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Re: [gdbserver/patch] Z packet support
- From: Orjan Friberg <orjan dot friberg at axis dot com>
- To: Daniel Jacobowitz <drow at false dot org>
- Cc: gdb-patches at sources dot redhat dot com
- Date: Wed, 12 Jan 2005 14:34:33 +0100
- Subject: Re: [gdbserver/patch] Z packet support
- Organization: Axis Communications
- References: <41ADDF6B.2040601@axis.com> <20041207023346.GA2524@nevyn.them.org>
Daniel Jacobowitz wrote:
I'm fine with the approach. The implementation needs a bit of work,
though.
There's a new ChangeLog entry (date change only) and patch at the end. A couple
of comments to what you wrote first through:
+ addr = (*the_target->stopped_data_address) ();
+
+ *buf++ = tohex ((addr >> 28) & 0xf);
+ *buf++ = tohex ((addr >> 24) & 0xf);
+ *buf++ = tohex ((addr >> 20) & 0xf);
+ *buf++ = tohex ((addr >> 16) & 0xf);
+
+ *buf++ = tohex ((addr >> 12) & 0xf);
+ *buf++ = tohex ((addr >> 8) & 0xf);
+ *buf++ = tohex ((addr >> 4) & 0xf);
+ *buf++ = tohex (addr & 0xf);
+
+ *buf++ = ';';
+ }
This is broken on 64-bit targets. This will require a certain amount
of shuffling to figure out the proper size of an address.
Living comfortably in a 32-bit world, I may have missed what you mean by "a
certain amount of shuffling". I imagined a simple sizeof (addr) would do.
- Some of the z/Z commands are breakpoints, not watchpoints. Please
only invoke watchpoint methods for watchpoint commands.
I assume you mean that I should exclude memory breakpoint and hardware
breakpoint. Anyway, that's what I did.
2005-01-12 Orjan Friberg <orjanf@axis.com>
* target.h (struct target_ops): Add insert_watchpoint,
remove_watchpoint, stopped_by_watchpoint, stopped_data_address function
pointers for hardware watchpoint support.
* linux-low.h (struct linux_target_ops): Ditto.
* linux-low.c (linux_insert_watchpoint, linux_remove_watchpoint)
(linux_stopped_by_watchpoint, linux_stopped_data_address): New. Add
to linux_target_ops.
* remote-utils.c (prepare_resume_reply): Add watchpoint information to
reply packet.
* server.c (main): Recognize 'Z' and 'z' packets.
Index: target.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/target.h,v
retrieving revision 1.11
diff -u -p -r1.11 target.h
--- target.h 5 Mar 2004 03:43:19 -0000 1.11
+++ target.h 12 Jan 2005 13:23:55 -0000
@@ -133,6 +133,27 @@ struct target_ops
Read LEN bytes at OFFSET into a buffer at MYADDR. */
int (*read_auxv) (CORE_ADDR offset, char *myaddr, unsigned int len);
+
+ /* Insert and remove a hardware watchpoint.
+ Returns 0 on success, -1 on failure and 1 on unsupported.
+ The type is coded as follows:
+ 2 = write watchpoint
+ 3 = read watchpoint
+ 4 = access watchpoint
+ */
+
+ int (*insert_watchpoint) (char type, CORE_ADDR addr, int len);
+ int (*remove_watchpoint) (char type, CORE_ADDR addr, int len);
+
+ /* Returns 1 if target was stopped due to a watchpoint hit, 0 otherwise. */
+
+ int (*stopped_by_watchpoint) (void);
+
+ /* Returns the address associated with the watchpoint that hit, if any;
+ returns 0 otherwise. */
+
+ CORE_ADDR (*stopped_data_address) (void);
+
};
extern struct target_ops *the_target;
Index: linux-low.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/linux-low.h,v
retrieving revision 1.7
diff -u -p -r1.7 linux-low.h
--- linux-low.h 31 Jan 2004 22:19:32 -0000 1.7
+++ linux-low.h 12 Jan 2005 13:23:55 -0000
@@ -57,6 +57,13 @@ struct linux_target_ops
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);
+
};
extern struct linux_target_ops the_low_target;
Index: linux-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/linux-low.c,v
retrieving revision 1.33
