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cc532915 ME |
1 | /* |
2 | * Architecture specific (PPC64) functions for kexec based crash dumps. | |
3 | * | |
4 | * Copyright (C) 2005, IBM Corp. | |
5 | * | |
6 | * Created by: Haren Myneni | |
7 | * | |
8 | * This source code is licensed under the GNU General Public License, | |
9 | * Version 2. See the file COPYING for more details. | |
10 | * | |
11 | */ | |
12 | ||
13 | #undef DEBUG | |
14 | ||
15 | #include <linux/kernel.h> | |
16 | #include <linux/smp.h> | |
17 | #include <linux/reboot.h> | |
18 | #include <linux/kexec.h> | |
19 | #include <linux/bootmem.h> | |
20 | #include <linux/crash_dump.h> | |
cc532915 ME |
21 | #include <linux/delay.h> |
22 | #include <linux/elf.h> | |
23 | #include <linux/elfcore.h> | |
24 | #include <linux/init.h> | |
d6c1a908 | 25 | #include <linux/irq.h> |
cc532915 | 26 | #include <linux/types.h> |
c0ce7d08 | 27 | #include <linux/irq.h> |
cc532915 ME |
28 | |
29 | #include <asm/processor.h> | |
30 | #include <asm/machdep.h> | |
c0ce7d08 | 31 | #include <asm/kexec.h> |
cc532915 ME |
32 | #include <asm/kdump.h> |
33 | #include <asm/lmb.h> | |
34 | #include <asm/firmware.h> | |
f6cc82fc | 35 | #include <asm/smp.h> |
cc532915 ME |
36 | |
37 | #ifdef DEBUG | |
38 | #include <asm/udbg.h> | |
39 | #define DBG(fmt...) udbg_printf(fmt) | |
40 | #else | |
41 | #define DBG(fmt...) | |
42 | #endif | |
43 | ||
44 | /* This keeps a track of which one is crashing cpu. */ | |
45 | int crashing_cpu = -1; | |
c0ce7d08 | 46 | static cpumask_t cpus_in_crash = CPU_MASK_NONE; |
cc532915 ME |
47 | |
48 | static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data, | |
49 | size_t data_len) | |
50 | { | |
51 | struct elf_note note; | |
52 | ||
53 | note.n_namesz = strlen(name) + 1; | |
54 | note.n_descsz = data_len; | |
55 | note.n_type = type; | |
56 | memcpy(buf, ¬e, sizeof(note)); | |
57 | buf += (sizeof(note) +3)/4; | |
58 | memcpy(buf, name, note.n_namesz); | |
59 | buf += (note.n_namesz + 3)/4; | |
60 | memcpy(buf, data, note.n_descsz); | |
61 | buf += (note.n_descsz + 3)/4; | |
62 | ||
63 | return buf; | |
64 | } | |
65 | ||
66 | static void final_note(u32 *buf) | |
67 | { | |
68 | struct elf_note note; | |
69 | ||
70 | note.n_namesz = 0; | |
71 | note.n_descsz = 0; | |
72 | note.n_type = 0; | |
73 | memcpy(buf, ¬e, sizeof(note)); | |
74 | } | |
75 | ||
76 | static void crash_save_this_cpu(struct pt_regs *regs, int cpu) | |
77 | { | |
78 | struct elf_prstatus prstatus; | |
79 | u32 *buf; | |
80 | ||
81 | if ((cpu < 0) || (cpu >= NR_CPUS)) | |
82 | return; | |
83 | ||
84 | /* Using ELF notes here is opportunistic. | |
85 | * I need a well defined structure format | |
86 | * for the data I pass, and I need tags | |
87 | * on the data to indicate what information I have | |
88 | * squirrelled away. ELF notes happen to provide | |
89 | * all of that that no need to invent something new. | |
90 | */ | |
8385a6a3 HM |
91 | buf = (u32*)per_cpu_ptr(crash_notes, cpu); |
92 | if (!buf) | |
93 | return; | |
94 | ||
cc532915 ME |
95 | memset(&prstatus, 0, sizeof(prstatus)); |
96 | prstatus.pr_pid = current->pid; | |
97 | elf_core_copy_regs(&prstatus.pr_reg, regs); | |
98 | buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus, | |
99 | sizeof(prstatus)); | |
100 | final_note(buf); | |
101 | } | |
102 | ||
cc532915 | 103 | #ifdef CONFIG_SMP |
c0ce7d08 | 104 | static atomic_t enter_on_soft_reset = ATOMIC_INIT(0); |
cc532915 ME |
105 | |
106 | void crash_ipi_callback(struct pt_regs *regs) | |
