1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | #include <linux/module.h> |
3 | #include <linux/kthread.h> |
4 | |
5 | /* |
6 | * Any file that uses trace points, must include the header. |
7 | * But only one file, must include the header by defining |
8 | * CREATE_TRACE_POINTS first. This will make the C code that |
9 | * creates the handles for the trace points. |
10 | */ |
11 | #define CREATE_TRACE_POINTS |
12 | #include "trace-events-sample.h" |
13 | |
14 | static const char *random_strings[] = { |
15 | "Mother Goose" , |
16 | "Snoopy" , |
17 | "Gandalf" , |
18 | "Frodo" , |
19 | "One ring to rule them all" |
20 | }; |
21 | |
22 | static void do_simple_thread_func(int cnt, const char *fmt, ...) |
23 | { |
24 | unsigned long bitmask[1] = {0xdeadbeefUL}; |
25 | va_list va; |
26 | int array[6]; |
27 | int len = cnt % 5; |
28 | int i; |
29 | |
30 | set_current_state(TASK_INTERRUPTIBLE); |
31 | schedule_timeout(HZ); |
32 | |
33 | for (i = 0; i < len; i++) |
34 | array[i] = i + 1; |
35 | array[i] = 0; |
36 | |
37 | va_start(va, fmt); |
38 | |
39 | /* Silly tracepoints */ |
40 | trace_foo_bar(foo: "hello" , bar: cnt, lst: array, string: random_strings[len], |
41 | current->cpus_ptr, fmt, va: &va); |
42 | |
43 | va_end(va); |
44 | |
45 | trace_foo_with_template_simple(foo: "HELLO" , bar: cnt); |
46 | |
47 | trace_foo_bar_with_cond(foo: "Some times print" , bar: cnt); |
48 | |
49 | trace_foo_with_template_cond(foo: "prints other times" , bar: cnt); |
50 | |
51 | trace_foo_with_template_print(foo: "I have to be different" , bar: cnt); |
52 | |
53 | trace_foo_rel_loc(foo: "Hello __rel_loc" , bar: cnt, mask: bitmask, current->cpus_ptr); |
54 | } |
55 | |
56 | static void simple_thread_func(int cnt) |
57 | { |
58 | do_simple_thread_func(cnt, fmt: "iter=%d" , cnt); |
59 | } |
60 | |
61 | static int simple_thread(void *arg) |
62 | { |
63 | int cnt = 0; |
64 | |
65 | while (!kthread_should_stop()) |
66 | simple_thread_func(cnt: cnt++); |
67 | |
68 | return 0; |
69 | } |
70 | |
71 | static struct task_struct *simple_tsk; |
72 | static struct task_struct *simple_tsk_fn; |
73 | |
74 | static void simple_thread_func_fn(int cnt) |
75 | { |
76 | set_current_state(TASK_INTERRUPTIBLE); |
77 | schedule_timeout(HZ); |
78 | |
79 | /* More silly tracepoints */ |
80 | trace_foo_bar_with_fn(foo: "Look at me" , bar: cnt); |
81 | trace_foo_with_template_fn(foo: "Look at me too" , bar: cnt); |
82 | } |
83 | |
84 | static int simple_thread_fn(void *arg) |
85 | { |
86 | int cnt = 0; |
87 | |
88 | while (!kthread_should_stop()) |
89 | simple_thread_func_fn(cnt: cnt++); |
90 | |
91 | return 0; |
92 | } |
93 | |
94 | static DEFINE_MUTEX(thread_mutex); |
95 | static int simple_thread_cnt; |
96 | |
97 | int foo_bar_reg(void) |
98 | { |
99 | mutex_lock(&thread_mutex); |
100 | if (simple_thread_cnt++) |
101 | goto out; |
102 | |
103 | pr_info("Starting thread for foo_bar_fn\n" ); |
104 | /* |
105 | * We shouldn't be able to start a trace when the module is |
106 | * unloading (there's other locks to prevent that). But |
107 | * for consistency sake, we still take the thread_mutex. |
108 | */ |
109 | simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn" ); |
110 | out: |
111 | mutex_unlock(lock: &thread_mutex); |
112 | return 0; |
113 | } |
114 | |
115 | void foo_bar_unreg(void) |
116 | { |
117 | mutex_lock(&thread_mutex); |
118 | if (--simple_thread_cnt) |
119 | goto out; |
120 | |
121 | pr_info("Killing thread for foo_bar_fn\n" ); |
122 | if (simple_tsk_fn) |
123 | kthread_stop(k: simple_tsk_fn); |
124 | simple_tsk_fn = NULL; |
125 | out: |
126 | mutex_unlock(lock: &thread_mutex); |
127 | } |
128 | |
129 | static int __init trace_event_init(void) |
130 | { |
131 | simple_tsk = kthread_run(simple_thread, NULL, "event-sample" ); |
132 | if (IS_ERR(ptr: simple_tsk)) |
133 | return -1; |
134 | |
135 | return 0; |
136 | } |
137 | |
138 | static void __exit trace_event_exit(void) |
139 | { |
140 | kthread_stop(k: simple_tsk); |
141 | mutex_lock(&thread_mutex); |
142 | if (simple_tsk_fn) |
143 | kthread_stop(k: simple_tsk_fn); |
144 | simple_tsk_fn = NULL; |
145 | mutex_unlock(lock: &thread_mutex); |
146 | } |
147 | |
148 | module_init(trace_event_init); |
149 | module_exit(trace_event_exit); |
150 | |
151 | MODULE_AUTHOR("Steven Rostedt" ); |
152 | MODULE_DESCRIPTION("trace-events-sample" ); |
153 | MODULE_LICENSE("GPL" ); |
154 | |