Commit | Line | Data |
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c906108c | 1 | /* Simulate breakpoints by patching locations in the target system, for GDB. |
f4f9705a | 2 | |
618f726f | 3 | Copyright (C) 1990-2016 Free Software Foundation, Inc. |
f4f9705a | 4 | |
c906108c SS |
5 | Contributed by Cygnus Support. Written by John Gilmore. |
6 | ||
c5aa993b | 7 | This file is part of GDB. |
c906108c | 8 | |
c5aa993b JM |
9 | This program is free software; you can redistribute it and/or modify |
10 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 11 | the Free Software Foundation; either version 3 of the License, or |
c5aa993b | 12 | (at your option) any later version. |
c906108c | 13 | |
c5aa993b JM |
14 | This program is distributed in the hope that it will be useful, |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
c906108c | 18 | |
c5aa993b | 19 | You should have received a copy of the GNU General Public License |
a9762ec7 | 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
c906108c SS |
21 | |
22 | #include "defs.h" | |
c906108c SS |
23 | #include "symtab.h" |
24 | #include "breakpoint.h" | |
25 | #include "inferior.h" | |
26 | #include "target.h" | |
8181d85f DJ |
27 | /* Insert a breakpoint on targets that don't have any better |
28 | breakpoint support. We read the contents of the target location | |
29 | and stash it, then overwrite it with a breakpoint instruction. | |
30 | BP_TGT->placed_address is the target location in the target | |
31 | machine. BP_TGT->shadow_contents is some memory allocated for | |
32 | saving the target contents. It is guaranteed by the caller to be | |
33 | long enough to save BREAKPOINT_LEN bytes (this is accomplished via | |
34 | BREAKPOINT_MAX). */ | |
c906108c SS |
35 | |
36 | int | |
ae4b2284 MD |
37 | default_memory_insert_breakpoint (struct gdbarch *gdbarch, |
38 | struct bp_target_info *bp_tgt) | |
c906108c | 39 | { |
0d5ed153 | 40 | CORE_ADDR addr = bp_tgt->reqstd_address; |
f4f9705a | 41 | const unsigned char *bp; |
35c63cd8 | 42 | gdb_byte *readbuf; |
0d5ed153 MR |
43 | int bplen; |
44 | int val; | |
c906108c SS |
45 | |
46 | /* Determine appropriate breakpoint contents and size for this address. */ | |
0d5ed153 | 47 | bp = gdbarch_breakpoint_from_pc (gdbarch, &addr, &bplen); |
c906108c | 48 | if (bp == NULL) |
8a3fe4f8 | 49 | error (_("Software breakpoints not implemented for this target.")); |
c906108c | 50 | |
0d5ed153 MR |
51 | bp_tgt->placed_address = addr; |
52 | bp_tgt->placed_size = bplen; | |
53 | ||
35c63cd8 JB |
54 | /* Save the memory contents in the shadow_contents buffer and then |
55 | write the breakpoint instruction. */ | |
224c3ddb | 56 | readbuf = (gdb_byte *) alloca (bplen); |
0d5ed153 | 57 | val = target_read_memory (addr, readbuf, bplen); |
c906108c | 58 | if (val == 0) |
35c63cd8 | 59 | { |
68901c4d PA |
60 | /* These must be set together, either before or after the shadow |
61 | read, so that if we're "reinserting" a breakpoint that | |
62 | doesn't have a shadow yet, the breakpoint masking code inside | |
63 | target_read_memory doesn't mask out this breakpoint using an | |
64 | unfilled shadow buffer. The core may be trying to reinsert a | |
65 | permanent breakpoint, for targets that support breakpoint | |
66 | conditions/commands on the target side for some types of | |
67 | breakpoints, such as target remote. */ | |
68 | bp_tgt->shadow_len = bplen; | |
0d5ed153 | 69 | memcpy (bp_tgt->shadow_contents, readbuf, bplen); |
68901c4d | 70 | |
0d5ed153 | 71 | val = target_write_raw_memory (addr, bp, bplen); |
35c63cd8 | 72 | } |
c906108c SS |
73 | |
74 | return val; | |
75 | } | |
76 | ||
77 | ||
78 | int | |
ae4b2284 MD |
79 | default_memory_remove_breakpoint (struct gdbarch *gdbarch, |
80 | struct bp_target_info *bp_tgt) | |
c906108c | 81 | { |
f0ba3972 PA |
82 | return target_write_raw_memory (bp_tgt->placed_address, bp_tgt->shadow_contents, |
83 | bp_tgt->placed_size); | |
c906108c | 84 | } |
917317f4 JM |
85 | |
86 | ||
917317f4 | 87 | int |
3db08215 | 88 | memory_insert_breakpoint (struct target_ops *ops, struct gdbarch *gdbarch, |
a6d9a66e | 89 | struct bp_target_info *bp_tgt) |
917317f4 | 90 | { |
a6d9a66e | 91 | return gdbarch_memory_insert_breakpoint (gdbarch, bp_tgt); |
917317f4 JM |
92 | } |
93 | ||
917317f4 | 94 | int |
3db08215 | 95 | memory_remove_breakpoint (struct target_ops *ops, struct gdbarch *gdbarch, |
73971819 PA |
96 | struct bp_target_info *bp_tgt, |
97 | enum remove_bp_reason reason) | |
917317f4 | 98 | { |
a6d9a66e | 99 | return gdbarch_memory_remove_breakpoint (gdbarch, bp_tgt); |
917317f4 | 100 | } |
08351840 PA |
101 | |
102 | int | |
103 | memory_validate_breakpoint (struct gdbarch *gdbarch, | |
104 | struct bp_target_info *bp_tgt) | |
105 | { | |
106 | CORE_ADDR addr = bp_tgt->placed_address; | |
107 | const gdb_byte *bp; | |
108 | int val; | |
109 | int bplen; | |
110 | gdb_byte cur_contents[BREAKPOINT_MAX]; | |
111 | struct cleanup *cleanup; | |
112 | int ret; | |
113 | ||
114 | /* Determine appropriate breakpoint contents and size for this | |
115 | address. */ | |
116 | bp = gdbarch_breakpoint_from_pc (gdbarch, &addr, &bplen); | |
117 | ||
118 | if (bp == NULL || bp_tgt->placed_size != bplen) | |
119 | return 0; | |
120 | ||
121 | /* Make sure we see the memory breakpoints. */ | |
122 | cleanup = make_show_memory_breakpoints_cleanup (1); | |
123 | val = target_read_memory (addr, cur_contents, bplen); | |
124 | ||
125 | /* If our breakpoint is no longer at the address, this means that | |
126 | the program modified the code on us, so it is wrong to put back | |
127 | the old value. */ | |
128 | ret = (val == 0 && memcmp (bp, cur_contents, bplen) == 0); | |
129 | ||
130 | do_cleanups (cleanup); | |
131 | return ret; | |
132 | } |