/arch/mips/lib-32/watch.S

 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
59watch_savelo:	.word	0
60		.text