Re: [PATCH v2 1/4] x86: Use the default ABI for the 32-bit vDSO

From: Stefani Seibold
Date: Fri Feb 28 2014 - 02:28:56 EST


Am Donnerstag, den 27.02.2014, 16:18 -0800 schrieb Andy Lutomirski:
> There's no reason for the vDSO to use a special function call ABI. Use
> the platform defaults.
>

The only reason was performance. What is good for the kernel should be
also good for the VDSO. Now all functions inside the VDSO will pass the
arguments by stack.

> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> ---
> arch/x86/vdso/Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
> index 92daaa6..80584f5 100644
> --- a/arch/x86/vdso/Makefile
> +++ b/arch/x86/vdso/Makefile
> @@ -149,7 +149,7 @@ KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
> KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
> KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
> KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
> -KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=3 -freg-struct-return -fpic
> +KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
> $(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
>
> $(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \


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