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

Doug Evans
2009-06-02T15:36:34Z

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On Tue, May 19, 2009 at 2:05 AM, Pierre Muller <muller@ics.u-strasbg.fr> wrote:
>  Doug, I think that your should send a new RFA
> for an up-to-date patch with the bi-arch stuff.
> Do we have an automated testsuite result comparison script
> that can be used for gdbserver testing?

I just use --target_board=native-gdbserver.exp and compare before/after.
ref: http://sourceware.org/gdb/wiki/Native_gdbserver_testing

No regressions on amd64 gdbserver, 32-bit and 64-bit.

>  I can test compilation on cygwin,
> but testing can only be done manually...

Thanks, can you give this a try?

>  Hopefully, Pedro will then be able to review it rapidly.

There's one aspect of this patch that one might want changing.
[I'd like to see the change, fwiw.]

It's ok for higher level routines to refer to global state (within
reason), but it's less ok for lower level routines to refer to global
state (modulo constant tables and such that won't change for the
duration). The higher level routines should pass down context so the
lower level routines don't refer to any global state (again, within
reason).

Applying that principle here means routines in linux-x86-low.c, for
example, should not refer to any global state.
Shall I add parameters to insert_watchpoint, etc. so that, for
example, x86_insert_watchpoint doesn't have to call current_process?

Pedro: Note that this patch does defer updating the debug regs until
just before PTRACE_CONT.
[win32 version already did a similar thing]

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2009-06-01 Doug Evans <dje@google.com>
Pierre Muller <muller@ics.u-strasbg.fr>

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

Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/Makefile.in,v
retrieving revision 1.74
diff -u -p -r1.74 Makefile.in
--- Makefile.in 12 May 2009 22:25:00 -0000 1.74
+++ Makefile.in 1 Jun 2009 22:02:43 -0000
@@ -104,7 +104,7 @@ SFILES= $(srcdir)/gdbreplay.c $(srcdir)/
$(srcdir)/thread-db.c $(srcdir)/utils.c \
$(srcdir)/linux-arm-low.c $(srcdir)/linux-cris-low.c \
$(srcdir)/linux-crisv32-low.c \
- $(srcdir)/i387-fp.c \
+ ${srcdir}/i386-low.c $(srcdir)/i387-fp.c \
$(srcdir)/linux-ia64-low.c $(srcdir)/linux-low.c \
$(srcdir)/linux-m32r-low.c \
$(srcdir)/linux-m68k-low.c $(srcdir)/linux-mips-low.c \
@@ -287,6 +287,10 @@ signals.o: ../common/signals.c $(server_
memmem.o: ../gnulib/memmem.c
$(CC) -o memmem.o -c $(CPPFLAGS) $(INTERNAL_CFLAGS) $<

+i386_low_h = $(srcdir)/i386-low.h
+
+i386-low.o: i386-low.c $(i386_low_h) $(server_h) $(target_h)
+
i387-fp.o: i387-fp.c $(server_h)

linux-low.o: linux-low.c $(linux_low_h) $(server_h)
@@ -304,7 +308,7 @@ linux-ppc-low.o: linux-ppc-low.c $(linux
linux-s390-low.o: linux-s390-low.c $(linux_low_h) $(server_h)
linux-sh-low.o: linux-sh-low.c $(linux_low_h) $(server_h)
linux-x86-low.o: linux-x86-low.c $(linux_low_h) $(server_h) \
- $(gdb_proc_service_h)
+ $(gdb_proc_service_h) $(i386_low_h)
linux-xtensa-low.o: linux-xtensa-low.c xtensa-xtregs.c $(linux_low_h) $(server_h)

win32_low_h = $(srcdir)/win32-low.h
@@ -312,7 +316,7 @@ win32_low_h = $(srcdir)/win32-low.h
win32-low.o: win32-low.c $(win32_low_h) $(server_h) $(regdef_h) $(regcache_h)

win32-arm-low.o: win32-arm-low.c $(win32_low_h) $(server_h)
-win32-i386-low.o: win32-i386-low.c $(win32_low_h) $(server_h)
+win32-i386-low.o: win32-i386-low.c $(win32_low_h) $(server_h) $(i386_low_h)

spu-low.o: spu-low.c $(server_h)

