markers-userspace/marker-lib.c

   1
   2 #include "marker.h"
   3 #include <stdio.h>
   4 #include <errno.h>
   5
   6 __attribute__ ((visibility ("protected"))) extern struct marker __start___markers[];
   7 __attribute__ ((visibility ("protected"))) 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 __attribute__ ((visibility ("protected")))
  22 void __mark_empty_function(void *probe_private, void *call_private,
  23         const char *fmt, va_list *args)
  24 {
  25 }
  26
  27 /*
  28  * marker_probe_cb Callback that prepares the variable argument list for probes.
  29  * @mdata: pointer of type struct marker
  30  * @call_private: caller site private data
  31  * @fmt: format string
  32  * @...:  Variable argument list.
  33  *
  34  */
  35 __attribute__ ((visibility ("protected")))
  36 void marker_probe_cb(const struct marker *mdata, void *call_private,
  37         const char *fmt, ...)
  38 {
  39         static unsigned int count = 0;
  40
  41         printf("Test probe function %u\n", count++);
  42 }
  43
  44 //FIXME : imv_read won't work with optimized immediate values.
  45 //will need to issue one sys_marker call for each immediate value.
  46 __attribute__ ((visibility ("protected")))
  47 void testip(void)
  48 {
  49         printf("addr : %p\n", __builtin_return_address(0));
  50 }
  51
  52 __attribute__((constructor, visibility ("protected"))) void marker_init(void)
  53 {
  54         struct marker *iter;
  55         int ret;
  56
  57         printf("Marker section : from %p to %p (init)\n",
  58                 __start___markers, __stop___markers);
  59         testip();
  60         for (iter = __start___markers; iter < __stop___markers; iter++) {
  61                 printf("Marker : %s\n", iter->name);
  62                 ret = sys_marker(iter->name, iter->format,
  63                         &imv_read(iter->state), 1);
  64                 if (ret)
  65                         perror("Error connecting markers");
  66         }
  67 }
  68
  69 static __attribute__((destructor, visibility ("protected"))) void marker_fini(void)
  70 {
  71         struct marker *iter;
  72         int ret;
  73
  74         printf("Marker section : from %p to %p (fini)\n",
  75                 __start___markers, __stop___markers);
  76         for (iter = __start___markers; iter < __stop___markers; iter++) {
  77                 printf("Marker : %s\n", iter->name);
  78                 ret = sys_marker(iter->name, iter->format,
  79                         &imv_read(iter->state), 0);
  80                 if (ret)
  81                         perror("Error disconnecting markers");
  82         }
  83 }