From ab4a10afba640863e864d0e672716a5fbfb49e1f Mon Sep 17 00:00:00 2001
From: miod <miod@openbsd.org>
Date: Mon, 18 May 2015 04:06:37 +0000
Subject: [PATCH] Move the logic deciding whether to grab the kernel lock or
 not, deeper in the interrupt logic, making sure the lock is not taken for
 clock interrupts. Tested on aviion and luna88k.

---
 sys/arch/aviion/aviion/av400_machdep.c | 20 +++++++++-----------
 sys/arch/aviion/aviion/av530_machdep.c | 11 +++--------
 sys/arch/luna88k/luna88k/isr.c         | 10 +++++++++-
 sys/arch/luna88k/luna88k/machdep.c     | 13 ++-----------
 4 files changed, 23 insertions(+), 31 deletions(-)

diff --git a/sys/arch/aviion/aviion/av400_machdep.c b/sys/arch/aviion/aviion/av400_machdep.c
index 10a8702d763..661a9fd82d9 100644
--- a/sys/arch/aviion/aviion/av400_machdep.c
+++ b/sys/arch/aviion/aviion/av400_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: av400_machdep.c,v 1.27 2014/11/16 12:30:56 deraadt Exp $	*/
+/*	$OpenBSD: av400_machdep.c,v 1.28 2015/05/18 04:06:37 miod Exp $	*/
 /*
  * Copyright (c) 2006, 2007, Miodrag Vallat.
  *
@@ -646,11 +646,6 @@ av400_intr(struct trapframe *eframe)
 	}
 #endif
 
-#ifdef MULTIPROCESSOR
-	if (old_spl < IPL_SCHED)
-		__mp_lock(&kernel_lock);
-#endif
-
 	/*
 	 * We want to service all interrupts marked in the IST register
 	 * They are all valid because the mask would have prevented them
@@ -724,10 +719,18 @@ av400_intr(struct trapframe *eframe)
 			 */
 			ret = 0;
 			SLIST_FOREACH(intr, list, ih_link) {
+#ifdef MULTIPROCESSOR
+				if (intr->ih_ipl < IPL_CLOCK)
+					__mp_lock(&kernel_lock);
+#endif
 				if (ISSET(intr->ih_flags, INTR_WANTFRAME))
 					ret = (*intr->ih_fn)((void *)eframe);
 				else
 					ret = (*intr->ih_fn)(intr->ih_arg);
+#ifdef MULTIPROCESSOR
+				if (intr->ih_ipl < IPL_CLOCK)
+					__mp_unlock(&kernel_lock);
+#endif
 				if (ret != 0) {
 					intr->ih_count.ec_count++;
 					break;
@@ -764,11 +767,6 @@ av400_intr(struct trapframe *eframe)
 		problems = 0;
 #endif
 
-#ifdef MULTIPROCESSOR
-	if (old_spl < IPL_SCHED)
-		__mp_unlock(&kernel_lock);
-#endif
-
 out:
 	/*
 	 * process any remaining data access exceptions before
diff --git a/sys/arch/aviion/aviion/av530_machdep.c b/sys/arch/aviion/aviion/av530_machdep.c
index a8e7b780b72..10a41461e16 100644
--- a/sys/arch/aviion/aviion/av530_machdep.c
+++ b/sys/arch/aviion/aviion/av530_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: av530_machdep.c,v 1.15 2015/04/25 21:15:08 miod Exp $	*/
+/*	$OpenBSD: av530_machdep.c,v 1.16 2015/05/18 04:06:37 miod Exp $	*/
 /*
  * Copyright (c) 2006, 2007, 2010 Miodrag Vallat.
  *
@@ -570,9 +570,6 @@ av530_intr(struct trapframe *eframe)
 #ifdef DIAGNOSTIC
 	static int problems = 0;
 #endif
-#ifdef MULTIPROCESSOR
-	int need_lock;
-#endif
 
 	cur_mask = ISR_GET_CURRENT_MASK(cpu);
 	cur_exmask = EXISR_GET_CURRENT_MASK(cpu);
@@ -705,9 +702,7 @@ av530_intr(struct trapframe *eframe)
 			ret = 0;
 			SLIST_FOREACH(intr, list, ih_link) {
 #ifdef MULTIPROCESSOR
-				need_lock = intr->ih_ipl < IPL_SCHED &&
-				    intr->ih_ipl != IPL_CLOCK;
-				if (need_lock)
+				if (intr->ih_ipl < IPL_CLOCK)
 					__mp_lock(&kernel_lock);
 #endif
 				if (ISSET(intr->ih_flags, INTR_WANTFRAME))
@@ -715,7 +710,7 @@ av530_intr(struct trapframe *eframe)
 				else
 					ret = (*intr->ih_fn)(intr->ih_arg);
 #ifdef MULTIPROCESSOR
-				if (need_lock)
+				if (intr->ih_ipl < IPL_CLOCK)
 					__mp_unlock(&kernel_lock);
 #endif
 				if (ret != 0) {
diff --git a/sys/arch/luna88k/luna88k/isr.c b/sys/arch/luna88k/luna88k/isr.c
index 3e9fbaf9d57..0a53ed3731a 100644
--- a/sys/arch/luna88k/luna88k/isr.c
+++ b/sys/arch/luna88k/luna88k/isr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: isr.c,v 1.9 2010/12/21 14:56:24 claudio Exp $	*/
+/*	$OpenBSD: isr.c,v 1.10 2015/05/18 04:06:37 miod Exp $	*/
 /*	$NetBSD: isr.c,v 1.5 2000/07/09 08:08:20 nisimura Exp $	*/
 
 /*-
@@ -165,7 +165,15 @@ isrdispatch_autovec(int ipl)
 
 	/* Give all the handlers a chance. */
 	LIST_FOREACH(isr, list, isr_link) {
+#ifdef MULTIPROCESSOR
+		if (isr->isr_ipl < IPL_CLOCK)
+			__mp_lock(&kernel_lock);
+#endif
 		rc = (*isr->isr_func)(isr->isr_arg);
+#ifdef MULTIPROCESSOR
+		if (isr->isr_ipl < IPL_CLOCK)
+			__mp_unlock(&kernel_lock);
+#endif
 		if (rc != 0)
 			isr->isr_count.ec_count++;
 		handled |= rc;
diff --git a/sys/arch/luna88k/luna88k/machdep.c b/sys/arch/luna88k/luna88k/machdep.c
index ba74a8efda5..edf6f9cd92a 100644
--- a/sys/arch/luna88k/luna88k/machdep.c
+++ b/sys/arch/luna88k/luna88k/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.116 2015/02/25 17:41:22 miod Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.117 2015/05/18 04:06:37 miod Exp $	*/
 /*
  * Copyright (c) 1998, 1999, 2000, 2001 Steve Murphree, Jr.
  * Copyright (c) 1996 Nivas Madhur
@@ -868,17 +868,8 @@ luna88k_ext_int(struct trapframe *eframe)
 		case 5:
 		case 4:
 		case 3:
-#ifdef MULTIPROCESSOR
-			if (CPU_IS_PRIMARY(ci)) {
-				if (old_spl < IPL_SCHED)
-					__mp_lock(&kernel_lock);
-#endif
+			if (CPU_IS_PRIMARY(ci))
 				isrdispatch_autovec(cur_int_level);
-#ifdef MULTIPROCESSOR
-				if (old_spl < IPL_SCHED)
-					__mp_unlock(&kernel_lock);
-			}
-#endif
 			break;
 		default:
 			printf("%s: cpu%d level %d interrupt.\n",
-- 
2.20.1