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 pt_regs *regs)
  36 {
  37 #ifdef CONFIG_X86_32
  38         struct pt_regs fixed_regs;
  39 #endif
  40
  41 #ifdef CONFIG_X86_32
  42         if (!user_mode_vm(regs)) {
  43                 crash_fixup_ss_esp(&fixed_regs, regs);
  44                 regs = &fixed_regs;
  45         }
  46 #endif
  47         crash_save_cpu(regs, cpu);
  48
  49         /* Disable VMX or SVM if needed.
  50          *
  51          * We need to disable virtualization on all CPUs.
  52          * Having VMX or SVM enabled on any CPU may break rebooting
  53          * after the kdump kernel has finished its task.
  54          */
  55         cpu_emergency_vmxoff();
  56         cpu_emergency_svm_disable();
  57
  58         disable_local_APIC();
  59 }
  60
  61 static void kdump_nmi_shootdown_cpus(void)
  62 {
  63         in_crash_kexec = 1;
  64         nmi_shootdown_cpus(kdump_nmi_callback);
  65
  66         disable_local_APIC();
  67 }
  68
  69 #else
  70 static void kdump_nmi_shootdown_cpus(void)
  71 {
  72         /* There are no cpus to shootdown */
  73 }
  74 #endif
  75
  76 void native_machine_crash_shutdown(struct pt_regs *regs)
  77 {
  78         /* This function is only called after the system
  79          * has panicked or is otherwise in a critical state.
  80          * The minimum amount of code to allow a kexec'd kernel
  81          * to run successfully needs to happen here.
  82          *
  83          * In practice this means shooting down the other cpus in
  84          * an SMP system.
  85          */
  86         /* The kernel is broken so disable interrupts */
  87         local_irq_disable();
  88
  89         kdump_nmi_shootdown_cpus();
  90
  91         /* Booting kdump kernel with VMX or SVM enabled won't work,
  92          * because (among other limitations) we can't disable paging
  93          * with the virt flags.
  94          */
  95         cpu_emergency_vmxoff();
  96         cpu_emergency_svm_disable();
  97
  98         lapic_shutdown();
  99 #if defined(CONFIG_X86_IO_APIC)
 100         disable_IO_APIC();
 101 #endif
 102 #ifdef CONFIG_HPET_TIMER
 103         hpet_disable();
 104 #endif
 105         crash_save_cpu(regs, safe_smp_processor_id());
 106 }