Re: [RFA] i386/amd64 h/w watchpoints in gdbserver

[Doug Evans <dje@google.com>]

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On Sat, Jun 20, 2009 at 4:55 PM, Pedro Alves<pedro@codesourcery.com> wrote:
> On Tuesday 02 June 2009 16:36:05, Doug Evans wrote:
>
>> RCS file: i386-low.c
>> diff -N i386-low.c
>> --- /dev/null   1 Jan 1970 00:00:00 -0000
>> +++ i386-low.c  1 Jun 2009 22:02:43 -0000
>> @@ -0,0 +1,660 @@
>
>
>> +/* Support for 8-byte wide hw watchpoints.  */
>> +#ifndef TARGET_HAS_DR_LEN_8
>> +#define TARGET_HAS_DR_LEN_8 (sizeof (long) == 8)
>
> Note: this will be trouble for Win64 (sizeof(long) == 4, sizeof (ptr) == 8)

changed to sizeof (void *)

>> +/* Set in DR7 the RW and LEN fields for the I'th debug register.  */
>> +#define I386_DR_SET_RW_LEN(state, i,rwlen) \
>> +  do { \
>> +    (state)->dr_control_mirror &= \
>> +      ~(0x0f << (DR_CONTROL_SHIFT+DR_CONTROL_SIZE*(i))); \
>> +    (state)->dr_control_mirror |= \
>> +      ((rwlen) << (DR_CONTROL_SHIFT+DR_CONTROL_SIZE*(i))); \
>> +  } while (0)
>
> Spaces around operators missing, here and several other places.
> I realise this is copied from GDB, but IWBN to fix this while we
> go.  Feel free to fix it on GDB as well, as obvious.

patch updated.

>> +/* Whether or not to print the mirrored debug registers.  */
>> +static int maint_show_dr = 0;
>
> I see nowhere where this can be set.  There are a few references to
> GDB's main show-debug-regs command left behind.  Could this be set with
> a command line option and/or monitor command perhaps?

It was useful during debugging, I just hardcoded it to 1.
As for how to really enable set it, I wasn't sure.
I added a monitor command.

>
>> +
>> +/* Types of operations supported by i386_handle_nonaligned_watchpoint.  */
>> +typedef enum { WP_INSERT, WP_REMOVE, WP_COUNT } i386_wp_op_t;
>> +
>> +/* Internal functions.  */
>> +
>> +/* Return the value of a 4-bit field for DR7 suitable for watching a
>> +   region of LEN bytes for accesses of type TYPE.  LEN is assumed to
>> +   have the value of 1, 2, or 4.  */
>> +static unsigned i386_length_and_rw_bits (int len, enum target_hw_bp_type type);
>> +
>> +/* Insert a watchpoint at address ADDR, which is assumed to be aligned
>> +   according to the length of the region to watch.  LEN_RW_BITS is the
>> +   value of the bit-field from DR7 which describes the length and
>> +   access type of the region to be watched by this watchpoint.  Return
>> +   0 on success, -1 on failure.  */
>> +static int i386_insert_aligned_watchpoint (struct i386_debug_reg_state *state,
>> +                                          CORE_ADDR addr,
>> +                                          unsigned len_rw_bits);
>> +
>> +/* Remove a watchpoint at address ADDR, which is assumed to be aligned
>> +   according to the length of the region to watch.  LEN_RW_BITS is the
>> +   value of the bits from DR7 which describes the length and access
>> +   type of the region watched by this watchpoint.  Return 0 on
>> +   success, -1 on failure.  */
>> +static int i386_remove_aligned_watchpoint (struct i386_debug_reg_state *state,
>> +                                          CORE_ADDR addr,
>> +                                          unsigned len_rw_bits);
>> +
>> +/* Insert or remove a (possibly non-aligned) watchpoint, or count the
>> +   number of debug registers required to watch a region at address
>> +   ADDR whose length is LEN for accesses of type TYPE.  Return 0 on
>> +   successful insertion or removal, a positive number when queried
>> +   about the number of registers, or -1 on failure.  If WHAT is not a
>> +   valid value, bombs through fatal.  */
>> +static int i386_handle_nonaligned_watchpoint (struct i386_debug_reg_state *state,
>> +                                             i386_wp_op_t what,
>> +                                             CORE_ADDR addr, int len,
>> +                                             enum target_hw_bp_type type);
>
> I don't think none of these forward declarations is needed?

ok
[once upon a time, they were ok. the new rules haven't been locked in
memory yet]

>> +
>> +/* Implementation.  */
>> +
>> +/* Clear the reference counts and forget everything we knew about the
>> +   debug registers.  */
>> +
>> +void
>> +i386_low_cleanup_dregs (struct i386_debug_reg_state *state)
>> +{
>> +  int i;
>> +
>> +  ALL_DEBUG_REGISTERS(i)
>> +    {
>> +      state->dr_mirror[i] = 0;
>> +      state->dr_ref_count[i] = 0;
>> +    }
>> +  state->dr_control_mirror = 0;
>> +  state->dr_status_mirror  = 0;
>> +}
>
> This isn't called anywhere?

Ah.  'tis now.

>> +
>> +/* Print the values of the mirrored debug registers.  This is called
>> +   when maint_show_dr is non-zero.
>
>> To set that up, type "maint
>> +   show-debug-regs" at GDB's prompt.  */
>
> Nope, this is a lie.

fixed.

>> +
>> +static void
>> +i386_show_dr (struct i386_debug_reg_state *state,
>> +             const char *func, CORE_ADDR addr,
>> +             int len, enum target_hw_bp_type type)
>> +{
>> +  int i;
>> +
>> +  printf (func);
>> +  if (addr || len)
>> +    printf (" (addr=%lx, len=%d, type=%s)",
>> +                      (unsigned long) addr, len,
>> +                      type == hw_write ? "data-write"
>> +                      : (type == hw_read ? "data-read"
>> +                         : (type == hw_access ? "data-read/write"
>> +                            : (type == hw_execute ? "instruction-execute"
>> +                               /* FIXME: if/when I/O read/write
>> +                                  watchpoints are supported, add them
>> +                                  here.  */
>> +                               : "??unknown??"))));
>> +  printf (":\n");
>> +  printf ("\tCONTROL (DR7): %08x          STATUS (DR6): %08x\n",
>> +                    state->dr_control_mirror, state->dr_status_mirror);
>> +  ALL_DEBUG_REGISTERS (i)
>> +    {
>> +      printf ("\
>> +\tDR%d: addr=0x%s, ref.count=%d  DR%d: addr=0x%s, ref.count=%d\n",
>> +                        i, paddr (state->dr_mirror[i]), state->dr_ref_count[i],
>> +                        i+1, paddr (state->dr_mirror[i+1]), state->dr_ref_count[i+1]);
>> +      i++;
>> +    }
>> +}
>
> These should not go to stdout.  GDB should be fixed too to make these go to
> gdb_stdlog.

changed to stderr

>> +
>> +static int
>> +Z_packet_to_hw_type (char type)
>> +{
>> +  switch (type)
>> +    {
>> +    case Z_PACKET_WRITE_WP:  return hw_write;
>> +    case Z_PACKET_READ_WP:   return hw_read;
>> +    case Z_PACKET_ACCESS_WP: return hw_access;
>
> Please don't vertically align.  Stick to the standards and put
> those return statements in their own line.

k.

>> +    default:
>> +      error ("Z_packet_to_hw_type: bad watchpoint type %c", type);
>> +    }
>> +}
>> +
>> +/* Insert a watchpoint to watch a memory region which starts at
>> +   address ADDR and whose length is LEN bytes.  Watch memory accesses
>> +   of the type TYPE_FROM_PACKET.  Return 0 on success, -1 on failure.  */
>> +
>> +int
>> +i386_low_insert_watchpoint (struct i386_debug_reg_state *state,
>> +                           char type_from_packet, CORE_ADDR addr, int len)
>> +{
>> +  int retval;
>> +  int type = Z_packet_to_hw_type (type_from_packet);
>> +
>> +  if (((len != 1 && len !=2 && len !=4) && !(TARGET_HAS_DR_LEN_8 && len == 8))
>
> More examples of missing space around operators coming from GDB.

patch updated

>> +
>> +/* If the inferior has some watchpoint that triggered, set the
>> +   address associated with that watchpoint and return non-zero.
>> +   Otherwise, return zero.  */
>> +
>> +CORE_ADDR
>> +i386_low_stopped_data_address (struct i386_debug_reg_state *state)
>> +{
>> +  CORE_ADDR addr = 0;
>> +  int i;
>> +
>> +  /* Get dr_status_mirror for use by I386_DR_WATCH_HIT.  */
>> +  i386_dr_low_get_status (state);
>> +
>> +  ALL_DEBUG_REGISTERS(i)
>> +    {
>> +      if (I386_DR_WATCH_HIT (state, i)
>> +         /* This second condition makes sure DRi is set up for a data
>> +            watchpoint, not a hardware breakpoint.  The reason is
>> +            that GDB doesn't call the target_stopped_data_address
>> +            method except for data watchpoints.  In other words, I'm
>> +            being paranoiac.  */
>> +         && I386_DR_GET_RW_LEN (state, i) != 0)
>> +       {
>> +         addr = state->dr_mirror[i];
>> +         if (maint_show_dr)
>> +           i386_show_dr (state, "watchpoint_hit", addr, -1, hw_write);
>> +       }
>> +    }
>> +
>> +  if (maint_show_dr && addr == 0)
>> +    i386_show_dr (state, "stopped_data_addr", 0, 0, hw_write);
>> +
>
>> +  /* NOTE: gdb version checks rc != 0 here.  */
>> +  return addr;
>> +}
>
> Indeed.  GDB's interface was fixed to allow watchpoints at 0.  I
> don't think that matters for any gdbserver target, but it would
> be nice to fix the interface anyway...

patch updated

>> +
>> +int
>> +i386_low_stopped_by_watchpoint (struct i386_debug_reg_state *state)
>> +{
>> +  CORE_ADDR addr = 0;
>> +  /* NOTE: gdb version passes boolean found/not-found result from
>> +     i386_stopped_data_address.  */
>> +  addr = i386_low_stopped_data_address (state);
>> +  return (addr != 0);
>> +}
>
> Same as above.  You've probably thought about that too...
>
>> +
>> +/* Support for h/w breakpoints.
>> +   This support is not currently used, kept for reference.  */
>
> Any reason for not using this currently?  If there's a good reason,
> than let's drop it.  But I'd prefer to have it working.  :-)

deleted.

