]>
Commit | Line | Data |
---|---|---|
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 | ||
cc532915 ME |
13 | #include <linux/kernel.h> |
14 | #include <linux/smp.h> | |
15 | #include <linux/reboot.h> | |
16 | #include <linux/kexec.h> | |
66b15db6 | 17 | #include <linux/export.h> |
cc532915 | 18 | #include <linux/crash_dump.h> |
cc532915 | 19 | #include <linux/delay.h> |
d6c1a908 | 20 | #include <linux/irq.h> |
cc532915 ME |
21 | #include <linux/types.h> |
22 | ||
23 | #include <asm/processor.h> | |
24 | #include <asm/machdep.h> | |
c0ce7d08 | 25 | #include <asm/kexec.h> |
d9b2b2a2 | 26 | #include <asm/prom.h> |
f6cc82fc | 27 | #include <asm/smp.h> |
496b010e | 28 | #include <asm/setjmp.h> |
ae3a197e | 29 | #include <asm/debug.h> |
cc532915 | 30 | |
549e88a1 AB |
31 | /* |
32 | * The primary CPU waits a while for all secondary CPUs to enter. This is to | |
33 | * avoid sending an IPI if the secondary CPUs are entering | |
34 | * crash_kexec_secondary on their own (eg via a system reset). | |
35 | * | |
36 | * The secondary timeout has to be longer than the primary. Both timeouts are | |
37 | * in milliseconds. | |
38 | */ | |
39 | #define PRIMARY_TIMEOUT 500 | |
40 | #define SECONDARY_TIMEOUT 1000 | |
41 | ||
42 | #define IPI_TIMEOUT 10000 | |
43 | #define REAL_MODE_TIMEOUT 10000 | |
44 | ||
2440c01e | 45 | static int time_to_dump; |
4145f358 BS |
46 | /* |
47 | * crash_wake_offline should be set to 1 by platforms that intend to wake | |
48 | * up offline cpus prior to jumping to a kdump kernel. Currently powernv | |
49 | * sets it to 1, since we want to avoid things from happening when an | |
50 | * offline CPU wakes up due to something like an HMI (malfunction error), | |
51 | * which propagates to all threads. | |
52 | */ | |
53 | int crash_wake_offline; | |
cc532915 | 54 | |
158d5b5e | 55 | #define CRASH_HANDLER_MAX 3 |
1d145165 SJS |
56 | /* List of shutdown handles */ |
57 | static crash_shutdown_t crash_shutdown_handles[CRASH_HANDLER_MAX]; | |
496b010e MN |
58 | static DEFINE_SPINLOCK(crash_handlers_lock); |
59 | ||
07fe0c61 AB |
60 | static unsigned long crash_shutdown_buf[JMP_BUF_LEN]; |
61 | static int crash_shutdown_cpu = -1; | |
62 | ||
63 | static int handle_fault(struct pt_regs *regs) | |
64 | { | |
65 | if (crash_shutdown_cpu == smp_processor_id()) | |
66 | longjmp(crash_shutdown_buf, 1); | |
67 | return 0; | |
68 | } | |
69 | ||
cc532915 | 70 | #ifdef CONFIG_SMP |
cc532915 | 71 | |
897e01a0 | 72 | static atomic_t cpus_in_crash; |
4145f358 | 73 | void crash_ipi_callback(struct pt_regs *regs) |
cc532915 | 74 | { |
2440c01e AB |
75 | static cpumask_t cpus_state_saved = CPU_MASK_NONE; |
76 | ||
cc532915 ME |
77 | int cpu = smp_processor_id(); |
78 | ||
d04c56f7 | 79 | hard_irq_disable(); |
2440c01e | 80 | if (!cpumask_test_cpu(cpu, &cpus_state_saved)) { |
85916f81 | 81 | crash_save_cpu(regs, cpu); |
2440c01e AB |
82 | cpumask_set_cpu(cpu, &cpus_state_saved); |
83 | } | |
84 | ||
85 | atomic_inc(&cpus_in_crash); | |
c645073f | 86 | smp_mb__after_atomic(); |
cc532915 | 87 | |
c0ce7d08 DW |
88 | /* |
89 | * Starting the kdump boot. | |
90 | * This barrier is needed to make sure that all CPUs are stopped. | |
c0ce7d08 | 91 | */ |
2440c01e | 92 | while (!time_to_dump) |
c0ce7d08 DW |
93 | cpu_relax(); |
94 | ||
95 | if (ppc_md.kexec_cpu_down) | |
