25,7 +25,7 @@ delay:
 .globl set_pgd
 set_pgd:
 	msr	ttbr0_el1, x0
-//	tlbi vmalle1is
+//	tlbi vmalle1is      // Crashes CPU
 	dsb ish              // ensure completion of TLB invalidation
 	isb
 	bl exit_print
diff --git a/thorn/src/kernel/entry.S b/thorn/src/kernel/entry.S
index b7bafbe..07606ed 100644
--- a/thorn/src/kernel/entry.S
+++ b/thorn/src/kernel/entry.S
@@ -8,6 +8,7 @@
 	mov	x0, #\type
 	mrs	x1, esr_el1
 	mrs	x2, elr_el1
+    mrs x3, far_el1
 	bl	show_invalid_entry_message
 	b	err_hang
 	.endm
@@ -92,19 +93,19 @@ vectors:
 	ventry	error_invalid_el1t			// Error EL1t
 
 	ventry	sync_invalid_el1h			// Synchronous EL1h
-	ventry	el1_irq					// IRQ EL1h
+	ventry	el1_irq					    // IRQ EL1h
 	ventry	fiq_invalid_el1h			// FIQ EL1h
 	ventry	error_invalid_el1h			// Error EL1h
 
-	ventry	el0_sync				// Synchronous 64-bit EL0
-	ventry	el0_irq					// IRQ 64-bit EL0
+	ventry	el0_sync				    // Synchronous 64-bit EL0
+	ventry	el0_irq					    // IRQ 64-bit EL0
 	ventry	fiq_invalid_el0_64			// FIQ 64-bit EL0
-	ventry	error_invalid_el0_64			// Error 64-bit EL0
+	ventry	error_invalid_el0_64		// Error 64-bit EL0
 
 	ventry	sync_invalid_el0_32			// Synchronous 32-bit EL0
 	ventry	irq_invalid_el0_32			// IRQ 32-bit EL0
 	ventry	fiq_invalid_el0_32			// FIQ 32-bit EL0
-	ventry	error_invalid_el0_32			// Error 32-bit EL0
+	ventry	error_invalid_el0_32		// Error 32-bit EL0
 
 sync_invalid_el1t:
 	handle_invalid_entry 1,  SYNC_INVALID_EL1t
@@ -156,6 +157,7 @@ el0_irq:
 	kernel_exit 0
 
 el0_sync:
+    bl test_print
 	kernel_entry 0
 	mrs	x25, esr_el1									// read the syndrome register
 	lsr	x24, x25, #ESR_ELx_EC_SHIFT						// exception class
@@ -170,15 +172,15 @@ scno	.req	x26															// syscall number
 stbl	.req	x27															// syscall table pointer
 
 el0_svc:
-	adr	stbl, sys_call_table									// load syscall table pointer
-	uxtw	scno, w8														// syscall number in w8
+	adr	stbl, sys_call_table		// load syscall table pointer
+	uxtw	scno, w8				// syscall number in w8
 	mov	sc_nr, #__NR_syscalls
 	bl	enable_irq
-	cmp     scno, sc_nr                     	// check upper syscall limit
+	cmp     scno, sc_nr             // check upper syscall limit
 	b.hs	ni_sys
 
-	ldr	x16, [stbl, scno, lsl #3]							// address in the syscall table
-	blr	x16																		// call sys_* routine
+	ldr	x16, [stbl, scno, lsl #3]	// address in the syscall table
+	blr	x16							// call sys_* routine
 	b	ret_from_syscall
 ni_sys:
 	handle_invalid_entry 0, SYSCALL_ERROR
diff --git a/thorn/src/kernel/irq.c b/thorn/src/kernel/irq.c
index 2c95c0f..c182b39 100644
--- a/thorn/src/kernel/irq.c
+++ b/thorn/src/kernel/irq.c
@@ -19,8 +19,8 @@ void assign_target (unsigned int irq, unsigned int cpu) {
     put32 (targetRegister, get32 (targetRegister) | (1 << 8));
 }
 