>> Index: utils.c
>> ===================================================================
>
> +char *
> +paddr (CORE_ADDR addr)
>
> This isn't documented in neither server.h or here?

Just "going with the flow".

> +{
> +  char *str = get_cell ();
> +  xsnprintf (str, CELLSIZE, "%lx", (long) addr);
>
>                                     ^^^^
>
> Note: this will be wrong on Win64...  BTW, Ulrich
> was removing several of these functions from GDB
> in the removing-current_gdbarch series.  Will this one
> stay?  Might be worth it to use the one that is going
> to stay in GDB.

I think a higher order bit is that gdb and gdbserver cannot share
code.  Bringing over all the smarts to handle all the different
portability issues is painful/depressing.  I went with something
simple that works for now.
IWBN if this kind of thing were in, say, libiberty and tools could just use it.

>
> +  return str;
> +}
>
>
>
>> Index: linux-low.c
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/gdbserver/linux-low.c,v
>> retrieving revision 1.105
>> diff -u -p -r1.105 linux-low.c
>> --- linux-low.c 24 May 2009 17:44:19 -0000      1.105
>> +++ linux-low.c 1 Jun 2009 22:02:43 -0000
>> @@ -224,6 +224,7 @@ delete_lwp (struct lwp_info *lwp)
>>  {
>>    remove_thread (get_lwp_thread (lwp));
>>    remove_inferior (&all_lwps, &lwp->head);
>> +  free (lwp->arch_private);
>>    free (lwp);
>>  }
>>
>> @@ -242,6 +243,9 @@ linux_add_process (int pid, int attached
>>    proc = add_process (pid, attached);
>>    proc->private = xcalloc (1, sizeof (*proc->private));
>>
>> +  if (the_low_target.new_process != NULL)
>> +    proc->private->arch_private = the_low_target.new_process (pid, attached);
>
> ( Wouldn't the interface be a bit cleaner if you
> passed the 'proc' pointer down to new_process, and have the
> callback manage arch_private field itself?  As is, your passing
> some useless parameters down.  If they end up being needed,
> it is likely that an extra look up on pid would be needed to
> get at the structure.  This would also migrate better to a
> per-process data mechanism similar to gdb's objfile_data, if
> need be. )

args deleted.

>> Index: linux-low.h
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/gdbserver/linux-low.h,v
>> retrieving revision 1.30
>> diff -u -p -r1.30 linux-low.h
>> --- linux-low.h 12 May 2009 22:25:00 -0000      1.30
>> +++ linux-low.h 1 Jun 2009 22:02:43 -0000
>> @@ -56,8 +56,13 @@ struct process_info_private
>>
>>    /* Connection to the libthread_db library.  */
>>    td_thragent_t *thread_agent;
>> +
>> +  /* Target-specific additions.  */
>
> Warning: "Target" overload.  We need to get into the habit
> of not doing this --- it makes refering to these things quite
> ambiguous.  Call it "arch" or something else.  There are other
> similar cases.

I dunno.   there's "the_low_target" in linux-low.h
Perhaps we can migrate away but I don't see the above "infraction" as
being critical.

>>  #define pid_of(proc) ptid_get_pid ((proc)->head.id)
>>  #define lwpid_of(proc) ptid_get_lwp ((proc)->head.id)
>> +#define PIDGET(ptid) ptid_get_pid (ptid)
>> +#define TIDGET(ptid) ptid_get_lwp (ptid)
>
> Why do we need extra ways to do the same thing?  Let's not
> copy GDB's bad habits and legacy code.

k.

>> --- linux-x86-low.c     13 May 2009 19:11:04 -0000      1.2
>> +++ linux-x86-low.c     1 Jun 2009 22:02:43 -0000
>
>> +static unsigned long
>> +x86_linux_dr_get (ptid_t ptid, int regnum)
>> +{
>> +  int tid;
>> +  unsigned long value;
>> +
>> +  tid = TIDGET (ptid);
>> +  if (tid == 0)
>> +    tid = PIDGET (ptid);
>
> The tid == 0 case is dead code coming from GDB, isn't it?
> Likewise in other places.

Perhaps.  There's similar code in linux-low.c:same_lwp.
== 0 code deleted.

>> +
>> +  errno = 0;
>> +  value = ptrace (PTRACE_PEEKUSER, tid,
>> +                 offsetof (struct user, u_debugreg[regnum]), 0);
>> +  if (errno != 0)
>> +    error ("Couldn't read debug register");
>> +
>> +  return value;
>> +}
>> +
>
>> +/* Update the inferior's debug register REGNUM from STATE.  */
>> +
>> +void
>> +i386_dr_low_set_addr (const struct i386_debug_reg_state *state, int regnum)
>> +{
>> +  struct inferior_list_entry *lp;
>> +  CORE_ADDR addr;
>> +
>> +  if (! (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR))
>> +    fatal ("Invalid debug register %d", regnum);
>> +
>> +  addr = state->dr_mirror[regnum];
>> +
>> +  /* ??? Will need tweaking for multi-process.  */
>
> Indeed.  Why not just set the debug_registers_changed in lwps
> of the current process?

Are there any existing examples of this?
I would have done that had process_info contained the list of its
threads (it would have been trivially straightforward).

>> +  for (lp = all_lwps.head; lp; lp = lp->next)
>> +    {
>> +      struct lwp_info *lwp = (struct lwp_info *) lp;
>> +
>> +      /* The actual update is done later, we just mark that the register
>> +        needs updating.  */
>> +      lwp->arch_private->debug_registers_changed = 1;
>> +    }
>
> Thanks, this is likely more non-stop friendly than the win32 version.
> We can just send a SIGSTOP to each thread that is stopped, and set
> stop_expected.  Then, the debug register updating just works.  (we'll
> still need to make sure that moribund locations work with watchpoints
> though)
>
>
>> Index: utils.c
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/gdbserver/utils.c,v
>> retrieving revision 1.18
>> diff -u -p -r1.18 utils.c
>> --- utils.c     19 Jan 2009 00:16:46 -0000      1.18
>> +++ utils.c     1 Jun 2009 22:02:43 -0000
>> @@ -170,3 +170,37 @@ warning (const char *string,...)
>>    fprintf (stderr, "\n");
>>    va_end (args);
>>  }
>> +
>> +/* temporary storage using circular buffer */
>
> More bogus formatting copied from GDB.  Full sentence: capitalize, period,
> double space.

k.

>> +#define NUMCELLS 4
>> +#define CELLSIZE 50
>> +static char *
>> +get_cell (void)
>> +{
>> +  static char buf[NUMCELLS][CELLSIZE];
>> +  static int cell = 0;
>> +  if (++cell >= NUMCELLS)
>> +    cell = 0;
>> +  return buf[cell];
>> +}
>> +
>
>
> Otherwise, this is looking good to me.  I still feel that
> exposing the debug registers to GDB (as per-process wide
> registers), as opposed to using Z packets would be an
> alternative worth investigating, that would avoid having
> to mostly copy i386-nat.c to gdbserver/i386-low.c.  But,
> the Z packets interface already exists, so, that can
> always be investigated at any later time...

Setting aside breakpoints+watchpoints -> "points",
http://sourceware.org/ml/gdb-patches/2009-06/msg00594.html
how about this?

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2009-06-22  Doug Evans  <dje@google.com>
	    Pierre Muller  <muller@ics.u-strasbg.fr>

