1 | /******************************************************************************** |
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2 | * File : giet.S |
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3 | * Author : Alain Greiner |
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4 | * Date : 15/01/2014 |
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5 | ********************************************************************************* |
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6 | * This is a very simple Interrupts/Exception/Traps handler for a generic |
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7 | * multi-clusters / multi-processors TSAR architecture (up to 256 clusters, |
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8 | * up to 4 processors per cluster). |
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9 | * The physical address is 40 bits, and the 8 MSB bits A[39:32] define the |
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10 | * cluster index. |
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11 | ********************************************************************************/ |
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12 | |
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13 | #include "hard_config.h" |
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14 | |
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15 | .section .giet,"ax",@progbits |
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16 | .align 2 |
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17 | .global _interrupt_vector |
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18 | |
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19 | .extern seg_xcu_base |
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20 | .extern seg_tty_base |
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21 | |
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22 | .extern _procid |
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23 | .extern _proctime |
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24 | .extern _tty_write |
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25 | .extern _tty_read |
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26 | .extern _tty_read_irq |
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27 | .extern _locks_read |
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28 | .extern _locks_write |
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29 | .extern _exit |
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30 | .extern _fb_sync_write |
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31 | .extern _fb_sync_read |
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32 | .extern _ioc_write |
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33 | .extern _ioc_read |
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34 | .extern _ioc_completed |
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35 | .extern _itoa_hex |
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36 | .extern _barrier_init |
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37 | .extern _barrier_wait |
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38 | |
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39 | .ent _giet |
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40 | |
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41 | /**************************************************************** |
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42 | * Cause Table (indexed by the Cause register) |
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43 | ****************************************************************/ |
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44 | tab_causes: |
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45 | .word _int_handler /* 0000 : external interrupt */ |
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46 | .word _cause_ukn /* 0001 : undefined exception */ |
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47 | .word _cause_ukn /* 0010 : undefined exception */ |
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48 | .word _cause_ukn /* 0011 : undefined exception */ |
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49 | .word _cause_adel /* 0100 : illegal address read exception */ |
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50 | .word _cause_ades /* 0101 : illegal address write exception */ |
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51 | .word _cause_ibe /* 0110 : instruction bus error exception */ |
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52 | .word _cause_dbe /* 0111 : data bus error exception */ |
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53 | .word _sys_handler /* 1000 : system call */ |
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54 | .word _cause_bp /* 1001 : breakpoint exception */ |
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55 | .word _cause_ri /* 1010 : illegal codop exception */ |
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56 | .word _cause_cpu /* 1011 : illegal coprocessor access */ |
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57 | .word _cause_ovf /* 1100 : arithmetic overflow exception */ |
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58 | .word _cause_ukn /* 1101 : undefined exception */ |
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59 | .word _cause_ukn /* 1110 : undefined exception */ |
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60 | .word _cause_ukn /* 1111 : undefined exception */ |
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61 | |
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62 | .space 320 |
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63 | |
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64 | /**************************************************************** |
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65 | * Entry point (base + 0x180) |
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66 | ****************************************************************/ |
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67 | _giet: |
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68 | mfc0 $27, $13 /* Cause Register analysis */ |
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69 | la $26, seg_kcode_base /* $26 <= tab_causes */ |
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70 | andi $27, $27, 0x3c |
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71 | addu $26, $26, $27 /* $26 <= &tab_causes[XCODE] */ |
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72 | lw $26, ($26) |
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73 | jr $26 /* Jump to tab_causes[XCODE] */ |
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74 | |
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75 | .end _giet |
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76 | |
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77 | /**************************************************************** |
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78 | * System Call Handler |
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79 | * |
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80 | * As the GIET_TSAR does not support system calls, |
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81 | * an error message is displayed on TTY0, the program is killed. |
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82 | ****************************************************************/ |
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83 | .ent _sys_handler |
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84 | |
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85 | _sys_handler: |
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86 | la $4, _msg_uknsyscall /* $4 <= message address */ |
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87 | li $5, 36 /* $5 <= message length */ |
