From patchwork Wed Sep 17 16:10:17 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Thompson X-Patchwork-Id: 4925321 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id F3588BEEA5 for ; Wed, 17 Sep 2014 16:13:49 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B7B412010F for ; Wed, 17 Sep 2014 16:13:48 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 82A8E20114 for ; Wed, 17 Sep 2014 16:13:46 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XUHpJ-0005Em-9a; Wed, 17 Sep 2014 16:11:29 +0000 Received: from mail-pa0-f43.google.com ([209.85.220.43]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XUHof-0004ZV-Di for linux-arm-kernel@lists.infradead.org; Wed, 17 Sep 2014 16:10:50 +0000 Received: by mail-pa0-f43.google.com with SMTP id fa1so2451593pad.16 for ; Wed, 17 Sep 2014 09:10:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=MWOlSJaxt3du8IqhmP9HgCt3yI4o/voVsQcK6tMOI1Y=; b=VMgFWNhDlNUjX3NWZol0P2gjC/qr4Hy7Eor87KvCcYhWyC89e6FbovSpExzcj+//oB t++GtjnB0Qqycr9YmkRcAt429OTVHy9U6Knv0BVo46wBG63C0QCPmQ9NT54GwxIw94wF 77breJ1QmMk2Tkfy6dB9PQk39AttCfptFVoYDbM0unAAih9GiyHiIyvvsmTBufL7T52U wwBDyfjFcKlWoRQ98NDImntSUWmNQDUZUOyqntGjMM3U4rqh/yshkTUmRTWEA3e/OKcC Gg7Qp74h0KT4vKrljQaJhHu92dkH4Zrkrkts1Ev4nQPpCiYKOGyiFD/1qmSqY8BxkUMS nK/w== X-Gm-Message-State: ALoCoQkSetR3DWQrhi1ZI+L3B/StPf/pIePAFub1y7yoMqQ+vr96lOrDlmTUd0BQh0r55hfEp+v6 X-Received: by 10.70.130.195 with SMTP id og3mr73835379pdb.59.1410970228191; Wed, 17 Sep 2014 09:10:28 -0700 (PDT) Received: from harvey.bri.st.com ([38.126.120.10]) by mx.google.com with ESMTPSA id pd7sm17841758pac.33.2014.09.17.09.10.27 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 17 Sep 2014 09:10:27 -0700 (PDT) From: Daniel Thompson To: Russell King Subject: [PATCH 3.17-rc4 v7 5/6] ARM: add basic support for on-demand backtrace of other CPUs Date: Wed, 17 Sep 2014 09:10:17 -0700 Message-Id: <1410970218-28847-6-git-send-email-daniel.thompson@linaro.org> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1410970218-28847-1-git-send-email-daniel.thompson@linaro.org> References: <1410970218-28847-1-git-send-email-daniel.thompson@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140917_091049_532756_E2CFDDC1 X-CRM114-Status: GOOD ( 16.82 ) X-Spam-Score: -0.9 (/) Cc: Daniel Thompson , linaro-kernel@lists.linaro.org, patches@linaro.org, linux-kernel@vger.kernel.org, John Stultz , Russell King , Thomas Gleixner , Sumit Semwal , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add basic infrastructure for triggering a backtrace of other CPUs via an IPI, preferably at FIQ level. It is intended that this shall be used for cases where we have detected that something has already failed in the kernel. Signed-off-by: Russell King Signed-off-by: Daniel Thompson --- arch/arm/include/asm/irq.h | 5 ++++ arch/arm/kernel/smp.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 67 insertions(+) diff --git a/arch/arm/include/asm/irq.h b/arch/arm/include/asm/irq.h index 53c15de..be1d07d 100644 --- a/arch/arm/include/asm/irq.h +++ b/arch/arm/include/asm/irq.h @@ -35,6 +35,11 @@ extern void (*handle_arch_irq)(struct pt_regs *); extern void set_handle_irq(void (*handle_irq)(struct pt_regs *)); #endif +#ifdef CONFIG_SMP +extern void arch_trigger_all_cpu_backtrace(bool); +#define arch_trigger_all_cpu_backtrace(x) arch_trigger_all_cpu_backtrace(x) +#endif + #endif #endif diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 9388a3d..94959f9 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -72,8 +72,12 @@ enum ipi_msg_type { IPI_CPU_STOP, IPI_IRQ_WORK, IPI_COMPLETION, + IPI_CPU_BACKTRACE, }; +/* For reliability, we're prepared to waste bits here. */ +static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly; + static DECLARE_COMPLETION(cpu_running); static struct smp_operations smp_ops; @@ -539,6 +543,21 @@ static void ipi_cpu_stop(unsigned int cpu) cpu_relax(); } +static void ipi_cpu_backtrace(struct pt_regs *regs) +{ + int cpu = smp_processor_id(); + + if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { + static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED; + + arch_spin_lock(&lock); + printk(KERN_WARNING "FIQ backtrace for cpu %d\n", cpu); + show_regs(regs); + arch_spin_unlock(&lock); + cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); + } +} + static DEFINE_PER_CPU(struct completion *, cpu_completion); int register_ipi_completion(struct completion *completion, int cpu) @@ -618,6 +637,12 @@ void handle_IPI(int ipinr, struct pt_regs *regs) irq_exit(); break; + case IPI_CPU_BACKTRACE: + irq_enter(); + ipi_cpu_backtrace(regs); + irq_exit(); + break; + default: printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr); @@ -712,3 +737,40 @@ static int __init register_cpufreq_notifier(void) core_initcall(register_cpufreq_notifier); #endif + +void arch_trigger_all_cpu_backtrace(bool include_self) +{ + static unsigned long backtrace_flag; + int i, cpu = get_cpu(); + + if (test_and_set_bit(0, &backtrace_flag)) { + /* + * If there is already a trigger_all_cpu_backtrace() in progress + * (backtrace_flag == 1), don't output double cpu dump infos. + */ + put_cpu(); + return; + } + + cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask); + if (!include_self) + cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); + + if (!cpumask_empty(to_cpumask(backtrace_mask))) { + pr_info("Sending FIQ to %s CPUs:\n", + (include_self ? "all" : "other")); + smp_cross_call(to_cpumask(backtrace_mask), IPI_CPU_BACKTRACE); + } + + /* Wait for up to 10 seconds for all CPUs to do the backtrace */ + for (i = 0; i < 10 * 1000; i++) { + if (cpumask_empty(to_cpumask(backtrace_mask))) + break; + + mdelay(1); + } + + clear_bit(0, &backtrace_flag); + smp_mb__after_atomic(); + put_cpu(); +}