pxe: use a separate poll thread instead of using an idle thread hook

The idle thread can never sleep, so it's not really safe to do
anything inside it.  Instead, run a separate poll thread at low
priority; we can also do that to poll the serial console if needed.

Overall, the "classic" Syslinux idle handling really should go away
and be replaced by the idle thread.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/core/include/thread.h b/core/include/thread.h
index 7c83b5a9..be3844af 100644
--- a/core/include/thread.h
+++ b/core/include/thread.h
@@ -3,9 +3,16 @@
 
 #include <stddef.h>
 #include <inttypes.h>
+#include <limits.h>
 #include <stdbool.h>
 #include <timer.h>
 
+/* The idle thread runs at this priority */
+#define IDLE_THREAD_PRIORITY	INT_MAX
+
+/* This priority should normally be used for hardware-polling threads */
+#define POLL_THREAD_PRIORITY	(INT_MAX-1)
+
 struct semaphore;
 
 struct thread_list {
@@ -95,6 +102,4 @@ void kill_thread(struct thread *);
 void start_idle_thread(void);
 void test_thread(void);
 
-extern void (*idle_hook)(void);
-
 #endif /* _THREAD_H */