1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Allocate and Initialize Per CPU Structures |
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5 | * @ingroup PerCPU |
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6 | */ |
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7 | |
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8 | /* |
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9 | * COPYRIGHT (c) 1989-2011. |
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10 | * On-Line Applications Research Corporation (OAR). |
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11 | * |
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12 | * The license and distribution terms for this file may be |
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13 | * found in the file LICENSE in this distribution or at |
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14 | * http://www.rtems.org/license/LICENSE. |
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15 | */ |
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16 | |
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17 | #if HAVE_CONFIG_H |
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18 | #include "config.h" |
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19 | #endif |
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20 | |
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21 | #include <rtems/score/percpu.h> |
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22 | #include <rtems/score/assert.h> |
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23 | #include <rtems/score/smpimpl.h> |
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24 | #include <rtems/config.h> |
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25 | #include <rtems/fatal.h> |
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26 | |
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27 | #if defined(RTEMS_SMP) |
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28 | |
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29 | static SMP_lock_Control _Per_CPU_State_lock = |
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30 | SMP_LOCK_INITIALIZER("per-CPU state"); |
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31 | |
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32 | static void _Per_CPU_State_busy_wait( |
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33 | const Per_CPU_Control *per_cpu, |
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34 | Per_CPU_State new_state |
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35 | ) |
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36 | { |
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37 | Per_CPU_State state = per_cpu->state; |
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38 | |
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39 | switch ( new_state ) { |
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40 | case PER_CPU_STATE_REQUEST_START_MULTITASKING: |
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41 | while ( |
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42 | state != PER_CPU_STATE_READY_TO_START_MULTITASKING |
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43 | && state != PER_CPU_STATE_SHUTDOWN |
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44 | ) { |
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45 | _CPU_SMP_Processor_event_receive(); |
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46 | state = per_cpu->state; |
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47 | } |
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48 | break; |
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49 | case PER_CPU_STATE_UP: |
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50 | while ( |
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51 | state != PER_CPU_STATE_REQUEST_START_MULTITASKING |
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52 | && state != PER_CPU_STATE_SHUTDOWN |
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53 | ) { |
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54 | _CPU_SMP_Processor_event_receive(); |
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55 | state = per_cpu->state; |
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56 | } |
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57 | break; |
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58 | default: |
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59 | /* No need to wait */ |
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60 | break; |
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61 | } |
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62 | } |
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63 | |
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64 | static Per_CPU_State _Per_CPU_State_get_next( |
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65 | Per_CPU_State current_state, |
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66 | Per_CPU_State new_state |
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67 | ) |
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68 | { |
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69 | switch ( current_state ) { |
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70 | case PER_CPU_STATE_INITIAL: |
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71 | switch ( new_state ) { |
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72 | case PER_CPU_STATE_READY_TO_START_MULTITASKING: |
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73 | case PER_CPU_STATE_SHUTDOWN: |
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74 | /* Change is acceptable */ |
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75 | break; |
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76 | default: |
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77 | new_state = PER_CPU_STATE_SHUTDOWN; |
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78 | break; |
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79 | } |
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80 | break; |
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81 | case PER_CPU_STATE_READY_TO_START_MULTITASKING: |
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82 | switch ( new_state ) { |
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83 | case PER_CPU_STATE_REQUEST_START_MULTITASKING: |
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84 | case PER_CPU_STATE_SHUTDOWN: |
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85 | /* Change is acceptable */ |
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86 | break; |
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87 | default: |
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88 | new_state = PER_CPU_STATE_SHUTDOWN; |
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89 | break; |
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90 | } |
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91 | break; |
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92 | case PER_CPU_STATE_REQUEST_START_MULTITASKING: |
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93 | switch ( new_state ) { |
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94 | case PER_CPU_STATE_UP: |
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95 | case PER_CPU_STATE_SHUTDOWN: |
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96 | /* Change is acceptable */ |
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97 | break; |
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98 | default: |
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99 | new_state = PER_CPU_STATE_SHUTDOWN; |
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100 | break; |
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101 | } |
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102 | break; |
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103 | default: |
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104 | new_state = PER_CPU_STATE_SHUTDOWN; |
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105 | break; |
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106 | } |
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107 | |
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108 | return new_state; |
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109 | } |
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110 | |
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111 | void _Per_CPU_State_change( |
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112 | Per_CPU_Control *per_cpu, |
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113 | Per_CPU_State new_state |
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114 | ) |
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115 | { |
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116 | SMP_lock_Control *lock = &_Per_CPU_State_lock; |
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117 | SMP_lock_Context lock_context; |
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118 | Per_CPU_State next_state; |
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119 | |
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120 | _Per_CPU_State_busy_wait( per_cpu, new_state ); |
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121 | |
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122 | _SMP_lock_ISR_disable_and_acquire( lock, &lock_context ); |
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123 | |
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124 | next_state = _Per_CPU_State_get_next( per_cpu->state, new_state ); |
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125 | per_cpu->state = next_state; |
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126 | |
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127 | if ( next_state == PER_CPU_STATE_SHUTDOWN ) { |
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128 | uint32_t ncpus = rtems_configuration_get_maximum_processors(); |
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129 | uint32_t cpu; |
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130 | |
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131 | for ( cpu = 0 ; cpu < ncpus ; ++cpu ) { |
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132 | Per_CPU_Control *other_cpu = _Per_CPU_Get_by_index( cpu ); |
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133 | |
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134 | if ( per_cpu != other_cpu ) { |
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135 | switch ( other_cpu->state ) { |
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136 | case PER_CPU_STATE_UP: |
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137 | _SMP_Send_message( cpu, SMP_MESSAGE_SHUTDOWN ); |
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138 | break; |
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139 | default: |
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140 | /* Nothing to do */ |
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141 | break; |
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142 | } |
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143 | |
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144 | other_cpu->state = PER_CPU_STATE_SHUTDOWN; |
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145 | } |
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146 | } |
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147 | } |
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148 | |
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149 | _CPU_SMP_Processor_event_broadcast(); |
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150 | |
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151 | _SMP_lock_Release_and_ISR_enable( lock, &lock_context ); |
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152 | |
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153 | if ( |
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154 | next_state == PER_CPU_STATE_SHUTDOWN |
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155 | && new_state != PER_CPU_STATE_SHUTDOWN |
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156 | ) { |
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157 | rtems_fatal( RTEMS_FATAL_SOURCE_SMP, SMP_FATAL_SHUTDOWN ); |
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158 | } |
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159 | } |
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160 | |
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161 | #else |
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162 | /* |
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163 | * On single core systems, we can efficiently directly access a single |
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164 | * statically allocated per cpu structure. And the fields are initialized |
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165 | * as individual elements just like it has always been done. |
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166 | */ |
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167 | Per_CPU_Control_envelope _Per_CPU_Information[1]; |
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168 | #endif |
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