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179 lines
4.9 KiB
C
179 lines
4.9 KiB
C
/* Simulate breakpoints by patching locations in the target system.
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Copyright (C) 1990 Free Software Foundation, Inc.
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This file is part of GDB.
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GDB is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 1, or (at your option)
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any later version.
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GDB is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GDB; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include "defs.h"
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#include "param.h"
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#ifdef BREAKPOINT
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/* This file is only useful if BREAKPOINT is set. If not, we punt. */
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#include <stdio.h>
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#include "breakpoint.h"
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#include "inferior.h"
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#include "target.h"
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/* This is the sequence of bytes we insert for a breakpoint. On some
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machines, breakpoints are handled by the target environment and we
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don't have to worry about them here. */
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static char break_insn[] = BREAKPOINT;
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/* This is only to check that BREAKPOINT fits in BREAKPOINT_MAX bytes. */
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static char check_break_insn_size[BREAKPOINT_MAX] = BREAKPOINT;
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/* Insert a breakpoint on machines that don't have any better breakpoint
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support. We read the contents of the target location and stash it,
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then overwrite it with a breakpoint instruction. ADDR is the target
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location in the target machine. CONTENTS_CACHE is a pointer to
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memory allocated for saving the target contents. It is guaranteed
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by the caller to be long enough to save sizeof BREAKPOINT bytes.
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FIXME: This size is target_arch dependent and should be available in
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the target_arch transfer vector, if we ever have one... */
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int
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memory_insert_breakpoint (addr, contents_cache)
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CORE_ADDR addr;
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char *contents_cache;
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{
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int val;
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val = target_read_memory (addr, contents_cache, sizeof break_insn);
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if (val == 0)
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val = target_write_memory (addr, break_insn, sizeof break_insn);
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return val;
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}
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int
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memory_remove_breakpoint (addr, contents_cache)
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CORE_ADDR addr;
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char *contents_cache;
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{
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return target_write_memory (addr, contents_cache, sizeof break_insn);
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}
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#if 0
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/* This should move back into breakpoint.c, sad to say. Encapsulate
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sizeof (BREAKPOINT) by export it as an int from mem-break.c. */
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/* Like target_read_memory() but if breakpoints are inserted, return
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the shadow contents instead of the breakpoints themselves. */
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int
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read_memory_nobpt (memaddr, myaddr, len)
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CORE_ADDR memaddr;
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char *myaddr;
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unsigned len;
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{
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int status;
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struct breakpoint *b;
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ALL_BREAKPOINTS (b)
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{
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if (b->address == NULL || !b->inserted)
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continue;
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else if (b->address + sizeof (break_insn) <= memaddr)
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/* The breakpoint is entirely before the chunk of memory
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we are reading. */
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continue;
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else if (b->address >= memaddr + len)
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/* The breakpoint is entirely after the chunk of memory we
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are reading. */
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continue;
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else
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{
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/* Copy the breakpoint from the shadow contents, and recurse
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for the things before and after. */
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/* Addresses and length of the part of the breakpoint that
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we need to copy. */
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CORE_ADDR membpt = b->address;
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unsigned int bptlen = sizeof (break_insn);
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/* Offset within shadow_contents. */
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int bptoffset = 0;
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if (membpt < memaddr)
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{
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/* Only copy the second part of the breakpoint. */
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bptlen -= memaddr - membpt;
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bptoffset = memaddr - membpt;
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membpt = memaddr;
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}
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if (membpt + bptlen > memaddr + len)
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{
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/* Only copy the first part of the breakpoint. */
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bptlen -= (membpt + bptlen) - (memaddr + len);
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}
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bcopy (b->shadow_contents + bptoffset,
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myaddr + membpt - memaddr, bptlen);
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if (membpt > memaddr)
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{
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/* Copy the section of memory before the breakpoint. */
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status = read_memory_nobpt (memaddr, myaddr, membpt - memaddr);
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if (status != 0)
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return status;
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}
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if (membpt + bptlen < memaddr + len)
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{
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/* Copy the section of memory after the breakpoint. */
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status = read_memory_nobpt
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(membpt + bptlen,
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myaddr + membpt + bptlen - memaddr,
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memaddr + len - (membpt + bptlen));
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if (status != 0)
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return status;
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}
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return 0;
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}
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}
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/* Nothing overlaps. Just call read_memory_noerr. */
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return target_read_memory (memaddr, myaddr, len);
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}
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#endif /* 0 */
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#else /* BREAKPOINT */
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char nogo[] = "Breakpoints not implemented for this target.";
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int
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memory_insert_breakpoint (addr, contents_cache)
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CORE_ADDR addr;
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char *contents_cache;
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{
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error (nogo);
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return 0; /* lint */
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}
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int
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memory_remove_breakpoint (addr, contents_cache)
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CORE_ADDR addr;
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char *contents_cache;
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{
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error (nogo);
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return 0; /* lint */
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}
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#endif /* BREAKPOINT */
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