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88 | li $6, 0 /* $6 <= TTY0 */ |
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89 | jal _tty_write /* print unknown message */ |
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90 | nop |
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91 | |
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92 | la $4, _msg_epc /* $4 <= message address */ |
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93 | li $5, 8 /* $5 <= message length */ |
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94 | li $6, 0 /* $6 <= TTY0 */ |
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95 | jal _tty_write /* print EPC message */ |
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96 | nop |
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97 | |
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98 | mfc0 $4, $14 /* $4 <= EPC */ |
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99 | la $5, _itoa_buffer /* $5 <= buffer address */ |
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100 | addiu $5, $5, 2 /* skip the 0x prefix */ |
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101 | jal _itoa_hex /* fill the buffer */ |
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102 | nop |
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103 | |
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104 | la $4, _itoa_buffer /* $4 <= buffer address */ |
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105 | li $5, 10 /* $5 <= buffer length */ |
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106 | li $6, 0 /* $6 <= TTY0 */ |
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107 | jal _tty_write /* print EPC value */ |
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108 | nop |
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109 | |
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110 | j _exit /* end of program */ |
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111 | |
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112 | _itoa_buffer: .ascii "0x00000000" |
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113 | |
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114 | .align 2 |
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115 | |
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116 | .end _sys_handler |
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117 | |
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118 | /**************************************************************** |
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119 | * Interrupt Handler |
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120 | * This simple interrupt handler cannot be interrupted. |
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121 | * It uses the SoCLib VCI_XICU component. |
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122 | * It makes the assumption that there is only one interrupt per |
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123 | * entry in the interrupt vector (it can be PTI, HWI, or WTI). |
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124 | * In case of a multi-clusters architecture, it exist one XCU |
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125 | * per cluster, and the base address of the ICU segment depends |
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126 | * on both the cluster_xy and the proc_id: |
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127 | * - base_address = seg_xcu_base + (32*local_id) + (4G*cluster_xy) |
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128 | * - cluster_xy = proc_id / NB_PROCS_MAX |
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129 | * - local_id = proc_id % NB_PROCS_MAX |
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130 | * If no active interrupt is found in the PRIO register, |
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131 | * nothing is done. |
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132 | * The interrupt vector (32 ISR addresses array stored at |
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133 | * _interrupt_vector address) is initialised with the default |
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134 | * ISR address. The actual ISR addresses are supposed to be written |
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135 | * in the interrupt vector array by the boot code. |
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136 | * All non persistant registers, such as $1 to $15, and $24 to $25, |
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137 | * as well as register $31 and EPC, are saved in the interrupted |
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138 | * program stack, before calling the Interrupt Service Routine. |
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139 | * These registers can be used by the ISR code. |
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140 | ***************************************************************/ |
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141 | .ent _int_handler |
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142 | |
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143 | _int_handler: |
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144 | addiu $29, $29, -23*4 /* stack space reservation */ |
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145 | .set noat |
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146 | sw $1, 4*4($29) /* save $1 */ |
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147 | .set at |
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148 | sw $2, 4*5($29) /* save $2 */ |
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149 | sw $3, 4*6($29) /* save $3 */ |
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150 | sw $4, 4*7($29) /* save $4 */ |
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151 | sw $5, 4*8($29) /* save $5 */ |
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152 | sw $6, 4*9($29) /* save $6 */ |
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153 | sw $7, 4*10($29) /* save $7 */ |
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154 | sw $8, 4*11($29) /* save $8 */ |
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155 | sw $9, 4*12($29) /* save $9 */ |
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156 | sw $10, 4*13($29) /* save $10 */ |
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157 | sw $11, 4*14($29) /* save $11 */ |
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158 | sw $12, 4*15($29) /* save $12 */ |
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159 | sw $13, 4*16($29) /* save $13 */ |
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160 | sw $14, 4*17($29) /* save $14 */ |
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161 | sw $15, 4*18($29) /* save $15 */ |
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162 | sw $24, 4*19($29) /* save $24 */ |
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163 | sw $25, 4*20($29) /* save $25 */ |
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164 | sw $31, 4*21($29) /* save $31 */ |
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165 | mfc0 $27, $14 |
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166 | sw $27, 4*22($29) /* save EPC */ |
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167 | |
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168 | /* XICU PRIO register address computation */ |
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169 | /* It depends on both the cluster_xy & local_id, */ |
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170 | /* and we must use the physical address extension */ |
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171 | mfc0 $10, $15, 1 /* $10 <= proc_id */ |
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172 | andi $10, $10, 0x3FF /* at most 1024 processors */ |
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173 | li $11, NB_PROCS_MAX |
