| 1 | /* probe-example.c |
| 2 | * |
| 3 | * Connects a two functions to marker call sites. |
| 4 | * |
| 5 | * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> |
| 6 | * |
| 7 | * This file is released under the GPLv2. |
| 8 | * See the file COPYING for more details. |
| 9 | */ |
| 10 | |
| 11 | #include <linux/sched.h> |
| 12 | #include <linux/kernel.h> |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/marker.h> |
| 15 | #include <asm/atomic.h> |
| 16 | |
| 17 | #define NUM_PROBES (sizeof(probe_array) / sizeof(struct probe_data)) |
| 18 | |
| 19 | struct probe_data { |
| 20 | const char *name; |
| 21 | const char *format; |
| 22 | marker_probe_func *probe_func; |
| 23 | }; |
| 24 | |
| 25 | void probe_subsystem_event(const struct __mark_marker_c *mdata, |
| 26 | const char *format, ...) |
| 27 | { |
| 28 | va_list ap; |
| 29 | /* Declare args */ |
| 30 | unsigned int value; |
| 31 | const char *mystr; |
| 32 | int task_size, task_alignment; |
| 33 | struct task_struct *task; |
| 34 | |
| 35 | /* Assign args */ |
| 36 | va_start(ap, format); |
| 37 | value = va_arg(ap, typeof(value)); |
| 38 | mystr = va_arg(ap, typeof(mystr)); |
| 39 | task_size = va_arg(ap, typeof(task_size)); |
| 40 | task_alignment = va_arg(ap, typeof(task_alignment)); |
| 41 | task = va_arg(ap, typeof(task)); |
| 42 | |
| 43 | /* Call printk */ |
| 44 | printk("Value %u, string %s, current ptr %p\n", value, mystr, current); |
| 45 | |
| 46 | /* or count, check rights, serialize data in a buffer */ |
| 47 | |
| 48 | va_end(ap); |
| 49 | } |
| 50 | |
| 51 | atomic_t eventb_count = ATOMIC_INIT(0); |
| 52 | |
| 53 | void probe_subsystem_eventb(const struct __mark_marker_c *mdata, |
| 54 | const char *format, ...) |
| 55 | { |
| 56 | /* Increment counter */ |
| 57 | atomic_inc(&eventb_count); |
| 58 | } |
| 59 | |
| 60 | static struct probe_data probe_array[] = |
| 61 | { |
| 62 | { .name = "subsystem_event", |
| 63 | .format = "%d %s %*.*r", |
| 64 | .probe_func = probe_subsystem_event }, |
| 65 | { .name = "subsystem_eventb", |
| 66 | .format = MARK_NOARGS, |
| 67 | .probe_func = probe_subsystem_eventb }, |
| 68 | }; |
| 69 | |
| 70 | static int __init probe_init(void) |
| 71 | { |
| 72 | int result; |
| 73 | uint8_t eID; |
| 74 | |
| 75 | for (eID = 0; eID < NUM_PROBES; eID++) { |
| 76 | result = marker_set_probe(probe_array[eID].name, |
| 77 | probe_array[eID].format, |
| 78 | probe_array[eID].probe_func, &probe_array[eID]); |
| 79 | if (!result) |
| 80 | printk(KERN_INFO "Unable to register probe %s\n", |
| 81 | probe_array[eID].name); |
| 82 | } |
| 83 | return 0; |
| 84 | } |
| 85 | |
| 86 | static void __exit probe_fini(void) |
| 87 | { |
| 88 | uint8_t eID; |
| 89 | |
| 90 | for (eID = 0; eID < NUM_PROBES; eID++) { |
| 91 | marker_remove_probe(probe_array[eID].name); |
| 92 | } |
| 93 | synchronize_sched(); /* Wait for probes to finish */ |
| 94 | printk("Number of event b : %u\n", atomic_read(&eventb_count)); |
| 95 | } |
| 96 | |
| 97 | module_init(probe_init); |
| 98 | module_exit(probe_fini); |
| 99 | |
| 100 | MODULE_LICENSE("GPL"); |
| 101 | MODULE_AUTHOR("Mathieu Desnoyers"); |
| 102 | MODULE_DESCRIPTION("SUBSYSTEM Probe"); |