From patchwork Fri Sep 5 15:33:15 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Thompson X-Patchwork-Id: 4852911 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 0AEF59F2EC for ; Fri, 5 Sep 2014 15:36:27 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6D3992010E for ; Fri, 5 Sep 2014 15:36:25 +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 C4ACC20211 for ; Fri, 5 Sep 2014 15:36:23 +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 1XPvWb-0000pX-71; Fri, 05 Sep 2014 15:34:09 +0000 Received: from mail-wg0-f51.google.com ([74.125.82.51]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XPvWX-0000cz-Gd for linux-arm-kernel@lists.infradead.org; Fri, 05 Sep 2014 15:34:06 +0000 Received: by mail-wg0-f51.google.com with SMTP id l18so11936285wgh.22 for ; Fri, 05 Sep 2014 08:33:43 -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=/+96yEWfkxFwHBFjqx62ht8j6Wmq0SW+plNwxHeYZ1A=; b=DI7hRaDe5PjEFkBM/lRREMB1xM1aIcn7lOM6oPVYRLY5UFlQwrzXo6IGDyKR9l43f6 M3tXvKV1vCVCeJifK1kMpwZDzlLjkXAthtT754kMACJwv2ygn35ek9T4WlEtvpalaokd 3oj67KAy8ELAvQIFoTBmLR5tn6NSJ+a+62akTij8xVCrSwklkMYYMiAfZL6iQuKg2thM UPMWMCXfF4OcOnjL7W4Tb9vo6mTTouFTjM7IKrg7xBYJ93iaQgE2pPVAyOEOqw7N4ORB 3t+6/mOOMkMyzllJWXkds5iESI+QJTrzk6/U+5WXV5m/Tas/OETroHYprAPsxpyLCc7L v5vA== X-Gm-Message-State: ALoCoQktqeoxMq6NW65G19zFin8WthtJTQnY63DtDGQC0ivXSVhEKU/LLX9PDgB2Dvjve8wFQdKJ X-Received: by 10.180.20.196 with SMTP id p4mr4800376wie.56.1409931222197; Fri, 05 Sep 2014 08:33:42 -0700 (PDT) Received: from sundance.lan (cpc4-aztw19-0-0-cust157.18-1.cable.virginm.net. [82.33.25.158]) by mx.google.com with ESMTPSA id mz16sm2186860wic.13.2014.09.05.08.33.40 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 05 Sep 2014 08:33:41 -0700 (PDT) From: Daniel Thompson To: Russell King Subject: [PATCH v2 2/5] ARM: add basic support for on-demand backtrace of other CPUs Date: Fri, 5 Sep 2014 16:33:15 +0100 Message-Id: <1409931198-22600-3-git-send-email-daniel.thompson@linaro.org> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1409931198-22600-1-git-send-email-daniel.thompson@linaro.org> References: <1409846620-14542-1-git-send-email-daniel.thompson@linaro.org> <1409931198-22600-1-git-send-email-daniel.thompson@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140905_083405_703263_2197DC7B X-CRM114-Status: GOOD ( 17.06 ) X-Spam-Score: -0.7 (/) Cc: 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=-3.6 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 From: Russell King 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 --- 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(); +}