107 | { | |
108 | int cpu = smp_processor_id(); | |
109 | ||
cc532915 ME |
110 | if (!cpu_online(cpu)) |
111 | return; | |
112 | ||
cc532915 | 113 | local_irq_disable(); |
c0ce7d08 DW |
114 | if (!cpu_isset(cpu, cpus_in_crash)) |
115 | crash_save_this_cpu(regs, cpu); | |
116 | cpu_set(cpu, cpus_in_crash); | |
cc532915 | 117 | |
c0ce7d08 DW |
118 | /* |
119 | * Entered via soft-reset - could be the kdump | |
120 | * process is invoked using soft-reset or user activated | |
121 | * it if some CPU did not respond to an IPI. | |
122 | * For soft-reset, the secondary CPU can enter this func | |
123 | * twice. 1 - using IPI, and 2. soft-reset. | |
124 | * Tell the kexec CPU that entered via soft-reset and ready | |
125 | * to go down. | |
126 | */ | |
127 | if (cpu_isset(cpu, cpus_in_sr)) { | |
128 | cpu_clear(cpu, cpus_in_sr); | |
129 | atomic_inc(&enter_on_soft_reset); | |
130 | } | |
131 | ||
132 | /* | |
133 | * Starting the kdump boot. | |
134 | * This barrier is needed to make sure that all CPUs are stopped. | |
135 | * If not, soft-reset will be invoked to bring other CPUs. | |
136 | */ | |
137 | while (!cpu_isset(crashing_cpu, cpus_in_crash)) | |
138 | cpu_relax(); | |
139 | ||
140 | if (ppc_md.kexec_cpu_down) | |
141 | ppc_md.kexec_cpu_down(1, 1); | |
cc532915 ME |
142 | kexec_smp_wait(); |
143 | /* NOTREACHED */ | |
144 | } | |
145 | ||
c0ce7d08 DW |
146 | /* |
147 | * Wait until all CPUs are entered via soft-reset. | |
148 | */ | |
149 | static void crash_soft_reset_check(int cpu) | |
150 | { | |
151 | unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */ | |
152 | ||
153 | cpu_clear(cpu, cpus_in_sr); | |
154 | while (atomic_read(&enter_on_soft_reset) != ncpus) | |
155 | cpu_relax(); | |
156 | } | |
157 | ||
158 | ||
159 | static void crash_kexec_prepare_cpus(int cpu) | |
cc532915 ME |
160 | { |
161 | unsigned int msecs; | |
162 | ||
c0ce7d08 | 163 | unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */ |
cc532915 ME |
164 | |
165 | crash_send_ipi(crash_ipi_callback); | |
166 | smp_wmb(); | |
167 | ||
168 | /* | |
169 | * FIXME: Until we will have the way to stop other CPUSs reliabally, | |
170 | * the crash CPU will send an IPI and wait for other CPUs to | |
c0ce7d08 | 171 | * respond. |
01aaed9d | 172 | * Delay of at least 10 seconds. |
cc532915 | 173 | */ |
c0ce7d08 | 174 | printk(KERN_EMERG "Sending IPI to other cpus...\n"); |
01aaed9d | 175 | msecs = 10000; |
c0ce7d08 DW |
176 | while ((cpus_weight(cpus_in_crash) < ncpus) && (--msecs > 0)) { |
177 | cpu_relax(); | |
cc532915 ME |
178 | mdelay(1); |
179 | } | |
180 | ||
181 | /* Would it be better to replace the trap vector here? */ | |
182 | ||
183 | /* | |
184 | * FIXME: In case if we do not get all CPUs, one possibility: ask the | |
185 | * user to do soft reset such that we get all. | |
c0ce7d08 DW |
186 | * Soft-reset will be used until better mechanism is implemented. |
187 | */ | |
188 | if (cpus_weight(cpus_in_crash) < ncpus) { | |
189 | printk(KERN_EMERG "done waiting: %d cpu(s) not responding\n", | |
190 | ncpus - cpus_weight(cpus_in_crash)); | |
191 | printk(KERN_EMERG "Activate soft-reset to stop other cpu(s)\n"); | |
192 | cpus_in_sr = CPU_MASK_NONE; | |
193 | atomic_set(&enter_on_soft_reset, 0); | |
194 | while (cpus_weight(cpus_in_crash) < ncpus) | |
195 | cpu_relax(); | |
196 | } | |
197 | /* | |
198 | * Make sure all CPUs are entered via soft-reset if the kdump is | |
199 | * invoked using soft-reset. | |
cc532915 | 200 | */ |
c0ce7d08 DW |
201 | if (cpu_isset(cpu, cpus_in_sr)) |
