arch/x86/kernel/crash.c

   1 /*
   2  * Architecture specific (i386/x86_64) 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/reboot.h>
  15 #include <linux/kexec.h>
  16 #include <linux/delay.h>
  17 #include <linux/elf.h>
  18 #include <linux/elfcore.h>
  19
  20 #include <asm/processor.h>
  21 #include <asm/hardirq.h>
  22 #include <asm/nmi.h>
  23 #include <asm/hw_irq.h>
  24 #include <asm/apic.h>
  25 #include <asm/hpet.h>
  26 #include <linux/kdebug.h>
  27 #include <asm/cpu.h>
  28 #include <asm/reboot.h>
  29 #include <asm/virtext.h>
  30
  31 int in_crash_kexec;
  32
  33 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
  34
  35 static void kdump_nmi_callback(int cpu, struct die_args *args)
  36 {
  37         struct pt_regs *regs;
  38 #ifdef CONFIG_X86_32
  39         struct pt_regs fixed_regs;
  40 #endif
  41
  42         regs = args->regs;
  43
  44 #ifdef CONFIG_X86_32
  45         if (!user_mode_vm(regs)) {
  46                 crash_fixup_ss_esp(&fixed_regs, regs);
  47                 regs = &fixed_regs;
  48         }
  49 #endif
  50         crash_save_cpu(regs, cpu);
  51
  52         /* Disable VMX or SVM if needed.
  53          *
  54          * We need to disable virtualization on all CPUs.
  55          * Having VMX or SVM enabled on any CPU may break rebooting
  56          * after the kdump kernel has finished its task.
  57          */
  58         cpu_emergency_vmxoff();
  59         cpu_emergency_svm_disable();
  60
  61         disable_local_APIC();
  62 }
  63
  64 static void kdump_nmi_shootdown_cpus(void)
  65 {
  66         in_crash_kexec = 1;
  67         nmi_shootdown_cpus(kdump_nmi_callback);
  68
  69         disable_local_APIC();
  70 }
  71
  72 #else
  73 static void kdump_nmi_shootdown_cpus(void)
  74 {
  75         /* There are no cpus to shootdown */
  76 }
  77 #endif
  78
  79 void native_machine_crash_shutdown(struct pt_regs *regs)
  80 {
  81         /* This function is only called after the system
  82          * has panicked or is otherwise in a critical state.
  83          * The minimum amount of code to allow a kexec'd kernel
  84          * to run successfully needs to happen here.
  85          *
  86          * In practice this means shooting down the other cpus in
  87          * an SMP system.
  88          */
  89         /* The kernel is broken so disable interrupts */
  90         local_irq_disable();
  91
  92         kdump_nmi_shootdown_cpus();
  93
  94         /* Booting kdump kernel with VMX or SVM enabled won't work,
  95          * because (among other limitations) we can't disable paging
  96          * with the virt flags.
  97          */
  98         cpu_emergency_vmxoff();
  99         cpu_emergency_svm_disable();
 100
 101         lapic_shutdown();
 102 #if defined(CONFIG_X86_IO_APIC)
 103         disable_IO_APIC();
 104 #endif
 105 #ifdef CONFIG_HPET_TIMER
 106         hpet_disable();
 107 #endif
 108         crash_save_cpu(regs, safe_smp_processor_id());
 109 }