Index: configure.srv
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/configure.srv,v
retrieving revision 1.41
diff -u -p -r1.41 configure.srv
--- configure.srv 12 May 2009 22:25:00 -0000 1.41
+++ configure.srv 1 Jun 2009 22:02:43 -0000
@@ -53,10 +53,10 @@ case "${target}" in
srv_linux_thread_db=yes
;;
i[34567]86-*-cygwin*) srv_regobj=reg-i386.o
- srv_tgtobj="win32-low.o win32-i386-low.o"
+ srv_tgtobj="i386-low.o win32-low.o win32-i386-low.o"
;;
i[34567]86-*-linux*) srv_regobj=reg-i386-linux.o
- srv_tgtobj="linux-low.o linux-x86-low.o i387-fp.o"
+ srv_tgtobj="linux-low.o linux-x86-low.o i386-low.o i387-fp.o"
srv_linux_usrregs=yes
srv_linux_regsets=yes
srv_linux_thread_db=yes
@@ -71,7 +71,7 @@ case "${target}" in
srv_mingwce=yes
;;
i[34567]86-*-mingw*) srv_regobj=reg-i386.o
- srv_tgtobj="win32-low.o win32-i386-low.o"
+ srv_tgtobj="i386-low.o win32-low.o win32-i386-low.o"
srv_mingw=yes
;;
ia64-*-linux*) srv_regobj=reg-ia64.o
@@ -170,7 +170,7 @@ case "${target}" in
srv_tgtobj="spu-low.o"
;;
x86_64-*-linux*) srv_regobj="reg-x86-64-linux.o reg-i386-linux.o"
- srv_tgtobj="linux-low.o linux-x86-low.o i387-fp.o"
+ srv_tgtobj="linux-low.o linux-x86-low.o i386-low.o i387-fp.o"
srv_linux_usrregs=yes # This is for i386 progs.
srv_linux_regsets=yes
srv_linux_thread_db=yes
Index: i386-low.c
===================================================================
RCS file: i386-low.c
diff -N i386-low.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ i386-low.c 1 Jun 2009 22:02:43 -0000
@@ -0,0 +1,660 @@
+/* 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 fatal. */
+static int i386_handle_nonaligned_watchpoint (struct i386_debug_reg_state *state,
+ i386_wp_op_t what,
+ CORE_ADDR addr, int len,
+ enum target_hw_bp_type type);
+\f
+/* 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 (state, i);
+ i386_dr_low_set_control (state);
+
+ return 0;
+}
+
+/* Remove a watchpoint at address ADDR, which is assumed to be aligned
+ according to the length of the region to watch. LEN_RW_BITS is the
+ value of the bits from DR7 which describes the length and access
+ type of the region watched by this watchpoint. Return 0 on
+ success, -1 on failure. */
+
+static int
+i386_remove_aligned_watchpoint (struct i386_debug_reg_state *state,
+ CORE_ADDR addr, unsigned len_rw_bits)
+{
+ int i, retval = -1;
+
+ ALL_DEBUG_REGISTERS(i)
+ {
+ if (!I386_DR_VACANT (state, i)
+ && state->dr_mirror[i] == addr
+ && I386_DR_GET_RW_LEN (state, i) == len_rw_bits)
+ {
+ if (--state->dr_ref_count[i] == 0) /* no longer in use? */
+ {
+ /* Reset our mirror. */
+ state->dr_mirror[i] = 0;
+ I386_DR_DISABLE (state, i);
+ /* Reset it in the inferior. */
+ i386_dr_low_set_control (state);
+ i386_dr_low_set_addr (state, i);
+ }
+ retval = 0;
+ }
+ }
+
+ return retval;
+}
+
+/* Insert or remove a (possibly non-aligned) watchpoint, or count the
+ number of debug registers required to watch a region at address
+ ADDR whose length is LEN for accesses of type TYPE. Return 0 on
+ successful insertion or removal, a positive number when queried
