arch/mips/kernel/crash.c

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