cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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trace-events-sample.c (3034B)

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