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

[Doug Evans <dje@google.com>]

Oh, btw, yes I know it needs updating 'cus i386/amd64 gdbserver is now
biarch.  :-)
That part is mechanical.
Is there anything that still needs discussing?

On Mon, May 18, 2009 at 4:11 PM, Doug Evans <dje@google.com> wrote:
> Ping.
>
> [for completeness sake, Pierre, I haven't forgotten about win32-i386-low.c. :-)]
>
> What can I do so that we can make some progress here?
>
> On Thu, Apr 30, 2009 at 12:18 AM, Doug Evans <dje@google.com> wrote:
>> Hi.
>>
>> I took Pierre's patch here
>> http://sourceware.org/ml/gdb-patches/2009-02/msg00206.html
>>
>> and added support for {i386,amd64}-linux.
>> Pierre, I _think_ I didn't break win32 support, but it is different
>> than what you originally wrote.  Can you test it?
>>
>> This patch assumes the gdbserver memory leak fix has been applied:
>> http://sourceware.org/ml/gdb-patches/2009-04/msg00803.html
>>
>>
>> 2009-04-29  Pierre Muller  <muller@ics.u-strasbg.fr>
>>            Doug Evans  <dje@google.com>
>>
>>        * Makefile.in (SFILES): Add i386-low.c
>>        (i386_low_h): Define.
>>        (i386-low.o): Add dependencies.
>>        (linux-i386-low.o): Add i386-low.h dependency.
>>        (linux-x86-64-low.o): Ditto.
>>        (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-i386-low.c: Include stddef.h, i386-low.h.
>>        (arch_process_info): New struct.
>>        (i386_linux_dr_get, i386_linux_dr_set): New functions.
>>        (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, i386_stopped_data_address): New functions.
>>        (i386_linux_new_process, i386_linux_new_thread): New functions.
>>        (the_low_target): Add entries for insert_watchpoint, remove_watchpoint,
>>        stopped_by_watchpoint, stopped_data_address, new_process, new_thread.
>>        * linux-low.c (linux_add_process): Initialize arch_private.
>>        (linux_remove_process): Free arch_private.
>>        (notify_low_target_new_thread): New function.
>>        (handle_extended_wait): Call it.
>>        (linux_attach_lwp_1, linux_wait_1): Ditto.
>>        (linux_insert_watchpoint): Update call to
>>        the_low_target.insert_watchpoint.
>>        (linux_remove_watchpoint): Update call to
>>        the_low_target.remove_watchpoint.
>>        (linux_stopped_by_watchpoint): Update call to
>>        the_low_target.stopped_by_watchpoint.
>>        (linux_stopped_data_address): Update call to
>>        the_low_target.stopped_data_address.
>>        * linux-low.h (process_info_private): New member arch_private.
>>        (linux_target_ops): Add arch_private parameter to insert_watchpoint,
>>        remove_watchpoint, stopped_by_watchpoint, stopped_data_address.
>>        New members new_process, new_thread.
>>        (ptid_of, PIDGET, TIDGET): New macros.
>>        * linux-x86-64-low.c: Include stddef.h, i386-low.h.
>>        (arch_process_info): New struct.
>>        (x86_64_linux_dr_get, x86_64_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_64_insert_watchpoint, x86_64_remove_watchpoint): New functions.
>>        (x86_64_stopped_by_watchpoint): New function.
>>        (x86_64_stopped_data_address): New function.
>>        (x86_64_linux_new_process, x86_64_linux_new_thread): New functions.
>>        (the_low_target): Add entries for insert_watchpoint, remove_watchpoint,
>>        stopped_by_watchpoint, stopped_data_address, new_process, new_thread.
>>        * server.h (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.
>>        (i386_dr_low_set_addr, i386_dr_low_set_control): New functions.
>>        (i386_dr_low_get_status): New function.