96 | ppc_md.kexec_cpu_down(1, 1); | |
b6f35b49 ME |
97 | |
98 | #ifdef CONFIG_PPC64 | |
cc532915 | 99 | kexec_smp_wait(); |
b6f35b49 ME |
100 | #else |
101 | for (;;); /* FIXME */ | |
102 | #endif | |
103 | ||
cc532915 ME |
104 | /* NOTREACHED */ |
105 | } | |
106 | ||
c0ce7d08 | 107 | static void crash_kexec_prepare_cpus(int cpu) |
cc532915 ME |
108 | { |
109 | unsigned int msecs; | |
c0ce7d08 | 110 | unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */ |
07fe0c61 AB |
111 | int tries = 0; |
112 | int (*old_handler)(struct pt_regs *regs); | |
cc532915 | 113 | |
9b00ac06 AB |
114 | printk(KERN_EMERG "Sending IPI to other CPUs\n"); |
115 | ||
4145f358 BS |
116 | if (crash_wake_offline) |
117 | ncpus = num_present_cpus() - 1; | |
118 | ||
cc532915 ME |
119 | crash_send_ipi(crash_ipi_callback); |
120 | smp_wmb(); | |
121 | ||
07fe0c61 | 122 | again: |
cc532915 | 123 | /* |
158d5b5e | 124 | * FIXME: Until we will have the way to stop other CPUs reliably, |
cc532915 | 125 | * the crash CPU will send an IPI and wait for other CPUs to |
c0ce7d08 | 126 | * respond. |
cc532915 | 127 | */ |
549e88a1 | 128 | msecs = IPI_TIMEOUT; |
2440c01e | 129 | while ((atomic_read(&cpus_in_crash) < ncpus) && (--msecs > 0)) |
cc532915 | 130 | mdelay(1); |
cc532915 ME |
131 | |
132 | /* Would it be better to replace the trap vector here? */ | |
133 | ||
2440c01e | 134 | if (atomic_read(&cpus_in_crash) >= ncpus) { |
07fe0c61 AB |
135 | printk(KERN_EMERG "IPI complete\n"); |
136 | return; | |
c0ce7d08 | 137 | } |
9b00ac06 | 138 | |
07fe0c61 | 139 | printk(KERN_EMERG "ERROR: %d cpu(s) not responding\n", |
2440c01e | 140 | ncpus - atomic_read(&cpus_in_crash)); |
07fe0c61 AB |
141 | |
142 | /* | |
143 | * If we have a panic timeout set then we can't wait indefinitely | |
144 | * for someone to activate system reset. We also give up on the | |
145 | * second time through if system reset fail to work. | |
146 | */ | |
147 | if ((panic_timeout > 0) || (tries > 0)) | |
148 | return; | |
149 | ||
150 | /* | |
151 | * A system reset will cause all CPUs to take an 0x100 exception. | |
152 | * The primary CPU returns here via setjmp, and the secondary | |
153 | * CPUs reexecute the crash_kexec_secondary path. | |
154 | */ | |
155 | old_handler = __debugger; | |
156 | __debugger = handle_fault; | |
157 | crash_shutdown_cpu = smp_processor_id(); | |
158 | ||
159 | if (setjmp(crash_shutdown_buf) == 0) { | |
160 | printk(KERN_EMERG "Activate system reset (dumprestart) " | |
161 | "to stop other cpu(s)\n"); | |
162 | ||
163 | /* | |
164 | * A system reset will force all CPUs to execute the | |
165 | * crash code again. We need to reset cpus_in_crash so we | |
166 | * wait for everyone to do this. | |
167 | */ | |
2440c01e | 168 | atomic_set(&cpus_in_crash, 0); |
07fe0c61 AB |
169 | smp_mb(); |
170 | ||
2440c01e | 171 | while (atomic_read(&cpus_in_crash) < ncpus) |
07fe0c61 AB |
172 | cpu_relax(); |
173 | } | |
174 | ||
175 | crash_shutdown_cpu = -1; | |
176 | __debugger = old_handler; | |
177 | ||
178 | tries++; | |
179 | goto again; | |
cc532915 | 180 | } |
c0ce7d08 DW |
181 | |
182 | /* | |
9b00ac06 | 183 | * This function will be called by secondary cpus. |
c0ce7d08 DW |
184 | */ |
185 | void crash_kexec_secondary(struct pt_regs *regs) | |
186 | { | |
c0ce7d08 | 187 | unsigned long flags; |
549e88a1 | 188 | int msecs = SECONDARY_TIMEOUT; |
