Arvind Sankar <nivedita@xxxxxxxxxxxx> [Fri, 2020-06-05 08:06 -0700]:
> Commit
> bbf8e8b0fe04 ("efi/libstub: Optimize for size instead of speed")
>
> changed the optimization level for the EFI stub to -Os from -O2.
>
> Andrey Ignatov reports that this breaks the build with gcc 4.8.5.
>
> Testing on godbolt.org, the combination of -Os,
> -fno-asynchronous-unwind-tables, and ms_abi functions doesn't work,
> failing with the error:
> sorry, unimplemented: ms_abi attribute requires
> -maccumulate-outgoing-args or subtarget optimization implying it
>
> This does appear to work with gcc 4.9 onwards.
>
> Add -maccumulate-outgoing-args explicitly to unbreak the build with
> pre-4.9 versions of gcc.
>
> Reported-by: Andrey Ignatov <rdna@xxxxxx>
> Signed-off-by: Arvind Sankar <nivedita@xxxxxxxxxxxx>
Thanks. I confirmed it fixes the problem on my setup with gcc 4.8.5 and
also works as before with clang 9.0.20190721.
> ---
> drivers/firmware/efi/libstub/Makefile | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
> index cce4a7436052..d67418de768c 100644
> --- a/drivers/firmware/efi/libstub/Makefile
> +++ b/drivers/firmware/efi/libstub/Makefile
> @@ -6,7 +6,8 @@
> # enabled, even if doing so doesn't break the build.
> #
> cflags-$(CONFIG_X86_32) := -march=i386
> -cflags-$(CONFIG_X86_64) := -mcmodel=small
> +cflags-$(CONFIG_X86_64) := -mcmodel=small \
> + $(call cc-option,-maccumulate-outgoing-args)
> cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ \
> -fPIC -fno-strict-aliasing -mno-red-zone \
> -mno-mmx -mno-sse -fshort-wchar \
> --
> 2.26.2
>
--
Andrey Ignatov
