kdb,kgdb: Implement switch and pass buffer from kdb -> gdb

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.

Jason Wessel committed 15 years ago

Commit f679c491 parent 3bdb65e4 files · +29 −21Browse files

Showing the changes to kernel/debug (4 of 4 files). Show all

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4 files

kernel/debug/gdbstub.c +15 −7
kernel/debug/kdb/kdb_debugger.c +7 −10
kernel/debug/kdb/kdb_io.c +6 −4
kernel/debug/kdb/kdb_private.h +1 −0

kernel/debug/gdbstub.c+15−7

@@ -42,6 +42,8 @@ · 41 unmodified lines
42	42	/* Our I/O buffers. */
43	43	static char remcom_in_buffer[BUFMAX];
44	44	static char remcom_out_buffer[BUFMAX];
	45	+static int gdbstub_use_prev_in_buf;
	46	+static int gdbstub_prev_in_buf_pos;
45	47
46	48	/* Storage for the registers, in GDB format. */
47	49	static unsigned long gdb_regs[(NUMREGBYTES +
@@ -58,6 +60,13 @@ static int gdbstub_read_wait(void) · 10 unmodified lines
58	60	int ret = -1;
59	61	int i;
60	62
	63	+ if (unlikely(gdbstub_use_prev_in_buf)) {
	64	+ if (gdbstub_prev_in_buf_pos < gdbstub_use_prev_in_buf)
	65	+ return remcom_in_buffer[gdbstub_prev_in_buf_pos++];
	66	+ else
	67	+ gdbstub_use_prev_in_buf = 0;
	68	+ }
	69	+
61	70	/* poll any additional I/O interfaces that are defined */
62	71	while (ret < 0)
63	72	for (i = 0; kdb_poll_funcs[i] != NULL; i++) {
@@ -109,7 +118,6 @@ static void get_packet(char *buffer) · 45 unmodified lines
109	118	buffer[count] = ch;
110	119	count = count + 1;
111	120	}
112		− buffer[count] = 0;
113	121
114	122	if (ch == '#') {
115	123	xmitcsum = hex_to_bin(gdbstub_read_wait()) << 4;
@@ -124,6 +132,7 @@ static void get_packet(char *buffer) · 8 unmodified lines
124	132	if (dbg_io_ops->flush)
125	133	dbg_io_ops->flush();
126	134	}
	135	+ buffer[count] = 0;
127	136	} while (checksum != xmitcsum);
128	137	}
129	138
@@ -1082,12 +1091,11 @@ int gdbstub_state(struct kgdb_state ks, char cmd) · 952 unmodified lines
1082	1091	case 'c':
1083	1092	strcpy(remcom_in_buffer, cmd);
1084	1093	return 0;
1085		− case '?':
1086		− gdb_cmd_status(ks);
1087		− break;
1088		− case '\0':
1089		− strcpy(remcom_out_buffer, "");
1090		− break;
	1094	+ case '$':
	1095	+ strcpy(remcom_in_buffer, cmd);
	1096	+ gdbstub_use_prev_in_buf = strlen(remcom_in_buffer);
	1097	+ gdbstub_prev_in_buf_pos = 0;
	1098	+ return 0;
1091	1099	}
1092	1100	dbg_io_ops->write_char('+');
1093	1101	put_packet(remcom_out_buffer);

