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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 | ||
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> |
cc532915 | 20 | #include <linux/init.h> |
d6c1a908 | 21 | #include <linux/irq.h> |
cc532915 ME |
22 | #include <linux/types.h> |
23 | ||
24 | #include <asm/processor.h> | |
25 | #include <asm/machdep.h> | |
c0ce7d08 | 26 | #include <asm/kexec.h> |
cc532915 | 27 | #include <asm/kdump.h> |
d9b2b2a2 | 28 | #include <asm/prom.h> |
f6cc82fc | 29 | #include <asm/smp.h> |
496b010e MN |
30 | #include <asm/system.h> |
31 | #include <asm/setjmp.h> | |
cc532915 | 32 | |
549e88a1 AB |
33 | /* |
34 | * The primary CPU waits a while for all secondary CPUs to enter. This is to | |
35 | * avoid sending an IPI if the secondary CPUs are entering | |
36 | * crash_kexec_secondary on their own (eg via a system reset). | |
37 | * | |
38 | * The secondary timeout has to be longer than the primary. Both timeouts are | |
39 | * in milliseconds. | |
40 | */ | |
41 | #define PRIMARY_TIMEOUT 500 | |
42 | #define SECONDARY_TIMEOUT 1000 | |
43 | ||
44 | #define IPI_TIMEOUT 10000 | |
45 | #define REAL_MODE_TIMEOUT 10000 | |
46 | ||
8c27474a | 47 | /* This keeps a track of which one is the crashing cpu. */ |
cc532915 | 48 | int crashing_cpu = -1; |
2440c01e AB |
49 | static atomic_t cpus_in_crash; |
50 | static int time_to_dump; | |
cc532915 | 51 | |
158d5b5e | 52 | #define CRASH_HANDLER_MAX 3 |
496b010e MN |
53 | /* NULL terminated list of shutdown handles */ |
54 | static crash_shutdown_t crash_shutdown_handles[CRASH_HANDLER_MAX+1]; | |
55 | static DEFINE_SPINLOCK(crash_handlers_lock); | |
56 | ||
07fe0c61 AB |
57 | static unsigned long crash_shutdown_buf[JMP_BUF_LEN]; |
58 | static int crash_shutdown_cpu = -1; | |
59 | ||
60 | static int handle_fault(struct pt_regs *regs) | |
61 | { | |
62 | if (crash_shutdown_cpu == smp_processor_id()) | |
63 | longjmp(crash_shutdown_buf, 1); | |
64 | return 0; | |
65 | } | |
66 | ||
cc532915 | 67 | #ifdef CONFIG_SMP |
cc532915 ME |
68 | |
69 | void crash_ipi_callback(struct pt_regs *regs) | |
70 | { | |
2440c01e AB |
71 | static cpumask_t cpus_state_saved = CPU_MASK_NONE; |
72 | ||
cc532915 ME |
73 | int cpu = smp_processor_id(); |
74 | ||
cc532915 ME |
75 | if (!cpu_online(cpu)) |
76 | return; | |
77 | ||
d04c56f7 | 78 | hard_irq_disable(); |
2440c01e | 79 | if (!cpumask_test_cpu(cpu, &cpus_state_saved)) { |
85916f81 | 80 | crash_save_cpu(regs, cpu); |
2440c01e AB |
81 | cpumask_set_cpu(cpu, &cpus_state_saved); |
82 | } | |
83 | ||
84 | atomic_inc(&cpus_in_crash); | |
85 | smp_mb__after_atomic_inc(); | |
cc532915 | 86 | |
c0ce7d08 DW |
87 | /* |
88 | * Starting the kdump boot. | |
89 | * This barrier is needed to make sure that all CPUs are stopped. | |
c0ce7d08 | 90 | */ |
2440c01e | 91 | while (!time_to_dump) |
c0ce7d08 DW |
92 | cpu_relax(); |
93 | ||
94 | if (ppc_md.kexec_cpu_down) | |
95 | ppc_md.kexec_cpu_down(1, 1); | |
b6f35b49 ME |
96 | |
97 | #ifdef CONFIG_PPC64 | |
cc532915 | 98 | kexec_smp_wait(); |
b6f35b49 ME |
99 | #else |
100 | for (;;); /* FIXME */ | |
101 | #endif | |
102 | ||
