kgdb,8250,pl011: Return immediately from console poll

The design of the kdb shell requires that every device that can
provide input to kdb have a polling routine that exits immediately if
there is no character available.  This is required in order to get the
page scrolling mechanism working.

Changing the kernel debugger I/O API to require all polling character
routines to exit immediately if there is no data allows the kernel
debugger to process multiple input channels.

NO_POLL_CHAR will be the return code to the polling routine when ever
there is no character available.

CC: linux-serial@vger.kernel.org
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c
index f024c0c4b8c4..bf6e8270e957 100644
--- a/kernel/debug/kdb/kdb_debugger.c
+++ b/kernel/debug/kdb/kdb_debugger.c
@@ -20,7 +20,15 @@
 get_char_func kdb_poll_funcs[] = {
         dbg_io_get_char,
         NULL,
+        NULL,
+        NULL,
+        NULL,
+        NULL,
 };
+EXPORT_SYMBOL_GPL(kdb_poll_funcs);
+
+int kdb_poll_idx = 1;
+EXPORT_SYMBOL_GPL(kdb_poll_idx);
 
 int kdb_stub(struct kgdb_state *ks)
 {
@@ -85,6 +93,7 @@ int kdb_stub(struct kgdb_state *ks)
         kdb_bp_remove();
         KDB_STATE_CLEAR(DOING_SS);
         KDB_STATE_CLEAR(DOING_SSB);
+        KDB_STATE_SET(PAGER);
         /* zero out any offline cpu data */
         for_each_present_cpu(i) {
                 if (!cpu_online(i)) {
@@ -112,6 +121,7 @@ int kdb_stub(struct kgdb_state *ks)
         kdb_initial_cpu = -1;
         kdb_current_task = NULL;
         kdb_current_regs = NULL;
+        KDB_STATE_CLEAR(PAGER);
         kdbnearsym_cleanup();
         if (error == KDB_CMD_KGDB) {
                 if (KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)) {