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1da177e4 LT |
1 | /* |
2 | * linux/arch/i386/nmi.c | |
3 | * | |
4 | * NMI watchdog support on APIC systems | |
5 | * | |
6 | * Started by Ingo Molnar <mingo@redhat.com> | |
7 | * | |
8 | * Fixes: | |
9 | * Mikael Pettersson : AMD K7 support for local APIC NMI watchdog. | |
10 | * Mikael Pettersson : Power Management for local APIC NMI watchdog. | |
11 | * Mikael Pettersson : Pentium 4 support for local APIC NMI watchdog. | |
12 | * Pavel Machek and | |
13 | * Mikael Pettersson : PM converted to driver model. Disable/enable API. | |
14 | */ | |
15 | ||
16 | #include <linux/config.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/irq.h> | |
19 | #include <linux/delay.h> | |
20 | #include <linux/bootmem.h> | |
21 | #include <linux/smp_lock.h> | |
22 | #include <linux/interrupt.h> | |
23 | #include <linux/mc146818rtc.h> | |
24 | #include <linux/kernel_stat.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/nmi.h> | |
27 | #include <linux/sysdev.h> | |
28 | #include <linux/sysctl.h> | |
29 | ||
30 | #include <asm/smp.h> | |
7fbb4f6e | 31 | #include <asm/div64.h> |
1da177e4 LT |
32 | #include <asm/nmi.h> |
33 | ||
34 | #include "mach_traps.h" | |
35 | ||
36 | unsigned int nmi_watchdog = NMI_NONE; | |
37 | extern int unknown_nmi_panic; | |
38 | static unsigned int nmi_hz = HZ; | |
39 | static unsigned int nmi_perfctr_msr; /* the MSR to reset in NMI handler */ | |
40 | static unsigned int nmi_p4_cccr_val; | |
41 | extern void show_registers(struct pt_regs *regs); | |
42 | ||
43 | /* | |
44 | * lapic_nmi_owner tracks the ownership of the lapic NMI hardware: | |
45 | * - it may be reserved by some other driver, or not | |
46 | * - when not reserved by some other driver, it may be used for | |
47 | * the NMI watchdog, or not | |
48 | * | |
49 | * This is maintained separately from nmi_active because the NMI | |
50 | * watchdog may also be driven from the I/O APIC timer. | |
51 | */ | |
52 | static DEFINE_SPINLOCK(lapic_nmi_owner_lock); | |
53 | static unsigned int lapic_nmi_owner; | |
54 | #define LAPIC_NMI_WATCHDOG (1<<0) | |
55 | #define LAPIC_NMI_RESERVED (1<<1) | |
56 | ||
57 | /* nmi_active: | |
58 | * +1: the lapic NMI watchdog is active, but can be disabled | |
59 | * 0: the lapic NMI watchdog has not been set up, and cannot | |
60 | * be enabled | |
61 | * -1: the lapic NMI watchdog is disabled, but can be enabled | |
62 | */ | |
63 | int nmi_active; | |
64 | ||
65 | #define K7_EVNTSEL_ENABLE (1 << 22) | |
66 | #define K7_EVNTSEL_INT (1 << 20) | |
67 | #define K7_EVNTSEL_OS (1 << 17) | |
68 | #define K7_EVNTSEL_USR (1 << 16) | |
69 | #define K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING 0x76 | |
70 | #define K7_NMI_EVENT K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING | |
71 | ||
72 | #define P6_EVNTSEL0_ENABLE (1 << 22) | |
73 | #define P6_EVNTSEL_INT (1 << 20) | |
74 | #define P6_EVNTSEL_OS (1 << 17) | |
75 | #define P6_EVNTSEL_USR (1 << 16) | |
76 | #define P6_EVENT_CPU_CLOCKS_NOT_HALTED 0x79 | |
77 | #define P6_NMI_EVENT P6_EVENT_CPU_CLOCKS_NOT_HALTED | |
78 | ||
79 | #define MSR_P4_MISC_ENABLE 0x1A0 | |
80 | #define MSR_P4_MISC_ENABLE_PERF_AVAIL (1<<7) | |
81 | #define MSR_P4_MISC_ENABLE_PEBS_UNAVAIL (1<<12) | |
82 | #define MSR_P4_PERFCTR0 0x300 | |
83 | #define MSR_P4_CCCR0 0x360 | |
84 | #define P4_ESCR_EVENT_SELECT(N) ((N)<<25) | |
85 | #define P4_ESCR_OS (1<<3) | |
86 | #define P4_ESCR_USR (1<<2) | |
87 | #define P4_CCCR_OVF_PMI0 (1<<26) | |
88 | #define P4_CCCR_OVF_PMI1 (1<<27) | |
89 | #define P4_CCCR_THRESHOLD(N) ((N)<<20) | |
90 | #define P4_CCCR_COMPLEMENT (1<<19) | |
91 | #define P4_CCCR_COMPARE (1<<18) | |
92 | #define P4_CCCR_REQUIRED (3<<16) | |
93 | #define P4_CCCR_ESCR_SELECT(N) ((N)<<13) | |
94 | #define P4_CCCR_ENABLE (1<<12) | |
95 | /* Set up IQ_COUNTER0 to behave like a clock, by having IQ_CCCR0 filter | |
96 | CRU_ESCR0 (with any non-null event selector) through a complemented | |
97 | max threshold. [IA32-Vol3, Section 14.9.9] */ | |
98 | #define MSR_P4_IQ_COUNTER0 0x30C | |
99 | #define P4_NMI_CRU_ESCR0 (P4_ESCR_EVENT_SELECT(0x3F)|P4_ESCR_OS|P4_ESCR_USR) | |
100 | #define P4_NMI_IQ_CCCR0 \ | |
101 | (P4_CCCR_OVF_PMI0|P4_CCCR_THRESHOLD(15)|P4_CCCR_COMPLEMENT| \ | |
102 | P4_CCCR_COMPARE|P4_CCCR_REQUIRED|P4_CCCR_ESCR_SELECT(4)|P4_CCCR_ENABLE) | |
103 | ||
67701ae9 | 104 | static int __init check_nmi_watchdog(void) |
1da177e4 LT |
105 | { |
106 | unsigned int prev_nmi_count[NR_CPUS]; | |
107 | int cpu; | |
108 | ||
67701ae9 JV |
109 | if (nmi_watchdog == NMI_NONE) |
110 | return 0; | |
111 | ||
112 | printk(KERN_INFO "Testing NMI watchdog ... "); | |
1da177e4 LT |
113 | |
114 | for (cpu = 0; cpu < NR_CPUS; cpu++) | |
115 | prev_nmi_count[cpu] = per_cpu(irq_stat, cpu).__nmi_count; | |
116 | local_irq_enable(); | |
117 | mdelay((10*1000)/nmi_hz); // wait 10 ticks | |
118 | ||
1da177e4 LT |
119 | for (cpu = 0; cpu < NR_CPUS; cpu++) { |
120 | #ifdef CONFIG_SMP | |
121 | /* Check cpu_callin_map here because that is set | |
122 | after the timer is started. */ | |
123 | if (!cpu_isset(cpu, cpu_callin_map)) | |
124 | continue; | |
125 | #endif | |
126 | if (nmi_count(cpu) - prev_nmi_count[cpu] <= 5) { | |
127 | printk("CPU#%d: NMI appears to be stuck!\n", cpu); | |
128 | nmi_active = 0; | |
129 | lapic_nmi_owner &= ~LAPIC_NMI_WATCHDOG; | |
130 | return -1; | |
131 | } | |
132 | } | |
133 | printk("OK.\n"); | |
134 | ||
135 | /* now that we know it works we can reduce NMI frequency to | |
136 | something more reasonable; makes a difference in some configs */ | |