>>        (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 1.73
>> diff -u -p -r1.73 Makefile.in
>> --- Makefile.in 1 Apr 2009 22:48:05 -0000       1.73
>> +++ Makefile.in 30 Apr 2009 01:23:29 -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)/linux-i386-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)
>> @@ -297,7 +301,7 @@ linux-arm-low.o: linux-arm-low.c $(linux
>>  linux-cris-low.o: linux-cris-low.c $(linux_low_h) $(server_h)
>>  linux-crisv32-low.o: linux-crisv32-low.c $(linux_low_h) $(server_h)
>>  linux-i386-low.o: linux-i386-low.c $(linux_low_h) $(server_h) \
>> -       $(gdb_proc_service_h)
>> +       $(gdb_proc_service_h) $(i386_low_h)
>>  linux-ia64-low.o: linux-ia64-low.c $(linux_low_h) $(server_h)
>>  linux-m32r-low.o: linux-m32r-low.c $(linux_low_h) $(server_h)
>>  linux-mips-low.o: linux-mips-low.c $(linux_low_h) $(server_h) \
>> @@ -306,7 +310,7 @@ 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-x86-64-low.o: linux-x86-64-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
>> @@ -314,7 +318,7 @@ 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 $(server_h)
>>
>> Index: configure.srv
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/gdbserver/configure.srv,v
>> retrieving revision 1.40
>> diff -u -p -r1.40 configure.srv
>> --- configure.srv       19 Apr 2009 17:54:52 -0000      1.40
>> +++ configure.srv       30 Apr 2009 01:23:29 -0000
>> @@ -53,10 +53,10 @@ case "${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-i386-low.o i387-fp.o"
>> +                       srv_tgtobj="linux-low.o linux-i386-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
>> -                       srv_tgtobj="linux-low.o linux-x86-64-low.o i387-fp.o"
>> +                       srv_tgtobj="linux-low.o linux-x86-64-low.o i386-low.o i387-fp.o"
>>                        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  30 Apr 2009 01:23:29 -0000
>> @@ -0,0 +1,667 @@
>> +/* 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
>> +#define TARGET_HAS_DR_LEN_8 (sizeof (long) == 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++)
>> +
>> +/* Whether or not to print the mirrored debug registers.  */
>> +static int maint_show_dr = 0;
>> +
>> +/* 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 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);
>> +
>> +/* 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;
>> +}
>> +
>> +/* 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.  */
>> +
>> +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++;
>> +    }
>> +}
>> +
>> +/* 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 (i, addr);
>> +  i386_dr_low_set_control (state->dr_control_mirror);
>> +
>> +  return 0;
>> +}
>> +
>> +/* Reset a watched address for debug reg DR.
>> +   All implementations just do foo_set_addr (addr, 0), so this is a wrapper
>> +   around foo_set_addr to maintain the concept that this is a reset.  */
>> +
>> +static void
>> +i386_dr_low_reset_addr (int dr)
>> +{
>> +  i386_dr_low_set_addr (dr, 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->dr_control_mirror);
>> +             i386_dr_low_reset_addr (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 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);
>> +#if 0
>> +         else
>> +           internal_error (__FILE__, __LINE__, _("\
>> +Invalid value %d of operation in i386_handle_nonaligned_watchpoint.\n"),
>> +                           (int)what);
>> +#endif
>> +         /* 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 (maint_show_dr)
>> +    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 (maint_show_dr)
>> +    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 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;
>> +  int rc = 0;
>> +
>> +  state->dr_status_mirror = i386_dr_low_get_status ();
>> +
>> +  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 (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;
>> +}
>> +
>> +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);
>> +}
>> +
>> +/* Support for h/w breakpoints.
>> +   This support is not currently used, kept for reference.  */
>> +
>> +/* Return non-zero if the inferior has some break/watchpoint that
>> +   triggered.  */
>> +
>> +int
>> +i386_low_stopped_by_hwbp (struct i386_debug_reg_state *state)
>> +{
>> +  int i;
>> +
>> +  state->dr_status_mirror = i386_dr_low_get_status ();
>> +  if (maint_show_dr)
>> +    i386_show_dr (state, "stopped_by_hwbp", 0, 0, hw_execute);
>> +
>> +  ALL_DEBUG_REGISTERS(i)
>> +    {
>> +      if (I386_DR_WATCH_HIT (state, i))
>> +       return 1;
>> +    }
>> +
>> +  return 0;
>> +}
>> +
>> +/* Insert a hardware-assisted breakpoint at ADDR.
