xref: /linux-6.15/kernel/time/timer_list.c (revision 930cc144)
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/tick.h>
20 
21 #include <asm/uaccess.h>
22 
23 typedef void (*print_fn_t)(struct seq_file *m, unsigned int *classes);
24 
25 DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
26 
27 /*
28  * This allows printing both to /proc/timer_list and
29  * to the console (on SysRq-Q):
30  */
31 #define SEQ_printf(m, x...)			\
32  do {						\
33 	if (m)					\
34 		seq_printf(m, x);		\
35 	else					\
36 		printk(x);			\
37  } while (0)
38 
39 static void print_name_offset(struct seq_file *m, void *sym)
40 {
41 	char symname[KSYM_NAME_LEN];
42 
43 	if (lookup_symbol_name((unsigned long)sym, symname) < 0)
44 		SEQ_printf(m, "<%p>", sym);
45 	else
46 		SEQ_printf(m, "%s", symname);
47 }
48 
49 static void
50 print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
51 	    int idx, u64 now)
52 {
53 #ifdef CONFIG_TIMER_STATS
54 	char tmp[TASK_COMM_LEN + 1];
55 #endif
56 	SEQ_printf(m, " #%d: ", idx);
57 	print_name_offset(m, taddr);
58 	SEQ_printf(m, ", ");
59 	print_name_offset(m, timer->function);
60 	SEQ_printf(m, ", S:%02lx", timer->state);
61 #ifdef CONFIG_TIMER_STATS
62 	SEQ_printf(m, ", ");
63 	print_name_offset(m, timer->start_site);
64 	memcpy(tmp, timer->start_comm, TASK_COMM_LEN);
65 	tmp[TASK_COMM_LEN] = 0;
66 	SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
67 #endif
68 	SEQ_printf(m, "\n");
69 	SEQ_printf(m, " # expires at %Lu nsecs [in %Ld nsecs]\n",
70 		(unsigned long long)ktime_to_ns(timer->expires),
71 		(long long)(ktime_to_ns(timer->expires) - now));
72 }
73 
74 static void
75 print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
76 		    u64 now)
77 {
78 	struct hrtimer *timer, tmp;
79 	unsigned long next = 0, i;
80 	struct rb_node *curr;
81 	unsigned long flags;
82 
83 next_one:
84 	i = 0;
85 	spin_lock_irqsave(&base->cpu_base->lock, flags);
86 
87 	curr = base->first;
88 	/*
89 	 * Crude but we have to do this O(N*N) thing, because
90 	 * we have to unlock the base when printing:
91 	 */
92 	while (curr && i < next) {
93 		curr = rb_next(curr);
94 		i++;
95 	}
96 
97 	if (curr) {
98 
99 		timer = rb_entry(curr, struct hrtimer, node);
100 		tmp = *timer;
101 		spin_unlock_irqrestore(&base->cpu_base->lock, flags);
102 
103 		print_timer(m, timer, &tmp, i, now);
104 		next++;
105 		goto next_one;
106 	}
107 	spin_unlock_irqrestore(&base->cpu_base->lock, flags);
108 }
109 
110 static void
111 print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
112 {
113 	SEQ_printf(m, "  .base:       %p\n", base);
114 	SEQ_printf(m, "  .index:      %d\n",
115 			base->index);
116 	SEQ_printf(m, "  .resolution: %Lu nsecs\n",
117 			(unsigned long long)ktime_to_ns(base->resolution));
118 	SEQ_printf(m,   "  .get_time:   ");
119 	print_name_offset(m, base->get_time);
120 	SEQ_printf(m,   "\n");
121 #ifdef CONFIG_HIGH_RES_TIMERS
122 	SEQ_printf(m, "  .offset:     %Lu nsecs\n",
123 		   (unsigned long long) ktime_to_ns(base->offset));
124 #endif
125 	SEQ_printf(m,   "active timers:\n");
126 	print_active_timers(m, base, now);
127 }
128 
129 static void print_cpu(struct seq_file *m, int cpu, u64 now)
130 {
131 	struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
132 	int i;
133 
134 	SEQ_printf(m, "\n");
135 	SEQ_printf(m, "cpu: %d\n", cpu);
136 	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
137 		SEQ_printf(m, " clock %d:\n", i);
138 		print_base(m, cpu_base->clock_base + i, now);
139 	}
140 #define P(x) \
141 	SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
142 		   (unsigned long long)(cpu_base->x))
143 #define P_ns(x) \
144 	SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
145 		   (unsigned long long)(ktime_to_ns(cpu_base->x)))
146 
147 #ifdef CONFIG_HIGH_RES_TIMERS
148 	P_ns(expires_next);
149 	P(hres_active);
150 	P(nr_events);
151 #endif
152 #undef P
153 #undef P_ns
154 
155 #ifdef CONFIG_TICK_ONESHOT
