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