>> +   Return 0 on success, -1 on failure.  */
>> +
>> +int
>> +i386_low_insert_hw_breakpoint (struct i386_debug_reg_state *state,
>> +                              CORE_ADDR addr)
>> +{
>> +  unsigned len_rw = i386_length_and_rw_bits (1, hw_execute);
>> +  int retval = i386_insert_aligned_watchpoint (state, addr, len_rw);
>> +
>> +  if (maint_show_dr)
>> +    i386_show_dr (state, "insert_hwbp", addr, 1, hw_execute);
>> +
>> +  return retval;
>> +}
>> +
>> +/* Remove a hardware-assisted breakpoint at ADDR.
>> +   Return 0 on success, -1 on failure.  */
>> +
>> +int
>> +i386_low_remove_hw_breakpoint (struct i386_debug_reg_state *state,
>> +                              CORE_ADDR addr)
>> +{
>> +  unsigned len_rw = i386_length_and_rw_bits (1, hw_execute);
>> +  int retval = i386_remove_aligned_watchpoint (state, addr, len_rw);
>> +
>> +  if (maint_show_dr)
>> +    i386_show_dr (state, "remove_hwbp", addr, 1, hw_execute);
>> +
>> +  return retval;
>> +}
>> 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  30 Apr 2009 01:23:29 -0000
>> @@ -0,0 +1,118 @@
>> +/* 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];
>> +};
>> +
>> +/* Clear the reference counts and forget everything we knew about DRi.  */
>> +extern void i386_low_cleanup_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 CORE_ADDR i386_low_stopped_data_address (struct i386_debug_reg_state *state);
>> +
>> +extern int i386_low_stopped_by_watchpoint (struct i386_debug_reg_state *state);
>> +
>> +/* Return non-zero if the inferior has some break/watchpoint that
>> +   triggered.  */
>> +extern int i386_low_stopped_by_hwbp (struct i386_debug_reg_state *state);
>> +
>> +/* Insert a hardware-assisted breakpoint at ADDR.
>> +   Return 0 on success, -1 on failure.  */
>> +extern int i386_low_insert_hw_breakpoint (struct i386_debug_reg_state *state,
>> +                                         CORE_ADDR addr);
>> +
>> +/* Remove a hardware-assisted breakpoint at ADDR.
>> +   Return 0 on success, -1 on failure.  */
>> +extern int i386_low_remove_hw_breakpoint (struct i386_debug_reg_state *state,
>> +                                         CORE_ADDR addr);
>> +
>> +/* 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.
>> +*/
>> +
>> +/* Pass the address ADDR to the inferior in the I'th debug register.  */
>> +extern void i386_dr_low_set_addr (int i, CORE_ADDR addr);
>> +
>> +/* Pass the value VAL to the inferior in the DR7 debug control register.  */
>> +extern void i386_dr_low_set_control (unsigned val);
>> +
>> +/* Get the value of the DR6 debug status register from the inferior.  */
>> +extern unsigned i386_dr_low_get_status (void);
>> Index: linux-i386-low.c
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/gdbserver/linux-i386-low.c,v
>> retrieving revision 1.19
>> diff -u -p -r1.19 linux-i386-low.c
>> --- linux-i386-low.c    22 Mar 2009 23:57:10 -0000      1.19
>> +++ linux-i386-low.c    30 Apr 2009 01:23:29 -0000
>> @@ -17,9 +17,11 @@
>>    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 "server.h"
>>  #include "linux-low.h"
>>  #include "i387-fp.h"
>> +#include "i386-low.h"
>>
>>  #include "gdb_proc_service.h"
>>
>> @@ -33,10 +35,14 @@
>>  #define PTRACE_GET_THREAD_AREA 25
>>  #endif
>>
>> +struct arch_process_info
>> +{
>> +  struct i386_debug_reg_state debug_reg_state;
>> +};
>> +
>>  /* Defined in auto-generated file reg-i386-linux.c.  */
