1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup ScoreCPU |
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5 | * |
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6 | * @brief Epiphany exception support implementation. |
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7 | */ |
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8 | |
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9 | /* |
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10 | * Copyright (c) 2015 University of York. |
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11 | * Hesham ALMatary <hmka501@york.ac.uk> |
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12 | * |
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13 | * Redistribution and use in source and binary forms, with or without |
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14 | * modification, are permitted provided that the following conditions |
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15 | * are met: |
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16 | * 1. Redistributions of source code must retain the above copyright |
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17 | * notice, this list of conditions and the following disclaimer. |
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18 | * 2. Redistributions in binary form must reproduce the above copyright |
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19 | * notice, this list of conditions and the following disclaimer in the |
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20 | * documentation and/or other materials provided with the distribution. |
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21 | * |
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22 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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23 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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24 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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25 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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26 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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28 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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29 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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30 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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31 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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32 | * SUCH DAMAGE. |
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33 | */ |
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34 | |
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35 | #ifdef HAVE_CONFIG_H |
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36 | #include "config.h" |
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37 | #endif |
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38 | |
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39 | #include <rtems/score/cpu.h> |
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40 | |
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41 | #include <rtems/asm.h> |
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42 | #include <rtems/score/percpu.h> |
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43 | |
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44 | EXTERN(bsp_start_vector_table_begin) |
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45 | EXTERN(_Thread_Dispatch) |
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46 | PUBLIC(_ISR_Handler) |
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47 | |
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48 | .section .text, "ax" |
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49 | .align 4 |
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50 | TYPE_FUNC(_ISR_Handler) |
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51 | SYM(_ISR_Handler): |
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52 | /* Reserve space for CPU_Exception_frame */ |
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53 | sub sp, sp, #(CPU_EXCEPTION_FRAME_SIZE) |
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54 | |
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55 | str r0, [sp] |
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56 | str r1, [sp,1] |
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57 | str r2, [sp,2] |
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58 | str r3, [sp,3] |
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59 | str r4, [sp,4] |
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60 | str r5, [sp,5] |
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61 | str r6, [sp,6] |
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62 | str r7, [sp,7] |
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63 | str r8, [sp,8] |
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64 | str r9, [sp,9] |
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65 | str r10, [sp,10] |
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66 | str fp, [sp,11] |
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67 | str r12, [sp,12] |
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68 | |
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69 | /* Save interrupted task stack pointer */ |
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70 | add r1, sp, #(CPU_EXCEPTION_FRAME_SIZE + 8) |
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71 | str r1,[sp,13] |
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72 | |
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73 | str lr, [sp,14] |
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74 | str r15, [sp,15] |
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75 | str r16, [sp,16] |
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76 | str r17, [sp,17] |
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77 | str r18, [sp,18] |
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78 | str r19, [sp,19] |
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79 | str r20, [sp,20] |
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80 | str r21, [sp,21] |
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81 | str r22, [sp,22] |
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82 | str r23, [sp,23] |
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83 | str r24, [sp,24] |
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84 | str r25, [sp,25] |
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85 | str r26, [sp,26] |
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86 | str r27, [sp,27] |
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87 | str r28, [sp,28] |
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88 | str r29, [sp,29] |
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89 | str r30, [sp,30] |
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90 | str r31, [sp,31] |
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91 | str r32, [sp,32] |
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92 | str r33, [sp,33] |
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93 | str r34, [sp,34] |
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94 | str r35, [sp,35] |
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95 | str r36, [sp,36] |
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96 | str r37, [sp,37] |
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97 | str r38, [sp,38] |
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98 | str r39, [sp,39] |
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99 | str r40, [sp,40] |
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100 | str r41, [sp,41] |
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101 | str r42, [sp,42] |
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102 | str r43, [sp,43] |
