regs.c revision e99af270a60891e68d465c4cd97dbe29cd1a05e4 
1/*
2 * This file is part of ltrace.
3 * Copyright (C) 1998,2002,2004,2008,2009 Juan Cespedes
4 * Copyright (C) 2009 Juan Cespedes
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation; either version 2 of the
9 * License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19 * 02110-1301 USA
20 */
21
22#include "config.h"
23
24#include <sys/types.h>
25#include <sys/ptrace.h>
26#include <asm/ptrace.h>
27
28#include "proc.h"
29#include "common.h"
30
31#if (!defined(PTRACE_PEEKUSER) && defined(PTRACE_PEEKUSR))
32# define PTRACE_PEEKUSER PTRACE_PEEKUSR
33#endif
34
35#if (!defined(PTRACE_POKEUSER) && defined(PTRACE_POKEUSR))
36# define PTRACE_POKEUSER PTRACE_POKEUSR
37#endif
38
39#define off_pc ((void *)60)
40#define off_lr ((void *)56)
41#define off_sp ((void *)52)
42
43void *
44get_instruction_pointer(Process *proc) {
45	return (void *)ptrace(PTRACE_PEEKUSER, proc->pid, off_pc, 0);
46}
47
48void
49set_instruction_pointer(Process *proc, void *addr) {
50	ptrace(PTRACE_POKEUSER, proc->pid, off_pc, addr);
51}
52
53void *
54get_stack_pointer(Process *proc) {
55	return (void *)ptrace(PTRACE_PEEKUSER, proc->pid, off_sp, 0);
56}
57
58/* really, this is given the *stack_pointer expecting
59 * a CISC architecture; in our case, we don't need that */
60void *
61get_return_addr(Process *proc, void *stack_pointer) {
62	long addr = ptrace(PTRACE_PEEKUSER, proc->pid, off_lr, 0);
63
64	/* Remember & unset the thumb mode bit.  XXX This is really a
65	 * bit of a hack, as we assume that the following
66	 * insert_breakpoint call will be related to this address.
67	 * This interface should really be get_return_breakpoint, or
68	 * maybe install_return_breakpoint.  */
69	proc->thumb_mode = addr & 1;
70	if (proc->thumb_mode)
71		addr &= ~1;
72
73	return (void *)addr;
74}
75
76void
77set_return_addr(Process *proc, void *addr) {
78	long iaddr = (int)addr | proc->thumb_mode;
79	ptrace(PTRACE_POKEUSER, proc->pid, off_lr, (void *)iaddr);
80}
81