The critical fix: local_apic.rs id() now returns (read(0x20) >> 24) for xAPIC mode instead of the raw register value. This was causing wrong APIC IDs on Intel, leading to misrouted IPIs, missed TLB shootdowns, and the page fault during context switch at switch.rs:317.
Also adds:
- Named ICR constants (ICR_INIT_ASSERT, ICR_STARTUP) with bit-layout comments
- Comment documenting x2APIC timeout limitation (cpu_id allocated before timeout check)
- All existing changes preserved (x2APIC MADT type 9, cpuid split, memory alignment, RSDP checksum, ICR pending wait, MADT entry length guard)
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Derivative of Redox OS (https://www.redox-os.org) adding:
- AMD GPU driver (amdgpu) via LinuxKPI compat layer
- ext4 filesystem support (ext4d scheme daemon)
- ACPI fixes for AMD bare metal (x2APIC, DMAR, IVRS, MCFG)
- Custom branding (hostname, os-release, boot identity)
Build system is full upstream Redox with RBOS overlay in local/.
Patches for kernel, base, and relibc are symlinked from local/patches/
and protected from make clean/distclean. Custom recipes live in
local/recipes/ with symlinks into the recipes/ search path.
Build: make all CONFIG_NAME=redbear-full
Sync: ./local/scripts/sync-upstream.sh
vasilito