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From: Arvind Sankar <nivedita@alum.mit.edu>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Ard Biesheuvel <ardb@kernel.org>, Andrey Ignatov <rdna@fb.com>,
	linux-efi <linux-efi@vger.kernel.org>,
	bpf@vger.kernel.org
Subject: Re: [PATCH 05/24] efi/libstub: Optimize for size instead of speed
Date: Fri, 5 Jun 2020 09:32:32 -0400	[thread overview]
Message-ID: <20200605133232.GA616374@rani.riverdale.lan> (raw)
In-Reply-To: <20200605131419.GA560594@rani.riverdale.lan>

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@fb.com> wrote:
> > >
> > > Arvind Sankar <nivedita@alum.mit.edu> [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@alum.mit.edu>
> > > > ---
> > > >  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.

  reply	other threads:[~2020-06-05 13:32 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200518190716.751506-1-nivedita@alum.mit.edu>
     [not found] ` <20200518190716.751506-6-nivedita@alum.mit.edu>
2020-06-05  0:31   ` [PATCH 05/24] efi/libstub: Optimize for size instead of speed Andrey Ignatov
2020-06-05  6:33     ` Ard Biesheuvel
2020-06-05 13:14       ` Arvind Sankar
2020-06-05 13:32         ` Arvind Sankar [this message]
2020-06-05 14:53           ` Ard Biesheuvel
2020-06-05 15:10             ` Arvind Sankar
2020-06-05 15:11               ` Ard Biesheuvel
2020-06-05 15:06           ` [PATCH] efi/x86: Fix build with gcc 4 Arvind Sankar
2020-06-05 16:09             ` Andrey Ignatov
2020-06-15  9:43               ` Ard Biesheuvel

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