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Commit 2d7b3c64 authored by Russell King's avatar Russell King
Browse files

ARM: kexec: fix kdump register saving on panic() 



When a panic() occurs, the kexec code uses smp_send_stop() to stop
the other CPUs, but this results in the CPU register state not being
saved, and gdb is unable to inspect the state of other CPUs.

Commit 0ee59413 ("x86/panic: replace smp_send_stop() with kdump
friendly version in panic path") addressed the issue on x86, but
ignored other architectures.  Address the issue on ARM by splitting
out the crash stop implementation to crash_smp_send_stop() and
adding the necessary protection.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent f2ae9de0

arch/arm/kernel/machine_kexec.c

+22 −12
Original line number Diff line number Diff line
@@ -95,6 +95,27 @@ void machine_crash_nonpanic_core(void *unused) 
		cpu_relax();

}



void crash_smp_send_stop(void)

{

	static int cpus_stopped;

	unsigned long msecs;



	if (cpus_stopped)

		return;



	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);

	smp_call_function(machine_crash_nonpanic_core, NULL, false);

	msecs = 1000; /* Wait at most a second for the other cpus to stop */

	while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {

		mdelay(1);

		msecs--;

	}

	if (atomic_read(&waiting_for_crash_ipi) > 0)

		pr_warn("Non-crashing CPUs did not react to IPI\n");



	cpus_stopped = 1;

}



static void machine_kexec_mask_interrupts(void)

{

	unsigned int i;
@@ -120,19 +141,8 @@ static void machine_kexec_mask_interrupts(void) 


void machine_crash_shutdown(struct pt_regs *regs)

{

	unsigned long msecs;



	local_irq_disable();



	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);

	smp_call_function(machine_crash_nonpanic_core, NULL, false);

	msecs = 1000; /* Wait at most a second for the other cpus to stop */

	while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {

		mdelay(1);

		msecs--;

	}

	if (atomic_read(&waiting_for_crash_ipi) > 0)

		pr_warn("Non-crashing CPUs did not react to IPI\n");

	crash_smp_send_stop();



	crash_save_cpu(regs, smp_processor_id());

	machine_kexec_mask_interrupts();