From patchwork Sun Sep 14 11:57:14 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Thompson X-Patchwork-Id: 37383 Return-Path: X-Original-To: linaro@patches.linaro.org Delivered-To: linaro@patches.linaro.org Received: from mail-we0-f198.google.com (mail-we0-f198.google.com [74.125.82.198]) by ip-10-151-82-157.ec2.internal (Postfix) with ESMTPS id 87C68206A5 for ; Sun, 14 Sep 2014 11:59:30 +0000 (UTC) Received: by mail-we0-f198.google.com with SMTP id p10sf1516797wes.5 for ; Sun, 14 Sep 2014 04:59:29 -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=ksSKpckuqPYp3e7nR0REVZg+j3BG/t3NEGv+bZ64D/OKwbguQViK8qpxBcQ7rdjuEI 3svTKzb97mCj314szCk4A097+7KhWo9auvZzg1TNfFcisGA1V3Dk2p3MtCo798k4UxWi MDWZTK8dorCX9zF3dkPLi9nUkxtXIL1SGZ3YMHIJ4SMRRUQSIHADc1cArbRglyTmO9iN vhMPTUM5n96QWsTCE31aRZwvGoZ8Ew/KdD5AgpPZkOA4XNYRMByzl7NLSL0ji65XGnJc c7vTT6nWpjEKEzZZxsCdxD10pvhIKuH9LYCoPB4733IF3cS4gudyWviTxON53US1O1Aw X2Xw== X-Gm-Message-State: ALoCoQlWyNlYddLo6R99/66OJKhbl65VsrW9nbzHeGZ6YkzeWKz6jjHlxUFSHDKzWmm4qVjBzHiH X-Received: by 10.180.99.74 with SMTP id eo10mr3953057wib.2.1410695969688; Sun, 14 Sep 2014 04:59:29 -0700 (PDT) MIME-Version: 1.0 X-BeenThere: patchwork-forward@linaro.org Received: by 10.152.20.201 with SMTP id p9ls274916lae.15.gmail; Sun, 14 Sep 2014 04:59:29 -0700 (PDT) X-Received: by 10.112.8.99 with SMTP id q3mr1780800lba.85.1410695969278; Sun, 14 Sep 2014 04:59:29 -0700 (PDT) Received: from mail-la0-f53.google.com (mail-la0-f53.google.com [209.85.215.53]) by mx.google.com with ESMTPS id uo9si14626582lbb.134.2014.09.14.04.59.29 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sun, 14 Sep 2014 04:59:29 -0700 (PDT) Received-SPF: pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.215.53 as permitted sender) client-ip=209.85.215.53; Received: by mail-la0-f53.google.com with SMTP id ge10so3179883lab.40 for ; Sun, 14 Sep 2014 04:59:29 -0700 (PDT) X-Received: by 10.152.5.168 with SMTP id t8mr2502488lat.67.1410695969211; Sun, 14 Sep 2014 04:59:29 -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 of9csp74071lbb; Sun, 14 Sep 2014 04:59:28 -0700 (PDT) X-Received: by 10.180.107.194 with SMTP id he2mr4055369wib.72.1410695968583; Sun, 14 Sep 2014 04:59:28 -0700 (PDT) Received: from mail-wg0-f48.google.com (mail-wg0-f48.google.com [74.125.82.48]) by mx.google.com with ESMTPS id fl3si10645752wib.88.2014.09.14.04.59.28 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sun, 14 Sep 2014 04:59:28 -0700 (PDT) Received-SPF: pass (google.com: domain of daniel.thompson@linaro.org designates 74.125.82.48 as permitted sender) client-ip=74.125.82.48; Received: by mail-wg0-f48.google.com with SMTP id m15so2635765wgh.31 for ; Sun, 14 Sep 2014 04:59:28 -0700 (PDT) X-Received: by 10.180.104.201 with SMTP id gg9mr9027091wib.15.1410695968381; Sun, 14 Sep 2014 04:59:28 -0700 (PDT) Received: from harvey.bri.st.com ([212.183.140.14]) by mx.google.com with ESMTPSA id fh5sm7947027wib.5.2014.09.14.04.59.25 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 14 Sep 2014 04:59:27 -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 v6 5/6] ARM: add basic support for on-demand backtrace of other CPUs Date: Sun, 14 Sep 2014 12:57:14 +0100 Message-Id: <1410695835-10496-6-git-send-email-daniel.thompson@linaro.org> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1410695835-10496-1-git-send-email-daniel.thompson@linaro.org> References: <1410695835-10496-1-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 209.85.215.53 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(); +}