/* Simulate breakpoints by patching locations in the target system, for GDB.
- Copyright 1990, 1991, 1995 Free Software Foundation, Inc.
- Contributed by Cygnus Support. Written by John Gilmore.
-This file is part of GDB.
+ Copyright (C) 1990-2020 Free Software Foundation, Inc.
-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 2 of the License, or
-(at your option) any later version.
+ Contributed by Cygnus Support. Written by John Gilmore.
-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.
+ This file is part of GDB.
-You should have received a copy of the GNU General Public License
-along with this program; if not, write to the Free Software
-Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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"
+ 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.
-/* 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 "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). */
-/* Use the program counter to determine the contents and size
- of a breakpoint instruction. If no target-dependent macro
- BREAKPOINT_FROM_PC has been defined to implement this function,
- assume that the breakpoint doesn't depend on the PC, and
- use the values of the BIG_BREAKPOINT and LITTLE_BREAKPOINT macros.
- Return a pointer to a string of bytes that encode a breakpoint
- instruction, stores the length of the string to *lenptr,
- and optionally adjust the pc to point to the correct memory location
- for inserting the breakpoint. */
-
-unsigned char *
-memory_breakpoint_from_pc (pcptr, lenptr)
- CORE_ADDR *pcptr;
- int *lenptr;
+int
+default_memory_insert_breakpoint (struct gdbarch *gdbarch,
+ struct bp_target_info *bp_tgt)
{
- /* {BIG_,LITTLE_}BREAKPOINT 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. */
-#ifdef BIG_BREAKPOINT
- if (TARGET_BYTE_ORDER == BIG_ENDIAN)
- {
- static unsigned char big_break_insn[] = BIG_BREAKPOINT;
- *lenptr = sizeof (big_break_insn);
- return big_break_insn;
- }
-#endif
-#ifdef LITTLE_BREAKPOINT
- if (TARGET_BYTE_ORDER != BIG_ENDIAN)
+ 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)
{
- static unsigned char little_break_insn[] = LITTLE_BREAKPOINT;
- *lenptr = sizeof (little_break_insn);
- return little_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);
}
-#endif
-#ifdef BREAKPOINT
- {
- static unsigned char break_insn[] = BREAKPOINT;
- *lenptr = sizeof (break_insn);
- return break_insn;
- }
-#endif
- *lenptr = 0;
- return NULL;
-}
+ return val;
+}
-/* 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. 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 BREAKPOINT_LEN bytes (this
- is accomplished via BREAKPOINT_MAX). */
int
-memory_insert_breakpoint (addr, contents_cache)
- CORE_ADDR addr;
- char *contents_cache;
+default_memory_remove_breakpoint (struct gdbarch *gdbarch,
+ struct bp_target_info *bp_tgt)
{
- int val;
- unsigned char *bp;
int bplen;
- /* Determine appropriate breakpoint contents and size for this address. */
- bp = BREAKPOINT_FROM_PC (&addr, &bplen);
- if (bp == NULL)
- error ("Software breakpoints not implemented for this target.");
+ gdbarch_sw_breakpoint_from_kind (gdbarch, bp_tgt->kind, &bplen);
- /* Save the memory contents. */
- val = target_read_memory (addr, contents_cache, bplen);
+ return target_write_raw_memory (bp_tgt->placed_address, bp_tgt->shadow_contents,
+ bplen);
+}
- /* Write the breakpoint. */
- if (val == 0)
- val = target_write_memory (addr, (char *)bp, bplen);
- return val;
+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_remove_breakpoint (addr, contents_cache)
- CORE_ADDR addr;
- char *contents_cache;
+memory_validate_breakpoint (struct gdbarch *gdbarch,
+ struct bp_target_info *bp_tgt)
{
- unsigned char *bp;
+ 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);
- /* Determine appropriate breakpoint contents and size for this address. */
- bp = BREAKPOINT_FROM_PC (&addr, &bplen);
if (bp == NULL)
- error ("Software breakpoints not implemented for this target.");
+ 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);
- return target_write_memory (addr, contents_cache, 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