timer_list.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * List pending timers
  4 *
  5 * Copyright(C) 2006, Red Hat, Inc., Ingo Molnar
  6 */
  7
  8#include <linux/proc_fs.h>
  9#include <linux/module.h>
 10#include <linux/spinlock.h>
 11#include <linux/sched.h>
 12#include <linux/seq_file.h>
 13#include <linux/kallsyms.h>
 14#include <linux/nmi.h>
 15
 16#include <linux/uaccess.h>
 17
 18#include "tick-internal.h"
 19
 20struct timer_list_iter {
 21	int cpu;
 22	bool second_pass;
 23	u64 now;
 24};
 25
 26/*
 27 * This allows printing both to /proc/timer_list and
 28 * to the console (on SysRq-Q):
 29 */
 30__printf(2, 3)
 31static void SEQ_printf(struct seq_file *m, const char *fmt, ...)
 32{
 33	va_list args;
 34
 35	va_start(args, fmt);
 36
 37	if (m)
 38		seq_vprintf(m, fmt, args);
 39	else
 40		vprintk(fmt, args);
 41
 42	va_end(args);
 43}
 44
 45static void
 46print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
 47	    int idx, u64 now)
 48{
 49	SEQ_printf(m, " #%d: <%p>, %ps", idx, taddr, ACCESS_PRIVATE(timer, function));
 50	SEQ_printf(m, ", S:%02x", timer->state);
 51	SEQ_printf(m, "\n");
 52	SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
 53		(unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
 54		(unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
 55		(long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
 56		(long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
 57}
 58
 59static void
 60print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
 61		    u64 now)
 62{
 63	struct hrtimer *timer, tmp;
 64	unsigned long next = 0, i;
 65	struct timerqueue_node *curr;
 66	unsigned long flags;
 67
 68next_one:
 69	i = 0;
 70
 71	touch_nmi_watchdog();
 72
 73	raw_spin_lock_irqsave(&base->cpu_base->lock, flags);
 74
 75	curr = timerqueue_getnext(&base->active);
 76	/*
 77	 * Crude but we have to do this O(N*N) thing, because
 78	 * we have to unlock the base when printing:
 79	 */
 80	while (curr && i < next) {
 81		curr = timerqueue_iterate_next(curr);
 82		i++;
 83	}
 84
 85	if (curr) {
 86
 87		timer = container_of(curr, struct hrtimer, node);
 88		tmp = *timer;
 89		raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 90
 91		print_timer(m, timer, &tmp, i, now);
 92		next++;
 93		goto next_one;
 94	}
 95	raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 96}
 97
 98static void
 99print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
100{
101	SEQ_printf(m, "  .base:       %p\n", base);
102	SEQ_printf(m, "  .index:      %d\n", base->index);
103
104	SEQ_printf(m, "  .resolution: %u nsecs\n", hrtimer_resolution);
105#ifdef CONFIG_HIGH_RES_TIMERS
106	SEQ_printf(m, "  .offset:     %Lu nsecs\n",
107		   (unsigned long long) ktime_to_ns(base->offset));
108#endif
109	SEQ_printf(m,   "active timers:\n");
110	print_active_timers(m, base, now + ktime_to_ns(base->offset));
111}
112
113static void print_cpu(struct seq_file *m, int cpu, u64 now)
114{
115	struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
116	int i;
117
118	SEQ_printf(m, "cpu: %d\n", cpu);
119	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
120		SEQ_printf(m, " clock %d:\n", i);
121		print_base(m, cpu_base->clock_base + i, now);
122	}
123#define P(x) \
124	SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
