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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * This code maintains a list of active profiling data structures.
4 *
5 * Copyright IBM Corp. 2009
6 * Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
7 *
8 * Uses gcc-internal data definitions.
9 * Based on the gcov-kernel patch by:
10 * Hubertus Franke <frankeh@us.ibm.com>
11 * Nigel Hinds <nhinds@us.ibm.com>
12 * Rajan Ravindran <rajancr@us.ibm.com>
13 * Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
14 * Paul Larson
15 */
16
17#define pr_fmt(fmt) "gcov: " fmt
18
19#include <linux/init.h>
20#include <linux/module.h>
21#include <linux/mutex.h>
22#include <linux/sched.h>
23#include "gcov.h"
24
25int gcov_events_enabled;
26DEFINE_MUTEX(gcov_lock);
27
28/**
29 * gcov_enable_events - enable event reporting through gcov_event()
30 *
31 * Turn on reporting of profiling data load/unload-events through the
32 * gcov_event() callback. Also replay all previous events once. This function
33 * is needed because some events are potentially generated too early for the
34 * callback implementation to handle them initially.
35 */
36void gcov_enable_events(void)
37{
38 struct gcov_info *info = NULL;
39
40 mutex_lock(&gcov_lock);
41 gcov_events_enabled = 1;
42
43 /* Perform event callback for previously registered entries. */
44 while ((info = gcov_info_next(info))) {
45 gcov_event(GCOV_ADD, info);
46 cond_resched();
47 }
48
49 mutex_unlock(&gcov_lock);
50}
51
52#ifdef CONFIG_MODULES
53/* Update list and generate events when modules are unloaded. */
54static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
55 void *data)
56{
57 struct module *mod = data;
58 struct gcov_info *info = NULL;
59 struct gcov_info *prev = NULL;
60
61 if (event != MODULE_STATE_GOING)
62 return NOTIFY_OK;
63 mutex_lock(&gcov_lock);
64
65 /* Remove entries located in module from linked list. */
66 while ((info = gcov_info_next(info))) {
67 if (gcov_info_within_module(info, mod)) {
68 gcov_info_unlink(prev, info);
69 if (gcov_events_enabled)
70 gcov_event(GCOV_REMOVE, info);
71 } else
72 prev = info;
73 }
74
75 mutex_unlock(&gcov_lock);
76
77 return NOTIFY_OK;
78}
79
80static struct notifier_block gcov_nb = {
81 .notifier_call = gcov_module_notifier,
82};
83
84static int __init gcov_init(void)
85{
86 return register_module_notifier(&gcov_nb);
87}
88device_initcall(gcov_init);
89#endif /* CONFIG_MODULES */
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 */