1 | /* mutex.h |
---|
2 | * |
---|
3 | * This include file contains all the constants and structures associated |
---|
4 | * with the Mutex Handler. A mutex is an enhanced version of the standard |
---|
5 | * Dijkstra binary semaphore used to provide synchronization and mutual |
---|
6 | * exclusion capabilities. |
---|
7 | * |
---|
8 | * COPYRIGHT (c) 1989-1999. |
---|
9 | * On-Line Applications Research Corporation (OAR). |
---|
10 | * |
---|
11 | * The license and distribution terms for this file may be |
---|
12 | * found in the file LICENSE in this distribution or at |
---|
13 | * http://www.OARcorp.com/rtems/license.html. |
---|
14 | * |
---|
15 | * $Id$ |
---|
16 | */ |
---|
17 | |
---|
18 | #ifndef __RTEMS_CORE_MUTEX_h |
---|
19 | #define __RTEMS_CORE_MUTEX_h |
---|
20 | |
---|
21 | #ifdef __cplusplus |
---|
22 | extern "C" { |
---|
23 | #endif |
---|
24 | |
---|
25 | #include <rtems/score/thread.h> |
---|
26 | #include <rtems/score/threadq.h> |
---|
27 | #include <rtems/score/priority.h> |
---|
28 | #include <rtems/score/watchdog.h> |
---|
29 | |
---|
30 | /* |
---|
31 | * The following type defines the callout which the API provides |
---|
32 | * to support global/multiprocessor operations on mutexes. |
---|
33 | */ |
---|
34 | |
---|
35 | typedef void ( *CORE_mutex_API_mp_support_callout )( |
---|
36 | Thread_Control *, |
---|
37 | Objects_Id |
---|
38 | ); |
---|
39 | |
---|
40 | /* |
---|
41 | * Blocking disciplines for a mutex. |
---|
42 | */ |
---|
43 | |
---|
44 | typedef enum { |
---|
45 | CORE_MUTEX_DISCIPLINES_FIFO, |
---|
46 | CORE_MUTEX_DISCIPLINES_PRIORITY, |
---|
47 | CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT, |
---|
48 | CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING |
---|
49 | } CORE_mutex_Disciplines; |
---|
50 | |
---|
51 | /* |
---|
52 | * Mutex handler return statuses. |
---|
53 | */ |
---|
54 | |
---|
55 | typedef enum { |
---|
56 | CORE_MUTEX_STATUS_SUCCESSFUL, |
---|
57 | CORE_MUTEX_STATUS_UNSATISFIED_NOWAIT, |
---|
58 | CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED, |
---|
59 | CORE_MUTEX_STATUS_NOT_OWNER_OF_RESOURCE, |
---|
60 | CORE_MUTEX_WAS_DELETED, |
---|
61 | CORE_MUTEX_TIMEOUT, |
---|
62 | CORE_MUTEX_STATUS_CEILING_VIOLATED |
---|
63 | } CORE_mutex_Status; |
---|
64 | |
---|
65 | /* |
---|
66 | * Mutex lock nesting behavior |
---|
67 | * |
---|
68 | * CORE_MUTEX_NESTING_ACQUIRES: |
---|
69 | * This sequence has no blocking or errors: |
---|
70 | * lock(m) |
---|
71 | * lock(m) |
---|
72 | * unlock(m) |
---|
73 | * unlock(m) |
---|
74 | * |
---|
75 | * CORE_MUTEX_NESTING_IS_ERROR |
---|
76 | * This sequence returns an error at the indicated point: |
---|
77 | * lock(m) |
---|
78 | * lock(m) - already locked error |
---|
79 | * unlock(m) |
---|
80 | * |
---|
81 | * CORE_MUTEX_NESTING_BLOCKS |
---|
82 | * This sequence performs as indicated: |
---|
83 | * lock(m) |
---|
84 | * lock(m) - deadlocks or timeouts |
---|
85 | * unlock(m) - releases |
---|
86 | */ |
---|
87 | |
---|
88 | typedef enum { |
---|
89 | CORE_MUTEX_NESTING_ACQUIRES, |
---|
90 | CORE_MUTEX_NESTING_IS_ERROR, |
---|
91 | CORE_MUTEX_NESTING_BLOCKS |
---|
92 | } CORE_mutex_Nesting_behaviors; |
---|
93 | |
---|
94 | /* |
---|
95 | * Locked and unlocked values |
---|
96 | */ |
---|
97 | |
---|
98 | #define CORE_MUTEX_UNLOCKED 1 |
---|
99 | #define CORE_MUTEX_LOCKED 0 |
---|
100 | |
---|
101 | /* |
---|
102 | * The following defines the control block used to manage the |
---|
103 | * attributes of each mutex. |
---|
104 | */ |
---|
105 | |
---|
106 | typedef struct { |
---|
107 | CORE_mutex_Nesting_behaviors lock_nesting_behavior; |
---|
108 | boolean only_owner_release; |
---|
109 | CORE_mutex_Disciplines discipline; |
---|
110 | Priority_Control priority_ceiling; |
---|
111 | } CORE_mutex_Attributes; |
---|
112 | |
---|
113 | /* |
---|
114 | * The following defines the control block used to manage each mutex. |
---|
115 | */ |
---|
116 | |
---|
