From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 759C0C43334 for ; Tue, 7 Jun 2022 18:49:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346384AbiFGSt3 (ORCPT ); Tue, 7 Jun 2022 14:49:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352595AbiFGSRV (ORCPT ); Tue, 7 Jun 2022 14:17:21 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7906E13A2CA; Tue, 7 Jun 2022 10:52:25 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 307AC617AA; Tue, 7 Jun 2022 17:52:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35748C34115; Tue, 7 Jun 2022 17:52:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654624343; bh=QNxyg8a/EeMSToOh3j6ZgqqKkIM/59Fix+XBI1emb1w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IvzUvjr46HVsVFEtOIPpBDPMenYncLCA8TQHAMojzxyr2LXj53OJZzIHyUWT6UtQj 3+e1hDO4HT8ddkgQNd6kRWp3SVA8TurAOGW3gx6eSsbWXpflUG6fdAXA359Ci/GlFO 9b/FU6FT6nYA7SWrXNzd9h3CvgLBKz2KyF2XtrZyY4tDoiEw2cedaPE7oPqPXjkHNg 72v2Rv8fPjqXYcL6qp+1bpZqfqtM/XSLF4HT303bt1RA+OuZNFC8XLap413olh3rde P03E8OUzVHkCed31uU10QGtI/ZmjGl3H/rzQvIRQZtjwLYGj2w1P0FUt9VlPGGjxoH A2M0kvGDMd92A== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Peter Zijlstra , kernel test robot , Sasha Levin , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, keescook@chromium.org Subject: [PATCH AUTOSEL 5.18 54/68] x86/cpu: Elide KCSAN for cpu_has() and friends Date: Tue, 7 Jun 2022 13:48:20 -0400 Message-Id: <20220607174846.477972-54-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220607174846.477972-1-sashal@kernel.org> References: <20220607174846.477972-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra [ Upstream commit a6a5eb269f6f3a2fe392f725a8d9052190c731e2 ] As x86 uses the headers, the regular forms of all bitops are instrumented with explicit calls to KASAN and KCSAN checks. As these are explicit calls, these are not suppressed by the noinstr function attribute. This can result in calls to those check functions in noinstr code, which objtool warns about: vmlinux.o: warning: objtool: enter_from_user_mode+0x24: call to __kcsan_check_access() leaves .noinstr.text section vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x28: call to __kcsan_check_access() leaves .noinstr.text section vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x24: call to __kcsan_check_access() leaves .noinstr.text section vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x24: call to __kcsan_check_access() leaves .noinstr.text section Prevent this by using the arch_*() bitops, which are the underlying bitops without explciit instrumentation. [null: Changelog] Reported-by: kernel test robot Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220502111216.290518605@infradead.org Signed-off-by: Sasha Levin --- arch/x86/include/asm/cpufeature.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 1261842d006c..49a3b122279e 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -51,7 +51,7 @@ extern const char * const x86_power_flags[32]; extern const char * const x86_bug_flags[NBUGINTS*32]; #define test_cpu_cap(c, bit) \ - test_bit(bit, (unsigned long *)((c)->x86_capability)) + arch_test_bit(bit, (unsigned long *)((c)->x86_capability)) /* * There are 32 bits/features in each mask word. The high bits -- 2.35.1