From patchwork Tue Mar 28 16:49:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 13191368 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id E1EE1C6FD18 for ; Tue, 28 Mar 2023 16:50:07 +0000 (UTC) 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:Subject:From:Cc:To:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=0ShTpSvXs5xoOGE3YSps9Liz0FMTpNe7AasQGFsaTjA=; b=XiuDxMAvZbV8z/ OB09grGqjfXNPmycP8cGTID+ceBw+fVY2OaNxdk1iNV+RkhK9QbLqtooHXdtI55cd8RTtd3K/idIe 6T3rGN21zuX1w8vIlvxvlyd9gwLk5NcXuM61D6mlnwv95NKPZrk7pw+xjRLbbY8eVPujMb9ZQgNsZ TWcVFaQnWDgE/Ug0hm4aok7bKyxzqtlIv6Og3OcPy5WBHuI7p8idm+P/QHVO+rUifLWzuRVUpO1Pk tC/vatRckN/PpyKvWiUrVgo6zFehDbb8In0Yq+9HOQG8PlIwzvLIWd3QXtE/9y2Uc01o1ppJFQOZO lBEKnterNuoA/fnKMLWw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1phCVb-00FBou-0e; Tue, 28 Mar 2023 16:49:19 +0000 Received: from mail-il1-x12e.google.com ([2607:f8b0:4864:20::12e]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1phCVO-00FBgx-2q for linux-arm-kernel@lists.infradead.org; Tue, 28 Mar 2023 16:49:08 +0000 Received: by mail-il1-x12e.google.com with SMTP id h11so6631398ild.11 for ; Tue, 28 Mar 2023 09:49:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; t=1680022144; x=1682614144; h=content-transfer-encoding:subject:from:cc:to:content-language :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=q162jzgroWyRXHqIPK7jRPB2m7mh8g3iIrSKRUquz1E=; b=mn2ia4vi1FwV9L6GXtmRn9T940URdsR1MEd9LmAqbgIx6D3XYVeP+9Z7IkhVC4LDsE ZojOsxUJ+8ech+W8i6ZKAhzvzbTf5/fnI5iZ2a/s/JBGnOYCLEewCdYAboRxd0moMtws 5mQf1E7o1n0Kxi3FaTbjHyUeViimsSALryDfnsw/+PmKr28GDEZQ+BgDXp8iUu5d3x0M NVBLktvu3+q6LBGv3k6PAlVCsfs2Fz6SLEB7R7Vl3mnLQgkWF8mcjNXtxDZbDPhuXwl0 Po3ArXIVjXKx47+h/6L0vj3Z/ot70hY219TWxYS9etyhw+KQH+ronslv8nENYrtcrtIa nGxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680022144; x=1682614144; h=content-transfer-encoding:subject:from:cc:to:content-language :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=q162jzgroWyRXHqIPK7jRPB2m7mh8g3iIrSKRUquz1E=; b=KDoUuXiV9doRBaNIqUMan2Ac3UPA3mzprgCZPygYD1aNzV6kChNgndJJnlAbNXWZA7 /fI7LHJlJm0QX2D+FEg+8Qoa9O7P82qlvXw7c9uhOLTSPBHxD9mTQtTdNon4GJcTTXPT 7qAkSt9v0ibqtUxSPwWUAQhlkEmIIs7Krl/GmKmvEAl7ROTQLFs7BLJ3yv6fnr2nZ+VI zvAWeO7wv7sNZ5ppbQhERiINAJvA0WjCHR0JUPYvxwdQT9i1iAL19ztyDhaqsfC8iM9Y kC/67/nlEN2U1a2d/TVXY8KrMqjZAsq6ayhlRbcvVktKn7XKLs00sBMX8cMEqXFrN19N j4TQ== X-Gm-Message-State: AAQBX9eFk8Ah1mJN44F7zwpQG2aE35xkM/cYtTslbi+2hlLbl325gSLt qr2yXGpUGCj9Lmgh1uvgM/Jicvf8DXqaqGdplrwmMg== X-Google-Smtp-Source: AKy350awiOQsXaewh5W7+8Pz8PfE/JqBYA2w4QwOdUaJb0LiHZ42vpmjXQeg0gDPExkHN4IHjOTrHA== X-Received: by 2002:a05:6e02:88c:b0:325:c88b:79b6 with SMTP id z12-20020a056e02088c00b00325c88b79b6mr8777079ils.2.1680022144126; Tue, 28 Mar 2023 09:49:04 -0700 (PDT) Received: from [192.168.1.94] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id k20-20020a928e54000000b00325eddf4dc4sm2546122ilh.3.2023.03.28.09.49.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 28 Mar 2023 09:49:03 -0700 (PDT) Message-ID: Date: Tue, 28 Mar 2023 10:49:03 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Content-Language: en-US To: linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas , Will Deacon From: Jens Axboe Subject: [PATCH v2] arm64: treat PF_IO_WORKER like PF_KTHREAD for mitigations X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230328_094906_920877_78DD1CA2 X-CRM114-Status: GOOD ( 10.84 ) 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 Like PF_KTHREAD, PF_IO_WORKER never exit to userspace. They exist entirely within the kernel, and hence don't need any task mitigations applied. Signed-off-by: Jens Axboe --- v2: include ssbs_thread_switch() too diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 71d59b5abede..9ce614b2177e 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -445,9 +445,11 @@ static void ssbs_thread_switch(struct task_struct *next) { /* * Nothing to do for kernel threads, but 'regs' may be junk - * (e.g. idle task) so check the flags and bail early. + * (e.g. idle task) so check the flags and bail early. Nothing to do + * for IO worker threads either, as they never transition between + * kernel and userspace. */ - if (unlikely(next->flags & PF_KTHREAD)) + if (unlikely(next->flags & (PF_KTHREAD | PF_IO_WORKER))) return; /* diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c index fca9cc6f5581..25a21c3d446c 100644 --- a/arch/arm64/kernel/proton-pack.c +++ b/arch/arm64/kernel/proton-pack.c @@ -654,7 +654,7 @@ static void __update_pstate_ssbs(struct pt_regs *regs, bool state) void spectre_v4_enable_task_mitigation(struct task_struct *tsk) { struct pt_regs *regs = task_pt_regs(tsk); - bool ssbs = false, kthread = tsk->flags & PF_KTHREAD; + bool ssbs = false, kthread = tsk->flags & (PF_KTHREAD | PF_IO_WORKER); if (spectre_v4_mitigations_off()) ssbs = true;