kernel/debug/kdb/kdb_debugger.c+7−10

@@ -30,6 +30,8 @@ EXPORT_SYMBOL_GPL(kdb_poll_funcs); · 29 unmodified lines
30	30	int kdb_poll_idx = 1;
31	31	EXPORT_SYMBOL_GPL(kdb_poll_idx);
32	32
	33	+static struct kgdb_state *kdb_ks;
	34	+
33	35	int kdb_stub(struct kgdb_state *ks)
34	36	{
35	37	int error = 0;
@@ -39,6 +41,7 @@ int kdb_stub(struct kgdb_state *ks) · 3 unmodified lines
39	41	kdb_dbtrap_t db_result = KDB_DB_NOBPT;
40	42	int i;
41	43
	44	+ kdb_ks = ks;
42	45	if (KDB_STATE(REENTRY)) {
43	46	reason = KDB_REASON_SWITCH;
44	47	KDB_STATE_CLEAR(REENTRY);
@@ -124,16 +127,6 @@ int kdb_stub(struct kgdb_state *ks) · 79 unmodified lines
124	127	kdbnearsym_cleanup();
125	128	if (error == KDB_CMD_KGDB) {
126	129	if (KDB_STATE(DOING_KGDB) \|\| KDB_STATE(DOING_KGDB2)) {
127		− /*
128		− * This inteface glue which allows kdb to transition in into
129		− * the gdb stub. In order to do this the '?' or '' gdb serial
130		− * packet response is processed here. And then control is
131		− * passed to the gdbstub.
132		− */
133		− if (KDB_STATE(DOING_KGDB))
134		− gdbstub_state(ks, "?");
135		− else
136		− gdbstub_state(ks, "");
137	130	KDB_STATE_CLEAR(DOING_KGDB);
138	131	KDB_STATE_CLEAR(DOING_KGDB2);
139	132	}
@@ -166,3 +159,7 @@ int kdb_stub(struct kgdb_state *ks) · 26 unmodified lines
166	159	return kgdb_info[ks->cpu].ret_state;
167	160	}
168	161
	162	+void kdb_gdb_state_pass(char *buf)
	163	+{
	164	+ gdbstub_state(kdb_ks, buf);
	165	+}

kernel/debug/kdb/kdb_io.c+6−4

@@ -35,8 +35,8 @@ static void kgdb_transition_check(char *buffer) · 34 unmodified lines
35	35	{
36	36	int slen = strlen(buffer);
37	37	if (strncmp(buffer, "$?#3f", slen) != 0 &&
38		− strncmp(buffer, "$qSupported#37", slen) != 0 &&
39		− strncmp(buffer, "+$qSupported#37", slen) != 0) {
	38	+ strncmp(buffer, "$qSupported", slen) != 0 &&
	39	+ strncmp(buffer, "+$qSupported", slen) != 0) {
40	40	KDB_STATE_SET(KGDB_TRANS);
41	41	kdb_printf("%s", buffer);
42	42	}
@@ -390,12 +390,14 @@ poll_again: · 347 unmodified lines
390	390	/* Special escape to kgdb */
391	391	if (lastchar - buffer >= 5 &&
392	392	strcmp(lastchar - 5, "$?#3f") == 0) {
	393	+ kdb_gdb_state_pass(lastchar - 5);
393	394	strcpy(buffer, "kgdb");
394	395	KDB_STATE_SET(DOING_KGDB);
395	396	return buffer;
396	397	}
397		− if (lastchar - buffer >= 14 &&
398		− strcmp(lastchar - 14, "$qSupported#37") == 0) {
	398	+ if (lastchar - buffer >= 11 &&
	399	+ strcmp(lastchar - 11, "$qSupported") == 0) {
	400	+ kdb_gdb_state_pass(lastchar - 11);
399	401	strcpy(buffer, "kgdb");
400	402	KDB_STATE_SET(DOING_KGDB2);
401	403	return buffer;

kernel/debug/kdb/kdb_private.h+1−0

@@ -218,6 +218,7 @@ extern void kdb_print_nameval(const char *name, unsigned long val); · 217 unmodified lines
218	218	extern void kdb_send_sig_info(struct task_struct p, struct siginfo info);
219	219	extern void kdb_meminfo_proc_show(void);
220	220	extern char kdb_getstr(char , size_t, char *);
	221	+extern void kdb_gdb_state_pass(char *buf);
221	222
222	223	/* Defines for kdb_symbol_print */
223	224	#define KDB_SP_SPACEB 0x0001 /* Space before string */

kdb,kgdb: Implement switch and pass buffer from kdb -> gdb

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