+ about the number of registers, or -1 on failure. If WHAT is not a
+ valid value, bombs through internal_error. */
+
+static int
+i386_handle_nonaligned_watchpoint (struct i386_debug_reg_state *state,
+ i386_wp_op_t what, CORE_ADDR addr, int len,
+ enum target_hw_bp_type type)
+{
+ int retval = 0, status = 0;
+ int max_wp_len = TARGET_HAS_DR_LEN_8 ? 8 : 4;
+
+ static const int size_try_array[8][8] =
+ {
+ {1, 1, 1, 1, 1, 1, 1, 1}, /* Trying size one. */
+ {2, 1, 2, 1, 2, 1, 2, 1}, /* Trying size two. */
+ {2, 1, 2, 1, 2, 1, 2, 1}, /* Trying size three. */
+ {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size four. */
+ {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size five. */
+ {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size six. */
+ {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size seven. */
+ {8, 1, 2, 1, 4, 1, 2, 1}, /* Trying size eight. */
+ };
+
+ while (len > 0)
+ {
+ int align = addr % max_wp_len;
+ /* Four (eight on AMD64) is the maximum length a debug register
+ can watch. */
+ int try = (len > max_wp_len ? (max_wp_len - 1) : len - 1);
+ int size = size_try_array[try][align];
+
+ if (what == WP_COUNT)
+ {
+ /* size_try_array[] is defined such that each iteration
+ through the loop is guaranteed to produce an address and a
+ size that can be watched with a single debug register.
+ Thus, for counting the registers required to watch a
+ region, we simply need to increment the count on each
+ iteration. */
+ retval++;
+ }
+ else
+ {
+ unsigned len_rw = i386_length_and_rw_bits (size, type);
+
+ if (what == WP_INSERT)
+ status = i386_insert_aligned_watchpoint (state, addr, len_rw);
+ else if (what == WP_REMOVE)
+ status = i386_remove_aligned_watchpoint (state, addr, len_rw);
+ else
+ fatal ("\
+Invalid value %d of operation in i386_handle_nonaligned_watchpoint.\n",
+ (int) what);
+
+ /* We keep the loop going even after a failure, because some
+ of the other aligned watchpoints might still succeed
+ (e.g. if they watch addresses that are already watched,
+ in which case we just increment the reference counts of
+ occupied debug registers). If we break out of the loop
+ too early, we could cause those addresses watched by
+ other watchpoints to be disabled when breakpoint.c reacts
+ to our failure to insert this watchpoint and tries to
+ remove it. */
+ if (status)
+ retval = status;
+ }
+
+ addr += size;
+ len -= size;
+ }
+
+ return retval;
+}
+
+#define Z_PACKET_WRITE_WP '2'
+#define Z_PACKET_READ_WP '3'
+#define Z_PACKET_ACCESS_WP '4'
+
+static int
+Z_packet_to_hw_type (char type)
+{
+ switch (type)
+ {
+ case Z_PACKET_WRITE_WP: return hw_write;
+ case Z_PACKET_READ_WP: return hw_read;
+ case Z_PACKET_ACCESS_WP: return hw_access;
+ default:
+ error ("Z_packet_to_hw_type: bad watchpoint type %c", type);
+ }
+}
+
+/* Insert a watchpoint to watch a memory region which starts at
+ address ADDR and whose length is LEN bytes. Watch memory accesses
+ of the type TYPE_FROM_PACKET. Return 0 on success, -1 on failure. */
+
+int
