[GIT PULL] kgdb/kdb updates for 3.1

[GIT PULL] kgdb/kdb updates for 3.1

[Jason Wessel]

Linus, please pull the for_linus branch to pick up the minor kgdb/kdb
cleanups accumulated in the last few months.

git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb.git for_linus

Thanks,
Jason.

---

The following changes since commit 02f8c6aee8df3cdc935e9bdd4f2d020306035dbe:

  Linux 3.0 (2011-07-21 19:17:23 -0700)

are available in the git repository at:
  git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb.git for_linus

Jason Wessel (4):
      kdb: cleanup unused variables missed in the original kdb merge
      kdb,kgdb: Implement switch and pass buffer from kdb -> gdb
      kdb: Remove all references to DOING_KGDB2
      kdb,kgdb: Allow arbitrary kgdb magic knock sequences

 kernel/debug/gdbstub.c          |   22 +++++++++++++++-------
 kernel/debug/kdb/kdb_bt.c       |    5 ++---
 kernel/debug/kdb/kdb_cmds       |    4 ----
 kernel/debug/kdb/kdb_debugger.c |   21 ++++++++-------------
 kernel/debug/kdb/kdb_io.c       |   36 +++++++++++++++++++++++++-----------
 kernel/debug/kdb/kdb_main.c     |    4 ++--
 kernel/debug/kdb/kdb_private.h  |    3 +--
 7 files changed, 53 insertions(+), 42 deletions(-)

[PATCH 1/4] kdb: cleanup unused variables missed in the original kdb merge

[Jason Wessel]

The BTARGS and BTSYMARG variables do not have any function in the
mainline version of kdb.

Reported-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
---
 kernel/debug/kdb/kdb_bt.c   |    5 ++---
 kernel/debug/kdb/kdb_cmds   |    4 ----
 kernel/debug/kdb/kdb_main.c |    2 +-
 3 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 2f62fe8..7179eac 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -112,9 +112,8 @@ kdb_bt(int argc, const char **argv)
 	unsigned long addr;
 	long offset;
 
-	kdbgetintenv("BTARGS", &argcount);	/* Arguments to print */
-	kdbgetintenv("BTAPROMPT", &btaprompt);	/* Prompt after each
-						 * proc in bta */
+	/* Prompt after each proc in bta */
+	kdbgetintenv("BTAPROMPT", &btaprompt);
 
 	if (strcmp(argv[0], "bta") == 0) {
 		struct task_struct *g, *p;
diff --git a/kernel/debug/kdb/kdb_cmds b/kernel/debug/kdb/kdb_cmds
index 56c88e4..9834ad3 100644
--- a/kernel/debug/kdb/kdb_cmds
+++ b/kernel/debug/kdb/kdb_cmds
@@ -18,16 +18,12 @@ defcmd dumpcommon "" "Common kdb debugging"
 endefcmd
 
 defcmd dumpall "" "First line debugging"
-  set BTSYMARG 1
-  set BTARGS 9
   pid R
   -dumpcommon
   -bta
 endefcmd
 
 defcmd dumpcpu "" "Same as dumpall but only tasks on cpus"
-  set BTSYMARG 1
-  set BTARGS 9
   pid R
   -dumpcommon
   -btc
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index be14779..b33116e 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -145,7 +145,6 @@ static char *__env[] = {
 #endif
  "RADIX=16",
  "MDCOUNT=8",			/* lines of md output */
- "BTARGS=9",			/* 9 possible args in bt */
  KDB_PLATFORM_ENV,
  "DTABCOUNT=30",
  "NOSECT=1",
@@ -172,6 +171,7 @@ static char *__env[] = {
  (char *)0,
  (char *)0,
  (char *)0,
+ (char *)0,
 };
 
 static const int __nenv = (sizeof(__env) / sizeof(char *));
-- 
1.7.1

[PATCH 2/4] kdb,kgdb: Implement switch and pass buffer from kdb -> gdb

[Jason Wessel]

When switching from kdb mode to kgdb mode packets were getting lost
depending on the size of the fifo queue of the serial chip.  When gdb
initially connects if it is in kdb mode it should entirely send any
character buffer over to the gdbstub when switching connections.

