LXR linux/arch/mips/kernel/crash.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/kernel.h>
   3#include <linux/smp.h>
   4#include <linux/reboot.h>
   5#include <linux/kexec.h>
   6#include <linux/memblock.h>
   7#include <linux/crash_dump.h>
   8#include <linux/delay.h>
   9#include <linux/irq.h>
  10#include <linux/types.h>
  11#include <linux/sched.h>
  12#include <linux/sched/task_stack.h>
  13
  14/* This keeps a track of which one is crashing cpu. */
  15static int crashing_cpu = -1;
  16static cpumask_t cpus_in_crash = CPU_MASK_NONE;
  17
  18#ifdef CONFIG_SMP
  19static void crash_shutdown_secondary(void *passed_regs)
  20{
  21        struct pt_regs *regs = passed_regs;
  22        int cpu = smp_processor_id();
  23
  24        /*
  25         * If we are passed registers, use those.  Otherwise get the
  26         * regs from the last interrupt, which should be correct, as
  27         * we are in an interrupt.  But if the regs are not there,
  28         * pull them from the top of the stack.  They are probably
  29         * wrong, but we need something to keep from crashing again.
  30         */
  31        if (!regs)
  32                regs = get_irq_regs();
  33        if (!regs)
  34                regs = task_pt_regs(current);
  35
  36        if (!cpu_online(cpu))
  37                return;
  38
  39        /* We won't be sent IPIs any more. */
  40        set_cpu_online(cpu, false);
  41
  42        local_irq_disable();
  43        if (!cpumask_test_cpu(cpu, &cpus_in_crash))
  44                crash_save_cpu(regs, cpu);
  45        cpumask_set_cpu(cpu, &cpus_in_crash);
  46
  47        while (!atomic_read(&kexec_ready_to_reboot))
  48                cpu_relax();
  49
  50        kexec_reboot();
  51
  52        /* NOTREACHED */
  53}
  54
  55static void crash_kexec_prepare_cpus(void)
  56{
  57        static int cpus_stopped;
  58        unsigned int msecs;
  59        unsigned int ncpus;
  60
  61        if (cpus_stopped)
  62                return;
  63
  64        ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
  65
  66        smp_call_function(crash_shutdown_secondary, NULL, 0);
  67        smp_wmb();
  68
  69        /*
  70         * The crash CPU sends an IPI and wait for other CPUs to
  71         * respond. Delay of at least 10 seconds.
  72         */
  73        pr_emerg("Sending IPI to other cpus...\n");
  74        msecs = 10000;
  75        while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) {
  76                cpu_relax();
  77                mdelay(1);
  78        }
  79
  80        cpus_stopped = 1;
  81}
  82
  83/* Override the weak function in kernel/panic.c */
  84void crash_smp_send_stop(void)
  85{
  86        if (_crash_smp_send_stop)
  87                _crash_smp_send_stop();
  88
  89        crash_kexec_prepare_cpus();
  90}
  91
  92#else /* !defined(CONFIG_SMP)  */
  93static void crash_kexec_prepare_cpus(void) {}
  94#endif /* !defined(CONFIG_SMP)  */
  95
  96void default_machine_crash_shutdown(struct pt_regs *regs)
  97{
  98        local_irq_disable();
  99        crashing_cpu = smp_processor_id();
 100        crash_save_cpu(regs, crashing_cpu);
 101        crash_kexec_prepare_cpus();
 102        cpumask_set_cpu(crashing_cpu, &cpus_in_crash);
 103}
 104