+i386_low_insert_watchpoint (struct i386_debug_reg_state *state,
+ char type_from_packet, CORE_ADDR addr, int len)
+{
+ int retval;
+ int type = Z_packet_to_hw_type (type_from_packet);
+
+ if (((len != 1 && len !=2 && len !=4) && !(TARGET_HAS_DR_LEN_8 && len == 8))
+ || addr % len != 0)
+ {
+ retval = i386_handle_nonaligned_watchpoint (state, WP_INSERT,
+ addr, len, type);
+ }
+ else
+ {
+ unsigned len_rw = i386_length_and_rw_bits (len, type);
+
+ retval = i386_insert_aligned_watchpoint (state, addr, len_rw);
+ }
+
+ if (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;
+
+ /* Get dr_status_mirror for use by I386_DR_WATCH_HIT. */
+ i386_dr_low_get_status (state);
+
+ ALL_DEBUG_REGISTERS(i)
+ {
+ if (I386_DR_WATCH_HIT (state, i)
+ /* This second condition makes sure DRi is set up for a data
+ watchpoint, not a hardware breakpoint. The reason is
+ that GDB doesn't call the target_stopped_data_address
+ method except for data watchpoints. In other words, I'm
+ being paranoiac. */
+ && I386_DR_GET_RW_LEN (state, i) != 0)
+ {
+ addr = state->dr_mirror[i];
+ if (maint_show_dr)
+ i386_show_dr (state, "watchpoint_hit", addr, -1, hw_write);
+ }
+ }
+
+ if (maint_show_dr && addr == 0)
+ i386_show_dr (state, "stopped_data_addr", 0, 0, hw_write);
+
+ /* NOTE: gdb version checks rc != 0 here. */
+ return addr;
+}
+
+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);
+}
+\f
+/* 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;
+
+ /* Get dr_status_mirror for use by I386_DR_WATCH_HIT. */
+ i386_dr_low_get_status (state);
+
+ 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 1 Jun 2009 22:02:43 -0000
@@ -0,0 +1,120 @@
+/* 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);
+\f
+/* Each target needs to provide several low-level functions
+ that will be called to insert watchpoints and hardware breakpoints
+ into the inferior, remove them, and check their status. These
+ functions are:
+
+ i386_dr_low_set_control -- set the debug control (DR7)
+ register to a given value
+
+ i386_dr_low_set_addr -- put an address into one debug register
+
+ i386_dr_low_get_status -- return the value of the debug
+ status (DR6) register.
+*/
+
+/* Update the inferior's debug register REGNUM from STATE. */
+extern void i386_dr_low_set_addr (const struct i386_debug_reg_state *state,
+ int regnum);
+
+/* Update the inferior's DR7 debug control register from STATE. */
+extern void i386_dr_low_set_control (const struct i386_debug_reg_state *state);
+
+/* Get the value of the inferior's DR6 debug status register
+ and record it in STATE. */
+extern void i386_dr_low_get_status (struct i386_debug_reg_state *state);
Index: linux-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/linux-low.c,v
retrieving revision 1.105
diff -u -p -r1.105 linux-low.c
--- linux-low.c 24 May 2009 17:44:19 -0000 1.105
+++ linux-low.c 1 Jun 2009 22:02:43 -0000
@@ -224,6 +224,7 @@ delete_lwp (struct lwp_info *lwp)
{
remove_thread (get_lwp_thread (lwp));
remove_inferior (&all_lwps, &lwp->head);
+ free (lwp->arch_private);
free (lwp);
}

