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

Doug Evans dje@google.com
Thu Apr 30 07:19:00 GMT 2009


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;



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