1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
|
/* Simulate breakpoints by patching locations in the target system, for GDB.
Copyright (C) 1990-2019 Free Software Foundation, Inc.
Contributed by Cygnus Support. Written by John Gilmore.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "symtab.h"
#include "breakpoint.h"
#include "inferior.h"
#include "target.h"
#include "gdbarch.h"
/* Insert a breakpoint on targets that don't have any better
breakpoint support. We read the contents of the target location
and stash it, then overwrite it with a breakpoint instruction.
BP_TGT->placed_address is the target location in the target
machine. BP_TGT->shadow_contents is some memory allocated for
saving the target contents. It is guaranteed by the caller to be
long enough to save BREAKPOINT_LEN bytes (this is accomplished via
BREAKPOINT_MAX). */
int
default_memory_insert_breakpoint (struct gdbarch *gdbarch,
struct bp_target_info *bp_tgt)
{
CORE_ADDR addr = bp_tgt->placed_address;
const unsigned char *bp;
gdb_byte *readbuf;
int bplen;
int val;
/* Determine appropriate breakpoint contents and size for this address. */
bp = gdbarch_sw_breakpoint_from_kind (gdbarch, bp_tgt->kind, &bplen);
/* Save the memory contents in the shadow_contents buffer and then
write the breakpoint instruction. */
readbuf = (gdb_byte *) alloca (bplen);
val = target_read_memory (addr, readbuf, bplen);
if (val == 0)
{
/* These must be set together, either before or after the shadow
read, so that if we're "reinserting" a breakpoint that
doesn't have a shadow yet, the breakpoint masking code inside
target_read_memory doesn't mask out this breakpoint using an
unfilled shadow buffer. The core may be trying to reinsert a
permanent breakpoint, for targets that support breakpoint
conditions/commands on the target side for some types of
breakpoints, such as target remote. */
bp_tgt->shadow_len = bplen;
memcpy (bp_tgt->shadow_contents, readbuf, bplen);
val = target_write_raw_memory (addr, bp, bplen);
}
return val;
}
int
default_memory_remove_breakpoint (struct gdbarch *gdbarch,
struct bp_target_info *bp_tgt)
{
int bplen;
gdbarch_sw_breakpoint_from_kind (gdbarch, bp_tgt->kind, &bplen);
return target_write_raw_memory (bp_tgt->placed_address, bp_tgt->shadow_contents,
bplen);
}
int
memory_insert_breakpoint (struct target_ops *ops, struct gdbarch *gdbarch,
struct bp_target_info *bp_tgt)
{
return gdbarch_memory_insert_breakpoint (gdbarch, bp_tgt);
}
int
memory_remove_breakpoint (struct target_ops *ops, struct gdbarch *gdbarch,
struct bp_target_info *bp_tgt,
enum remove_bp_reason reason)
{
return gdbarch_memory_remove_breakpoint (gdbarch, bp_tgt);
}
int
memory_validate_breakpoint (struct gdbarch *gdbarch,
struct bp_target_info *bp_tgt)
{
CORE_ADDR addr = bp_tgt->placed_address;
const gdb_byte *bp;
int val;
int bplen;
gdb_byte cur_contents[BREAKPOINT_MAX];
/* Determine appropriate breakpoint contents and size for this
address. */
bp = gdbarch_breakpoint_from_pc (gdbarch, &addr, &bplen);
if (bp == NULL)
return 0;
/* Make sure we see the memory breakpoints. */
scoped_restore restore_memory
= make_scoped_restore_show_memory_breakpoints (1);
val = target_read_memory (addr, cur_contents, bplen);
/* If our breakpoint is no longer at the address, this means that
the program modified the code on us, so it is wrong to put back
the old value. */
return (val == 0 && memcmp (bp, cur_contents, bplen) == 0);
}
|
GitWeb