cc532915 ME |
103 | /* NOTREACHED */ |
104 | } | |
105 | ||
c0ce7d08 | 106 | static void crash_kexec_prepare_cpus(int cpu) |
cc532915 ME |
107 | { |
108 | unsigned int msecs; | |
c0ce7d08 | 109 | unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */ |
07fe0c61 AB |
110 | int tries = 0; |
111 | int (*old_handler)(struct pt_regs *regs); | |
cc532915 | 112 | |
9b00ac06 AB |
113 | printk(KERN_EMERG "Sending IPI to other CPUs\n"); |
114 | ||
cc532915 ME |
115 | crash_send_ipi(crash_ipi_callback); |
116 | smp_wmb(); | |
117 | ||
07fe0c61 | 118 | again: |
cc532915 | 119 | /* |
158d5b5e | 120 | * FIXME: Until we will have the way to stop other CPUs reliably, |
cc532915 | 121 | * the crash CPU will send an IPI and wait for other CPUs to |
c0ce7d08 | 122 | * respond. |
cc532915 | 123 | */ |
549e88a1 | 124 | msecs = IPI_TIMEOUT; |
2440c01e | 125 | while ((atomic_read(&cpus_in_crash) < ncpus) && (--msecs > 0)) |
cc532915 | 126 | mdelay(1); |
cc532915 ME |
127 | |
128 | /* Would it be better to replace the trap vector here? */ | |
129 | ||
2440c01e | 130 | if (atomic_read(&cpus_in_crash) >= ncpus) { |
07fe0c61 AB |
131 | printk(KERN_EMERG "IPI complete\n"); |
132 | return; | |
c0ce7d08 | 133 | } |
9b00ac06 | 134 | |
07fe0c61 | 135 | printk(KERN_EMERG "ERROR: %d cpu(s) not responding\n", |
2440c01e | 136 | ncpus - atomic_read(&cpus_in_crash)); |
07fe0c61 AB |
137 | |
138 | /* | |
139 | * If we have a panic timeout set then we can't wait indefinitely | |
140 | * for someone to activate system reset. We also give up on the | |
141 | * second time through if system reset fail to work. | |
142 | */ | |
143 | if ((panic_timeout > 0) || (tries > 0)) | |
144 | return; | |
145 | ||
146 | /* | |
147 | * A system reset will cause all CPUs to take an 0x100 exception. | |
148 | * The primary CPU returns here via setjmp, and the secondary | |
149 | * CPUs reexecute the crash_kexec_secondary path. | |
150 | */ | |
151 | old_handler = __debugger; | |
152 | __debugger = handle_fault; | |
153 | crash_shutdown_cpu = smp_processor_id(); | |
154 | ||
155 | if (setjmp(crash_shutdown_buf) == 0) { | |
156 | printk(KERN_EMERG "Activate system reset (dumprestart) " | |
157 | "to stop other cpu(s)\n"); | |
158 | ||
159 | /* | |
160 | * A system reset will force all CPUs to execute the | |
161 | * crash code again. We need to reset cpus_in_crash so we | |
162 | * wait for everyone to do this. | |
163 | */ | |
2440c01e | 164 | atomic_set(&cpus_in_crash, 0); |
07fe0c61 AB |
165 | smp_mb(); |
166 | ||
2440c01e | 167 | while (atomic_read(&cpus_in_crash) < ncpus) |
07fe0c61 AB |
168 | cpu_relax(); |
169 | } | |
170 | ||
171 | crash_shutdown_cpu = -1; | |
172 | __debugger = old_handler; | |
173 | ||
174 | tries++; | |
175 | goto again; | |
cc532915 | 176 | } |
c0ce7d08 DW |
177 | |
178 | /* | |
9b00ac06 | 179 | * This function will be called by secondary cpus. |
c0ce7d08 DW |
180 | */ |
181 | void crash_kexec_secondary(struct pt_regs *regs) | |
182 | { | |
c0ce7d08 | 183 | unsigned long flags; |
549e88a1 | 184 | int msecs = SECONDARY_TIMEOUT; |
c0ce7d08 DW |
185 | |
186 | local_irq_save(flags); | |