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174 | divu $10, $11 |
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175 | mflo $12 /* $12 <= cluster_xy */ |
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176 | mfhi $13 /* $13 <= local_id */ |
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177 | la $14, seg_xcu_base /* $14 <= seg_xcu_base */ |
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178 | |
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179 | li $7, 0b011110000000 /* $7 <= PRIO offset */ |
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180 | sll $8, $13, 2 /* $8 <= local_id*4 */ |
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181 | addu $9, $7, $8 /* $9 <= PRIO offset + local_id*4 */ |
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182 | addu $26, $9, $14 /* $26 <= seg_icu_base + PRIO offset + local_id*4 */ |
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183 | |
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184 | /* XCU[cluster_xy] access to get PRIO register value */ |
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185 | mtc2 $12, $24 /* set PADDR extension */ |
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186 | lw $15, 0($26) /* $15 <= PRIO register value */ |
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187 | mtc2 $0, $24 /* reset PADDR extension */ |
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188 | |
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189 | /* test PTI, then HWI, then WTI */ |
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190 | andi $27, $15, 0x1 /* test bit T in PRIO register */ |
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191 | bne $27, $0, _int_PTI /* branch to PTI handler */ |
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192 | andi $27, $15, 0x2 /* test bit W in PRIO register */ |
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193 | bne $27, $0, _int_HWI /* branch to HWI handler */ |
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194 | andi $27, $15, 0x4 /* test bit W in PRIO register */ |
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195 | bne $27, $0, _int_WTI /* branch to WTI handler */ |
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196 | |
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197 | /* exit interrupt handler: restore registers */ |
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198 | _int_restore: |
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199 | .set noat |
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200 | lw $1, 4*4($29) |
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201 | .set at |
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202 | lw $2, 4*5($29) |
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203 | lw $3, 4*6($29) |
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204 | lw $4, 4*7($29) |
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205 | lw $5, 4*8($29) |
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206 | lw $6, 4*9($29) |
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207 | lw $7, 4*10($29) |
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208 | lw $8, 4*11($29) |
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209 | lw $9, 4*12($29) |
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210 | lw $10, 4*13($29) |
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211 | lw $11, 4*14($29) |
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212 | lw $12, 4*15($29) |
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213 | lw $13, 4*16($29) |
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214 | lw $14, 4*17($29) |
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215 | lw $15, 4*18($29) |
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216 | lw $24, 4*19($29) |
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217 | lw $25, 4*20($29) |
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218 | lw $31, 4*21($29) |
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219 | lw $27, 4*22($29) /* get EPC */ |
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220 | addiu $29, $29, 23*4 /* restore SP */ |
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221 | mtc0 $27, $14 /* restore EPC */ |
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222 | eret /* exit GIET */ |
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223 | |
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224 | /* The PTI handler get PTI index, */ |
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225 | /* acknowledge the PTI register */ |
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226 | /* and call the corresponding ISR */ |
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227 | _int_PTI: |
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228 | srl $26, $15, 6 /* $26 <= PRIO >> 6 */ |
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229 | andi $26, $26, 0x7C /* $26 <= PTI_INDEX * 4 */ |
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230 | addi $27, $14, 0x180 /* $27 <= &PTI_ACK[0] */ |
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231 | add $27, $27, $26 /* $27 <= &PTI_ACK[PTI_INDEX] */ |
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232 | lw $0, ($27) /* acknowledge XICU PTI */ |
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233 | la $27, _interrupt_vector |
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234 | addu $26, $26, $27 |
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235 | lw $26, ($26) /* read ISR address */ |
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236 | jalr $26 /* call ISR */ |
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237 | nop |
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238 | j _int_restore /* return from INT handler */ |
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239 | nop |
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240 | |
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241 | /* The HWI handler get HWI index */ |
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242 | /* and call the corresponding ISR */ |
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243 | _int_HWI: |
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244 | srl $26, $15, 14 /* $26 <= PRIO >> 14 */ |
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245 | andi $26, $26, 0x7C /* $26 <= HWI_INDEX * 4 */ |
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246 | la $27, _interrupt_vector |
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247 | addu $26, $26, $27 /* $26 <= &ISR[HWI_INDEX */ |
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248 | lw $26, ($26) /* read ISR address */ |
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249 | jalr $26 /* call ISR */ |
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250 | nop |
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251 | j _int_restore /* return from INT handler */ |
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252 | nop |
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253 | |
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254 | /* The WTI handler get WTI index, */ |
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255 | /* acknowledge the WTI register */ |
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256 | /* and call the corresponding ISR */ |
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257 | _int_WTI: |
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258 | srl $26, $15, 22 /* $26 <= PRIO >> 22 */ |
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259 | andi $26, $26, 0x7C /* $26 <= WTI_INDEX * 4 */ |
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260 | add $27, $14, $26 /* $27 <= &WTI_REG[WTI_INDEX] */ |
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261 | lw $0, ($27) /* acknowledge XICU WTI */ |
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262 | la $27, _interrupt_vector |
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263 | addu $26, $26, $27 /* $26 <= &ISR[WTI_INDEX] */ |
