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From: Arvind Sankar <nivedita@alum.mit.edu>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-efi@vger.kernel.org, luto@kernel.org, x86@kernel.org,
	nivedita@alum.mit.edu
Subject: Re: [PATCH 1/2] efi/libstub/x86: use const attribute for efi_is_64bit()
Date: Wed, 8 Jan 2020 10:23:26 -0500	[thread overview]
Message-ID: <20200108152325.GA2499882@rani.riverdale.lan> (raw)
In-Reply-To: <20200108074502.10960-2-ardb@kernel.org>

On Wed, Jan 08, 2020 at 08:45:01AM +0100, Ard Biesheuvel wrote:
> Reshuffle the x86 stub code a bit so that we can tag the efi_is_64bit()
> function with the 'const' attribute, which permits the compiler to
> optimize away any redundant calls. Since we have two different entry
> points for 32 and 64 bit firmware in the startup code, this also
> simplifies the C code since we'll enter it with the efi_is64 variable
> already set.
> 
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
>  arch/x86/boot/compressed/eboot.c   | 14 ++++++--------
>  arch/x86/boot/compressed/head_64.S |  7 +++----
>  arch/x86/include/asm/efi.h         |  2 +-
>  3 files changed, 10 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
> index 4afd29eb5b34..ab3a40283db7 100644
> --- a/arch/x86/boot/compressed/eboot.c
> +++ b/arch/x86/boot/compressed/eboot.c
> @@ -21,16 +21,18 @@
>  #include "eboot.h"
>  
>  static efi_system_table_t *sys_table;
> -static bool efi_is64 = IS_ENABLED(CONFIG_X86_64);
> +extern const bool efi_is64;
>  

Didn't we need to declare this with hidden visibility? Or use the
#pragma GCC visibility push(hidden)?

  reply	other threads:[~2020-01-08 15:23 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-08  7:45 [PATCH 0/2] efi/libstub/x86: two more tweaks for the EFI stub startup code Ard Biesheuvel
2020-01-08  7:45 ` [PATCH 1/2] efi/libstub/x86: use const attribute for efi_is_64bit() Ard Biesheuvel
2020-01-08 15:23   ` Arvind Sankar [this message]
2020-01-08 15:25     ` Ard Biesheuvel
2020-01-08 15:25       ` Ard Biesheuvel
2020-01-08 15:27         ` Arvind Sankar
2020-01-08  7:45 ` [PATCH 2/2] efi/libstub/x86: use mandatory 16-byte stack alignment in mixed mode Ard Biesheuvel

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