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
95/**
96 * gcov_enable_events - enable event reporting through gcov_event()
97 *
98 * Turn on reporting of profiling data load/unload-events through the
99 * gcov_event() callback. Also replay all previous events once. This function
100 * is needed because some events are potentially generated too early for the
101 * callback implementation to handle them initially.
102 */
103void gcov_enable_events(void)
104{
105	struct gcov_info *info = NULL;
106
107	mutex_lock(&gcov_lock);
108	gcov_events_enabled = 1;
109
110	/* Perform event callback for previously registered entries. */
111	while ((info = gcov_info_next(info))) {
112		gcov_event(GCOV_ADD, info);
113		cond_resched();
114	}
115
116	mutex_unlock(&gcov_lock);
117}
118
119#ifdef CONFIG_MODULES
120static inline int within(void *addr, void *start, unsigned long size)
121{
122	return ((addr >= start) && (addr < start + size));
123}
124
125/* Update list and generate events when modules are unloaded. */
126static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
127				void *data)
128{
129	struct module *mod = data;
130	struct gcov_info *info = NULL;
131	struct gcov_info *prev = NULL;
132
133	if (event != MODULE_STATE_GOING)
134		return NOTIFY_OK;
135	mutex_lock(&gcov_lock);
136
137	/* Remove entries located in module from linked list. */
138	while ((info = gcov_info_next(info))) {
139		if (within(info, mod->module_core, mod->core_size)) {
140			gcov_info_unlink(prev, info);
141			if (gcov_events_enabled)
142				gcov_event(GCOV_REMOVE, info);
143		} else
144			prev = info;
145	}
146
147	mutex_unlock(&gcov_lock);
148
149	return NOTIFY_OK;
150}
151
152static struct notifier_block gcov_nb = {
153	.notifier_call	= gcov_module_notifier,
154};
155
156static int __init gcov_init(void)
157{
158	return register_module_notifier(&gcov_nb);
159}
160device_initcall(gcov_init);
161#endif /* CONFIG_MODULES */
162