LXR linux/kernel/gcov/base.c

   1/*
   2 *  This code maintains a list of active profiling data structures.
   3 *
   4 *    Copyright IBM Corp. 2009
   5 *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
   6 *
   7 *    Uses gcc-internal data definitions.
   8 *    Based on the gcov-kernel patch by:
   9 *               Hubertus Franke <frankeh@us.ibm.com>
  10 *               Nigel Hinds <nhinds@us.ibm.com>
  11 *               Rajan Ravindran <rajancr@us.ibm.com>
  12 *               Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
  13 *               Paul Larson
  14 */
  15
  16#define pr_fmt(fmt)     "gcov: " fmt
  17
  18#include <linux/init.h>
  19#include <linux/module.h>
  20#include <linux/mutex.h>
  21#include <linux/sched.h>
  22#include "gcov.h"
  23
  24static int gcov_events_enabled;
  25static DEFINE_MUTEX(gcov_lock);
  26
  27/*
  28 * __gcov_init is called by gcc-generated constructor code for each object
  29 * file compiled with -fprofile-arcs.
  30 */
  31void __gcov_init(struct gcov_info *info)
  32{
  33        static unsigned int gcov_version;
  34
  35        mutex_lock(&gcov_lock);
  36        if (gcov_version == 0) {
  37                gcov_version = gcov_info_version(info);
  38                /*
  39                 * Printing gcc's version magic may prove useful for debugging
  40                 * incompatibility reports.
  41                 */
  42                pr_info("version magic: 0x%x\n", gcov_version);
  43        }
  44        /*
  45         * Add new profiling data structure to list and inform event
  46         * listener.
  47         */
  48        gcov_info_link(info);
  49        if (gcov_events_enabled)
  50                gcov_event(GCOV_ADD, info);
  51        mutex_unlock(&gcov_lock);
  52}
  53EXPORT_SYMBOL(__gcov_init);
  54
  55/*
  56 * These functions may be referenced by gcc-generated profiling code but serve
  57 * no function for kernel profiling.
  58 */
  59void __gcov_flush(void)
  60{
  61        /* Unused. */
  62}
  63EXPORT_SYMBOL(__gcov_flush);
  64
  65void __gcov_merge_add(gcov_type *counters, unsigned int n_counters)
  66{
  67        /* Unused. */
  68}
  69EXPORT_SYMBOL(__gcov_merge_add);
  70
  71void __gcov_merge_single(gcov_type *counters, unsigned int n_counters)
  72{
  73        /* Unused. */
  74}
  75EXPORT_SYMBOL(__gcov_merge_single);
  76
  77void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters)
  78{
  79        /* Unused. */
  80}
  81EXPORT_SYMBOL(__gcov_merge_delta);
  82
  83void __gcov_merge_ior(gcov_type *counters, unsigned int n_counters)
  84{
  85        /* Unused. */
  86}
  87EXPORT_SYMBOL(__gcov_merge_ior);
  88
  89void __gcov_merge_time_profile(gcov_type *counters, unsigned int n_counters)
  90{
  91        /* Unused. */
  92}
  93EXPORT_SYMBOL(__gcov_merge_time_profile);
  94
  95void __gcov_merge_icall_topn(gcov_type *counters, unsigned int n_counters)
  96{
  97        /* Unused. */
  98}
  99EXPORT_SYMBOL(__gcov_merge_icall_topn);
 100
 101/**
 102 * gcov_enable_events - enable event reporting through gcov_event()
 103 *
 104 * Turn on reporting of profiling data load/unload-events through the
 105 * gcov_event() callback. Also replay all previous events once. This function
 106 * is needed because some events are potentially generated too early for the
 107 * callback implementation to handle them initially.
 108 */
 109void gcov_enable_events(void)
 110{
 111        struct gcov_info *info = NULL;
 112
 113        mutex_lock(&gcov_lock);
 114        gcov_events_enabled = 1;
 115
 116        /* Perform event callback for previously registered entries. */
 117        while ((info = gcov_info_next(info))) {
 118                gcov_event(GCOV_ADD, info);
 119                cond_resched();
 120        }
 121
 122        mutex_unlock(&gcov_lock);
 123}
 124
 125#ifdef CONFIG_MODULES
 126/* Update list and generate events when modules are unloaded. */
 127static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
 128                                void *data)
 129{
 130        struct module *mod = data;
 131        struct gcov_info *info = NULL;
 132        struct gcov_info *prev = NULL;
 133
 134        if (event != MODULE_STATE_GOING)
 135                return NOTIFY_OK;
 136        mutex_lock(&gcov_lock);
 137
 138        /* Remove entries located in module from linked list. */
 139        while ((info = gcov_info_next(info))) {
 140                if (within_module((unsigned long)info, mod)) {
 141                        gcov_info_unlink(prev, info);
 142                        if (gcov_events_enabled)
 143                                gcov_event(GCOV_REMOVE, info);
 144                } else
 145                        prev = info;
 146        }
 147
 148        mutex_unlock(&gcov_lock);
 149
 150        return NOTIFY_OK;
 151}
 152
 153static struct notifier_block gcov_nb = {
 154        .notifier_call  = gcov_module_notifier,
 155};
 156
 157static int __init gcov_init(void)
 158{
 159        return register_module_notifier(&gcov_nb);
 160}
 161device_initcall(gcov_init);
 162#endif /* CONFIG_MODULES */
 163