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arm64: kdump: implement machine_crash_shutdown()

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Primary kernel calls machine_crash_shutdown() to shut down non-boot cpus
and save registers' status in per-cpu ELF notes before starting crash
dump kernel. See kernel_kexec().
Even if not all secondary cpus have shut down, we do kdump anyway.

As we don't have to make non-boot(crashed) cpus offline (to preserve
correct status of cpus at crash dump) before shutting down, this patch
also adds a variant of smp_send_stop().

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: James Morse <james.morse@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
AKASHI Takahiro
2017-04-03 11:24:36 +09:00
committed by Catalin Marinas
parent 254a41c0ba
commit 78fd584cde
5 changed files with 167 additions and 6 deletions
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68
arch/arm64/kernel/smp.c
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@@ -39,6 +39,7 @@
#include <linux/completion.h>
#include <linux/of.h>
#include <linux/irq_work.h>
#include <linux/kexec.h>
#include <asm/alternative.h>
#include <asm/atomic.h>
@@ -76,6 +77,7 @@ enum ipi_msg_type {
IPI_RESCHEDULE,
IPI_CALL_FUNC,
IPI_CPU_STOP,
IPI_CPU_CRASH_STOP,
IPI_TIMER,
IPI_IRQ_WORK,
IPI_WAKEUP
@@ -756,6 +758,7 @@ static const char *ipi_types[NR_IPI] __tracepoint_string = {
S(IPI_RESCHEDULE, "Rescheduling interrupts"),
S(IPI_CALL_FUNC, "Function call interrupts"),
S(IPI_CPU_STOP, "CPU stop interrupts"),
S(IPI_CPU_CRASH_STOP, "CPU stop (for crash dump) interrupts"),
S(IPI_TIMER, "Timer broadcast interrupts"),
S(IPI_IRQ_WORK, "IRQ work interrupts"),
S(IPI_WAKEUP, "CPU wake-up interrupts"),
@@ -830,6 +833,29 @@ static void ipi_cpu_stop(unsigned int cpu)
cpu_relax();
}
#ifdef CONFIG_KEXEC_CORE
static atomic_t waiting_for_crash_ipi = ATOMIC_INIT(0);
#endif
static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs)
{
#ifdef CONFIG_KEXEC_CORE
crash_save_cpu(regs, cpu);
atomic_dec(&waiting_for_crash_ipi);
local_irq_disable();
#ifdef CONFIG_HOTPLUG_CPU
if (cpu_ops[cpu]->cpu_die)
cpu_ops[cpu]->cpu_die(cpu);
#endif
/* just in case */
cpu_park_loop();
#endif
}
/*
* Main handler for inter-processor interrupts
*/
@@ -860,6 +886,15 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
irq_exit();
break;
case IPI_CPU_CRASH_STOP:
if (IS_ENABLED(CONFIG_KEXEC_CORE)) {
irq_enter();
ipi_cpu_crash_stop(cpu, regs);
unreachable();
}
break;
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
case IPI_TIMER:
irq_enter();
@@ -932,6 +967,39 @@ void smp_send_stop(void)
cpumask_pr_args(cpu_online_mask));
}
#ifdef CONFIG_KEXEC_CORE
void smp_send_crash_stop(void)
{
cpumask_t mask;
unsigned long timeout;
if (num_online_cpus() == 1)
return;
cpumask_copy(&mask, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &mask);
atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
pr_crit("SMP: stopping secondary CPUs\n");
smp_cross_call(&mask, IPI_CPU_CRASH_STOP);
/* Wait up to one second for other CPUs to stop */
timeout = USEC_PER_SEC;
while ((atomic_read(&waiting_for_crash_ipi) > 0) && timeout--)
udelay(1);
if (atomic_read(&waiting_for_crash_ipi) > 0)
pr_warning("SMP: failed to stop secondary CPUs %*pbl\n",
cpumask_pr_args(&mask));
}
bool smp_crash_stop_failed(void)
{
return (atomic_read(&waiting_for_crash_ipi) > 0);
}
#endif
/*
* not supported here
*/