markers-userspace/marker-lib.c

   1
   2 #include "marker.h"
   3 #include <stdio.h>
   4 #include <errno.h>
   5
   6 extern struct marker __start___markers[];
   7 extern struct marker __stop___markers[];
   8
   9 /**
  10  * __mark_empty_function - Empty probe callback
  11  * @probe_private: probe private data
  12  * @call_private: call site private data
  13  * @fmt: format string
  14  * @...: variable argument list
  15  *
  16  * Empty callback provided as a probe to the markers. By providing this to a
  17  * disabled marker, we make sure the  execution flow is always valid even
  18  * though the function pointer change and the marker enabling are two distinct
  19  * operations that modifies the execution flow of preemptible code.
  20  */
  21 void __mark_empty_function(void *probe_private, void *call_private,
  22         const char *fmt, va_list *args)
  23 {
  24 }
  25
  26 /*
  27  * marker_probe_cb Callback that prepares the variable argument list for probes.
  28  * @mdata: pointer of type struct marker
  29  * @call_private: caller site private data
  30  * @fmt: format string
  31  * @...:  Variable argument list.
  32  *
  33  */
  34 void marker_probe_cb(const struct marker *mdata, void *call_private,
  35         const char *fmt, ...)
  36 {
  37         static unsigned int count = 0;
  38
  39         printf("Test probe function %u\n", count++);
  40 }
  41
  42 __attribute__((constructor)) void marker_init(void)
  43 {
  44         struct marker *iter;
  45         int ret;
  46
  47         printf("Marker section : from %p to %p\n",
  48                 __start___markers, __stop___markers);
  49         ret = sys_marker(__start___markers, __stop___markers);
  50         if (ret)
  51                 perror("Error connecting markers");
  52         for (iter = __start___markers; iter < __stop___markers; iter++) {
  53                 printf("Marker : %s\n", iter->name);
  54         }
  55 }