@@ -242,6 +243,9 @@ linux_add_process (int pid, int attached
proc = add_process (pid, attached);
proc->private = xcalloc (1, sizeof (*proc->private));

+ if (the_low_target.new_process != NULL)
+ proc->private->arch_private = the_low_target.new_process (pid, attached);
+
return proc;
}

@@ -251,6 +255,7 @@ linux_add_process (int pid, int attached
static void
linux_remove_process (struct process_info *process)
{
+ free (process->private->arch_private);
free (process->private);
remove_process (process);
}
@@ -376,6 +381,9 @@ add_lwp (ptid_t ptid)

lwp->head.id = ptid;

+ if (the_low_target.new_thread != NULL)
+ lwp->arch_private = the_low_target.new_thread (ptid);
+
add_inferior_to_list (&all_lwps, &lwp->head);

return lwp;
@@ -466,7 +474,6 @@ linux_attach_lwp_1 (unsigned long lwpid,
new_lwp = (struct lwp_info *) add_lwp (ptid);
add_thread (ptid, new_lwp);

-
/* We need to wait for SIGSTOP before being able to make the next
ptrace call on this LWP. */
new_lwp->must_set_ptrace_flags = 1;
@@ -1740,6 +1747,9 @@ linux_resume_one_lwp (struct lwp_info *l
*p_sig = NULL;
}

+ if (the_low_target.prepare_to_resume != NULL)
+ the_low_target.prepare_to_resume (lwp);
+
regcache_invalidate_one ((struct inferior_list_entry *)
get_lwp_thread (lwp));
errno = 0;
Index: linux-low.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/linux-low.h,v
retrieving revision 1.30
diff -u -p -r1.30 linux-low.h
--- linux-low.h 12 May 2009 22:25:00 -0000 1.30
+++ linux-low.h 1 Jun 2009 22:02:43 -0000
@@ -56,8 +56,13 @@ struct process_info_private

/* Connection to the libthread_db library. */
td_thragent_t *thread_agent;
+
+ /* Target-specific additions. */
+ struct arch_process_info *arch_private;
};

+struct lwp_info;
+
struct linux_target_ops
{
/* Architecture-specific setup. */
@@ -96,12 +101,28 @@ struct linux_target_ops
If DIRECTION is 1, then copy from INF to NATIVE.
If DIRECTION is 0, copy from NATIVE to INF. */
int (*siginfo_fixup) (struct siginfo *native, void *inf, int direction);
+
+ /* Hook to call when a new process is created or attached to.
+ If the target needs per-process architecture-specific data,
+ allocate it here. */
+ struct arch_process_info * (*new_process) (int pid, int attached);
+
+ /* Hook to call when a new thread is detected.
+ If the target needs per-thread architecture-specific data,
+ allocate it here. */
+ struct arch_lwp_info * (*new_thread) (ptid_t ptid);
+
+ /* Hook to call prior to resuming a thread. */
+ void (*prepare_to_resume) (struct lwp_info *);
};

extern struct linux_target_ops the_low_target;

+#define ptid_of(proc) ((proc)->head.id)
#define pid_of(proc) ptid_get_pid ((proc)->head.id)
#define lwpid_of(proc) ptid_get_lwp ((proc)->head.id)
+#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)))
@@ -172,6 +193,9 @@ struct lwp_info
THREAD_KNOWN is set. */
td_thrhandle_t th;
#endif
+
+ /* Target-specific additions. */
+ struct arch_lwp_info *arch_private;
};

extern struct inferior_list all_lwps;
Index: linux-x86-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/linux-x86-low.c,v
retrieving revision 1.2
diff -u -p -r1.2 linux-x86-low.c
--- linux-x86-low.c 13 May 2009 19:11:04 -0000 1.2
+++ linux-x86-low.c 1 Jun 2009 22:02:43 -0000
@@ -18,10 +18,12 @@
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */

+#include <stddef.h>
#include <signal.h>
#include "server.h"
#include "linux-low.h"
#include "i387-fp.h"
+#include "i386-low.h"

#include "gdb_proc_service.h"

@@ -56,6 +58,21 @@ void init_registers_x86_64_linux (void);
#define ARCH_GET_GS 0x1004
#endif

+/* Per-process arch-specific data we want to keep. */
+
+struct arch_process_info
+{
+ struct i386_debug_reg_state debug_reg_state;
+};
+
+/* Per-thread arch-specific data we want to keep. */
+
+struct arch_lwp_info
+{
+ /* Non-zero if our copy differs from what's recorded in the thread. */
+ int debug_registers_changed;
+};
+
#ifdef __x86_64__