	* Makefile.in (SFILES): Add i386-low.c
	(i386_low_h): Define.
	(i386-low.o): Add dependencies.
	(linux-x86-low.o): Add i386-low.h dependency.
	(win32-i386-low.o): Ditto.
	* i386-low.c: New file.
	* i386-low.h: New file.
	* configure.srv (i[34567]86-*-cygwin*): Add i386-low.o to srv_tgtobj.
	(i[34567]86-*-linux*, i[34567]86-*-mingw*, x86_64-*-linux*): Ditto.
	* linux-low.c (linux_add_process): Initialize arch_private.
	(linux_remove_process): Free arch_private.
	(add_lwp): Initialize arch_private.
	(delete_lwp): Free arch_private.
	(linux_resume_one_lwp): Call the_low_target.prepare_to_resume if
	provided.
	* linux-low.h (process_info_private): New member arch_private.
	(lwp_info): New member arch_private.
	(linux_target_ops): New members new_process, new_thread,
	prepare_to_resume.
	(ptid_of): New macro.
	* linux-x86-low.c: Include stddef.h, i386-low.h.
	(arch_process_info): New struct.
	(arch_lwp_info): New struct.
	(x86_linux_dr_get, x86_linux_dr_set): New functions.
	(i386_dr_low_set_addr, i386_dr_low_set_control): New functions.
	(i386_dr_low_get_status): New function.
	(x86_insert_watchpoint, x86_remove_watchpoint): New functions.
	(x86_stopped_by_watchpoint): New function.
	(x86_stopped_data_address): New function.
	(x86_linux_new_process, x86_linux_new_thread): New functions.
	(x86_linux_prepare_to_resume): New function.
	(the_low_target): Add entries for insert_watchpoint, remove_watchpoint,
	stopped_by_watchpoint, stopped_data_address, new_process, new_thread,
	prepare_to_resume.
	* server.c (debug_hw_points): New global.
	(monitor_show_help): Document set debug-hw-points.
	* server.h (debug_hw_points): Declare.
	(paddr): Declare.
	* utils.c (NUMCELLS, CELLSIZE): New macros.
	(get_sell, xsnprintf, paddr): New functions.
	* win32-arm-low.c (the_low_target): Add entries for insert_watchpoint,
	remove_watchpoint, stopped_by_watchpoint, stopped_data_address.
	* win32-i386-low.c: Include i386-low.h.
	(debug_reg_state): Replaces dr.
	(i386_dr_low_set_addr, i386_dr_low_set_control): New functions.
	(i386_dr_low_get_status): New function.
	(i386_insert_watchpoint, i386_remove_watchpoint): New functions.
	(i386_stopped_by_watchpoint): New function.
	(i386_stopped_data_address): New function.
	(i386_initial_stuff): Update.
	(get_thread_context,set_thread_context,i386_thread_added): Update.
	(the_low_target): Add entries for insert_watchpoint,
	remove_watchpoint, stopped_by_watchpoint, stopped_data_address.
	* win32-low.c (win32_insert_watchpoint): New function.
	(win32_remove_watchpoint): New function.
	(win32_stopped_by_watchpoint): New function.
	(win32_stopped_data_address): New function.
	(win32_target_ops): Add entries for insert_watchpoint,
	remove_watchpoint, stopped_by_watchpoint, stopped_data_address.
	* win32-low.h (win32_target_ops): New members insert_watchpoint,
	remove_watchpoint, stopped_by_watchpoint, stopped_data_address.

Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/Makefile.in,v
retrieving revision 1.74
diff -u -p -r1.74 Makefile.in
--- Makefile.in	12 May 2009 22:25:00 -0000	1.74
+++ Makefile.in	23 Jun 2009 06:35:45 -0000
@@ -104,7 +104,7 @@ SFILES=	$(srcdir)/gdbreplay.c $(srcdir)/
 	$(srcdir)/thread-db.c $(srcdir)/utils.c \
 	$(srcdir)/linux-arm-low.c $(srcdir)/linux-cris-low.c \
 	$(srcdir)/linux-crisv32-low.c \
-	$(srcdir)/i387-fp.c \
+	${srcdir}/i386-low.c $(srcdir)/i387-fp.c \
 	$(srcdir)/linux-ia64-low.c $(srcdir)/linux-low.c \
 	$(srcdir)/linux-m32r-low.c \
 	$(srcdir)/linux-m68k-low.c $(srcdir)/linux-mips-low.c \
@@ -287,6 +287,10 @@ signals.o: ../common/signals.c $(server_
 memmem.o: ../gnulib/memmem.c
 	$(CC) -o memmem.o -c $(CPPFLAGS) $(INTERNAL_CFLAGS) $<
 
+i386_low_h = $(srcdir)/i386-low.h
+
+i386-low.o: i386-low.c $(i386_low_h) $(server_h) $(target_h)
+
 i387-fp.o: i387-fp.c $(server_h)
 
 linux-low.o: linux-low.c $(linux_low_h) $(server_h)
@@ -304,7 +308,7 @@ linux-ppc-low.o: linux-ppc-low.c $(linux
 linux-s390-low.o: linux-s390-low.c $(linux_low_h) $(server_h)
 linux-sh-low.o: linux-sh-low.c $(linux_low_h) $(server_h)
 linux-x86-low.o: linux-x86-low.c $(linux_low_h) $(server_h) \
-	$(gdb_proc_service_h)
+	$(gdb_proc_service_h) $(i386_low_h)
 linux-xtensa-low.o: linux-xtensa-low.c xtensa-xtregs.c $(linux_low_h) $(server_h)
 
 win32_low_h = $(srcdir)/win32-low.h
@@ -312,7 +316,7 @@ win32_low_h = $(srcdir)/win32-low.h
 win32-low.o: win32-low.c $(win32_low_h) $(server_h) $(regdef_h) $(regcache_h)
 
 win32-arm-low.o: win32-arm-low.c $(win32_low_h) $(server_h)
-win32-i386-low.o: win32-i386-low.c $(win32_low_h) $(server_h)
+win32-i386-low.o: win32-i386-low.c $(win32_low_h) $(server_h) $(i386_low_h)
 
 spu-low.o: spu-low.c $(server_h)
 
