Re: [PATCH 1/2] x86/efi: Optimize away setup_gop32/64 if unused

Lukas Wunner
2016-09-06T06:10:07Z

On Mon, Sep 05, 2016 at 01:37:25PM +0100, Matt Fleming wrote:
> On Mon, 22 Aug, at 12:01:21PM, Lukas Wunner wrote:
> > Eliminate the 64 bit code path when compiling for x86_32, and vice-versa
> > the 32 bit code path when compiling for x86_64 with mixed mode disabled.
> >
> > Size of gop.o text section:
> > CONFIG_X86_32: 1758 before, 1299 after
> > CONFIG_X86_64 && !CONFIG_EFI_MIXED: 2201 before, 1406 after
> > CONFIG_X86_64 && CONFIG_EFI_MIXED: 2201 before and after
> >
> > Signed-off-by: Lukas Wunner <lukas@wunner.de>
> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > ---
> > arch/x86/include/asm/efi.h | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
> > index 6b06939..1bda245 100644
> > --- a/arch/x86/include/asm/efi.h
> > +++ b/arch/x86/include/asm/efi.h
> > @@ -207,14 +207,16 @@ struct efi_config {
> >
> > __pure const struct efi_config *__efi_early(void);
> >
> > +#define efi_is_64bit() \
> > + (IS_ENABLED(CONFIG_X86_64) && (!IS_ENABLED(CONFIG_EFI_MIXED) \
> > + || __efi_early()->is64))
> > +
> > #define efi_call_early(f, ...) \
> > __efi_early()->call(__efi_early()->f, __VA_ARGS__);
> >
> > #define __efi_call_early(f, ...) \
> > __efi_early()->call((unsigned long)f, __VA_ARGS__);
> >
> > -#define efi_is_64bit() __efi_early()->is64
> > -
> > extern bool efi_reboot_required(void);
> >
> > #else
>
> Could you make this into a more readable static inline? e.g. something
> like this,
>
> static inline bool efi_is_64bit(void)
> {
> if (!IS_ENABLED(CONFIG_X86_64))
> return false;
>
> if (!IS_ENABLED(CONFIG_EFI_MIXED) || __efi_early()->is64)
> return true;
>
> return false;
> }

Indeed this is much better. I've just sent out an updated version
in-reply-to the original patch.

Thanks a lot,

Lukas