From patchwork Mon Dec 2 17:33:23 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Mailhol via B4 Relay X-Patchwork-Id: 13891137 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4C6FE1D90B3; Mon, 2 Dec 2024 17:35:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733160904; cv=none; b=hnyINPmjWfycBzQGJe8VPx1ae7P7YpRPojJr3ELsEa2fiGHrrXCcL5yJJdMb9gyvcEVHz13embUNO3QW5YMd/5jBQtNYPHV+C1bvVe9of/Np1JAAp8Qp8oI5UBgjAKc2lPvVNxD5RFFyjmJJIhvt4cbTe+5zOyS8JjZByVNDt/g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733160904; c=relaxed/simple; bh=5SkdVpyxMkwcefHUvrmeRmooVspzWLLjyCNkLAyYF/4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=JlYSDkUvLpeILBF+771Th+HASIVKqkavtmXhk0lskC5/c7TAzlz1H41IWjBOoiuTIqP8hkcC8tXAcm961M0aC8P7aCxR0wCvXmOO0hj5i0hEDparm7DRjnEpdRKEj6paLzyIlSMzIlNxFBrIqut93Hk+fP8gLvgrTwdOFd+sNzE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=krYcOchp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="krYcOchp" Received: by smtp.kernel.org (Postfix) with ESMTPS id EB054C4CED6; Mon, 2 Dec 2024 17:35:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733160904; bh=5SkdVpyxMkwcefHUvrmeRmooVspzWLLjyCNkLAyYF/4=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=krYcOchpdZfTOGmmZmYXGkkzng0VBYzBaTIPS/JdWNiJdmt/4S7+V2deZeuJtDiHJ 5bOfjWx9PMCJkw4vWMJA+j7RGJgyQT3MCvZz+ywWGgXkUPQ1I8zhp2RRNDd7wmPgUC KVr3TdRx7r3vS7sNZQQ4VuZSeMJ1Co4MyFc7SbZRWDfa4cIk4lQ19T0FRsrpwOa17T JopKvCO/OnNKT3V7n07PfE9Ll3My7kWEoWbthp4JMgarfO7M35ovTZ+SUQIDeAkdh8 VxQs0KDQFLoqYMNE9XZ9vIlYg+Eia5POewyoXqK+ltXanlAIbCfNk8+zvx51tcJKic OeLS9BafEnm7Q== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2CC9D7833C; Mon, 2 Dec 2024 17:35:03 +0000 (UTC) From: Vincent Mailhol via B4 Relay Date: Tue, 03 Dec 2024 02:33:23 +0900 Subject: [PATCH 01/10] compiler.h: add statically_false() Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241203-is_constexpr-refactor-v1-1-4e4cbaecc216@wanadoo.fr> References: <20241203-is_constexpr-refactor-v1-0-4e4cbaecc216@wanadoo.fr> In-Reply-To: <20241203-is_constexpr-refactor-v1-0-4e4cbaecc216@wanadoo.fr> To: Linus Torvalds , David Laight , Luc Van Oostenryck , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Yury Norov , Rasmus Villemoes , Kees Cook , "Gustavo A. R. Silva" , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , David Airlie , Simona Vetter , Suzuki K Poulose , Mike Leach , James Clark , Alexander Shishkin , Rikard Falkeborn , Martin Uecker Cc: linux-sparse@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-hardening@vger.kernel.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, Vincent Mailhol X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=1089; i=mailhol.vincent@wanadoo.fr; h=from:subject:message-id; bh=MUJOQQOOJL9dYDVaPT65KhZRSmD+ZVJ1pjvxSAixArY=; b=owGbwMvMwCV2McXO4Xp97WbG02pJDOm+74/KH7/U7qegXjXTofXb3TYljXrmuVYbMjW/tLXe4 w0P49vQUcrCIMbFICumyLKsnJNboaPQO+zQX0uYOaxMIEMYuDgFYCKiExj+h59n32w4XUS9Q6Hd rUTL9LrKv/cufhltT6M9vi38WfriOSPDth1s9Y4XTgudV69oFplrmhzR2RRm0jljjlHtl08TxWX ZAQ== X-Developer-Key: i=mailhol.vincent@wanadoo.fr; a=openpgp; fpr=ED8F700574E67F20E574E8E2AB5FEB886DBB99C2 X-Endpoint-Received: by B4 Relay for mailhol.vincent@wanadoo.fr/default with auth_id=291 X-Original-From: Vincent Mailhol Reply-To: mailhol.vincent@wanadoo.fr From: Vincent Mailhol For completion, add statically_false() which is the equivalent of statically_true() except that it will return true only if the input is known to be false at compile time. The == operator is used instead of the ! negation to prevent a -Wint-in-bool-context compiler warning when the argument is not a boolean. For example: statically_false(var * 0) Signed-off-by: Vincent Mailhol --- include/linux/compiler.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 469a64dd6495fefab2c85ffc279568a657b72660..a2a56a50dd85227a4fdc62236a2710ca37c5ba52 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -314,6 +314,7 @@ static inline void *offset_to_ptr(const int *off) * values to determine that the condition is statically true. */ #define statically_true(x) (__builtin_constant_p(x) && (x)) +#define statically_false(x) (__builtin_constant_p(x) && (x) == 0) /* * This is needed in functions which generate the stack canary, see