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103 | str r44, [sp,44] |
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104 | str r45, [sp,45] |
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105 | str r46, [sp,46] |
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106 | str r47, [sp,47] |
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107 | str r48, [sp,48] |
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108 | str r49, [sp,49] |
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109 | str r50, [sp,50] |
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110 | str r51, [sp,51] |
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111 | str r52, [sp,52] |
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112 | str r53, [sp,53] |
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113 | str r54, [sp,54] |
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114 | str r55, [sp,55] |
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115 | str r56, [sp,56] |
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116 | str r57, [sp,57] |
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117 | str r58, [sp,58] |
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118 | str r59, [sp,59] |
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119 | str r60, [sp,60] |
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120 | str r61, [sp,61] |
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121 | /* r62 and r63 are saved from start.S interrupt entry |
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122 | * and hold vector number and _ISR_Handler address repsectively. |
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123 | */ |
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124 | |
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125 | /* Save status register */ |
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126 | movfs r1,status |
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127 | str r1, [sp,62] |
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128 | |
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129 | /* Save config register */ |
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130 | movfs r1,config |
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131 | str r1, [sp,63] |
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132 | |
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133 | /* Save interrupt return address register */ |
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134 | movfs r1,iret |
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135 | str r1, [sp,64] |
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136 | |
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137 | mov r33, %low(_Per_CPU_Information) |
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138 | movt r33, %high(_Per_CPU_Information) |
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139 | |
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140 | add r6, r33, #(PER_CPU_ISR_NEST_LEVEL) |
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141 | add r8, r33, #(PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL) |
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142 | |
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143 | /* Increment nesting level and disable thread dispatch */ |
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144 | ldr r5, [r6] |
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145 | ldr r7, [r8] |
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146 | add r5, r5, #1 |
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147 | add r7, r7, #1 |
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148 | str r5, [r6] |
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149 | str r7, [r8] |
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150 | |
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151 | /* Keep sp (Exception frame address) in r32 - Callee saved */ |
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152 | mov r32, sp |
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153 | |
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154 | /* Keep _Per_CPU_Information address in r33 - Callee saved */ |
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155 | mov r33, r18 |
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156 | |
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157 | /* Call the exception handler from vector table. |
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158 | * First function arg for C handler is vector number, |
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159 | * and the second is a pointer to exception frame. |
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160 | */ |
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161 | mov r0, r62 |
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162 | mov r1, sp |
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163 | |
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164 | mov r27, r62 |
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165 | lsl r27, r27, #2 |
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166 | mov r26, %low(bsp_start_vector_table_begin) |
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167 | movt r15, #0 |
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168 | add r27, r27, r26 |
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169 | ldr r27, [r27] |
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170 | |
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171 | /* Do not switch stacks if we are in a nested interrupt. At |
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172 | * this point r5 should be holding ISR_NEST_LEVEL value. |
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173 | */ |
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174 | sub r37, r5, #1 |
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175 | bgtu jump_to_c_handler |
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176 | |
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177 | /* Switch to RTEMS dedicated interrupt stack */ |
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178 | add sp, r18, #(PER_CPU_INTERRUPT_STACK_HIGH) |
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179 | ldr sp, [sp] |
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180 | |
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181 | jump_to_c_handler: |
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182 | jalr r27 |
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183 | |
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184 | /* Switch back to the interrupted task stack */ |
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185 | mov sp, r32 |
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186 | |
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187 | /* Get the address of _Per_CPU_Information */ |
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188 | mov r18, r33 |
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189 | |
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190 | /* Decrement nesting level and enable multitasking */ |
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191 | add r6, r18, #(PER_CPU_ISR_NEST_LEVEL) |
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192 | add r8, r18, #(PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL) |
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193 | |
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194 | ldr r5, [r6] |
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195 | ldr r7, [r8] |
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196 | sub r5, r5, #1 |
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197 | sub r7, r7, #1 |
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198 | str r5, [r6] |
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199 | str r7, [r8] |
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200 | |
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201 | /* Check if _ISR_Nest_level > 0 */ |