202 | crash_soft_reset_check(cpu); | |
cc532915 ME |
203 | /* Leave the IPI callback set */ |
204 | } | |
c0ce7d08 DW |
205 | |
206 | /* | |
207 | * This function will be called by secondary cpus or by kexec cpu | |
208 | * if soft-reset is activated to stop some CPUs. | |
209 | */ | |
210 | void crash_kexec_secondary(struct pt_regs *regs) | |
211 | { | |
212 | int cpu = smp_processor_id(); | |
213 | unsigned long flags; | |
214 | int msecs = 5; | |
215 | ||
216 | local_irq_save(flags); | |
217 | /* Wait 5ms if the kexec CPU is not entered yet. */ | |
218 | while (crashing_cpu < 0) { | |
219 | if (--msecs < 0) { | |
220 | /* | |
221 | * Either kdump image is not loaded or | |
222 | * kdump process is not started - Probably xmon | |
223 | * exited using 'x'(exit and recover) or | |
224 | * kexec_should_crash() failed for all running tasks. | |
225 | */ | |
226 | cpu_clear(cpu, cpus_in_sr); | |
227 | local_irq_restore(flags); | |
228 | return; | |
229 | } | |
230 | mdelay(1); | |
231 | cpu_relax(); | |
232 | } | |
233 | if (cpu == crashing_cpu) { | |
234 | /* | |
235 | * Panic CPU will enter this func only via soft-reset. | |
236 | * Wait until all secondary CPUs entered and | |
237 | * then start kexec boot. | |
238 | */ | |
239 | crash_soft_reset_check(cpu); | |
240 | cpu_set(crashing_cpu, cpus_in_crash); | |
241 | if (ppc_md.kexec_cpu_down) | |
242 | ppc_md.kexec_cpu_down(1, 0); | |
243 | machine_kexec(kexec_crash_image); | |
244 | /* NOTREACHED */ | |
245 | } | |
246 | crash_ipi_callback(regs); | |
247 | } | |
248 | ||
cc532915 | 249 | #else |
c0ce7d08 | 250 | static void crash_kexec_prepare_cpus(int cpu) |
cc532915 ME |
251 | { |
252 | /* | |
253 | * move the secondarys to us so that we can copy | |
254 | * the new kernel 0-0x100 safely | |
255 | * | |
256 | * do this if kexec in setup.c ? | |
257 | */ | |
258 | smp_release_cpus(); | |
259 | } | |
260 | ||
c0ce7d08 DW |
261 | void crash_kexec_secondary(struct pt_regs *regs) |
262 | { | |
263 | cpus_in_sr = CPU_MASK_NONE; | |
264 | } | |
cc532915 ME |
265 | #endif |
266 | ||
267 | void default_machine_crash_shutdown(struct pt_regs *regs) | |
268 | { | |
d6c1a908 ME |
269 | unsigned int irq; |
270 | ||
cc532915 ME |
271 | /* |
272 | * This function is only called after the system | |
f18190bd | 273 | * has panicked or is otherwise in a critical state. |
cc532915 ME |
274 | * The minimum amount of code to allow a kexec'd kernel |
275 | * to run successfully needs to happen here. | |
276 | * | |
277 | * In practice this means stopping other cpus in | |
278 | * an SMP system. | |
279 | * The kernel is broken so disable interrupts. | |
280 | */ | |
281 | local_irq_disable(); | |
282 | ||
d6c1a908 | 283 | for_each_irq(irq) { |
a8553acd | 284 | struct irq_desc *desc = irq_desc + irq; |
d6c1a908 ME |
285 | |
286 | if (desc->status & IRQ_INPROGRESS) | |
d1bef4ed | 287 | desc->chip->end(irq); |
d6c1a908 ME |
288 | |
289 | if (!(desc->status & IRQ_DISABLED)) | |
d1bef4ed | 290 | desc->chip->disable(irq); |
d6c1a908 ME |
291 | } |
292 | ||
cc532915 ME |
293 | /* |
294 | * Make a note of crashing cpu. Will be used in machine_kexec | |
295 | * such that another IPI will not be sent. | |
296 | */ | |
297 | crashing_cpu = smp_processor_id(); | |
8385a6a3 | 298 | crash_save_this_cpu(regs, crashing_cpu); |
c0ce7d08 DW |
299 | crash_kexec_prepare_cpus(crashing_cpu); |
300 | cpu_set(crashing_cpu, cpus_in_crash); | |
301 | if (ppc_md.kexec_cpu_down) | |
302 | ppc_md.kexec_cpu_down(1, 0); | |
cc532915 | 303 | } |