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amd64: fix GOT-indirect addressing bug in dictionary fast-path lookup

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vm_find_word() and dict_find_word_heat_aware() reference the same extern
globals (sf_fc_list/sf_fc_count/sf_fc_cap) but GCC compiled cross-TU
references to them with GOT-indirect addressing (R_X86_64_REX_GOTPCRELX)
under -fPIC. This freestanding, statically-linked UEFI PE image has no
dynamic linker to populate a GOT, so those reads silently returned NULL
instead of the array's real address -- amd64-only, and exquisitely
sensitive to unrelated code-size changes since the choice between direct
and GOT-indirect addressing is a per-call-site GCC heuristic.

Fix: -fno-pic -fno-pie for amd64 only (ARCH_CFLAGS, overriding
COMMON_CFLAGS's -fPIC, which riscv64's -shared loader link still needs).
Also removes -DPLATFORM_TIME_NO_INLINE, a prior one-off workaround for
the identical bug applied to sf_monotonic_ns() specifically, now
redundant. Adds R_X86_64_PC32/R_X86_64_PLT32 handling to
elf_apply_relocations() as a robustness fix for the non-monolithic
split-build path (dead code for the current monolithic boot, where OVMF's
own PE loader relocates the image, not this loader).

Verified: all three architectures boot clean and pass the full item-4.2
Hermes self-test, including MSG-DELIVER-ALL, which previously triggered
the corruption on amd64 only. Write-up in FABRIC.md under item 4.2.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
This commit is contained in:
Robert Allan James
2026-08-06 21:18:06 -04:00
co-authored by Claude Sonnet 5
parent 56ad128e2e
commit 0a7f144367
4 changed files with 107 additions and 7 deletions
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src/starkernel/boot/elf_loader.c
+17
View File
@@ -226,6 +226,10 @@ static int elf_load_segments(const uint8_t *elf_data, Elf64_Addr load_base)
* - @c R_X86_64_RELATIVE — absolute address = @c load_base + @c r_addend.
* - @c R_X86_64_64 — @c load_base + symbol value + @c r_addend (64-bit).
* - @c R_X86_64_32 / @c R_X86_64_32S — same, truncated to 32 bits.
* - @c R_X86_64_PC32 / @c R_X86_64_PLT32 — @c symbol + @c r_addend - P
* (PC-relative, 32 bits), where P is the relocation's own runtime
* address; PLT32 has no real PLT indirection in this static, non-PIE
* link, so it resolves the same as PC32.
*
* - **aarch64 (@c ARCH_AARCH64)**:
* - @c R_AARCH64_NONE — no-op.
@@ -301,6 +305,19 @@ static int elf_apply_relocations(const uint8_t *elf_data, Elf64_Addr load_base)
*target32 = (uint32_t)value;
break;
}
case R_X86_64_PC32:
case R_X86_64_PLT32: {
/* value = S + A - P, where P is the address of the relocation
* itself (reloc_addr already includes load_base). PLT32 is
* treated identically to PC32: this is a static, non-PIE
* link with every symbol resolved in-image, so there is no
* real PLT indirection to apply. */
uint32_t *target32 = (uint32_t *)reloc_addr;
int64_t value = (int64_t)(load_base + sym_value + rela[j].r_addend) -
(int64_t)reloc_addr;
*target32 = (uint32_t)value;
break;
}
default:
return 0;
}