137 | if (nmi_watchdog == NMI_LOCAL_APIC) | |
138 | nmi_hz = 1; | |
139 | ||
140 | return 0; | |
141 | } | |
67701ae9 JV |
142 | /* This needs to happen later in boot so counters are working */ |
143 | late_initcall(check_nmi_watchdog); | |
1da177e4 LT |
144 | |
145 | static int __init setup_nmi_watchdog(char *str) | |
146 | { | |
147 | int nmi; | |
148 | ||
149 | get_option(&str, &nmi); | |
150 | ||
151 | if (nmi >= NMI_INVALID) | |
152 | return 0; | |
153 | if (nmi == NMI_NONE) | |
154 | nmi_watchdog = nmi; | |
155 | /* | |
156 | * If any other x86 CPU has a local APIC, then | |
157 | * please test the NMI stuff there and send me the | |
158 | * missing bits. Right now Intel P6/P4 and AMD K7 only. | |
159 | */ | |
160 | if ((nmi == NMI_LOCAL_APIC) && | |
161 | (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && | |
162 | (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15)) | |
163 | nmi_watchdog = nmi; | |
164 | if ((nmi == NMI_LOCAL_APIC) && | |
165 | (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && | |
166 | (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15)) | |
167 | nmi_watchdog = nmi; | |
168 | /* | |
169 | * We can enable the IO-APIC watchdog | |
170 | * unconditionally. | |
171 | */ | |
172 | if (nmi == NMI_IO_APIC) { | |
173 | nmi_active = 1; | |
174 | nmi_watchdog = nmi; | |
175 | } | |
176 | return 1; | |
177 | } | |
178 | ||
179 | __setup("nmi_watchdog=", setup_nmi_watchdog); | |
180 | ||
181 | static void disable_lapic_nmi_watchdog(void) | |
182 | { | |
183 | if (nmi_active <= 0) | |
184 | return; | |
185 | switch (boot_cpu_data.x86_vendor) { | |
186 | case X86_VENDOR_AMD: | |
187 | wrmsr(MSR_K7_EVNTSEL0, 0, 0); | |
188 | break; | |
189 | case X86_VENDOR_INTEL: | |
190 | switch (boot_cpu_data.x86) { | |
191 | case 6: | |
192 | if (boot_cpu_data.x86_model > 0xd) | |
193 | break; | |
194 | ||
195 | wrmsr(MSR_P6_EVNTSEL0, 0, 0); | |
196 | break; | |
197 | case 15: | |
198 | if (boot_cpu_data.x86_model > 0x3) | |
199 | break; | |
200 | ||
201 | wrmsr(MSR_P4_IQ_CCCR0, 0, 0); | |
202 | wrmsr(MSR_P4_CRU_ESCR0, 0, 0); | |
203 | break; | |
204 | } | |
205 | break; | |
206 | } | |
207 | nmi_active = -1; | |
208 | /* tell do_nmi() and others that we're not active any more */ | |
209 | nmi_watchdog = 0; | |
210 | } | |
211 | ||
212 | static void enable_lapic_nmi_watchdog(void) | |
213 | { | |
214 | if (nmi_active < 0) { | |
215 | nmi_watchdog = NMI_LOCAL_APIC; | |
216 | setup_apic_nmi_watchdog(); | |
217 | } | |
218 | } | |
219 | ||
220 | int reserve_lapic_nmi(void) | |
221 | { | |
222 | unsigned int old_owner; | |
223 | ||
224 | spin_lock(&lapic_nmi_owner_lock); | |
225 | old_owner = lapic_nmi_owner; | |
226 | lapic_nmi_owner |= LAPIC_NMI_RESERVED; | |
227 | spin_unlock(&lapic_nmi_owner_lock); | |
228 | if (old_owner & LAPIC_NMI_RESERVED) | |
