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: 37531 Return-Path: X-Original-To: linaro@patches.linaro.org Delivered-To: linaro@patches.linaro.org Received: from mail-lb0-f197.google.com (mail-lb0-f197.google.com [209.85.217.197]) by ip-10-151-82-157.ec2.internal (Postfix) with ESMTPS id 9BDA22057E for ; Wed, 17 Sep 2014 16:10:32 +0000 (UTC) Received: by mail-lb0-f197.google.com with SMTP id l4sf426337lbv.8 for ; Wed, 17 Sep 2014 09:10:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:delivered-to:from:to:cc:subject :date:message-id:in-reply-to:references:x-original-sender :x-original-authentication-results:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-unsubscribe; bh=MWOlSJaxt3du8IqhmP9HgCt3yI4o/voVsQcK6tMOI1Y=; b=RdabI2UqqYfOMqDGugYtxrMXHwYGM245p2Gy5r0I2aqtqSyWngnJDC6WV6b8ZofEUO Upo4USKWfAlYpB8x8rhhLlAY7WUmkERGl8loJnw4uoELBrDA7zxZrhUg3dXSUc74LfOx SUUzlDO2HNVvVe5O9LzWQMLOb6yJsAS33wjZBJCt5Io9NJ9KNtER9DfLJ2Nz5JzN35G5 mNff1sVV/fypL6EMaub4+jlAIqSoq1gk0MW+ov3MPxaZODcfjAM/xIKyb0m+nvohF3H/ mOdNz6kXlei76Tyrb2TSI22tQBlDytZLwHm9Q1B5qybPUnIegyQVXg0PAdFlAc5k4+tL v3Sg== X-Gm-Message-State: ALoCoQniNy4AyMf4DNC+EtDQFzNRdvxeKbOfmY4RpM+/ROR8clrMPvrqPVPFU7CW0wtpe+r9AsOK X-Received: by 10.181.28.169 with SMTP id jp9mr18519wid.6.1410970231435; Wed, 17 Sep 2014 09:10:31 -0700 (PDT) MIME-Version: 1.0 X-BeenThere: patchwork-forward@linaro.org Received: by 10.152.8.41 with SMTP id o9ls130888laa.52.gmail; Wed, 17 Sep 2014 09:10:31 -0700 (PDT) X-Received: by 10.152.8.131 with SMTP id r3mr4493185laa.3.1410970231284; Wed, 17 Sep 2014 09:10:31 -0700 (PDT) Received: from mail-la0-f51.google.com (mail-la0-f51.google.com [209.85.215.51]) by mx.google.com with ESMTPS id n3si29269299lae.22.2014.09.17.09.10.31 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 17 Sep 2014 09:10:31 -0700 (PDT) Received-SPF: pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.215.51 as permitted sender) client-ip=209.85.215.51; Received: by mail-la0-f51.google.com with SMTP id gi9so2184792lab.10 for ; Wed, 17 Sep 2014 09:10:31 -0700 (PDT) X-Received: by 10.112.4.33 with SMTP id h1mr41814734lbh.67.1410970231217; Wed, 17 Sep 2014 09:10:31 -0700 (PDT) X-Forwarded-To: patchwork-forward@linaro.org X-Forwarded-For: patch@linaro.org patchwork-forward@linaro.org Delivered-To: patches@linaro.org Received: by 10.112.130.169 with SMTP id of9csp608002lbb; Wed, 17 Sep 2014 09:10:30 -0700 (PDT) X-Received: by 10.68.216.35 with SMTP id on3mr13666855pbc.34.1410970228884; Wed, 17 Sep 2014 09:10:28 -0700 (PDT) Received: from mail-pd0-f182.google.com (mail-pd0-f182.google.com [209.85.192.182]) by mx.google.com with ESMTPS id ia9si35599165pbc.55.2014.09.17.09.10.28 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 17 Sep 2014 09:10:28 -0700 (PDT) Received-SPF: pass (google.com: domain of daniel.thompson@linaro.org designates 209.85.192.182 as permitted sender) client-ip=209.85.192.182; Received: by mail-pd0-f182.google.com with SMTP id w10so2432241pde.27 for ; Wed, 17 Sep 2014 09:10:28 -0700 (PDT) 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 Cc: Daniel Thompson , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, patches@linaro.org, linaro-kernel@lists.linaro.org, John Stultz , Thomas Gleixner , Sumit Semwal , 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-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: daniel.thompson@linaro.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.215.51 as permitted sender) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Precedence: list Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org List-ID: X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , 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(); +}