1 /* Simulate breakpoints by patching locations in the target system, for GDB. 2 3 Copyright (C) 1990-1993, 1995, 1997-2000, 2002, 2007-2012 Free 4 Software Foundation, Inc. 5 6 Contributed by Cygnus Support. Written by John Gilmore. 7 8 This file is part of GDB. 9 10 This program is free software; you can redistribute it and/or modify 11 it under the terms of the GNU General Public License as published by 12 the Free Software Foundation; either version 3 of the License, or 13 (at your option) any later version. 14 15 This program is distributed in the hope that it will be useful, 16 but WITHOUT ANY WARRANTY; without even the implied warranty of 17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 GNU General Public License for more details. 19 20 You should have received a copy of the GNU General Public License 21 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 22 23 #include "defs.h" 24 25 /* This file is only useful if BREAKPOINT_FROM_PC is set. If not, we 26 punt. */ 27 28 #include "symtab.h" 29 #include "breakpoint.h" 30 #include "inferior.h" 31 #include "target.h" 32 33 34 /* Insert a breakpoint on targets that don't have any better 35 breakpoint support. We read the contents of the target location 36 and stash it, then overwrite it with a breakpoint instruction. 37 BP_TGT->placed_address is the target location in the target 38 machine. BP_TGT->shadow_contents is some memory allocated for 39 saving the target contents. It is guaranteed by the caller to be 40 long enough to save BREAKPOINT_LEN bytes (this is accomplished via 41 BREAKPOINT_MAX). */ 42 43 int 44 default_memory_insert_breakpoint (struct gdbarch *gdbarch, 45 struct bp_target_info *bp_tgt) 46 { 47 int val; 48 const unsigned char *bp; 49 50 /* Determine appropriate breakpoint contents and size for this address. */ 51 bp = gdbarch_breakpoint_from_pc 52 (gdbarch, &bp_tgt->placed_address, &bp_tgt->placed_size); 53 if (bp == NULL) 54 error (_("Software breakpoints not implemented for this target.")); 55 56 /* Save the memory contents. */ 57 bp_tgt->shadow_len = bp_tgt->placed_size; 58 val = target_read_memory (bp_tgt->placed_address, bp_tgt->shadow_contents, 59 bp_tgt->placed_size); 60 61 /* Write the breakpoint. */ 62 if (val == 0) 63 val = target_write_raw_memory (bp_tgt->placed_address, bp, 64 bp_tgt->placed_size); 65 66 return val; 67 } 68 69 70 int 71 default_memory_remove_breakpoint (struct gdbarch *gdbarch, 72 struct bp_target_info *bp_tgt) 73 { 74 return target_write_raw_memory (bp_tgt->placed_address, bp_tgt->shadow_contents, 75 bp_tgt->placed_size); 76 } 77 78 79 int 80 memory_insert_breakpoint (struct gdbarch *gdbarch, 81 struct bp_target_info *bp_tgt) 82 { 83 return gdbarch_memory_insert_breakpoint (gdbarch, bp_tgt); 84 } 85 86 int 87 memory_remove_breakpoint (struct gdbarch *gdbarch, 88 struct bp_target_info *bp_tgt) 89 { 90 return gdbarch_memory_remove_breakpoint (gdbarch, bp_tgt); 91 } 92