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140 lines
2.9 KiB
140 lines
2.9 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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#include <linux/module.h> |
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#include <linux/kthread.h> |
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/* |
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* Any file that uses trace points, must include the header. |
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* But only one file, must include the header by defining |
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* CREATE_TRACE_POINTS first. This will make the C code that |
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* creates the handles for the trace points. |
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*/ |
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#define CREATE_TRACE_POINTS |
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#include "trace-events-sample.h" |
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static const char *random_strings[] = { |
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"Mother Goose", |
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"Snoopy", |
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"Gandalf", |
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"Frodo", |
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"One ring to rule them all" |
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}; |
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static void simple_thread_func(int cnt) |
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{ |
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int array[6]; |
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int len = cnt % 5; |
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int i; |
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set_current_state(TASK_INTERRUPTIBLE); |
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schedule_timeout(HZ); |
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for (i = 0; i < len; i++) |
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array[i] = i + 1; |
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array[i] = 0; |
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/* Silly tracepoints */ |
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trace_foo_bar("hello", cnt, array, random_strings[len], |
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current->cpus_ptr); |
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trace_foo_with_template_simple("HELLO", cnt); |
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trace_foo_bar_with_cond("Some times print", cnt); |
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trace_foo_with_template_cond("prints other times", cnt); |
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trace_foo_with_template_print("I have to be different", cnt); |
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} |
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static int simple_thread(void *arg) |
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{ |
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int cnt = 0; |
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while (!kthread_should_stop()) |
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simple_thread_func(cnt++); |
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return 0; |
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} |
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static struct task_struct *simple_tsk; |
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static struct task_struct *simple_tsk_fn; |
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static void simple_thread_func_fn(int cnt) |
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{ |
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set_current_state(TASK_INTERRUPTIBLE); |
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schedule_timeout(HZ); |
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/* More silly tracepoints */ |
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trace_foo_bar_with_fn("Look at me", cnt); |
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trace_foo_with_template_fn("Look at me too", cnt); |
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} |
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static int simple_thread_fn(void *arg) |
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{ |
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int cnt = 0; |
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while (!kthread_should_stop()) |
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simple_thread_func_fn(cnt++); |
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return 0; |
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} |
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static DEFINE_MUTEX(thread_mutex); |
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static int simple_thread_cnt; |
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int foo_bar_reg(void) |
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{ |
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mutex_lock(&thread_mutex); |
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if (simple_thread_cnt++) |
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goto out; |
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pr_info("Starting thread for foo_bar_fn\n"); |
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/* |
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* We shouldn't be able to start a trace when the module is |
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* unloading (there's other locks to prevent that). But |
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* for consistency sake, we still take the thread_mutex. |
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*/ |
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simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn"); |
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out: |
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mutex_unlock(&thread_mutex); |
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return 0; |
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} |
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void foo_bar_unreg(void) |
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{ |
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mutex_lock(&thread_mutex); |
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if (--simple_thread_cnt) |
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goto out; |
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pr_info("Killing thread for foo_bar_fn\n"); |
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if (simple_tsk_fn) |
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kthread_stop(simple_tsk_fn); |
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simple_tsk_fn = NULL; |
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out: |
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mutex_unlock(&thread_mutex); |
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} |
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static int __init trace_event_init(void) |
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{ |
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simple_tsk = kthread_run(simple_thread, NULL, "event-sample"); |
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if (IS_ERR(simple_tsk)) |
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return -1; |
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return 0; |
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} |
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static void __exit trace_event_exit(void) |
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{ |
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kthread_stop(simple_tsk); |
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mutex_lock(&thread_mutex); |
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if (simple_tsk_fn) |
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kthread_stop(simple_tsk_fn); |
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simple_tsk_fn = NULL; |
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mutex_unlock(&thread_mutex); |
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} |
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module_init(trace_event_init); |
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module_exit(trace_event_exit); |
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MODULE_AUTHOR("Steven Rostedt"); |
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MODULE_DESCRIPTION("trace-events-sample"); |
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MODULE_LICENSE("GPL");
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