From patchwork Tue May 18 09:47:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 12264483 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,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 86D90C433B4 for ; Tue, 18 May 2021 10:11:42 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 1923A60BD3 for ; Tue, 18 May 2021 10:11:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1923A60BD3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; 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=gy56GjVXMKHSj/aTt6kVn9gQM25jTQDStUeUQcTbOXU=; b=ZOo3jvIuvOFG48jzs+BNUzwG+ cNFypkooIE3+OJRS4poV7GNZnpKvE59/JHr70GhlPOTqSFfDNITQ8E3UObnwzhmnh2WI+eEA2bUy/ xJ+1ciQ8XxAhwH8RCZq2SboWWdpuX1/w6qmirfOoL+ZYQAo67pllgh09iCiqwkQ8HnBDksqydJDuE RHvTI5WkR64e8QCe9lljZ41OMLCymGWwAN3I6yUHoXOVv60tEoTi+muQ6QU5RfWLBvovxBohmVX+W h5+aNY6XvlmjoaEUa5k4o37qN89mxtB565w5zZ0fSCDmfc7ifHRTmTmrWbaLGstTps4BT/bhC9++g 3Q+tO9MTQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1liwfQ-000HxN-Gb; Tue, 18 May 2021 10:09:36 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1liwLM-000E4W-26 for linux-arm-kernel@desiato.infradead.org; Tue, 18 May 2021 09:48:52 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=IPBAwtBdNfOl2ou4HntULZzpESobs8OaXnbxndEUnHM=; b=kh98XLPBiNmQxxNuRAi4t6dw8d YyCOxCDb7l6kj64skFWDB2mhbmVvgCNBt1V4FMCDZOPjT4m1bPDHgX/LZyfiYWs4FoODkJFHTl7cg F16RM2A0mIvYWev9tHQ0HE/Qu7hH5AIJmHrX6jIrl5tVdyVtiNNPnKnJyHUFjekxaMHH5okx6riyL Bz3M4630/dkkIK/+SGS035jNvQWIaHS3KFS0hQYJwCmIX381vrWYgMOtZmBm5dI+fpWM6py1Ecu0z p9efThvKn6kBC2Ma2Gb3P3/y2WXk2CRPWWAYVBx5DtiW+kC0sPtZmDomG/ei1TZuuV56Ycbl2thR6 tQemnI/w==; Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1liwLJ-00EWoW-CP for linux-arm-kernel@lists.infradead.org; Tue, 18 May 2021 09:48:50 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id D7446613EB; Tue, 18 May 2021 09:48:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621331329; bh=cxh0O3aWsznuhosSjWq+pFkb/mSjtZzHnDThwdnjZQg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GoWEGGqCZBOkoC2+SS/nheiXu/2Hmo+WC9UVd5Z+j0CNnv8h4OqnLXGjaGl7iNbry ShR1l32aTvoPswFIknrj2CogVOF2bOIy8UbnShkpro4zTF4Mdp8mHB6mLZ7YqKw2Sq w9LRuhE9hHajS9IrAYzQaanN21jDJo3euMA8ZbUGi9rgadI90kZ6lo4/KMWo8q/dQb Ebq0jOV4AnXerbs0ME7zLpmBDWxOotDxU+HPHaiQOld41NDrnWWqNmic55rsFPGAm+ J7pigE6MSeZTmxNgfxbMfZiMdMfYw1D7Py2GuJm8bLRwvsECD0VSpBEn9LwhvuqBfk 0FAbg8A9ApvZA== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Will Deacon , Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , Quentin Perret , Tejun Heo , Li Zefan , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , "Rafael J. Wysocki" , kernel-team@android.com Subject: [PATCH v6 20/21] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Date: Tue, 18 May 2021 10:47:24 +0100 Message-Id: <20210518094725.7701-21-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210518094725.7701-1-will@kernel.org> References: <20210518094725.7701-1-will@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210518_024849_482757_0E3DAECC X-CRM114-Status: GOOD ( 14.88 ) 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 The scheduler now knows enough about these braindead systems to place 32-bit tasks accordingly, so throw out the safety checks and allow the ret-to-user path to avoid do_notify_resume() if there is nothing to do. Signed-off-by: Will Deacon Acked-by: Catalin Marinas --- arch/arm64/kernel/process.c | 14 +------------- arch/arm64/kernel/signal.c | 26 -------------------------- 2 files changed, 1 insertion(+), 39 deletions(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 8e0da06c4e77..de9833f08742 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -527,15 +527,6 @@ static void erratum_1418040_thread_switch(struct task_struct *prev, write_sysreg(val, cntkctl_el1); } -static void compat_thread_switch(struct task_struct *next) -{ - if (!is_compat_thread(task_thread_info(next))) - return; - - if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) - set_tsk_thread_flag(next, TIF_NOTIFY_RESUME); -} - static void update_sctlr_el1(u64 sctlr) { /* @@ -577,7 +568,6 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, ssbs_thread_switch(next); erratum_1418040_thread_switch(prev, next); ptrauth_thread_switch_user(next); - compat_thread_switch(next); /* * Complete any pending TLB or cache maintenance on this CPU in case @@ -657,10 +647,8 @@ void arch_setup_new_exec(void) * at the point of execve(), although we try a bit harder to * honour the cpuset hierarchy. */ - if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) { + if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) force_compatible_cpus_allowed_ptr(current); - set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); - } } else if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) { relax_compatible_cpus_allowed_ptr(current); } diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index f8192f4ae0b8..6237486ff6bb 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -911,19 +911,6 @@ static void do_signal(struct pt_regs *regs) restore_saved_sigmask(); } -static bool cpu_affinity_invalid(struct pt_regs *regs) -{ - if (!compat_user_mode(regs)) - return false; - - /* - * We're preemptible, but a reschedule will cause us to check the - * affinity again. - */ - return !cpumask_test_cpu(raw_smp_processor_id(), - system_32bit_el0_cpumask()); -} - asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags) { @@ -951,19 +938,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, if (thread_flags & _TIF_NOTIFY_RESUME) { tracehook_notify_resume(regs); rseq_handle_notify_resume(NULL, regs); - - /* - * If we reschedule after checking the affinity - * then we must ensure that TIF_NOTIFY_RESUME - * is set so that we check the affinity again. - * Since tracehook_notify_resume() clears the - * flag, ensure that the compiler doesn't move - * it after the affinity check. - */ - barrier(); - - if (cpu_affinity_invalid(regs)) - force_sig(SIGKILL); } if (thread_flags & _TIF_FOREIGN_FPSTATE)