On Mon, 21 Jun 2021 16:18:19 -0700, Nick Desaulniers wrote:
> The kernel has been using noinstr for correctness to politely request
> that the compiler avoid adding various forms of instrumentation to
> certain functions.
>
> GCOV and PGO can both instrument functions, yet the function attribute
> to disable such instrumentation (no_profile_instrument_function) was not
> being used to suppress such implementation. Also, clang only just
> recently gained support for no_profile_instrument_function. GCC has
> supported that since 7.1+.
>
> [...]
Applied to for-next/clang/features, thanks!
[1/3] compiler_attributes.h: define __no_profile, add to noinstr
https://git.kernel.org/kees/c/380d53c45ff2
[2/3] compiler_attributes.h: cleanups for GCC 4.9+
https://git.kernel.org/kees/c/ae4d682dfd33
[3/3] Kconfig: add ARCH_WANTS_NO_INSTR+CC_HAS_NO_PROFILE_FN_ATTR, depend on for GCOV and PGO
https://git.kernel.org/kees/c/51c2ee6d121c
Note that I've tweaked the series slightly to move the PGO Kconfig change into
the PGO patch.
--
Kees Cook
