1 | /* |
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2 | * Region Manager |
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3 | * |
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4 | * |
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5 | * COPYRIGHT (c) 1989-1999. |
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6 | * On-Line Applications Research Corporation (OAR). |
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7 | * |
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8 | * The license and distribution terms for this file may be |
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9 | * found in the file LICENSE in this distribution or at |
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10 | * http://www.rtems.com/license/LICENSE. |
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11 | * |
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12 | * $Id$ |
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13 | */ |
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14 | |
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15 | #if HAVE_CONFIG_H |
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16 | #include "config.h" |
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17 | #endif |
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18 | |
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19 | #ifdef RTEMS_REGION_SHRED_ON_FREE |
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20 | #include <string.h> |
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21 | |
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22 | #ifndef RTEMS_REGION_FREE_SHRED_PATTERN |
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23 | #define RTEMS_REGION_FREE_SHRED_PATTERN 0x00 |
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24 | #endif |
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25 | #endif |
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26 | |
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27 | #include <rtems/system.h> |
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28 | #include <rtems/rtems/status.h> |
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29 | #include <rtems/rtems/support.h> |
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30 | #include <rtems/score/object.h> |
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31 | #include <rtems/rtems/options.h> |
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32 | #include <rtems/rtems/region.h> |
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33 | #include <rtems/score/states.h> |
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34 | #include <rtems/score/thread.h> |
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35 | #include <rtems/score/apimutex.h> |
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36 | |
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37 | /*PAGE |
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38 | * |
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39 | * rtems_region_return_segment |
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40 | * |
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41 | * This directive will return a segment to its region. |
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42 | * |
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43 | * Input parameters: |
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44 | * id - region id |
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45 | * segment - pointer to segment address |
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46 | * |
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47 | * Output parameters: |
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48 | * RTEMS_SUCCESSFUL - if successful |
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49 | * error code - if unsuccessful |
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50 | */ |
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51 | |
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52 | rtems_status_code rtems_region_return_segment( |
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53 | Objects_Id id, |
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54 | void *segment |
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55 | ) |
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56 | { |
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57 | register Region_Control *the_region; |
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58 | Thread_Control *the_thread; |
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59 | Objects_Locations location; |
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60 | void **the_segment; |
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61 | #ifdef RTEMS_REGION_FREE_SHRED_PATTERN |
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62 | uint32_t size; |
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63 | #endif |
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64 | int status; |
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65 | |
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66 | _RTEMS_Lock_allocator(); |
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67 | the_region = _Region_Get( id, &location ); |
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68 | switch ( location ) { |
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69 | |
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70 | case OBJECTS_REMOTE: /* this error cannot be returned */ |
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71 | _RTEMS_Unlock_allocator(); |
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72 | return RTEMS_INTERNAL_ERROR; |
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73 | |
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74 | case OBJECTS_ERROR: |
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75 | _RTEMS_Unlock_allocator(); |
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76 | return RTEMS_INVALID_ID; |
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77 | |
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78 | case OBJECTS_LOCAL: |
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79 | |
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80 | _Region_Debug_Walk( the_region, 3 ); |
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81 | |
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82 | #ifdef RTEMS_REGION_FREE_SHRED_PATTERN |
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83 | if ( _Heap_Size_of_user_area( &the_region->Memory, segment, &size ) ) { |
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84 | memset(segment, (RTEMS_REGION_FREE_SHRED_PATTERN & 0xFF), size); |
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85 | } else { |
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86 | _RTEMS_Unlock_allocator(); |
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87 | return RTEMS_INVALID_ADDRESS; |
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88 | } |
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89 | #endif |
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90 | |
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91 | status = _Region_Free_segment( the_region, segment ); |
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92 | |
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93 | _Region_Debug_Walk( the_region, 4 ); |
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94 | |
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95 | if ( !status ) { |
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96 | _RTEMS_Unlock_allocator(); |
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97 | return RTEMS_INVALID_ADDRESS; |
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98 | } |
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99 | |
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100 | the_region->number_of_used_blocks -= 1; |
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101 | |
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102 | /* |
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103 | * Switch from using the memory allocation mutex to using a |
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104 | * dispatching disabled critical section. We have to do this |
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105 | * because this thread may unblock one or more threads that were |
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106 | * waiting on memory. |
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107 | * |
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108 | * NOTE: The following loop is O(n) where n is the number of |
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109 | * threads whose memory request is satisfied. |
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110 | */ |
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111 | _RTEMS_Unlock_allocator(); |
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112 | _Thread_Disable_dispatch(); |
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113 | |
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114 | for ( ; ; ) { |
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115 | the_thread = _Thread_queue_First( &the_region->Wait_queue ); |
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116 | |
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117 | if ( the_thread == NULL ) |
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118 | break; |
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119 | |
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120 | the_segment = (void **) _Region_Allocate_segment( |
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121 | the_region, |
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122 | the_thread->Wait.count |
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123 | ); |
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124 | |
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125 | if ( the_segment == NULL ) |
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126 | break; |
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127 | |
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128 | *(void **)the_thread->Wait.return_argument = the_segment; |
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129 | the_region->number_of_used_blocks += 1; |
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130 | _Thread_queue_Extract( &the_region->Wait_queue, the_thread ); |
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131 | the_thread->Wait.return_code = RTEMS_SUCCESSFUL; |
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132 | } |
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133 | _Thread_Enable_dispatch(); |
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134 | |
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135 | return RTEMS_SUCCESSFUL; |
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136 | } |
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137 | |
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138 | return RTEMS_INTERNAL_ERROR; /* unreached - only to remove warnings */ |
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139 | } |
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