Add support for system management syscalls

[kov]

Implements restart_syscall and kexec_load from Batch 11 (Legacy & Misc).

restart_syscall:

• Kernel-internal syscall for resuming interrupted syscalls
• Takes no arguments
• Returns 0 on success

kexec_load:

• Load new kernel for execution (kexec mechanism)
• Arguments: entry point, nr_segments, segments pointer, flags
• Flags include KEXEC_ON_CRASH, KEXEC_PRESERVE_CONTEXT, and architecture constants (KEXEC_ARCH_X86_64, KEXEC_ARCH_AARCH64, etc.)
• Added kexec_constants module with all flag definitions from linux/include/uapi/linux/kexec.h
• Created format_kexec_load_flags() helper for pretty-printing flags
• Returns 0 on success

Added 4 pretty printing tests covering both syscalls and various flag combinations.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR adds support for two system management syscalls: restart_syscall and kexec_load. The restart_syscall is a simple kernel-internal syscall with no arguments, while kexec_load is more complex, handling kernel loading with memory segments and various flags including architecture-specific constants. The implementation includes comprehensive flag formatting with support for multiple architectures, segment parsing in the eBPF handler, and 4 tests covering different scenarios.

Key Changes

• Added restart_syscall syscall support (no arguments)
• Added kexec_load syscall with full argument parsing including segments array and flags
• Created kexec_constants module with KEXEC flags and architecture constants
• Implemented format_kexec_load_flags() helper for pretty-printing flags

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
pinchy/src/tests/system.rs	Added 4 tests covering restart_syscall and kexec_load with various flag combinations and segment parsing
pinchy/src/server.rs	Registered both syscalls in the SYSTEM_SYSCALLS array for the system handler
pinchy/src/format_helpers.rs	Added kexec_constants module and format_kexec_load_flags() function, plus return value formatting
pinchy/src/events.rs	Added parsing logic for both syscalls, with detailed segment array formatting for kexec_load
pinchy-ebpf/src/system.rs	Added eBPF handlers for both syscalls, including segment reading logic for kexec_load
pinchy-common/src/lib.rs	Added RestartSyscallData and KexecLoadData structures to the union
pinchy-common/src/kernel_types.rs	Added KexecSegment struct and KEXEC_SEGMENT_ARRAY_CAP constant