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/init.h>
   9 #include <linux/irq.h>
  10 #include <linux/types.h>
  11 #include <linux/sched.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 (!cpu_isset(cpu, cpus_in_crash))
  40                 crash_save_cpu(regs, cpu);
  41         cpu_set(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         unsigned int msecs;
  52
  53         unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
  54
  55         dump_send_ipi(crash_shutdown_secondary);
  56         smp_wmb();
  57
  58         /*
  59          * The crash CPU sends an IPI and wait for other CPUs to
  60          * respond. Delay of at least 10 seconds.
  61          */
  62         pr_emerg("Sending IPI to other cpus...\n");
  63         msecs = 10000;
  64         while ((cpus_weight(cpus_in_crash) < ncpus) && (--msecs > 0)) {
  65                 cpu_relax();
  66                 mdelay(1);
  67         }
  68 }
  69
  70 #else /* !defined(CONFIG_SMP)  */
  71 static void crash_kexec_prepare_cpus(void) {}
  72 #endif /* !defined(CONFIG_SMP)  */
  73
  74 void default_machine_crash_shutdown(struct pt_regs *regs)
  75 {
  76         local_irq_disable();
  77         crashing_cpu = smp_processor_id();
  78         crash_save_cpu(regs, crashing_cpu);
  79         crash_kexec_prepare_cpus();
  80         cpu_set(crashing_cpu, cpus_in_crash);
  81 }