>>  void init_registers_i386_linux (void);
>>
>> -
>>  /* This module only supports access to the general purpose registers.  */
>>
>>  #define i386_num_regs 16
>> @@ -187,6 +193,148 @@ i386_breakpoint_at (CORE_ADDR pc)
>>
>>   return 0;
>>  }
>> +
>> +/* Support for debug registers.  */
>> +
>> +static unsigned long
>> +i386_linux_dr_get (ptid_t ptid, int regnum)
>> +{
>> +  int tid;
>> +  unsigned long value;
>> +
>> +  tid = TIDGET (ptid);
>> +  if (tid == 0)
>> +    tid = PIDGET (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
>> +i386_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
>> +{
>> +  int tid;
>> +
>> +  tid = TIDGET (ptid);
>> +  if (tid == 0)
>> +    tid = PIDGET (ptid);
>> +
>> +  errno = 0;
>> +  ptrace (PTRACE_POKEUSER, tid,
>> +         offsetof (struct user, u_debugreg[regnum]), value);
>> +  if (errno != 0)
>> +    error ("Couldn't write debug register");
>> +}
>> +
>> +/* Pass the address ADDR to the inferior in debug register REGNUM.  */
>> +
>> +void
>> +i386_dr_low_set_addr (int regnum, CORE_ADDR addr)
>> +{
>> +  struct inferior_list_entry *lp;
>> +
>> +  if (! (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR))
>> +    error ("Invalid debug register");
>> +
>> +  for (lp = all_lwps.head; lp; lp = lp->next)
>> +    {
>> +      struct lwp_info *lwp = (struct lwp_info *) lp;
>> +      i386_linux_dr_set (ptid_of (lwp), DR_FIRSTADDR + regnum, addr);
>> +    }
>> +}
>> +
>> +/* Pass the value VAL to the inferior in the DR7 debug control register.  */
>> +
>> +void
>> +i386_dr_low_set_control (unsigned control)
>> +{
>> +  struct inferior_list_entry *lp;
>> +
>> +  for (lp = all_lwps.head; lp; lp = lp->next)
>> +    {
>> +      struct lwp_info *lwp = (struct lwp_info *) lp;
>> +      i386_linux_dr_set (ptid_of (lwp), DR_CONTROL, control);
>> +    }
>> +}
>> +
>> +/* Get the value of the DR6 debug status register from the inferior.  */
>> +
>> +unsigned
>> +i386_dr_low_get_status (void)
>> +{
>> +  ptid_t inferior_ptid = ptid_of (get_thread_lwp (current_inferior));
>> +  return i386_linux_dr_get (inferior_ptid, DR_STATUS);
>> +}
>> +
>> +/* Watchpoint support.  */
>> +
>> +static int
>> +i386_insert_watchpoint (struct arch_process_info *arch_private,
>> +                       char type, CORE_ADDR addr, int len)
>> +{
>> +  return i386_low_insert_watchpoint (&arch_private->debug_reg_state,
>> +                                    type, addr, len);
>> +}
>> +
>> +static int
>> +i386_remove_watchpoint (struct arch_process_info *arch_private,
>> +                       char type, CORE_ADDR addr, int len)
>> +{
>> +  return i386_low_remove_watchpoint (&arch_private->debug_reg_state,
>> +                                    type, addr, len);
>> +}
>> +
>> +static int
>> +i386_stopped_by_watchpoint (struct arch_process_info *arch_private)
>> +{
>> +  return i386_low_stopped_by_watchpoint (&arch_private->debug_reg_state);
>> +}
>> +
>> +static CORE_ADDR
>> +i386_stopped_data_address (struct arch_process_info *arch_private)
>> +{
>> +  return i386_low_stopped_data_address (&arch_private->debug_reg_state);
>> +}
>> +
>> +/* Called when a new process is created.  */
>> +
>> +struct arch_process_info *
>> +i386_linux_new_process (int pid, int attached)
>> +{
>> +  struct arch_process_info *info = xcalloc (1, sizeof (*info));
>> +
>> +  return info;
>> +}
>> +
>> +/* Called when a new thread is detected.
