-/* Simulate breakpoints by patching locations in the target system.
- Copyright (C) 1990 Free Software Foundation, Inc.
+/* Simulate breakpoints by patching locations in the target system, for GDB.
-This file is part of GDB.
+ Copyright (C) 1990-2020 Free Software Foundation, Inc.
-GDB 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 1, or (at your option)
-any later version.
+ Contributed by Cygnus Support. Written by John Gilmore.
-GDB 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.
+ This file is part of GDB.
-You should have received a copy of the GNU General Public License
-along with GDB; see the file COPYING. If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
+ 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.
-#include "defs.h"
-#include "param.h"
+ 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.
-#ifdef BREAKPOINT
-/* This file is only useful if BREAKPOINT is set. If not, we punt. */
+ 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 <stdio.h>
+#include "defs.h"
+#include "symtab.h"
#include "breakpoint.h"
#include "inferior.h"
#include "target.h"
+#include "gdbarch.h"
-/* This is the sequence of bytes we insert for a breakpoint. On some
- machines, breakpoints are handled by the target environment and we
- don't have to worry about them here. */
-
-static char break_insn[] = BREAKPOINT;
-
-/* This is only to check that BREAKPOINT fits in BREAKPOINT_MAX bytes. */
-
-static char check_break_insn_size[BREAKPOINT_MAX] = BREAKPOINT;
-
-/* Insert a breakpoint on machines 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. ADDR is the target
- location in the target machine. CONTENTS_CACHE is a pointer to
- memory allocated for saving the target contents. It is guaranteed
- by the caller to be long enough to save sizeof BREAKPOINT bytes.
- FIXME: This size is target_arch dependent and should be available in
- the target_arch transfer vector, if we ever have one... */
+/* 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
-memory_insert_breakpoint (addr, contents_cache)
- CORE_ADDR addr;
- char *contents_cache;
+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;
- val = target_read_memory (addr, contents_cache, sizeof break_insn);
+ /* 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)
- val = target_write_memory (addr, break_insn, sizeof break_insn);
+ {
+ /* 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
-memory_remove_breakpoint (addr, contents_cache)
- CORE_ADDR addr;
- char *contents_cache;
+default_memory_remove_breakpoint (struct gdbarch *gdbarch,
+ struct bp_target_info *bp_tgt)
{
- return target_write_memory (addr, contents_cache, sizeof break_insn);
-}
+ 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);
+}
-#if 0
-/* This should move back into breakpoint.c, sad to say. Encapsulate
- sizeof (BREAKPOINT) by export it as an int from mem-break.c. */
-/* Like target_read_memory() but if breakpoints are inserted, return
- the shadow contents instead of the breakpoints themselves. */
int
-read_memory_nobpt (memaddr, myaddr, len)
- CORE_ADDR memaddr;
- char *myaddr;
- unsigned len;
+memory_insert_breakpoint (struct target_ops *ops, struct gdbarch *gdbarch,
+ struct bp_target_info *bp_tgt)
{
- int status;
- struct breakpoint *b;
- ALL_BREAKPOINTS (b)
- {
- if (b->address == NULL || !b->inserted)
- continue;
- else if (b->address + sizeof (break_insn) <= memaddr)
- /* The breakpoint is entirely before the chunk of memory
- we are reading. */
- continue;
- else if (b->address >= memaddr + len)
- /* The breakpoint is entirely after the chunk of memory we
- are reading. */
- continue;
- else
- {
- /* Copy the breakpoint from the shadow contents, and recurse
- for the things before and after. */
-
- /* Addresses and length of the part of the breakpoint that
- we need to copy. */
- CORE_ADDR membpt = b->address;
- unsigned int bptlen = sizeof (break_insn);
- /* Offset within shadow_contents. */
- int bptoffset = 0;
-
- if (membpt < memaddr)
- {
- /* Only copy the second part of the breakpoint. */
- bptlen -= memaddr - membpt;
- bptoffset = memaddr - membpt;
- membpt = memaddr;
- }
-
- if (membpt + bptlen > memaddr + len)
- {
- /* Only copy the first part of the breakpoint. */
- bptlen -= (membpt + bptlen) - (memaddr + len);
- }
-
- bcopy (b->shadow_contents + bptoffset,
- myaddr + membpt - memaddr, bptlen);
-
- if (membpt > memaddr)
- {
- /* Copy the section of memory before the breakpoint. */
- status = read_memory_nobpt (memaddr, myaddr, membpt - memaddr);
- if (status != 0)
- return status;
- }
-
- if (membpt + bptlen < memaddr + len)
- {
- /* Copy the section of memory after the breakpoint. */
- status = read_memory_nobpt
- (membpt + bptlen,
- myaddr + membpt + bptlen - memaddr,
- memaddr + len - (membpt + bptlen));
- if (status != 0)
- return status;
- }
- return 0;
- }
- }
- /* Nothing overlaps. Just call read_memory_noerr. */
- return target_read_memory (memaddr, myaddr, len);
+ return gdbarch_memory_insert_breakpoint (gdbarch, bp_tgt);
}
-#endif /* 0 */
-
-#else /* BREAKPOINT */
-
-char nogo[] = "Breakpoints not implemented for this target.";
int
-memory_insert_breakpoint (addr, contents_cache)
- CORE_ADDR addr;
- char *contents_cache;
+memory_remove_breakpoint (struct target_ops *ops, struct gdbarch *gdbarch,
+ struct bp_target_info *bp_tgt,
+ enum remove_bp_reason reason)
{
- error (nogo);
- return 0; /* lint */
+ return gdbarch_memory_remove_breakpoint (gdbarch, bp_tgt);
}
int
-memory_remove_breakpoint (addr, contents_cache)
- CORE_ADDR addr;
- char *contents_cache;
+memory_validate_breakpoint (struct gdbarch *gdbarch,
+ struct bp_target_info *bp_tgt)
{
- error (nogo);
- return 0; /* lint */
-}
+ 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;
-#endif /* BREAKPOINT */
+ /* 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);
+}
projects / deliverable / binutils-gdb.git / blobdiff