source: rtems/c/src/exec/score/src/coremutex.c @ 5870ac55

4.104.114.84.95
Last change on this file since 5870ac55 was 5870ac55, checked in by Joel Sherrill <joel.sherrill@…>, on Jan 5, 2000 at 10:19:21 PM

Added support for simple binary semaphores in addition to the high
power binary/mutex style semaphores already supported by RTEMS. This
was done at the request of Eric Norum <eric@…> in support
of his effort to port EPICS to RTEMS. This change consisted of
changing the nesting_allowed boolean into a lock_nesting_behavior
enumerated value as well as allowing the core mutex object to optionally
support ensuring that the holder of a binary semaphore released it.
Finally, a more subtle enhancement was to allow the non-holder to release
a priority inheritance/ceiling mutex and still allow the holding task
to return to its original priority.

  • Property mode set to 100644
File size: 2.5 KB
Line 
1/*
2 *  Mutex Handler
3 *
4 *  DESCRIPTION:
5 *
6 *  This package is the implementation of the Mutex Handler.
7 *  This handler provides synchronization and mutual exclusion capabilities.
8 *
9 *  COPYRIGHT (c) 1989-1999.
10 *  On-Line Applications Research Corporation (OAR).
11 *
12 *  The license and distribution terms for this file may be
13 *  found in the file LICENSE in this distribution or at
14 *  http://www.OARcorp.com/rtems/license.html.
15 *
16 *  $Id$
17 */
18
19#include <rtems/system.h>
20#include <rtems/score/isr.h>
21#include <rtems/score/coremutex.h>
22#include <rtems/score/states.h>
23#include <rtems/score/thread.h>
24#include <rtems/score/threadq.h>
25
26/*PAGE
27 *
28 *  _CORE_mutex_Initialize
29 *
30 *  This routine initializes a mutex at create time and set the control
31 *  structure according to the values passed.
32 *
33 *  Input parameters:
34 *    the_mutex             - the mutex control block to initialize
35 *    the_class             - the API class of the object
36 *    the_mutex_attributes  - the mutex attributes specified at create time
37 *    initial_lock          - mutex initial lock or unlocked status
38 *    proxy_extract_callout - MP specific extract callout
39 *
40 *  Output parameters:  NONE
41 */
42
43void _CORE_mutex_Initialize(
44  CORE_mutex_Control           *the_mutex,
45  Objects_Classes               the_class,
46  CORE_mutex_Attributes        *the_mutex_attributes,
47  unsigned32                    initial_lock,
48  Thread_queue_Extract_callout  proxy_extract_callout
49)
50{
51
52/* Add this to the RTEMS environment later ?????????
53  rtems_assert( initial_lock == CORE_MUTEX_LOCKED ||
54                initial_lock == CORE_MUTEX_UNLOCKED );
55 */
56
57  the_mutex->Attributes = *the_mutex_attributes;
58  the_mutex->lock       = initial_lock;
59
60#if 0
61  if ( !the_mutex_attributes->only_owner_release &&
62       the_mutex_attributes->nesting_allowed ) {
63    _Internal_error_Occurred(
64      INTERNAL_ERROR_CORE,
65      TRUE,
66      INTERNAL_ERROR_BAD_ATTRIBUTES
67    );
68  }
69#endif
70
71  if ( initial_lock == CORE_MUTEX_LOCKED ) {
72    the_mutex->nest_count = 1;
73    the_mutex->holder     = _Thread_Executing;
74    the_mutex->holder_id  = _Thread_Executing->Object.id;
75    _Thread_Executing->resource_count++;
76  } else {
77    the_mutex->nest_count = 0;
78    the_mutex->holder     = NULL;
79    the_mutex->holder_id  = 0;
80  }
81
82  _Thread_queue_Initialize(
83    &the_mutex->Wait_queue,
84    the_class,
85    _CORE_mutex_Is_fifo( the_mutex_attributes ) ?
86      THREAD_QUEUE_DISCIPLINE_FIFO : THREAD_QUEUE_DISCIPLINE_PRIORITY,
87    STATES_WAITING_FOR_MUTEX,
88    proxy_extract_callout,
89    CORE_MUTEX_TIMEOUT
90  );
91}
92
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