Index: configure.srv
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/configure.srv,v
retrieving revision 1.41
diff -u -p -r1.41 configure.srv
--- configure.srv	12 May 2009 22:25:00 -0000	1.41
+++ configure.srv	23 Jun 2009 06:35:45 -0000
@@ -53,10 +53,10 @@ case "${target}" in
 			srv_linux_thread_db=yes
 			;;
   i[34567]86-*-cygwin*)	srv_regobj=reg-i386.o
-			srv_tgtobj="win32-low.o win32-i386-low.o"
+			srv_tgtobj="i386-low.o win32-low.o win32-i386-low.o"
 			;;
   i[34567]86-*-linux*)	srv_regobj=reg-i386-linux.o
-			srv_tgtobj="linux-low.o linux-x86-low.o i387-fp.o"
+			srv_tgtobj="linux-low.o linux-x86-low.o i386-low.o i387-fp.o"
 			srv_linux_usrregs=yes
 			srv_linux_regsets=yes
 			srv_linux_thread_db=yes
@@ -71,7 +71,7 @@ case "${target}" in
 			srv_mingwce=yes
 			;;
   i[34567]86-*-mingw*)	srv_regobj=reg-i386.o
-			srv_tgtobj="win32-low.o win32-i386-low.o"
+			srv_tgtobj="i386-low.o win32-low.o win32-i386-low.o"
 			srv_mingw=yes
 			;;
   ia64-*-linux*)	srv_regobj=reg-ia64.o
@@ -170,7 +170,7 @@ case "${target}" in
 			srv_tgtobj="spu-low.o"
 			;;
   x86_64-*-linux*)	srv_regobj="reg-x86-64-linux.o reg-i386-linux.o"
-			srv_tgtobj="linux-low.o linux-x86-low.o i387-fp.o"
+			srv_tgtobj="linux-low.o linux-x86-low.o i386-low.o i387-fp.o"
 			srv_linux_usrregs=yes # This is for i386 progs.
 			srv_linux_regsets=yes
 			srv_linux_thread_db=yes
Index: i386-low.c
===================================================================
RCS file: i386-low.c
diff -N i386-low.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ i386-low.c	23 Jun 2009 06:35:45 -0000
@@ -0,0 +1,575 @@
+/* Debug register code for the i386.
+
+   Copyright (C) 2009
+   Free Software Foundation, Inc.
+
+   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 3 of the License, or
+   (at your option) any later version.
+
+   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.
+
+   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 "server.h"
+#include "target.h"
+#include "i386-low.h"
+
+/* Support for 8-byte wide hw watchpoints.  */
+#ifndef TARGET_HAS_DR_LEN_8
+/* NOTE: sizeof (long) == 4 on win64.  */
+#define TARGET_HAS_DR_LEN_8 (sizeof (void *) == 8)
+#endif
+
+enum target_hw_bp_type
+  {
+    hw_write   = 0,	/* Common  HW watchpoint */
+    hw_read    = 1,	/* Read    HW watchpoint */
+    hw_access  = 2,	/* Access  HW watchpoint */
+    hw_execute = 3	/* Execute HW breakpoint */
+  };
+
+/* DR7 Debug Control register fields.  */
+
+/* How many bits to skip in DR7 to get to R/W and LEN fields.  */
+#define DR_CONTROL_SHIFT	16
+/* How many bits in DR7 per R/W and LEN field for each watchpoint.  */
+#define DR_CONTROL_SIZE		4
+
+/* Watchpoint/breakpoint read/write fields in DR7.  */
+#define DR_RW_EXECUTE	(0x0)	/* Break on instruction execution.  */
+#define DR_RW_WRITE	(0x1)	/* Break on data writes.  */
+#define DR_RW_READ	(0x3)	/* Break on data reads or writes.  */
+
+/* This is here for completeness.  No platform supports this
+   functionality yet (as of March 2001).  Note that the DE flag in the
+   CR4 register needs to be set to support this.  */
+#ifndef DR_RW_IORW
+#define DR_RW_IORW	(0x2)	/* Break on I/O reads or writes.  */
+#endif
+
+/* Watchpoint/breakpoint length fields in DR7.  The 2-bit left shift
+   is so we could OR this with the read/write field defined above.  */
+#define DR_LEN_1	(0x0 << 2) /* 1-byte region watch or breakpoint.  */
+#define DR_LEN_2	(0x1 << 2) /* 2-byte region watch.  */
+#define DR_LEN_4	(0x3 << 2) /* 4-byte region watch.  */
+#define DR_LEN_8	(0x2 << 2) /* 8-byte region watch (AMD64).  */
+
+/* Local and Global Enable flags in DR7.
+
+   When the Local Enable flag is set, the breakpoint/watchpoint is
+   enabled only for the current task; the processor automatically
+   clears this flag on every task switch.  When the Global Enable flag
+   is set, the breakpoint/watchpoint is enabled for all tasks; the
+   processor never clears this flag.
+
+   Currently, all watchpoint are locally enabled.  If you need to
+   enable them globally, read the comment which pertains to this in
+   i386_insert_aligned_watchpoint below.  */
+#define DR_LOCAL_ENABLE_SHIFT	0 /* Extra shift to the local enable bit.  */
+#define DR_GLOBAL_ENABLE_SHIFT	1 /* Extra shift to the global enable bit.  */
+#define DR_ENABLE_SIZE		2 /* Two enable bits per debug register.  */
+
+/* Local and global exact breakpoint enable flags (a.k.a. slowdown
+   flags).  These are only required on i386, to allow detection of the
+   exact instruction which caused a watchpoint to break; i486 and
+   later processors do that automatically.  We set these flags for
+   backwards compatibility.  */
+#define DR_LOCAL_SLOWDOWN	(0x100)
+#define DR_GLOBAL_SLOWDOWN     	(0x200)
+
+/* Fields reserved by Intel.  This includes the GD (General Detect
+   Enable) flag, which causes a debug exception to be generated when a
+   MOV instruction accesses one of the debug registers.
+
+   FIXME: My Intel manual says we should use 0xF800, not 0xFC00.  */
+#define DR_CONTROL_RESERVED	(0xFC00)
+
+/* Auxiliary helper macros.  */
+
+/* A value that masks all fields in DR7 that are reserved by Intel.  */
+#define I386_DR_CONTROL_MASK	(~DR_CONTROL_RESERVED)
+
+/* The I'th debug register is vacant if its Local and Global Enable
+   bits are reset in the Debug Control register.  */
+#define I386_DR_VACANT(state, i) \
+  (((state)->dr_control_mirror & (3 << (DR_ENABLE_SIZE * (i)))) == 0)
+
+/* Locally enable the break/watchpoint in the I'th debug register.  */
+#define I386_DR_LOCAL_ENABLE(state, i) \
+  do { \
+    (state)->dr_control_mirror |= \
+      (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i))); \
+  } while (0)
+
+/* Globally enable the break/watchpoint in the I'th debug register.  */
+#define I386_DR_GLOBAL_ENABLE(state, i) \
+  do { \
+    (state)->dr_control_mirror |= \
+      (1 << (DR_GLOBAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i))); \
+  } while (0)
+
+/* Disable the break/watchpoint in the I'th debug register.  */
+#define I386_DR_DISABLE(state, i) \
+  do { \
+    (state)->dr_control_mirror &= \
+      ~(3 << (DR_ENABLE_SIZE * (i))); \
+  } while (0)
+
+/* Set in DR7 the RW and LEN fields for the I'th debug register.  */
+#define I386_DR_SET_RW_LEN(state, i,rwlen) \
+  do { \
+    (state)->dr_control_mirror &= \
+      ~(0x0f << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (i))); \
+    (state)->dr_control_mirror |= \
+      ((rwlen) << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (i))); \
+  } while (0)
+
+/* Get from DR7 the RW and LEN fields for the I'th debug register.  */
+#define I386_DR_GET_RW_LEN(state, i) \
+  (((state)->dr_control_mirror \
+    >> (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (i))) & 0x0f)
+
+/* Did the watchpoint whose address is in the I'th register break?  */
+#define I386_DR_WATCH_HIT(state,i) ((state)->dr_status_mirror & (1 << (i)))
+
+/* A macro to loop over all debug registers.  */
+#define ALL_DEBUG_REGISTERS(i)	for (i = 0; i < DR_NADDR; i++)
+
+/* Types of operations supported by i386_handle_nonaligned_watchpoint.  */
+typedef enum { WP_INSERT, WP_REMOVE, WP_COUNT } i386_wp_op_t;
+\f
+/* Implementation.  */
+
+/* Clear the reference counts and forget everything we knew about the
+   debug registers.  */
+
+void
+i386_low_init_dregs (struct i386_debug_reg_state *state)
+{
+  int i;
+
+  ALL_DEBUG_REGISTERS (i)
+    {
+      state->dr_mirror[i] = 0;
+      state->dr_ref_count[i] = 0;
+    }
+  state->dr_control_mirror = 0;
+  state->dr_status_mirror  = 0;
+}
+
+/* Print the values of the mirrored debug registers.  This is enabled via
+   the "set debug-hw-points 1" monitor command.  */
+
+static void
+i386_show_dr (struct i386_debug_reg_state *state,
+	      const char *func, CORE_ADDR addr,
+	      int len, enum target_hw_bp_type type)
+{
+  int i;
+
+  fprintf (stderr, "%s", func);
+  if (addr || len)
+    fprintf (stderr, " (addr=%lx, len=%d, type=%s)",
+	     (unsigned long) addr, len,
+	     type == hw_write ? "data-write"
+	     : (type == hw_read ? "data-read"
+		: (type == hw_access ? "data-read/write"
+		   : (type == hw_execute ? "instruction-execute"
+		      /* FIXME: if/when I/O read/write
+			 watchpoints are supported, add them
+			 here.  */
+		      : "??unknown??"))));
+  fprintf (stderr, ":\n");
+  fprintf (stderr, "\tCONTROL (DR7): %08x          STATUS (DR6): %08x\n",
+	   state->dr_control_mirror, state->dr_status_mirror);
+  ALL_DEBUG_REGISTERS (i)
+    {
+      fprintf (stderr, "\
+\tDR%d: addr=0x%s, ref.count=%d  DR%d: addr=0x%s, ref.count=%d\n",
+	      i, paddr (state->dr_mirror[i]),
+	      state->dr_ref_count[i],
+	      i + 1, paddr (state->dr_mirror[i + 1]),
+	      state->dr_ref_count[i + 1]);
+      i++;
+    }
+}
+
+/* Return the value of a 4-bit field for DR7 suitable for watching a
+   region of LEN bytes for accesses of type TYPE.  LEN is assumed to
+   have the value of 1, 2, or 4.  */
+
+static unsigned
+i386_length_and_rw_bits (int len, enum target_hw_bp_type type)
+{
+  unsigned rw;
+
+  switch (type)
+    {
+      case hw_execute:
+	rw = DR_RW_EXECUTE;
+	break;
+      case hw_write:
+	rw = DR_RW_WRITE;
+	break;
+      case hw_read:
+	/* The i386 doesn't support data-read watchpoints.  */
+      case hw_access:
+	rw = DR_RW_READ;
+	break;
+#if 0
+	/* Not yet supported.  */
+      case hw_io_access:
+	rw = DR_RW_IORW;
+	break;
+#endif
+      default:
+	error ("\
+Invalid hardware breakpoint type %d in i386_length_and_rw_bits.\n",
+			(int) type);
+    }
+
+  switch (len)
+    {
+      case 1:
+	return (DR_LEN_1 | rw);
+      case 2:
+	return (DR_LEN_2 | rw);
+      case 4:
+	return (DR_LEN_4 | rw);
+      case 8:
+        if (TARGET_HAS_DR_LEN_8)
+ 	  return (DR_LEN_8 | rw);
+      default:
+	error ("\
+Invalid hardware breakpoint length %d in i386_length_and_rw_bits.\n", len);
+    }
+}
+
+/* Insert a watchpoint at address ADDR, which is assumed to be aligned
+   according to the length of the region to watch.  LEN_RW_BITS is the
+   value of the bits from DR7 which describes the length and access
+   type of the region to be watched by this watchpoint.  Return 0 on
+   success, -1 on failure.  */
+
+static int
+i386_insert_aligned_watchpoint (struct i386_debug_reg_state *state,
+				CORE_ADDR addr, unsigned len_rw_bits)
+{
+  int i;
+
+  /* First, look for an occupied debug register with the same address
+     and the same RW and LEN definitions.  If we find one, we can
+     reuse it for this watchpoint as well (and save a register).  */
+  ALL_DEBUG_REGISTERS (i)
+    {
+      if (!I386_DR_VACANT (state, i)
+	  && state->dr_mirror[i] == addr
+	  && I386_DR_GET_RW_LEN (state, i) == len_rw_bits)
+	{
+	  state->dr_ref_count[i]++;
+	  return 0;
+	}
+    }
+
+  /* Next, look for a vacant debug register.  */
+  ALL_DEBUG_REGISTERS (i)
+    {
+      if (I386_DR_VACANT (state, i))
+	break;
+    }
+
+  /* No more debug registers!  */
+  if (i >= DR_NADDR)
+    return -1;
+
+  /* Now set up the register I to watch our region.  */
+
+  /* Record the info in our local mirrored array.  */
+  state->dr_mirror[i] = addr;
+  state->dr_ref_count[i] = 1;
+  I386_DR_SET_RW_LEN (state, i, len_rw_bits);
+  /* Note: we only enable the watchpoint locally, i.e. in the current
+     task.  Currently, no i386 target allows or supports global
+     watchpoints; however, if any target would want that in the
+     future, GDB should probably provide a command to control whether
+     to enable watchpoints globally or locally, and the code below
+     should use global or local enable and slow-down flags as
+     appropriate.  */
+  I386_DR_LOCAL_ENABLE (state, i);
+  state->dr_control_mirror |= DR_LOCAL_SLOWDOWN;
+  state->dr_control_mirror &= I386_DR_CONTROL_MASK;
+
+  /* Finally, actually pass the info to the inferior.  */
+  i386_dr_low_set_addr (state, i);
+  i386_dr_low_set_control (state);
+
+  return 0;
+}
+
+/* Remove a watchpoint at address ADDR, which is assumed to be aligned
+   according to the length of the region to watch.  LEN_RW_BITS is the
+   value of the bits from DR7 which describes the length and access
+   type of the region watched by this watchpoint.  Return 0 on
+   success, -1 on failure.  */
+
