remote watchpoint support
Mark Salter
msalter@redhat.com
Thu Jun 28 16:17:00 GMT 2001
No. There was some concern about the globals (remote_watch_data_address
and remote_stopped_by_watchpoint_p) and I never got the green light. The
globals are ugly and I think we could get rid of them with a little more
effort. I just haven't had time to pursue that.
--Mark
> Mark,
> Did you ever get a chance to check this (after fixes) in? Eli was ok
> with the doc changes and I think you addressed my questions.
> Andrew
>> Ok. Here's a patch that allows a remote target to pass watchpoint
>> information back to gdb using the T packet. It also fixes the T
>> packet handling to ignore other optional info which may not be
>> recognized. This changes the behavior to match the documentation.
>>
>> While testing this, I discovered that GDB tries to read data from
>> the watched address before the watchpoints are removed. This causes
>> another watchpoint exception so the stub returns an error response
>> to the read memory request.
>>
>> --Mark
>>
>>
>> Index: ChangeLog
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/ChangeLog,v
>> retrieving revision 1.744
>> diff -p -r1.744 ChangeLog
>> *** ChangeLog 2000/10/31 19:35:03 1.744
>> --- ChangeLog 2000/11/01 21:06:26
>> ***************
>> *** 1,3 ****
>> --- 1,10 ----
>> + 2000-11-01 Mark Salter <msalter@redhat.com>
>> +
>> + * remote.c (remote_wait): Add support to extract optional
>> + watchpoint information from T-packet. Ignore unrecognized
>> + optional info in T-packet.
>> + (remote_async_wait): Ditto.
>> +
>> 2000-10-30 Michael Snyder <msnyder@cleaver.cygnus.com>
>> * config/sh/tm-linux.h: New file. Include generic tm-linux.h,
>> Index: remote.c
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/remote.c,v
>> retrieving revision 1.26
>> diff -p -r1.26 remote.c
>> *** remote.c 2000/10/23 22:49:28 1.26
>> --- remote.c 2000/11/01 21:06:29
>> *************** void _initialize_remote (void);
>> *** 204,209 ****
>> --- 204,216 ----
>>
>> /* */
>>
>> + /* This is set to the data address of the access causing the target
>> + * to stop for a watchpoint. */
>> + static CORE_ADDR remote_watch_data_address;
>> +
>> + /* This is non-zero if taregt stopped for a watchpoint. */
>> + static int remote_stopped_by_watchpoint_p;
>> +
>> static struct target_ops remote_ops;
>>
>> static struct target_ops extended_remote_ops;
>> *************** struct gdb_ext_thread_info
>> *** 963,969 ****
>>
>> #define BUF_THREAD_ID_SIZE (OPAQUETHREADBYTES*2)
>>
>> ! char *unpack_varlen_hex (char *buff, int *result);
>>
>> static char *unpack_nibble (char *buf, int *val);
>>
>> --- 970,976 ----
>>
>> #define BUF_THREAD_ID_SIZE (OPAQUETHREADBYTES*2)
>>
>> ! char *unpack_varlen_hex (char *buff, ULONGEST *result);
>>
>> static char *unpack_nibble (char *buf, int *val);
>>
>> *************** stub_unpack_int (char *buff, int fieldle
>> *** 1084,1090 ****
>>
>> char *
>> unpack_varlen_hex (char *buff, /* packet to parse */
>> ! int *result)
>> {
>> int nibble;
>> int retval = 0;
>> --- 1091,1097 ----
>>
>> char *
>> unpack_varlen_hex (char *buff, /* packet to parse */
>> ! ULONGEST *result)
>> {
>> int nibble;
>> int retval = 0;
>> *************** remote_wait (int pid, struct target_wait
>> *** 2593,2598 ****
>> --- 2600,2606 ----
>> {
>> unsigned char *buf = alloca (PBUFSIZ);
>> int thread_num = -1;
>> + ULONGEST ul;
>>
status-> kind = TARGET_WAITKIND_EXITED;
status-> value.integer = 0;
>> *************** remote_wait (int pid, struct target_wait
>> *** 2610,2615 ****
>> --- 2618,2625 ----
>> if (target_wait_loop_hook)
>> (*target_wait_loop_hook) ();
>>
>> + remote_stopped_by_watchpoint_p = 0;
>> +
>> switch (buf[0])
>> {
>> case 'E': /* Error of some sort */
>> *************** Packet: '%s'\n",
>> *** 2647,2656 ****
>> p, buf);
>> if (strncmp ((const char *) p, "thread", p1 - p) == 0)
>> {
>> ! p_temp = unpack_varlen_hex (++p1, &thread_num);
>> record_currthread (thread_num);
>> p = (unsigned char *) p_temp;
>> }
>> }
>> else
>> {
>> --- 2657,2682 ----
>> p, buf);
>> if (strncmp ((const char *) p, "thread", p1 - p) == 0)
>> {
>> ! p_temp = unpack_varlen_hex (++p1, &ul);
>> ! thread_num = ul;
>> record_currthread (thread_num);
>> p = (unsigned char *) p_temp;
>> }
>> + else if ((strncmp ((const char *) p, "watch", p1 - p) == 0)
>> + || (strncmp ((const char *) p, "rwatch", p1 - p) == 0)
>> + || (strncmp ((const char *) p, "awatch", p1 - p) == 0))
>> + {
>> + remote_stopped_by_watchpoint_p = 1;
>> + p = unpack_varlen_hex (++p1, &ul);