c0ce7d08 DW |
189 | |
190 | local_irq_save(flags); | |
9b00ac06 | 191 | |
549e88a1 | 192 | /* Wait for the primary crash CPU to signal its progress */ |
c0ce7d08 DW |
193 | while (crashing_cpu < 0) { |
194 | if (--msecs < 0) { | |
9b00ac06 | 195 | /* No response, kdump image may not have been loaded */ |
c0ce7d08 DW |
196 | local_irq_restore(flags); |
197 | return; | |
198 | } | |
9b00ac06 | 199 | |
c0ce7d08 | 200 | mdelay(1); |
c0ce7d08 | 201 | } |
9b00ac06 | 202 | |
c0ce7d08 DW |
203 | crash_ipi_callback(regs); |
204 | } | |
205 | ||
7c7a81b5 | 206 | #else /* ! CONFIG_SMP */ |
7c7a81b5 | 207 | |
c0ce7d08 | 208 | static void crash_kexec_prepare_cpus(int cpu) |
cc532915 ME |
209 | { |
210 | /* | |
8c27474a | 211 | * move the secondaries to us so that we can copy |
cc532915 ME |
212 | * the new kernel 0-0x100 safely |
213 | * | |
214 | * do this if kexec in setup.c ? | |
215 | */ | |
b6f35b49 | 216 | #ifdef CONFIG_PPC64 |
cc532915 | 217 | smp_release_cpus(); |
b6f35b49 ME |
218 | #else |
219 | /* FIXME */ | |
220 | #endif | |
cc532915 ME |
221 | } |
222 | ||
c0ce7d08 DW |
223 | void crash_kexec_secondary(struct pt_regs *regs) |
224 | { | |
c0ce7d08 | 225 | } |
7c7a81b5 | 226 | #endif /* CONFIG_SMP */ |
cc532915 | 227 | |
7707e411 | 228 | /* wait for all the CPUs to hit real mode but timeout if they don't come in */ |
eeaab663 SW |
229 | #if defined(CONFIG_SMP) && defined(CONFIG_PPC64) |
230 | static void __maybe_unused crash_kexec_wait_realmode(int cpu) | |
7707e411 BH |
231 | { |
232 | unsigned int msecs; | |
233 | int i; | |
234 | ||
549e88a1 | 235 | msecs = REAL_MODE_TIMEOUT; |
bd9e5eef | 236 | for (i=0; i < nr_cpu_ids && msecs > 0; i++) { |
7707e411 BH |
237 | if (i == cpu) |
238 | continue; | |
239 | ||
d2e60075 | 240 | while (paca_ptrs[i]->kexec_state < KEXEC_STATE_REAL_MODE) { |
7707e411 | 241 | barrier(); |
63f21a56 | 242 | if (!cpu_possible(i) || !cpu_online(i) || (msecs <= 0)) |
7707e411 | 243 | break; |
7707e411 BH |
244 | msecs--; |
245 | mdelay(1); | |
246 | } | |
247 | } | |
248 | mb(); | |
249 | } | |
250 | #else | |
251 | static inline void crash_kexec_wait_realmode(int cpu) {} | |
eeaab663 | 252 | #endif /* CONFIG_SMP && CONFIG_PPC64 */ |
7707e411 | 253 | |
496b010e MN |
254 | /* |
255 | * Register a function to be called on shutdown. Only use this if you | |
256 | * can't reset your device in the second kernel. | |
257 | */ | |
258 | int crash_shutdown_register(crash_shutdown_t handler) | |
259 | { | |
260 | unsigned int i, rc; | |
261 | ||
262 | spin_lock(&crash_handlers_lock); | |
263 | for (i = 0 ; i < CRASH_HANDLER_MAX; i++) | |
264 | if (!crash_shutdown_handles[i]) { | |
265 | /* Insert handle at first empty entry */ | |
266 | crash_shutdown_handles[i] = handler; | |
267 | rc = 0; | |
268 | break; | |
269 | } | |
270 | ||
271 | if (i == CRASH_HANDLER_MAX) { | |
272 | printk(KERN_ERR "Crash shutdown handles full, " | |
273 | "not registered.\n"); | |
274 | rc = 1; | |
275 | } | |
276 | ||
277 | spin_unlock(&crash_handlers_lock); | |
278 | return rc; | |
279 | } | |
280 | EXPORT_SYMBOL(crash_shutdown_register); | |
281 | ||
282 | int crash_shutdown_unregister(crash_shutdown_t handler) | |
283 | { | |
284 | unsigned int i, rc; | |
285 | ||
286 | spin_lock(&crash_handlers_lock); | |
287 | for (i = 0 ; i < CRASH_HANDLER_MAX; i++) | |
