markers-userspace/marker-lib.c

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