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Commit 46dba4c5 authored by Rohit Vaswani's avatar Rohit Vaswani Committed by Runmin Wang
Browse files

ARM64: smp: Save CPU registers before IPI_CPU_STOP processing 



When a kernel panic occurs on one CPU, other CPUs are instructed to stop
execution via the IPI_CPU_STOP message. These other CPUs dump their stack,
which may not be good enough to reconstruct their context to perform
post-mortem analysis. Dump each CPU's context (before it started
processing the IPI) into a globally accessible structure and print them on
the dmesg/console to allow for easier post-mortem debugging.

Change-Id: Ifd7589af4327992540196c87f8b640045d7eaf19
Signed-off-by: default avatarRohit Vaswani <rvaswani@codeaurora.org>
[abhimany: resolve trivial merge conflic]
Signed-off-by: default avatarAbhimanyu Kapur <abhimany@codeaurora.org>
Signed-off-by: default avatarKyle Yan <kyan@codeaurora.org>
parent 71ad6b09

arch/arm64/kernel/smp.c

+8 −2
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ 
#include <asm/tlbflush.h>

#include <asm/ptrace.h>

#include <asm/virt.h>

#include <asm/system_misc.h>



#define CREATE_TRACE_POINTS

#include <trace/events/ipi.h>
@@ -841,15 +842,20 @@ void arch_irq_work_raise(void) 
#endif



static DEFINE_RAW_SPINLOCK(stop_lock);



DEFINE_PER_CPU(struct pt_regs, regs_before_stop);



/*

 * ipi_cpu_stop - handle IPI from smp_send_stop()

 */

static void ipi_cpu_stop(unsigned int cpu)

static void ipi_cpu_stop(unsigned int cpu, struct pt_regs *regs)

{

	if (system_state == SYSTEM_BOOTING ||

	    system_state == SYSTEM_RUNNING) {

		per_cpu(regs_before_stop, cpu) = *regs;

		raw_spin_lock(&stop_lock);

		pr_crit("CPU%u: stopping\n", cpu);

		__show_regs(regs);

		dump_stack();

		raw_spin_unlock(&stop_lock);

	}
@@ -912,7 +918,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs) 


	case IPI_CPU_STOP:

		irq_enter();

		ipi_cpu_stop(cpu);

		ipi_cpu_stop(cpu, regs);

		irq_exit();

		break;