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 C2319CCA486 for ; Tue, 7 Jun 2022 19:42:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357000AbiFGTkr (ORCPT ); Tue, 7 Jun 2022 15:40:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354466AbiFGSrD (ORCPT ); Tue, 7 Jun 2022 14:47:03 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 882814C78A; Tue, 7 Jun 2022 11:01:23 -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 ams.source.kernel.org (Postfix) with ESMTPS id 4BA6AB82182; Tue, 7 Jun 2022 18:01:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4C4DC3411C; Tue, 7 Jun 2022 18:01:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654624881; bh=ZxmjvAyRXC2LFYdT7yWmSVT58DifZY7x0GFuK+Fi3t4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bv18WWslisUC+cKWyjXyFcZnolmQBBx7YzWwXD7EmCKTAFuY3snxt74EPXnaEG7Dt CVbNLoJIKnDXDfzxXQkIUO3UON3mYYk4TzQ3ecl4pyjmeV05Au1qRo1ZX+PmVQW14C qsKc9heG4nCi1/w+Af070Xmdvnx6a2PUFRD7fuuDV4AeGGYE9ZoqBjwq+t2q/vgbct 1M8i6WjeZqdjqGI0Hw/R1Z1hk+XdlBDHwpY8R+lWWhfLaVe9wDDspSAVapOb9yNqBV 9yl0vi0sBQcwfkQqCEHY+2ckDMdRHQ6O5bMHszbS5bexybF2K1IEVQPLRGHQvlnpdW yT4xX2+EB+I9Q== 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, keescook@chromium.org, hpa@zytor.com Subject: [PATCH AUTOSEL 5.4 28/34] x86/cpu: Elide KCSAN for cpu_has() and friends Date: Tue, 7 Jun 2022 14:00:03 -0400 Message-Id: <20220607180011.481266-28-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220607180011.481266-1-sashal@kernel.org> References: <20220607180011.481266-1-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 59bf91c57aa8..619c1f80a2ab 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -49,7 +49,7 @@ 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