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> --- 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