156 # define P(x) \
157 	SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
158 		   (unsigned long long)(ts->x))
159 # define P_ns(x) \
160 	SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
161 		   (unsigned long long)(ktime_to_ns(ts->x)))
162 	{
163 		struct tick_sched *ts = tick_get_tick_sched(cpu);
164 		P(nohz_mode);
165 		P_ns(idle_tick);
166 		P(tick_stopped);
167 		P(idle_jiffies);
168 		P(idle_calls);
169 		P(idle_sleeps);
170 		P_ns(idle_entrytime);
171 		P_ns(idle_waketime);
172 		P_ns(idle_exittime);
173 		P_ns(idle_sleeptime);
174 		P(last_jiffies);
175 		P(next_jiffies);
176 		P_ns(idle_expires);
177 		SEQ_printf(m, "jiffies: %Lu\n",
178 			   (unsigned long long)jiffies);
179 	}
180 #endif
181 
182 #undef P
183 #undef P_ns
184 }
185 
186 #ifdef CONFIG_GENERIC_CLOCKEVENTS
187 static void
188 print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
189 {
190 	struct clock_event_device *dev = td->evtdev;
191 
192 	SEQ_printf(m, "\n");
193 	SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
194 	if (cpu < 0)
195 		SEQ_printf(m, "Broadcast device\n");
196 	else
197 		SEQ_printf(m, "Per CPU device: %d\n", cpu);
198 
199 	SEQ_printf(m, "Clock Event Device: ");
200 	if (!dev) {
201 		SEQ_printf(m, "<NULL>\n");
202 		return;
203 	}
204 	SEQ_printf(m, "%s\n", dev->name);
205 	SEQ_printf(m, " max_delta_ns:   %lu\n", dev->max_delta_ns);
206 	SEQ_printf(m, " min_delta_ns:   %lu\n", dev->min_delta_ns);
207 	SEQ_printf(m, " mult:           %lu\n", dev->mult);
208 	SEQ_printf(m, " shift:          %d\n", dev->shift);
209 	SEQ_printf(m, " mode:           %d\n", dev->mode);
210 	SEQ_printf(m, " next_event:     %Ld nsecs\n",
211 		   (unsigned long long) ktime_to_ns(dev->next_event));
212 
213 	SEQ_printf(m, " set_next_event: ");
214 	print_name_offset(m, dev->set_next_event);
215 	SEQ_printf(m, "\n");
216 
217 	SEQ_printf(m, " set_mode:       ");
218 	print_name_offset(m, dev->set_mode);
219 	SEQ_printf(m, "\n");
220 
221 	SEQ_printf(m, " event_handler:  ");
222 	print_name_offset(m, dev->event_handler);
223 	SEQ_printf(m, "\n");
224 }
225 
226 static void timer_list_show_tickdevices(struct seq_file *m)
227 {
228 	int cpu;
229 
230 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
231 	print_tickdevice(m, tick_get_broadcast_device(), -1);
232 	SEQ_printf(m, "tick_broadcast_mask: %08lx\n",
233 		   tick_get_broadcast_mask()->bits[0]);
234 #ifdef CONFIG_TICK_ONESHOT
235 	SEQ_printf(m, "tick_broadcast_oneshot_mask: %08lx\n",
236 		   tick_get_broadcast_oneshot_mask()->bits[0]);
237 #endif
238 	SEQ_printf(m, "\n");
239 #endif
240 	for_each_online_cpu(cpu)
241 		print_tickdevice(m, tick_get_device(cpu), cpu);
242 	SEQ_printf(m, "\n");
243 }
244 #else
245 static void timer_list_show_tickdevices(struct seq_file *m) { }
246 #endif
247 
248 static int timer_list_show(struct seq_file *m, void *v)
249 {
250 	u64 now = ktime_to_ns(ktime_get());
251 	int cpu;
252 
253 	SEQ_printf(m, "Timer List Version: v0.4\n");
254 	SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
255 	SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
256 
257 	for_each_online_cpu(cpu)
258 		print_cpu(m, cpu, now);
259 
260 	SEQ_printf(m, "\n");
261 	timer_list_show_tickdevices(m);
262 
263 	return 0;
264 }
265 
266 void sysrq_timer_list_show(void)
267 {
268 	timer_list_show(NULL, NULL);
269 }
270 
271 static int timer_list_open(struct inode *inode, struct file *filp)
272 {
273 	return single_open(filp, timer_list_show, NULL);
274 }
275 
276 static struct file_operations timer_list_fops = {
277 	.open		= timer_list_open,
278 	.read		= seq_read,
279 	.llseek		= seq_lseek,
280 	.release	= single_release,
281 };
282 
283 static int __init init_timer_list_procfs(void)
284 {
285 	struct proc_dir_entry *pe;
286 
287 	pe = proc_create("timer_list", 0644, NULL, &timer_list_fops);
288 	if (!pe)
289 		return -ENOMEM;
290 	return 0;
291 }
292 __initcall(init_timer_list_procfs);
293