1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup ScoreTLS |
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5 | * |
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6 | * @brief Thread-Local Storage (TLS) |
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7 | */ |
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8 | |
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9 | /* |
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10 | * Copyright (c) 2014 embedded brains GmbH. All rights reserved. |
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11 | * |
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12 | * embedded brains GmbH |
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13 | * Dornierstr. 4 |
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14 | * 82178 Puchheim |
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15 | * Germany |
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16 | * <rtems@embedded-brains.de> |
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17 | * |
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18 | * The license and distribution terms for this file may be |
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19 | * found in the file LICENSE in this distribution or at |
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20 | * http://www.rtems.org/license/LICENSE. |
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21 | */ |
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22 | |
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23 | #ifndef _RTEMS_SCORE_TLS_H |
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24 | #define _RTEMS_SCORE_TLS_H |
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25 | |
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26 | #include <rtems/score/cpu.h> |
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27 | |
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28 | #include <string.h> |
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29 | |
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30 | #ifdef __cplusplus |
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31 | extern "C" { |
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32 | #endif /* __cplusplus */ |
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33 | |
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34 | /** |
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35 | * @defgroup ScoreTLS Thread-Local Storage (TLS) |
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36 | * |
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37 | * @ingroup Score |
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38 | * |
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39 | * @brief Thread-local storage (TLS) support. |
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40 | * |
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41 | * Variants I and II are according to Ulrich Drepper, "ELF Handling For |
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42 | * Thread-Local Storage". |
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43 | * |
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44 | * @{ |
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45 | */ |
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46 | |
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47 | extern char _TLS_Data_begin[]; |
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48 | |
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49 | extern char _TLS_Data_end[]; |
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50 | |
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51 | extern char _TLS_Data_size[]; |
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52 | |
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53 | extern char _TLS_BSS_begin[]; |
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54 | |
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55 | extern char _TLS_BSS_end[]; |
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56 | |
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57 | extern char _TLS_BSS_size[]; |
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58 | |
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59 | extern char _TLS_Size[]; |
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60 | |
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61 | extern char _TLS_Alignment[]; |
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62 | |
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63 | typedef struct { |
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64 | /* |
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65 | * FIXME: Not sure if the generation number type is correct for all |
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66 | * architectures. |
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67 | */ |
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68 | uint32_t generation_number; |
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69 | |
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70 | void *tls_blocks[1]; |
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71 | } TLS_Dynamic_thread_vector; |
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72 | |
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73 | typedef struct { |
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74 | TLS_Dynamic_thread_vector *dtv; |
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75 | uintptr_t reserved; |
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76 | } TLS_Thread_control_block; |
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77 | |
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78 | typedef struct { |
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79 | uintptr_t module; |
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80 | uintptr_t offset; |
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81 | } TLS_Index; |
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82 | |
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83 | static inline uintptr_t _TLS_Heap_align_up( uintptr_t val ) |
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84 | { |
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85 | uintptr_t msk = CPU_HEAP_ALIGNMENT - 1; |
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86 | |
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87 | return (val + msk) & ~msk; |
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88 | } |
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89 | |
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90 | static inline uintptr_t _TLS_Get_thread_control_block_area_size( |
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91 | uintptr_t alignment |
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92 | ) |
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93 | { |
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94 | return alignment <= sizeof(TLS_Thread_control_block) ? |
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95 | sizeof(TLS_Thread_control_block) : alignment; |
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96 | } |
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97 | |
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98 | static inline uintptr_t _TLS_Get_allocation_size( |
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99 | uintptr_t size, |
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100 | uintptr_t alignment |
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101 | ) |
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102 | { |
