Currently arm64 has no implementation of arch_trigger_all_cpu_backtace. The patch provides one for arm64 systems that are built with CONFIG_USE_ICC_SYSREGS_FOR_IRQFLAGS (i.e. those that have a pseudo-NMI).
Signed-off-by: Daniel Thompson <[email protected]> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/hardirq.h | 2 +- arch/arm64/include/asm/irq.h | 5 +++ arch/arm64/include/asm/smp.h | 4 +++ arch/arm64/kernel/smp.c | 70 ++++++++++++++++++++++++++++++++++++++++ drivers/irqchip/irq-gic-v3.c | 28 ++++++++++++++++ 6 files changed, 109 insertions(+), 1 deletion(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 91c0babb6132..cb8d3dce73c3 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -76,6 +76,7 @@ config ARM64 select PERF_USE_VMALLOC select POWER_RESET select POWER_SUPPLY + select PRINTK_NMI_BACKTRACE if USE_ICC_SYSREGS_FOR_IRQFLAGS select RTC_LIB select SPARSE_IRQ select SYSCTL_EXCEPTION_TRACE diff --git a/arch/arm64/include/asm/hardirq.h b/arch/arm64/include/asm/hardirq.h index 6aae421f4d73..e8a3268a891c 100644 --- a/arch/arm64/include/asm/hardirq.h +++ b/arch/arm64/include/asm/hardirq.h @@ -20,7 +20,7 @@ #include <linux/threads.h> #include <asm/irq.h> -#define NR_IPI 5 +#define NR_IPI 6 typedef struct { unsigned int __softirq_pending; diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h index 94c53674a31d..4f974a2959bb 100644 --- a/arch/arm64/include/asm/irq.h +++ b/arch/arm64/include/asm/irq.h @@ -8,4 +8,9 @@ struct pt_regs; extern void migrate_irqs(void); extern void set_handle_irq(void (*handle_irq)(struct pt_regs *)); +#if defined CONFIG_SMP && defined CONFIG_USE_ICC_SYSREGS_FOR_IRQFLAGS +extern void arch_trigger_all_cpu_backtrace(bool); +#define arch_trigger_all_cpu_backtrace(x) arch_trigger_all_cpu_backtrace(x) +#endif + #endif diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h index 780f82c827b6..9b3b5663b88b 100644 --- a/arch/arm64/include/asm/smp.h +++ b/arch/arm64/include/asm/smp.h @@ -24,6 +24,10 @@ # error "<asm/smp.h> included in non-SMP build" #endif +#ifdef CONFIG_USE_ICC_SYSREGS_FOR_IRQFLAGS +#define SMP_IPI_NMI_MASK (1 << 5) +#endif + #define raw_smp_processor_id() (current_thread_info()->cpu) struct seq_file; diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 328b8ce4b007..9369eee1fa9f 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -68,6 +68,7 @@ enum ipi_msg_type { IPI_CPU_STOP, IPI_TIMER, IPI_IRQ_WORK, + IPI_CPU_BACKTRACE, }; /* @@ -485,6 +486,7 @@ static const char *ipi_types[NR_IPI] __tracepoint_string = { S(IPI_CPU_STOP, "CPU stop interrupts"), S(IPI_TIMER, "Timer broadcast interrupts"), S(IPI_IRQ_WORK, "IRQ work interrupts"), + S(IPI_CPU_BACKTRACE, "backtrace interrupts"), }; static void smp_cross_call(const struct cpumask *target, unsigned int ipinr) @@ -559,6 +561,66 @@ static void ipi_cpu_stop(unsigned int cpu) cpu_relax(); } +#ifdef CONFIG_USE_ICC_SYSREGS_FOR_IRQFLAGS + +/* For reliability, we're prepared to waste bits here. */ +static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly; + +void arch_trigger_all_cpu_backtrace(bool include_self) +{ + int i; + int this_cpu = get_cpu(); + + if (0 != printk_nmi_backtrace_prepare()) { + /* + * If there is already an nmi printk sequence in + * progress then just give up... + */ + put_cpu(); + return; + } + + cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask); + if (!include_self) + cpumask_clear_cpu(this_cpu, to_cpumask(backtrace_mask)); + + if (!cpumask_empty(to_cpumask(backtrace_mask))) { + pr_info("Sending NMI 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 < 3 * 1000; i++) { + if (cpumask_empty(to_cpumask(backtrace_mask))) + break; + mdelay(1); + touch_softlockup_watchdog(); + } + + printk_nmi_backtrace_complete(); + put_cpu(); +} + +void ipi_cpu_backtrace(struct pt_regs *regs) +{ + int cpu = smp_processor_id(); + + BUILD_BUG_ON(SMP_IPI_NMI_MASK != BIT(IPI_CPU_BACKTRACE)); + + if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { + printk_nmi_backtrace_this_cpu_begin(); + pr_warn("NMI backtrace for cpu %d\n", cpu); + show_regs(regs); + show_stack(NULL, NULL); + printk_nmi_backtrace_this_cpu_end(); + + cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); + } +} + +#endif /* CONFIG_USE_ICC_SYSREGS_FOR_IRQFLAGS */ + /* * Main handler for inter-processor interrupts */ @@ -605,6 +667,14 @@ void handle_IPI(int ipinr, struct pt_regs *regs) break; #endif +#ifdef CONFIG_USE_ICC_SYSREGS_FOR_IRQFLAGS + case IPI_CPU_BACKTRACE: + nmi_enter(); + ipi_cpu_backtrace(regs); + nmi_exit(); + break; +#endif + default: pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr); break; diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index 3923b2a2150c..bdb134ed4519 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -34,6 +34,16 @@ #include "irq-gic-common.h" #include "irqchip.h" +#ifndef SMP_IPI_NMI_MASK +#define SMP_IPI_NMI_MASK 0 +#endif + +/* + * Copied from arm-gic.h (which we cannot include here because it conflicts + * with arm-gic-v3.h) + */ +#define GIC_DIST_PRI 0x400 + struct redist_region { void __iomem *redist_base; phys_addr_t phys_base; @@ -438,6 +448,7 @@ static int gic_dist_supports_lpis(void) static void gic_cpu_init(void) { void __iomem *rbase; + unsigned long nmimask, hwirq; /* Register ourselves with the rest of the world */ if (gic_populate_rdist()) @@ -455,6 +466,23 @@ static void gic_cpu_init(void) /* initialise system registers */ gic_cpu_sys_reg_init(); + + /* Boost the priority of any IPI in the mask */ + nmimask = SMP_IPI_NMI_MASK; + for_each_set_bit(hwirq, &nmimask, 16) { + unsigned int pri_reg = (hwirq / 4) * 4; + u32 pri_mask = BIT(6 + ((hwirq % 4) * 8)); + u32 pri_val = readl_relaxed(rbase + GIC_DIST_PRI + pri_reg); + u32 actual; + + pri_mask |= BIT(7 + ((hwirq % 4) * 8)); + pri_val &= ~pri_mask; /* priority boost */ + writel_relaxed(pri_val, rbase + GIC_DIST_PRI + pri_reg); + + actual = readl_relaxed(rbase + GIC_DIST_PRI + pri_reg); + } + gic_dist_wait_for_rwp(); + gic_redist_wait_for_rwp(); } #ifdef CONFIG_SMP -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