+static int
+i386_remove_aligned_watchpoint (struct i386_debug_reg_state *state,
+				CORE_ADDR addr, unsigned len_rw_bits)
+{
+  int i, retval = -1;
+
+  ALL_DEBUG_REGISTERS (i)
+    {
+      if (!I386_DR_VACANT (state, i)
+	  && state->dr_mirror[i] == addr
+	  && I386_DR_GET_RW_LEN (state, i) == len_rw_bits)
+	{
+	  if (--state->dr_ref_count[i] == 0) /* No longer in use?  */
+	    {
+	      /* Reset our mirror.  */
+	      state->dr_mirror[i] = 0;
+	      I386_DR_DISABLE (state, i);
+	      /* Reset it in the inferior.  */
+	      i386_dr_low_set_control (state);
+	      i386_dr_low_set_addr (state, i);
+	    }
+	  retval = 0;
+	}
+    }
+
+  return retval;
+}
+
+/* Insert or remove a (possibly non-aligned) watchpoint, or count the
+   number of debug registers required to watch a region at address
+   ADDR whose length is LEN for accesses of type TYPE.  Return 0 on
+   successful insertion or removal, a positive number when queried
+   about the number of registers, or -1 on failure.  If WHAT is not a
+   valid value, bombs through internal_error.  */
+
+static int
+i386_handle_nonaligned_watchpoint (struct i386_debug_reg_state *state,
+				   i386_wp_op_t what, CORE_ADDR addr, int len,
+				   enum target_hw_bp_type type)
+{
+  int retval = 0, status = 0;
+  int max_wp_len = TARGET_HAS_DR_LEN_8 ? 8 : 4;
+
+  static const int size_try_array[8][8] =
+  {
+    {1, 1, 1, 1, 1, 1, 1, 1},	/* Trying size one.  */
+    {2, 1, 2, 1, 2, 1, 2, 1},	/* Trying size two.  */
+    {2, 1, 2, 1, 2, 1, 2, 1},	/* Trying size three.  */
+    {4, 1, 2, 1, 4, 1, 2, 1},	/* Trying size four.  */
+    {4, 1, 2, 1, 4, 1, 2, 1},	/* Trying size five.  */
+    {4, 1, 2, 1, 4, 1, 2, 1},	/* Trying size six.  */
+    {4, 1, 2, 1, 4, 1, 2, 1},	/* Trying size seven.  */
+    {8, 1, 2, 1, 4, 1, 2, 1},	/* Trying size eight.  */
+  };
+
+  while (len > 0)
+    {
+      int align = addr % max_wp_len;
+      /* Four (eight on AMD64) is the maximum length a debug register
+	 can watch.  */
+      int try = (len > max_wp_len ? (max_wp_len - 1) : len - 1);
+      int size = size_try_array[try][align];
+
+      if (what == WP_COUNT)
+	{
+	  /* size_try_array[] is defined such that each iteration
+	     through the loop is guaranteed to produce an address and a
+	     size that can be watched with a single debug register.
+	     Thus, for counting the registers required to watch a
+	     region, we simply need to increment the count on each
+	     iteration.  */
+	  retval++;
+	}
+      else
+	{
+	  unsigned len_rw = i386_length_and_rw_bits (size, type);
+
+	  if (what == WP_INSERT)
+	    status = i386_insert_aligned_watchpoint (state, addr, len_rw);
+	  else if (what == WP_REMOVE)
+	    status = i386_remove_aligned_watchpoint (state, addr, len_rw);
+	  else
+	    fatal ("\
+Invalid value %d of operation in i386_handle_nonaligned_watchpoint.\n",
+		   (int) what);
+
+	  /* We keep the loop going even after a failure, because some
+	     of the other aligned watchpoints might still succeed
+	     (e.g. if they watch addresses that are already watched,
+	     in which case we just increment the reference counts of
+	     occupied debug registers).  If we break out of the loop
+	     too early, we could cause those addresses watched by
+	     other watchpoints to be disabled when breakpoint.c reacts
+	     to our failure to insert this watchpoint and tries to
+	     remove it.  */
+	  if (status)
+	    retval = status;
+	}
+
+      addr += size;
+      len -= size;
+    }
+
+  return retval;
+}
+
+#define Z_PACKET_WRITE_WP '2'
+#define Z_PACKET_READ_WP '3'
+#define Z_PACKET_ACCESS_WP '4'
+
+static int
+Z_packet_to_hw_type (char type)
+{
+  switch (type)
+    {
+    case Z_PACKET_WRITE_WP:
+      return hw_write;
+    case Z_PACKET_READ_WP:
+      return hw_read;
+    case Z_PACKET_ACCESS_WP:
+      return hw_access;
+    default:
+      error ("Z_packet_to_hw_type: bad watchpoint type %c", type);
+    }
+}
+
+/* Insert a watchpoint to watch a memory region which starts at
+   address ADDR and whose length is LEN bytes.  Watch memory accesses
+   of the type TYPE_FROM_PACKET.  Return 0 on success, -1 on failure.  */
+
+int
+i386_low_insert_watchpoint (struct i386_debug_reg_state *state,
+			    char type_from_packet, CORE_ADDR addr, int len)
+{
+  int retval;
+  int type = Z_packet_to_hw_type (type_from_packet);
+
+  if (((len != 1 && len != 2 && len != 4)
+       && !(TARGET_HAS_DR_LEN_8 && len == 8))
+      || addr % len != 0)
+    {
+      retval = i386_handle_nonaligned_watchpoint (state, WP_INSERT,
+						  addr, len, type);
+    }
+  else
+    {
+      unsigned len_rw = i386_length_and_rw_bits (len, type);
+
+      retval = i386_insert_aligned_watchpoint (state, addr, len_rw);
+    }
+
+  if (debug_hw_points)
+    i386_show_dr (state, "insert_watchpoint", addr, len, type);
+
+  return retval;
+}
+
+/* Remove a watchpoint that watched the memory region which starts at
+   address ADDR, whose length is LEN bytes, and for accesses of the
+   type TYPE_FROM_PACKET.  Return 0 on success, -1 on failure.  */
+
+int
+i386_low_remove_watchpoint (struct i386_debug_reg_state *state,
+			    char type_from_packet, CORE_ADDR addr, int len)
+{
+  int retval;
+  int type = Z_packet_to_hw_type (type_from_packet);
+
+  if (((len != 1 && len != 2 && len != 4)
+       && !(TARGET_HAS_DR_LEN_8 && len == 8))
+      || addr % len != 0)
+    {
+      retval = i386_handle_nonaligned_watchpoint (state, WP_REMOVE,
+						  addr, len, type);
+    }
+  else
+    {
+      unsigned len_rw = i386_length_and_rw_bits (len, type);
+
+      retval = i386_remove_aligned_watchpoint (state, addr, len_rw);
+    }
+
+  if (debug_hw_points)
+    i386_show_dr (state, "remove_watchpoint", addr, len, type);
+
+  return retval;
+}
+
+/* Return non-zero if we can watch a memory region that starts at
+   address ADDR and whose length is LEN bytes.  */
+
+int
+i386_low_region_ok_for_watchpoint (struct i386_debug_reg_state *state,
+				   CORE_ADDR addr, int len)
+{
+  int nregs;
+
+  /* Compute how many aligned watchpoints we would need to cover this
+     region.  */
+  nregs = i386_handle_nonaligned_watchpoint (state, WP_COUNT,
+					     addr, len, hw_write);
+  return nregs <= DR_NADDR ? 1 : 0;
+}
+
+/* If the inferior has some break/watchpoint that triggered, set the
+   address associated with that break/watchpoint and return true.
+   Otherwise, return false.  */
+
+int
+i386_low_stopped_data_address (struct i386_debug_reg_state *state,
+			       CORE_ADDR *addr_p)
+{
+  CORE_ADDR addr = 0;
+  int i;
+  int rc = 0;
+
+  /* Get dr_status_mirror for use by I386_DR_WATCH_HIT.  */
+  i386_dr_low_get_status (state);
+
+  ALL_DEBUG_REGISTERS (i)
+    {
+      if (I386_DR_WATCH_HIT (state, i)
+	  /* This second condition makes sure DRi is set up for a data
+	     watchpoint, not a hardware breakpoint.  The reason is
+	     that GDB doesn't call the target_stopped_data_address
+	     method except for data watchpoints.  In other words, I'm
+	     being paranoiac.  */
+	  && I386_DR_GET_RW_LEN (state, i) != 0)
+	{
+	  addr = state->dr_mirror[i];
+	  rc = 1;
+	  if (debug_hw_points)
+	    i386_show_dr (state, "watchpoint_hit", addr, -1, hw_write);
+	}
+    }
+
+  if (debug_hw_points && addr == 0)
+    i386_show_dr (state, "stopped_data_addr", 0, 0, hw_write);
+
+  if (rc)
+    *addr_p = addr;
+  return rc;
+}
+
+/* Return true if the inferior has some watchpoint that triggered.
+   Otherwise return false.  */
+
+int
+i386_low_stopped_by_watchpoint (struct i386_debug_reg_state *state)
+{
+  CORE_ADDR addr = 0;
+  return i386_low_stopped_data_address (state, &addr);
+}
Index: i386-low.h
===================================================================
RCS file: i386-low.h
diff -N i386-low.h
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ i386-low.h	23 Jun 2009 06:35:45 -0000
@@ -0,0 +1,109 @@
+/* Misc. low level support for i386.
+
+   Copyright (C) 2009
+   Free Software Foundation, Inc.
+
+   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 3 of the License, or
+   (at your option) any later version.
+
+   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.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Support for hardware watchpoints and breakpoints using the i386
+   debug registers.
+
+   This provides several functions for inserting and removing
+   hardware-assisted breakpoints and watchpoints, testing if one or
+   more of the watchpoints triggered and at what address, checking
+   whether a given region can be watched, etc.
+
+   The functions below implement debug registers sharing by reference
+   counts, and allow to watch regions up to 16 bytes long
+   (32 bytes on 64 bit hosts).  */
+
+
+/* Debug registers' indices.  */
+#define DR_FIRSTADDR 0
+#define DR_LASTADDR  3
+#define DR_NADDR     4 /* The number of debug address registers.  */
+#define DR_STATUS    6
+#define DR_CONTROL   7
+
+/* Global state needed to track h/w watchpoints.  */
+
+struct i386_debug_reg_state
+{
+  /* Mirror the inferior's DRi registers.  We keep the status and
+     control registers separated because they don't hold addresses.  */
+  CORE_ADDR dr_mirror[DR_NADDR];
+  unsigned dr_status_mirror, dr_control_mirror;
+
+  /* Reference counts for each debug register.  */
+  int dr_ref_count[DR_NADDR];
+};
+
+/* Initialize STATE.  */
+extern void i386_low_init_dregs (struct i386_debug_reg_state *state);
+
+/* Insert a watchpoint to watch a memory region which starts at
+   address ADDR and whose length is LEN bytes.  Watch memory accesses
+   of the type TYPE_FROM_PACKET.  Return 0 on success, -1 on failure.  */
+extern int i386_low_insert_watchpoint (struct i386_debug_reg_state *state,
+				       char type_from_packet, CORE_ADDR addr,
+				       int len);
+
+/* Remove a watchpoint that watched the memory region which starts at
+   address ADDR, whose length is LEN bytes, and for accesses of the
+   type TYPE_FROM_PACKET.  Return 0 on success, -1 on failure.  */
+extern int i386_low_remove_watchpoint (struct i386_debug_reg_state *state,
+				       char type_from_packet, CORE_ADDR addr,
+				       int len);
+
+/* Return non-zero if we can watch a memory region that starts at
+   address ADDR and whose length is LEN bytes.  */
+extern int i386_low_region_ok_for_watchpoint (struct i386_debug_reg_state *state,
+					      CORE_ADDR addr, int len);
+
+/* If the inferior has some break/watchpoint that triggered, set the
+   address associated with that break/watchpoint and return true.
+   Otherwise, return false.  */
+extern int i386_low_stopped_data_address (struct i386_debug_reg_state *state,
+					  CORE_ADDR *addr_p);
+
+/* Return true if the inferior has some watchpoint that triggered.
+   Otherwise return false.  */
+extern int i386_low_stopped_by_watchpoint (struct i386_debug_reg_state *state);
+\f
+/* Each target needs to provide several low-level functions
+   that will be called to insert watchpoints and hardware breakpoints
+   into the inferior, remove them, and check their status.  These
+   functions are:
+
+      i386_dr_low_set_control  -- set the debug control (DR7)
+				  register to a given value
+
+      i386_dr_low_set_addr     -- put an address into one debug register
+
+      i386_dr_low_get_status   -- return the value of the debug
+				  status (DR6) register.
+*/
+
+/* Update the inferior's debug register REGNUM from STATE.  */
+extern void i386_dr_low_set_addr (const struct i386_debug_reg_state *state,
+				  int regnum);
+
+/* Update the inferior's DR7 debug control register from STATE.  */
+extern void i386_dr_low_set_control (const struct i386_debug_reg_state *state);
+
+/* Get the value of the inferior's DR6 debug status register
+   and record it in STATE.  */
+extern void i386_dr_low_get_status (struct i386_debug_reg_state *state);
Index: linux-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/linux-low.c,v
retrieving revision 1.107
diff -u -p -r1.107 linux-low.c
--- linux-low.c	22 Jun 2009 19:33:41 -0000	1.107
+++ linux-low.c	23 Jun 2009 06:35:45 -0000
@@ -224,6 +224,7 @@ delete_lwp (struct lwp_info *lwp)
 {
   remove_thread (get_lwp_thread (lwp));
   remove_inferior (&all_lwps, &lwp->head);
+  free (lwp->arch_private);
   free (lwp);
 }
 