>> + remote_watch_data_address = (CORE_ADDR)ul;
>> + }
>> + else
>> + {
>> + /* silently skip unknown optional info */
>> + p_temp = (unsigned char *) strchr ((const char *) p1+1, ';');
>> + if (p_temp)
>> + p = p_temp;
>> + }
>> }
>> else
>> {
>> *************** remote_async_wait (int pid, struct targe
>> *** 2808,2813 ****
>> --- 2834,2840 ----
>> {
>> unsigned char *buf = alloca (PBUFSIZ);
>> int thread_num = -1;
>> + ULONGEST ul;
>>
status-> kind = TARGET_WAITKIND_EXITED;
status-> value.integer = 0;
>> *************** remote_async_wait (int pid, struct targe
>> *** 2831,2836 ****
>> --- 2858,2865 ----
>> if (target_wait_loop_hook)
>> (*target_wait_loop_hook) ();
>>
>> + remote_stopped_by_watchpoint_p = 0;
>> +
>> switch (buf[0])
>> {
>> case 'E': /* Error of some sort */
>> *************** Packet: '%s'\n",
>> *** 2868,2877 ****
>> p, buf);
>> if (strncmp ((const char *) p, "thread", p1 - p) == 0)
>> {
>> ! p_temp = unpack_varlen_hex (++p1, &thread_num);
>> record_currthread (thread_num);
>> p = (unsigned char *) p_temp;
>> }
>> }
>> else
>> {
>> --- 2897,2922 ----
>> p, buf);
>> if (strncmp ((const char *) p, "thread", p1 - p) == 0)
>> {
>> ! p_temp = unpack_varlen_hex (++p1, &ul);
>> ! thread_num = ul;
>> record_currthread (thread_num);
>> p = (unsigned char *) p_temp;
>> }
>> + else if ((strncmp ((const char *) p, "watch", p1 - p) == 0)
>> + || (strncmp ((const char *) p, "rwatch", p1 - p) == 0)
>> + || (strncmp ((const char *) p, "awatch", p1 - p) == 0))
>> + {
>> + remote_stopped_by_watchpoint_p = 1;
>> + p = unpack_varlen_hex (++p1, &ul);
>> + remote_watch_data_address = (CORE_ADDR)ul;
>> + }
>> + else
>> + {
>> + /* silently skip unknown optional info */
>> + p_temp = (unsigned char *) strchr ((const char *) p1+1, ';');
>> + if (p_temp)
>> + p = p_temp;
>> + }
>> }
>> else
>> {
>> *************** remote_remove_hw_breakpoint (CORE_ADDR a
>> *** 4484,4489 ****
>> --- 4529,4551 ----
>> }
>> internal_error ("remote_remove_watchpoint: reached end of function");
>> }
>> +
>> + /* Returns data address if stopped by watchpoint.
>> + Zero otherwise. */
>> + CORE_ADDR
>> + remote_stopped_data_address (void)
>> + {
>> + if (remote_stopped_by_watchpoint_p)
>> + return remote_watch_data_address;
>> + return (CORE_ADDR)0;
>> + }
>> +
>> + int
>> + remote_stopped_by_watchpoint(void)
>> + {
>> + return remote_stopped_by_watchpoint_p;
>> + }
>> +
>>
>> /* Some targets are only capable of doing downloads, and afterwards
>> they switch to the remote serial protocol. This function provides
>> Index: doc/ChangeLog
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/doc/ChangeLog,v
>> retrieving revision 1.51
>> diff -p -r1.51 ChangeLog
>> *** ChangeLog 2000/10/16 07:34:02 1.51
>> --- ChangeLog 2000/11/01 21:06:31
>> ***************
>> *** 1,3 ****
>> --- 1,8 ----
>> + 2000-11-01 Mark Salter <msalter@redhat.com>
>> +
>> + * gdb.texinfo (Protocol): Document T packet extension to
>> + allow watchpoint address reporting.
>> +
>> 2000-10-16 Eli Zaretskii <eliz@is.elta.co.il>
>> * gdb.texinfo (Contributors, MIPS Embedded): Minor spelling
>> Index: doc/gdb.texinfo
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
>> retrieving revision 1.28
>> diff -p -r1.28 gdb.texinfo
>> *** gdb.texinfo 2000/10/16 07:34:02 1.28
>> --- gdb.texinfo 2000/11/01 21:06:40
>> *************** conventions is used.
>> *** 9390,9399 ****
>> @var{AA} = two hex digit signal number; @var{n...} = register number
>> (hex), @var{r...} = target byte ordered register contents, size defined
>> by @code{REGISTER_RAW_SIZE}; @var{n...} = @samp{thread}, @var{r...} =
>> ! thread process ID, this is a hex integer; @var{n...} = other string not
>> ! starting with valid hex digit. @value{GDBN} should ignore this
>> ! @var{n...}, @var{r...} pair and go on to the next. This way we can
>> ! extend the protocol.
>>
>> @item @code{W}@var{AA}
>> @tab
>> --- 9390,9400 ----
>> @var{AA} = two hex digit signal number; @var{n...} = register number
>> (hex), @var{r...} = target byte ordered register contents, size defined
>> by @code{REGISTER_RAW_SIZE}; @var{n...} = @samp{thread}, @var{r...} =
>> ! thread process ID, this is a hex integer; @var{n...} = (@samp{watch} |
>> ! @samp{rwatch} | @samp{awatch}, @var{r...} = data address, this is a hex
>> ! integer; @var{n...} = other string not starting with valid hex digit.
>> ! @value{GDBN} should ignore this @var{n...}, @var{r...} pair and go on
>> ! to the next. This way we can extend the protocol.
>>
>> @item @code{W}@var{AA}
>> @tab
>>
>>
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