libmetal
condition.h
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1 /*
2  * Copyright (c) 2016, Xilinx Inc. and Contributors. All rights reserved.
3  *
4  * SPDX-License-Identifier: BSD-3-Clause
5  */
6 
7 /*
8  * @file linux/condition.h
9  * @brief Linux condition variable primitives for libmetal.
10  */
11 
12 #ifndef __METAL_CONDITION__H__
13 #error "Include metal/condition.h instead of metal/linux/condition.h"
14 #endif
15 
16 #ifndef __METAL_LINUX_CONDITION__H__
17 #define __METAL_LINUX_CONDITION__H__
18 
19 #include <unistd.h>
20 #include <sys/syscall.h>
21 #include <linux/futex.h>
22 #include <metal/atomic.h>
23 #include <stdint.h>
24 #include <limits.h>
25 #include <errno.h>
26 
27 #ifdef __cplusplus
28 extern "C" {
29 #endif
30 
31 struct metal_condition {
40 };
41 
43 #define METAL_CONDITION_INIT { ATOMIC_VAR_INIT(0), ATOMIC_VAR_INIT(0), \
44  ATOMIC_VAR_INIT(0) }
45 
46 static inline void metal_condition_init(struct metal_condition *cv)
47 {
48  atomic_init(&cv->mptr, 0);
49  atomic_init(&cv->waiters, 0);
50  atomic_init(&cv->wakeups, 0);
51 }
52 
53 static inline int metal_condition_signal(struct metal_condition *cv)
54 {
55  if (!cv)
56  return -EINVAL;
57 
58  atomic_fetch_add(&cv->wakeups, 1);
59  if (atomic_load(&cv->waiters) > 0)
60  syscall(SYS_futex, &cv->wakeups, FUTEX_WAKE, 1, NULL, NULL, 0);
61  return 0;
62 }
63 
64 static inline int metal_condition_broadcast(struct metal_condition *cv)
65 {
66  if (!cv)
67  return -EINVAL;
68 
69  atomic_fetch_add(&cv->wakeups, 1);
70  if (atomic_load(&cv->waiters) > 0)
71  syscall(SYS_futex, &cv->wakeups, FUTEX_WAKE, INT_MAX, NULL, NULL, 0);
72  return 0;
73 }
74 
75 #endif /* __METAL_LINUX_CONDITION__H__ */
atomic_uintptr_t
atomic_uint atomic_uintptr_t
Definition: atomic.h:26
atomic_fetch_add
#define atomic_fetch_add(OBJ, VAL)
Definition: atomic.h:95
metal_condition::wakeups
atomic_int wakeups
Definition: condition.h:39
metal_condition::mptr
atomic_uintptr_t mptr
Definition: condition.h:30
atomic_init
#define atomic_init(OBJ, VAL)
Definition: atomic.h:52
metal_condition_init
static void metal_condition_init(struct metal_condition *cv)
Definition: condition.h:46
metal_condition_signal
static int metal_condition_signal(struct metal_condition *cv)
Definition: condition.h:53
metal_condition
Definition: condition.h:25
metal_condition::waiters
atomic_int waiters
Definition: condition.h:38
metal_condition_broadcast
static int metal_condition_broadcast(struct metal_condition *cv)
Definition: condition.h:64
atomic_int
int atomic_int
Definition: atomic.h:24
atomic_load
#define atomic_load(OBJ)
Definition: atomic.h:60