From patchwork Tue Jun 8 18:03:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 12307895 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=-17.2 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,URIBL_BLOCKED,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 C11B4C47082 for ; Tue, 8 Jun 2021 18:23:11 +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 8B98261376 for ; Tue, 8 Jun 2021 18:23:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8B98261376 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=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=bKm3ytQI/WiyZHEumhagJsYkmyL1656xu4urCPLXviI=; b=BYgeGC33PAPBPV 5NYW2TATl+zccNTjxAdU/QqVtMMt3eli5mz2ykjdJJwgS1DhmkjBUyuGb6PV2MDvkMLfu25eD/WsW OWc0Eibsx92SYOrKSRRmsm9jyDQCNOf5tCEcAkt9J4ICHV/EHLpgy8EJv9aILsmM4WKdGHg8i7zEZ FOoZXFWxLu2D2Ar3pzlmVl3gm7eD79hQ36SFTGebo1ZEH6skL9JHa9hfTRM9W3qJxrQNGvXWCTnHX yAllepsvHXi00G82TnagN6K55dojPmD/GAHwEgvqpsnqm+4v+oYxRQZKwwZxcsk+z2/c6tpwE67vL XMZcRBxgB6v+w72d9Cug==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqgLb-009xoE-3O; Tue, 08 Jun 2021 18:21:07 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqg5k-009rGL-RF for linux-arm-kernel@lists.infradead.org; Tue, 08 Jun 2021 18:04:46 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id F394961376; Tue, 8 Jun 2021 18:04:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623175484; bh=myX14SA0NbiCMTpW6ETGTKqEZ8H7i4uKBUWW7ZY/FWs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UgCipFwd3/Omvbu8g6SFRXU5rvWx1GsGfahJ1e6asrKhHOxo38bPTTAh8/XnvD8oD a5lhx0YJac9EOluHBi3kNOlonUk0+4rnOYjw9owI039qIlvhziPQUd4l5Npv+ErA1Y b16MhCG+Or20ZLM5HVngSrZnkqGMwhaZCT5avez99+CC/e1YskJGWzxgDMWDCGBIjl 10BdhdrNeQcIybJhPLNTmkryayOzjnGrxDt4LmqcZdn78i8VJi91gJ0XrRLWm6yEhr RAmMpEbv76uz+vGS7uLKJ7M/kdhghdY8OkJfjRqiX6qIzF9VYHDJjIazYiOBX1GbcK /b7DbG30PLoqA== 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 , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , "Rafael J. Wysocki" , Dietmar Eggemann , Daniel Bristot de Oliveira , Valentin Schneider , Mark Rutland , kernel-team@android.com Subject: [PATCH v9 19/20] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Date: Tue, 8 Jun 2021 19:03:12 +0100 Message-Id: <20210608180313.11502-20-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210608180313.11502-1-will@kernel.org> References: <20210608180313.11502-1-will@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210608_110444_975445_BA2F511B X-CRM114-Status: GOOD ( 14.94 ) 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. Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon --- 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 220134888d7e..1de4d934db7f 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -528,15 +528,6 @@ 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) { /* @@ -578,7 +569,6 @@ __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 @@ -680,10 +670,8 @@ 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)