x86: add clflush before monitor for Intel 7400 series
[linux-2.6/mini2440.git] / arch / x86 / kernel / nmi.c
blob7228979f1e7f11015e2443cd7038a1b3f07f7cad
1 /*
2 * NMI watchdog support on APIC systems
4 * Started by Ingo Molnar <mingo@redhat.com>
6 * Fixes:
7 * Mikael Pettersson : AMD K7 support for local APIC NMI watchdog.
8 * Mikael Pettersson : Power Management for local APIC NMI watchdog.
9 * Mikael Pettersson : Pentium 4 support for local APIC NMI watchdog.
10 * Pavel Machek and
11 * Mikael Pettersson : PM converted to driver model. Disable/enable API.
14 #include <asm/apic.h>
16 #include <linux/nmi.h>
17 #include <linux/mm.h>
18 #include <linux/delay.h>
19 #include <linux/interrupt.h>
20 #include <linux/module.h>
21 #include <linux/sysdev.h>
22 #include <linux/sysctl.h>
23 #include <linux/percpu.h>
24 #include <linux/kprobes.h>
25 #include <linux/cpumask.h>
26 #include <linux/kernel_stat.h>
27 #include <linux/kdebug.h>
28 #include <linux/smp.h>
30 #include <asm/i8259.h>
31 #include <asm/io_apic.h>
32 #include <asm/proto.h>
33 #include <asm/timer.h>
35 #include <asm/mce.h>
37 #include <mach_traps.h>
39 int unknown_nmi_panic;
40 int nmi_watchdog_enabled;
42 static cpumask_t backtrace_mask = CPU_MASK_NONE;
44 /* nmi_active:
45 * >0: the lapic NMI watchdog is active, but can be disabled
46 * <0: the lapic NMI watchdog has not been set up, and cannot
47 * be enabled
48 * 0: the lapic NMI watchdog is disabled, but can be enabled
50 atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
51 EXPORT_SYMBOL(nmi_active);
53 unsigned int nmi_watchdog = NMI_NONE;
54 EXPORT_SYMBOL(nmi_watchdog);
56 static int panic_on_timeout;
58 static unsigned int nmi_hz = HZ;
59 static DEFINE_PER_CPU(short, wd_enabled);
60 static int endflag __initdata;
62 static inline unsigned int get_nmi_count(int cpu)
64 #ifdef CONFIG_X86_64
65 return cpu_pda(cpu)->__nmi_count;
66 #else
67 return nmi_count(cpu);
68 #endif
71 static inline int mce_in_progress(void)
73 #if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE)
74 return atomic_read(&mce_entry) > 0;
75 #endif
76 return 0;
80 * Take the local apic timer and PIT/HPET into account. We don't
81 * know which one is active, when we have highres/dyntick on
83 static inline unsigned int get_timer_irqs(int cpu)
85 #ifdef CONFIG_X86_64
86 return read_pda(apic_timer_irqs) + read_pda(irq0_irqs);
87 #else
88 return per_cpu(irq_stat, cpu).apic_timer_irqs +
89 per_cpu(irq_stat, cpu).irq0_irqs;
90 #endif
93 #ifdef CONFIG_SMP
95 * The performance counters used by NMI_LOCAL_APIC don't trigger when
96 * the CPU is idle. To make sure the NMI watchdog really ticks on all
97 * CPUs during the test make them busy.
99 static __init void nmi_cpu_busy(void *data)
101 local_irq_enable_in_hardirq();
103 * Intentionally don't use cpu_relax here. This is
104 * to make sure that the performance counter really ticks,
105 * even if there is a simulator or similar that catches the
106 * pause instruction. On a real HT machine this is fine because
107 * all other CPUs are busy with "useless" delay loops and don't
108 * care if they get somewhat less cycles.
110 while (endflag == 0)
111 mb();
113 #endif
115 static void report_broken_nmi(int cpu, int *prev_nmi_count)
117 printk(KERN_CONT "\n");
119 printk(KERN_WARNING
120 "WARNING: CPU#%d: NMI appears to be stuck (%d->%d)!\n",
121 cpu, prev_nmi_count[cpu], get_nmi_count(cpu));
123 printk(KERN_WARNING
124 "Please report this to bugzilla.kernel.org,\n");
125 printk(KERN_WARNING
126 "and attach the output of the 'dmesg' command.\n");
128 per_cpu(wd_enabled, cpu) = 0;
129 atomic_dec(&nmi_active);
132 static void __acpi_nmi_disable(void *__unused)
134 apic_write(APIC_LVT0, APIC_DM_NMI | APIC_LVT_MASKED);
137 int __init check_nmi_watchdog(void)
139 unsigned int *prev_nmi_count;
140 int cpu;
142 if (!nmi_watchdog_active() || !atomic_read(&nmi_active))
143 return 0;
145 prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
146 if (!prev_nmi_count)
147 goto error;
149 printk(KERN_INFO "Testing NMI watchdog ... ");
151 #ifdef CONFIG_SMP
152 if (nmi_watchdog == NMI_LOCAL_APIC)
153 smp_call_function(nmi_cpu_busy, (void *)&endflag, 0);
154 #endif
156 for_each_possible_cpu(cpu)
157 prev_nmi_count[cpu] = get_nmi_count(cpu);
158 local_irq_enable();
159 mdelay((20 * 1000) / nmi_hz); /* wait 20 ticks */
161 for_each_online_cpu(cpu) {
162 if (!per_cpu(wd_enabled, cpu))
163 continue;
164 if (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5)
165 report_broken_nmi(cpu, prev_nmi_count);
167 endflag = 1;
168 if (!atomic_read(&nmi_active)) {
169 kfree(prev_nmi_count);
170 atomic_set(&nmi_active, -1);
171 goto error;
173 printk("OK.\n");
176 * now that we know it works we can reduce NMI frequency to
177 * something more reasonable; makes a difference in some configs
179 if (nmi_watchdog == NMI_LOCAL_APIC)
180 nmi_hz = lapic_adjust_nmi_hz(1);
182 kfree(prev_nmi_count);
183 return 0;
184 error:
185 if (nmi_watchdog == NMI_IO_APIC) {
186 if (!timer_through_8259)
187 disable_8259A_irq(0);
188 on_each_cpu(__acpi_nmi_disable, NULL, 1);
191 #ifdef CONFIG_X86_32
192 timer_ack = 0;
193 #endif
194 return -1;
197 static int __init setup_nmi_watchdog(char *str)
199 unsigned int nmi;
201 if (!strncmp(str, "panic", 5)) {
202 panic_on_timeout = 1;
203 str = strchr(str, ',');
204 if (!str)
205 return 1;
206 ++str;
209 if (!strncmp(str, "lapic", 5))
210 nmi_watchdog = NMI_LOCAL_APIC;
211 else if (!strncmp(str, "ioapic", 6))
212 nmi_watchdog = NMI_IO_APIC;
213 else {
214 get_option(&str, &nmi);
215 if (nmi >= NMI_INVALID)
216 return 0;
217 nmi_watchdog = nmi;
220 return 1;
222 __setup("nmi_watchdog=", setup_nmi_watchdog);
225 * Suspend/resume support
227 #ifdef CONFIG_PM
229 static int nmi_pm_active; /* nmi_active before suspend */
231 static int lapic_nmi_suspend(struct sys_device *dev, pm_message_t state)
233 /* only CPU0 goes here, other CPUs should be offline */
234 nmi_pm_active = atomic_read(&nmi_active);
235 stop_apic_nmi_watchdog(NULL);
236 BUG_ON(atomic_read(&nmi_active) != 0);
237 return 0;
240 static int lapic_nmi_resume(struct sys_device *dev)
242 /* only CPU0 goes here, other CPUs should be offline */
243 if (nmi_pm_active > 0) {
244 setup_apic_nmi_watchdog(NULL);
245 touch_nmi_watchdog();
247 return 0;
250 static struct sysdev_class nmi_sysclass = {
251 .name = "lapic_nmi",
252 .resume = lapic_nmi_resume,
253 .suspend = lapic_nmi_suspend,
256 static struct sys_device device_lapic_nmi = {
257 .id = 0,
258 .cls = &nmi_sysclass,
261 static int __init init_lapic_nmi_sysfs(void)
263 int error;
266 * should really be a BUG_ON but b/c this is an
267 * init call, it just doesn't work. -dcz
269 if (nmi_watchdog != NMI_LOCAL_APIC)
270 return 0;
272 if (atomic_read(&nmi_active) < 0)
273 return 0;
275 error = sysdev_class_register(&nmi_sysclass);
276 if (!error)
277 error = sysdev_register(&device_lapic_nmi);
278 return error;
281 /* must come after the local APIC's device_initcall() */
282 late_initcall(init_lapic_nmi_sysfs);
284 #endif /* CONFIG_PM */
286 static void __acpi_nmi_enable(void *__unused)
288 apic_write(APIC_LVT0, APIC_DM_NMI);
292 * Enable timer based NMIs on all CPUs:
294 void acpi_nmi_enable(void)
296 if (atomic_read(&nmi_active) && nmi_watchdog == NMI_IO_APIC)
297 on_each_cpu(__acpi_nmi_enable, NULL, 1);
301 * Disable timer based NMIs on all CPUs:
303 void acpi_nmi_disable(void)
305 if (atomic_read(&nmi_active) && nmi_watchdog == NMI_IO_APIC)
306 on_each_cpu(__acpi_nmi_disable, NULL, 1);
310 * This function is called as soon the LAPIC NMI watchdog driver has everything
311 * in place and it's ready to check if the NMIs belong to the NMI watchdog
313 void cpu_nmi_set_wd_enabled(void)
315 __get_cpu_var(wd_enabled) = 1;
318 void setup_apic_nmi_watchdog(void *unused)
320 if (__get_cpu_var(wd_enabled))
321 return;
323 /* cheap hack to support suspend/resume */
324 /* if cpu0 is not active neither should the other cpus */
325 if (smp_processor_id() != 0 && atomic_read(&nmi_active) <= 0)
326 return;
328 switch (nmi_watchdog) {
329 case NMI_LOCAL_APIC:
330 if (lapic_watchdog_init(nmi_hz) < 0) {
331 __get_cpu_var(wd_enabled) = 0;
332 return;
334 /* FALL THROUGH */
335 case NMI_IO_APIC:
336 __get_cpu_var(wd_enabled) = 1;
337 atomic_inc(&nmi_active);
341 void stop_apic_nmi_watchdog(void *unused)
343 /* only support LOCAL and IO APICs for now */
344 if (!nmi_watchdog_active())
345 return;
346 if (__get_cpu_var(wd_enabled) == 0)
347 return;
348 if (nmi_watchdog == NMI_LOCAL_APIC)
349 lapic_watchdog_stop();
350 else
351 __acpi_nmi_disable(NULL);
352 __get_cpu_var(wd_enabled) = 0;
353 atomic_dec(&nmi_active);
357 * the best way to detect whether a CPU has a 'hard lockup' problem
358 * is to check it's local APIC timer IRQ counts. If they are not
359 * changing then that CPU has some problem.
361 * as these watchdog NMI IRQs are generated on every CPU, we only
362 * have to check the current processor.
364 * since NMIs don't listen to _any_ locks, we have to be extremely
365 * careful not to rely on unsafe variables. The printk might lock
366 * up though, so we have to break up any console locks first ...
367 * [when there will be more tty-related locks, break them up here too!]
370 static DEFINE_PER_CPU(unsigned, last_irq_sum);
371 static DEFINE_PER_CPU(local_t, alert_counter);
372 static DEFINE_PER_CPU(int, nmi_touch);
374 void touch_nmi_watchdog(void)
376 if (nmi_watchdog_active()) {
377 unsigned cpu;
380 * Tell other CPUs to reset their alert counters. We cannot
381 * do it ourselves because the alert count increase is not
382 * atomic.
384 for_each_present_cpu(cpu) {
385 if (per_cpu(nmi_touch, cpu) != 1)
386 per_cpu(nmi_touch, cpu) = 1;
391 * Tickle the softlockup detector too:
393 touch_softlockup_watchdog();
395 EXPORT_SYMBOL(touch_nmi_watchdog);
397 notrace __kprobes int
398 nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
401 * Since current_thread_info()-> is always on the stack, and we
402 * always switch the stack NMI-atomically, it's safe to use
403 * smp_processor_id().
405 unsigned int sum;
406 int touched = 0;
407 int cpu = smp_processor_id();
408 int rc = 0;
410 /* check for other users first */
411 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
412 == NOTIFY_STOP) {
413 rc = 1;
414 touched = 1;
417 sum = get_timer_irqs(cpu);
419 if (__get_cpu_var(nmi_touch)) {
420 __get_cpu_var(nmi_touch) = 0;
421 touched = 1;
424 if (cpu_isset(cpu, backtrace_mask)) {
425 static DEFINE_SPINLOCK(lock); /* Serialise the printks */
427 spin_lock(&lock);
428 printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
429 dump_stack();
430 spin_unlock(&lock);
431 cpu_clear(cpu, backtrace_mask);
434 /* Could check oops_in_progress here too, but it's safer not to */
435 if (mce_in_progress())
436 touched = 1;
438 /* if the none of the timers isn't firing, this cpu isn't doing much */
439 if (!touched && __get_cpu_var(last_irq_sum) == sum) {
441 * Ayiee, looks like this CPU is stuck ...
442 * wait a few IRQs (5 seconds) before doing the oops ...
444 local_inc(&__get_cpu_var(alert_counter));
445 if (local_read(&__get_cpu_var(alert_counter)) == 5 * nmi_hz)
447 * die_nmi will return ONLY if NOTIFY_STOP happens..
449 die_nmi("BUG: NMI Watchdog detected LOCKUP",
450 regs, panic_on_timeout);
451 } else {
452 __get_cpu_var(last_irq_sum) = sum;
453 local_set(&__get_cpu_var(alert_counter), 0);
456 /* see if the nmi watchdog went off */
457 if (!__get_cpu_var(wd_enabled))
458 return rc;
459 switch (nmi_watchdog) {
460 case NMI_LOCAL_APIC:
461 rc |= lapic_wd_event(nmi_hz);
462 break;
463 case NMI_IO_APIC:
465 * don't know how to accurately check for this.
466 * just assume it was a watchdog timer interrupt
467 * This matches the old behaviour.
469 rc = 1;
470 break;
472 return rc;
475 #ifdef CONFIG_SYSCTL
477 static void enable_ioapic_nmi_watchdog_single(void *unused)
479 __get_cpu_var(wd_enabled) = 1;
480 atomic_inc(&nmi_active);
481 __acpi_nmi_enable(NULL);
484 static void enable_ioapic_nmi_watchdog(void)
486 on_each_cpu(enable_ioapic_nmi_watchdog_single, NULL, 1);
487 touch_nmi_watchdog();
490 static void disable_ioapic_nmi_watchdog(void)
492 on_each_cpu(stop_apic_nmi_watchdog, NULL, 1);
495 static int __init setup_unknown_nmi_panic(char *str)
497 unknown_nmi_panic = 1;
498 return 1;
500 __setup("unknown_nmi_panic", setup_unknown_nmi_panic);
502 static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
504 unsigned char reason = get_nmi_reason();
505 char buf[64];
507 sprintf(buf, "NMI received for unknown reason %02x\n", reason);
508 die_nmi(buf, regs, 1); /* Always panic here */
509 return 0;
513 * proc handler for /proc/sys/kernel/nmi
515 int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,
516 void __user *buffer, size_t *length, loff_t *ppos)
518 int old_state;
520 nmi_watchdog_enabled = (atomic_read(&nmi_active) > 0) ? 1 : 0;
521 old_state = nmi_watchdog_enabled;
522 proc_dointvec(table, write, file, buffer, length, ppos);
523 if (!!old_state == !!nmi_watchdog_enabled)
524 return 0;
526 if (atomic_read(&nmi_active) < 0 || !nmi_watchdog_active()) {
527 printk(KERN_WARNING
528 "NMI watchdog is permanently disabled\n");
529 return -EIO;
532 if (nmi_watchdog == NMI_LOCAL_APIC) {
533 if (nmi_watchdog_enabled)
534 enable_lapic_nmi_watchdog();
535 else
536 disable_lapic_nmi_watchdog();
537 } else if (nmi_watchdog == NMI_IO_APIC) {
538 if (nmi_watchdog_enabled)
539 enable_ioapic_nmi_watchdog();
540 else
541 disable_ioapic_nmi_watchdog();
542 } else {
543 printk(KERN_WARNING
544 "NMI watchdog doesn't know what hardware to touch\n");
545 return -EIO;
547 return 0;
550 #endif /* CONFIG_SYSCTL */
552 int do_nmi_callback(struct pt_regs *regs, int cpu)
554 #ifdef CONFIG_SYSCTL
555 if (unknown_nmi_panic)
556 return unknown_nmi_panic_callback(regs, cpu);
557 #endif
558 return 0;
561 void __trigger_all_cpu_backtrace(void)
563 int i;
565 backtrace_mask = cpu_online_map;
566 /* Wait for up to 10 seconds for all CPUs to do the backtrace */
567 for (i = 0; i < 10 * 1000; i++) {
568 if (cpus_empty(backtrace_mask))
569 break;
570 mdelay(1);