Commit | Line | Data |
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c906108c | 1 | /* Simulate breakpoints by patching locations in the target system, for GDB. |
f4f9705a | 2 | |
e2882c85 | 3 | Copyright (C) 1990-2018 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 | { |
ba7b109b | 40 | CORE_ADDR addr = bp_tgt->placed_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. */ | |
579c6ad9 | 47 | bp = gdbarch_sw_breakpoint_from_kind (gdbarch, bp_tgt->kind, &bplen); |
0d5ed153 | 48 | |
35c63cd8 JB |
49 | /* Save the memory contents in the shadow_contents buffer and then |
50 | write the breakpoint instruction. */ | |
224c3ddb | 51 | readbuf = (gdb_byte *) alloca (bplen); |
0d5ed153 | 52 | val = target_read_memory (addr, readbuf, bplen); |
c906108c | 53 | if (val == 0) |
35c63cd8 | 54 | { |
68901c4d PA |
55 | /* These must be set together, either before or after the shadow |
56 | read, so that if we're "reinserting" a breakpoint that | |
57 | doesn't have a shadow yet, the breakpoint masking code inside | |
58 | target_read_memory doesn't mask out this breakpoint using an | |
59 | unfilled shadow buffer. The core may be trying to reinsert a | |
60 | permanent breakpoint, for targets that support breakpoint | |
61 | conditions/commands on the target side for some types of | |
62 | breakpoints, such as target remote. */ | |
63 | bp_tgt->shadow_len = bplen; | |
0d5ed153 | 64 | memcpy (bp_tgt->shadow_contents, readbuf, bplen); |
68901c4d | 65 | |
0d5ed153 | 66 | val = target_write_raw_memory (addr, bp, bplen); |
35c63cd8 | 67 | } |
c906108c SS |
68 | |
69 | return val; | |
70 | } | |
71 | ||
72 | ||
73 | int | |
ae4b2284 MD |
74 | default_memory_remove_breakpoint (struct gdbarch *gdbarch, |
75 | struct bp_target_info *bp_tgt) | |
c906108c | 76 | { |
cd6c3b4f YQ |
77 | int bplen; |
78 | ||
579c6ad9 | 79 | gdbarch_sw_breakpoint_from_kind (gdbarch, bp_tgt->kind, &bplen); |
cd6c3b4f | 80 | |
f0ba3972 | 81 | return target_write_raw_memory (bp_tgt->placed_address, bp_tgt->shadow_contents, |
cd6c3b4f | 82 | bplen); |
c906108c | 83 | } |
917317f4 JM |
84 | |
85 | ||
917317f4 | 86 | int |
3db08215 | 87 | memory_insert_breakpoint (struct target_ops *ops, struct gdbarch *gdbarch, |
a6d9a66e | 88 | struct bp_target_info *bp_tgt) |
917317f4 | 89 | { |
a6d9a66e | 90 | return gdbarch_memory_insert_breakpoint (gdbarch, bp_tgt); |
917317f4 JM |
91 | } |
92 | ||
917317f4 | 93 | int |
3db08215 | 94 | memory_remove_breakpoint (struct target_ops *ops, struct gdbarch *gdbarch, |
73971819 PA |
95 | struct bp_target_info *bp_tgt, |
96 | enum remove_bp_reason reason) | |
917317f4 | 97 | { |
a6d9a66e | 98 | return gdbarch_memory_remove_breakpoint (gdbarch, bp_tgt); |
917317f4 | 99 | } |
08351840 PA |
100 | |
101 | int | |
102 | memory_validate_breakpoint (struct gdbarch *gdbarch, | |
103 | struct bp_target_info *bp_tgt) | |
104 | { | |
105 | CORE_ADDR addr = bp_tgt->placed_address; | |
106 | const gdb_byte *bp; | |
107 | int val; | |
108 | int bplen; | |
109 | gdb_byte cur_contents[BREAKPOINT_MAX]; | |
08351840 PA |
110 | |
111 | /* Determine appropriate breakpoint contents and size for this | |
112 | address. */ | |
113 | bp = gdbarch_breakpoint_from_pc (gdbarch, &addr, &bplen); | |
114 | ||
cd6c3b4f | 115 | if (bp == NULL) |
08351840 PA |
116 | return 0; |
117 | ||
118 | /* Make sure we see the memory breakpoints. */ | |
cb85b21b TT |
119 | scoped_restore restore_memory |
120 | = make_scoped_restore_show_memory_breakpoints (1); | |
08351840 PA |
121 | val = target_read_memory (addr, cur_contents, bplen); |
122 | ||
123 | /* If our breakpoint is no longer at the address, this means that | |
124 | the program modified the code on us, so it is wrong to put back | |
125 | the old value. */ | |
cb85b21b | 126 | return (val == 0 && memcmp (bp, cur_contents, bplen) == 0); |
08351840 | 127 | } |