From mboxrd@z Thu Jan 1 00:00:00 1970 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 81EB5C433B4 for ; Tue, 18 May 2021 09:47:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AAF5613CB for ; Tue, 18 May 2021 09:47:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348061AbhERJtN (ORCPT ); Tue, 18 May 2021 05:49:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:49726 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348039AbhERJtJ (ORCPT ); Tue, 18 May 2021 05:49:09 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E073B61396; Tue, 18 May 2021 09:47:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621331272; bh=RTAwS1Pb2T4YH9RTWzE3GXmCSLarrFRCCZxfeC0IjGo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GWOXp+zS1a58Dta3KChjDG5CJSAxD2/cHljq4pP1pAYtJd7zAhjfF9NQE9x23csXy N8MBfE/duY99QsBbvPB2PlmyTVMH0XJI57ErJ0MU+EzCWNTRbdbBbqGp8HTT64W1LL gYdiyfNbLozlC37iqdcQtttiQpriKoprIdRxSFlKaVoLc35LortpU/SKFa2vno1R4V +bI1Jv4qPJlwXn8SRZXTKI6Z8NkGgcT3UDV1BatVuWJOE0FrVwH0DaHmISPQVg3pHy xoApFmXHckl+UbvFmk5RMZhI9EIzE+KyTrPOY6Va37bK3ZKU42ebAtliYmWsgwtIRl pOzJM3y2TiX0w== 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 04/21] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Date: Tue, 18 May 2021 10:47:08 +0100 Message-Id: <20210518094725.7701-5-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 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Scheduling a 32-bit application on a 64-bit-only CPU is a bad idea. Ensure that 32-bit applications always take the slow-path when returning to userspace on a system with mismatched support at EL0, so that we can avoid trying to run on a 64-bit-only CPU and force a SIGKILL instead. Signed-off-by: Will Deacon --- arch/arm64/kernel/process.c | 19 ++++++++++++++++++- arch/arm64/kernel/signal.c | 26 ++++++++++++++++++++++++++ 2 files changed, 44 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index b4bb67f17a2c..f4a91bf1ce0c 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -527,6 +527,15 @@ 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) { /* @@ -568,6 +577,7 @@ __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 @@ -633,8 +643,15 @@ unsigned long arch_align_stack(unsigned long sp) */ void arch_setup_new_exec(void) { - current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; + unsigned long mmflags = 0; + + if (is_compat_task()) { + mmflags = MMCF_AARCH32; + if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) + set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); + } + current->mm->context.flags = mmflags; ptrauth_thread_init_user(); mte_thread_init_user(); diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 6237486ff6bb..f8192f4ae0b8 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -911,6 +911,19 @@ 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) { @@ -938,6 +951,19 @@ 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) -- 2.31.1.751.gd2f1c929bd-goog From mboxrd@z Thu Jan 1 00:00:00 1970 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 6AC9DC433ED for ; Tue, 18 May 2021 09:54:48 +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 00DD0610A1 for ; Tue, 18 May 2021 09:54:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 00DD0610A1 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=VrpcspceiMMEPL6Cjtj8vPK7m7Yrm/PPDlaruPvlyJ4=; b=nHiazr2ucZEnGU4Mi89TbYSXo 75IakMyaTRWsOak++5wurRMudUQ75VW/tZqk4a//ypJQbz6Qcdrs4092fZ+qPNyVI7Y5VhuAwXUEp ZatwN+ctErgMAxvPV33plxAjuirw7fBQqrc+5bAg1TMmhbfYcEYRuw+GKchYCaaypGB+jxtC5qFm9 