229 | return -EBUSY; | |
230 | if (old_owner & LAPIC_NMI_WATCHDOG) | |
231 | disable_lapic_nmi_watchdog(); | |
232 | return 0; | |
233 | } | |
234 | ||
235 | void release_lapic_nmi(void) | |
236 | { | |
237 | unsigned int new_owner; | |
238 | ||
239 | spin_lock(&lapic_nmi_owner_lock); | |
240 | new_owner = lapic_nmi_owner & ~LAPIC_NMI_RESERVED; | |
241 | lapic_nmi_owner = new_owner; | |
242 | spin_unlock(&lapic_nmi_owner_lock); | |
243 | if (new_owner & LAPIC_NMI_WATCHDOG) | |
244 | enable_lapic_nmi_watchdog(); | |
245 | } | |
246 | ||
247 | void disable_timer_nmi_watchdog(void) | |
248 | { | |
249 | if ((nmi_watchdog != NMI_IO_APIC) || (nmi_active <= 0)) | |
250 | return; | |
251 | ||
252 | unset_nmi_callback(); | |
253 | nmi_active = -1; | |
254 | nmi_watchdog = NMI_NONE; | |
255 | } | |
256 | ||
257 | void enable_timer_nmi_watchdog(void) | |
258 | { | |
259 | if (nmi_active < 0) { | |
260 | nmi_watchdog = NMI_IO_APIC; | |
261 | touch_nmi_watchdog(); | |
262 | nmi_active = 1; | |
263 | } | |
264 | } | |
265 | ||
266 | #ifdef CONFIG_PM | |
267 | ||
268 | static int nmi_pm_active; /* nmi_active before suspend */ | |
269 | ||
438510f6 | 270 | static int lapic_nmi_suspend(struct sys_device *dev, pm_message_t state) |
1da177e4 LT |
271 | { |
272 | nmi_pm_active = nmi_active; | |
273 | disable_lapic_nmi_watchdog(); | |
274 | return 0; | |
275 | } | |
276 | ||
277 | static int lapic_nmi_resume(struct sys_device *dev) | |
278 | { | |
279 | if (nmi_pm_active > 0) | |
280 | enable_lapic_nmi_watchdog(); | |
281 | return 0; | |
282 | } | |
283 | ||
284 | ||
285 | static struct sysdev_class nmi_sysclass = { | |
286 | set_kset_name("lapic_nmi"), | |
287 | .resume = lapic_nmi_resume, | |
288 | .suspend = lapic_nmi_suspend, | |
289 | }; | |
290 | ||
291 | static struct sys_device device_lapic_nmi = { | |
292 | .id = 0, | |
293 | .cls = &nmi_sysclass, | |
294 | }; | |
295 | ||
296 | static int __init init_lapic_nmi_sysfs(void) | |
297 | { | |
298 | int error; | |
299 | ||
300 | if (nmi_active == 0 || nmi_watchdog != NMI_LOCAL_APIC) | |
301 | return 0; | |
302 | ||
303 | error = sysdev_class_register(&nmi_sysclass); | |
304 | if (!error) | |
305 | error = sysdev_register(&device_lapic_nmi); | |
306 | return error; | |
307 | } | |
308 | /* must come after the local APIC's device_initcall() */ | |
309 | late_initcall(init_lapic_nmi_sysfs); | |
310 | ||
311 | #endif /* CONFIG_PM */ | |
312 | ||
313 | /* | |
314 | * Activate the NMI watchdog via the local APIC. | |
315 | * Original code written by Keith Owens. | |
316 | */ | |
317 | ||
318 | static void clear_msr_range(unsigned int base, unsigned int n) | |
319 | { | |
320 | unsigned int i; | |
321 | ||
322 | for(i = 0; i < n; ++i) | |
323 | wrmsr(base+i, 0, 0); | |
324 | } | |
325 | ||
7fbb4f6e JB |
326 | static inline void write_watchdog_counter(const char *descr) |
327 | { | |
328 | u64 count = (u64)cpu_khz * 1000; | |
329 | ||
330 | do_div(count, nmi_hz); | |
331 | if(descr) | |
332 | Dprintk("setting %s to -0x%08Lx\n", descr, count); | |
333 | wrmsrl(nmi_perfctr_msr, 0 - count); | |
334 | } | |
335 | ||
1da177e4 LT |
336 | static void setup_k7_watchdog(void) |
337 | { | |
338 | unsigned int evntsel; | |
339 | ||
340 | nmi_perfctr_msr = MSR_K7_PERFCTR0; | |
341 | ||
342 | clear_msr_range(MSR_K7_EVNTSEL0, 4); | |
343 | clear_msr_range(MSR_K7_PERFCTR0, 4); | |
344 | ||
345 | evntsel = K7_EVNTSEL_INT | |
346 | | K7_EVNTSEL_OS | |
347 | | K7_EVNTSEL_USR | |
348 | | K7_NMI_EVENT; | |
349 | ||
350 | wrmsr(MSR_K7_EVNTSEL0, evntsel, 0); | |
7fbb4f6e | 351 | write_watchdog_counter("K7_PERFCTR0"); |
1da177e4 LT |
352 | apic_write(APIC_LVTPC, APIC_DM_NMI); |
353 | evntsel |= K7_EVNTSEL_ENABLE; | |
354 | wrmsr(MSR_K7_EVNTSEL0, evntsel, 0); | |
355 | } | |
356 | ||
357 | static void setup_p6_watchdog(void) | |
358 | { | |
359 | unsigned int evntsel; | |
360 | ||
361 | nmi_perfctr_msr = MSR_P6_PERFCTR0; | |
362 | ||
363 | clear_msr_range(MSR_P6_EVNTSEL0, 2); | |
364 | clear_msr_range(MSR_P6_PERFCTR0, 2); | |
365 | ||
366 | evntsel = P6_EVNTSEL_INT | |
367 | | P6_EVNTSEL_OS | |
368 | | P6_EVNTSEL_USR | |
369 | | P6_NMI_EVENT; | |
370 | ||
371 | wrmsr(MSR_P6_EVNTSEL0, evntsel, 0); | |
7fbb4f6e | 372 | write_watchdog_counter("P6_PERFCTR0"); |
1da177e4 LT |
373 | apic_write(APIC_LVTPC, APIC_DM_NMI); |
374 | evntsel |= P6_EVNTSEL0_ENABLE; | |
375 | wrmsr(MSR_P6_EVNTSEL0, evntsel, 0); | |
376 | } | |
377 | ||
378 | static int setup_p4_watchdog(void) | |
379 | { | |
380 | unsigned int misc_enable, dummy; | |
381 | ||
382 | rdmsr(MSR_P4_MISC_ENABLE, misc_enable, dummy); | |
383 | if (!(misc_enable & MSR_P4_MISC_ENABLE_PERF_AVAIL)) | |
384 | return 0; | |
385 | ||
386 | nmi_perfctr_msr = MSR_P4_IQ_COUNTER0; | |
387 | nmi_p4_cccr_val = P4_NMI_IQ_CCCR0; | |
388 | #ifdef CONFIG_SMP | |
389 | if (smp_num_siblings == 2) | |
390 | nmi_p4_cccr_val |= P4_CCCR_OVF_PMI1; | |
391 | #endif | |
392 | ||
393 | if (!(misc_enable & MSR_P4_MISC_ENABLE_PEBS_UNAVAIL)) | |
394 | clear_msr_range(0x3F1, 2); | |
395 | /* MSR 0x3F0 seems to have a default value of 0xFC00, but current | |
396 | docs doesn't fully define it, so leave it alone for now. */ | |
397 | if (boot_cpu_data.x86_model >= 0x3) { | |
398 | /* MSR_P4_IQ_ESCR0/1 (0x3ba/0x3bb) removed */ | |
399 | clear_msr_range(0x3A0, 26); | |
400 | clear_msr_range(0x3BC, 3); | |
401 | } else { | |
402 | clear_msr_range(0x3A0, 31); | |
403 | } | |
404 | clear_msr_range(0x3C0, 6); | |
405 | clear_msr_range(0x3C8, 6); | |
406 | clear_msr_range(0x3E0, 2); | |
407 | clear_msr_range(MSR_P4_CCCR0, 18); | |
408 | clear_msr_range(MSR_P4_PERFCTR0, 18); | |
409 | ||
410 | wrmsr(MSR_P4_CRU_ESCR0, P4_NMI_CRU_ESCR0, 0); | |
411 | wrmsr(MSR_P4_IQ_CCCR0, P4_NMI_IQ_CCCR0 & ~P4_CCCR_ENABLE, 0); | |
7fbb4f6e | 412 | write_watchdog_counter("P4_IQ_COUNTER0"); |
1da177e4 LT |
413 | apic_write(APIC_LVTPC, APIC_DM_NMI); |
414 | wrmsr(MSR_P4_IQ_CCCR0, nmi_p4_cccr_val, 0); | |
415 | return 1; | |
416 | } | |
417 | ||
418 | void setup_apic_nmi_watchdog (void) | |
419 | { | |
420 | switch (boot_cpu_data.x86_vendor) { | |
421 | case X86_VENDOR_AMD: | |
422 | if (boot_cpu_data.x86 != 6 && boot_cpu_data.x86 != 15) | |
423 | return; | |
424 | setup_k7_watchdog(); | |
425 | break; | |
426 | case X86_VENDOR_INTEL: | |
427 | switch (boot_cpu_data.x86) { | |
428 | case 6: | |
429 | if (boot_cpu_data.x86_model > 0xd) | |
430 | return; | |
431 | ||
432 | setup_p6_watchdog(); | |
433 | break; | |
434 | case 15: | |
435 | if (boot_cpu_data.x86_model > 0x3) | |
436 | return; | |
437 | ||
438 | if (!setup_p4_watchdog()) | |
439 | return; | |
440 | break; | |
441 | default: | |
442 | return; | |
443 | } | |
444 | break; | |
445 | default: | |
446 | return; | |
447 | } | |
448 | lapic_nmi_owner = LAPIC_NMI_WATCHDOG; | |
449 | nmi_active = 1; | |
450 | } | |
451 | ||
452 | /* | |
453 | * the best way to detect whether a CPU has a 'hard lockup' problem | |
454 | * is to check it's local APIC timer IRQ counts. If they are not | |
455 | * changing then that CPU has some problem. | |
456 | * | |
457 | * as these watchdog NMI IRQs are generated on every CPU, we only | |
458 | * have to check the current processor. | |
459 | * | |
460 | * since NMIs don't listen to _any_ locks, we have to be extremely | |
461 | * careful not to rely on unsafe variables. The printk might lock | |
462 | * up though, so we have to break up any console locks first ... | |
463 | * [when there will be more tty-related locks, break them up | |
464 | * here too!] | |
465 | */ | |
466 | ||
467 | static unsigned int | |
468 | last_irq_sums [NR_CPUS], | |
469 | alert_counter [NR_CPUS]; | |
470 | ||
471 | void touch_nmi_watchdog (void) | |
472 | { | |
473 | int i; | |
474 | ||
475 | /* | |
476 | * Just reset the alert counters, (other CPUs might be | |
477 | * spinning on locks we hold): | |
478 | */ | |
479 | for (i = 0; i < NR_CPUS; i++) | |
480 | alert_counter[i] = 0; | |
481 | } | |
482 | ||
483 | extern void die_nmi(struct pt_regs *, const char *msg); | |
484 | ||
485 | void nmi_watchdog_tick (struct pt_regs * regs) | |
486 | { | |
487 | ||
488 | /* | |
489 | * Since current_thread_info()-> is always on the stack, and we | |
490 | * always switch the stack NMI-atomically, it's safe to use | |
491 | * smp_processor_id(). | |
492 | */ | |
493 | int sum, cpu = smp_processor_id(); | |
494 | ||