>> +   INITIAL is non-zero for the main thread, zero otherwise.  */
>> +
>> +static void
>> +i386_linux_new_thread (struct lwp_info *lwp, int initial)
>> +{
>> +  /* The initial thread has debug regs set later during process
>> +     creation/attaching handling.  */
>> +
>> +  if (! initial)
>> +    {
>> +      int i;
>> +      ptid_t ptid = ptid_of (lwp);
>> +      int pid = PIDGET (ptid);
>> +      struct process_info *proc = find_process_pid (pid);
>> +      struct arch_process_info *arch_private = proc->private->arch_private;
>> +      struct i386_debug_reg_state *state = &arch_private->debug_reg_state;
>> +
>> +      for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
>> +       i386_linux_dr_set (ptid, i, state->dr_mirror[i]);
>> +
>> +      i386_linux_dr_set (ptid, DR_CONTROL, state->dr_control_mirror);
>> +    }
>> +}
>>
>>  struct linux_target_ops the_low_target = {
>>   init_registers_i386_linux,
>> @@ -201,10 +349,12 @@ struct linux_target_ops the_low_target =
>>   NULL,
>>   1,
>>   i386_breakpoint_at,
>> +  i386_insert_watchpoint,
>> +  i386_remove_watchpoint,
>> +  i386_stopped_by_watchpoint,
>> +  i386_stopped_data_address,
>>   NULL,
>>   NULL,
>> -  NULL,
>> -  NULL,
>> -  NULL,
>> -  NULL,
>> +  i386_linux_new_process,
>> +  i386_linux_new_thread
>>  };
>> Index: linux-low.c
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/gdbserver/linux-low.c,v
>> retrieving revision 1.97
>> diff -u -p -r1.97 linux-low.c
>> --- linux-low.c 3 Apr 2009 11:40:02 -0000       1.97
>> +++ linux-low.c 30 Apr 2009 06:26:54 -0000
>> @@ -120,6 +120,7 @@ static int must_set_ptrace_flags;
>>    control of gdbserver have the same architecture.  */
>>  static int new_inferior;
>>
>> +static void notify_low_target_new_thread (struct lwp_info *lwp, int initial);
>>  static void linux_resume_one_lwp (struct inferior_list_entry *entry,
>>                                  int step, int signal, siginfo_t *info);
>>  static void linux_resume (struct thread_resume *resume_info, size_t n);
>> @@ -179,6 +180,9 @@ 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);
>> +
>>   return proc;
>>  }
>>
>> @@ -188,6 +192,7 @@ 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);
>>  }
>> @@ -231,6 +236,7 @@ handle_extended_wait (struct lwp_info *e
>>       ptid = ptid_build (pid_of (event_child), new_pid, 0);
>>       new_lwp = (struct lwp_info *) add_lwp (ptid);
>>       add_thread (ptid, new_lwp);
>> +      notify_low_target_new_thread (new_lwp, 0);
>>
>>       /* Normally we will get the pending SIGSTOP.  But in some cases
>>         we might get another signal delivered to the group first.
>> @@ -313,6 +319,18 @@ add_lwp (ptid_t ptid)
>>   return lwp;
>>  }
>>
>> +/* Notify the backend that we have a new thread, be it the main thread
>> +   or a later one.
>> +   INITIAL is non-zero for the main thread, zero otherwise.
>> +   NOTE: This must be called when the thread is stopped.  */
>> +
>> +static void
>> +notify_low_target_new_thread (struct lwp_info *lwp, int initial)
>> +{
>> +  if (the_low_target.new_thread != NULL)
>> +    the_low_target.new_thread (lwp, initial);
>> +}
>> +
>>  /* Start an inferior process and returns its pid.
>>    ALLARGS is a vector of program-name and args. */
>>
>> @@ -354,6 +372,8 @@ linux_create_inferior (char *program, ch
>>   ptid = ptid_build (pid, pid, 0);
>>   new_lwp = add_lwp (ptid);
>>   add_thread (ptid, new_lwp);
>> +  /* We can't call notify_low_target_new_thread there, the thread isn't
>> +     stopped.  Piggyback on must_set_ptrace_flags and call it then.  */
>>   must_set_ptrace_flags = 1;
>>
>>   return pid;
>> @@ -401,6 +421,7 @@ linux_attach_lwp_1 (unsigned long lwpid,
>>
>>   new_lwp = (struct lwp_info *) add_lwp (ptid);
>>   add_thread (ptid, new_lwp);
>> +  notify_low_target_new_thread (new_lwp, initial);
>>
>>   /* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH
>>      brings it to a halt.