125		   (unsigned long long)(cpu_base->x))
126#define P_ns(x) \
127	SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
128		   (unsigned long long)(ktime_to_ns(cpu_base->x)))
129
130#ifdef CONFIG_HIGH_RES_TIMERS
131	P_ns(expires_next);
132	P(hres_active);
133	P(nr_events);
134	P(nr_retries);
135	P(nr_hangs);
136	P(max_hang_time);
137#endif
138#undef P
139#undef P_ns
140
141#ifdef CONFIG_TICK_ONESHOT
142# define P(x) \
143	SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
144		   (unsigned long long)(ts->x))
145# define P_ns(x) \
146	SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
147		   (unsigned long long)(ktime_to_ns(ts->x)))
148# define P_flag(x, f)			    \
149	SEQ_printf(m, "  .%-15s: %d\n", #x, !!(ts->flags & (f)))
150
151	{
152		struct tick_sched *ts = tick_get_tick_sched(cpu);
153		P_flag(nohz, TS_FLAG_NOHZ);
154		P_flag(highres, TS_FLAG_HIGHRES);
155		P_ns(last_tick);
156		P_flag(tick_stopped, TS_FLAG_STOPPED);
157		P(idle_jiffies);
158		P(idle_calls);
159		P(idle_sleeps);
160		P_ns(idle_entrytime);
161		P_ns(idle_waketime);
162		P_ns(idle_exittime);
163		P_ns(idle_sleeptime);
164		P_ns(iowait_sleeptime);
165		P(last_jiffies);
166		P(next_timer);
167		P_ns(idle_expires);
168		SEQ_printf(m, "jiffies: %Lu\n",
169			   (unsigned long long)jiffies);
170	}
171#endif
172
173#undef P
174#undef P_ns
175	SEQ_printf(m, "\n");
176}
177
178#ifdef CONFIG_GENERIC_CLOCKEVENTS
179static void
180print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
181{
182	struct clock_event_device *dev = td->evtdev;
183
184	touch_nmi_watchdog();
185
186	SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
187	if (cpu < 0)
188		SEQ_printf(m, "Broadcast device\n");
189	else
190		SEQ_printf(m, "Per CPU device: %d\n", cpu);
191
192	SEQ_printf(m, "Clock Event Device: ");
193	if (!dev) {
194		SEQ_printf(m, "<NULL>\n");
195		return;
196	}
197	SEQ_printf(m, "%s\n", dev->name);
198	SEQ_printf(m, " max_delta_ns:   %llu\n",
199		   (unsigned long long) dev->max_delta_ns);
200	SEQ_printf(m, " min_delta_ns:   %llu\n",
201		   (unsigned long long) dev->min_delta_ns);
202	SEQ_printf(m, " mult:           %u\n", dev->mult);
203	SEQ_printf(m, " shift:          %u\n", dev->shift);
204	SEQ_printf(m, " mode:           %d\n", clockevent_get_state(dev));
205	SEQ_printf(m, " next_event:     %Ld nsecs\n",
206		   (unsigned long long) ktime_to_ns(dev->next_event));
207
208	SEQ_printf(m, " set_next_event: %ps\n", dev->set_next_event);
209
210	if (dev->set_state_shutdown)
211		SEQ_printf(m, " shutdown:       %ps\n",
212			dev->set_state_shutdown);
213
214	if (dev->set_state_periodic)
215		SEQ_printf(m, " periodic:       %ps\n",
216			dev->set_state_periodic);
217
218	if (dev->set_state_oneshot)
219		SEQ_printf(m, " oneshot:        %ps\n",
220			dev->set_state_oneshot);
221
222	if (dev->set_state_oneshot_stopped)
223		SEQ_printf(m, " oneshot stopped: %ps\n",
224			dev->set_state_oneshot_stopped);
225
226	if (dev->tick_resume)
227		SEQ_printf(m, " resume:         %ps\n",
228			dev->tick_resume);
229
230	SEQ_printf(m, " event_handler:  %ps\n", dev->event_handler);
231	SEQ_printf(m, "\n");
232	SEQ_printf(m, " retries:        %lu\n", dev->retries);
233
234#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
235	if (cpu >= 0) {
236		const struct clock_event_device *wd = tick_get_wakeup_device(cpu);