288 | if (crash_shutdown_handles[i] == handler) | |
289 | break; | |
290 | ||
291 | if (i == CRASH_HANDLER_MAX) { | |
292 | printk(KERN_ERR "Crash shutdown handle not found\n"); | |
293 | rc = 1; | |
294 | } else { | |
295 | /* Shift handles down */ | |
1d145165 | 296 | for (; i < (CRASH_HANDLER_MAX - 1); i++) |
496b010e MN |
297 | crash_shutdown_handles[i] = |
298 | crash_shutdown_handles[i+1]; | |
1d145165 SJS |
299 | /* |
300 | * Reset last entry to NULL now that it has been shifted down, | |
301 | * this will allow new handles to be added here. | |
302 | */ | |
303 | crash_shutdown_handles[i] = NULL; | |
496b010e MN |
304 | rc = 0; |
305 | } | |
306 | ||
307 | spin_unlock(&crash_handlers_lock); | |
308 | return rc; | |
309 | } | |
310 | EXPORT_SYMBOL(crash_shutdown_unregister); | |
311 | ||
cc532915 ME |
312 | void default_machine_crash_shutdown(struct pt_regs *regs) |
313 | { | |
496b010e MN |
314 | unsigned int i; |
315 | int (*old_handler)(struct pt_regs *regs); | |
316 | ||
cc532915 ME |
317 | /* |
318 | * This function is only called after the system | |
f18190bd | 319 | * has panicked or is otherwise in a critical state. |
cc532915 ME |
320 | * The minimum amount of code to allow a kexec'd kernel |
321 | * to run successfully needs to happen here. | |
322 | * | |
323 | * In practice this means stopping other cpus in | |
324 | * an SMP system. | |
325 | * The kernel is broken so disable interrupts. | |
326 | */ | |
d04c56f7 | 327 | hard_irq_disable(); |
cc532915 | 328 | |
249ec228 AB |
329 | /* |
330 | * Make a note of crashing cpu. Will be used in machine_kexec | |
331 | * such that another IPI will not be sent. | |
332 | */ | |
333 | crashing_cpu = smp_processor_id(); | |
549e88a1 AB |
334 | |
335 | /* | |
336 | * If we came in via system reset, wait a while for the secondary | |
337 | * CPUs to enter. | |
338 | */ | |
339 | if (TRAP(regs) == 0x100) | |
340 | mdelay(PRIMARY_TIMEOUT); | |
341 | ||
249ec228 | 342 | crash_kexec_prepare_cpus(crashing_cpu); |
2440c01e AB |
343 | |
344 | crash_save_cpu(regs, crashing_cpu); | |
345 | ||
346 | time_to_dump = 1; | |
347 | ||
249ec228 | 348 | crash_kexec_wait_realmode(crashing_cpu); |
249ec228 | 349 | |
c71635d2 | 350 | machine_kexec_mask_interrupts(); |
496b010e MN |
351 | |
352 | /* | |
8c27474a | 353 | * Call registered shutdown routines safely. Swap out |
496b010e MN |
354 | * __debugger_fault_handler, and replace on exit. |
355 | */ | |
356 | old_handler = __debugger_fault_handler; | |
357 | __debugger_fault_handler = handle_fault; | |
06440794 | 358 | crash_shutdown_cpu = smp_processor_id(); |
a7d63928 | 359 | for (i = 0; i < CRASH_HANDLER_MAX && crash_shutdown_handles[i]; i++) { |
496b010e MN |
360 | if (setjmp(crash_shutdown_buf) == 0) { |
361 | /* | |
362 | * Insert syncs and delay to ensure | |
363 | * instructions in the dangerous region don't | |
364 | * leak away from this protected region. | |
365 | */ | |
366 | asm volatile("sync; isync"); | |
367 | /* dangerous region */ | |
368 | crash_shutdown_handles[i](); | |
369 | asm volatile("sync; isync"); | |
370 | } | |
d6c1a908 | 371 | } |
06440794 | 372 | crash_shutdown_cpu = -1; |
496b010e | 373 | __debugger_fault_handler = old_handler; |
d6c1a908 | 374 | |
c0ce7d08 DW |
375 | if (ppc_md.kexec_cpu_down) |
376 | ppc_md.kexec_cpu_down(1, 0); | |
cc532915 | 377 | } |