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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham 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 ABC3FC3A5A2 for ; Fri, 23 Aug 2019 11:58:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8390222CE3 for ; Fri, 23 Aug 2019 11:58:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394342AbfHWL6f (ORCPT ); Fri, 23 Aug 2019 07:58:35 -0400 Received: from foss.arm.com ([217.140.110.172]:33058 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394137AbfHWL6c (ORCPT ); Fri, 23 Aug 2019 07:58:32 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 02E1B1570; Fri, 23 Aug 2019 04:58:32 -0700 (PDT) Received: from e120937-lin.cambridge.arm.com (e120937-lin.cambridge.arm.com [10.1.197.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6CFC13F246; Fri, 23 Aug 2019 04:58:30 -0700 (PDT) From: Cristian Marussi To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dave.martin@arm.com, james.morse@arm.com, mark.rutland@arm.com, catalin.marinas@arm.com, will@kernel.org, tglx@linutronix.de, peterz@infradead.org, takahiro.akashi@linaro.org, hidehiro.kawai.ez@hitachi.com Subject: [RFC PATCH 5/7] arm64: smp: use generic SMP stop common code Date: Fri, 23 Aug 2019 12:57:18 +0100 Message-Id: <20190823115720.605-6-cristian.marussi@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190823115720.605-1-cristian.marussi@arm.com> References: <20190823115720.605-1-cristian.marussi@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make arm64 use the generic SMP-stop logic provided by common code unified smp_send_stop() function. arm64 smp_send_stop() logic had a bug in it: it failed to consider the online status of the calling CPU when evaluating if any stop message needed to be sent to other CPus at all: this resulted, on a 2-CPUs system, in the failure to stop all cpus if one paniced while starting up, leaving such system in an unexpected lively state. [root@arch ~]# echo 1 > /sys/devices/system/cpu/cpu1/online [root@arch ~]# [ 152.583368] ------------[ cut here ]------------ [ 152.583872] kernel BUG at arch/arm64/kernel/cpufeature.c:852! [ 152.584693] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 152.585228] Modules linked in: [ 152.586040] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc5-00001-gcabd12118c4a-dirty #2 [ 152.586218] Hardware name: Foundation-v8A (DT) [ 152.586478] pstate: 000001c5 (nzcv dAIF -PAN -UAO) [ 152.587260] pc : has_cpuid_feature+0x35c/0x360 [ 152.587398] lr : verify_local_elf_hwcaps+0x6c/0xf0 [ 152.587520] sp : ffff0000118bbf60 [ 152.587605] x29: ffff0000118bbf60 x28: 0000000000000000 [ 152.587784] x27: 0000000000000000 x26: 0000000000000000 [ 152.587882] x25: ffff00001167a010 x24: ffff0000112f59f8 [ 152.587992] x23: 0000000000000000 x22: 0000000000000000 [ 152.588085] x21: ffff0000112ea018 x20: ffff000010fe5518 [ 152.588180] x19: ffff000010ba3f30 x18: 0000000000000036 [ 152.588285] x17: 0000000000000000 x16: 0000000000000000 [ 152.588380] x15: 0000000000000000 x14: ffff80087a821210 [ 152.588481] x13: 0000000000000000 x12: 0000000000000000 [ 152.588599] x11: 0000000000000080 x10: 00400032b5503510 [ 152.588709] x9 : 0000000000000000 x8 : ffff000010b93204 [ 152.588810] x7 : 00000000800001d8 x6 : 0000000000000005 [ 152.588910] x5 : 0000000000000000 x4 : 0000000000000000 [ 152.589021] x3 : 0000000000000000 x2 : 0000000000008000 [ 152.589121] x1 : 0000000000180480 x0 : 0000000000180480 [ 152.589379] Call trace: [ 152.589646] has_cpuid_feature+0x35c/0x360 [ 152.589763] verify_local_elf_hwcaps+0x6c/0xf0 [ 152.589858] check_local_cpu_capabilities+0x88/0x118 [ 152.589968] secondary_start_kernel+0xc4/0x168 [ 152.590530] Code: d53801e0 17ffff58 d5380600 17ffff56 (d4210000) [ 152.592215] ---[ end trace 80ea98416149c87e ]--- [ 152.592734] Kernel panic - not syncing: Attempted to kill the idle task! [ 152.593173] Kernel Offset: disabled [ 152.593501] CPU features: 0x0004,20c02008 [ 152.593678] Memory Limit: none [ 152.594208] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- [root@arch ~]# bash: echo: write error: Input/output error [root@arch ~]# [root@arch ~]# [root@arch ~]# echo HELO HELO Get rid of such bug, switching arm64 to use the common SMP stop code. Reported-by: Dave Martin Signed-off-by: Cristian Marussi --- arch/arm64/Kconfig | 3 +++ arch/arm64/kernel/smp.c | 29 ++++++----------------------- 2 files changed, 9 insertions(+), 23 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 3adcec05b1f6..3baa69ca4c55 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -276,6 +276,9 @@ config ARCH_ENABLE_MEMORY_HOTPLUG config SMP def_bool y +config ARCH_USE_COMMON_SMP_STOP + def_bool y if SMP + config KERNEL_MODE_NEON def_bool y diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 018a33e01b0e..473be3c23df7 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -953,33 +953,16 @@ void tick_broadcast(const struct cpumask *mask) } #endif -void smp_send_stop(void) +void arch_smp_cpus_stop_complete(void) { - unsigned long timeout; - - if (num_online_cpus() > 1) { - cpumask_t mask; - - cpumask_copy(&mask, cpu_online_mask); - cpumask_clear_cpu(smp_processor_id(), &mask); - - if (system_state <= SYSTEM_RUNNING) - pr_crit("SMP: stopping secondary CPUs\n"); - smp_cross_call(&mask, IPI_CPU_STOP); - } - - /* Wait up to one second for other CPUs to stop */ - timeout = USEC_PER_SEC; - while (num_online_cpus() > 1 && timeout--) - udelay(1); - - if (num_online_cpus() > 1) - pr_warning("SMP: failed to stop secondary CPUs %*pbl\n", - cpumask_pr_args(cpu_online_mask)); - sdei_mask_local_cpu(); } +void arch_smp_stop_call(cpumask_t *cpus) +{ + smp_cross_call(cpus, IPI_CPU_STOP); +} + #ifdef CONFIG_KEXEC_CORE void crash_smp_send_stop(void) { -- 2.17.1