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 | |
25 | int gcov_events_enabled; |
26 | DEFINE_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 | */ |
36 | void 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(action: GCOV_ADD, info); |
46 | cond_resched(); |
47 | } |
48 | |
49 | mutex_unlock(lock: &gcov_lock); |
50 | } |
51 | |
52 | /** |
53 | * store_gcov_u32 - store 32 bit number in gcov format to buffer |
54 | * @buffer: target buffer or NULL |
55 | * @off: offset into the buffer |
56 | * @v: value to be stored |
57 | * |
58 | * Number format defined by gcc: numbers are recorded in the 32 bit |
59 | * unsigned binary form of the endianness of the machine generating the |
60 | * file. Returns the number of bytes stored. If @buffer is %NULL, doesn't |
61 | * store anything. |
62 | */ |
63 | size_t store_gcov_u32(void *buffer, size_t off, u32 v) |
64 | { |
65 | u32 *data; |
66 | |
67 | if (buffer) { |
68 | data = buffer + off; |
69 | *data = v; |
70 | } |
71 | |
72 | return sizeof(*data); |
73 | } |
74 | |
75 | /** |
76 | * store_gcov_u64 - store 64 bit number in gcov format to buffer |
77 | * @buffer: target buffer or NULL |
78 | * @off: offset into the buffer |
79 | * @v: value to be stored |
80 | * |
81 | * Number format defined by gcc: numbers are recorded in the 32 bit |
82 | * unsigned binary form of the endianness of the machine generating the |
83 | * file. 64 bit numbers are stored as two 32 bit numbers, the low part |
84 | * first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store |
85 | * anything. |
86 | */ |
87 | size_t store_gcov_u64(void *buffer, size_t off, u64 v) |
88 | { |
89 | u32 *data; |
90 | |
91 | if (buffer) { |
92 | data = buffer + off; |
93 | |
94 | data[0] = (v & 0xffffffffUL); |
95 | data[1] = (v >> 32); |
96 | } |
97 | |
98 | return sizeof(*data) * 2; |
99 | } |
100 | |
101 | #ifdef CONFIG_MODULES |
102 | /* Update list and generate events when modules are unloaded. */ |
103 | static int gcov_module_notifier(struct notifier_block *nb, unsigned long event, |
104 | void *data) |
105 | { |
106 | struct module *mod = data; |
107 | struct gcov_info *info = NULL; |
108 | struct gcov_info *prev = NULL; |
109 | |
110 | if (event != MODULE_STATE_GOING) |
111 | return NOTIFY_OK; |
112 | mutex_lock(&gcov_lock); |
113 | |
114 | /* Remove entries located in module from linked list. */ |
115 | while ((info = gcov_info_next(info))) { |
116 | if (gcov_info_within_module(info, mod)) { |
117 | gcov_info_unlink(prev, info); |
118 | if (gcov_events_enabled) |
119 | gcov_event(action: GCOV_REMOVE, info); |
120 | } else |
121 | prev = info; |
122 | } |
123 | |
124 | mutex_unlock(lock: &gcov_lock); |
125 | |
126 | return NOTIFY_OK; |
127 | } |
128 | |
129 | static struct notifier_block gcov_nb = { |
130 | .notifier_call = gcov_module_notifier, |
131 | }; |
132 | |
133 | static int __init gcov_init(void) |
134 | { |
135 | return register_module_notifier(nb: &gcov_nb); |
136 | } |
137 | device_initcall(gcov_init); |
138 | #endif /* CONFIG_MODULES */ |
139 | |