fVsBDJpwGBCG0RKtrJtvqzy8pu/1OSRefecBULEBl2TKi8iq5njcVbT73NWyIujd4Ldj5fmcNLix4 sr1lNYW7kE8kppHQgtGFDZtCwkM67kFOuqT0gNJYV9UMp0asXqc0PnsCM+RvLYPQO8+wvAHt7E1H9 u97tcRJiw==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1liwP3-000EvR-Co; Tue, 18 May 2021 09:52:42 +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 1liwKR-000Doy-M3 for linux-arm-kernel@desiato.infradead.org; Tue, 18 May 2021 09:47:55 +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=H+gluzK/c87K8IKp3ObwtqZ2D5iBrtAAx4x/MZ/PQPw=; b=g3vcUR1gSxFuxhM/Fido6rL9B4 hgy7X1MA0ZRnPgGappQKWSehORa+pVPP2FqIu89WJxFXsOIXffBnJPsG2K8e76ajGbS2UqbxwpJVl 33DpL64qlFx4HKqYxH4bXzxj8oDs4TAMowW9m/DIKjEJR0iAW/3bWh5B7If0/39Y0Ubwjw17VIwgt 5sRgB5gAcX3hrFCLJEtElPuvAy09ES6hq+mNztfiJc+x4cgckOBMohZur711EIOnWX18GAPuhC+rH L+Rsmp2EuCt6ALxj4dTx7S/Epydm+NCYkYY0JdI3ujxfmNMZ2hFoZw5ODJWyaWNCkVUxHE49kuLm4 0BGtew9A==; Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1liwKO-00EWcY-B6 for linux-arm-kernel@lists.infradead.org; Tue, 18 May 2021 09:47:54 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id E073B61396; Tue, 18 May 2021 09:47:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621331272; bh=RTAwS1Pb2T4YH9RTWzE3GXmCSLarrFRCCZxfeC0IjGo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GWOXp+zS1a58Dta3KChjDG5CJSAxD2/cHljq4pP1pAYtJd7zAhjfF9NQE9x23csXy N8MBfE/duY99QsBbvPB2PlmyTVMH0XJI57ErJ0MU+EzCWNTRbdbBbqGp8HTT64W1LL gYdiyfNbLozlC37iqdcQtttiQpriKoprIdRxSFlKaVoLc35LortpU/SKFa2vno1R4V +bI1Jv4qPJlwXn8SRZXTKI6Z8NkGgcT3UDV1BatVuWJOE0FrVwH0DaHmISPQVg3pHy xoApFmXHckl+UbvFmk5RMZhI9EIzE+KyTrPOY6Va37bK3ZKU42ebAtliYmWsgwtIRl pOzJM3y2TiX0w== 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 04/21] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Date: Tue, 18 May 2021 10:47:08 +0100 Message-Id: <20210518094725.7701-5-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_024752_444883_091B4ADD X-CRM114-Status: GOOD ( 17.40 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Scheduling a 32-bit application on a 64-bit-only CPU is a bad idea. Ensure that 32-bit applications always take the slow-path when returning to userspace on a system with mismatched support at EL0, so that we can avoid trying to run on a 64-bit-only CPU and force a SIGKILL instead. Signed-off-by: Will Deacon --- arch/arm64/kernel/process.c | 19 ++++++++++++++++++- arch/arm64/kernel/signal.c | 26 ++++++++++++++++++++++++++ 2 files changed, 44 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index b4bb67f17a2c..f4a91bf1ce0c 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -527,6 +527,15 @@ 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) { /* @@ -568,6 +577,7 @@ __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 @@ -633,8 +643,15 @@ unsigned long arch_align_stack(unsigned long sp) */ void arch_setup_new_exec(void) { - current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; + unsigned long mmflags = 0; + + if (is_compat_task()) { + mmflags = MMCF_AARCH32; + if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) + set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); + } + current->mm->context.flags = mmflags; ptrauth_thread_init_user(); mte_thread_init_user(); diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 6237486ff6bb..f8192f4ae0b8 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -911,6 +911,19 @@ 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) { @@ -938,6 +951,19 @@ 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) -- 2.31.1.751.gd2f1c929bd-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel