xref: /openbmc/linux/kernel/time/timer_list.c (revision 6aa7de05)
1 /*
2  * kernel/time/timer_list.c
3  *
4  * List pending timers
5  *
6  * Copyright(C) 2006, Red Hat, Inc., Ingo Molnar
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12 
13 #include <linux/proc_fs.h>
14 #include <linux/module.h>
15 #include <linux/spinlock.h>
16 #include <linux/sched.h>
17 #include <linux/seq_file.h>
18 #include <linux/kallsyms.h>
19 #include <linux/nmi.h>
20 
21 #include <linux/uaccess.h>
22 
23 #include "tick-internal.h"
24 
25 struct timer_list_iter {
26 	int cpu;
27 	bool second_pass;
28 	u64 now;
29 };
30 
31 typedef void (*print_fn_t)(struct seq_file *m, unsigned int *classes);
32 
33 /*
34  * This allows printing both to /proc/timer_list and
35  * to the console (on SysRq-Q):
36  */
37 __printf(2, 3)
38 static void SEQ_printf(struct seq_file *m, const char *fmt, ...)
39 {
40 	va_list args;
41 
42 	va_start(args, fmt);
43 
44 	if (m)
45 		seq_vprintf(m, fmt, args);
46 	else
47 		vprintk(fmt, args);
48 
49 	va_end(args);
50 }
51 
52 static void print_name_offset(struct seq_file *m, void *sym)
53 {
54 	char symname[KSYM_NAME_LEN];
55 
56 	if (lookup_symbol_name((unsigned long)sym, symname) < 0)
57 		SEQ_printf(m, "<%pK>", sym);
58 	else
59 		SEQ_printf(m, "%s", symname);
60 }
61 
62 static void
63 print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
64 	    int idx, u64 now)
65 {
66 	SEQ_printf(m, " #%d: ", idx);
67 	print_name_offset(m, taddr);
68 	SEQ_printf(m, ", ");
69 	print_name_offset(m, timer->function);
70 	SEQ_printf(m, ", S:%02x", timer->state);
71 	SEQ_printf(m, "\n");
72 	SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
73 		(unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
74 		(unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
75 		(long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
76 		(long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
77 }
78 
79 static void
80 print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
81 		    u64 now)
82 {
83 	struct hrtimer *timer, tmp;
84 	unsigned long next = 0, i;
85 	struct timerqueue_node *curr;
86 	unsigned long flags;
87 
88 next_one:
89 	i = 0;
90 
91 	touch_nmi_watchdog();
92 
93 	raw_spin_lock_irqsave(&base->cpu_base->lock, flags);
94 
95 	curr = timerqueue_getnext(&base->active);
96 	/*
97 	 * Crude but we have to do this O(N*N) thing, because
98 	 * we have to unlock the base when printing:
99 	 */
100 	while (curr && i < next) {
101 		curr = timerqueue_iterate_next(curr);
102 		i++;
103 	}
104 
105 	if (curr) {
106 
107 		timer = container_of(curr, struct hrtimer, node);
108 		tmp = *timer;
109 		raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
110 
111 		print_timer(m, timer, &tmp, i, now);
112 		next++;
113 		goto next_one;
114 	}
115 	raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
116 }
117 
118 static void
119 print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
120 {
121 	SEQ_printf(m, "  .base:       %pK\n", base);
122 	SEQ_printf(m, "  .index:      %d\n", base->index);
123 
124 	SEQ_printf(m, "  .resolution: %u nsecs\n", hrtimer_resolution);
125 
126 	SEQ_printf(m,   "  .get_time:   ");
127 	print_name_offset(m, base->get_time);
128 	SEQ_printf(m,   "\n");
129 #ifdef CONFIG_HIGH_RES_TIMERS
130 	SEQ_printf(m, "  .offset:     %Lu nsecs\n",
131 		   (unsigned long long) ktime_to_ns(base->offset));
132 #endif
133 	SEQ_printf(m,   "active timers:\n");
134 	print_active_timers(m, base, now + ktime_to_ns(base->offset));
135 }
136 
137 static void print_cpu(struct seq_file *m, int cpu, u64 now)
138 {
139 	struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
140 	int i;
141 
142 	SEQ_printf(m, "cpu: %d\n", cpu);
143 	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
144 		SEQ_printf(m, " clock %d:\n", i);
145 		print_base(m, cpu_base->clock_base + i, now);
146 	}
147 #define P(x) \
148 	SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
149 		   (unsigned long long)(cpu_base->x))
150 #define P_ns(x) \
151 	SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
152 		   (unsigned long long)(ktime_to_ns(cpu_base->x)))
153 
154 #ifdef CONFIG_HIGH_RES_TIMERS
155 	P_ns(expires_next);
156 	P(hres_active);
157 	P(nr_events);
158 	P(nr_retries);
159 	P(nr_hangs);
160 	P(max_hang_time);
161 #endif
162 #undef P
163 #undef P_ns
164 
165 #ifdef CONFIG_TICK_ONESHOT
166 # define P(x) \
167 	SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
168 		   (unsigned long long)(ts->x))
169 # define P_ns(x) \
170 	SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
171 		   (unsigned long long)(ktime_to_ns(ts->x)))
172 	{
173 		struct tick_sched *ts = tick_get_tick_sched(cpu);
174 		P(nohz_mode);
175 		P_ns(last_tick);
176 		P(tick_stopped);
177 		P(idle_jiffies);
178 		P(idle_calls);
179 		P(idle_sleeps);
180 		P_ns(idle_entrytime);
181 		P_ns(idle_waketime);
182 		P_ns(idle_exittime);
183 		P_ns(idle_sleeptime);
184 		P_ns(iowait_sleeptime);
185 		P(last_jiffies);
186 		P(next_timer);
187 		P_ns(idle_expires);
188 		SEQ_printf(m, "jiffies: %Lu\n",
189 			   (unsigned long long)jiffies);
190 	}
191 #endif
192 
193 #undef P
194 #undef P_ns
195 	SEQ_printf(m, "\n");
196 }
197 
198 #ifdef CONFIG_GENERIC_CLOCKEVENTS
199 static void
200 print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
201 {
202 	struct clock_event_device *dev = td->evtdev;
203 
204 	touch_nmi_watchdog();
205 
206 	SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
207 	if (cpu < 0)
208 		SEQ_printf(m, "Broadcast device\n");
209 	else
210 		SEQ_printf(m, "Per CPU device: %d\n", cpu);
211 
212 	SEQ_printf(m, "Clock Event Device: ");
213 	if (!dev) {
214 		SEQ_printf(m, "<NULL>\n");
215 		return;
216 	}
217 	SEQ_printf(m, "%s\n", dev->name);
218 	SEQ_printf(m, " max_delta_ns:   %llu\n",
219 		   (unsigned long long) dev->max_delta_ns);
220 	SEQ_printf(m, " min_delta_ns:   %llu\n",
221 		   (unsigned long long) dev->min_delta_ns);
222 	SEQ_printf(m, " mult:           %u\n", dev->mult);
223 	SEQ_printf(m, " shift:          %u\n", dev->shift);
224 	SEQ_printf(m, " mode:           %d\n", clockevent_get_state(dev));
225 	SEQ_printf(m, " next_event:     %Ld nsecs\n",
226 		   (unsigned long long) ktime_to_ns(dev->next_event));
227 
228 	SEQ_printf(m, " set_next_event: ");
229 	print_name_offset(m, dev->set_next_event);
230 	SEQ_printf(m, "\n");
231 
232 	if (dev->set_state_shutdown) {
233 		SEQ_printf(m, " shutdown: ");
234 		print_name_offset(m, dev->set_state_shutdown);
235 		SEQ_printf(m, "\n");
236 	}
237 
238 	if (dev->set_state_periodic) {
239 		SEQ_printf(m, " periodic: ");
240 		print_name_offset(m, dev->set_state_periodic);
241 		SEQ_printf(m, "\n");
242 	}
243 
244 	if (dev->set_state_oneshot) {
245 		SEQ_printf(m, " oneshot:  ");
246 		print_name_offset(m, dev->set_state_oneshot);
247 		SEQ_printf(m, "\n");
248 	}
249 
250 	if (dev->set_state_oneshot_stopped) {
251 		SEQ_printf(m, " oneshot stopped: ");
252 		print_name_offset(m, dev->set_state_oneshot_stopped);
253 		SEQ_printf(m, "\n");
254 	}
255 
256 	if (dev->tick_resume) {
257 		SEQ_printf(m, " resume:   ");
258 		print_name_offset(m, dev->tick_resume);
259 		SEQ_printf(m, "\n");
260 	}
261 
262 	SEQ_printf(m, " event_handler:  ");
263 	print_name_offset(m, dev->event_handler);
264 	SEQ_printf(m, "\n");