>> @@ -1261,6 +1282,7 @@ retry:
>>   if (must_set_ptrace_flags)
>>     {
>>       ptrace (PTRACE_SETOPTIONS, lwpid_of (lwp), 0, PTRACE_O_TRACECLONE);
>> +      notify_low_target_new_thread (lwp, 1);
>>       must_set_ptrace_flags = 0;
>>     }
>>   /* If we are waiting for a particular child, and it exited,
>> @@ -2599,7 +2623,11 @@ static int
>>  linux_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);
>> +    {
>> +      struct process_info *proc = current_process ();
>> +      return the_low_target.insert_watchpoint (proc->private->arch_private,
>> +                                              type, addr, len);
>> +    }
>>   else
>>     /* Unsupported (see target.h).  */
>>     return 1;
>> @@ -2609,7 +2637,11 @@ static int
>>  linux_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);
>> +    {
>> +      struct process_info *proc = current_process ();
>> +      return the_low_target.remove_watchpoint (proc->private->arch_private,
>> +                                              type, addr, len);
>> +    }
>>   else
>>     /* Unsupported (see target.h).  */
>>     return 1;
>> @@ -2619,7 +2651,10 @@ static int
>>  linux_stopped_by_watchpoint (void)
>>  {
>>   if (the_low_target.stopped_by_watchpoint != NULL)
>> -    return the_low_target.stopped_by_watchpoint ();
>> +    {
>> +      struct process_info *proc = current_process ();
>> +      return the_low_target.stopped_by_watchpoint (proc->private->arch_private);
>> +    }
>>   else
>>     return 0;
>>  }
>> @@ -2628,7 +2663,10 @@ static CORE_ADDR
>>  linux_stopped_data_address (void)
>>  {
>>   if (the_low_target.stopped_data_address != NULL)
>> -    return the_low_target.stopped_data_address ();
>> +    {
>> +      struct process_info *proc = current_process ();
>> +      return the_low_target.stopped_data_address (proc->private->arch_private);
>> +    }
>>   else
>>     return 0;
>>  }
>> Index: linux-low.h
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/gdbserver/linux-low.h,v
>> retrieving revision 1.28
>> diff -u -p -r1.28 linux-low.h
>> --- linux-low.h 1 Apr 2009 22:50:24 -0000       1.28
>> +++ linux-low.h 30 Apr 2009 01:23:29 -0000
>> @@ -54,8 +54,13 @@ 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.  */
>> @@ -75,26 +80,37 @@ struct linux_target_ops
>>   int breakpoint_len;
>>   CORE_ADDR (*breakpoint_reinsert_addr) (void);
>>
>> -
>>   int decr_pc_after_break;
>>   int (*breakpoint_at) (CORE_ADDR pc);
>>
>>   /* 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);
>> +  int (*insert_watchpoint) (struct arch_process_info *arch_private,
>> +                           char type, CORE_ADDR addr, int len);
>> +  int (*remove_watchpoint) (struct arch_process_info *arch_private,
>> +                           char type, CORE_ADDR addr, int len);
>> +  int (*stopped_by_watchpoint) (struct arch_process_info *arch_private);
>> +  CORE_ADDR (*stopped_data_address) (struct arch_process_info *arch_private);
>>
>>   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
>>      for registers smaller than an xfer unit).  */
>>   void (*collect_ptrace_register) (int regno, char *buf);
>>   void (*supply_ptrace_register) (int regno, const char *buf);
>> +
>> +  /* Hook to call when a new process is created or attached to.  */
>> +  struct arch_process_info * (*new_process) (int pid, int attached);
>> +
>> +  /* Hook to call when a new thread is detected.
