X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Fmem-break.c;h=8e2debfba386e3944d90c3380934b95f43cd8431;hb=98bbb1b86180324b278842d8d73c79cb5d76d349;hp=da400e041c30eb364636b69d7a5ad6e4dc05f241;hpb=c5aa993b1f4add48fbdc6cc3117059f616e49875;p=deliverable%2Fbinutils-gdb.git diff --git a/gdb/mem-break.c b/gdb/mem-break.c index da400e041c..8e2debfba3 100644 --- a/gdb/mem-break.c +++ b/gdb/mem-break.c @@ -1,12 +1,14 @@ /* Simulate breakpoints by patching locations in the target system, for GDB. - Copyright 1990, 1991, 1995 Free Software Foundation, Inc. + + Copyright (C) 1990-2017 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, @@ -15,111 +17,111 @@ 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 . */ #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" +/* 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); }