Commit | Line | Data |
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5033cba0 EB |
1 | /* |
2 | * Architecture specific (i386) 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> | |
5033cba0 EB |
14 | #include <linux/reboot.h> |
15 | #include <linux/kexec.h> | |
5033cba0 EB |
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> |
c4ac4263 | 25 | #include <mach_ipi.h> |
5033cba0 | 26 | |
5033cba0 | 27 | |
a3ea8ac8 VG |
28 | /* This keeps a track of which one is crashing cpu. */ |
29 | static int crashing_cpu; | |
5033cba0 | 30 | |
72414d3f MS |
31 | static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data, |
32 | size_t data_len) | |
2c818b45 EB |
33 | { |
34 | struct elf_note note; | |
72414d3f | 35 | |
2c818b45 EB |
36 | note.n_namesz = strlen(name) + 1; |
37 | note.n_descsz = data_len; | |
38 | note.n_type = type; | |
39 | memcpy(buf, ¬e, sizeof(note)); | |
40 | buf += (sizeof(note) +3)/4; | |
41 | memcpy(buf, name, note.n_namesz); | |
42 | buf += (note.n_namesz + 3)/4; | |
43 | memcpy(buf, data, note.n_descsz); | |
44 | buf += (note.n_descsz + 3)/4; | |
72414d3f | 45 | |
2c818b45 EB |
46 | return buf; |
47 | } | |
48 | ||
49 | static void final_note(u32 *buf) | |
50 | { | |
51 | struct elf_note note; | |
72414d3f | 52 | |
2c818b45 EB |
53 | note.n_namesz = 0; |
54 | note.n_descsz = 0; | |
55 | note.n_type = 0; | |
56 | memcpy(buf, ¬e, sizeof(note)); | |
57 | } | |
58 | ||
2c818b45 EB |
59 | static void crash_save_this_cpu(struct pt_regs *regs, int cpu) |
60 | { | |
61 | struct elf_prstatus prstatus; | |
62 | u32 *buf; | |
72414d3f MS |
63 | |
64 | if ((cpu < 0) || (cpu >= NR_CPUS)) | |
2c818b45 | 65 | return; |
72414d3f | 66 | |
2c818b45 EB |
67 | /* Using ELF notes here is opportunistic. |
68 | * I need a well defined structure format | |
69 | * for the data I pass, and I need tags | |
70 | * on the data to indicate what information I have | |
71 | * squirrelled away. ELF notes happen to provide | |
36a891b6 | 72 | * all of that, so there is no need to invent something new. |
2c818b45 | 73 | */ |
cc571658 VG |
74 | buf = (u32*)per_cpu_ptr(crash_notes, cpu); |
75 | if (!buf) | |
76 | return; | |
2c818b45 EB |
77 | memset(&prstatus, 0, sizeof(prstatus)); |
78 | prstatus.pr_pid = current->pid; | |
79 | elf_core_copy_regs(&prstatus.pr_reg, regs); | |
72414d3f MS |
80 | buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus, |
81 | sizeof(prstatus)); | |
2c818b45 EB |
82 | final_note(buf); |
83 | } | |
84 | ||
e996e581 | 85 | static void crash_save_self(struct pt_regs *regs) |
2c818b45 | 86 | { |
2c818b45 | 87 | int cpu; |
6e274d14 | 88 | |
72414d3f | 89 | cpu = smp_processor_id(); |
e996e581 | 90 | crash_save_this_cpu(regs, cpu); |
2c818b45 EB |
91 | } |
92 | ||
c4ac4263 EB |
93 | #ifdef CONFIG_SMP |
94 | static atomic_t waiting_for_crash_ipi; | |
95 | ||
96 | static int crash_nmi_callback(struct pt_regs *regs, int cpu) | |
97 | { | |
4d55476c | 98 | struct pt_regs fixed_regs; |
a3ea8ac8 VG |
99 | |
100 | /* Don't do anything if this handler is invoked on crashing cpu. | |
101 | * Otherwise, system will completely hang. Crashing cpu can get | |
102 | * an NMI if system was initially booted with nmi_watchdog parameter. | |
103 | */ | |
104 | if (cpu == crashing_cpu) | |
105 | return 1; | |
c4ac4263 | 106 | local_irq_disable(); |
4d55476c | 107 | |
db753bdf | 108 | if (!user_mode_vm(regs)) { |
e996e581 | 109 | crash_fixup_ss_esp(&fixed_regs, regs); |
4d55476c VG |
110 | regs = &fixed_regs; |
111 | } | |
2c818b45 | 112 | crash_save_this_cpu(regs, cpu); |
19842d67 | 113 | disable_local_APIC(); |
c4ac4263 EB |
114 | atomic_dec(&waiting_for_crash_ipi); |
115 | /* Assume hlt works */ | |
f2ab4461 | 116 | halt(); |
caad3c2a CE |
117 | for (;;) |
118 | cpu_relax(); | |
72414d3f | 119 | |
c4ac4263 EB |
120 | return 1; |
121 | } | |
122 | ||
123 | /* | |
124 | * By using the NMI code instead of a vector we just sneak thru the | |
125 | * word generator coming out with just what we want. AND it does | |
126 | * not matter if clustered_apic_mode is set or not. | |
127 | */ | |
128 | static void smp_send_nmi_allbutself(void) | |
129 | { | |
130 | send_IPI_allbutself(APIC_DM_NMI); | |
131 | } | |
132 | ||
133 | static void nmi_shootdown_cpus(void) | |
134 | { | |
135 | unsigned long msecs; | |
c4ac4263 | 136 | |
72414d3f | 137 | atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); |
c4ac4263 EB |
138 | /* Would it be better to replace the trap vector here? */ |
139 | set_nmi_callback(crash_nmi_callback); | |
140 | /* Ensure the new callback function is set before sending | |
141 | * out the NMI | |
142 | */ | |
143 | wmb(); | |
144 | ||
145 | smp_send_nmi_allbutself(); | |
146 | ||
147 | msecs = 1000; /* Wait at most a second for the other cpus to stop */ | |
148 | while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { | |
149 | mdelay(1); | |
150 | msecs--; | |
151 | } | |
152 | ||
153 | /* Leave the nmi callback set */ | |
19842d67 | 154 | disable_local_APIC(); |
c4ac4263 EB |
155 | } |
156 | #else | |
157 | static void nmi_shootdown_cpus(void) | |
158 | { | |
159 | /* There are no cpus to shootdown */ | |
160 | } | |
161 | #endif | |
162 | ||
6e274d14 | 163 | void machine_crash_shutdown(struct pt_regs *regs) |
5033cba0 EB |
164 | { |
165 | /* This function is only called after the system | |
166 | * has paniced or is otherwise in a critical state. | |
167 | * The minimum amount of code to allow a kexec'd kernel | |
168 | * to run successfully needs to happen here. | |
169 | * | |
170 | * In practice this means shooting down the other cpus in | |
171 | * an SMP system. | |
172 | */ | |
c4ac4263 EB |
173 | /* The kernel is broken so disable interrupts */ |
174 | local_irq_disable(); | |
a3ea8ac8 VG |
175 | |
176 | /* Make a note of crashing cpu. Will be used in NMI callback.*/ | |
177 | crashing_cpu = smp_processor_id(); | |
c4ac4263 | 178 | nmi_shootdown_cpus(); |
19842d67 VG |
179 | lapic_shutdown(); |
180 | #if defined(CONFIG_X86_IO_APIC) | |
181 | disable_IO_APIC(); | |
182 | #endif | |
6e274d14 | 183 | crash_save_self(regs); |
5033cba0 | 184 | } |