linux-kernel - Re: [PATCH 1/1] efi/libstub/x86: simplify efi_is

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Date:   Sun, 4 Oct 2020 16:14:11 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     Arvind Sankar <nivedita@...m.mit.edu>
Cc:     Brian Gerst <brgerst@...il.com>,
        Heinrich Schuchardt <xypron.glpk@....de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        "H . Peter Anvin" <hpa@...or.com>,
        linux-efi <linux-efi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] efi/libstub/x86: simplify efi_is_native()

On Sat, 3 Oct 2020 at 21:44, Arvind Sankar <nivedita@...m.mit.edu> wrote:
>
> On Sat, Oct 03, 2020 at 01:28:18PM -0400, Brian Gerst wrote:
> > On Sat, Oct 3, 2020 at 2:05 AM Heinrich Schuchardt <xypron.glpk@....de> wrote:
> > >
> > > CONFIG_EFI_MIXED depends on CONFIG_X86_64=y.
> > > There is no need to check CONFIG_X86_64 again.
> > >
> > > Signed-off-by: Heinrich Schuchardt <xypron.glpk@....de>
> > > ---
> > >  arch/x86/include/asm/efi.h | 2 --
> > >  1 file changed, 2 deletions(-)
> > >
> > > diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
> > > index b9c2667ac46c..ab28bf1c74cf 100644
> > > --- a/arch/x86/include/asm/efi.h
> > > +++ b/arch/x86/include/asm/efi.h
> > > @@ -223,8 +223,6 @@ static inline bool efi_is_64bit(void)
> > >
> > >  static inline bool efi_is_native(void)
> > >  {
> > > -       if (!IS_ENABLED(CONFIG_X86_64))
> > > -               return true;
> > >         return efi_is_64bit();
> > >  }
> >
> > This would then return false for native 32-bit.
> >
> > --
> > Brian Gerst
>
> 32-bit doesn't use this implementation: it's #define'd to true in
> drivers/firmware/efi/libstub/efistub.h.
>

Yes, and the reason this [now redundant] test exists is because this
did not use to be the case before

de8c55208c386 efi/libstub: Fix mixed mode boot issue after macro refactor

So for this patch

Acked-by: Ard Biesheuvel <ardb@...nel.org>

I'll queue this up