1/*
2 * This file is part of ltrace.
3 *
4 * Copyright (C) 2007 by Instituto Nokia de Tecnologia (INdT)
5 *
6 * Author: Anderson Lizardo <anderson.lizardo@indt.org.br>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * version 2 as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20 * 02110-1301 USA
21 *
22 * Modified from sysdeps/linux-gnu/breakpoint.c and added ARM Thumb support.
23 */
24
25#include <sys/ptrace.h>
26#include <sys/types.h>
27
28#include "config.h"
29#include "breakpoint.h"
30#include "debug.h"
31#include "proc.h"
32
33void
34arch_enable_breakpoint(pid_t pid, struct breakpoint *sbp)
35{
36	unsigned int i, j;
37	const unsigned char break_insn[] = BREAKPOINT_VALUE;
38	const unsigned char thumb_break_insn[] = THUMB_BREAKPOINT_VALUE;
39
40	debug(1, "arch_enable_breakpoint(%d,%p)", pid, sbp->addr);
41
42	for (i = 0; i < 1 + ((BREAKPOINT_LENGTH - 1) / sizeof(long)); i++) {
43		union _ { long l; unsigned char b[SIZEOF_LONG]; };
44		union _ orig, current;
45		unsigned char *bytes = current.b;
46		for (j = 0; j < sizeof(long); j++) {
47			orig.b[j] = sbp->orig_value[i * sizeof(long) + j];
48		}
49		current.l = ptrace(PTRACE_PEEKTEXT, pid, sbp->addr + i * sizeof(long), 0);
50
51		debug(2, "current = 0x%lx, orig_value = 0x%lx, thumb_mode = %d",
52		      current.l, orig.l, sbp->arch.thumb_mode);
53		for (j = 0; j < sizeof(long) && i * sizeof(long) + j < BREAKPOINT_LENGTH; j++) {
54
55			sbp->orig_value[i * sizeof(long) + j] = bytes[j];
56			if (!sbp->arch.thumb_mode) {
57				bytes[j] = break_insn[i * sizeof(long) + j];
58			}
59			else if (j < THUMB_BREAKPOINT_LENGTH) {
60				bytes[j] = thumb_break_insn[i * sizeof(long) + j];
61			}
62		}
63		ptrace(PTRACE_POKETEXT, pid, sbp->addr + i * sizeof(long),
64		       (void *)current.l);
65	}
66}
67
68void
69arch_disable_breakpoint(pid_t pid, const struct breakpoint *sbp)
70{
71	unsigned int i, j;
72
73	debug(1, "arch_disable_breakpoint(%d,%p)", pid, sbp->addr);
74
75	for (i = 0; i < 1 + ((BREAKPOINT_LENGTH - 1) / sizeof(long)); i++) {
76		union _ { long l; unsigned char b[SIZEOF_LONG]; };
77		union _ orig, current;
78		unsigned char *bytes = current.b;
79		for (j = 0; j < sizeof(long); j++) {
80			orig.b[j] = sbp->orig_value[i * sizeof(long) + j];
81		}
82		current.l = ptrace(PTRACE_PEEKTEXT, pid, sbp->addr + i * sizeof(long), 0);
83
84		debug(2, "current = 0x%lx, orig_value = 0x%lx, thumb_mode = %d",
85		      current.l, orig.l, sbp->arch.thumb_mode);
86		for (j = 0; j < sizeof(long) && i * sizeof(long) + j < BREAKPOINT_LENGTH; j++) {
87			bytes[j] = sbp->orig_value[i * sizeof(long) + j];
88		}
89		ptrace(PTRACE_POKETEXT, pid, sbp->addr + i * sizeof(long),
90		       (void *)current.l);
91	}
92}
93
94int
95arch_breakpoint_init(struct process *proc, struct breakpoint *sbp)
96{
97	/* XXX double cast  */
98	sbp->arch.thumb_mode = ((uintptr_t)sbp->addr) & 1;
99	if (sbp->arch.thumb_mode)
100		/* XXX double cast */
101		sbp->addr = (arch_addr_t)((uintptr_t)sbp->addr & ~1);
102	return 0;
103}
104
105void
106arch_breakpoint_destroy(struct breakpoint *sbp)
107{
108}
109
110int
111arch_breakpoint_clone(struct breakpoint *retp, struct breakpoint *sbp)
112{
113	retp->arch.thumb_mode = sbp->arch.thumb_mode;
114	return 0;
115}
116