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264 | lw $26, ($26) /* read ISR address */ |
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265 | jalr $26 /* call ISR */ |
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266 | nop |
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267 | j _int_restore /* return from INT handler */ |
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268 | nop |
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269 | |
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270 | /* The default ISR is called when no specific ISR has been installed */ |
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271 | /* in the interrupt vector. It simply displays a message on TTY0 */ |
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272 | |
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273 | isr_default: |
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274 | addiu $29, $29, -20 /* get space in stack */ |
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275 | sw $31, 16($29) /* to save the return address */ |
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276 | la $4, _msg_default /* $4 <= string address */ |
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277 | addi $5, $0, 36 /* $5 <= string length */ |
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278 | li $6, 0 /* $6 <= TTY0 */ |
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279 | jal _tty_write |
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280 | lw $31, 16($29) /* restore return address */ |
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281 | addiu $29, $29, 20 /* free space */ |
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282 | jr $31 /* returns to interrupt handler */ |
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283 | |
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284 | /**************************************************************** |
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285 | * Interrupt Vector Table (indexed by interrupt index) |
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286 | * 32 words corresponding to 32 ISR addresses |
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287 | ****************************************************************/ |
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288 | _interrupt_vector: |
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289 | .word isr_default /* ISR 0 */ |
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290 | .word isr_default /* ISR 1 */ |
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291 | .word isr_default /* ISR 2 */ |
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292 | .word isr_default /* ISR 3 */ |
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293 | .word isr_default /* ISR 4 */ |
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294 | .word isr_default /* ISR 5 */ |
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295 | .word isr_default /* ISR 6 */ |
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296 | .word isr_default /* ISR 7 */ |
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297 | .word isr_default /* ISR 8 */ |
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298 | .word isr_default /* ISR 9 */ |
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299 | .word isr_default /* ISR 10 */ |
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300 | .word isr_default /* ISR 11 */ |
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301 | .word isr_default /* ISR 12 */ |
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302 | .word isr_default /* ISR 13 */ |
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303 | .word isr_default /* ISR 14 */ |
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304 | .word isr_default /* ISR 15 */ |
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305 | .word isr_default /* ISR 16 */ |
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306 | .word isr_default /* ISR 17 */ |
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307 | .word isr_default /* ISR 18 */ |
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308 | .word isr_default /* ISR 19 */ |
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309 | .word isr_default /* ISR 20 */ |
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310 | .word isr_default /* ISR 21 */ |
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311 | .word isr_default /* ISR 22 */ |
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312 | .word isr_default /* ISR 23 */ |
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313 | .word isr_default /* ISR 24 */ |
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314 | .word isr_default /* ISR 25 */ |
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315 | .word isr_default /* ISR 26 */ |
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316 | .word isr_default /* ISR 27 */ |
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317 | .word isr_default /* ISR 28 */ |
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318 | .word isr_default /* ISR 29 */ |
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319 | .word isr_default /* ISR 30 */ |
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320 | .word isr_default /* ISR 31 */ |
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321 | |
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322 | .end _int_handler |
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323 | |
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324 | /**************************************************************** |
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325 | * Exception Handler |
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326 | * Same code for all fatal exceptions : |
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327 | * Print the exception type and the values of EPC & BAR |
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328 | * on the TTY correspondintg to the processor PROCID, |
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329 | * and the user program is killed. |
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330 | ****************************************************************/ |
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331 | .ent _exc_handler |
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332 | |
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333 | _exc_handler: |
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334 | _cause_bp: |
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335 | _cause_ukn: |
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336 | _cause_ri: |
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337 | _cause_ovf: |
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338 | _cause_adel: |
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339 | _cause_ades: |
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340 | _cause_ibe: |
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341 | _cause_dbe: |
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342 | _cause_cpu: |
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343 | mfc0 $26, $13 /* $26 <= CR */ |
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344 | andi $26, $26, 0x3C /* $26 <= _cause_index * 4 */ |
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345 | la $27, _mess_causes /* mess_cause table base address */ |
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346 | addu $27, $26, $27 /* $26 <= message base address */ |
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347 | |
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348 | /* take the lock on TTY0 */ |
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349 | li $4, 0 |
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350 | jal _tty_get_lock |
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351 | nop |
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352 | |
