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

[Tom Rini <trini@kernel.crashing.org>]

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@kernel.crashing.org	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@suse.cz>
+ * Copyright (C) 2004 Tom Rini <trini@kernel.crashing.org>
  *
  * 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/