/* Mapping between the general-purpose registers in `struct user'
@@ -317,6 +334,174 @@ x86_breakpoint_at (CORE_ADDR pc)
return 0;
}
\f
+/* Support for debug registers. */
+
+static unsigned long
+x86_linux_dr_get (ptid_t ptid, int regnum)
+{
+ int tid;
+ unsigned long value;
+
+ tid = 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_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");
+}
+
+/* Update the inferior's debug register REGNUM from STATE. */
+
+void
+i386_dr_low_set_addr (const struct i386_debug_reg_state *state, int regnum)
+{
+ struct inferior_list_entry *lp;
+ CORE_ADDR addr;
+
+ if (! (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR))
+ fatal ("Invalid debug register %d", regnum);
+
+ addr = state->dr_mirror[regnum];
+
+ /* ??? Will need tweaking for multi-process. */
+ for (lp = all_lwps.head; lp; lp = lp->next)
+ {
+ struct lwp_info *lwp = (struct lwp_info *) lp;
+
+ /* The actual update is done later, we just mark that the register
+ needs updating. */
+ lwp->arch_private->debug_registers_changed = 1;
+ }
+}
+
+/* Update the inferior's DR7 debug control register from STATE. */
+
+void
+i386_dr_low_set_control (const struct i386_debug_reg_state *state)
+{
+ struct inferior_list_entry *lp;
+
+ /* ??? Will need tweaking for multi-process. */
+ for (lp = all_lwps.head; lp; lp = lp->next)
+ {
+ struct lwp_info *lwp = (struct lwp_info *) lp;
+
+ /* The actual update is done later, we just mark that the register
+ needs updating. */
+ lwp->arch_private->debug_registers_changed = 1;
+ }
+}
+
+/* Get the value of the DR6 debug status register from the inferior
+ and record it in STATE. */
+
+void
+i386_dr_low_get_status (struct i386_debug_reg_state *state)
+{
+ struct lwp_info *lwp = get_thread_lwp (current_inferior);
+ ptid_t ptid = ptid_of (lwp);
+
+ state->dr_status_mirror = x86_linux_dr_get (ptid, DR_STATUS);
+}
+\f
+/* Watchpoint support. */
+
+static int
+x86_insert_watchpoint (char type, CORE_ADDR addr, int len)
+{
+ struct process_info *proc = current_process ();
+ return i386_low_insert_watchpoint (&proc->private->arch_private->debug_reg_state,
+ type, addr, len);
+}
+
+static int
+x86_remove_watchpoint (char type, CORE_ADDR addr, int len)
+{
+ struct process_info *proc = current_process ();
+ return i386_low_remove_watchpoint (&proc->private->arch_private->debug_reg_state,
+ type, addr, len);
+}
+
+static int
+x86_stopped_by_watchpoint (void)
+{
+ struct process_info *proc = current_process ();
+ return i386_low_stopped_by_watchpoint (&proc->private->arch_private->debug_reg_state);
+}
+
+static CORE_ADDR
+x86_stopped_data_address (void)
+{