-void show_invalid_entry_message (int type, ptr_t esr, ptr_t address) {
-    printf ("Type %s, ESR: %p, ELR: %p\r\n", entry_error_messages[type], (void *) esr, (void *) address);
+void show_invalid_entry_message (int type, ptr_t esr, ptr_t elr, ptr_t far) {
+    printf ("Type %s, FAR: %p, ESR: %p, ELR: %p\r\n", entry_error_messages[type], (void *) far, (void *) (esr >> ESR_ELx_EC_SHIFT), (void *) elr);
 }
 
 void enable_interrupt_controller () {
diff --git a/thorn/src/kernel/kernel.c b/thorn/src/kernel/kernel.c
index c3f3425..660997b 100644
--- a/thorn/src/kernel/kernel.c
+++ b/thorn/src/kernel/kernel.c
@@ -68,6 +68,9 @@ void kernel_process () {
     if (err < 0) {
         printf ("Error while moving process to user mode\n\r");
     }
+    // Explicitly remove this task..?
+    --nr_tasks;
+    current->state = TASK_ZOMBIE;
 }
 
 void kernel_init (void) {
diff --git a/thorn/src/kernel/mmu.c b/thorn/src/kernel/mmu.c
index d4c61f4..79505ab 100644
--- a/thorn/src/kernel/mmu.c
+++ b/thorn/src/kernel/mmu.c
@@ -149,8 +149,8 @@ void data_abort_el0 (ptr_t far, ptr_t esr, ptr_t elr) {
             asm volatile("msr ttbr0_el1, %0"
                          :
                          : "r"((unsigned long) &_end + TTBR_CNP));
-            //            asm volatile("dsb ish");
-            //            asm volatile("isb");
+            asm volatile("dsb ish");
+            asm volatile("isb");
             enable_irq ();
             break;
         case 0b10:// Access flag fault
diff --git a/thorn/src/kernel/sched.c b/thorn/src/kernel/sched.c
index 3795bd7..6865db4 100644
--- a/thorn/src/kernel/sched.c
+++ b/thorn/src/kernel/sched.c
@@ -23,13 +23,17 @@ void preempt_enable (void) {
 
 void _schedule (void) {
     preempt_disable ();
-    long                 next, c;
+    long                 next, c, cur;
     struct task_struct * p;
     while (1) {
         printc ('-');
+        printc ('0' + nr_tasks);
         c    = -1;
         next = 0;
+        cur;
         for (int i = 0; i < NR_TASKS; i++) {
+            if (task[i] == current)
+                cur = i;
             p = task[i];
             if (p && p->state == TASK_RUNNING && p->counter > c) {
                 c    = p->counter;
@@ -37,6 +41,7 @@ void _schedule (void) {
             }
         }
         if (c) {
+            printc ('0' + cur);
             break;
         }
         for (int i = 0; i < NR_TASKS; i++) {
@@ -61,12 +66,11 @@ void switch_to (struct task_struct * next, int index) {
     }
     struct task_struct * prev = current;
     current                   = next;
-    //    set_pgd (next->mm.pgd);
     //    asm volatile("msr ttbr0_el1, %0"
     //                 :
     //                 : "r"(next->mm.pgd));
-    //    asm("DSB ISH");
-    //    asm("isb");
+    //    asm volatile("DSB ISH");
+    //    asm volatile ("isb");
     cpu_switch_to (prev, next);
 }
 

From c1b826e27f67268e0ce8386eb3c07f1ea4979b8c Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Thu, 11 Nov 2021 15:21:42 +0100
Subject: [PATCH 19/21] refactor(mmu): right now, everything runs fine

User and kernel space both use the same, 1-to-1 mapped page tables
---
 thorn/include/common/font.h | 1 -
 thorn/src/common/font.c     | 6 +-----
 thorn/src/common/utils.S    | 1 -
 thorn/src/kernel/entry.S    | 1 -
 thorn/src/kernel/fork.c     | 6 +++---
 thorn/src/kernel/irq.c      | 2 +-
 thorn/src/kernel/kernel.c   | 8 +-------
 thorn/src/kernel/sched.c    | 3 ---
 thorn/src/kernel/timer.c    | 1 -
 9 files changed, 6 insertions(+), 23 deletions(-)

diff --git a/thorn/include/common/font.h b/thorn/include/common/font.h
index 4cd6fdd..89b011b 100644
--- a/thorn/include/common/font.h
+++ b/thorn/include/common/font.h
@@ -43,7 +43,6 @@ void font_set_normal (void);
 void font_set_error (void);
 
 void test_print ();
-void exit_print ();
 
