[520] | 1 | /* |
---|
| 2 | * load/store bus fault exception test: we can restart the jump when the |
---|
| 3 | * instruction in the delay slot takes a fault. |
---|
| 4 | * We use the MMU to cause fault |
---|
| 5 | */ |
---|
| 6 | #include <registers.h> |
---|
| 7 | #include <misc.h> |
---|
| 8 | #include <vcache.h> |
---|
| 9 | |
---|
| 10 | .text |
---|
| 11 | .globl _start |
---|
| 12 | _start: |
---|
| 13 | .set noreorder |
---|
| 14 | la k0, TTY_BASE |
---|
| 15 | la k1, EXIT_BASE |
---|
| 16 | la sp, 0x00400000 - 16 |
---|
| 17 | |
---|
| 18 | PRINT(startstr) |
---|
| 19 | |
---|
| 20 | /* reset cop0 status (keep BEV) */ |
---|
| 21 | lui a0, 0x0040; |
---|
| 22 | mtc0 a0, COP0_STATUS |
---|
| 23 | |
---|
| 24 | la a0, pte1 |
---|
| 25 | srl a0, a0, 13 |
---|
| 26 | mtc2 a0, VC_PTPR |
---|
| 27 | nop |
---|
| 28 | |
---|
| 29 | li a0, VC_TLB_EN_ITLB | VC_TLB_EN_DTLB | VC_TLB_EN_ICACHE | VC_TLB_EN_DCACHE |
---|
| 30 | mtc2 a0, VC_TLB_EN |
---|
| 31 | |
---|
| 32 | PRINT(mmustr) |
---|
| 33 | |
---|
| 34 | /* 0x00000000 not mapped yet: we fault, load the MMU and retry */ |
---|
| 35 | move a1, zero |
---|
| 36 | la s0, testval |
---|
| 37 | jal doload |
---|
| 38 | move a0, s0 |
---|
| 39 | PRINTX |
---|
| 40 | PUTCHAR(':') |
---|
| 41 | PUTCHAR(' ') |
---|
| 42 | move a0, a1 |
---|
| 43 | PRINTX |
---|
| 44 | PUTCHAR('\n') |
---|
| 45 | |
---|
| 46 | /* we should get there */ |
---|
| 47 | EXIT(0) |
---|
| 48 | |
---|
| 49 | .globl doload |
---|
| 50 | doload: |
---|
| 51 | nop |
---|
| 52 | nop |
---|
| 53 | jr ra |
---|
| 54 | lw a1, 0(s0) /* this should trigger the exception */ |
---|
| 55 | |
---|
| 56 | /* we should not get there */ |
---|
| 57 | EXIT(1) |
---|
| 58 | |
---|
| 59 | .globl excep |
---|
| 60 | excep: |
---|
| 61 | .set noreorder |
---|
| 62 | /* don't clobber a0 and ra */ |
---|
| 63 | addiu sp, sp, -8 |
---|
| 64 | sw a0, 4(sp) |
---|
| 65 | sw ra, 8(sp) |
---|
| 66 | PRINT(statusstr) |
---|
| 67 | mfc0 a0, COP0_STATUS |
---|
| 68 | PRINTX |
---|
| 69 | |
---|
| 70 | PRINT(causestr) |
---|
| 71 | mfc0 a0, COP0_CAUSE |
---|
| 72 | PRINTX |
---|
| 73 | |
---|
| 74 | PRINT(pcstr) |
---|
| 75 | mfc0 a0, COP0_EXPC |
---|
| 76 | PRINTX |
---|
| 77 | |
---|
| 78 | PRINT(badvastr) |
---|
| 79 | mfc0 a0, COP_0_BADVADDR |
---|
| 80 | PRINTX |
---|
| 81 | |
---|
| 82 | PUTCHAR('\n') |
---|
| 83 | /* map VA 0 at PA 0: just copy entry for 0x00200000 */ |
---|
| 84 | la t0, pte1 + 0x00200000 |
---|
| 85 | lw a0, 4(t0) |
---|
| 86 | sw a0, 0(t0) |
---|
| 87 | /* mtc2 zero, VC_DTLB_INVAL */ |
---|
| 88 | lw a0, 4(sp) |
---|
| 89 | lw ra, 8(sp) |
---|
| 90 | addiu sp, sp, 8 |
---|
| 91 | eret |
---|
| 92 | |
---|
| 93 | .rodata: |
---|
| 94 | statusstr: .ascii "status \0" |
---|
| 95 | causestr: .ascii " cause \0" |
---|
| 96 | pcstr: .ascii " pc \0" |
---|
| 97 | badvastr: .ascii " badva \0" |
---|
| 98 | mmustr: .ascii "mmu started\n\0" |
---|
| 99 | startstr: .ascii "start\n\0" |
---|
| 100 | |
---|
| 101 | .org EXCEP_ADDRESS - BOOT_ADDRESS |
---|
| 102 | .globl evect |
---|
| 103 | evect: |
---|
| 104 | j excep |
---|
| 105 | nop |
---|
| 106 | .data |
---|
| 107 | .word MAGIC1 |
---|
| 108 | testval: |
---|
| 109 | .word MAGIC2 |
---|
| 110 | .globl pte1 |
---|
| 111 | pte1: |
---|
| 112 | .align 13 |
---|
| 113 | .word 0x0 /* map PA 0 at VA 0 */ |
---|
| 114 | .word PTE1_V | PTE1_C | PTE1_W | 0x0 /* map PA 0 at VA 0x00200000 */ |
---|
| 115 | .org pte1 + (BOOT_ADDRESS >> 21) * 4 |
---|
| 116 | .word PTE1_V | PTE1_C | PTE1_X | (BOOT_ADDRESS >> 21) /* map PA 0xbfc00000 at VA 0xbfc00000 */ |
---|
| 117 | .org pte1 + (TTY_BASE >> 21) * 4 |
---|
| 118 | .word PTE1_V | PTE1_W | (TTY_BASE >> 21) /* map PA 0xd0200000 at VA 0xd0200000 */ |
---|
| 119 | .org pte1 + (EXIT_BASE >> 21) * 4 |
---|
| 120 | .word PTE1_V | PTE1_W | (EXIT_BASE >> 21) /* map PA 0xe0000000 at VA 0xe0000000 */ |
---|
| 121 | .org pte1 + 8192 |
---|
| 122 | .word 0 |
---|
| 123 | |
---|