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 | |
19 | static int sched_cmdline_ref; |
20 | static int sched_tgid_ref; |
21 | static DEFINE_MUTEX(sched_register_mutex); |
22 | |
23 | static void |
24 | probe_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 | |
38 | static void |
39 | probe_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, next: wakee, flags); |
49 | } |
50 | |
51 | static int tracing_sched_register(void) |
52 | { |
53 | int ret; |
54 | |
55 | ret = register_trace_sched_wakeup(probe: 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: 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: 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; |
77 | fail_deprobe_wake_new: |
78 | unregister_trace_sched_wakeup_new(probe: probe_sched_wakeup, NULL); |
79 | fail_deprobe: |
80 | unregister_trace_sched_wakeup(probe: probe_sched_wakeup, NULL); |
81 | return ret; |
82 | } |
83 | |
84 | static void tracing_sched_unregister(void) |
85 | { |
86 | unregister_trace_sched_switch(probe: probe_sched_switch, NULL); |
87 | unregister_trace_sched_wakeup_new(probe: probe_sched_wakeup, NULL); |
88 | unregister_trace_sched_wakeup(probe: probe_sched_wakeup, NULL); |
89 | } |
90 | |
91 | static 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(lock: &sched_register_mutex); |
111 | } |
112 | |
113 | static 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(lock: &sched_register_mutex); |
130 | } |
131 | |
132 | void tracing_start_cmdline_record(void) |
133 | { |
134 | tracing_start_sched_switch(RECORD_CMDLINE); |
135 | } |
136 | |
137 | void tracing_stop_cmdline_record(void) |
138 | { |
139 | tracing_stop_sched_switch(RECORD_CMDLINE); |
140 | } |
141 | |
142 | void tracing_start_tgid_record(void) |
143 | { |
144 | tracing_start_sched_switch(RECORD_TGID); |
145 | } |
146 | |
147 | void tracing_stop_tgid_record(void) |
148 | { |
149 | tracing_stop_sched_switch(RECORD_TGID); |
150 | } |
151 | |