>> +     INITIAL is non-zero for the main thread, zero otherwise.  */
>> +  void (*new_thread) (struct lwp_info *, int initial);
>>  };
>>
>>  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)
>> +#define PIDGET(ptid) ptid_get_pid (ptid)
>> +#define TIDGET(ptid) ptid_get_lwp (ptid)
>>
>>  #define get_lwp(inf) ((struct lwp_info *)(inf))
>>  #define get_thread_lwp(thr) (get_lwp (inferior_target_data (thr)))
>> Index: linux-x86-64-low.c
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/gdbserver/linux-x86-64-low.c,v
>> retrieving revision 1.22
>> diff -u -p -r1.22 linux-x86-64-low.c
>> --- linux-x86-64-low.c  22 Mar 2009 23:57:10 -0000      1.22
>> +++ linux-x86-64-low.c  30 Apr 2009 01:23:29 -0000
>> @@ -18,9 +18,11 @@
>>    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 "server.h"
>>  #include "linux-low.h"
>>  #include "i387-fp.h"
>> +#include "i386-low.h"
>>
>>  #include "gdb_proc_service.h"
>>
>> @@ -45,6 +47,11 @@ void init_registers_x86_64_linux (void);
>>  #define ARCH_GET_GS 0x1004
>>  #endif
>>
>> +struct arch_process_info
>> +{
>> +  struct i386_debug_reg_state debug_reg_state;
>> +};
>> +
>>  static int x86_64_regmap[] = {
>>   RAX * 8, RBX * 8, RCX * 8, RDX * 8,
>>   RSI * 8, RDI * 8, RBP * 8, RSP * 8,
>> @@ -161,6 +168,148 @@ x86_64_breakpoint_at (CORE_ADDR pc)
>>
>>   return 0;
>>  }
>> +
>> +/* Support for debug registers.  */
>> +
>> +static unsigned long
>> +x86_64_linux_dr_get (ptid_t ptid, int regnum)
>> +{
>> +  int tid;
>> +  unsigned long value;
>> +
>> +  tid = TIDGET (ptid);
>> +  if (tid == 0)
>> +    tid = PIDGET (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_64_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
>> +{
>> +  int tid;
>> +
>> +  tid = TIDGET (ptid);
>> +  if (tid == 0)
>> +    tid = PIDGET (ptid);
>> +
>> +  errno = 0;
>> +  ptrace (PTRACE_POKEUSER, tid,
>> +         offsetof (struct user, u_debugreg[regnum]), value);
>> +  if (errno != 0)
>> +    error ("Couldn't write debug register");
>> +}
>> +
>> +/* Pass the address ADDR to the inferior in debug register REGNUM.  */
>> +
>> +void
>> +i386_dr_low_set_addr (int regnum, CORE_ADDR addr)
>> +{
>> +  struct inferior_list_entry *lp;
>> +
>> +  if (! (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR))
>> +    error ("Invalid debug register");
>> +
>> +  for (lp = all_lwps.head; lp; lp = lp->next)
>> +    {
>> +      struct lwp_info *lwp = (struct lwp_info *) lp;
>> +      x86_64_linux_dr_set (ptid_of (lwp), DR_FIRSTADDR + regnum, addr);
>> +    }
>> +}
>> +
>> +/* Pass the value VAL to the inferior in the DR7 debug control register.  */
>> +
>> +void
>> +i386_dr_low_set_control (unsigned control)
>> +{
>> +  struct inferior_list_entry *lp;
>> +
>> +  for (lp = all_lwps.head; lp; lp = lp->next)
>> +    {
>> +      struct lwp_info *lwp = (struct lwp_info *) lp;
>> +      x86_64_linux_dr_set (ptid_of (lwp), DR_CONTROL, control);
>> +    }
>> +}
>> +
>> +/* Get the value of the DR6 debug status register from the inferior.  */
>> +
>> +unsigned
>> +i386_dr_low_get_status (void)
>> +{
>> +  ptid_t inferior_ptid = ptid_of (get_thread_lwp (current_inferior));
>> +  return x86_64_linux_dr_get (inferior_ptid, DR_STATUS);
>> +}
>> +
>> +/* Watchpoint support.  */
>> +
>> +static int
>> +x86_64_insert_watchpoint (struct arch_process_info *arch_private,
>> +                         char type, CORE_ADDR addr, int len)
>> +{
>> +  return i386_low_insert_watchpoint (&arch_private->debug_reg_state,
>> +                                    type, addr, len);
>> +}
>> +
>> +static int
>> +x86_64_remove_watchpoint (struct arch_process_info *arch_private,
>> +                         char type, CORE_ADDR addr, int len)
>> +{
>> +  return i386_low_remove_watchpoint (&arch_private->debug_reg_state,
>> +                                    type, addr, len);
>> +}
>> +
>> +static int
>> +x86_64_stopped_by_watchpoint (struct arch_process_info *arch_private)
>> +{
>> +  return i386_low_stopped_by_watchpoint (&arch_private->debug_reg_state);
>> +}
>> +
>> +static CORE_ADDR
>> +x86_64_stopped_data_address (struct arch_process_info *arch_private)
>> +{
>> +  return i386_low_stopped_data_address (&arch_private->debug_reg_state);
>> +}
>> +
>> +/* Called when a new process is created.  */
>> +
>> +struct arch_process_info *
>> +x86_64_linux_new_process (int pid, int attached)
>> +{
>> +  struct arch_process_info *info = xcalloc (1, sizeof (*info));
>> +
>> +  return info;
>> +}
>> +
>> +/* Called when a new thread is detected.