@@ -242,6 +243,9 @@ linux_add_process (int pid, int attached
   proc = add_process (pid, attached);
   proc->private = xcalloc (1, sizeof (*proc->private));
 
+  if (the_low_target.new_process != NULL)
+    proc->private->arch_private = the_low_target.new_process ();
+
   return proc;
 }
 
@@ -251,6 +255,7 @@ linux_add_process (int pid, int attached
 static void
 linux_remove_process (struct process_info *process)
 {
+  free (process->private->arch_private);
   free (process->private);
   remove_process (process);
 }
@@ -376,6 +381,9 @@ add_lwp (ptid_t ptid)
 
   lwp->head.id = ptid;
 
+  if (the_low_target.new_thread != NULL)
+    lwp->arch_private = the_low_target.new_thread ();
+
   add_inferior_to_list (&all_lwps, &lwp->head);
 
   return lwp;
@@ -466,7 +474,6 @@ linux_attach_lwp_1 (unsigned long lwpid,
   new_lwp = (struct lwp_info *) add_lwp (ptid);
   add_thread (ptid, new_lwp);
 
-
   /* We need to wait for SIGSTOP before being able to make the next
      ptrace call on this LWP.  */
   new_lwp->must_set_ptrace_flags = 1;
@@ -1740,6 +1747,9 @@ linux_resume_one_lwp (struct lwp_info *l
       *p_sig = NULL;
     }
 
+  if (the_low_target.prepare_to_resume != NULL)
+    the_low_target.prepare_to_resume (lwp);
+
   regcache_invalidate_one ((struct inferior_list_entry *)
 			   get_lwp_thread (lwp));
   errno = 0;
Index: linux-low.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/linux-low.h,v
retrieving revision 1.30
diff -u -p -r1.30 linux-low.h
--- linux-low.h	12 May 2009 22:25:00 -0000	1.30
+++ linux-low.h	23 Jun 2009 06:35:45 -0000
@@ -56,8 +56,13 @@ struct process_info_private
 
   /* Connection to the libthread_db library.  */
   td_thragent_t *thread_agent;
+
+  /* Target-specific additions.  */
+  struct arch_process_info *arch_private;
 };
 
+struct lwp_info;
+
 struct linux_target_ops
 {
   /* Architecture-specific setup.  */
@@ -96,10 +101,24 @@ struct linux_target_ops
      If DIRECTION is 1, then copy from INF to NATIVE.
      If DIRECTION is 0, copy from NATIVE to INF.  */
   int (*siginfo_fixup) (struct siginfo *native, void *inf, int direction);
+
+  /* Hook to call when a new process is created or attached to.
+     If the target needs per-process architecture-specific data,
+     allocate it here.  */
+  struct arch_process_info * (*new_process) (void);
+
+  /* Hook to call when a new thread is detected.
+     If the target needs per-thread architecture-specific data,
+     allocate it here.  */
+  struct arch_lwp_info * (*new_thread) (void);
+
+  /* Hook to call prior to resuming a thread.  */
+  void (*prepare_to_resume) (struct lwp_info *);
 };
 
 extern struct linux_target_ops the_low_target;
 
+#define ptid_of(proc) ((proc)->head.id)
 #define pid_of(proc) ptid_get_pid ((proc)->head.id)
 #define lwpid_of(proc) ptid_get_lwp ((proc)->head.id)
 
@@ -172,6 +191,9 @@ struct lwp_info
      THREAD_KNOWN is set.  */
   td_thrhandle_t th;
 #endif
+
+  /* Target-specific additions.  */
+  struct arch_lwp_info *arch_private;
 };
 
 extern struct inferior_list all_lwps;
Index: linux-x86-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/linux-x86-low.c,v
retrieving revision 1.2
diff -u -p -r1.2 linux-x86-low.c
--- linux-x86-low.c	13 May 2009 19:11:04 -0000	1.2
+++ linux-x86-low.c	23 Jun 2009 06:35:45 -0000
@@ -18,10 +18,12 @@
    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 <stddef.h>
 #include <signal.h>
 #include "server.h"
 #include "linux-low.h"
 #include "i387-fp.h"
+#include "i386-low.h"
 
 #include "gdb_proc_service.h"
 
@@ -56,6 +58,21 @@ void init_registers_x86_64_linux (void);
 #define ARCH_GET_GS 0x1004
 #endif
 
+/* Per-process arch-specific data we want to keep.  */
+
+struct arch_process_info
+{
+  struct i386_debug_reg_state debug_reg_state;
+};
+
+/* Per-thread arch-specific data we want to keep.  */
+
+struct arch_lwp_info
+{
+  /* Non-zero if our copy differs from what's recorded in the thread.  */
+  int debug_registers_changed;
+};
+
 #ifdef __x86_64__
 