 #endif
 #endif
\ No newline at end of file
diff --git a/thorn/src/common/font.c b/thorn/src/common/font.c
index 8f71609..a093572 100644
--- a/thorn/src/common/font.c
+++ b/thorn/src/common/font.c
@@ -209,9 +209,5 @@ void putc_screen (void * p, char c) {
 }
 
 void test_print () {
-    prints ("test\n\r");
-}
-
-void exit_print () {
-    prints ("exit\n\r");
+    prints ("test\r\n");
 }
diff --git a/thorn/src/common/utils.S b/thorn/src/common/utils.S
index 976cc8b..d6a9596 100644
--- a/thorn/src/common/utils.S
+++ b/thorn/src/common/utils.S
@@ -28,7 +28,6 @@ set_pgd:
 //	tlbi vmalle1is      // Crashes CPU
 	dsb ish              // ensure completion of TLB invalidation
 	isb
-	bl exit_print
 	ret
 
 .globl get_pgd
diff --git a/thorn/src/kernel/entry.S b/thorn/src/kernel/entry.S
index 07606ed..e37bd6c 100644
--- a/thorn/src/kernel/entry.S
+++ b/thorn/src/kernel/entry.S
@@ -157,7 +157,6 @@ el0_irq:
 	kernel_exit 0
 
 el0_sync:
-    bl test_print
 	kernel_entry 0
 	mrs	x25, esr_el1									// read the syndrome register
 	lsr	x24, x25, #ESR_ELx_EC_SHIFT						// exception class
diff --git a/thorn/src/kernel/fork.c b/thorn/src/kernel/fork.c
index 4da01af..8f95645 100644
--- a/thorn/src/kernel/fork.c
+++ b/thorn/src/kernel/fork.c
@@ -50,9 +50,9 @@ int copy_process (ptr_t clone_flags, ptr_t fn, ptr_t arg, ptr_t stack) {
 
 int move_to_user_mode (ptr_t pc) {
     struct pt_regs * regs = task_pt_regs (current);
-    memzero ((ptr_t) regs, sizeof (*regs));
-    regs->pc     = pc;
-    regs->pstate = PSR_MODE_EL0t;
+    regs->pc              = pc;
+    regs->pstate          = PSR_MODE_EL0t;
+    regs->sp              = 2 * PAGE_SIZE;
     return 0;
 }
 
diff --git a/thorn/src/kernel/irq.c b/thorn/src/kernel/irq.c
index c182b39..98a4239 100644
--- a/thorn/src/kernel/irq.c
+++ b/thorn/src/kernel/irq.c
@@ -20,7 +20,7 @@ void assign_target (unsigned int irq, unsigned int cpu) {
 }
 
 void show_invalid_entry_message (int type, ptr_t esr, ptr_t elr, ptr_t far) {
-    printf ("Type %s, FAR: %p, ESR: %p, ELR: %p\r\n", entry_error_messages[type], (void *) far, (void *) (esr >> ESR_ELx_EC_SHIFT), (void *) elr);
+    printf ("Type %s, FAR: %p, ESR: %p, ELR: %p\r\n", entry_error_messages[type], (void *) far, (void *) (esr >> 0), (void *) elr);
 }
 
 void enable_interrupt_controller () {
diff --git a/thorn/src/kernel/kernel.c b/thorn/src/kernel/kernel.c
index 660997b..cc95c6d 100644
--- a/thorn/src/kernel/kernel.c
+++ b/thorn/src/kernel/kernel.c
@@ -33,7 +33,6 @@ void user_process1 (char * array) {
 }
 
 void user_process () {
-    printf ("User process started.\n\r");
     char buf[30] = {0};
     tfp_sprintf (buf, "User process started\n\r");
     call_sys_write (buf);
@@ -61,16 +60,11 @@ void user_process () {
 }
 
 void kernel_process () {
-    prints ("Kernel process started.\n\r");
-    printc ('0' + get_el ());
-    prints ("\n\r");
+    printf ("Kernel process started.\n\r");
     int err = move_to_user_mode ((unsigned long) &user_process);
     if (err < 0) {
         printf ("Error while moving process to user mode\n\r");
     }
-    // Explicitly remove this task..?
-    --nr_tasks;
-    current->state = TASK_ZOMBIE;
 }
 
