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 EA7A4C433EF for ; Tue, 7 Jun 2022 19:32:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355854AbiFGTav (ORCPT ); Tue, 7 Jun 2022 15:30:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37522 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352305AbiFGSiV (ORCPT ); Tue, 7 Jun 2022 14:38:21 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F4B71842E8; Tue, 7 Jun 2022 10:58:14 -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 06133B82239; Tue, 7 Jun 2022 17:58:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3CB39C34119; Tue, 7 Jun 2022 17:58:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654624690; bh=I2/Q9j+xDREdk8V1BM4fCkekGaFWomnYTF/1/GKomvc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=StKiAmvh0sDmsXqebHqyoe0KKhWxPz6W+M+cETCxiK9ZagLsBV1wP3N6t1l/7rhR9 45Qg0YrcruMoeYbjjrHhEav5AhmyBA5OXMY2wxm4bQLXr7Y7me3ujmicvJzBwYgKhz vdq7l/DFXAAUQoUkofaH79M8mfWSXk4RF8gB42HaIR68/vtJ/IA4APe4I9JEFDAdJG CQ+dIS5sj8bOjvkQr0IrMuoDAl3uNbgrRP5hR0ytPDF+OGWhVgJ/wvq8O/7lKwWHfc DME+XZdUIZlVx2wxcTxCoZLIAdgeAXQCrmDJ+2OgdtSifDz3+1VNfYwlq7fkhHc3XS 5VZF1owva9Rbw== 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 5.15 42/51] x86/cpu: Elide KCSAN for cpu_has() and friends Date: Tue, 7 Jun 2022 13:55:41 -0400 Message-Id: <20220607175552.479948-42-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220607175552.479948-1-sashal@kernel.org> References: <20220607175552.479948-1-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 16a51e7288d5..b0f206681fde 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