265 	SEQ_printf(m, " retries:        %lu\n", dev->retries);
266 	SEQ_printf(m, "\n");
267 }
268 
269 static void timer_list_show_tickdevices_header(struct seq_file *m)
270 {
271 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
272 	print_tickdevice(m, tick_get_broadcast_device(), -1);
273 	SEQ_printf(m, "tick_broadcast_mask: %*pb\n",
274 		   cpumask_pr_args(tick_get_broadcast_mask()));
275 #ifdef CONFIG_TICK_ONESHOT
276 	SEQ_printf(m, "tick_broadcast_oneshot_mask: %*pb\n",
277 		   cpumask_pr_args(tick_get_broadcast_oneshot_mask()));
278 #endif
279 	SEQ_printf(m, "\n");
280 #endif
281 }
282 #endif
283 
284 static inline void timer_list_header(struct seq_file *m, u64 now)
285 {
286 	SEQ_printf(m, "Timer List Version: v0.8\n");
287 	SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
288 	SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
289 	SEQ_printf(m, "\n");
290 }
291 
292 static int timer_list_show(struct seq_file *m, void *v)
293 {
294 	struct timer_list_iter *iter = v;
295 
296 	if (iter->cpu == -1 && !iter->second_pass)
297 		timer_list_header(m, iter->now);
298 	else if (!iter->second_pass)
299 		print_cpu(m, iter->cpu, iter->now);
300 #ifdef CONFIG_GENERIC_CLOCKEVENTS
301 	else if (iter->cpu == -1 && iter->second_pass)
302 		timer_list_show_tickdevices_header(m);
303 	else
304 		print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
305 #endif
306 	return 0;
307 }
308 
309 void sysrq_timer_list_show(void)
310 {
311 	u64 now = ktime_to_ns(ktime_get());
312 	int cpu;
313 
314 	timer_list_header(NULL, now);
315 
316 	for_each_online_cpu(cpu)
317 		print_cpu(NULL, cpu, now);
318 
319 #ifdef CONFIG_GENERIC_CLOCKEVENTS
320 	timer_list_show_tickdevices_header(NULL);
321 	for_each_online_cpu(cpu)
322 		print_tickdevice(NULL, tick_get_device(cpu), cpu);
323 #endif
324 	return;
325 }
326 
327 static void *move_iter(struct timer_list_iter *iter, loff_t offset)
328 {
329 	for (; offset; offset--) {
330 		iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
331 		if (iter->cpu >= nr_cpu_ids) {
332 #ifdef CONFIG_GENERIC_CLOCKEVENTS
333 			if (!iter->second_pass) {
334 				iter->cpu = -1;
335 				iter->second_pass = true;
336 			} else
337 				return NULL;
338 #else
339 			return NULL;
340 #endif
341 		}
342 	}
343 	return iter;
344 }
345 
346 static void *timer_list_start(struct seq_file *file, loff_t *offset)
347 {
348 	struct timer_list_iter *iter = file->private;
349 
350 	if (!*offset)
351 		iter->now = ktime_to_ns(ktime_get());
352 	iter->cpu = -1;
353 	iter->second_pass = false;
354 	return move_iter(iter, *offset);
355 }
356 
357 static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
358 {
359 	struct timer_list_iter *iter = file->private;
360 	++*offset;
361 	return move_iter(iter, 1);
362 }
363 
364 static void timer_list_stop(struct seq_file *seq, void *v)
365 {
366 }
367 
368 static const struct seq_operations timer_list_sops = {
369 	.start = timer_list_start,
370 	.next = timer_list_next,
371 	.stop = timer_list_stop,
372 	.show = timer_list_show,
373 };
374 
375 static int timer_list_open(struct inode *inode, struct file *filp)
376 {
377 	return seq_open_private(filp, &timer_list_sops,
378 			sizeof(struct timer_list_iter));
379 }
380 
381 static const struct file_operations timer_list_fops = {
382 	.open		= timer_list_open,
383 	.read		= seq_read,
384 	.llseek		= seq_lseek,
385 	.release	= seq_release_private,
386 };
387 
388 static int __init init_timer_list_procfs(void)
389 {
390 	struct proc_dir_entry *pe;
391 
392 	pe = proc_create("timer_list", 0444, NULL, &timer_list_fops);
393 	if (!pe)
394 		return -ENOMEM;
395 	return 0;
396 }
397 __initcall(init_timer_list_procfs);
398