x86 kdump: extract kdump-specific code from crash_nmi_callback()
[deliverable/linux.git] / arch / x86 / kernel / crash.c
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5033cba0 1/*
62a31a03 2 * Architecture specific (i386/x86_64) functions for kexec based crash dumps.
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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>
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14#include <linux/reboot.h>
15#include <linux/kexec.h>
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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>
19842d67 24#include <asm/apic.h>
0c1b2724 25#include <asm/hpet.h>
1eeb66a1 26#include <linux/kdebug.h>
ce53af94 27#include <asm/smp.h>
ed23dc6f 28#include <asm/reboot.h>
2fbe7b25 29
c4ac4263 30#include <mach_ipi.h>
5033cba0 31
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32/* This keeps a track of which one is crashing cpu. */
33static int crashing_cpu;
5033cba0 34
e78a887a 35#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
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36static atomic_t waiting_for_crash_ipi;
37
a7d41820 38static void kdump_nmi_callback(int cpu, struct die_args *args)
c4ac4263 39{
2fbe7b25 40 struct pt_regs *regs;
1fb473d8 41#ifdef CONFIG_X86_32
4d55476c 42 struct pt_regs fixed_regs;
62a31a03 43#endif
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44
45 regs = args->regs;
46
47#ifdef CONFIG_X86_32
48 if (!user_mode_vm(regs)) {
49 crash_fixup_ss_esp(&fixed_regs, regs);
50 regs = &fixed_regs;
51 }
52#endif
53 crash_save_cpu(regs, cpu);
54
55 disable_local_APIC();
56}
57
58static int crash_nmi_callback(struct notifier_block *self,
59 unsigned long val, void *data)
60{
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61 int cpu;
62
260d6790 63 if (val != DIE_NMI_IPI)
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64 return NOTIFY_OK;
65
2fbe7b25 66 cpu = raw_smp_processor_id();
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67
68 /* Don't do anything if this handler is invoked on crashing cpu.
69 * Otherwise, system will completely hang. Crashing cpu can get
70 * an NMI if system was initially booted with nmi_watchdog parameter.
71 */
72 if (cpu == crashing_cpu)
260d6790 73 return NOTIFY_STOP;
c4ac4263 74 local_irq_disable();
4d55476c 75
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76 kdump_nmi_callback(cpu, (struct die_args *)data);
77
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78 atomic_dec(&waiting_for_crash_ipi);
79 /* Assume hlt works */
f2ab4461 80 halt();
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81 for (;;)
82 cpu_relax();
72414d3f 83
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84 return 1;
85}
86
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87static void smp_send_nmi_allbutself(void)
88{
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89 cpumask_t mask = cpu_online_map;
90 cpu_clear(safe_smp_processor_id(), mask);
91 if (!cpus_empty(mask))
92 send_IPI_mask(mask, NMI_VECTOR);
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93}
94
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95static struct notifier_block crash_nmi_nb = {
96 .notifier_call = crash_nmi_callback,
97};
98
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99static void nmi_shootdown_cpus(void)
100{
101 unsigned long msecs;
c4ac4263 102
72414d3f 103 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
c4ac4263 104 /* Would it be better to replace the trap vector here? */
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105 if (register_die_notifier(&crash_nmi_nb))
106 return; /* return what? */
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107 /* Ensure the new callback function is set before sending
108 * out the NMI
109 */
110 wmb();
111
112 smp_send_nmi_allbutself();
113
114 msecs = 1000; /* Wait at most a second for the other cpus to stop */
115 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
116 mdelay(1);
117 msecs--;
118 }
119
120 /* Leave the nmi callback set */
19842d67 121 disable_local_APIC();
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122}
123#else
124static void nmi_shootdown_cpus(void)
125{
126 /* There are no cpus to shootdown */
127}
128#endif
129
ed23dc6f 130void native_machine_crash_shutdown(struct pt_regs *regs)
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131{
132 /* This function is only called after the system
f18190bd 133 * has panicked or is otherwise in a critical state.
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134 * The minimum amount of code to allow a kexec'd kernel
135 * to run successfully needs to happen here.
136 *
137 * In practice this means shooting down the other cpus in
138 * an SMP system.
139 */
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140 /* The kernel is broken so disable interrupts */
141 local_irq_disable();
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142
143 /* Make a note of crashing cpu. Will be used in NMI callback.*/
ce53af94 144 crashing_cpu = safe_smp_processor_id();
c4ac4263 145 nmi_shootdown_cpus();
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146 lapic_shutdown();
147#if defined(CONFIG_X86_IO_APIC)
148 disable_IO_APIC();
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149#endif
150#ifdef CONFIG_HPET_TIMER
151 hpet_disable();
19842d67 152#endif
85916f81 153 crash_save_cpu(regs, safe_smp_processor_id());
5033cba0 154}
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