linux-kernel - Re: [PATCH 1/3] compiler-gcc.h: Introduce _

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Message-ID: <CAKv+Gu_YjkGAjO1bM_eGFw8z3732y06M2EXfS7A34CaYkNdatA@mail.gmail.com>
Date:   Thu, 1 Feb 2018 17:30:43 +0000
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Herbert Xu <herbert@...dor.apana.org.au>,
        "David S . Miller" <davem@...emloft.net>,
        Christopher Li <sparse@...isli.org>,
        Tom Lendacky <thomas.lendacky@....com>,
        Arnd Bergmann <arnd@...db.de>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
        <linux-crypto@...r.kernel.org>,
        Linux-Sparse <linux-sparse@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] compiler-gcc.h: Introduce __optimize function attribute

On 1 February 2018 at 10:21, Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
> Create a new function attribute __optimize, which allows to specify an
> optimization level on a per-function basis.
>
> Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>

Acked-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>

> ---
> I assume this is supported as of gcc-4.4:
>   - gcc version 4.3.3 (GCC): warning: ‘__optimize__’ attribute directive
>     ignored
>   - gcc version 4.4.7 (Ubuntu/Linaro 4.4.7-1ubuntu2): OK
> ---
>  include/linux/compiler-gcc.h | 4 ++++
>  include/linux/compiler.h     | 4 ++++
>  2 files changed, 8 insertions(+)
>
> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> index 631354acfa720475..0a278a527944ad2f 100644
> --- a/include/linux/compiler-gcc.h
> +++ b/include/linux/compiler-gcc.h
> @@ -196,6 +196,10 @@
>  #endif /* __CHECKER__ */
>  #endif /* GCC_VERSION >= 40300 */
>
> +#if GCC_VERSION >= 40400
> +#define __optimize(level)      __attribute__((__optimize__(level)))
> +#endif /* GCC_VERSION >= 40400 */
> +
>  #if GCC_VERSION >= 40500
>
>  #ifndef __CHECKER__
> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
> index 52e611ab9a6cf6fd..5ff818e9a836e898 100644
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -271,6 +271,10 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
>
>  #endif /* __ASSEMBLY__ */
>
> +#ifndef __optimize
> +# define __optimize(level)
> +#endif
> +
>  /* Compile time object size, -1 for unknown */
>  #ifndef __compiletime_object_size
>  # define __compiletime_object_size(obj) -1
> --
> 2.7.4
>