Previously kdb was zero'ing out the character buffer and this could
lead to gdb failing to connect at all, or a lengthy pause could occur
on the initial connect.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
---
 kernel/debug/gdbstub.c          |   22 +++++++++++++++-------
 kernel/debug/kdb/kdb_debugger.c |   17 +++++++----------
 kernel/debug/kdb/kdb_io.c       |   10 ++++++----
 kernel/debug/kdb/kdb_private.h  |    1 +
 4 files changed, 29 insertions(+), 21 deletions(-)

diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c
index a11db95..3487248 100644
--- a/kernel/debug/gdbstub.c
+++ b/kernel/debug/gdbstub.c
@@ -42,6 +42,8 @@
 /* Our I/O buffers. */
 static char			remcom_in_buffer[BUFMAX];
 static char			remcom_out_buffer[BUFMAX];
+static int			gdbstub_use_prev_in_buf;
+static int			gdbstub_prev_in_buf_pos;
 
 /* Storage for the registers, in GDB format. */
 static unsigned long		gdb_regs[(NUMREGBYTES +
@@ -58,6 +60,13 @@ static int gdbstub_read_wait(void)
 	int ret = -1;
 	int i;
 
+	if (unlikely(gdbstub_use_prev_in_buf)) {
+		if (gdbstub_prev_in_buf_pos < gdbstub_use_prev_in_buf)
+			return remcom_in_buffer[gdbstub_prev_in_buf_pos++];
+		else
+			gdbstub_use_prev_in_buf = 0;
+	}
+
 	/* poll any additional I/O interfaces that are defined */
 	while (ret < 0)
 		for (i = 0; kdb_poll_funcs[i] != NULL; i++) {
@@ -109,7 +118,6 @@ static void get_packet(char *buffer)
 			buffer[count] = ch;
 			count = count + 1;
 		}
-		buffer[count] = 0;
 
 		if (ch == '#') {
 			xmitcsum = hex_to_bin(gdbstub_read_wait()) << 4;
@@ -124,6 +132,7 @@ static void get_packet(char *buffer)
 			if (dbg_io_ops->flush)
 				dbg_io_ops->flush();
 		}
+		buffer[count] = 0;
 	} while (checksum != xmitcsum);
 }
 
@@ -1082,12 +1091,11 @@ int gdbstub_state(struct kgdb_state *ks, char *cmd)
 	case 'c':
 		strcpy(remcom_in_buffer, cmd);
 		return 0;
-	case '?':
-		gdb_cmd_status(ks);
-		break;
-	case '\0':
-		strcpy(remcom_out_buffer, "");
-		break;
+	case '$':
+		strcpy(remcom_in_buffer, cmd);
+		gdbstub_use_prev_in_buf = strlen(remcom_in_buffer);
+		gdbstub_prev_in_buf_pos = 0;
+		return 0;
 	}
 	dbg_io_ops->write_char('+');
 	put_packet(remcom_out_buffer);
diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c
index dd0b1b7..fe422d2 100644
--- a/kernel/debug/kdb/kdb_debugger.c
+++ b/kernel/debug/kdb/kdb_debugger.c
@@ -30,6 +30,8 @@ EXPORT_SYMBOL_GPL(kdb_poll_funcs);
 int kdb_poll_idx = 1;
 EXPORT_SYMBOL_GPL(kdb_poll_idx);
 
+static struct kgdb_state *kdb_ks;
+
 int kdb_stub(struct kgdb_state *ks)
 {
 	int error = 0;
@@ -39,6 +41,7 @@ int kdb_stub(struct kgdb_state *ks)
 	kdb_dbtrap_t db_result = KDB_DB_NOBPT;
 	int i;
 
+	kdb_ks = ks;
 	if (KDB_STATE(REENTRY)) {
 		reason = KDB_REASON_SWITCH;
 		KDB_STATE_CLEAR(REENTRY);
@@ -124,16 +127,6 @@ int kdb_stub(struct kgdb_state *ks)
 	kdbnearsym_cleanup();
 	if (error == KDB_CMD_KGDB) {
 		if (KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)) {
-	/*
-	 * This inteface glue which allows kdb to transition in into
-	 * the gdb stub.  In order to do this the '?' or '' gdb serial
-	 * packet response is processed here.  And then control is
-	 * passed to the gdbstub.
-	 */
-			if (KDB_STATE(DOING_KGDB))
-				gdbstub_state(ks, "?");
-			else
-				gdbstub_state(ks, "");
 			KDB_STATE_CLEAR(DOING_KGDB);
 			KDB_STATE_CLEAR(DOING_KGDB2);
 		}
@@ -166,3 +159,7 @@ int kdb_stub(struct kgdb_state *ks)
 	return kgdb_info[ks->cpu].ret_state;
 }
 