 void kernel_init (void) {
diff --git a/thorn/src/kernel/sched.c b/thorn/src/kernel/sched.c
index 6865db4..79fb818 100644
--- a/thorn/src/kernel/sched.c
+++ b/thorn/src/kernel/sched.c
@@ -26,8 +26,6 @@ void _schedule (void) {
     long                 next, c, cur;
     struct task_struct * p;
     while (1) {
-        printc ('-');
-        printc ('0' + nr_tasks);
         c    = -1;
         next = 0;
         cur;
@@ -41,7 +39,6 @@ void _schedule (void) {
             }
         }
         if (c) {
-            printc ('0' + cur);
             break;
         }
         for (int i = 0; i < NR_TASKS; i++) {
diff --git a/thorn/src/kernel/timer.c b/thorn/src/kernel/timer.c
index 79be217..0fe4556 100644
--- a/thorn/src/kernel/timer.c
+++ b/thorn/src/kernel/timer.c
@@ -15,7 +15,6 @@ void timer_init (void) {
 
 void handle_timer_irq (void) {
     toggle_led (STATUS_LED);
-    printc ('|');
 
     curVal += interval;
     put32 (TIMER_C1, curVal);

From 735eb1b3e231c496f54327bb8aaa164b9d70d1b3 Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Tue, 14 Dec 2021 14:26:04 +0100
Subject: [PATCH 20/21] fix(irq): move irq init into kernel_init

---
 thorn/src/kernel/kernel.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/thorn/src/kernel/kernel.c b/thorn/src/kernel/kernel.c
index cc95c6d..15d7abf 100644
--- a/thorn/src/kernel/kernel.c
+++ b/thorn/src/kernel/kernel.c
@@ -91,6 +91,11 @@ void kernel_init (void) {
             printf ("Height resolution: %d\r\n", get_fb_info ()->virtual_height);
         }
     }
+    irq_vector_init ();
+    timer_init ();
+    enable_interrupt_controller ();
+    enable_irq ();
+
     init_pages ();
 
     LOG ("Initialisation done");
@@ -112,10 +117,6 @@ void kernel_main (int processor_id) {
     //    current_processor++;
     //    while (current_processor != 4) {}
 
-    irq_vector_init ();
-    timer_init ();
-    enable_interrupt_controller ();
-    enable_irq ();
     CHECKPOINT
 
     switch (processor_id) {

From 3bcd28b0067328c7ae831aa91963d543ac63a99d Mon Sep 17 00:00:00 2001
From: Aaron Alef <aaron.alef@code.berlin>
Date: Tue, 14 Dec 2021 14:29:10 +0100
Subject: [PATCH 21/21] refactor(mmu): on data abort, kill offending process

---
 thorn/src/kernel/mmu.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/thorn/src/kernel/mmu.c b/thorn/src/kernel/mmu.c
index 79505ab..4d74945 100644
--- a/thorn/src/kernel/mmu.c
+++ b/thorn/src/kernel/mmu.c
@@ -142,24 +142,16 @@ void data_abort_el0 (ptr_t far, ptr_t esr, ptr_t elr) {
     switch (type) {
         case 0b00:// Address size fault
             printf ("Address size fault during level %u of table walk on lookup of address %p.\r\n", level, far);
-            //            exit_process ();
             break;
         case 0b01:// Translation fault
             printf ("Translation fault during level %u of table walk on lookup of address %p.\r\n", level, far);
-            asm volatile("msr ttbr0_el1, %0"
-                         :
-                         : "r"((unsigned long) &_end + TTBR_CNP));
-            asm volatile("dsb ish");
-            asm volatile("isb");
-            enable_irq ();
             break;
         case 0b10:// Access flag fault
             printf ("Access flag fault during level %u of table walk on lookup of address %p.\r\n", level, far);
-            //            exit_process ();
             break;
         case 0b11:// Permission fault
             printf ("Permission fault during level %u of table walk on lookup of address %p.\r\n", level, far);
-            //            exit_process ();
             break;
     }
+    exit_process ();
 }
\ No newline at end of file