Re: [PATCH v3] kbuild: Use -fmin-function-alignment when available

[Masahiro Yamada]

On Thu, Feb 22, 2024 at 10:35 PM Petr Pavlu <petr.pavlu@xxxxxxxx> wrote:
>
> GCC recently added option -fmin-function-alignment, which should appear
> in GCC 14. Unlike -falign-functions, this option causes all functions to
> be aligned at the specified value, including the cold ones.
>
> In particular, when an arm64 kernel is built with
> DYNAMIC_FTRACE_WITH_CALL_OPS=y, the 8-byte function alignment is
> required for correct functionality. This was done by -falign-functions=8
> and having workarounds in the kernel to force the compiler to follow
> this alignment. The new -fmin-function-alignment option directly
> guarantees it.
>
> Detect availability of -fmin-function-alignment and use it instead of
> -falign-functions when present. Introduce CC_HAS_SANE_FUNCTION_ALIGNMENT
> and enable __cold to work as expected when it is set.
>
> Signed-off-by: Petr Pavlu <petr.pavlu@xxxxxxxx>
> Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
> Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
> ---





Applied to linux-kbuild.
Thanks.



-- 
Best Regards
Masahiro Yamada