/* probe-example.c * * Connects two functions to marker call sites. * * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> * * This file is released under the GPLv2. * See the file COPYING for more details. */ #include <linux/sched.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/marker.h> #include <asm/atomic.h> struct probe_data { const char *name; const char *format; marker_probe_func *probe_func; }; void probe_subsystem_event(void *probe_data, void *call_data, const char *format, va_list *args) { /* Declare args */ unsigned int value; const char *mystr; /* Assign args */ value = va_arg(*args, typeof(value)); mystr = va_arg(*args, typeof(mystr)); /* Call printk */ printk(KERN_INFO "Value %u, string %s\n", value, mystr); /* or count, check rights, serialize data in a buffer */ } atomic_t eventb_count = ATOMIC_INIT(0); void probe_subsystem_eventb(void *probe_data, void *call_data, const char *format, va_list *args) { /* Increment counter */ atomic_inc(&eventb_count); } static struct probe_data probe_array[] = { { .name = "subsystem_event", .format = "integer %d string %s", .probe_func = probe_subsystem_event }, { .name = "subsystem_eventb", .format = MARK_NOARGS, .probe_func = probe_subsystem_eventb }, }; static int __init probe_init(void) { int result; int i; for (i = 0; i < ARRAY_SIZE(probe_array); i++) { result = marker_probe_register(probe_array[i].name, probe_array[i].format, probe_array[i].probe_func, &probe_array[i]); if (result) printk(KERN_INFO "Unable to register probe %s\n", probe_array[i].name); } return 0; } static void __exit probe_fini(void) { int i; for (i = 0; i < ARRAY_SIZE(probe_array); i++) marker_probe_unregister(probe_array[i].name, probe_array[i].probe_func, &probe_array[i]); printk(KERN_INFO "Number of event b : %u\n", atomic_read(&eventb_count)); marker_synchronize_unregister(); } module_init(probe_init); module_exit(probe_fini); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Mathieu Desnoyers"); MODULE_DESCRIPTION("SUBSYSTEM Probe");