From patchwork Wed Aug 11 20:13:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Valentin Schneider X-Patchwork-Id: 12431891 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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 53578C4338F for ; Wed, 11 Aug 2021 20:17:49 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EAAEE6101E for ; Wed, 11 Aug 2021 20:17:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org EAAEE6101E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=nTipj7af2k6OUxjZ87Ch9L9+YrMHNsC8OTOIMNjg5d0=; b=qQIA+lWUYxRcNe C8YJFh3bRKOGzGNshkKzWXP6ZvhcchDl9SGNOHCoTJ8OUnOE6IOhI4LewzGCTEonx2o8hIHpE3zT/ R4aAFMnCj1KKz7hXrbTWx6ZidYQQvX1TfBBVhhZNVWr9NrC/2ahKMzII2831xByfCoS1zVD6qmTtz 2asF9BN7qNpMbQoAWSC1R4Nq3FooVAaYQSbZA3eG5D87bhKze6KtwG3MTkrRrJFuRNA4mFY63A8Fs n/p7/OqdP8+OBjGEqmP+bZ3yZxCj7sW1+gcrrAUJByad3zwnPz/8Cr+g/diGBDOM7Z1R/DKKHO/4+ ffHyiPg7E+PaKhD7dvPw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mDud6-0082J1-QO; Wed, 11 Aug 2021 20:15:12 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mDucL-00822U-9K for linux-arm-kernel@lists.infradead.org; Wed, 11 Aug 2021 20:14:27 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3B867139F; Wed, 11 Aug 2021 13:14:24 -0700 (PDT) Received: from e113632-lin.cambridge.arm.com (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 219433F40C; Wed, 11 Aug 2021 13:14:21 -0700 (PDT) From: Valentin Schneider To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, rcu@vger.kernel.org, linux-rt-users@vger.kernel.org Cc: Catalin Marinas , Will Deacon , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Steven Rostedt , Daniel Bristot de Oliveira , Sebastian Andrzej Siewior , "Paul E. McKenney" , Frederic Weisbecker , Josh Triplett , Mathieu Desnoyers , Davidlohr Bueso , Lai Jiangshan , Joel Fernandes , Anshuman Khandual , Vincenzo Frascino , Steven Price , Ard Biesheuvel , Boqun Feng , Mike Galbraith Subject: [PATCH v3 4/4] arm64: mm: Make arch_faults_on_old_pte() check for migratability Date: Wed, 11 Aug 2021 21:13:54 +0100 Message-Id: <20210811201354.1976839-5-valentin.schneider@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210811201354.1976839-1-valentin.schneider@arm.com> References: <20210811201354.1976839-1-valentin.schneider@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210811_131425_423059_37D5D8EF X-CRM114-Status: GOOD ( 12.68 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org arch_faults_on_old_pte() relies on the calling context being non-preemptible. CONFIG_PREEMPT_RT turns the PTE lock into a sleepable spinlock, which doesn't disable preemption once acquired, triggering the warning in arch_faults_on_old_pte(). It does however disable migration, ensuring the task remains on the same CPU during the entirety of the critical section, making the read of cpu_has_hw_af() safe and stable. Make arch_faults_on_old_pte() check migratable() instead of preemptible(). Signed-off-by: Valentin Schneider --- arch/arm64/include/asm/pgtable.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index f09bf5c02891..8c0de3234b20 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -995,7 +995,7 @@ static inline void update_mmu_cache(struct vm_area_struct *vma, */ static inline bool arch_faults_on_old_pte(void) { - WARN_ON(preemptible()); + WARN_ON(migratable()); return !cpu_has_hw_af(); }