+void kdb_gdb_state_pass(char *buf)
+{
+	gdbstub_state(kdb_ks, buf);
+}
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 96fdaac..bd23326 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -35,8 +35,8 @@ static void kgdb_transition_check(char *buffer)
 {
 	int slen = strlen(buffer);
 	if (strncmp(buffer, "$?#3f", slen) != 0 &&
-	    strncmp(buffer, "$qSupported#37", slen) != 0 &&
-	    strncmp(buffer, "+$qSupported#37", slen) != 0) {
+	    strncmp(buffer, "$qSupported", slen) != 0 &&
+	    strncmp(buffer, "+$qSupported", slen) != 0) {
 		KDB_STATE_SET(KGDB_TRANS);
 		kdb_printf("%s", buffer);
 	}
@@ -390,12 +390,14 @@ poll_again:
 			/* Special escape to kgdb */
 			if (lastchar - buffer >= 5 &&
 			    strcmp(lastchar - 5, "$?#3f") == 0) {
+				kdb_gdb_state_pass(lastchar - 5);
 				strcpy(buffer, "kgdb");
 				KDB_STATE_SET(DOING_KGDB);
 				return buffer;
 			}
-			if (lastchar - buffer >= 14 &&
-			    strcmp(lastchar - 14, "$qSupported#37") == 0) {
+			if (lastchar - buffer >= 11 &&
+			    strcmp(lastchar - 11, "$qSupported") == 0) {
+				kdb_gdb_state_pass(lastchar - 11);
 				strcpy(buffer, "kgdb");
 				KDB_STATE_SET(DOING_KGDB2);
 				return buffer;
diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
index 35d69ed..03d332e 100644
--- a/kernel/debug/kdb/kdb_private.h
+++ b/kernel/debug/kdb/kdb_private.h
@@ -218,6 +218,7 @@ extern void kdb_print_nameval(const char *name, unsigned long val);
 extern void kdb_send_sig_info(struct task_struct *p, struct siginfo *info);
 extern void kdb_meminfo_proc_show(void);
 extern char *kdb_getstr(char *, size_t, char *);
+extern void kdb_gdb_state_pass(char *buf);
 
 /* Defines for kdb_symbol_print */
 #define KDB_SP_SPACEB	0x0001		/* Space before string */
-- 
1.7.1

[PATCH 3/4] kdb: Remove all references to DOING_KGDB2

[Jason Wessel]

The DOING_KGDB2 was originally a state variable for one of the two
ways to automatically transition from kdb to kgdb.  Purge all these
variables and just use one single state for the transition.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
---
 kernel/debug/kdb/kdb_debugger.c |    4 +---
 kernel/debug/kdb/kdb_io.c       |    2 +-
 kernel/debug/kdb/kdb_main.c     |    2 +-
 kernel/debug/kdb/kdb_private.h  |    2 --
 4 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c
index fe422d2..d9ca9aa 100644
--- a/kernel/debug/kdb/kdb_debugger.c
+++ b/kernel/debug/kdb/kdb_debugger.c
@@ -126,10 +126,8 @@ int kdb_stub(struct kgdb_state *ks)
 	KDB_STATE_CLEAR(PAGER);
 	kdbnearsym_cleanup();
 	if (error == KDB_CMD_KGDB) {
-		if (KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)) {
+		if (KDB_STATE(DOING_KGDB))
 			KDB_STATE_CLEAR(DOING_KGDB);
-			KDB_STATE_CLEAR(DOING_KGDB2);
-		}
 		return DBG_PASS_EVENT;
 	}
 	kdb_bp_install(ks->linux_regs);
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index bd23326..0dbcdfb 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -399,7 +399,7 @@ poll_again:
 			    strcmp(lastchar - 11, "$qSupported") == 0) {
 				kdb_gdb_state_pass(lastchar - 11);
 				strcpy(buffer, "kgdb");
-				KDB_STATE_SET(DOING_KGDB2);
+				KDB_STATE_SET(DOING_KGDB);
 				return buffer;
 			}
 		}
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index b33116e..63786e7 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -1386,7 +1386,7 @@ int kdb_main_loop(kdb_reason_t reason, kdb_reason_t reason2, int error,
 		}
 
