| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * This file is subject to the terms and conditions of the GNU General Public |
| 3 | * License. See the file "COPYING" in the main directory of this archive |
| 4 | * for more details. |
| 5 | * |
| 6 | * Kernel debug stuff to use the Watch registers. |
| 7 | * Useful to find stack overflows, dangling pointers etc. |
| 8 | * |
| 9 | * Copyright (C) 1995, 1996, 1999 by Ralf Baechle |
| 10 | */ |
| 11 | #include <asm/asm.h> |
| 12 | #include <asm/mipsregs.h> |
| 13 | #include <asm/regdef.h> |
| 14 | |
| 15 | .set noreorder |
| 16 | /* |
| 17 | * Parameter: a0 - logic address to watch |
| 18 | * Currently only KSEG0 addresses are allowed! |
| 19 | * a1 - set bit #1 to trap on load references |
| 20 | * bit #0 to trap on store references |
| 21 | * Results : none |
| 22 | */ |
| 23 | LEAF(__watch_set) |
| 24 | li t0, 0x80000000 |
| 25 | subu a0, t0 |
| 26 | ori a0, 7 |
| 27 | xori a0, 7 |
| 28 | or a0, a1 |
| 29 | mtc0 a0, CP0_WATCHLO |
| 30 | sw a0, watch_savelo |
| 31 | |
| 32 | jr ra |
| 33 | mtc0 zero, CP0_WATCHHI |
| 34 | END(__watch_set) |
| 35 | |
| 36 | /* |
| 37 | * Parameter: none |
| 38 | * Results : none |
| 39 | */ |
| 40 | LEAF(__watch_clear) |
| 41 | jr ra |
| 42 | mtc0 zero, CP0_WATCHLO |
| 43 | END(__watch_clear) |
| 44 | |
| 45 | /* |
| 46 | * Parameter: none |
| 47 | * Results : none |
| 48 | */ |
| 49 | LEAF(__watch_reenable) |
| 50 | lw t0, watch_savelo |
| 51 | jr ra |
| 52 | mtc0 t0, CP0_WATCHLO |
| 53 | END(__watch_reenable) |
| 54 | |
| 55 | /* |
| 56 | * Saved value of the c0_watchlo register for watch_reenable() |
| 57 | */ |
| 58 | .data |
| 59 | watch_savelo: .word 0 |
| 60 | .text |