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Date:   Mon, 31 Aug 2020 21:57:53 -0700
From:   Nathan Chancellor <natechancellor@gmail.com>
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
        Sedat Dilek <sedat.dilek@gmail.com>,
        Marco Elver <elver@google.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        clang-built-linux@googlegroups.com,
        Daniel Borkmann <daniel@iogearbox.net>,
        Alexei Starovoitov <ast@kernel.org>,
        Will Deacon <will@kernel.org>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 6/7] kasan: Remove mentions of unsupported Clang
 versions
Message-ID: <20200901045753.GE1561318@ubuntu-n2-xlarge-x86>
References: <20200901002326.1137289-1-ndesaulniers@google.com>
 <20200901002326.1137289-7-ndesaulniers@google.com>
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On Mon, Aug 31, 2020 at 05:23:25PM -0700, Nick Desaulniers wrote:
> From: Marco Elver <elver@google.com>
> 
> Since the kernel now requires at least Clang 10.0.1, remove any mention
> of old Clang versions and simplify the documentation.
> 
> Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
> Signed-off-by: Marco Elver <elver@google.com>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>

> ---
>  Documentation/dev-tools/kasan.rst | 4 ++--
>  lib/Kconfig.kasan                 | 9 ++++-----
>  2 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
> index 38fd5681fade..4abc84b1798c 100644
> --- a/Documentation/dev-tools/kasan.rst
> +++ b/Documentation/dev-tools/kasan.rst
> @@ -13,10 +13,10 @@ KASAN uses compile-time instrumentation to insert validity checks before every
>  memory access, and therefore requires a compiler version that supports that.
>  
>  Generic KASAN is supported in both GCC and Clang. With GCC it requires version
> -8.3.0 or later. With Clang it requires version 7.0.0 or later, but detection of
> +8.3.0 or later. Any supported Clang version is compatible, but detection of
>  out-of-bounds accesses for global variables is only supported since Clang 11.
>  
> -Tag-based KASAN is only supported in Clang and requires version 7.0.0 or later.
> +Tag-based KASAN is only supported in Clang.
>  
>  Currently generic KASAN is supported for the x86_64, arm64, xtensa, s390 and
>  riscv architectures, and tag-based KASAN is supported only for arm64.
> diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
> index 047b53dbfd58..033a5bc67ac4 100644
> --- a/lib/Kconfig.kasan
> +++ b/lib/Kconfig.kasan
> @@ -54,9 +54,9 @@ config KASAN_GENERIC
>  	  Enables generic KASAN mode.
>  
>  	  This mode is supported in both GCC and Clang. With GCC it requires
> -	  version 8.3.0 or later. With Clang it requires version 7.0.0 or
> -	  later, but detection of out-of-bounds accesses for global variables
> -	  is supported only since Clang 11.
> +	  version 8.3.0 or later. Any supported Clang version is compatible,
> +	  but detection of out-of-bounds accesses for global variables is
> +	  supported only since Clang 11.
>  
>  	  This mode consumes about 1/8th of available memory at kernel start
>  	  and introduces an overhead of ~x1.5 for the rest of the allocations.
> @@ -78,8 +78,7 @@ config KASAN_SW_TAGS
>  	  Enables software tag-based KASAN mode.
>  
>  	  This mode requires Top Byte Ignore support by the CPU and therefore
> -	  is only supported for arm64. This mode requires Clang version 7.0.0
> -	  or later.
> +	  is only supported for arm64. This mode requires Clang.
>  
>  	  This mode consumes about 1/16th of available memory at kernel start
>  	  and introduces an overhead of ~20% for the rest of the allocations.
> -- 
> 2.28.0.402.g5ffc5be6b7-goog
>