 		if (result == KDB_CMD_KGDB) {
-			if (!(KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)))
+			if (!KDB_STATE(DOING_KGDB))
 				kdb_printf("Entering please attach debugger "
 					   "or use $D#44+ or $3#33\n");
 			break;
diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
index 03d332e..e381d10 100644
--- a/kernel/debug/kdb/kdb_private.h
+++ b/kernel/debug/kdb/kdb_private.h
@@ -21,7 +21,6 @@
 #define KDB_CMD_SS	(-1003)
 #define KDB_CMD_SSB	(-1004)
 #define KDB_CMD_KGDB (-1005)
-#define KDB_CMD_KGDB2 (-1006)
 
 /* Internal debug flags */
 #define KDB_DEBUG_FLAG_BP	0x0002	/* Breakpoint subsystem debug */
@@ -146,7 +145,6 @@ extern int kdb_state;
 						 * keyboard on this cpu */
 #define KDB_STATE_KEXEC		0x00040000	/* kexec issued */
 #define KDB_STATE_DOING_KGDB	0x00080000	/* kgdb enter now issued */
-#define KDB_STATE_DOING_KGDB2	0x00100000	/* kgdb enter now issued */
 #define KDB_STATE_KGDB_TRANS	0x00200000	/* Transition to kgdb */
 #define KDB_STATE_ARCH		0xff000000	/* Reserved for arch
 						 * specific use */
-- 
1.7.1

[PATCH 4/4] kdb,kgdb: Allow arbitrary kgdb magic knock sequences

[Jason Wessel]

The first packet that gdb sends when the kernel is in kdb mode seems
to change with every release of gdb.  Instead of continuing to add
many different gdb packets, change kdb to automatically look for any
thing that looks like a gdb packet.

Example 1 cold start test:
echo g > /proc/sysrq-trigger
$D#44+

Example 2 cold start test:
echo g > /proc/sysrq-trigger
$3#33

The second one should re-enter kdb's shell right away and is purely a
test.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
---
 kernel/debug/kdb/kdb_io.c |   28 ++++++++++++++++++++--------
 1 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 0dbcdfb..4802eb5 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -31,15 +31,21 @@ char kdb_prompt_str[CMD_BUFLEN];
 
 int kdb_trap_printk;
 
-static void kgdb_transition_check(char *buffer)
+static int kgdb_transition_check(char *buffer)
 {
-	int slen = strlen(buffer);
-	if (strncmp(buffer, "$?#3f", slen) != 0 &&
-	    strncmp(buffer, "$qSupported", slen) != 0 &&
-	    strncmp(buffer, "+$qSupported", slen) != 0) {
+	if (buffer[0] != '+' && buffer[0] != '$') {
 		KDB_STATE_SET(KGDB_TRANS);
 		kdb_printf("%s", buffer);
+	} else {
+		int slen = strlen(buffer);
+		if (slen > 3 && buffer[slen - 3] == '#') {
+			kdb_gdb_state_pass(buffer);
+			strcpy(buffer, "kgdb");
+			KDB_STATE_SET(DOING_KGDB);
+			return 1;
+		}
 	}
+	return 0;
 }
 
 static int kdb_read_get_key(char *buffer, size_t bufsize)
@@ -251,6 +257,10 @@ poll_again:
 	case 13: /* enter */
 		*lastchar++ = '\n';
 		*lastchar++ = '\0';
+		if (!KDB_STATE(KGDB_TRANS)) {
+			KDB_STATE_SET(KGDB_TRANS);
+			kdb_printf("%s", buffer);
+		}
 		kdb_printf("\n");
 		return buffer;
 	case 4: /* Del */
@@ -382,10 +392,12 @@ poll_again:
 				 * printed characters if we think that
 				 * kgdb is connecting, until the check
 				 * fails */
-				if (!KDB_STATE(KGDB_TRANS))
-					kgdb_transition_check(buffer);
-				else
+				if (!KDB_STATE(KGDB_TRANS)) {
+					if (kgdb_transition_check(buffer))
+						return buffer;
+				} else {
 					kdb_printf("%c", key);
+				}
 			}
 			/* Special escape to kgdb */
 			if (lastchar - buffer >= 5 &&
-- 
1.7.1