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