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Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -07002/*
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>
Andrey Ryabinin9d796e662015-04-16 12:48:10 -070022#include <linux/sched.h>
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -070023#include "gcov.h"
24
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -070025static int gcov_events_enabled;
26static DEFINE_MUTEX(gcov_lock);
27
28/*
29 * __gcov_init is called by gcc-generated constructor code for each object
30 * file compiled with -fprofile-arcs.
31 */
32void __gcov_init(struct gcov_info *info)
33{
34 static unsigned int gcov_version;
35
36 mutex_lock(&gcov_lock);
37 if (gcov_version == 0) {
Frantisek Hrbata8cbce372013-11-12 15:11:24 -080038 gcov_version = gcov_info_version(info);
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -070039 /*
40 * Printing gcc's version magic may prove useful for debugging
41 * incompatibility reports.
42 */
43 pr_info("version magic: 0x%x\n", gcov_version);
44 }
45 /*
46 * Add new profiling data structure to list and inform event
47 * listener.
48 */
Frantisek Hrbata8cbce372013-11-12 15:11:24 -080049 gcov_info_link(info);
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -070050 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
Frantisek Hrbata5f41ea02013-11-12 15:11:26 -080084void __gcov_merge_ior(gcov_type *counters, unsigned int n_counters)
85{
86 /* Unused. */
87}
88EXPORT_SYMBOL(__gcov_merge_ior);
89
Yuan Pengfeia992bf82014-06-10 15:18:39 -070090void __gcov_merge_time_profile(gcov_type *counters, unsigned int n_counters)
91{
92 /* Unused. */
93}
94EXPORT_SYMBOL(__gcov_merge_time_profile);
95
Lorenzo Stoakes3e44c4712015-06-30 14:57:49 -070096void __gcov_merge_icall_topn(gcov_type *counters, unsigned int n_counters)
97{
98 /* Unused. */
99}
100EXPORT_SYMBOL(__gcov_merge_icall_topn);
101
Martin Liska05384212017-05-12 15:46:35 -0700102void __gcov_exit(void)
103{
104 /* Unused. */
105}
106EXPORT_SYMBOL(__gcov_exit);
107
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700108/**
109 * gcov_enable_events - enable event reporting through gcov_event()
110 *
111 * Turn on reporting of profiling data load/unload-events through the
112 * gcov_event() callback. Also replay all previous events once. This function
113 * is needed because some events are potentially generated too early for the
114 * callback implementation to handle them initially.
115 */
116void gcov_enable_events(void)
117{
Frantisek Hrbata8cbce372013-11-12 15:11:24 -0800118 struct gcov_info *info = NULL;
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700119
120 mutex_lock(&gcov_lock);
121 gcov_events_enabled = 1;
Frantisek Hrbata8cbce372013-11-12 15:11:24 -0800122
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700123 /* Perform event callback for previously registered entries. */
Andrey Ryabinin9d796e662015-04-16 12:48:10 -0700124 while ((info = gcov_info_next(info))) {
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700125 gcov_event(GCOV_ADD, info);
Andrey Ryabinin9d796e662015-04-16 12:48:10 -0700126 cond_resched();
127 }
Frantisek Hrbata8cbce372013-11-12 15:11:24 -0800128
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700129 mutex_unlock(&gcov_lock);
130}
131
132#ifdef CONFIG_MODULES
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700133/* Update list and generate events when modules are unloaded. */
134static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
135 void *data)
136{
137 struct module *mod = data;
Frantisek Hrbata8cbce372013-11-12 15:11:24 -0800138 struct gcov_info *info = NULL;
139 struct gcov_info *prev = NULL;
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700140
141 if (event != MODULE_STATE_GOING)
142 return NOTIFY_OK;
143 mutex_lock(&gcov_lock);
Frantisek Hrbata8cbce372013-11-12 15:11:24 -0800144
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700145 /* Remove entries located in module from linked list. */
Frantisek Hrbata8cbce372013-11-12 15:11:24 -0800146 while ((info = gcov_info_next(info))) {
Rusty Russellc65abf32015-11-26 09:43:08 +1030147 if (within_module((unsigned long)info, mod)) {
Frantisek Hrbata8cbce372013-11-12 15:11:24 -0800148 gcov_info_unlink(prev, info);
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700149 if (gcov_events_enabled)
150 gcov_event(GCOV_REMOVE, info);
151 } else
152 prev = info;
153 }
Frantisek Hrbata8cbce372013-11-12 15:11:24 -0800154
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -0700155 mutex_unlock(&gcov_lock);
156
157 return NOTIFY_OK;
158}
159
160static struct notifier_block gcov_nb = {
161 .notifier_call = gcov_module_notifier,
162};
163
164static int __init gcov_init(void)
165{
166 return register_module_notifier(&gcov_nb);
167}
168device_initcall(gcov_init);
169#endif /* CONFIG_MODULES */