+ struct process_info *proc = current_process ();
+ return i386_low_stopped_data_address (&proc->private->arch_private->debug_reg_state);
+}
+\f
+/* Called when a new process is created. */
+
+struct arch_process_info *
+x86_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. */
+
+static struct arch_lwp_info *
+x86_linux_new_thread (ptid_t ptid)
+{
+ struct arch_lwp_info *info = xcalloc (1, sizeof (*info));
+
+ info->debug_registers_changed = 1;
+
+ return info;
+}
+
+/* Called when resuming a thread.
+ If the debug regs have changed, update the thread's copies. */
+
+static void
+x86_linux_prepare_to_resume (struct lwp_info *lwp)
+{
+ if (lwp->arch_private->debug_registers_changed)
+ {
+ int i;
+ ptid_t ptid = ptid_of (lwp);
+ int pid = ptid_get_pid (ptid);
+ struct process_info *proc = find_process_pid (pid);
+ struct i386_debug_reg_state *state = &proc->private->arch_private->debug_reg_state;
+
+ for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
+ x86_linux_dr_set (ptid, i, state->dr_mirror[i]);
+
+ x86_linux_dr_set (ptid, DR_CONTROL, state->dr_control_mirror);
+
+ lwp->arch_private->debug_registers_changed = 0;
+ }
+}
+\f
/* When GDBSERVER is built as a 64-bit application on linux, the
PTRACE_GETSIGINFO data is always presented in 64-bit layout. Since
debugging a 32-bit inferior with a 64-bit GDBSERVER should look the same
@@ -630,10 +815,10 @@ struct linux_target_ops the_low_target =
NULL,
1,
x86_breakpoint_at,
- NULL,
- NULL,
- NULL,
- NULL,
+ x86_insert_watchpoint,
+ x86_remove_watchpoint,
+ x86_stopped_by_watchpoint,
+ x86_stopped_data_address,
/* collect_ptrace_register/supply_ptrace_register are not needed in the
native i386 case (no registers smaller than an xfer unit), and are not
used in the biarch case (HAVE_LINUX_USRREGS is not defined). */
@@ -641,4 +826,7 @@ struct linux_target_ops the_low_target =
NULL,
/* need to fix up i386 siginfo if host is amd64 */
x86_siginfo_fixup,
+ x86_linux_new_process,
+ x86_linux_new_thread,
+ x86_linux_prepare_to_resume
};
Index: server.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/server.h,v
retrieving revision 1.58
diff -u -p -r1.58 server.h
--- server.h 24 May 2009 21:06:53 -0000 1.58
+++ server.h 1 Jun 2009 22:02:43 -0000
@@ -407,6 +407,7 @@ 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 1 Jun 2009 22:02:43 -0000
@@ -170,3 +170,37 @@ warning (const char *string,...)
fprintf (stderr, "\n");
va_end (args);
}
+
+/* temporary storage using circular buffer */
+#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 1 Jun 2009 22:02:43 -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 1 Jun 2009 22:02:43 -0000
@@ -17,6 +17,7 @@

