[PATCH][3/3] Update CVS KGDB's wrt connect / detach

From: Tom Rini
Date: Wed Feb 25 2004 - 16:59:01 EST

The following patch fixes a number of little issues here and there, and
ends up making things more robust.
- We don't need kgdb_might_be_resumed or kgdb_killed_or_detached.
GDB attaching is GDB attaching, we haven't preserved any of the
previous context anyhow.
- Don't try and look for a connection in put_packet, after we've tried
to put a packet. Instead, when we receive a packet, GDB has
connected.
- Remove ok_packet(), excessive, IMHO.

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
# ChangeSet 1.1664 -> 1.1665
# arch/ppc/8260_io/uart.c 1.31 -> 1.32
# kernel/kgdb.c 1.4 -> 1.5
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 04/02/25 trini@xxxxxxxxxxxxxxxxxxx 1.1665
# - Kill kgdb_might_be_resumed and kgdb_killed_or_detached.
# - Spacing and comments.
# - put_packet doesn't try and check for a connect now.
# - Kill ok_packet().
# - Only send an initial packet in kgdb_handle_exception if
# kgdb has connected already.
# --------------------------------------------
#
diff -Nru a/arch/ppc/8260_io/uart.c b/arch/ppc/8260_io/uart.c
--- a/arch/ppc/8260_io/uart.c Wed Feb 25 14:21:38 2004
+++ b/arch/ppc/8260_io/uart.c Wed Feb 25 14:21:38 2004
@@ -396,14 +396,8 @@
#ifdef CONFIG_KGDB
if (info->state->smc_scc_num == KGDB_SER_IDX) {
while (i-- > 0) {
- if (*cp == 0x03) {
+ if (*cp == 0x03 || *cp == '$') {
breakpoint();
- return;
- }
- if (*cp == '$') {
- atomic_set(&kgdb_might_be_resumed, 1);
- breakpoint();
- atomic_set(&kgdb_might_be_resumed, 0);
return;
}
cp++;
diff -Nru a/kernel/kgdb.c b/kernel/kgdb.c
--- a/kernel/kgdb.c Wed Feb 25 14:21:38 2004
+++ b/kernel/kgdb.c Wed Feb 25 14:21:38 2004
@@ -15,6 +15,7 @@
* Copyright (C) 2002-2004 Timesys Corporation
* Copyright (C) 2003-2004 Amit S. Kale
* Copyright (C) 2004 Pavel Machek <pavel@xxxxxxx>
+ * Copyright (C) 2004 Tom Rini <trini@xxxxxxxxxxxxxxxxxxx>
*
* Restructured KGDB for 2.6 kernels.
* thread support, support for multiple processors,support for ia-32(x86)
@@ -87,8 +88,6 @@
static spinlock_t slavecpulocks[KGDB_MAX_NO_CPUS];
static volatile int procindebug[KGDB_MAX_NO_CPUS];
atomic_t kgdb_setting_breakpoint;
-atomic_t kgdb_killed_or_detached;
-atomic_t kgdb_might_be_resumed;
struct task_struct *kgdb_usethread, *kgdb_contthread;

int debugger_step;
@@ -212,8 +211,10 @@
char ch;

do {
- /* wait around for the start character, ignore all other characters */
- while ((ch = (kgdb_serial->read_char() & 0x7f)) != '$') ;
+ /* wait around for the start character, ignore all other
+ * characters */
+ while ((ch = (kgdb_serial->read_char() & 0x7f)) != '$')
+ ; /* Spin. */
kgdb_connected = 1;
checksum = 0;
xmitcsum = -1;
@@ -249,27 +250,22 @@
* Send the packet in buffer.
* Check for gdb connection if asked for.
*/
-static void put_packet(char *buffer, int checkconnect)
+static void put_packet(char *buffer)
{
unsigned char checksum;
int count;
char ch;
- static char gdbseq[] = "$Hc-1#09";
- int i;
- int send_count;

/* $<packet info>#<checksum>. */
do {
kgdb_serial->write_char('$');
checksum = 0;
count = 0;
- send_count = 0;

while ((ch = buffer[count])) {
kgdb_serial->write_char(ch);
checksum += ch;
count++;
- send_count++;
}

kgdb_serial->write_char('#');
@@ -277,30 +273,7 @@
kgdb_serial->write_char(hexchars[checksum % 16]);
if (kgdb_serial->flush)
kgdb_serial->flush();
-
- i = 0;
- while ((ch = kgdb_serial->read_char()) == gdbseq[i++] &&
- checkconnect) {
- if (!gdbseq[i]) {
- kgdb_serial->write_char('+');
- if (kgdb_serial->flush)
- kgdb_serial->flush();
- breakpoint();
-
- /*
- * GDB is available now.
- * Retransmit this packet.
- */
- break;
- }
- }
- if (checkconnect && ch == 3) {
- kgdb_serial->write_char('+');
- if (kgdb_serial->flush)
- kgdb_serial->flush();
- breakpoint();
- }
- } while ((ch & 0x7f) != '+');
+ } while ((kgdb_serial->read_char() & 0x7f) != '+');