9b00ac06 | 187 | |
549e88a1 | 188 | /* Wait for the primary crash CPU to signal its progress */ |
c0ce7d08 DW |
189 | while (crashing_cpu < 0) { |
190 | if (--msecs < 0) { | |
9b00ac06 | 191 | /* No response, kdump image may not have been loaded */ |
c0ce7d08 DW |
192 | local_irq_restore(flags); |
193 | return; | |
194 | } | |
9b00ac06 | 195 | |
c0ce7d08 | 196 | mdelay(1); |
c0ce7d08 | 197 | } |
9b00ac06 | 198 | |
c0ce7d08 DW |
199 | crash_ipi_callback(regs); |
200 | } | |
201 | ||
7c7a81b5 | 202 | #else /* ! CONFIG_SMP */ |
7c7a81b5 | 203 | |
c0ce7d08 | 204 | static void crash_kexec_prepare_cpus(int cpu) |
cc532915 ME |
205 | { |
206 | /* | |
8c27474a | 207 | * move the secondaries to us so that we can copy |
cc532915 ME |
208 | * the new kernel 0-0x100 safely |
209 | * | |
210 | * do this if kexec in setup.c ? | |
211 | */ | |
b6f35b49 | 212 | #ifdef CONFIG_PPC64 |
cc532915 | 213 | smp_release_cpus(); |
b6f35b49 ME |
214 | #else |
215 | /* FIXME */ | |
216 | #endif | |
cc532915 ME |
217 | } |
218 | ||
c0ce7d08 DW |
219 | void crash_kexec_secondary(struct pt_regs *regs) |
220 | { | |
c0ce7d08 | 221 | } |
7c7a81b5 | 222 | #endif /* CONFIG_SMP */ |
cc532915 | 223 | |
7707e411 BH |
224 | /* wait for all the CPUs to hit real mode but timeout if they don't come in */ |
225 | #if defined(CONFIG_SMP) && defined(CONFIG_PPC_STD_MMU_64) | |
226 | static void crash_kexec_wait_realmode(int cpu) | |
227 | { | |
228 | unsigned int msecs; | |
229 | int i; | |
230 | ||
549e88a1 | 231 | msecs = REAL_MODE_TIMEOUT; |
bd9e5eef | 232 | for (i=0; i < nr_cpu_ids && msecs > 0; i++) { |
7707e411 BH |
233 | if (i == cpu) |
234 | continue; | |
235 | ||
236 | while (paca[i].kexec_state < KEXEC_STATE_REAL_MODE) { | |
237 | barrier(); | |
63f21a56 | 238 | if (!cpu_possible(i) || !cpu_online(i) || (msecs <= 0)) |
7707e411 | 239 | break; |
7707e411 BH |
240 | msecs--; |
241 | mdelay(1); | |
242 | } | |
243 | } | |
244 | mb(); | |
245 | } | |
246 | #else | |
247 | static inline void crash_kexec_wait_realmode(int cpu) {} | |
248 | #endif /* CONFIG_SMP && CONFIG_PPC_STD_MMU_64 */ | |
249 | ||
496b010e MN |
250 | /* |
251 | * Register a function to be called on shutdown. Only use this if you | |
252 | * can't reset your device in the second kernel. | |
253 | */ | |
254 | int crash_shutdown_register(crash_shutdown_t handler) | |
255 | { | |
256 | unsigned int i, rc; | |
257 | ||
258 | spin_lock(&crash_handlers_lock); | |
259 | for (i = 0 ; i < CRASH_HANDLER_MAX; i++) | |
260 | if (!crash_shutdown_handles[i]) { | |
261 | /* Insert handle at first empty entry */ | |
262 | crash_shutdown_handles[i] = handler; | |
263 | rc = 0; | |
264 | break; | |
265 | } | |
266 | ||
267 | if (i == CRASH_HANDLER_MAX) { | |
268 | printk(KERN_ERR "Crash shutdown handles full, " | |
269 | "not registered.\n"); | |
270 | rc = 1; | |
271 | } | |
272 | ||
273 | spin_unlock(&crash_handlers_lock); | |
274 | return rc; | |
275 | } | |
276 | EXPORT_SYMBOL(crash_shutdown_register); | |
277 | ||
278 | int crash_shutdown_unregister(crash_shutdown_t handler) | |
279 | { | |
280 | unsigned int i, rc; | |
281 | ||
282 | spin_lock(&crash_handlers_lock); | |
