Commit 26d27c01 authored by Sumit Garg's avatar Sumit Garg Committed by Zheng Zengkai
Browse files

arm64: ipi_nmi: Add support for NMI backtrace 

maillist inclusion
category: feature
bugzilla: 49593
CVE: NA
Reference: https://www.spinics.net/lists/arm-kernel/msg851005.html



-------------------------------------------------

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: default avatarSumit Garg <sumit.garg@linaro.org>
Signed-off-by: default avatarWei Li <liwei391@huawei.com>
Reviewed-by: default avatarXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 755a12c0

arch/arm64/include/asm/irq.h

+6 −0
Original line number Diff line number Diff line
@@ -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;



static inline int nr_legacy_irqs(void)

arch/arm64/kernel/ipi_nmi.c

+16 −2
Original line number Diff line number Diff line
@@ -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)