arch/i386/kernel/crash_dump.c

   1 /*
   2  * Architecture specific (i386) functions for kexec based crash dumps.
   3  *
   4  * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
   5  *
   6  * Copyright (C) IBM Corporation, 2004. All rights reserved.
   7  *
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/smp.h>
  14 #include <linux/irq.h>
  15
  16 #include <asm/crash_dump.h>
  17 #include <asm/processor.h>
  18 #include <asm/hardirq.h>
  19 #include <asm/nmi.h>
  20 #include <asm/hw_irq.h>
  21
  22 struct pt_regs crash_smp_regs[NR_CPUS];
  23 long crash_smp_current_task[NR_CPUS];
  24
  25 #ifdef CONFIG_SMP
  26 static atomic_t waiting_for_dump_ipi;
  27 static int crash_dump_expect_ipi[NR_CPUS];
  28 extern void crash_dump_send_ipi(void);
  29 extern void stop_this_cpu(void *);
  30
  31 static int crash_dump_nmi_callback(struct pt_regs *regs, int cpu)
  32 {
  33         if (!crash_dump_expect_ipi[cpu])
  34                 return 0;
  35
  36         crash_dump_expect_ipi[cpu] = 0;
  37         crash_dump_save_this_cpu(regs, cpu);
  38         atomic_dec(&waiting_for_dump_ipi);
  39
  40         stop_this_cpu(NULL);
  41
  42         return 1;
  43 }
  44
  45 void __crash_dump_stop_cpus(void)
  46 {
  47         int i, cpu, other_cpus;
  48
  49         preempt_disable();
  50         cpu = smp_processor_id();
  51         other_cpus = num_online_cpus()-1;
  52
  53         if (other_cpus > 0) {
  54                 atomic_set(&waiting_for_dump_ipi, other_cpus);
  55
  56                 for (i = 0; i < NR_CPUS; i++)
  57                         crash_dump_expect_ipi[i] = (i != cpu && cpu_online(i));
  58
  59                 set_nmi_callback(crash_dump_nmi_callback);
  60                 /* Ensure the new callback function is set before sending
  61                  * out the IPI
  62                  */
  63                 wmb();
  64
  65                 crash_dump_send_ipi();
  66                 while (atomic_read(&waiting_for_dump_ipi) > 0)
  67                         cpu_relax();
  68
  69                 unset_nmi_callback();
  70         } else {
  71                 local_irq_disable();
  72                 disable_local_APIC();
  73                 local_irq_enable();
  74         }
  75         preempt_enable();
  76 }
  77 #else
  78 void __crash_dump_stop_cpus(void) {}
  79 #endif
  80
  81 void crash_get_current_regs(struct pt_regs *regs)
  82 {
  83         __asm__ __volatile__("movl %%ebx,%0" : "=m"(regs->ebx));
  84         __asm__ __volatile__("movl %%ecx,%0" : "=m"(regs->ecx));
  85         __asm__ __volatile__("movl %%edx,%0" : "=m"(regs->edx));
  86         __asm__ __volatile__("movl %%esi,%0" : "=m"(regs->esi));
  87         __asm__ __volatile__("movl %%edi,%0" : "=m"(regs->edi));
  88         __asm__ __volatile__("movl %%ebp,%0" : "=m"(regs->ebp));
  89         __asm__ __volatile__("movl %%eax,%0" : "=m"(regs->eax));
  90         __asm__ __volatile__("movl %%esp,%0" : "=m"(regs->esp));
  91         __asm__ __volatile__("movw %%ss, %%ax;" :"=a"(regs->xss));
  92         __asm__ __volatile__("movw %%cs, %%ax;" :"=a"(regs->xcs));
  93         __asm__ __volatile__("movw %%ds, %%ax;" :"=a"(regs->xds));
  94         __asm__ __volatile__("movw %%es, %%ax;" :"=a"(regs->xes));
  95         __asm__ __volatile__("pushfl; popl %0" :"=m"(regs->eflags));
  96
  97         regs->eip = (unsigned long)current_text_addr();
  98 }
  99
 100 void crash_dump_save_this_cpu(struct pt_regs *regs, int cpu)
 101 {
 102         crash_smp_current_task[cpu] = (long)current;
 103         crash_smp_regs[cpu] = *regs;
 104 }
 105