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353 | /* display exception type */ |
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354 | lw $4, ($27) /* $4 <= message address */ |
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355 | li $5, 36 /* $5 <= message length */ |
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356 | li $6, 0 /* $6 <= TTY0 */ |
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357 | jal _tty_write |
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358 | nop |
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359 | |
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360 | /* display EPC value */ |
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361 | la $4, _msg_epc /* $4 <= message address */ |
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362 | li $5, 8 /* $5 <= message length */ |
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363 | li $6, 0 /* $6 <= TTY0 */ |
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364 | jal _tty_write |
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365 | nop |
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366 | |
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367 | mfc0 $4, $14 /* $4 <= EPC value */ |
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368 | la $5, _itoa_buffer /* $5 <= buffer address */ |
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369 | addiu $5, $5, 2 /* skip 0x prefix */ |
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370 | jal _itoa_hex /* fill buffer */ |
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371 | nop |
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372 | |
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373 | la $4, _itoa_buffer /* $4 <= buffer address */ |
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374 | li $5, 10 /* $5 <= buffer length */ |
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375 | li $6, 0 /* $6 <= TTY0 */ |
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376 | jal _tty_write |
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377 | nop |
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378 | |
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379 | /* display BAR value */ |
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380 | la $4, _msg_bar /* $4 <= message address */ |
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381 | li $5, 8 /* $5 <= message length */ |
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382 | li $6, 0 /* $6 <= TTY0 */ |
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383 | jal _tty_write |
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384 | nop |
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385 | |
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386 | mfc0 $4, $8 /* $4 <= BAR value */ |
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387 | la $5, _itoa_buffer /* $5 <= buffer address */ |
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388 | addiu $5, $5, 2 /* skip 0x prefix */ |
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389 | jal _itoa_hex /* fill buffer */ |
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390 | nop |
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391 | |
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392 | la $4, _itoa_buffer /* $4 <= message address */ |
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393 | li $5, 10 /* $5 <= message length */ |
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394 | li $6, 0 /* $6 <= TTY0 */ |
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395 | jal _tty_write |
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396 | nop |
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397 | |
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398 | |
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399 | /* release the lock on TTY0 */ |
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400 | li $4, 0 |
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401 | jal _tty_get_lock |
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402 | nop |
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403 | |
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404 | j _exit /* kill user program */ |
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405 | |
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406 | /* Exceptions Messages table (indexed by XCODE) */ |
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407 | _mess_causes: |
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408 | .word _msg_ukncause |
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409 | .word _msg_ukncause |
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410 | .word _msg_ukncause |
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411 | .word _msg_ukncause |
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412 | .word _msg_adel |
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413 | .word _msg_ades |
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414 | .word _msg_ibe |
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415 | .word _msg_dbe |
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416 | .word _msg_ukncause |
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417 | .word _msg_bp |
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418 | .word _msg_ri |
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419 | .word _msg_cpu |
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420 | .word _msg_ovf |
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421 | .word _msg_ukncause |
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422 | .word _msg_ukncause |
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423 | .word _msg_ukncause |
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424 | |
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425 | /******************************************************************** |
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426 | * All messages |
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427 | * Messages length are fixed : 8 or 36 characters... |
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428 | ********************************************************************/ |
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429 | _msg_bar: .asciiz "\nBAR = " |
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430 | _msg_epc: .asciiz "\nEPC = " |
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431 | _msg_default: .asciiz "\n\n !!! Default ISR !!! \n" |
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432 | _msg_uknsyscall: .asciiz "\n\n !!! Undefined System Call !!! \n" |
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433 | _msg_ukncause: .asciiz "\n\nException : strange unknown cause\n" |
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434 | _msg_adel: .asciiz "\n\nException : illegal read address \n" |
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435 | _msg_ades: .asciiz "\n\nException : illegal write address\n" |
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436 | _msg_ibe: .asciiz "\n\nException : inst bus error \n" |
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437 | _msg_dbe: .asciiz "\n\nException : data bus error \n" |
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438 | _msg_bp: .asciiz "\n\nException : breakpoint \n" |
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439 | _msg_ri: .asciiz "\n\nException : reserved instruction \n" |
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440 | _msg_ovf: .asciiz "\n\nException : arithmetic overflow \n" |
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441 | _msg_cpu: .asciiz "\n\nException : illegal coproc access\n" |
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442 | |
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443 | .end _exc_handler |
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444 | |
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445 | |
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