fix(aarch64): cpuid retrieved by boot_cpuid_get is corrupted in release mode
#226
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Pull request overview
This PR fixes a critical bug in the AArch64 boot code where the CPU ID value was being corrupted in release mode. The issue stems from using x17 (IP1, an intra-procedure-call temporary register) to store the CPU ID across multiple function calls. In release mode, x17 can be clobbered by compiler optimizations, linker veneers, or PLT stubs, causing the CPU ID value to be lost or corrupted.
The fix systematically replaces all instances of x17 with x19, a callee-saved register that is guaranteed to be preserved across function calls according to the ARM64 ABI.
- Replaced x17 with x19 in
boot_cpuid_get()function for storing and returning the CPU ID - Updated all x17 references in
arch_entry()to use x19 for cpuid calculations and comparisons - Ensured the register is properly cleared after use before jumping to
rust_main
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enkerewpo
approved these changes
Dec 15, 2025
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Fixes #225