/* Simulate breakpoints by patching locations in the target system, for GDB.
- Copyright 1990, 1991, 1995 Free Software Foundation, Inc.
+
+ Copyright (C) 1990-2020 Free Software Foundation, Inc.
+
Contributed by Cygnus Support. Written by John Gilmore.
This file is part of GDB.
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
+ the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
GNU General Public License for more details.
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. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
-
-/* This file is only useful if BREAKPOINT is set. If not, we punt. */
-
#include "symtab.h"
#include "breakpoint.h"
#include "inferior.h"
#include "target.h"
+#include "gdbarch.h"
-
-/* 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;
-{
- /* {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)
- {
- static unsigned char little_break_insn[] = LITTLE_BREAKPOINT;
- *lenptr = sizeof (little_break_insn);
- return little_break_insn;
- }
-#endif
-#ifdef BREAKPOINT
- {
- static unsigned char break_insn[] = BREAKPOINT;
- *lenptr = sizeof (break_insn);
- return break_insn;
- }
-#endif
- *lenptr = 0;
- return NULL;
-}
-
-
-/* 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). */
+/* 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
-default_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)
{
- int val;
- unsigned char *bp;
+ 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 = BREAKPOINT_FROM_PC (&addr, &bplen);
- if (bp == NULL)
- error ("Software breakpoints not implemented for this target.");
+ bp = gdbarch_sw_breakpoint_from_kind (gdbarch, bp_tgt->kind, &bplen);
- /* Save the memory contents. */
- val = target_read_memory (addr, contents_cache, bplen);
-
- /* Write the breakpoint. */
+ /* 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, (char *) bp, bplen);
+ {
+ /* 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
-default_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)
{
- 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);
- return target_write_memory (addr, contents_cache, bplen);
+ return target_write_raw_memory (bp_tgt->placed_address, bp_tgt->shadow_contents,
+ bplen);
}
int
-memory_insert_breakpoint (addr, contents_cache)
- CORE_ADDR addr;
- char *contents_cache;
+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 MEMORY_INSERT_BREAKPOINT(addr, contents_cache);
+ 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)
{
- return MEMORY_REMOVE_BREAKPOINT(addr, contents_cache);
+ 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;
+
+ /* 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