 /* Mapping between the general-purpose registers in `struct user'
@@ -317,6 +334,176 @@ x86_breakpoint_at (CORE_ADDR pc)
   return 0;
 }
 \f
+/* Support for debug registers.  */
+
+static unsigned long
+x86_linux_dr_get (ptid_t ptid, int regnum)
+{
+  int tid;
+  unsigned long value;
+
+  tid = ptid_get_lwp (ptid);
+
+  errno = 0;
+  value = ptrace (PTRACE_PEEKUSER, tid,
+		  offsetof (struct user, u_debugreg[regnum]), 0);
+  if (errno != 0)
+    error ("Couldn't read debug register");
+
+  return value;
+}
+
+static void
+x86_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
+{
+  int tid;
+
+  tid = ptid_get_lwp (ptid);
+
+  errno = 0;
+  ptrace (PTRACE_POKEUSER, tid,
+	  offsetof (struct user, u_debugreg[regnum]), value);
+  if (errno != 0)
+    error ("Couldn't write debug register");
+}
+
+/* Update the inferior's debug register REGNUM from STATE.  */
+
+void
+i386_dr_low_set_addr (const struct i386_debug_reg_state *state, int regnum)
+{
+  struct inferior_list_entry *lp;
+  CORE_ADDR addr;
+
+  if (! (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR))
+    fatal ("Invalid debug register %d", regnum);
+
+  addr = state->dr_mirror[regnum];
+
+  /* ??? Will need tweaking for multi-process.  */
+  for (lp = all_lwps.head; lp; lp = lp->next)
+    {
+      struct lwp_info *lwp = (struct lwp_info *) lp;
+
+      /* The actual update is done later, we just mark that the register
+	 needs updating.  */
+      lwp->arch_private->debug_registers_changed = 1;
+    }
+}
+
+/* Update the inferior's DR7 debug control register from STATE.  */
+
+void
+i386_dr_low_set_control (const struct i386_debug_reg_state *state)
+{
+  struct inferior_list_entry *lp;
+
+  /* ??? Will need tweaking for multi-process.  */
+  for (lp = all_lwps.head; lp; lp = lp->next)
+    {
+      struct lwp_info *lwp = (struct lwp_info *) lp;
+
+      /* The actual update is done later, we just mark that the register
+	 needs updating.  */
+      lwp->arch_private->debug_registers_changed = 1;
+    }
+}
+
+/* Get the value of the DR6 debug status register from the inferior
+   and record it in STATE.  */
+
+void
+i386_dr_low_get_status (struct i386_debug_reg_state *state)
+{
+  struct lwp_info *lwp = get_thread_lwp (current_inferior);
+  ptid_t ptid = ptid_of (lwp);
+
+  state->dr_status_mirror = x86_linux_dr_get (ptid, DR_STATUS);
+}
+\f
+/* Watchpoint support.  */
+
+static int
+x86_insert_watchpoint (char type, CORE_ADDR addr, int len)
+{
+  struct process_info *proc = current_process ();
+  return i386_low_insert_watchpoint (&proc->private->arch_private->debug_reg_state,
+				     type, addr, len);
+}
+
+static int
+x86_remove_watchpoint (char type, CORE_ADDR addr, int len)
+{
+  struct process_info *proc = current_process ();
+  return i386_low_remove_watchpoint (&proc->private->arch_private->debug_reg_state,
+				     type, addr, len);
+}
+
+static int
+x86_stopped_by_watchpoint (void)
+{
+  struct process_info *proc = current_process ();
+  return i386_low_stopped_by_watchpoint (&proc->private->arch_private->debug_reg_state);
+}
+
+static CORE_ADDR
+x86_stopped_data_address (void)
+{
+  struct process_info *proc = current_process ();
+  CORE_ADDR addr;
+  if (i386_low_stopped_data_address (&proc->private->arch_private->debug_reg_state,
+				     &addr))
+    return addr;
+  return 0; /* ??? fatal?  */
+}
+\f
+/* Called when a new process is created.  */
+
+static struct arch_process_info *
+x86_linux_new_process (void)
+{
+  struct arch_process_info *info = xcalloc (1, sizeof (*info));
+
+  i386_low_init_dregs (&info->debug_reg_state);
+
+  return info;
+}
+
+/* Called when a new thread is detected.  */
+
+static struct arch_lwp_info *
+x86_linux_new_thread (void)
+{
+  struct arch_lwp_info *info = xcalloc (1, sizeof (*info));
+
+  info->debug_registers_changed = 1;
+
+  return info;
+}
+
+/* Called when resuming a thread.
+   If the debug regs have changed, update the thread's copies.  */
+
+static void
+x86_linux_prepare_to_resume (struct lwp_info *lwp)
+{
+  if (lwp->arch_private->debug_registers_changed)
+    {
+      int i;
+      ptid_t ptid = ptid_of (lwp);
+      int pid = ptid_get_pid (ptid);
+      struct process_info *proc = find_process_pid (pid);
+      struct i386_debug_reg_state *state = &proc->private->arch_private->debug_reg_state;
+
+      for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
+	x86_linux_dr_set (ptid, i, state->dr_mirror[i]);
+
+      x86_linux_dr_set (ptid, DR_CONTROL, state->dr_control_mirror);
+
+      lwp->arch_private->debug_registers_changed = 0;
+    }
+}
+\f
 /* When GDBSERVER is built as a 64-bit application on linux, the
    PTRACE_GETSIGINFO data is always presented in 64-bit layout.  Since
    debugging a 32-bit inferior with a 64-bit GDBSERVER should look the same
@@ -630,10 +817,10 @@ struct linux_target_ops the_low_target =
   NULL,
   1,
   x86_breakpoint_at,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
+  x86_insert_watchpoint,
+  x86_remove_watchpoint,
+  x86_stopped_by_watchpoint,
+  x86_stopped_data_address,
   /* collect_ptrace_register/supply_ptrace_register are not needed in the
      native i386 case (no registers smaller than an xfer unit), and are not
      used in the biarch case (HAVE_LINUX_USRREGS is not defined).  */
@@ -641,4 +828,7 @@ struct linux_target_ops the_low_target =
   NULL,
   /* need to fix up i386 siginfo if host is amd64 */
   x86_siginfo_fixup,
+  x86_linux_new_process,
+  x86_linux_new_thread,
+  x86_linux_prepare_to_resume
 };
Index: server.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/server.c,v
retrieving revision 1.98
diff -u -p -r1.98 server.c
--- server.c	19 Jun 2009 13:35:35 -0000	1.98
+++ server.c	23 Jun 2009 06:35:45 -0000
@@ -51,6 +51,9 @@ static char **program_argv, **wrapper_ar
    was originally used to debug LinuxThreads support.  */
 int debug_threads;
 
+/* Enable debugging of h/w breakpoint/watchpoint support.  */
+int debug_hw_points;
+
 int pass_signals[TARGET_SIGNAL_LAST];
 
 jmp_buf toplevel;
@@ -495,6 +498,8 @@ monitor_show_help (void)
   monitor_output ("The following monitor commands are supported:\n");
   monitor_output ("  set debug <0|1>\n");
   monitor_output ("    Enable general debugging messages\n");
+  monitor_output ("  set debug-hw-points <0|1>\n");
+  monitor_output ("    Enable h/w breakpoint/watchpoint debugging messages\n");
   monitor_output ("  set remote-debug <0|1>\n");
   monitor_output ("    Enable remote protocol debugging messages\n");
   monitor_output ("  exit\n");
@@ -1216,6 +1221,16 @@ handle_query (char *own_buf, int packet_
 	  debug_threads = 0;
 	  monitor_output ("Debug output disabled.\n");
 	}
+      else if (strcmp (mon, "set debug-hw-points 1") == 0)
+	{
+	  debug_hw_points = 1;
+	  monitor_output ("H/W point debugging output enabled.\n");
+	}
+      else if (strcmp (mon, "set debug-hw-points 0") == 0)
+	{
+	  debug_hw_points = 0;
+	  monitor_output ("H/W point debugging output disabled.\n");
+	}
       else if (strcmp (mon, "set remote-debug 1") == 0)
 	{
 	  remote_debug = 1;
Index: server.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/server.h,v
retrieving revision 1.58
diff -u -p -r1.58 server.h
--- server.h	24 May 2009 21:06:53 -0000	1.58
+++ server.h	23 Jun 2009 06:35:45 -0000
@@ -271,6 +271,7 @@ extern ptid_t step_thread;
 
 extern int server_waiting;
 extern int debug_threads;
+extern int debug_hw_points;
 extern int pass_signals[];
 
 extern jmp_buf toplevel;
@@ -407,6 +408,7 @@ void perror_with_name (const char *strin
 void error (const char *string,...) ATTR_NORETURN ATTR_FORMAT (printf, 1, 2);
 void fatal (const char *string,...) ATTR_NORETURN ATTR_FORMAT (printf, 1, 2);
 void warning (const char *string,...) ATTR_FORMAT (printf, 1, 2);
+char *paddr (CORE_ADDR addr);
 
 /* Maximum number of bytes to read/write at once.  The value here
    is chosen to fill up a packet (the headers account for the 32).  */
Index: utils.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/utils.c,v
retrieving revision 1.18
diff -u -p -r1.18 utils.c
--- utils.c	19 Jan 2009 00:16:46 -0000	1.18
+++ utils.c	23 Jun 2009 06:35:45 -0000
@@ -170,3 +170,37 @@ warning (const char *string,...)
   fprintf (stderr, "\n");
   va_end (args);
 }
+
+/* Temporary storage using circular buffer.  */
+#define NUMCELLS 4
+#define CELLSIZE 50
+static char *
+get_cell (void)
+{
+  static char buf[NUMCELLS][CELLSIZE];
+  static int cell = 0;
+  if (++cell >= NUMCELLS)
+    cell = 0;
+  return buf[cell];
+}
+
+static int
+xsnprintf (char *str, size_t size, const char *format, ...)
+{
+  va_list args;
+  int ret;
+
+  va_start (args, format);
+  ret = vsnprintf (str, size, format, args);
+  va_end (args);
+
+  return ret;
+}
+
+char *
+paddr (CORE_ADDR addr)
+{
+  char *str = get_cell ();
+  xsnprintf (str, CELLSIZE, "%lx", (long) addr);
+  return str;
+}
Index: win32-arm-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/win32-arm-low.c,v
retrieving revision 1.8
diff -u -p -r1.8 win32-arm-low.c
--- win32-arm-low.c	3 Jan 2009 05:57:57 -0000	1.8
+++ win32-arm-low.c	23 Jun 2009 06:35:45 -0000
@@ -122,4 +122,9 @@ struct win32_target_ops the_low_target =
   NULL, /* single_step */
   (const unsigned char *) &arm_wince_breakpoint,
   arm_wince_breakpoint_len,
+  /* Watchpoint related functions.  See target.h for comments.  */
+  NULL, /* insert_watchpoint */
+  NULL, /* remove_watchpoint */
+  NULL, /* stopped_by_watchpoint */
+  NULL  /* stopped_data_address */
 };
Index: win32-i386-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/win32-i386-low.c,v
retrieving revision 1.14
diff -u -p -r1.14 win32-i386-low.c
--- win32-i386-low.c	3 Jan 2009 05:57:57 -0000	1.14
+++ win32-i386-low.c	23 Jun 2009 06:35:45 -0000
@@ -17,6 +17,7 @@
 
