From patchwork Mon Nov 12 11:57:13 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Thierry X-Patchwork-Id: 10678575 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 85B1A14E2 for ; Mon, 12 Nov 2018 12:05:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 72C642857F for ; Mon, 12 Nov 2018 12:05:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 65EFB29084; Mon, 12 Nov 2018 12:05:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.6 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 0AE752857F for ; Mon, 12 Nov 2018 12:05:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=0EWzi3IkZOJx7iDV4YsJjHNdkhBjzXEWXkXcSkq1IjY=; b=rm1aIqKEbWinJg5npbW2Q8nzzS HZDNIG2940VPfDctxjCwXss67WSWBbsKfuk0t2j5D/VBceYeIwG/MwbxZQybu8VGqh6U2apO0TW77 p6p15FqAfyN2aCA3P7udlO+BbuxyWqZePXIfuvcaFUmmLlgPghApRap8NUSFFDq5GV+9aNgY7SNeQ nb3pn/cflP7KrUUDuikSxYgCSbYhstOAlZlUPopeDccBu13o39HA3oWL3HBBiDj1lQciQ0o0cwz12 MOEL7S4tgcpzieUUgddHJBtxngRBPTtiLJbiI+IUfHRASnwbHCf3c/Nd0yHEylfBwm6KmH/RZJehh rnJpvQxw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gMAxX-0003aF-IX; Mon, 12 Nov 2018 12:04:51 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gMArL-00050C-N4 for linux-arm-kernel@bombadil.infradead.org; Mon, 12 Nov 2018 11:58:27 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=References:In-Reply-To:Message-Id:Date: Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=fVPpcgyWnXP69qJMQnEmahgKA6Hyr+ekOGnWYJKHvhQ=; b=VWcMshKhB0e5Je+QZNLm5z2WJ Ol1QtWsaeIAOV8c9CrXSl1mEG/JhenV0UBwCvX1hbjND6ZtR9NPT/ZxccAqdtr7NYMP3FSaCZ5StY 5ysq5Tk65W2xncH8cdkSjFKL1XPsZDr0xjCfYHtmwwfatVhLcNjtzZyTZD6CyikYBsXlRzXWVu74M JKjBRcpPB/K5UZh6EOdByFPnhQQmy7gAYRXwQMnITuZxcgog/69kWKbvlY9QdfJfH3/FLOrqqTrQ2 g+wTZYTZxY3B9vecx3QoBK4G0l/GERPI5NXqVkDfRVTqzKLuJ/0hKqTHlNXi/tOakGcPOpGZoONaM fMDwGEsKQ==; Received: from foss.arm.com ([217.140.101.70]) by casper.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gMArI-0003b8-JY for linux-arm-kernel@lists.infradead.org; Mon, 12 Nov 2018 11:58:26 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0205015BF; Mon, 12 Nov 2018 03:58:16 -0800 (PST) Received: from e112298-lin.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 363A83F5A0; Mon, 12 Nov 2018 03:58:14 -0800 (PST) From: Julien Thierry To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v6 22/24] arm64: Skip preemption when exiting an NMI Date: Mon, 12 Nov 2018 11:57:13 +0000 Message-Id: <1542023835-21446-23-git-send-email-julien.thierry@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1542023835-21446-1-git-send-email-julien.thierry@arm.com> References: <1542023835-21446-1-git-send-email-julien.thierry@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181112_115824_852983_174A58A6 X-CRM114-Status: UNSURE ( 9.74 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: daniel.thompson@linaro.org, Julien Thierry , marc.zyngier@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, christoffer.dall@arm.com, james.morse@arm.com, joel@joelfernandes.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Handling of an NMI should not set any TIF flags. For NMIs received from EL0 the current exit path is safe to use. However, an NMI received at EL1 could have interrupted some task context that has set the TIF_NEED_RESCHED flag. Preempting a task should not happen as a result of an NMI. Skip preemption after handling an NMI from EL1. Signed-off-by: Julien Thierry Cc: Catalin Marinas Cc: Will Deacon Cc: Marc Zyngier --- arch/arm64/kernel/entry.S | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index eb8120e..e02ee55 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -636,6 +636,14 @@ el1_irq: #ifdef CONFIG_PREEMPT ldr w24, [tsk, #TSK_TI_PREEMPT] // get preempt count +alternative_if ARM64_HAS_IRQ_PRIO_MASKING + /* + * DA_F were cleared at start of handling. If anything is set in DAIF, + * we come back from an NMI, so skip preemption + */ + mrs x0, daif + orr w24, w24, w0 +alternative_else_nop_endif cbnz w24, 1f // preempt count != 0 ldr x0, [tsk, #TSK_TI_FLAGS] // get flags tbz x0, #TIF_NEED_RESCHED, 1f // needs rescheduling?