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Date:   Mon, 13 Sep 2021 09:26:38 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Nathan Chancellor <nathan@kernel.org>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Joe Perches <joe@perches.com>, Arnd Bergmann <arnd@kernel.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>, llvm@lists.linux.dev,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 09/10] compiler-gcc.h: drop checks for older GCC versions
Message-ID: <202109130926.15C4D3486F@keescook>
References: <20210910234047.1019925-1-ndesaulniers@google.com>
 <20210910234047.1019925-10-ndesaulniers@google.com>
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On Fri, Sep 10, 2021 at 04:40:46PM -0700, Nick Desaulniers wrote:
> Now that GCC 5.1 is the minimally supported default, drop the values we
> don't use.
> 
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
>  include/linux/compiler-gcc.h       | 4 +---
>  tools/include/linux/compiler-gcc.h | 4 +---
>  2 files changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> index 3f7f6fa0e051..fd82ce169ce9 100644
> --- a/include/linux/compiler-gcc.h
> +++ b/include/linux/compiler-gcc.h
> @@ -98,10 +98,8 @@
>  
>  #if GCC_VERSION >= 70000
>  #define KASAN_ABI_VERSION 5
> -#elif GCC_VERSION >= 50000
> +#else
>  #define KASAN_ABI_VERSION 4
> -#elif GCC_VERSION >= 40902
> -#define KASAN_ABI_VERSION 3
>  #endif
>  
>  #if __has_attribute(__no_sanitize_address__)

Reviewed-by: Kees Cook <keescook@chromium.org>

> diff --git a/tools/include/linux/compiler-gcc.h b/tools/include/linux/compiler-gcc.h
> index a590a1dfafd9..43d9a46d36f0 100644
> --- a/tools/include/linux/compiler-gcc.h
> +++ b/tools/include/linux/compiler-gcc.h
> @@ -16,9 +16,7 @@
>  # define __fallthrough __attribute__ ((fallthrough))
>  #endif
>  
> -#if GCC_VERSION >= 40300
> -# define __compiletime_error(message) __attribute__((error(message)))
> -#endif /* GCC_VERSION >= 40300 */
> +#define __compiletime_error(message) __attribute__((error(message)))
>  
>  /* &a[0] degrades to a pointer: a different type from an array */
>  #define __must_be_array(a)	BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))

This part could be applied regardless (it's a missed 4.3 check, yes?)

-- 
Kees Cook