117 | typedef struct { |
---|
118 | Thread_queue_Control Wait_queue; |
---|
119 | CORE_mutex_Attributes Attributes; |
---|
120 | unsigned32 lock; |
---|
121 | unsigned32 nest_count; |
---|
122 | unsigned32 blocked_count; |
---|
123 | Thread_Control *holder; |
---|
124 | Objects_Id holder_id; |
---|
125 | } CORE_mutex_Control; |
---|
126 | |
---|
127 | /* |
---|
128 | * _CORE_mutex_Initialize |
---|
129 | * |
---|
130 | * DESCRIPTION: |
---|
131 | * |
---|
132 | * This routine initializes the mutex based on the parameters passed. |
---|
133 | */ |
---|
134 | |
---|
135 | void _CORE_mutex_Initialize( |
---|
136 | CORE_mutex_Control *the_mutex, |
---|
137 | Objects_Classes the_class, |
---|
138 | CORE_mutex_Attributes *the_mutex_attributes, |
---|
139 | unsigned32 initial_lock, |
---|
140 | Thread_queue_Extract_callout proxy_extract_callout |
---|
141 | ); |
---|
142 | |
---|
143 | /* |
---|
144 | * _CORE_mutex_Seize |
---|
145 | * |
---|
146 | * DESCRIPTION: |
---|
147 | * |
---|
148 | * This routine attempts to receive a unit from the_mutex. |
---|
149 | * If a unit is available or if the wait flag is FALSE, then the routine |
---|
150 | * returns. Otherwise, the calling task is blocked until a unit becomes |
---|
151 | * available. |
---|
152 | * |
---|
153 | * NOTE: For performance reasons, this routine is implemented as |
---|
154 | * a macro that uses two support routines. |
---|
155 | */ |
---|
156 | |
---|
157 | RTEMS_INLINE_ROUTINE int _CORE_mutex_Seize_interrupt_trylock( |
---|
158 | CORE_mutex_Control *the_mutex, |
---|
159 | ISR_Level *level_p |
---|
160 | ); |
---|
161 | |
---|
162 | void _CORE_mutex_Seize_interrupt_blocking( |
---|
163 | CORE_mutex_Control *the_mutex, |
---|
164 | Watchdog_Interval timeout |
---|
165 | ); |
---|
166 | |
---|
167 | #define _CORE_mutex_Seize( \ |
---|
168 | _the_mutex, _id, _wait, _timeout, _level ) \ |
---|
169 | do { \ |
---|
170 | if ( _CORE_mutex_Seize_interrupt_trylock( _the_mutex, &_level ) ) { \ |
---|
171 | if ( !_wait ) { \ |
---|
172 | _ISR_Enable( _level ); \ |
---|
173 | _Thread_Executing->Wait.return_code = \ |
---|
174 | CORE_MUTEX_STATUS_UNSATISFIED_NOWAIT; \ |
---|
175 | } else { \ |
---|
176 | _Thread_queue_Enter_critical_section( &(_the_mutex)->Wait_queue ); \ |
---|
177 | _Thread_Executing->Wait.queue = &(_the_mutex)->Wait_queue; \ |
---|
178 | _Thread_Executing->Wait.id = _id; \ |
---|
179 | _Thread_Disable_dispatch(); \ |
---|
180 | _ISR_Enable( _level ); \ |
---|
181 | _CORE_mutex_Seize_interrupt_blocking( _the_mutex, _timeout ); \ |
---|
182 | } \ |
---|
183 | } \ |
---|
184 | } while (0) |
---|
185 | |
---|
186 | /* |
---|
187 | * _CORE_mutex_Surrender |
---|
188 | * |
---|
189 | * DESCRIPTION: |
---|
190 | * |
---|
191 | * This routine frees a unit to the mutex. If a task was blocked waiting for |
---|
192 | * a unit from this mutex, then that task will be readied and the unit |
---|
193 | * given to that task. Otherwise, the unit will be returned to the mutex. |
---|
194 | */ |
---|
195 | |
---|
196 | CORE_mutex_Status _CORE_mutex_Surrender( |
---|
197 | CORE_mutex_Control *the_mutex, |
---|
198 | Objects_Id id, |
---|
199 | CORE_mutex_API_mp_support_callout api_mutex_mp_support |
---|
200 | ); |
---|
201 | |
---|
202 | /* |
---|
203 | * _CORE_mutex_Flush |
---|
204 | * |
---|
205 | * DESCRIPTION: |
---|
206 | * |
---|
207 | * This routine assists in the deletion of a mutex by flushing the associated |
---|
208 | * wait queue. |
---|
209 | */ |
---|
210 | |
---|
211 | void _CORE_mutex_Flush( |
---|
212 | CORE_mutex_Control *the_mutex, |
---|
213 | Thread_queue_Flush_callout remote_extract_callout, |
---|
214 | unsigned32 status |
---|
215 | ); |
---|
216 | |
---|
217 | #ifndef __RTEMS_APPLICATION__ |
---|
218 | #include <rtems/score/coremutex.inl> |
---|
219 | #endif |
---|
220 | |
---|
221 | #ifdef __cplusplus |
---|
222 | } |
---|
223 | #endif |
---|
224 | |
---|
225 | #endif |
---|
226 | /* end of include file */ |
---|
227 | |
---|