tests/kernel/probe.c

   1 /* probe.c
   2  *
   3  * Loads a function at a marker call site.
   4  *
   5  * (C) Copyright 2006 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/marker.h>
  12 #include <linux/module.h>
  13 #include <linux/kallsyms.h>
  14
  15 /* function to install */
  16 #define DO_MARK1_FORMAT "%d"
  17 asmlinkage void do_mark1(const char *format, int value)
  18 {
  19         __mark_check_format(DO_MARK1_FORMAT, value);
  20         printk("value is %d\n", value);
  21 }
  22
  23 #define DO_MARK2_FORMAT "%d %s"
  24 asmlinkage void do_mark2(const char *format, int value, const char *string)
  25 {
  26         __mark_check_format(DO_MARK2_FORMAT, value, string);
  27         printk("value is %d %s\n", value, string);
  28 }
  29
  30 #define DO_MARK3_FORMAT "%d %s %s"
  31 asmlinkage void do_mark3(const char *format, int value, const char *s1,
  32                                 const char *s2)
  33 {
  34         __mark_check_format(DO_MARK3_FORMAT, value, s1, s2);
  35         printk("value is %d %s %s\n", value, s1, s2);
  36 }
  37
  38 int init_module(void)
  39 {
  40         int result;
  41         result = marker_set_probe("subsys_mark1", DO_MARK1_FORMAT,
  42                         (marker_probe_func*)do_mark1);
  43         if(result) goto end;
  44         result = marker_set_probe("subsys_mark2", DO_MARK2_FORMAT,
  45                         (marker_probe_func*)do_mark2);
  46         if(result) goto cleanup1;
  47         result = marker_set_probe("subsys_mark3", DO_MARK3_FORMAT,
  48                         (marker_probe_func*)do_mark3);
  49         if(result) goto cleanup2;
  50
  51         return -result;
  52
  53 cleanup2:
  54         marker_disable_probe("subsys_mark2", (marker_probe_func*)do_mark2);
  55 cleanup1:
  56         marker_disable_probe("subsys_mark1", (marker_probe_func*)do_mark1);
  57 end:
  58         return -result;
  59 }
  60
  61 void cleanup_module(void)
  62 {
  63         marker_disable_probe("subsys_mark1", (marker_probe_func*)do_mark1);
  64         marker_disable_probe("subsys_mark2", (marker_probe_func*)do_mark2);
  65         marker_disable_probe("subsys_mark3", (marker_probe_func*)do_mark3);
  66 }
  67
  68 MODULE_LICENSE("GPL");
  69 MODULE_AUTHOR("Mathieu Desnoyers");
  70 MODULE_DESCRIPTION("Probe");
  71