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Tue, 13 Oct 2020 23:47:53 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1825321D81; Tue, 13 Oct 2020 23:47:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602632872; bh=17gTM3q2sumStLGXtQqsRWHvZJ0nie+65KOyyU3pdiU=; h=Date:From:To:Subject:In-Reply-To:From; b=L6zaA4/id/8hkjOipSSQ4/4pfVoqRoqFKxQRf3cWJtaLTaFkNEE7Fy76gx8X+ve7v jfQRFpPYddbr9lYE/o7AF9aYPmPWB97uB7Uyc2ekVQ2sjqu9JV4oYZhBwLIRGXVgoI RYDlKJ9XGD3XXrq6JirrnpT6WQJEesOy0m9QV+9A= Date: Tue, 13 Oct 2020 16:47:51 -0700 From: Andrew Morton To: akpm@linux-foundation.org, andreyknvl@google.com, ast@kernel.org, daniel@iogearbox.net, elver@google.com, keescook@chromium.org, linux-mm@kvack.org, masahiroy@kernel.org, maskray@google.com, miguel.ojeda.sandonis@gmail.com, mm-commits@vger.kernel.org, natechancellor@gmail.com, ndesaulniers@google.com, sedat.dilek@gmail.com, torvalds@linux-foundation.org, vincenzo.frascino@arm.com, will@kernel.org Subject: [patch 006/181] kasan: remove mentions of unsupported Clang versions Message-ID: <20201013234751.9pYJWzf66%akpm@linux-foundation.org> In-Reply-To: <20201013164658.3bfd96cc224d8923e66a9f4e@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Marco Elver Subject: kasan: remove mentions of unsupported Clang versions Since the kernel now requires at least Clang 10.0.1, remove any mention of old Clang versions and simplify the documentation. Link: https://lkml.kernel.org/r/20200902225911.209899-7-ndesaulniers@google.com Signed-off-by: Marco Elver Signed-off-by: Nick Desaulniers Reviewed-by: Andrey Konovalov Reviewed-by: Kees Cook Reviewed-by: Nathan Chancellor Cc: Fangrui Song Cc: Miguel Ojeda Cc: Sedat Dilek Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Masahiro Yamada Cc: Vincenzo Frascino Cc: Will Deacon Signed-off-by: Andrew Morton --- Documentation/dev-tools/kasan.rst | 4 ++-- lib/Kconfig.kasan | 9 ++++----- 2 files changed, 6 insertions(+), 7 deletions(-) --- a/Documentation/dev-tools/kasan.rst~kasan-remove-mentions-of-unsupported-clang-versions +++ a/Documentation/dev-tools/kasan.rst @@ -13,10 +13,10 @@ KASAN uses compile-time instrumentation 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. --- a/lib/Kconfig.kasan~kasan-remove-mentions-of-unsupported-clang-versions +++ a/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.