Linux Kernel  3.7.1
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crash.c
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1 /*
2  * Architecture specific (i386/x86_64) functions for kexec based crash dumps.
3  *
4  * Created by: Hariprasad Nellitheertha ([email protected])
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 
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 
59 }
60 
61 static void kdump_nmi_shootdown_cpus(void)
62 {
63  in_crash_kexec = 1;
64  nmi_shootdown_cpus(kdump_nmi_callback);
65 
67 }
68 
69 #else
70 static void kdump_nmi_shootdown_cpus(void)
71 {
72  /* There are no cpus to shootdown */
73 }
74 #endif
75 
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 */
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 
99 #if defined(CONFIG_X86_IO_APIC)
100  disable_IO_APIC();
101 #endif
102 #ifdef CONFIG_HPET_TIMER
103  hpet_disable();
104 #endif
106 }