[PATCH v5 5/5] arm64: ipi_nmi: Add support for NMI backtrace
From: Sumit Garg <hidden>
Date: 2020-10-14 11:13:25
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Enable NMI backtrace support on arm64 using IPI turned as an NMI leveraging pseudo NMIs support. It is now possible for users to get a backtrace of a CPU stuck in hard-lockup using magic SYSRQ. Signed-off-by: Sumit Garg <redacted> --- arch/arm64/include/asm/irq.h | 6 ++++++ arch/arm64/kernel/ipi_nmi.c | 12 +++++++++++- 2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h
index b2b0c64..e840bf1 100644
--- a/arch/arm64/include/asm/irq.h
+++ b/arch/arm64/include/asm/irq.h@@ -6,6 +6,12 @@ #include <asm-generic/irq.h> +#ifdef CONFIG_SMP +extern void arch_trigger_cpumask_backtrace(const cpumask_t *mask, + bool exclude_self); +#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace +#endif + struct pt_regs; static inline int nr_legacy_irqs(void)
diff --git a/arch/arm64/kernel/ipi_nmi.c b/arch/arm64/kernel/ipi_nmi.c
index e0a9e03..e1dc19d 100644
--- a/arch/arm64/kernel/ipi_nmi.c
+++ b/arch/arm64/kernel/ipi_nmi.c@@ -9,6 +9,7 @@ #include <linux/interrupt.h> #include <linux/irq.h> #include <linux/kgdb.h> +#include <linux/nmi.h> #include <linux/smp.h> #include <asm/nmi.h>
@@ -25,12 +26,21 @@ void arch_send_call_nmi_func_ipi_mask(cpumask_t *mask) __ipi_send_mask(ipi_desc, mask); } +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) +{ + nmi_trigger_cpumask_backtrace(mask, exclude_self, + arch_send_call_nmi_func_ipi_mask); +} + static irqreturn_t ipi_nmi_handler(int irq, void *data) { unsigned int cpu = smp_processor_id(); - ipi_kgdb_nmicallback(cpu, get_irq_regs()); + if (nmi_cpu_backtrace(get_irq_regs())) + goto out; + ipi_kgdb_nmicallback(cpu, get_irq_regs()); +out: return IRQ_HANDLED; }
--
2.7.4
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