VDSO LELO

arch/arm64/Kconfig

@@ -1326,6 +1326,14 @@ config COMPAT_VDSO
 	  You must have a 32-bit build of glibc 2.22 or later for programs
 	  to seamlessly take advantage of this.
 
+config THUMB2_COMPAT_VDSO
+	bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
+	depends on COMPAT_VDSO
+	default y
+	help
+	  Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
+	  otherwise with '-marm'.
+
 menuconfig ARMV8_DEPRECATED
 	bool "Emulate deprecated/obsolete ARMv8 instructions"
 	depends on SYSCTL

arch/arm64/Makefile

@@ -177,6 +177,8 @@ vdso_install:
 # We use MRPROPER_FILES and CLEAN_FILES now
 archclean:
 	$(Q)$(MAKE) $(clean)=$(boot)
+	$(Q)$(MAKE) $(clean)=arch/arm64/kernel/vdso
+	$(Q)$(MAKE) $(clean)=arch/arm64/kernel/vdso32
 
 ifeq ($(KBUILD_EXTMOD),)
 # We need to generate vdso-offsets.h before compiling certain files in kernel/.
@@ -187,10 +189,12 @@ ifeq ($(KBUILD_EXTMOD),)
 # this hack.
 prepare: vdso_prepare
 vdso_prepare: prepare0
-	$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso include/generated/vdso-offsets.h
-	$(if $(CONFIG_COMPAT_VDSO),$(Q)$(MAKE) \
-		$(build)=arch/arm64/kernel/vdso32  \
-		include/generated/vdso32-offsets.h)
+	$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso \
+	include/generated/vdso-offsets.h arch/arm64/kernel/vdso/vdso.so
+ifdef CONFIG_COMPAT_VDSO
+	$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso32 \
+	include/generated/vdso32-offsets.h arch/arm64/kernel/vdso32/vdso.so
+endif
 endif
 
 define archhelp

arch/arm64/include/asm/mmu.h

@@ -18,6 +18,9 @@
 
 typedef struct {
 	atomic64_t	id;
+#ifdef CONFIG_COMPAT
+	void		*sigpage;
+#endif
 	void		*vdso;
 	unsigned long	flags;
 } mm_context_t;

arch/arm64/include/asm/vdso/compat_barrier.h

@@ -20,16 +20,9 @@
 
 #define dmb(option) __asm__ __volatile__ ("dmb " #option : : : "memory")
 
-#if __LINUX_ARM_ARCH__ >= 8 && defined(CONFIG_AS_DMB_ISHLD)
 #define aarch32_smp_mb()	dmb(ish)
 #define aarch32_smp_rmb()	dmb(ishld)
 #define aarch32_smp_wmb()	dmb(ishst)
-#else
-#define aarch32_smp_mb()	dmb(ish)
-#define aarch32_smp_rmb()	aarch32_smp_mb()
-#define aarch32_smp_wmb()	dmb(ishst)
-#endif
-
 
 #undef smp_mb
 #undef smp_rmb

arch/arm64/kernel/Makefile

@@ -29,9 +29,7 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
 
 obj-$(CONFIG_COMPAT)			+= sys32.o signal32.o			\
 					   sys_compat.o
-ifneq ($(CONFIG_COMPAT_VDSO), y)
 obj-$(CONFIG_COMPAT)			+= sigreturn32.o
-endif
 obj-$(CONFIG_KUSER_HELPERS)		+= kuser32.o
 obj-$(CONFIG_FUNCTION_TRACER)		+= ftrace.o entry-ftrace.o
 obj-$(CONFIG_MODULES)			+= module.o
@@ -65,9 +63,14 @@ obj-$(CONFIG_ARM_SDE_INTERFACE)		+= sdei.o
 obj-$(CONFIG_ARM64_SSBD)		+= ssbd.o
 obj-$(CONFIG_ARM64_PTR_AUTH)		+= pointer_auth.o
 obj-$(CONFIG_SHADOW_CALL_STACK)		+= scs.o
+obj-y			          	+= vdso-wrap.o
+obj-$(CONFIG_COMPAT_VDSO)		+= vdso32-wrap.o
+
+# Force dependency (vdso*-wrap.S includes vdso.so through incbin)
+$(obj)/vdso-wrap.o: $(obj)/vdso/vdso.so
+$(obj)/vdso32-wrap.o: $(obj)/vdso32/vdso.so
 
-obj-y					+= vdso/ probes/
-obj-$(CONFIG_COMPAT_VDSO)		+= vdso32/
+obj-y					+= probes/
 head-y					:= head.o
 extra-y					+= $(head-y) vmlinux.lds
 

arch/arm64/kernel/signal32.c

@@ -342,38 +342,13 @@ static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 		retcode = ptr_to_compat(ka->sa.sa_restorer);
 	} else {
 		/* Set up sigreturn pointer */
-#ifdef CONFIG_COMPAT_VDSO
-		void *vdso_base = current->mm->context.vdso;
-		void *vdso_trampoline;
-
-		if (ka->sa.sa_flags & SA_SIGINFO) {
-			if (thumb) {
-				vdso_trampoline = VDSO_SYMBOL(vdso_base,
-							compat_rt_sigreturn_thumb);
-			} else {
-				vdso_trampoline = VDSO_SYMBOL(vdso_base,
-							compat_rt_sigreturn_arm);
-			}
-		} else {
-			if (thumb) {
-				vdso_trampoline = VDSO_SYMBOL(vdso_base,
-							compat_sigreturn_thumb);
-			} else {
-				vdso_trampoline = VDSO_SYMBOL(vdso_base,
-							compat_sigreturn_arm);
-			}
-		}
-
-		retcode = ptr_to_compat(vdso_trampoline) + thumb;
-#else
 		unsigned int idx = thumb << 1;
 
 		if (ka->sa.sa_flags & SA_SIGINFO)
 			idx += 3;
 
-		retcode = (unsigned long)current->mm->context.vdso +
+		retcode = (unsigned long)current->mm->context.sigpage +
 			  (idx << 2) + thumb;
-#endif
 	}
 
 	regs->regs[0]	= usig;