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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * trace context switch
4 *
5 * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
6 *
7 */
8#include <linux/module.h>
9#include <linux/kallsyms.h>
10#include <linux/uaccess.h>
11#include <linux/ftrace.h>
12#include <trace/events/sched.h>
13
14#include "trace.h"
15
16#define RECORD_CMDLINE 1
17#define RECORD_TGID 2
18
19static int sched_cmdline_ref;
20static int sched_tgid_ref;
21static DEFINE_MUTEX(sched_register_mutex);
22
23static void
24probe_sched_switch(void *ignore, bool preempt,
25 struct task_struct *prev, struct task_struct *next,
26 unsigned int prev_state)
27{
28 int flags;
29
30 flags = (RECORD_TGID * !!sched_tgid_ref) +
31 (RECORD_CMDLINE * !!sched_cmdline_ref);
32
33 if (!flags)
34 return;
35 tracing_record_taskinfo_sched_switch(prev, next, flags);
36}
37
38static void
39probe_sched_wakeup(void *ignore, struct task_struct *wakee)
40{
41 int flags;
42
43 flags = (RECORD_TGID * !!sched_tgid_ref) +
44 (RECORD_CMDLINE * !!sched_cmdline_ref);
45
46 if (!flags)
47 return;
48 tracing_record_taskinfo_sched_switch(current, wakee, flags);
49}
50
51static int tracing_sched_register(void)
52{
53 int ret;
54
55 ret = register_trace_sched_wakeup(probe_sched_wakeup, NULL);
56 if (ret) {
57 pr_info("wakeup trace: Couldn't activate tracepoint"
58 " probe to kernel_sched_wakeup\n");
59 return ret;
60 }
61
62 ret = register_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
63 if (ret) {
64 pr_info("wakeup trace: Couldn't activate tracepoint"
65 " probe to kernel_sched_wakeup_new\n");
66 goto fail_deprobe;
67 }
68
69 ret = register_trace_sched_switch(probe_sched_switch, NULL);
70 if (ret) {
71 pr_info("sched trace: Couldn't activate tracepoint"
72 " probe to kernel_sched_switch\n");
73 goto fail_deprobe_wake_new;
74 }
75
76 return ret;
77fail_deprobe_wake_new:
78 unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
79fail_deprobe:
80 unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
81 return ret;
82}
83
84static void tracing_sched_unregister(void)
85{
86 unregister_trace_sched_switch(probe_sched_switch, NULL);
87 unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
88 unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
89}
90
91static void tracing_start_sched_switch(int ops)
92{
93 bool sched_register;
94
95 mutex_lock(&sched_register_mutex);
96 sched_register = (!sched_cmdline_ref && !sched_tgid_ref);
97
98 switch (ops) {
99 case RECORD_CMDLINE:
100 sched_cmdline_ref++;
101 break;
102
103 case RECORD_TGID:
104 sched_tgid_ref++;
105 break;
106 }
107
108 if (sched_register && (sched_cmdline_ref || sched_tgid_ref))
109 tracing_sched_register();
110 mutex_unlock(&sched_register_mutex);
111}
112
113static void tracing_stop_sched_switch(int ops)
114{
115 mutex_lock(&sched_register_mutex);
116
117 switch (ops) {
118 case RECORD_CMDLINE:
119 sched_cmdline_ref--;
120 break;
121
122 case RECORD_TGID:
123 sched_tgid_ref--;
124 break;
125 }
126
127 if (!sched_cmdline_ref && !sched_tgid_ref)
128 tracing_sched_unregister();
129 mutex_unlock(&sched_register_mutex);
130}
131
132void tracing_start_cmdline_record(void)
133{
134 tracing_start_sched_switch(RECORD_CMDLINE);
135}
136
137void tracing_stop_cmdline_record(void)
138{
139 tracing_stop_sched_switch(RECORD_CMDLINE);
140}
141
142void tracing_start_tgid_record(void)
143{
144 tracing_start_sched_switch(RECORD_TGID);
145}
146
147void tracing_stop_tgid_record(void)
148{
149 tracing_stop_sched_switch(RECORD_TGID);
150}
1/*
2 * trace context switch
3 *
4 * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
5 *
6 */
7#include <linux/module.h>
8#include <linux/fs.h>
9#include <linux/debugfs.h>
10#include <linux/kallsyms.h>
11#include <linux/uaccess.h>
12#include <linux/ftrace.h>
13#include <trace/events/sched.h>
14
15#include "trace.h"
16
17static struct trace_array *ctx_trace;
18static int __read_mostly tracer_enabled;
19static int sched_ref;
20static DEFINE_MUTEX(sched_register_mutex);
21static int sched_stopped;
22
23
24void
25tracing_sched_switch_trace(struct trace_array *tr,
26 struct task_struct *prev,
27 struct task_struct *next,
28 unsigned long flags, int pc)
29{
30 struct ftrace_event_call *call = &event_context_switch;
31 struct ring_buffer *buffer = tr->trace_buffer.buffer;
32 struct ring_buffer_event *event;
33 struct ctx_switch_entry *entry;
34
35 event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
36 sizeof(*entry), flags, pc);
37 if (!event)
38 return;
39 entry = ring_buffer_event_data(event);
40 entry->prev_pid = prev->pid;
41 entry->prev_prio = prev->prio;
42 entry->prev_state = prev->state;
43 entry->next_pid = next->pid;
44 entry->next_prio = next->prio;
45 entry->next_state = next->state;
46 entry->next_cpu = task_cpu(next);
47
48 if (!call_filter_check_discard(call, entry, buffer, event))
49 trace_buffer_unlock_commit(buffer, event, flags, pc);
50}
51
52static void
53probe_sched_switch(void *ignore, struct task_struct *prev, struct task_struct *next)
