1 /* Simulate breakpoints by patching locations in the target system, for GDB.
3 Copyright (C) 1990-2013 Free Software Foundation, Inc.
5 Contributed by Cygnus Support. Written by John Gilmore.
7 This file is part of GDB.
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
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
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.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 /* This file is only useful if BREAKPOINT_FROM_PC is set. If not, we
28 #include "breakpoint.h"
31 #include "gdb_string.h"
34 /* Insert a breakpoint on targets that don't have any better
35 breakpoint support. We read the contents of the target location
36 and stash it, then overwrite it with a breakpoint instruction.
37 BP_TGT->placed_address is the target location in the target
38 machine. BP_TGT->shadow_contents is some memory allocated for
39 saving the target contents. It is guaranteed by the caller to be
40 long enough to save BREAKPOINT_LEN bytes (this is accomplished via
44 default_memory_insert_breakpoint (struct gdbarch
*gdbarch
,
45 struct bp_target_info
*bp_tgt
)
48 const unsigned char *bp
;
51 /* Determine appropriate breakpoint contents and size for this address. */
52 bp
= gdbarch_breakpoint_from_pc
53 (gdbarch
, &bp_tgt
->placed_address
, &bp_tgt
->placed_size
);
55 error (_("Software breakpoints not implemented for this target."));
57 /* Save the memory contents in the shadow_contents buffer and then
58 write the breakpoint instruction. */
59 bp_tgt
->shadow_len
= bp_tgt
->placed_size
;
60 readbuf
= alloca (bp_tgt
->placed_size
);
61 val
= target_read_memory (bp_tgt
->placed_address
, readbuf
,
65 memcpy (bp_tgt
->shadow_contents
, readbuf
, bp_tgt
->placed_size
);
66 val
= target_write_raw_memory (bp_tgt
->placed_address
, bp
,
75 default_memory_remove_breakpoint (struct gdbarch
*gdbarch
,
76 struct bp_target_info
*bp_tgt
)
78 return target_write_raw_memory (bp_tgt
->placed_address
, bp_tgt
->shadow_contents
,
84 memory_insert_breakpoint (struct gdbarch
*gdbarch
,
85 struct bp_target_info
*bp_tgt
)
87 return gdbarch_memory_insert_breakpoint (gdbarch
, bp_tgt
);
91 memory_remove_breakpoint (struct gdbarch
*gdbarch
,
92 struct bp_target_info
*bp_tgt
)
94 return gdbarch_memory_remove_breakpoint (gdbarch
, bp_tgt
);