X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Fmem-break.c;h=a251aa4337251c45687cba366b06fbc42b4082b5;hb=963eeee42ab212c2512b829143986fd3bb2fd93b;hp=eebe7e251f1fe553e5a6bcc6c71db2fed9ffd7c8;hpb=bd5635a1e2b38ee8432fcdaa6456079191375277;p=deliverable%2Fbinutils-gdb.git

diff --git a/gdb/mem-break.c b/gdb/mem-break.c
index eebe7e251f..a251aa4337 100644
--- a/gdb/mem-break.c
+++ b/gdb/mem-break.c
@@ -1,178 +1,129 @@
-/* Simulate breakpoints by patching locations in the target system.
-   Copyright (C) 1990 Free Software Foundation, Inc.
+/* Simulate breakpoints by patching locations in the target system, for GDB.
 
-This file is part of GDB.
+   Copyright (C) 1990-2020 Free Software Foundation, Inc.
 
-GDB 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 1, or (at your option)
-any later version.
+   Contributed by Cygnus Support.  Written by John Gilmore.
 
-GDB 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 GDB; see the file COPYING.  If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, 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"
-#include "param.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.
 
-#ifdef BREAKPOINT
-/* 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 <stdio.h>
+#include "defs.h"
+#include "symtab.h"
 #include "breakpoint.h"
 #include "inferior.h"
 #include "target.h"
+#include "gdbarch.h"
 
-/* This 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.  */
-
-static char break_insn[] = BREAKPOINT;
-
-/* This is only to check that BREAKPOINT fits in BREAKPOINT_MAX bytes.  */
-
-static char check_break_insn_size[BREAKPOINT_MAX] = BREAKPOINT;
-
-/* Insert a breakpoint on machines 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 sizeof BREAKPOINT bytes.
-   FIXME: This size is target_arch dependent and should be available in
-   the target_arch transfer vector, if we ever have one...  */
+/* 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
-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)
 {
+  CORE_ADDR addr = bp_tgt->placed_address;
+  const unsigned char *bp;
+  gdb_byte *readbuf;
+  int bplen;
   int val;
 
-  val = target_read_memory (addr, contents_cache, sizeof break_insn);
+  /* 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)
-    val = target_write_memory (addr, break_insn, sizeof 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);
+    }
 
   return val;
 }
 
 
 int
-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)
 {
-  return target_write_memory (addr, contents_cache, sizeof break_insn);
-}
+  int bplen;
 
+  gdbarch_sw_breakpoint_from_kind (gdbarch, bp_tgt->kind, &bplen);
+
+  return target_write_raw_memory (bp_tgt->placed_address, bp_tgt->shadow_contents,
+				  bplen);
+}
 
-#if 0
-/* This should move back into breakpoint.c, sad to say.   Encapsulate
-    sizeof (BREAKPOINT) by export it as an int from mem-break.c.  */
 
-/* Like target_read_memory() but if breakpoints are inserted, return
-   the shadow contents instead of the breakpoints themselves.  */
 int
-read_memory_nobpt (memaddr, myaddr, len)
-     CORE_ADDR memaddr;
-     char *myaddr;
-     unsigned len;
+memory_insert_breakpoint (struct target_ops *ops, struct gdbarch *gdbarch,
+			  struct bp_target_info *bp_tgt)
 {
-  int status;
-  struct breakpoint *b;
-  ALL_BREAKPOINTS (b)
-    {
-      if (b->address == NULL || !b->inserted)
-	continue;
-      else if (b->address + sizeof (break_insn) <= memaddr)
-	/* The breakpoint is entirely before the chunk of memory
-	   we are reading.  */
-	continue;
-      else if (b->address >= memaddr + len)
-	/* The breakpoint is entirely after the chunk of memory we
-	   are reading.  */
-	continue;
-      else
-	{
-	  /* Copy the breakpoint from the shadow contents, and recurse
-	     for the things before and after.  */
-	  
-	  /* Addresses and length of the part of the breakpoint that
-	     we need to copy.  */
-	  CORE_ADDR membpt = b->address;
-	  unsigned int bptlen = sizeof (break_insn);
-	  /* Offset within shadow_contents.  */
-	  int bptoffset = 0;
-	  
-	  if (membpt < memaddr)
-	    {
-	      /* Only copy the second part of the breakpoint.  */
-	      bptlen -= memaddr - membpt;
-	      bptoffset = memaddr - membpt;
-	      membpt = memaddr;
-	    }
-
-	  if (membpt + bptlen > memaddr + len)
-	    {
-	      /* Only copy the first part of the breakpoint.  */
-	      bptlen -= (membpt + bptlen) - (memaddr + len);
-	    }
-
-	  bcopy (b->shadow_contents + bptoffset,
-		 myaddr + membpt - memaddr, bptlen);
-
-	  if (membpt > memaddr)
-	    {
-	      /* Copy the section of memory before the breakpoint.  */
-	      status = read_memory_nobpt (memaddr, myaddr, membpt - memaddr);
-	      if (status != 0)
-		return status;
-	    }
-
-	  if (membpt + bptlen < memaddr + len)
-	    {
-	      /* Copy the section of memory after the breakpoint.  */
-	      status = read_memory_nobpt
-		(membpt + bptlen,
-		 myaddr + membpt + bptlen - memaddr,
-		 memaddr + len - (membpt + bptlen));
-	      if (status != 0)
-		return status;
-	    }
-	  return 0;
-	}
-    }
-  /* Nothing overlaps.  Just call read_memory_noerr.  */
-  return target_read_memory (memaddr, myaddr, len);
+  return gdbarch_memory_insert_breakpoint (gdbarch, bp_tgt);
 }
-#endif /* 0 */
-
-#else  /* BREAKPOINT */
-
-char nogo[] = "Breakpoints not implemented for this target.";
 
 int
-memory_insert_breakpoint (addr, contents_cache)
-     CORE_ADDR addr;
-     char *contents_cache;
+memory_remove_breakpoint (struct target_ops *ops, struct gdbarch *gdbarch,
+			  struct bp_target_info *bp_tgt,
+			  enum remove_bp_reason reason)
 {
-  error (nogo);
-  return 0;	/* lint */
+  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)
 {
-  error (nogo);
-  return 0;	/* lint */
-}
+  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;
 
-#endif /* BREAKPOINT */
+  /* 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);
+}