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
23 static struct gcov_info *gcov_info_head;
24 static int gcov_events_enabled;
25 static 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 */
__gcov_init(struct gcov_info * info)31 void __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 }
54 EXPORT_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 */
__gcov_flush(void)60 void __gcov_flush(void)
61 {
62 /* Unused. */
63 }
64 EXPORT_SYMBOL(__gcov_flush);
65
__gcov_merge_add(gcov_type * counters,unsigned int n_counters)66 void __gcov_merge_add(gcov_type *counters, unsigned int n_counters)
67 {
68 /* Unused. */
69 }
70 EXPORT_SYMBOL(__gcov_merge_add);
71
__gcov_merge_single(gcov_type * counters,unsigned int n_counters)72 void __gcov_merge_single(gcov_type *counters, unsigned int n_counters)
73 {
74 /* Unused. */
75 }
76 EXPORT_SYMBOL(__gcov_merge_single);
77
__gcov_merge_delta(gcov_type * counters,unsigned int n_counters)78 void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters)
79 {
80 /* Unused. */
81 }
82 EXPORT_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 */
gcov_enable_events(void)92 void 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
within(void * addr,void * start,unsigned long size)105 static 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. */
gcov_module_notifier(struct notifier_block * nb,unsigned long event,void * data)111 static 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
139 static struct notifier_block gcov_nb = {
140 .notifier_call = gcov_module_notifier,
141 };
142
gcov_init(void)143 static int __init gcov_init(void)
144 {
145 return register_module_notifier(&gcov_nb);
146 }
147 device_initcall(gcov_init);
148 #endif /* CONFIG_MODULES */
149