 #include "server.h"
 #include "win32-low.h"
+#include "i386-low.h"
 
 #define FCS_REGNUM 27
 #define FOP_REGNUM 31
@@ -26,15 +27,83 @@
 /* Defined in auto-generated file reg-i386.c.  */
 void init_registers_i386 (void);
 
-static unsigned dr[8];
+static struct i386_debug_reg_state debug_reg_state;
 
 static int debug_registers_changed = 0;
 static int debug_registers_used = 0;
 
+/* Update the inferior's debug register REGNUM from STATE.  */
+
+void
+i386_dr_low_set_addr (const struct i386_debug_reg_state *state, int regnum)
+{
+  if (! (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR))
+    fatal ("Invalid debug register %d", regnum);
+
+  /* debug_reg_state.dr_mirror is already set.
+     Just notify i386_set_thread_context, i386_thread_added
+     that the registers need to be updated.  */
+  debug_registers_changed = 1;
+  debug_registers_used = 1;
+}
+
+/* Update the inferior's DR7 debug control register from STATE.  */
+
+void
+i386_dr_low_set_control (const struct i386_debug_reg_state *state)
+{
+  /* debug_reg_state.dr_control_mirror is already set.
+     Just notify i386_set_thread_context, i386_thread_added
+     that the registers need to be updated.  */
+  debug_registers_changed = 1;
+  debug_registers_used = 1;
+}
+
+/* Get the value of the DR6 debug status register from the inferior
+   and record it in STATE.  */
+
+void
+i386_dr_low_get_status (struct i386_debug_reg_state *state)
+{
+  /* We don't need to do anything here, the last call to thread_rec for
+     current_event.dwThreadId id has already set it.  */
+}
+
+/* Watchpoint support.  */
+
+static int
+i386_insert_watchpoint (char type, CORE_ADDR addr, int len)
+{
+  return i386_low_insert_watchpoint (&debug_reg_state,
+				     type, addr, len);
+}
+
+static int
+i386_remove_watchpoint (char type, CORE_ADDR addr, int len)
+{
+  return i386_low_remove_watchpoint (&debug_reg_state,
+				     type, addr, len);
+}
+
+static int
+i386_stopped_by_watchpoint (void)
+{
+  return i386_low_stopped_by_watchpoint (&debug_reg_state);
+}
+
+static CORE_ADDR
+i386_stopped_data_address (void)
+{
+  CORE_ADDR addr;
+  if (i386_low_stopped_data_address (&debug_reg_state, &addr))
+    return addr;
+  return 0; /* ??? fatal?  */
+}
+
 static void
 i386_initial_stuff (void)
 {
-  memset (&dr, 0, sizeof (dr));
+  i386_low_init_dregs (&debug_reg_state);
   debug_registers_changed = 0;
   debug_registers_used = 0;
 }
@@ -55,12 +124,13 @@ i386_get_thread_context (win32_thread_in
   if (th->tid == current_event->dwThreadId)
     {
       /* Copy dr values from the current thread.  */
-      dr[0] = th->context.Dr0;
-      dr[1] = th->context.Dr1;
-      dr[2] = th->context.Dr2;
-      dr[3] = th->context.Dr3;
-      dr[6] = th->context.Dr6;
-      dr[7] = th->context.Dr7;
+      struct i386_debug_reg_state *dr = &debug_reg_state;
+      dr->dr_mirror[0] = th->context.Dr0;
+      dr->dr_mirror[1] = th->context.Dr1;
+      dr->dr_mirror[2] = th->context.Dr2;
+      dr->dr_mirror[3] = th->context.Dr3;
+      dr->dr_status_mirror = th->context.Dr6;
+      dr->dr_control_mirror = th->context.Dr7;
     }
 }
 
@@ -69,13 +139,14 @@ i386_set_thread_context (win32_thread_in
 {
   if (debug_registers_changed)
     {
-      th->context.Dr0 = dr[0];
-      th->context.Dr1 = dr[1];
-      th->context.Dr2 = dr[2];
-      th->context.Dr3 = dr[3];
-      /* th->context.Dr6 = dr[6];
+      struct i386_debug_reg_state *dr = &debug_reg_state;
+      th->context.Dr0 = dr->dr_mirror[0];
+      th->context.Dr1 = dr->dr_mirror[1];
+      th->context.Dr2 = dr->dr_mirror[2];
+      th->context.Dr3 = dr->dr_mirror[3];
+      /* th->context.Dr6 = dr->dr_status_mirror;
 	 FIXME: should we set dr6 also ?? */
-      th->context.Dr7 = dr[7];
+      th->context.Dr7 = dr->dr_control_mirror;
     }
 
   SetThreadContext (th->h, &th->context);
@@ -87,16 +158,17 @@ i386_thread_added (win32_thread_info *th
   /* Set the debug registers for the new thread if they are used.  */
   if (debug_registers_used)
     {
+      struct i386_debug_reg_state *dr = &debug_reg_state;
       th->context.ContextFlags = CONTEXT_DEBUG_REGISTERS;
       GetThreadContext (th->h, &th->context);
 
-      th->context.Dr0 = dr[0];
-      th->context.Dr1 = dr[1];
-      th->context.Dr2 = dr[2];
-      th->context.Dr3 = dr[3];
-      /* th->context.Dr6 = dr[6];
+      th->context.Dr0 = dr->dr_mirror[0];
+      th->context.Dr1 = dr->dr_mirror[1];
+      th->context.Dr2 = dr->dr_mirror[2];
+      th->context.Dr3 = dr->dr_mirror[3];
+      /* th->context.Dr6 = dr->dr_status_mirror;
 	 FIXME: should we set dr6 also ?? */
-      th->context.Dr7 = dr[7];
+      th->context.Dr7 = dr->dr_control_mirror;
 
       SetThreadContext (th->h, &th->context);
       th->context.ContextFlags = 0;
@@ -205,4 +277,8 @@ struct win32_target_ops the_low_target =
   i386_single_step,
   NULL, /* breakpoint */
   0, /* breakpoint_len */
+  i386_insert_watchpoint,
+  i386_remove_watchpoint,
+  i386_stopped_by_watchpoint,
+  i386_stopped_data_address
 };
Index: win32-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/win32-low.c,v
retrieving revision 1.36
diff -u -p -r1.36 win32-low.c
--- win32-low.c	22 Jun 2009 19:33:41 -0000	1.36
+++ win32-low.c	23 Jun 2009 06:35:45 -0000
@@ -228,6 +228,48 @@ child_delete_thread (DWORD pid, DWORD ti
   delete_thread_info (thread);
 }
 
+/* These watchpoint related wrapper functions simply pass on the function call
+   if the target has registered a corresponding function.  */
+
+static int
+win32_insert_watchpoint (char type, CORE_ADDR addr, int len)
+{
+  if (the_low_target.insert_watchpoint != NULL)
+    return the_low_target.insert_watchpoint (type, addr, len);
+  else
+    /* Unsupported (see target.h).  */
+    return 1;
+}
+
+static int
+win32_remove_watchpoint (char type, CORE_ADDR addr, int len)
+{
+  if (the_low_target.remove_watchpoint != NULL)
+    return the_low_target.remove_watchpoint (type, addr, len);
+  else
+    /* Unsupported (see target.h).  */
+    return 1;
+}
+
+static int
+win32_stopped_by_watchpoint (void)
+{
+  if (the_low_target.stopped_by_watchpoint != NULL)
+    return the_low_target.stopped_by_watchpoint ();
+  else
+    return 0;
+}
+
+static CORE_ADDR
+win32_stopped_data_address (void)
+{
+  if (the_low_target.stopped_data_address != NULL)
+    return the_low_target.stopped_data_address ();
+  else
+    return 0;
+}
+
+
 /* Transfer memory from/to the debugged process.  */
 static int
 child_xfer_memory (CORE_ADDR memaddr, char *our, int len,
@@ -1697,10 +1739,10 @@ static struct target_ops win32_target_op
   NULL,
   win32_request_interrupt,
   NULL,
-  NULL,
-  NULL,
-  NULL,
-  NULL,
+  win32_insert_watchpoint,
+  win32_remove_watchpoint,
+  win32_stopped_by_watchpoint,
+  win32_stopped_data_address,
   NULL,
   NULL,
   NULL,
Index: win32-low.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/win32-low.h,v
retrieving revision 1.9
diff -u -p -r1.9 win32-low.h
--- win32-low.h	3 Jan 2009 05:57:57 -0000	1.9
+++ win32-low.h	23 Jun 2009 06:35:45 -0000
@@ -70,6 +70,12 @@ struct win32_target_ops
 
   const unsigned char *breakpoint;
   int breakpoint_len;
+
+  /* Watchpoint related functions.  See target.h for comments.  */
+  int (*insert_watchpoint) (char type, CORE_ADDR addr, int len);
+  int (*remove_watchpoint) (char type, CORE_ADDR addr, int len);
+  int (*stopped_by_watchpoint) (void);
+  CORE_ADDR (*stopped_data_address) (void);
 };
 
 extern struct win32_target_ops the_low_target;