#include "server.h"
#include "win32-low.h"
+#include "i386-low.h"

#define FCS_REGNUM 27
#define FOP_REGNUM 31
@@ -26,15 +27,80 @@
/* Defined in auto-generated file reg-i386.c. */
void init_registers_i386 (void);

-static unsigned dr[8];
+static struct i386_debug_reg_state debug_reg_state;

static int debug_registers_changed = 0;
static int debug_registers_used = 0;

+/* Update the inferior's debug register REGNUM from STATE. */
+
+void
+i386_dr_low_set_addr (const struct i386_debug_reg_state *state, int regnum)
+{
+ if (! (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR))
+ fatal ("Invalid debug register %d", regnum);
+
+ /* debug_reg_state.dr_mirror is already set.
+ Just notify i386_set_thread_context, i386_thread_added
+ that the registers need to be updated. */
+ debug_registers_changed = 1;
+ debug_registers_used = 1;
+}
+
+/* Update the inferior's DR7 debug control register from STATE. */
+
+void
+i386_dr_low_set_control (const struct i386_debug_reg_state *state)
+{
+ /* debug_reg_state.dr_control_mirror is already set.
+ Just notify i386_set_thread_context, i386_thread_added
+ that the registers need to be updated. */
+ debug_registers_changed = 1;
+ debug_registers_used = 1;
+}
+
+/* Get the value of the DR6 debug status register from the inferior
+ and record it in STATE. */
+
+void
+i386_dr_low_get_status (struct i386_debug_reg_state *state)
+{
+ /* We don't need to do anything here, the last call to thread_rec for
+ current_event.dwThreadId id has already set it. */
+}
+
+/* Watchpoint support. */
+
+static int
+i386_insert_watchpoint (char type, CORE_ADDR addr, int len)
+{
+ return i386_low_insert_watchpoint (&debug_reg_state,
+ type, addr, len);
+}
+
+static int
+i386_remove_watchpoint (char type, CORE_ADDR addr, int len)
+{
+ return i386_low_remove_watchpoint (&debug_reg_state,
+ type, addr, len);
+}
+
+static int
+i386_stopped_by_watchpoint (void)
+{
+ return i386_low_stopped_by_watchpoint (&debug_reg_state);
+}
+
+static CORE_ADDR
+i386_stopped_data_address (void)
+{
+ return i386_low_stopped_data_address (&debug_reg_state);
+}
+
static void
i386_initial_stuff (void)
{
- memset (&dr, 0, sizeof (dr));
+ memset (&debug_reg_state, 0, sizeof (debug_reg_state));
debug_registers_changed = 0;
debug_registers_used = 0;
}
@@ -55,12 +121,13 @@ i386_get_thread_context (win32_thread_in
if (th->tid == current_event->dwThreadId)
{
/* Copy dr values from the current thread. */
- dr[0] = th->context.Dr0;
- dr[1] = th->context.Dr1;
- dr[2] = th->context.Dr2;
- dr[3] = th->context.Dr3;
- dr[6] = th->context.Dr6;
- dr[7] = th->context.Dr7;
+ struct i386_debug_reg_state *dr = &debug_reg_state;
+ dr->dr_mirror[0] = th->context.Dr0;
+ dr->dr_mirror[1] = th->context.Dr1;
+ dr->dr_mirror[2] = th->context.Dr2;
+ dr->dr_mirror[3] = th->context.Dr3;
+ dr->dr_status_mirror = th->context.Dr6;
+ dr->dr_control_mirror = th->context.Dr7;
}
}

@@ -69,13 +136,14 @@ i386_set_thread_context (win32_thread_in
{
if (debug_registers_changed)
{
- th->context.Dr0 = dr[0];
- th->context.Dr1 = dr[1];
- th->context.Dr2 = dr[2];
- th->context.Dr3 = dr[3];
- /* th->context.Dr6 = dr[6];
+ struct i386_debug_reg_state *dr = &debug_reg_state;
+ th->context.Dr0 = dr->dr_mirror[0];
+ th->context.Dr1 = dr->dr_mirror[1];
+ th->context.Dr2 = dr->dr_mirror[2];
+ th->context.Dr3 = dr->dr_mirror[3];
+ /* th->context.Dr6 = dr->dr_status_mirror;
FIXME: should we set dr6 also ?? */
- th->context.Dr7 = dr[7];
+ th->context.Dr7 = dr->dr_control_mirror;
}

SetThreadContext (th->h, &th->context);
@@ -87,16 +155,17 @@ i386_thread_added (win32_thread_info *th
/* Set the debug registers for the new thread if they are used. */
if (debug_registers_used)
{
+ struct i386_debug_reg_state *dr = &debug_reg_state;
th->context.ContextFlags = CONTEXT_DEBUG_REGISTERS;
GetThreadContext (th->h, &th->context);

- th->context.Dr0 = dr[0];
- th->context.Dr1 = dr[1];
- th->context.Dr2 = dr[2];
- th->context.Dr3 = dr[3];
- /* th->context.Dr6 = dr[6];
+ th->context.Dr0 = dr->dr_mirror[0];
+ th->context.Dr1 = dr->dr_mirror[1];
+ th->context.Dr2 = dr->dr_mirror[2];
+ th->context.Dr3 = dr->dr_mirror[3];
+ /* th->context.Dr6 = dr->dr_status_mirror;
FIXME: should we set dr6 also ?? */
- th->context.Dr7 = dr[7];
+ th->context.Dr7 = dr->dr_control_mirror;

SetThreadContext (th->h, &th->context);
th->context.ContextFlags = 0;
@@ -205,4 +274,8 @@ 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 1 Jun 2009 22:02:43 -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 1 Jun 2009 22:02:43 -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;