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 //FIXME : imv_read won't work with optimized immediate values.
  43 //will need to issue one sys_marker call for each immediate value.
  44
  45 __attribute__((constructor)) void marker_init(void)
  46 {
  47         struct marker *iter;
  48         int ret;
  49
  50         printf("Marker section : from %p to %p (init)\n",
  51                 __start___markers, __stop___markers);
  52         for (iter = __start___markers; iter < __stop___markers; iter++) {
  53                 printf("Marker : %s\n", iter->name);
  54                 ret = sys_marker(iter->name, iter->format,
  55                         &imv_read(iter->state), 1);
  56                 if (ret)
  57                         perror("Error connecting markers");
  58         }
  59 }
  60
  61 __attribute__((destructor)) void marker_fini(void)
  62 {
  63         struct marker *iter;
  64         int ret;
  65
  66         printf("Marker section : from %p to %p (fini)\n",
  67                 __start___markers, __stop___markers);
  68         for (iter = __start___markers; iter < __stop___markers; iter++) {
  69                 printf("Marker : %s\n", iter->name);
  70                 ret = sys_marker(iter->name, iter->format,
  71                         &imv_read(iter->state), 0);
  72                 if (ret)
  73                         perror("Error disconnecting markers");
  74         }
  75 }