>> +   INITIAL is non-zero for the main thread, zero otherwise.  */
>> +
>> +static void
>> +x86_64_linux_new_thread (struct lwp_info *lwp, int initial)
>> +{
>> +  /* The initial thread has debug regs set later during process
>> +     creation/attaching handling.  */
>> +
>> +  if (! initial)
>> +    {
>> +      int i;
>> +      ptid_t ptid = ptid_of (lwp);
>> +      int pid = PIDGET (ptid);
>> +      struct process_info *proc = find_process_pid (pid);
>> +      struct arch_process_info *arch_private = proc->private->arch_private;
>> +      struct i386_debug_reg_state *state = &arch_private->debug_reg_state;
>> +
>> +      for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
>> +       x86_64_linux_dr_set (ptid, i, state->dr_mirror[i]);
>> +
>> +      x86_64_linux_dr_set (ptid, DR_CONTROL, state->dr_control_mirror);
>> +    }
>> +}
>>
>>  struct linux_target_ops the_low_target = {
>>   init_registers_x86_64_linux,
>> @@ -175,10 +324,12 @@ struct linux_target_ops the_low_target =
>>   NULL,
>>   1,
>>   x86_64_breakpoint_at,
>> +  x86_64_insert_watchpoint,
>> +  x86_64_remove_watchpoint,
>> +  x86_64_stopped_by_watchpoint,
>> +  x86_64_stopped_data_address,
>>   NULL,
>>   NULL,
>> -  NULL,
>> -  NULL,
>> -  NULL,
>> -  NULL,
>> +  x86_64_linux_new_process,
>> +  x86_64_linux_new_thread
>>  };
>> Index: server.h
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/gdbserver/server.h,v
>> retrieving revision 1.56
>> diff -u -p -r1.56 server.h
>> --- server.h    3 Apr 2009 20:15:51 -0000       1.56
>> +++ server.h    30 Apr 2009 01:23:29 -0000
>> @@ -405,6 +405,7 @@ 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     30 Apr 2009 01:23:29 -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     30 Apr 2009 01:23:29 -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    30 Apr 2009 01:23:29 -0000
>> @@ -17,6 +17,7 @@
>>
>>  #include "server.h"
>>  #include "win32-low.h"
>> +#include "i386-low.h"
>>
>>  #define FCS_REGNUM 27
>>  #define FOP_REGNUM 31
>> @@ -31,6 +32,42 @@ static unsigned dr[8];
>>  static int debug_registers_changed = 0;
>>  static int debug_registers_used = 0;
>>
>> +/* Pass the address ADDR to the inferior in the I'th debug register.
>> +   Here we just store the address in dr array, the registers will be
>> +   actually set up when windows_continue is called.  */
>> +
>> +void
>> +i386_dr_low_set_addr (int i, CORE_ADDR addr)
>> +{
>> +  if (i < 0 || i > 3)
>> +   return;
>> +  dr[i] = (unsigned) addr;
>> +  debug_registers_changed = 1;
>> +  debug_registers_used = 1;
>> +}
>> +
>> +/* Pass the value VAL to the inferior in the DR7 debug control register.
>> +   Here we just store the address in D_REGS, the watchpoint
>> +   will be actually set up in windows_wait.  */
>> +
>> +void
>> +i386_dr_low_set_control (unsigned val)
>> +{
>> +  dr[7] = val;
>> +  debug_registers_changed = 1;
>> +  debug_registers_used = 1;
>> +}
>> +
>> +/* Get the value of the DR6 debug status register from the inferior.
>> +   Here we just return the value stored in dr[6]
>> +   by the last call to thread_rec for current_event.dwThreadId id.  */
>> +
>> +unsigned
>> +i386_dr_low_get_status (void)
>> +{
>> +  return dr[6];
>> +}
>> +
>>  static void
>>  i386_initial_stuff (void)
>>  {
>> @@ -205,4 +242,8 @@ 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 1.35
>> diff -u -p -r1.35 win32-low.c
>> --- win32-low.c 1 Apr 2009 22:50:24 -0000       1.35
>> +++ win32-low.c 30 Apr 2009 01:23:29 -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 30 Apr 2009 01:23:29 -0000
>> @@ -70,6 +70,13 @@ 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;
>>
>