1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef __PERF_MUTEX_H |
3 | #define __PERF_MUTEX_H |
4 | |
5 | #include <pthread.h> |
6 | #include <stdbool.h> |
7 | |
8 | /* |
9 | * A function-like feature checking macro that is a wrapper around |
10 | * `__has_attribute`, which is defined by GCC 5+ and Clang and evaluates to a |
11 | * nonzero constant integer if the attribute is supported or 0 if not. |
12 | */ |
13 | #ifdef __has_attribute |
14 | #define HAVE_ATTRIBUTE(x) __has_attribute(x) |
15 | #else |
16 | #define HAVE_ATTRIBUTE(x) 0 |
17 | #endif |
18 | |
19 | #if HAVE_ATTRIBUTE(guarded_by) && HAVE_ATTRIBUTE(pt_guarded_by) && \ |
20 | HAVE_ATTRIBUTE(lockable) && HAVE_ATTRIBUTE(exclusive_lock_function) && \ |
21 | HAVE_ATTRIBUTE(exclusive_trylock_function) && HAVE_ATTRIBUTE(exclusive_locks_required) && \ |
22 | HAVE_ATTRIBUTE(no_thread_safety_analysis) |
23 | |
24 | /* Documents if a shared field or global variable needs to be protected by a mutex. */ |
25 | #define GUARDED_BY(x) __attribute__((guarded_by(x))) |
26 | |
27 | /* |
28 | * Documents if the memory location pointed to by a pointer should be guarded by |
29 | * a mutex when dereferencing the pointer. |
30 | */ |
31 | #define PT_GUARDED_BY(x) __attribute__((pt_guarded_by(x))) |
32 | |
33 | /* Documents if a type is a lockable type. */ |
34 | #define LOCKABLE __attribute__((lockable)) |
35 | |
36 | /* Documents functions that acquire a lock in the body of a function, and do not release it. */ |
37 | #define EXCLUSIVE_LOCK_FUNCTION(...) __attribute__((exclusive_lock_function(__VA_ARGS__))) |
38 | |
39 | /* |
40 | * Documents functions that expect a lock to be held on entry to the function, |
41 | * and release it in the body of the function. |
42 | */ |
43 | #define UNLOCK_FUNCTION(...) __attribute__((unlock_function(__VA_ARGS__))) |
44 | |
45 | /* Documents functions that try to acquire a lock, and return success or failure. */ |
46 | #define EXCLUSIVE_TRYLOCK_FUNCTION(...) \ |
47 | __attribute__((exclusive_trylock_function(__VA_ARGS__))) |
48 | |
49 | /* Documents a function that expects a mutex to be held prior to entry. */ |
50 | #define EXCLUSIVE_LOCKS_REQUIRED(...) __attribute__((exclusive_locks_required(__VA_ARGS__))) |
51 | |
52 | /* Turns off thread safety checking within the body of a particular function. */ |
53 | #define NO_THREAD_SAFETY_ANALYSIS __attribute__((no_thread_safety_analysis)) |
54 | |
55 | #else |
56 | |
57 | #define GUARDED_BY(x) |
58 | #define PT_GUARDED_BY(x) |
59 | #define LOCKABLE |
60 | #define EXCLUSIVE_LOCK_FUNCTION(...) |
61 | #define UNLOCK_FUNCTION(...) |
62 | #define EXCLUSIVE_TRYLOCK_FUNCTION(...) |
63 | #define EXCLUSIVE_LOCKS_REQUIRED(...) |
64 | #define NO_THREAD_SAFETY_ANALYSIS |
65 | |
66 | #endif |
67 | |
68 | /* |
69 | * A wrapper around the mutex implementation that allows perf to error check |
70 | * usage, etc. |
71 | */ |
72 | struct LOCKABLE mutex { |
73 | pthread_mutex_t lock; |
74 | }; |
75 | |
76 | /* A wrapper around the condition variable implementation. */ |
77 | struct cond { |
78 | pthread_cond_t cond; |
79 | }; |
80 | |
81 | /* Default initialize the mtx struct. */ |
82 | void mutex_init(struct mutex *mtx); |
83 | /* |
84 | * Initialize the mtx struct and set the process-shared rather than default |
85 | * process-private attribute. |
86 | */ |
87 | void mutex_init_pshared(struct mutex *mtx); |
88 | void mutex_destroy(struct mutex *mtx); |
89 | |
90 | void mutex_lock(struct mutex *mtx) EXCLUSIVE_LOCK_FUNCTION(*mtx); |
91 | void mutex_unlock(struct mutex *mtx) UNLOCK_FUNCTION(*mtx); |
92 | /* Tries to acquire the lock and returns true on success. */ |
93 | bool mutex_trylock(struct mutex *mtx) EXCLUSIVE_TRYLOCK_FUNCTION(true, *mtx); |
94 | |
95 | /* Default initialize the cond struct. */ |
96 | void cond_init(struct cond *cnd); |
97 | /* |
98 | * Initialize the cond struct and specify the process-shared rather than default |
99 | * process-private attribute. |
100 | */ |
101 | void cond_init_pshared(struct cond *cnd); |
102 | void cond_destroy(struct cond *cnd); |
103 | |
104 | void cond_wait(struct cond *cnd, struct mutex *mtx) EXCLUSIVE_LOCKS_REQUIRED(mtx); |
105 | void cond_signal(struct cond *cnd); |
106 | void cond_broadcast(struct cond *cnd); |
107 | |
108 | #endif /* __PERF_MUTEX_H */ |
109 | |