From: Sumit Garg sumit.garg@linaro.org
maillist inclusion category: feature bugzilla: 49593 CVE: NA Reference: https://www.spinics.net/lists/arm-kernel/msg851005.html
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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 sumit.garg@linaro.org Signed-off-by: Wei Li liwei391@huawei.com Reviewed-by: Xie XiuQi xiexiuqi@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Signed-off-by: Ruan Jinjie ruanjinjie@huawei.com --- arch/arm64/include/asm/irq.h | 6 ++++++ arch/arm64/kernel/ipi_nmi.c | 18 ++++++++++++++++-- 2 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h index fac08e18bcd5..9e926b4f7d47 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 bool arch_trigger_cpumask_backtrace(const cpumask_t *mask, + bool exclude_self); +#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace +#endif + struct pt_regs;
int set_handle_irq(void (*handle_irq)(struct pt_regs *)); diff --git a/arch/arm64/kernel/ipi_nmi.c b/arch/arm64/kernel/ipi_nmi.c index a945dcf8015f..597dcf7fb59c 100644 --- a/arch/arm64/kernel/ipi_nmi.c +++ b/arch/arm64/kernel/ipi_nmi.c @@ -8,6 +8,7 @@
#include <linux/interrupt.h> #include <linux/irq.h> +#include <linux/nmi.h> #include <linux/smp.h>
#include <asm/nmi.h> @@ -31,11 +32,24 @@ void arm64_send_nmi(cpumask_t *mask) __ipi_send_mask(ipi_nmi_desc, mask); }
+bool arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) +{ + if (!ipi_nmi_desc) + return false; + + nmi_trigger_cpumask_backtrace(mask, exclude_self, arm64_send_nmi); + + return true; +} + static irqreturn_t ipi_nmi_handler(int irq, void *data) { - /* nop, NMI handlers for special features can be added here. */ + irqreturn_t ret = IRQ_NONE; + + if (nmi_cpu_backtrace(get_irq_regs())) + ret = IRQ_HANDLED;
- return IRQ_NONE; + return ret; }
void dynamic_ipi_setup(int cpu)