1 | /* |
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2 | * ifetch bus fault exception test: we can restart the faulting instruction |
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3 | * when the fault occurs in the branch delay slot. |
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4 | * We use the MMU to cause fault. |
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5 | */ |
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6 | #include <registers.h> |
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7 | #include <misc.h> |
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8 | #include <vcache.h> |
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9 | .text |
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10 | .globl _start |
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11 | _start: |
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12 | .set noreorder |
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13 | la k0, TTY_BASE |
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14 | la k1, EXIT_BASE |
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15 | la sp, 0x00200000 - 16 |
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16 | |
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17 | PRINT(startstr) |
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18 | |
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19 | /* reset cop0 status (keep BEV) */ |
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20 | lui a0, 0x0040; |
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21 | mtc0 a0, COP0_STATUS |
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22 | |
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23 | la a0, pte1 |
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24 | srl a0, a0, 13 |
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25 | mtc2 a0, VC_PTPR |
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26 | nop |
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27 | |
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28 | li a0, VC_TLB_EN_ITLB | VC_TLB_EN_DTLB | VC_TLB_EN_ICACHE | VC_TLB_EN_DCACHE |
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29 | mtc2 a0, VC_TLB_EN |
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30 | |
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31 | PRINT(mmustr) |
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32 | |
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33 | move a1, zero |
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34 | la s0, testval |
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35 | jal doload |
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36 | move a0, s0 |
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37 | PRINTX |
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38 | PUTCHAR(':') |
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39 | PUTCHAR(' ') |
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40 | move a0, a1 |
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41 | PRINTX |
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42 | PUTCHAR('\n') |
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43 | |
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44 | /* we should get there */ |
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45 | EXIT(0) |
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46 | |
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47 | .globl excep |
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48 | excep: |
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49 | .set noreorder |
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50 | /* don't clobber a0 and ra */ |
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51 | addiu sp, sp, -8 |
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52 | sw a0, 4(sp) |
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53 | sw ra, 8(sp) |
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54 | |
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55 | PRINT(statusstr) |
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56 | mfc0 a0, COP0_STATUS |
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57 | PRINTX |
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58 | |
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59 | PRINT(causestr) |
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60 | mfc0 a0, COP0_CAUSE |
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61 | PRINTX |
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62 | |
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63 | PRINT(pcstr) |
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64 | mfc0 a0, COP0_EXPC |
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65 | PRINTX |
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66 | |
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67 | PRINT(badvastr) |
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68 | mfc0 a0, COP_0_BADVADDR |
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69 | PRINTX |
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70 | |
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71 | PUTCHAR('\n') |
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72 | /* map VA 0xbfc01000 at PA 0xbfc01000 */ |
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73 | la t0, pte2 + VADDR_TO_PTE2I(0xbfc01000) * 8 |
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74 | la a0, (0xbfc01000 >> PTE2_SHIFT) |
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75 | sw a0, 4(t0) |
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76 | la a0, (PTE2_V | PTE2_C | PTE2_X) |
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77 | sw a0, 0(t0) |
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78 | /* la a0, 0xbfc01000 |
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79 | mtc2 a0, VC_ITLB_INVAL */ |
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80 | |
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81 | lw a0, 4(sp) |
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82 | lw ra, 8(sp) |
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83 | addiu sp, sp, 8 |
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84 | eret |
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85 | |
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86 | .rodata: |
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87 | statusstr: .ascii "status \0" |
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88 | causestr: .ascii " cause \0" |
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89 | pcstr: .ascii " pc \0" |
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90 | badvastr: .ascii " badva \0" |
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91 | mmustr: .ascii "mmu started\n\0" |
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92 | startstr: .ascii "start\n\0" |
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93 | |
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94 | .org EXCEP_ADDRESS - BOOT_ADDRESS |
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95 | .globl evect |
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96 | evect: |
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97 | j excep |
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98 | nop |
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99 | /* |
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100 | * we use a ldscript trick here, to load this function at |
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101 | * the appropriate address |
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102 | */ |
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103 | .section .text2, "ax" |
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104 | .globl doload |
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105 | doload: |
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106 | jr ra |
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107 | lw a1, 0(s0) /* this should trigger the exception */ |
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108 | |
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109 | /* we should not get there */ |
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110 | nop |
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111 | nop |
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112 | EXIT(1) |
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113 | |
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114 | .data |
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115 | .word MAGIC1 |
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116 | testval: |
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117 | .word MAGIC2 |
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118 | .globl pte2 |
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119 | pte2: |
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120 | .align 12 |
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121 | .word PTE2_V | PTE2_C | PTE2_X |
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122 | .word BOOT_ADDRESS >> 12 |
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123 | .org pte2 + 4092 |
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124 | .globl pte1 |
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125 | pte1: |
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126 | .align 13 |
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127 | .word PTE1_V | PTE1_C | PTE1_W | 0x0 /* map PA 0 at VA 0 */ |
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128 | .word 0x0 |
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129 | .org pte1 + (BOOT_ADDRESS >> 21) * 4 |
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130 | .word PTE1_V | PTE1_T | (0x1000 >> 12) /* map PA 0xbfc00000 at VA 0xbfc00000 with 4k page: check real address of PTE2 !!! */ |
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131 | .org pte1 + (TTY_BASE >> 21) * 4 |
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132 | .word PTE1_V | PTE1_W | (TTY_BASE >> 21) /* map PA 0xd0200000 at VA 0xd0200000 */ |
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133 | .org pte1 + (EXIT_BASE >> 21) * 4 |
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134 | .word PTE1_V | PTE1_W | (EXIT_BASE >> 21) /* map PA 0xe0000000 at VA 0xe0000000 */ |
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135 | .org pte1 + 8192 |
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