1 | /* |
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2 | * load/store bus fault exception test: we can restart the jump when the |
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3 | * instruction in the delay slot takes a fault. |
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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 | |
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10 | .text |
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11 | .globl _start |
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12 | _start: |
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13 | .set noreorder |
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14 | la k0, TTY_BASE |
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15 | la k1, EXIT_BASE |
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16 | la sp, 0x00400000 - 16 |
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17 | |
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18 | PRINT(startstr) |
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19 | |
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20 | /* reset cop0 status (keep BEV) */ |
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21 | lui a0, 0x0040; |
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22 | mtc0 a0, COP0_STATUS |
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23 | |
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24 | la a0, pte1 |
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25 | srl a0, a0, 13 |
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26 | mtc2 a0, VC_PTPR |
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27 | nop |
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28 | |
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29 | li a0, VC_TLB_EN_ITLB | VC_TLB_EN_DTLB | VC_TLB_EN_ICACHE | VC_TLB_EN_DCACHE |
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30 | mtc2 a0, VC_TLB_EN |
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31 | |
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32 | PRINT(mmustr) |
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33 | |
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34 | /* 0x00000000 not mapped yet: we fault, load the MMU and retry */ |
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35 | move a1, zero |
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36 | la s0, testval |
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37 | jal doload |
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38 | move a0, s0 |
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39 | PRINTX |
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40 | PUTCHAR(':') |
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41 | PUTCHAR(' ') |
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42 | move a0, a1 |
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43 | PRINTX |
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44 | PUTCHAR('\n') |
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45 | |
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46 | /* we should get there */ |
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47 | EXIT(0) |
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48 | |
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49 | .globl doload |
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50 | doload: |
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51 | nop |
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52 | nop |
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53 | jr ra |
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54 | lw a1, 0(s0) /* this should trigger the exception */ |
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55 | |
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56 | /* we should not get there */ |
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57 | EXIT(1) |
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58 | |
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59 | .globl excep |
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60 | excep: |
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61 | .set noreorder |
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62 | /* don't clobber a0 and ra */ |
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63 | addiu sp, sp, -8 |
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64 | sw a0, 4(sp) |
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65 | sw ra, 8(sp) |
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66 | PRINT(statusstr) |
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67 | mfc0 a0, COP0_STATUS |
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68 | PRINTX |
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69 | |
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70 | PRINT(causestr) |
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71 | mfc0 a0, COP0_CAUSE |
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72 | PRINTX |
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73 | |
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74 | PRINT(pcstr) |
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75 | mfc0 a0, COP0_EXPC |
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76 | PRINTX |
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77 | |
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78 | PRINT(badvastr) |
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79 | mfc0 a0, COP_0_BADVADDR |
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80 | PRINTX |
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81 | |
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82 | PUTCHAR('\n') |
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83 | /* map VA 0 at PA 0: just copy entry for 0x00200000 */ |
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84 | la t0, pte1 + 0x00200000 |
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85 | lw a0, 4(t0) |
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86 | sw a0, 0(t0) |
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87 | /* mtc2 zero, VC_DTLB_INVAL */ |
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88 | lw a0, 4(sp) |
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89 | lw ra, 8(sp) |
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90 | addiu sp, sp, 8 |
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91 | eret |
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92 | |
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93 | .rodata: |
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94 | statusstr: .ascii "status \0" |
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95 | causestr: .ascii " cause \0" |
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96 | pcstr: .ascii " pc \0" |
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97 | badvastr: .ascii " badva \0" |
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98 | mmustr: .ascii "mmu started\n\0" |
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99 | startstr: .ascii "start\n\0" |
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100 | |
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101 | .org EXCEP_ADDRESS - BOOT_ADDRESS |
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102 | .globl evect |
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103 | evect: |
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104 | j excep |
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105 | nop |
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106 | .data |
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107 | .word MAGIC1 |
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108 | testval: |
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109 | .word MAGIC2 |
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110 | .globl pte1 |
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111 | pte1: |
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112 | .align 13 |
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113 | .word 0x0 /* map PA 0 at VA 0 */ |
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114 | .word PTE1_V | PTE1_C | PTE1_W | 0x0 /* map PA 0 at VA 0x00200000 */ |
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115 | .org pte1 + (BOOT_ADDRESS >> 21) * 4 |
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116 | .word PTE1_V | PTE1_C | PTE1_X | (BOOT_ADDRESS >> 21) /* map PA 0xbfc00000 at VA 0xbfc00000 */ |
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117 | .org pte1 + (TTY_BASE >> 21) * 4 |
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118 | .word PTE1_V | PTE1_W | (TTY_BASE >> 21) /* map PA 0xd0200000 at VA 0xd0200000 */ |
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119 | .org pte1 + (EXIT_BASE >> 21) * 4 |
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120 | .word PTE1_V | PTE1_W | (EXIT_BASE >> 21) /* map PA 0xe0000000 at VA 0xe0000000 */ |
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121 | .org pte1 + 8192 |
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122 | .word 0 |
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123 | |
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