}

@@ -427,11 +400,6 @@
pkt[3] = '\0';
}

-static void ok_packet(char *pkt)
-{
- strcpy(pkt, "OK");
-}
-
static char *pack_threadid(char *pkt, threadref * id)
{
char *limit;
@@ -502,7 +470,8 @@
procindebug[processor] = 1;
current->thread.debuggerinfo = regs;

- /* Wait till master processor goes completely into the debugger. FIXME: this looks racy */
+ /* Wait till master processor goes completely into the debugger.
+ * FIXME: this looks racy */
while (!procindebug[atomic_read(&debugger_active) - 1]) {
int i = 10; /* an arbitrary number */

@@ -701,17 +670,7 @@
/* Master processor is completely in the debugger */
kgdb_post_master_code(linux_regs, exVector, err_code);

- if (atomic_read(&kgdb_killed_or_detached) &&
- atomic_read(&kgdb_might_be_resumed)) {
- get_packet(remcom_in_buffer);
- if (remcom_in_buffer[0] == 'H' && remcom_in_buffer[1] == 'c') {
- remove_all_break();
- atomic_set(&kgdb_killed_or_detached, 0);
- ok_packet(remcom_out_buffer);
- } else
- return 1;
- } else {
-
+ if (kgdb_connected) {
/* reply to host that an exception has occurred */
ptr = remcom_out_buffer;
*ptr++ = 'T';
@@ -721,11 +680,9 @@
int_to_threadref(&thref, shadow_pid(current->pid));
ptr = pack_threadid(ptr, &thref);
*ptr++ = ';';
- *ptr = '\0';
- }

- put_packet(remcom_out_buffer, 0);
- kgdb_connected = 1;
+ put_packet(remcom_out_buffer);
+ }

kgdb_usethread = current;
kgdb_usethreadid = shadow_pid(current->pid);
@@ -798,7 +755,7 @@
else {
gdb_regs_to_regs(gdb_regs, (struct pt_regs *)
current->thread.debuggerinfo);
- ok_packet(remcom_out_buffer);
+ strcpy(remcom_out_buffer, "OK");
}

break;
@@ -838,10 +795,10 @@
if ((error = remove_all_break()) < 0) {
error_packet(remcom_out_buffer, error);
} else {
- ok_packet(remcom_out_buffer);
+ strcpy(remcom_out_buffer, "OK");
kgdb_connected = 0;
}
- put_packet(remcom_out_buffer, 0);
+ put_packet(remcom_out_buffer);
goto default_handle;

case 'k':
@@ -947,11 +904,10 @@
}
kgdb_usethread = thread;
kgdb_usethreadid = threadid;
- ok_packet(remcom_out_buffer);
+ strcpy(remcom_out_buffer, "OK");
break;

case 'c':
- atomic_set(&kgdb_killed_or_detached, 0);
ptr = &remcom_in_buffer[2];
kgdb_hex2long(&ptr, &threadid);
if (!threadid) {
@@ -966,7 +922,7 @@
}
kgdb_contthread = thread;
}
- ok_packet(remcom_out_buffer);
+ strcpy(remcom_out_buffer, "OK");
break;
}
break;
@@ -977,7 +933,7 @@
kgdb_hex2long(&ptr, &threadid);
thread = getthread(linux_regs, threadid);
if (thread)
- ok_packet(remcom_out_buffer);
+ strcpy(remcom_out_buffer, "OK");
else
error_packet(remcom_out_buffer, -EINVAL);
break;
@@ -1018,7 +974,7 @@
}

if (error == 0)
- ok_packet(remcom_out_buffer);
+ strcpy(remcom_out_buffer, "OK");
else
error_packet(remcom_out_buffer, error);

@@ -1039,7 +995,7 @@
} /* switch */

/* reply to the request */
- put_packet(remcom_out_buffer, 0);
+ put_packet(remcom_out_buffer);
}

kgdb_exit:
@@ -1063,7 +1019,6 @@
}

/* Free debugger_active */
- atomic_set(&kgdb_killed_or_detached, 1);
atomic_set(&debugger_active, 0);
local_irq_restore(flags);

@@ -1132,12 +1087,6 @@
/* Free debugger_active */
atomic_set(&debugger_active, 0);

- /* This flag is used, if gdb has detached and wants to start
- * another session
- */
- atomic_set(&kgdb_killed_or_detached, 1);
- atomic_set(&kgdb_might_be_resumed, 0);
-
for (i = 0; i < MAX_BREAKPOINTS; i++)
kgdb_break[i].state = bp_disabled;

@@ -1222,7 +1171,7 @@
*bufptr = '\0';
s += wcount;

- put_packet(kgdbconbuf, 1);
+ put_packet(kgdbconbuf);

}
local_irq_restore(flags);
--
Tom Rini
http://gate.crashing.org/~trini/
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