54{
55 struct trace_array_cpu *data;
56 unsigned long flags;
57 int cpu;
58 int pc;
59
60 if (unlikely(!sched_ref))
61 return;
62
63 tracing_record_cmdline(prev);
64 tracing_record_cmdline(next);
65
66 if (!tracer_enabled || sched_stopped)
67 return;
68
69 pc = preempt_count();
70 local_irq_save(flags);
71 cpu = raw_smp_processor_id();
72 data = per_cpu_ptr(ctx_trace->trace_buffer.data, cpu);
73
74 if (likely(!atomic_read(&data->disabled)))
75 tracing_sched_switch_trace(ctx_trace, prev, next, flags, pc);
76
77 local_irq_restore(flags);
78}
79
80void
81tracing_sched_wakeup_trace(struct trace_array *tr,
82 struct task_struct *wakee,
83 struct task_struct *curr,
84 unsigned long flags, int pc)
85{
86 struct ftrace_event_call *call = &event_wakeup;
87 struct ring_buffer_event *event;
88 struct ctx_switch_entry *entry;
89 struct ring_buffer *buffer = tr->trace_buffer.buffer;
90
91 event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
92 sizeof(*entry), flags, pc);
93 if (!event)
94 return;
95 entry = ring_buffer_event_data(event);
96 entry->prev_pid = curr->pid;
97 entry->prev_prio = curr->prio;
98 entry->prev_state = curr->state;
99 entry->next_pid = wakee->pid;
100 entry->next_prio = wakee->prio;
101 entry->next_state = wakee->state;
102 entry->next_cpu = task_cpu(wakee);
103
104 if (!call_filter_check_discard(call, entry, buffer, event))
105 trace_buffer_unlock_commit(buffer, event, flags, pc);
106}
107
108static void
109probe_sched_wakeup(void *ignore, struct task_struct *wakee, int success)
110{
111 struct trace_array_cpu *data;
112 unsigned long flags;
113 int cpu, pc;
114
115 if (unlikely(!sched_ref))
116 return;
117
118 tracing_record_cmdline(current);
119
120 if (!tracer_enabled || sched_stopped)
121 return;
122
123 pc = preempt_count();
124 local_irq_save(flags);
125 cpu = raw_smp_processor_id();
126 data = per_cpu_ptr(ctx_trace->trace_buffer.data, cpu);
127
128 if (likely(!atomic_read(&data->disabled)))
129 tracing_sched_wakeup_trace(ctx_trace, wakee, current,
130 flags, pc);
131
132 local_irq_restore(flags);
133}
134
135static int tracing_sched_register(void)
136{
137 int ret;
138
139 ret = register_trace_sched_wakeup(probe_sched_wakeup, NULL);
140 if (ret) {
141 pr_info("wakeup trace: Couldn't activate tracepoint"
142 " probe to kernel_sched_wakeup\n");
143 return ret;
144 }
145
146 ret = register_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
147 if (ret) {
148 pr_info("wakeup trace: Couldn't activate tracepoint"
149 " probe to kernel_sched_wakeup_new\n");
150 goto fail_deprobe;
151 }
152
153 ret = register_trace_sched_switch(probe_sched_switch, NULL);
154 if (ret) {
155 pr_info("sched trace: Couldn't activate tracepoint"
156 " probe to kernel_sched_switch\n");
157 goto fail_deprobe_wake_new;
158 }
159
160 return ret;
161fail_deprobe_wake_new:
162 unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
163fail_deprobe:
164 unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
165 return ret;
166}
167
168static void tracing_sched_unregister(void)
169{
170 unregister_trace_sched_switch(probe_sched_switch, NULL);
171 unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
172 unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
173}
174
175static void tracing_start_sched_switch(void)
176{
177 mutex_lock(&sched_register_mutex);
178 if (!(sched_ref++))
179 tracing_sched_register();
180 mutex_unlock(&sched_register_mutex);
181}
182
183static void tracing_stop_sched_switch(void)
184{
185 mutex_lock(&sched_register_mutex);
186 if (!(--sched_ref))
187 tracing_sched_unregister();
188 mutex_unlock(&sched_register_mutex);
189}
190
191void tracing_start_cmdline_record(void)
192{
193 tracing_start_sched_switch();
194}
195
196void tracing_stop_cmdline_record(void)
197{
198 tracing_stop_sched_switch();
199}
200
201/**
202 * tracing_start_sched_switch_record - start tracing context switches
203 *
204 * Turns on context switch tracing for a tracer.
205 */
206void tracing_start_sched_switch_record(void)
207{
208 if (unlikely(!ctx_trace)) {
209 WARN_ON(1);
210 return;
211 }
212
213 tracing_start_sched_switch();
214
215 mutex_lock(&sched_register_mutex);
216 tracer_enabled++;
217 mutex_unlock(&sched_register_mutex);
218}
219
220/**
221 * tracing_stop_sched_switch_record - start tracing context switches
222 *
223 * Turns off context switch tracing for a tracer.
224 */
225void tracing_stop_sched_switch_record(void)
226{
227 mutex_lock(&sched_register_mutex);
228 tracer_enabled--;
229 WARN_ON(tracer_enabled < 0);
230 mutex_unlock(&sched_register_mutex);
231
232 tracing_stop_sched_switch();
233}
234
235/**
236 * tracing_sched_switch_assign_trace - assign a trace array for ctx switch
237 * @tr: trace array pointer to assign
238 *
239 * Some tracers might want to record the context switches in their
240 * trace. This function lets those tracers assign the trace array
241 * to use.
242 */
243void tracing_sched_switch_assign_trace(struct trace_array *tr)
244{
245 ctx_trace = tr;
246}
247