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202 | sub r37, r5, #0 |
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203 | bgtu exception_frame_restore |
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204 | |
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205 | /* Check if _Thread_Dispatch_disable_level > 0 */ |
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206 | sub r37, r7, #0 |
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207 | bgtu exception_frame_restore |
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208 | |
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209 | /* Check if dispatch needed */ |
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210 | add r31, r18, #(PER_CPU_DISPATCH_NEEDED) |
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211 | ldr r31, [r31] |
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212 | |
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213 | sub r35, r31, #0 |
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214 | beq exception_frame_restore |
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215 | |
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216 | mov r35, %low(_Thread_Dispatch) |
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217 | movt r35, %high(_Thread_Dispatch) |
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218 | jalr r35 |
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219 | |
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220 | exception_frame_restore: |
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221 | |
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222 | ldr r1, [sp,1] |
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223 | ldr r2, [sp,2] |
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224 | ldr r3, [sp,3] |
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225 | ldr r4, [sp,4] |
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226 | ldr r5, [sp,5] |
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227 | ldr r6, [sp,6] |
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228 | ldr r7, [sp,7] |
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229 | ldr r8, [sp,8] |
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230 | ldr r9, [sp,9] |
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231 | ldr r10, [sp,10] |
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232 | ldr fp, [sp,11] |
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233 | ldr r12, [sp,12] |
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234 | ldr lr, [sp,14] |
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235 | ldr r15, [sp,15] |
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236 | ldr r16, [sp,16] |
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237 | ldr r17, [sp,17] |
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238 | ldr r18, [sp,18] |
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239 | ldr r19, [sp,19] |
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240 | ldr r20, [sp,20] |
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241 | ldr r21, [sp,21] |
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242 | ldr r22, [sp,22] |
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243 | ldr r23, [sp,23] |
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244 | ldr r24, [sp,24] |
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245 | ldr r25, [sp,25] |
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246 | ldr r26, [sp,26] |
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247 | ldr r27, [sp,27] |
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248 | ldr r28, [sp,28] |
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249 | ldr r29, [sp,29] |
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250 | ldr r30, [sp,30] |
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251 | ldr r31, [sp,31] |
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252 | ldr r32, [sp,32] |
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253 | ldr r34, [sp,34] |
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254 | ldr r36, [sp,36] |
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255 | ldr r38, [sp,38] |
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256 | ldr r39, [sp,39] |
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257 | ldr r40, [sp,40] |
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258 | ldr r41, [sp,41] |
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259 | ldr r42, [sp,42] |
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260 | ldr r43, [sp,43] |
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261 | ldr r44, [sp,44] |
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262 | ldr r45, [sp,45] |
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263 | ldr r46, [sp,46] |
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264 | ldr r47, [sp,47] |
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265 | ldr r48, [sp,48] |
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266 | ldr r49, [sp,49] |
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267 | ldr r50, [sp,50] |
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268 | ldr r51, [sp,51] |
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269 | ldr r52, [sp,52] |
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270 | ldr r53, [sp,53] |
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271 | ldr r54, [sp,54] |
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272 | ldr r55, [sp,55] |
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273 | ldr r56, [sp,56] |
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274 | ldr r57, [sp,57] |
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275 | ldr r58, [sp,58] |
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276 | ldr r59, [sp,59] |
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277 | ldr r60, [sp,60] |
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278 | ldr r61, [sp,61] |
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279 | |
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280 | /* Restore status register */ |
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281 | ldr r0,[sp,62] |
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282 | movts status, r0 |
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283 | |
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284 | /* Restore config register */ |
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285 | ldr r0, [sp,63] |
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286 | movts config, r0 |
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287 | |
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288 | /* Restore interrupt return address register */ |
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289 | ldr r0, [sp,64] |
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290 | movts iret, r0 |
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291 | |
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292 | ldr r0,[sp] |
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293 | |
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294 | /* Restore interrupted task's stack pointer */ |
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295 | ldr sp, [sp,13] |
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296 | |
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297 | /* r62 and r63 are saved from start.S interrupt entry |
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298 | * and hold vector number and _ISR_Handler address repsectively. |
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299 | */ |
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300 | ldr r62, [sp, -8] |
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301 | ldr r63, [sp, -4] |
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302 | |
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303 | /* return from interrupt */ |
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304 | rti |
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