283 | for (i = 0 ; i < CRASH_HANDLER_MAX; i++) | |
284 | if (crash_shutdown_handles[i] == handler) | |
285 | break; | |
286 | ||
287 | if (i == CRASH_HANDLER_MAX) { | |
288 | printk(KERN_ERR "Crash shutdown handle not found\n"); | |
289 | rc = 1; | |
290 | } else { | |
291 | /* Shift handles down */ | |
292 | for (; crash_shutdown_handles[i]; i++) | |
293 | crash_shutdown_handles[i] = | |
294 | crash_shutdown_handles[i+1]; | |
295 | rc = 0; | |
296 | } | |
297 | ||
298 | spin_unlock(&crash_handlers_lock); | |
299 | return rc; | |
300 | } | |
301 | EXPORT_SYMBOL(crash_shutdown_unregister); | |
302 | ||
cc532915 ME |
303 | void default_machine_crash_shutdown(struct pt_regs *regs) |
304 | { | |
496b010e MN |
305 | unsigned int i; |
306 | int (*old_handler)(struct pt_regs *regs); | |
307 | ||
cc532915 ME |
308 | /* |
309 | * This function is only called after the system | |
f18190bd | 310 | * has panicked or is otherwise in a critical state. |
cc532915 ME |
311 | * The minimum amount of code to allow a kexec'd kernel |
312 | * to run successfully needs to happen here. | |
313 | * | |
314 | * In practice this means stopping other cpus in | |
315 | * an SMP system. | |
316 | * The kernel is broken so disable interrupts. | |
317 | */ | |
d04c56f7 | 318 | hard_irq_disable(); |
cc532915 | 319 | |
249ec228 AB |
320 | /* |
321 | * Make a note of crashing cpu. Will be used in machine_kexec | |
322 | * such that another IPI will not be sent. | |
323 | */ | |
324 | crashing_cpu = smp_processor_id(); | |
549e88a1 AB |
325 | |
326 | /* | |
327 | * If we came in via system reset, wait a while for the secondary | |
328 | * CPUs to enter. | |
329 | */ | |
330 | if (TRAP(regs) == 0x100) | |
331 | mdelay(PRIMARY_TIMEOUT); | |
332 | ||
249ec228 | 333 | crash_kexec_prepare_cpus(crashing_cpu); |
2440c01e AB |
334 | |
335 | crash_save_cpu(regs, crashing_cpu); | |
336 | ||
337 | time_to_dump = 1; | |
338 | ||
249ec228 | 339 | crash_kexec_wait_realmode(crashing_cpu); |
249ec228 | 340 | |
c71635d2 | 341 | machine_kexec_mask_interrupts(); |
496b010e MN |
342 | |
343 | /* | |
8c27474a | 344 | * Call registered shutdown routines safely. Swap out |
496b010e MN |
345 | * __debugger_fault_handler, and replace on exit. |
346 | */ | |
347 | old_handler = __debugger_fault_handler; | |
348 | __debugger_fault_handler = handle_fault; | |
06440794 | 349 | crash_shutdown_cpu = smp_processor_id(); |
496b010e MN |
350 | for (i = 0; crash_shutdown_handles[i]; i++) { |
351 | if (setjmp(crash_shutdown_buf) == 0) { | |
352 | /* | |
353 | * Insert syncs and delay to ensure | |
354 | * instructions in the dangerous region don't | |
355 | * leak away from this protected region. | |
356 | */ | |
357 | asm volatile("sync; isync"); | |
358 | /* dangerous region */ | |
359 | crash_shutdown_handles[i](); | |
360 | asm volatile("sync; isync"); | |
361 | } | |
d6c1a908 | 362 | } |
06440794 | 363 | crash_shutdown_cpu = -1; |
496b010e | 364 | __debugger_fault_handler = old_handler; |
d6c1a908 | 365 | |
c0ce7d08 DW |
366 | if (ppc_md.kexec_cpu_down) |
367 | ppc_md.kexec_cpu_down(1, 0); | |
cc532915 | 368 | } |