markers-userspace/marker-lib.c

   1
   2 #include "marker.h"
   3 #include <stdio.h>
   4 #include <errno.h>
   5 #include <sys/user.h>
   6
   7 __attribute__ ((visibility ("protected")))
   8 extern struct marker __start___markers[];
   9
  10 __attribute__ ((visibility ("protected")))
  11 extern struct marker __stop___markers[];
  12
  13 /**
  14  * __mark_empty_function - Empty probe callback
  15  * @probe_private: probe private data
  16  * @call_private: call site private data
  17  * @fmt: format string
  18  * @...: variable argument list
  19  *
  20  * Empty callback provided as a probe to the markers. By providing this to a
  21  * disabled marker, we make sure the  execution flow is always valid even
  22  * though the function pointer change and the marker enabling are two distinct
  23  * operations that modifies the execution flow of preemptible code.
  24  */
  25 __attribute__ ((visibility ("protected")))
  26 void __mark_empty_function(void *probe_private, void *call_private,
  27         const char *fmt, va_list *args)
  28 {
  29 }
  30
  31 /*
  32  * marker_probe_cb Callback that prepares the variable argument list for probes.
  33  * @mdata: pointer of type struct marker
  34  * @call_private: caller site private data
  35  * @fmt: format string
  36  * @...:  Variable argument list.
  37  *
  38  */
  39 __attribute__ ((visibility ("protected")))
  40 void marker_probe_cb(const struct marker *mdata, void *call_private,
  41         const char *fmt, ...)
  42 {
  43         char buf[PAGE_SIZE];
  44         va_list ap;
  45
  46         va_start(ap, fmt);
  47         vsnprintf(buf, PAGE_SIZE-1, fmt, ap);
  48         sys_trace(0, 0, buf);
  49         va_end(ap);
  50 }
  51
  52 //FIXME : imv_read won't work with optimized immediate values.
  53 //will need to issue one sys_marker call for each immediate value.
  54 __attribute__ ((visibility ("protected")))
  55 void testip(void)
  56 {
  57         printf("addr : %p\n", __builtin_return_address(0));
  58 }
  59
  60 __attribute__((constructor, visibility ("protected")))
  61 void marker_init(void)
  62 {
  63         struct marker *iter;
  64         int ret;
  65
  66         printf("Marker section : from %p to %p (init)\n",
  67                 __start___markers, __stop___markers);
  68         testip();
  69         for (iter = __start___markers; iter < __stop___markers; iter++) {
  70                 printf("Marker : %s\n", iter->name);
  71                 ret = sys_marker(iter->name, iter->format,
  72                         &imv_read(iter->state), 1);
  73                 if (ret)
  74                         perror("Error connecting markers");
  75         }
  76 }
  77
  78 __attribute__((destructor, visibility ("protected")))
  79 void marker_fini(void)
  80 {
  81         struct marker *iter;
  82         int ret;
  83
  84         printf("Marker section : from %p to %p (fini)\n",
  85                 __start___markers, __stop___markers);
  86         for (iter = __start___markers; iter < __stop___markers; iter++) {
  87                 printf("Marker : %s\n", iter->name);
  88                 ret = sys_marker(iter->name, iter->format,
  89                         &imv_read(iter->state), 0);
  90                 if (ret)
  91                         perror("Error disconnecting markers");
  92         }
  93 }