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 X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D852DC5CFEB for ; Tue, 10 Jul 2018 02:21:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7C77D208A2 for ; Tue, 10 Jul 2018 02:21:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="kZeCaym6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C77D208A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933112AbeGJCV4 (ORCPT ); Mon, 9 Jul 2018 22:21:56 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:39577 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932824AbeGJCVu (ORCPT ); Mon, 9 Jul 2018 22:21:50 -0400 Received: by mail-pf0-f193.google.com with SMTP id s21-v6so14997344pfm.6 for ; Mon, 09 Jul 2018 19:21:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=vDKwRhBT3xRWEawJSRgrGiYt4RPW/JhbX7FaiHY8aIw=; b=kZeCaym6SRHjpAsekCH79GJNC24Q9erSL9P+hGDiFAGB3JRNdoJMrAJPotfgowSQYY jajY4d2YMAy3c0/LaIvswbiGSfhdq0m6bysmcF49yqWhsd0IwrF1GYYTZTXz5mokM8kG 0cwvVhjB1W7Ylv2T7yQ6o79Q6Q10ukk9iZwFST+xNeWywN9i2oZSI+hsU3+jtxukju5l 8l+3j5lc0GxZlxdZ7Vf0RW7ZLohL4S3T0EDxh4Dovmc2lHOEr8wEHRmMQ2mb4FCPPPeR rEs5vG0kvNSUh6hPOvHpY/dOelcBG4Q0PmuZ17mj2vNHuGVFXWTHIpScAiwOOcxTRBNC ULkw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=vDKwRhBT3xRWEawJSRgrGiYt4RPW/JhbX7FaiHY8aIw=; b=a4vyo4YfMtih3LxdCsg8goBgPP42MtFOdHpfP68EcI+kcwZVcuN07IVvyTFI/UcMlX RwvRzewJjZkbcH23mM9LMTmtBTfej2/wxbR6eCKZG2tCzS65Rau2fEit3YM5FvJq7qx5 yC+rRWmOxrd+/F16+Re39ItwCDaHM9PEH3rDw8DsBsVrrJb5oV4IO2KtpKheRhQJGffP kcB2NBcmmufb4wlBjirX6OHk8+XBIpFwQuQ6x8suUbyKgb7+iZxyV7RK/kkEPRCuSCjO PtK47QDyGjdLNBexszweLBqodambSFwAJioiKf1w2MNYva+mfqmRvwOAO+ya8nZV45qS P7Vg== X-Gm-Message-State: APt69E0WI143FTCybvCpyqnd1HXYCfNommoJwStM2znXUKeQQlEm+8Sl 59zyHdUg9tX8WtpOUaocXNY= X-Google-Smtp-Source: AAOMgpdSM5yfvTnzqD0Joitp3/svAjmD5nxmuFc6rE292NBfSzY12Da9A9m7vKPtKYw/XGQUNR0jkA== X-Received: by 2002:a62:384:: with SMTP id 126-v6mr6271152pfd.11.1531189309736; Mon, 09 Jul 2018 19:21:49 -0700 (PDT) Received: from bj03003pcul8.spreadtrum.com ([117.18.48.82]) by smtp.gmail.com with ESMTPSA id x28-v6sm26331105pfk.55.2018.07.09.19.21.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 09 Jul 2018 19:21:49 -0700 (PDT) From: "Yandong.Zhao" To: Dave.Martin@arm.com Cc: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, ard.biesheuvel@linaro.org, linux-kernel@vger.kernel.org, zhaoyd@thundersoft.com, zhaoxb@thundersoft.com, fanlc0801@thundersoft.com, Yandong Zhao Subject: [PATCH] arm64: neon: Fix function may_use_simd() return error status Date: Tue, 10 Jul 2018 10:21:40 +0800 Message-Id: <1531189300-26216-1-git-send-email-yandong77520@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Yandong Zhao Operations for contexts where we do not want to do any checks for preemptions. Unless strictly necessary, always use this_cpu_read() instead. Because of the kernel_neon_busy here we have to make sure that it is the current cpu. Signed-off-by: Yandong Zhao --- arch/arm64/include/asm/simd.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/simd.h b/arch/arm64/include/asm/simd.h index fa8b3fe..8b97f8b 100644 --- a/arch/arm64/include/asm/simd.h +++ b/arch/arm64/include/asm/simd.h @@ -29,7 +29,8 @@ static __must_check inline bool may_use_simd(void) { /* - * The raw_cpu_read() is racy if called with preemption enabled. + * The this_cpu_read() is racy if called with preemption enabled, + * since the task my subsequently migrate to another CPU. * This is not a bug: kernel_neon_busy is only set when * preemption is disabled, so we cannot migrate to another CPU * while it is set, nor can we migrate to a CPU where it is set. @@ -42,7 +43,7 @@ static __must_check inline bool may_use_simd(void) * false. */ return !in_irq() && !irqs_disabled() && !in_nmi() && - !raw_cpu_read(kernel_neon_busy); + !this_cpu_read(kernel_neon_busy); } #else /* ! CONFIG_KERNEL_MODE_NEON */ -- 1.9.1