Fixed a longstanding scheduling bug. ASTs and softclock interrupts were

not masked during handling of shared PCI interrupts.  This resulted in
ASTs sometimes being discarded and softclock interrupts sometimes being
handled prematurely (sometimes = quite often on systems with shared PCI
interrupts, never on other systems).

Debugged by:	gibbs and other people at plutotech.com
PR:		6944, maybe 12381

1 files changed, 13 insertions, 12 deletions

diff --git a/sys/i386/isa/nmi.c b/sys/i386/isa/nmi.c
index 7076748..3a214a9 100644
--- a/sys/i386/isa/nmi.c
+++ b/sys/i386/isa/nmi.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)isa.c	7.2 (Berkeley) 5/13/91
- *	$Id: intr_machdep.c,v 1.21 1999/05/04 21:18:20 dfr Exp $
+ *	$Id: intr_machdep.c,v 1.22 1999/05/22 09:39:31 peter Exp $
  */
 /*
  * This file contains an aggregated module marked:
@@ -313,7 +313,7 @@ update_intr_masks(void)
 		maskptr = intr_mptr[intr];
 		if (!maskptr)
 			continue;
-		*maskptr |= 1 << intr;
+		*maskptr |= SWI_CLOCK_MASK | (1 << intr);
 		mask = *maskptr;
 		if (mask != intr_mask[intr]) {
 #if 0
@@ -400,7 +400,7 @@ icu_setup(int intr, inthand2_t *handler, void *arg, u_int *maskptr, int flags)
 	disable_intr();
 	intr_handler[intr] = handler;
 	intr_mptr[intr] = maskptr;
-	intr_mask[intr] = mask | (1 << intr);
+	intr_mask[intr] = mask | SWI_CLOCK_MASK | (1 << intr);
 	intr_unit[intr] = arg;
 #ifdef FAST_HI
 	if (flags & INTR_FAST) {
@@ -506,7 +506,7 @@ icu_unset(intr, handler)
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- * $Id: intr_machdep.c,v 1.21 1999/05/04 21:18:20 dfr Exp $
+ * $Id: intr_machdep.c,v 1.22 1999/05/22 09:39:31 peter Exp $
  *
  */
 
@@ -531,22 +531,23 @@ typedef struct isarec {
 static isarec *isareclist[ICU_LEN];
 
 /*
- * The interrupt multiplexer calls each of the handlers in turn,
- * and applies the associated interrupt mask to "cpl", which is
- * defined as a ".long" in /sys/i386/isa/ipl.s
+ * The interrupt multiplexer calls each of the handlers in turn.  The
+ * ipl is initially quite low.  It is raised as necessary for each call
+ * and lowered after the call.  Thus out of order handling is possible
+ * even for interrupts of the same type.  This is probably no more
+ * harmful than out of order handling in general (not harmful except
+ * for real time response which we don't support anyway).
  */
-
 static void
 intr_mux(void *arg)
 {
-	intrec *p = arg;
-	int oldspl;
+	intrec *p;
+	intrmask_t oldspl;
 
-	while (p != NULL) {
+	for (p = arg; p != NULL; p = p->next) {
 		oldspl = splq(p->mask);
 		p->handler(p->argument);
 		splx(oldspl);
-		p = p->next;
 	}
 }