237
238		SEQ_printf(m, "Wakeup Device: %s\n", wd ? wd->name : "<NULL>");
239	}
240#endif
241	SEQ_printf(m, "\n");
242}
243
244static void timer_list_show_tickdevices_header(struct seq_file *m)
245{
246#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
247	print_tickdevice(m, tick_get_broadcast_device(), -1);
248	SEQ_printf(m, "tick_broadcast_mask: %*pb\n",
249		   cpumask_pr_args(tick_get_broadcast_mask()));
250#ifdef CONFIG_TICK_ONESHOT
251	SEQ_printf(m, "tick_broadcast_oneshot_mask: %*pb\n",
252		   cpumask_pr_args(tick_get_broadcast_oneshot_mask()));
253#endif
254	SEQ_printf(m, "\n");
255#endif
256}
257#endif
258
259static inline void timer_list_header(struct seq_file *m, u64 now)
260{
261	SEQ_printf(m, "Timer List Version: v0.10\n");
262	SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
263	SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
264	SEQ_printf(m, "\n");
265}
266
267void sysrq_timer_list_show(void)
268{
269	u64 now = ktime_to_ns(ktime_get());
270	int cpu;
271
272	timer_list_header(NULL, now);
273
274	for_each_online_cpu(cpu)
275		print_cpu(NULL, cpu, now);
276
277#ifdef CONFIG_GENERIC_CLOCKEVENTS
278	timer_list_show_tickdevices_header(NULL);
279	for_each_online_cpu(cpu)
280		print_tickdevice(NULL, tick_get_device(cpu), cpu);
281#endif
282	return;
283}
284
285#ifdef CONFIG_PROC_FS
286static int timer_list_show(struct seq_file *m, void *v)
287{
288	struct timer_list_iter *iter = v;
289
290	if (iter->cpu == -1 && !iter->second_pass)
291		timer_list_header(m, iter->now);
292	else if (!iter->second_pass)
293		print_cpu(m, iter->cpu, iter->now);
294#ifdef CONFIG_GENERIC_CLOCKEVENTS
295	else if (iter->cpu == -1 && iter->second_pass)
296		timer_list_show_tickdevices_header(m);
297	else
298		print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
299#endif
300	return 0;
301}
302
303static void *move_iter(struct timer_list_iter *iter, loff_t offset)
304{
305	for (; offset; offset--) {
306		iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
307		if (iter->cpu >= nr_cpu_ids) {
308#ifdef CONFIG_GENERIC_CLOCKEVENTS
309			if (!iter->second_pass) {
310				iter->cpu = -1;
311				iter->second_pass = true;
312			} else
313				return NULL;
314#else
315			return NULL;
316#endif
317		}
318	}
319	return iter;
320}
321
322static void *timer_list_start(struct seq_file *file, loff_t *offset)
323{
324	struct timer_list_iter *iter = file->private;
325
326	if (!*offset)
327		iter->now = ktime_to_ns(ktime_get());
328	iter->cpu = -1;
329	iter->second_pass = false;
330	return move_iter(iter, *offset);
331}
332
333static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
334{
335	struct timer_list_iter *iter = file->private;
336	++*offset;
337	return move_iter(iter, 1);
338}
339
340static void timer_list_stop(struct seq_file *seq, void *v)
341{
342}
343
344static const struct seq_operations timer_list_sops = {
345	.start = timer_list_start,
346	.next = timer_list_next,
347	.stop = timer_list_stop,
348	.show = timer_list_show,
349};
350
351static int __init init_timer_list_procfs(void)
352{
353	struct proc_dir_entry *pe;
354
355	pe = proc_create_seq_private("timer_list", 0400, NULL, &timer_list_sops,
356			sizeof(struct timer_list_iter), NULL);
357	if (!pe)
358		return -ENOMEM;
359	return 0;
360}
361__initcall(init_timer_list_procfs);
362#endif