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

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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>
This commit is contained in:
Jason Wessel 2011-05-23 13:17:41 -05:00
parent 3bdb65ec95
commit f679c4985b
4 changed files with 29 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
kernel/debug/gdbstub.c
View File

@ -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);

17
kernel/debug/kdb/kdb_debugger.c
View File

@ -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);
}

10
kernel/debug/kdb/kdb_io.c
View File

@ -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;

1
kernel/debug/kdb/kdb_private.h
View File

@ -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 */