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103 | uintptr_t aligned_size = _TLS_Heap_align_up( size ); |
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104 | |
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105 | return _TLS_Get_thread_control_block_area_size( alignment ) |
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106 | + aligned_size + sizeof(TLS_Dynamic_thread_vector); |
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107 | } |
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108 | |
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109 | static inline void *_TLS_Copy_and_clear( void *tls_area ) |
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110 | { |
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111 | tls_area = memcpy( tls_area, _TLS_Data_begin, (size_t) _TLS_Data_size ); |
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112 | |
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113 | memset( |
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114 | (char *) tls_area + (size_t) _TLS_BSS_begin - (size_t) _TLS_Data_begin, |
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115 | 0, |
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116 | (size_t) _TLS_BSS_size |
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117 | ); |
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118 | |
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119 | return tls_area; |
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120 | } |
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121 | |
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122 | static inline void *_TLS_Initialize( |
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123 | void *tls_block, |
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124 | TLS_Thread_control_block *tcb, |
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125 | TLS_Dynamic_thread_vector *dtv |
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126 | ) |
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127 | { |
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128 | tcb->dtv = dtv; |
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129 | dtv->generation_number = 1; |
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130 | dtv->tls_blocks[0] = tls_block; |
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131 | |
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132 | return _TLS_Copy_and_clear( tls_block ); |
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133 | } |
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134 | |
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135 | /* Use Variant I, TLS offsets emitted by linker takes the TCB into account */ |
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136 | static inline void *_TLS_TCB_at_area_begin_initialize( void *tls_area ) |
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137 | { |
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138 | void *tls_block = (char *) tls_area |
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139 | + _TLS_Get_thread_control_block_area_size( (uintptr_t) _TLS_Alignment ); |
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140 | TLS_Thread_control_block *tcb = tls_area; |
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141 | uintptr_t aligned_size = _TLS_Heap_align_up( (uintptr_t) _TLS_Size ); |
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142 | TLS_Dynamic_thread_vector *dtv = (TLS_Dynamic_thread_vector *) |
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143 | ((char *) tls_block + aligned_size); |
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144 | |
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145 | return _TLS_Initialize( tls_block, tcb, dtv ); |
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146 | } |
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147 | |
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148 | /* Use Variant I, TLS offsets emitted by linker neglects the TCB */ |
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149 | static inline void *_TLS_TCB_before_TLS_block_initialize( void *tls_area ) |
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150 | { |
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151 | void *tls_block = (char *) tls_area |
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152 | + _TLS_Get_thread_control_block_area_size( (uintptr_t) _TLS_Alignment ); |
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153 | TLS_Thread_control_block *tcb = (TLS_Thread_control_block *) |
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154 | ((char *) tls_block - sizeof(*tcb)); |
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155 | uintptr_t aligned_size = _TLS_Heap_align_up( (uintptr_t) _TLS_Size ); |
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156 | TLS_Dynamic_thread_vector *dtv = (TLS_Dynamic_thread_vector *) |
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157 | ((char *) tls_block + aligned_size); |
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158 | |
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159 | return _TLS_Initialize( tls_block, tcb, dtv ); |
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160 | } |
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161 | |
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162 | /* Use Variant II */ |
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163 | static inline void *_TLS_TCB_after_TLS_block_initialize( void *tls_area ) |
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164 | { |
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165 | uintptr_t size = (uintptr_t) _TLS_Size; |
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166 | uintptr_t tls_align = (uintptr_t) _TLS_Alignment; |
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167 | uintptr_t tls_mask = tls_align - 1; |
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168 | uintptr_t heap_align = _TLS_Heap_align_up( tls_align ); |
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169 | uintptr_t heap_mask = heap_align - 1; |
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170 | TLS_Thread_control_block *tcb = (TLS_Thread_control_block *) |
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171 | ((char *) tls_area + ((size + heap_mask) & ~heap_mask)); |
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172 | void *tls_block = (char *) tcb - ((size + tls_mask) & ~tls_mask); |
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173 | TLS_Dynamic_thread_vector *dtv = (TLS_Dynamic_thread_vector *) |
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174 | ((char *) tcb + sizeof(*tcb)); |
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175 | |
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176 | _TLS_Initialize( tls_block, tcb, dtv ); |
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177 | |
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178 | return tcb; |
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179 | } |
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180 | |
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181 | /** @} */ |
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182 | |
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183 | #ifdef __cplusplus |
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184 | } |
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185 | #endif /* __cplusplus */ |
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186 | |
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187 | #endif /* _RTEMS_SCORE_TLS_H */ |
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