[AArch64][BTI] Add BTI hint + GNU property to fcontext trampolines #312
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olk merged 1 commit intoboostorg:developfrom Aug 26, 2025
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[AArch64][BTI] Add BTI hint + GNU property to fcontext trampolines #312olk merged 1 commit intoboostorg:developfrom
olk merged 1 commit intoboostorg:developfrom
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…LF/GAS) The AArch64 fcontext trampolines (jump_fcontext, make_fcontext, ontop_fcontext) are indirect-entry-points. On BTI-enforcing systems they must begin with a BTI or the first resume can trap with SIGILL. Insert `bti c` (hint boostorg#34) at each entry under `__ARM_FEATURE_BTI_DEFAULT`, and emit `GNU_PROPERTY_AARCH64_FEATURE_1_BTI` from each AArch64 assembly file so linkers map the DSO with PROT_BTI without requiring -z force-bti. Scope: ELF/GAS AArch64 trampolines only; +4 bytes per entry Fixes boostorg#308
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Add BTI hint + GNU property to fcontext trampolines
The AArch64 fcontext trampolines (jump_fcontext, make_fcontext, ontop_fcontext) are indirect-entry-points. On BTI-enforcing systems they must begin with a BTI or the first resume can trap with SIGILL.
Insert
bti c(hint #34) at each entry under__ARM_FEATURE_BTI_DEFAULT, and emitGNU_PROPERTY_AARCH64_FEATURE_1_BTIfrom each AArch64 assembly file so linkers map the DSO with PROT_BTI.Scope: ELF/GAS AArch64 trampolines only; +4 bytes per entry
Fixes #308
Notes
bti jissue #149267; exception paths built with affected Clang toolchains will still require the upstream fix.