1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Thread Dispatch Disable Functions |
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5 | * |
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6 | * @ingroup ScoreThread |
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7 | */ |
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8 | |
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9 | /* |
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10 | * COPYRIGHT (c) 1989-2011. |
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11 | * On-Line Applications Research Corporation (OAR). |
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12 | * |
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13 | * The license and distribution terms for this file may be |
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14 | * found in the file LICENSE in this distribution or at |
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15 | * http://www.rtems.com/license/LICENSE. |
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16 | */ |
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17 | |
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18 | #include <rtems/system.h> |
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19 | #include <rtems/score/apiext.h> |
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20 | #include <rtems/score/context.h> |
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21 | #include <rtems/score/interr.h> |
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22 | #include <rtems/score/isr.h> |
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23 | #include <rtems/score/object.h> |
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24 | #include <rtems/score/priority.h> |
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25 | #include <rtems/score/states.h> |
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26 | #include <rtems/score/sysstate.h> |
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27 | #include <rtems/score/threaddispatch.h> |
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28 | |
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29 | #define NO_OWNER_CPU 0xffffffffU |
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30 | |
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31 | void _Thread_Dispatch_initialization( void ) |
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32 | { |
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33 | Thread_Dispatch_disable_level_lock_control *level_lock = |
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34 | &_Thread_Dispatch_disable_level_lock; |
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35 | |
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36 | _Thread_Dispatch_disable_level = 0; |
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37 | _SMP_lock_Initialize( &level_lock->lock ); |
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38 | level_lock->owner_cpu = NO_OWNER_CPU; |
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39 | _Thread_Dispatch_set_disable_level( 1 ); |
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40 | } |
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41 | |
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42 | uint32_t _Thread_Dispatch_get_disable_level(void) |
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43 | { |
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44 | return _Thread_Dispatch_disable_level; |
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45 | } |
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46 | |
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47 | uint32_t _Thread_Dispatch_increment_disable_level( void ) |
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48 | { |
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49 | Thread_Dispatch_disable_level_lock_control *level_lock = |
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50 | &_Thread_Dispatch_disable_level_lock; |
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51 | ISR_Level isr_level; |
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52 | uint32_t self_cpu; |
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53 | uint32_t disable_level; |
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54 | |
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55 | _ISR_Disable_on_this_core( isr_level ); |
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56 | |
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57 | /* |
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58 | * We must obtain the processor ID after interrupts are disabled since a |
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59 | * non-optimizing compiler may store the value on the stack and read it back. |
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60 | */ |
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61 | self_cpu = _SMP_Get_current_processor(); |
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62 | |
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63 | if ( level_lock->owner_cpu != self_cpu ) { |
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64 | _SMP_lock_Acquire( &level_lock->lock ); |
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65 | level_lock->owner_cpu = self_cpu; |
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66 | level_lock->nest_level = 1; |
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67 | } else { |
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68 | ++level_lock->nest_level; |
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69 | } |
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70 | |
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71 | disable_level = _Thread_Dispatch_disable_level; |
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72 | ++disable_level; |
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73 | _Thread_Dispatch_disable_level = disable_level; |
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74 | |
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75 | _ISR_Enable_on_this_core( isr_level ); |
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76 | |
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77 | return disable_level; |
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78 | } |
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79 | |
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80 | uint32_t _Thread_Dispatch_decrement_disable_level( void ) |
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81 | { |
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82 | Thread_Dispatch_disable_level_lock_control *level_lock = |
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83 | &_Thread_Dispatch_disable_level_lock; |
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84 | ISR_Level isr_level; |
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85 | uint32_t disable_level; |
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86 | |
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87 | _ISR_Disable_on_this_core( isr_level ); |
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88 | |
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89 | disable_level = _Thread_Dispatch_disable_level; |
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90 | --disable_level; |
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91 | _Thread_Dispatch_disable_level = disable_level; |
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92 | |
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93 | --level_lock->nest_level; |
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94 | if ( level_lock->nest_level == 0 ) { |
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95 | level_lock->owner_cpu = NO_OWNER_CPU; |
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96 | _SMP_lock_Release( &level_lock->lock ); |
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97 | } |
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98 | |
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99 | _ISR_Enable_on_this_core( isr_level ); |
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100 | |
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101 | return disable_level; |
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102 | } |
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103 | |
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104 | |
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105 | /* |
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106 | * Note this method is taking a heavy handed approach to |
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107 | * setting the dispatch level. This may be optimized at a |
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108 | * later timee, but it must be in such a way that the nesting |
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109 | * level is decremented by the same number as the dispatch level. |
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110 | * This approach is safest until we are sure the nested spinlock |
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111 | * is successfully working with smp isr source code. |
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112 | */ |
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113 | |
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114 | uint32_t _Thread_Dispatch_set_disable_level(uint32_t value) |
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115 | { |
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116 | /* |
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117 | * If we need the dispatch level to go higher |
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118 | * call increment method the desired number of times. |
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119 | */ |
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120 | |
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121 | while ( value > _Thread_Dispatch_disable_level ) { |
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122 | _Thread_Dispatch_increment_disable_level(); |
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123 | } |
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124 | |
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125 | /* |
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126 | * If we need the dispatch level to go lower |
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127 | * call increment method the desired number of times. |
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128 | */ |
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129 | |
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130 | while ( value < _Thread_Dispatch_disable_level ) { |
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131 | _Thread_Dispatch_decrement_disable_level(); |
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132 | } |
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133 | |
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134 | return value; |
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135 | } |
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