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 int gcov_events_enabled;
24static DEFINE_MUTEX(gcov_lock);
25
26/*
27 * __gcov_init is called by gcc-generated constructor code for each object
28 * file compiled with -fprofile-arcs.
29 */
30void __gcov_init(struct gcov_info *info)
31{
32	static unsigned int gcov_version;
33
34	mutex_lock(&gcov_lock);
35	if (gcov_version == 0) {
36		gcov_version = gcov_info_version(info);
37		/*
38		 * Printing gcc's version magic may prove useful for debugging
39		 * incompatibility reports.
40		 */
41		pr_info("version magic: 0x%x\n", gcov_version);
42	}
43	/*
44	 * Add new profiling data structure to list and inform event
45	 * listener.
46	 */
47	gcov_info_link(info);
48	if (gcov_events_enabled)
49		gcov_event(GCOV_ADD, info);
50	mutex_unlock(&gcov_lock);
51}
52EXPORT_SYMBOL(__gcov_init);
53
54/*
55 * These functions may be referenced by gcc-generated profiling code but serve
56 * no function for kernel profiling.
57 */
58void __gcov_flush(void)
59{
60	/* Unused. */
61}
62EXPORT_SYMBOL(__gcov_flush);
63
64void __gcov_merge_add(gcov_type *counters, unsigned int n_counters)
65{
66	/* Unused. */
67}
68EXPORT_SYMBOL(__gcov_merge_add);
69
70void __gcov_merge_single(gcov_type *counters, unsigned int n_counters)
71{
72	/* Unused. */
73}
74EXPORT_SYMBOL(__gcov_merge_single);
75
76void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters)
77{
78	/* Unused. */
79}
80EXPORT_SYMBOL(__gcov_merge_delta);
81
82void __gcov_merge_ior(gcov_type *counters, unsigned int n_counters)
83{
84	/* Unused. */
85}
86EXPORT_SYMBOL(__gcov_merge_ior);
87
88void __gcov_merge_time_profile(gcov_type *counters, unsigned int n_counters)
89{
90	/* Unused. */
91}
92EXPORT_SYMBOL(__gcov_merge_time_profile);
93
94/**
95 * gcov_enable_events - enable event reporting through gcov_event()
96 *
97 * Turn on reporting of profiling data load/unload-events through the
98 * gcov_event() callback. Also replay all previous events once. This function
99 * is needed because some events are potentially generated too early for the
100 * callback implementation to handle them initially.
101 */
102void gcov_enable_events(void)
103{
104	struct gcov_info *info = NULL;
105
106	mutex_lock(&gcov_lock);
107	gcov_events_enabled = 1;
108
109	/* Perform event callback for previously registered entries. */
110	while ((info = gcov_info_next(info)))
111		gcov_event(GCOV_ADD, info);
112
113	mutex_unlock(&gcov_lock);
114}
115
116#ifdef CONFIG_MODULES
117static inline int within(void *addr, void *start, unsigned long size)
118{
119	return ((addr >= start) && (addr < start + size));
120}
121
122/* Update list and generate events when modules are unloaded. */
123static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
124				void *data)
125{
126	struct module *mod = data;
127	struct gcov_info *info = NULL;
128	struct gcov_info *prev = NULL;
129
130	if (event != MODULE_STATE_GOING)
131		return NOTIFY_OK;
132	mutex_lock(&gcov_lock);
133
134	/* Remove entries located in module from linked list. */
135	while ((info = gcov_info_next(info))) {
136		if (within(info, mod->module_core, mod->core_size)) {
137			gcov_info_unlink(prev, info);
138			if (gcov_events_enabled)
139				gcov_event(GCOV_REMOVE, info);
140		} else
141			prev = info;
142	}
143
144	mutex_unlock(&gcov_lock);
145
146	return NOTIFY_OK;
147}
148
149static struct notifier_block gcov_nb = {
150	.notifier_call	= gcov_module_notifier,
151};
152
153static int __init gcov_init(void)
154{
155	return register_module_notifier(&gcov_nb);
156}
157device_initcall(gcov_init);
158#endif /* CONFIG_MODULES */
159