[AArch64] Add support for pointer authentication relocations#801
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Shankar Easwaran (quic-seaswara) merged 1 commit intoFeb 25, 2026
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pzhengqc might be a better suited to review this. |
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Eli Friedman (@efriedma-quic) can you please review this change ? |
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Implements basic PAuth support for AArch64 following the PAuth ABI Extension specification (2025Q1): https://github.com/ARM-software/abi-aa/blob/main/pauthabielf64/pauthabielf64.rst **Adds:** - R_AARCH64_AUTH_ABS64 (0x244): authenticated absolute relocations - R_AARCH64_AUTH_RELATIVE (0x411): authenticated relative relocations **Testing:** Covers PIE/non-PIE/static executables, as well as various corner cases from the spec like undefined weak references, COPY relocations and non-allocating sections. **Not included:** GOT/PLT signing, additional AUTH relocation types (future work). **Notes:** I changed the way *GNULDBackend::recordRelativeReloc* store relative relocations. The original map is only iterated once (in a linear way), but reversing the key / values allows to implement an efficient *GNULDBackend::findRelativeReloc*. No changes to existing non-AUTH relocation behavior. Signed-off-by: Cedric Tessier <ctessier@qti.qualcomm.com>
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Shankar Easwaran (quic-seaswara)
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Shankar Easwaran (quic-seaswara)
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| ResolveInfo *rsym = pReloc.symInfo(); | ||
| Relocator::DWord A = pReloc.addend(); | ||
| Relocator::DWord S = pParent.getSymValue(&pReloc); | ||
| Relocator::Address targetVal = S + A; |
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It looks like this changes the behavior for non-pauth code: the value of "S" is modified by the code below (if (rsym && rsym->reserved() & Relocator::ReservePLT) etc.). I assume that's not intentional?
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No, this was never intended :(
I submitted a PR to fix this regression (#1334).
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Implements basic PAuth support for AArch64 following the PAuth ABI Extension specification (2025Q1):
https://github.com/ARM-software/abi-aa/blob/main/pauthabielf64/pauthabielf64.rst
Adds:
Testing:
Covers PIE/non-PIE/static executables, as well as various corner cases from the spec like undefined weak references, COPY relocations and non-allocating sections.
Not included:
GOT/PLT signing, additional AUTH relocation types (future work).
Notes:
I changed the way GNULDBackend::recordRelativeReloc store relative relocations. The original map is only iterated once (in a linear way), but reversing the key / values allows to implement an efficient GNULDBackend::findRelativeReloc.
No changes to existing non-AUTH relocation behavior.