From patchwork Fri Nov 28 16:16:13 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Thompson X-Patchwork-Id: 5404861 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 4DACB9F443 for ; Fri, 28 Nov 2014 16:20:26 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6BB0B2013A for ; Fri, 28 Nov 2014 16:20:24 +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 8B8612011B for ; Fri, 28 Nov 2014 16:20:23 +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 1XuOEz-0006r4-0o; Fri, 28 Nov 2014 16:17:53 +0000 Received: from mail-wg0-f48.google.com ([74.125.82.48]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XuOEM-0006Z6-OR for linux-arm-kernel@lists.infradead.org; Fri, 28 Nov 2014 16:17:16 +0000 Received: by mail-wg0-f48.google.com with SMTP id y19so9134464wgg.21 for ; Fri, 28 Nov 2014 08:16:56 -0800 (PST) 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=CDEbxUPYcfoC2H7IXpSXnfHHmM7/4dBLZReZ9wEbX5E=; b=EkJC8x8U/sDZuJVHtL6lN8OgWb47zXWA2vr01vb7gAlqbDbM6oNoKxzYOUUytb4t0Y oezv9OBWQWd0CZy85pWKaORKOjKPtaSrEswn+Cf5mdK5TqFQu4366meNCxPFywRt02Oh V3qzB2PYycSHmgXbWz3Jy20l+F19URPKUGESx6eNs623PPyRQKQAEzsh+cdcc0gWqJQD pyDH1hxGMHIKQJwz/syTErnPPWBib//spa6XqfL4xVFNs9IbHH6bCn7OMgeGXPIpZkqX hPatXe6Aw9RxswbOme7oHFyZvxrL9xfNUsIhqf6KlTA+BMDe/VLK1LcfXe/fsjXQ2JkN X4WQ== X-Gm-Message-State: ALoCoQkSc0BBrRHNpX95qAQcXAWk53cYW1KqLHamOneOcGI48z8EB8s16TZ4Y6f23gXt2Kz4ve3U X-Received: by 10.181.13.179 with SMTP id ez19mr11375734wid.65.1417191416542; Fri, 28 Nov 2014 08:16:56 -0800 (PST) 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 js5sm29576588wid.11.2014.11.28.08.16.54 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 28 Nov 2014 08:16:55 -0800 (PST) From: Daniel Thompson To: Thomas Gleixner , Jason Cooper Subject: [PATCH 3.18-rc4 v12 4/5] ARM: add basic support for on-demand backtrace of other CPUs Date: Fri, 28 Nov 2014 16:16:13 +0000 Message-Id: <1417191374-26719-5-git-send-email-daniel.thompson@linaro.org> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1417191374-26719-1-git-send-email-daniel.thompson@linaro.org> References: <1415968543-29469-1-git-send-email-daniel.thompson@linaro.org> <1417191374-26719-1-git-send-email-daniel.thompson@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141128_081714_973572_2D8E0C88 X-CRM114-Status: GOOD ( 16.16 ) X-Spam-Score: -0.7 (/) Cc: Daniel Thompson , linaro-kernel@lists.linaro.org, Russell King , patches@linaro.org, Stephen Boyd , linux-kernel@vger.kernel.org, Daniel Drake , Dmitry Pervushin , Dirk Behme , John Stultz , Tim Sander , Russell King , 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_LOW, T_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 53c15dec7af6..be1d07d59ee9 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 13396d3d600e..14c594a12bef 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; @@ -535,6 +539,21 @@ 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) @@ -614,6 +633,12 @@ 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); @@ -708,3 +733,40 @@ 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(); +}