On Fri, 5 Jun 2020 at 15:32, Arvind Sankar <nivedita@xxxxxxxxxxxx> wrote:
>
> On Fri, Jun 05, 2020 at 09:14:19AM -0400, Arvind Sankar wrote:
> > On Fri, Jun 05, 2020 at 08:33:22AM +0200, Ard Biesheuvel wrote:
> > > Hello Andrey,
> > >
> > > On Fri, 5 Jun 2020 at 02:31, Andrey Ignatov <rdna@xxxxxx> wrote:
> > > >
> > > > Arvind Sankar <nivedita@xxxxxxxxxxxx> [Wed, 1969-12-31 23:00 -0800]:
> > > > > Reclaim the bloat from the addition of printf by optimizing the stub for
> > > > > size. With gcc 9, the text size of the stub is:
> > > > >
> > > > > ARCH before +printf -Os
> > > > > arm 35197 37889 34638
> > > > > arm64 34883 38159 34479
> > > > > i386 18571 21657 17025
> > > > > x86_64 25677 29328 22144
> > > > >
> > > > > Signed-off-by: Arvind Sankar <nivedita@xxxxxxxxxxxx>
> > > > > ---
> > > > > drivers/firmware/efi/libstub/Makefile | 4 ++--
> > > > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > > > >
> > > > > diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
> > > > > index fb34c9d14a3c..034d71663b1e 100644
> > > > > --- a/drivers/firmware/efi/libstub/Makefile
> > > > > +++ b/drivers/firmware/efi/libstub/Makefile
> > > > > @@ -7,7 +7,7 @@
> > > > > #
> > > > > cflags-$(CONFIG_X86_32) := -march=i386
> > > > > cflags-$(CONFIG_X86_64) := -mcmodel=small
> > > > > -cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ -O2 \
> > > > > +cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ \
> > > > > -fPIC -fno-strict-aliasing -mno-red-zone \
> > > > > -mno-mmx -mno-sse -fshort-wchar \
> > > > > -Wno-pointer-sign \
> > > > > @@ -25,7 +25,7 @@ cflags-$(CONFIG_ARM) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
> > > > >
> > > > > cflags-$(CONFIG_EFI_GENERIC_STUB) += -I$(srctree)/scripts/dtc/libfdt
> > > > >
> > > > > -KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \
> > > > > +KBUILD_CFLAGS := $(cflags-y) -Os -DDISABLE_BRANCH_PROFILING \
> > > > > -include $(srctree)/drivers/firmware/efi/libstub/hidden.h \
> > > > > -D__NO_FORTIFY \
> > > > > $(call cc-option,-ffreestanding) \
> > > >
> > > > Hi Arvind,
> > > >
> > > > This patch breaks build for me:
> > > >
> > > > $>make -j32 -s bzImage
> > > > drivers/firmware/efi/libstub/alignedmem.c: In function \x2018efi_allocate_pages_aligned\x2019:
> > > > drivers/firmware/efi/libstub/alignedmem.c:38:9: sorry, unimplemented: ms_abi attribute requires -maccumulate-outgoing-args or subtarget optimization implying it
> > > > status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
> > > > ^
> > >
> > > Which version of GCC are you using?
> >
> > gcc-4.8.5 from the config. I got a copy and can reproduce it. Just
> > adding -maccumulate-outgoing-args appears to fix it, checking some more.
> >
>
> On a simple test:
> extern void __attribute__ (( ms_abi )) ms_abi();
> void sysv_abi(void) { ms_abi(); }
> it only breaks with -Os -fno-asynchronous-unwind-tables, weirdly enough.
I guess the logic that decides whether -maccumulate-outgoing-args is
enabled is somewhat opaque.
Could we perhaps back out the -Os change for 4.8 and earlier?
