This patch is mortly art's work and was done *a year* ago. Art wants to thank

everyone for the prompt review and ok of this work ;-)  Yeah, that includes me
too, or maybe especially me.  I am sorry.

Change the sched_lock to a mutex. This fixes, among other things, the infamous
"telnet localhost &" problem.  The real bug in that case was that the sched_lock
which is by design a non-recursive lock, was recursively acquired, and not
enough releases made us hold the lock in the idle loop, blocking scheduling
on the other processors.  Some of the other processors would hold the biglock though,
which made it impossible for cpu 0 to enter the kernel...  A nice deadlock.
Let me just say debugging this for days just to realize that it was all fixed
in an old diff noone ever ok'd was somewhat of an anti-climax.

This diff also changes splsched to be correct for all our architectures.

3 files changed, 4 insertions, 14 deletions

diff --git a/sys/arch/i386/i386/locore.s b/sys/arch/i386/i386/locore.s
index a067a9b3ca9..df652a97c19 100644
--- a/sys/arch/i386/i386/locore.s
+++ b/sys/arch/i386/i386/locore.s
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.s,v 1.87 2005/05/25 22:50:25 beck Exp $	*/
+/*	$OpenBSD: locore.s,v 1.88 2005/05/25 23:17:47 niklas Exp $	*/
 /*	$NetBSD: locore.s,v 1.145 1996/05/03 19:41:19 christos Exp $	*/
 
 /*-
@@ -1616,7 +1616,6 @@ ENTRY(idle_loop)
 	jmp	_C_LABEL(idle_loop)
 
 ENTRY(idle_exit)
-	movl	$IPL_HIGH,CPL		# splhigh
 	sti
 #if defined(MULTIPROCESSOR) || defined(LOCKDEBUG)	
 	call	_C_LABEL(sched_lock_idle)
diff --git a/sys/arch/i386/i386/trap.c b/sys/arch/i386/i386/trap.c
index e0aeb203bfb..98d21021725 100644
--- a/sys/arch/i386/i386/trap.c
+++ b/sys/arch/i386/i386/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.67 2004/12/06 20:12:24 miod Exp $	*/
+/*	$OpenBSD: trap.c,v 1.68 2005/05/25 23:17:47 niklas Exp $	*/
 /*	$NetBSD: trap.c,v 1.95 1996/05/05 06:50:02 mycroft Exp $	*/
 
 /*-
@@ -451,15 +451,6 @@ trap(frame)
 	case T_PAGEFLT:			/* allow page faults in kernel mode */
 		if (p == 0 || p->p_addr == 0)
 			goto we_re_toast;
-#ifdef LOCKDEBUG
-		/* If we page-fault while in scheduler, we're doomed. */
-#ifdef notyet
-		if (simple_lock_held(&sched_lock))
-#else
-		if (__mp_lock_held(&sched_lock))
-#endif
-			goto we_re_toast;
-#endif
 
 		pcb = &p->p_addr->u_pcb;
 #if 0
diff --git a/sys/arch/i386/include/intrdefs.h b/sys/arch/i386/include/intrdefs.h
index c2c998b76b3..2cf218fc765 100644
--- a/sys/arch/i386/include/intrdefs.h
+++ b/sys/arch/i386/include/intrdefs.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: intrdefs.h,v 1.2 2004/06/13 21:49:16 niklas Exp $	*/
+/*	$OpenBSD: intrdefs.h,v 1.3 2005/05/25 23:17:47 niklas Exp $	*/
 /*	$NetBSD: intrdefs.h,v 1.2 2003/05/04 22:01:56 fvdl Exp $	*/
 
 #ifndef _i386_INTRDEFS_H
@@ -66,8 +66,8 @@
 #define IPL_IMP		IPL_VM		/* XXX - should not be here. */
 #define	IPL_AUDIO	MAKEIPL(7)	/* audio */
 #define	IPL_CLOCK	MAKEIPL(8)	/* clock */
-#define	IPL_SCHED	IPL_CLOCK
 #define	IPL_STATCLOCK	MAKEIPL(9)	/* statclock */
+#define	IPL_SCHED	IPL_STATCLOCK
 #define	IPL_HIGH	MAKEIPL(9)	/* everything */
 #define	IPL_IPI		MAKEIPL(10)	/* interprocessor interrupt */