diff -u -p -r1.33 linux-low.c
--- linux-low.c 16 Oct 2004 17:42:00 -0000 1.33
+++ linux-low.c 12 Jan 2005 13:23:55 -0000
@@ -1466,7 +1466,47 @@ linux_read_auxv (CORE_ADDR offset, char
return n;
}
-
+/* These watchpoint related wrapper functions simply pass on the function call
+ if the target has registered a corresponding function. */
+
+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);
+ else
+ /* Unsupported (see target.h). */
+ return 1;
+}
+
+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);
+ else
+ /* Unsupported (see target.h). */
+ return 1;
+}
+
+static int
+linux_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
+linux_stopped_data_address (void)
+{
+ if (the_low_target.stopped_data_address != NULL)
+ return the_low_target.stopped_data_address ();
+ else
+ return 0;
+}
+
static struct target_ops linux_target_ops = {
linux_create_inferior,
linux_attach,
@@ -1482,6 +1522,10 @@ static struct target_ops linux_target_op
linux_look_up_symbols,
linux_send_signal,
linux_read_auxv,
+ linux_insert_watchpoint,
+ linux_remove_watchpoint,
+ linux_stopped_by_watchpoint,
+ linux_stopped_data_address,
};
static void
Index: remote-utils.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/remote-utils.c,v
retrieving revision 1.22
diff -u -p -r1.22 remote-utils.c
--- remote-utils.c 16 Oct 2004 17:42:00 -0000 1.22
+++ remote-utils.c 12 Jan 2005 13:23:56 -0000
@@ -639,6 +639,26 @@ prepare_resume_reply (char *buf, char st
if (status == 'T')
{
const char **regp = gdbserver_expedite_regs;
+
+ if (the_target->stopped_by_watchpoint != NULL
+ && (*the_target->stopped_by_watchpoint) ())
+ {
+ CORE_ADDR addr;
+ int i;
+
+ strncpy (buf, "watch:", 6);
+ buf += 6;
+
+ addr = (*the_target->stopped_data_address) ();
+
+ /* Convert each byte of the address into two hexadecimal chars. */
+ for (i = sizeof (addr) * 2; i > 0; i--)
+ {
+ *buf++ = tohex ((addr >> (i - 1) * 4) & 0xf);
+ }
+ *buf++ = ';';
+ }
+
while (*regp)
{
buf = outreg (find_regno (*regp), buf);
Index: server.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/server.c,v
retrieving revision 1.22
diff -u -p -r1.22 server.c
--- server.c 5 Mar 2004 03:44:27 -0000 1.22
+++ server.c 12 Jan 2005 13:23:56 -0000
@@ -508,6 +508,66 @@ main (int argc, char *argv[])
signal = mywait (&status, 1);
prepare_resume_reply (own_buf, status, signal);
break;
+ case 'Z':
+ {
+ char *lenptr;
+ char *dataptr;
+ CORE_ADDR addr = strtoul (&own_buf[3], &lenptr, 16);
+ int len = strtol (lenptr + 1, &dataptr, 16);
+ char type = own_buf[1];
+
+ if (the_target->insert_watchpoint == NULL
+ || (type < '2' || type > '4'))
+ {
+ /* No watchpoint support or not a watchpoint command;
+ unrecognized either way. */
+ own_buf[0] = '\0';
+ }
+ else
+ {
+ int res;
+
+ res = (*the_target->insert_watchpoint) (type, addr, len);
+ if (res == 0)
+ write_ok (own_buf);
+ else if (res == 1)
+ /* Unsupported. */
+ own_buf[0] = '\0';
+ else
+ write_enn (own_buf);
+ }
+ break;
+ }
+ case 'z':
+ {
+ char *lenptr;
+ char *dataptr;
+ CORE_ADDR addr = strtoul (&own_buf[3], &lenptr, 16);
+ int len = strtol (lenptr + 1, &dataptr, 16);
+ char type = own_buf[1];
+
+ if (the_target->remove_watchpoint == NULL
+ || (type < '2' || type > '4'))
+ {
+ /* No watchpoint support or not a watchpoint command;
+ unrecognized either way. */
+ own_buf[0] = '\0';
+ }
+ else
+ {
+ int res;
+
+ res = (*the_target->remove_watchpoint) (type, addr, len);
+ if (res == 0)
+ write_ok (own_buf);
+ else if (res == 1)
+ /* Unsupported. */
+ own_buf[0] = '\0';
+ else
+ write_enn (own_buf);
+ }
+ break;
+ }
case 'k':
fprintf (stderr, "Killing inferior\n");
kill_inferior ();
--
Orjan Friberg
Axis Communications