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 "gcov.h"
  22
  23static struct gcov_info *gcov_info_head;
  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 = info->version;
  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        info->next = gcov_info_head;
  49        gcov_info_head = info;
  50        if (gcov_events_enabled)
  51                gcov_event(GCOV_ADD, info);
  52        mutex_unlock(&gcov_lock);
  53}
  54EXPORT_SYMBOL(__gcov_init);
  55
  56/*
  57 * These functions may be referenced by gcc-generated profiling code but serve
  58 * no function for kernel profiling.
  59 */
  60void __gcov_flush(void)
  61{
  62        /* Unused. */
  63}
  64EXPORT_SYMBOL(__gcov_flush);
  65
  66void __gcov_merge_add(gcov_type *counters, unsigned int n_counters)
  67{
  68        /* Unused. */
  69}
  70EXPORT_SYMBOL(__gcov_merge_add);
  71
  72void __gcov_merge_single(gcov_type *counters, unsigned int n_counters)
  73{
  74        /* Unused. */
  75}
  76EXPORT_SYMBOL(__gcov_merge_single);
  77
  78void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters)
  79{
  80        /* Unused. */
  81}
  82EXPORT_SYMBOL(__gcov_merge_delta);
  83
  84/**
  85 * gcov_enable_events - enable event reporting through gcov_event()
  86 *
  87 * Turn on reporting of profiling data load/unload-events through the
  88 * gcov_event() callback. Also replay all previous events once. This function
  89 * is needed because some events are potentially generated too early for the
  90 * callback implementation to handle them initially.
  91 */
  92void gcov_enable_events(void)
  93{
  94        struct gcov_info *info;
  95
  96        mutex_lock(&gcov_lock);
  97        gcov_events_enabled = 1;
  98        /* Perform event callback for previously registered entries. */
  99        for (info = gcov_info_head; info; info = info->next)
 100                gcov_event(GCOV_ADD, info);
 101        mutex_unlock(&gcov_lock);
 102}
 103
 104#ifdef CONFIG_MODULES
 105static inline int within(void *addr, void *start, unsigned long size)
 106{
 107        return ((addr >= start) && (addr < start + size));
 108}
 109
 110/* Update list and generate events when modules are unloaded. */
 111static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
 112                                void *data)
 113{
 114        struct module *mod = data;
 115        struct gcov_info *info;
 116        struct gcov_info *prev;
 117
 118        if (event != MODULE_STATE_GOING)
 119                return NOTIFY_OK;
 120        mutex_lock(&gcov_lock);
 121        prev = NULL;
 122        /* Remove entries located in module from linked list. */
 123        for (info = gcov_info_head; info; info = info->next) {
 124                if (within(info, mod->module_core, mod->core_size)) {
 125                        if (prev)
 126                                prev->next = info->next;
 127                        else
 128                                gcov_info_head = info->next;
 129                        if (gcov_events_enabled)
 130                                gcov_event(GCOV_REMOVE, info);
 131                } else
 132                        prev = info;
 133        }
 134        mutex_unlock(&gcov_lock);
 135
 136        return NOTIFY_OK;
 137}
 138
 139static struct notifier_block gcov_nb = {
 140        .notifier_call  = gcov_module_notifier,
 141};
 142
 143static int __init gcov_init(void)
 144{
 145        return register_module_notifier(&gcov_nb);
 146}
 147device_initcall(gcov_init);
 148#endif /* CONFIG_MODULES */
 149