495 | sum = per_cpu(irq_stat, cpu).apic_timer_irqs; | |
496 | ||
497 | if (last_irq_sums[cpu] == sum) { | |
498 | /* | |
499 | * Ayiee, looks like this CPU is stuck ... | |
500 | * wait a few IRQs (5 seconds) before doing the oops ... | |
501 | */ | |
502 | alert_counter[cpu]++; | |
503 | if (alert_counter[cpu] == 5*nmi_hz) | |
504 | die_nmi(regs, "NMI Watchdog detected LOCKUP"); | |
505 | } else { | |
506 | last_irq_sums[cpu] = sum; | |
507 | alert_counter[cpu] = 0; | |
508 | } | |
509 | if (nmi_perfctr_msr) { | |
510 | if (nmi_perfctr_msr == MSR_P4_IQ_COUNTER0) { | |
511 | /* | |
512 | * P4 quirks: | |
513 | * - An overflown perfctr will assert its interrupt | |
514 | * until the OVF flag in its CCCR is cleared. | |
515 | * - LVTPC is masked on interrupt and must be | |
516 | * unmasked by the LVTPC handler. | |
517 | */ | |
518 | wrmsr(MSR_P4_IQ_CCCR0, nmi_p4_cccr_val, 0); | |
519 | apic_write(APIC_LVTPC, APIC_DM_NMI); | |
520 | } | |
521 | else if (nmi_perfctr_msr == MSR_P6_PERFCTR0) { | |
522 | /* Only P6 based Pentium M need to re-unmask | |
523 | * the apic vector but it doesn't hurt | |
524 | * other P6 variant */ | |
525 | apic_write(APIC_LVTPC, APIC_DM_NMI); | |
526 | } | |
7fbb4f6e | 527 | write_watchdog_counter(NULL); |
1da177e4 LT |
528 | } |
529 | } | |
530 | ||
531 | #ifdef CONFIG_SYSCTL | |
532 | ||
533 | static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu) | |
534 | { | |
535 | unsigned char reason = get_nmi_reason(); | |
536 | char buf[64]; | |
537 | ||
538 | if (!(reason & 0xc0)) { | |
539 | sprintf(buf, "NMI received for unknown reason %02x\n", reason); | |
540 | die_nmi(regs, buf); | |
541 | } | |
542 | return 0; | |
543 | } | |
544 | ||
545 | /* | |
546 | * proc handler for /proc/sys/kernel/unknown_nmi_panic | |
547 | */ | |
548 | int proc_unknown_nmi_panic(ctl_table *table, int write, struct file *file, | |
549 | void __user *buffer, size_t *length, loff_t *ppos) | |
550 | { | |
551 | int old_state; | |
552 | ||
553 | old_state = unknown_nmi_panic; | |
554 | proc_dointvec(table, write, file, buffer, length, ppos); | |
555 | if (!!old_state == !!unknown_nmi_panic) | |
556 | return 0; | |
557 | ||
558 | if (unknown_nmi_panic) { | |
559 | if (reserve_lapic_nmi() < 0) { | |
560 | unknown_nmi_panic = 0; | |
561 | return -EBUSY; | |
562 | } else { | |
563 | set_nmi_callback(unknown_nmi_panic_callback); | |
564 | } | |
565 | } else { | |
566 | release_lapic_nmi(); | |
567 | unset_nmi_callback(); | |
568 | } | |
569 | return 0; | |
570 | } | |
571 | ||
572 | #endif | |
573 | ||
574 | EXPORT_SYMBOL(nmi_active); | |
575 | EXPORT_SYMBOL(nmi_watchdog); | |
576 | EXPORT_SYMBOL(reserve_lapic_nmi); | |
577 | EXPORT_SYMBOL(release_lapic_nmi); | |
578 | EXPORT_SYMBOL(disable_timer_nmi_watchdog); | |
579 | EXPORT_SYMBOL(enable_timer_nmi_watchdog); |