The idle loop is supposed to run with interrupts enabled, and will only

relax the interrupt mask (i.e. spl level).

However, under some unclear circumstances, it will be entered with
interrupts disabled, and thus will loop forever if no process is runnable.

Check the PSR and make sure that interrupts are enabled in this case. This
gets rid of the random freezes, although a better fix would be preferrable...

1 files changed, 20 insertions, 2 deletions

diff --git a/sys/arch/mvme88k/mvme88k/process.S b/sys/arch/mvme88k/mvme88k/process.S
index f3a63118c0c..ae81e62b9ab 100644
--- a/sys/arch/mvme88k/mvme88k/process.S
+++ b/sys/arch/mvme88k/mvme88k/process.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: process.S,v 1.19 2003/08/11 20:45:17 miod Exp $	*/
+/*	$OpenBSD: process.S,v 1.20 2003/08/12 18:06:48 miod Exp $	*/
 /*
  * Copyright (c) 1996 Nivas Madhur
  * All rights reserved.
@@ -42,6 +42,11 @@ ASLOCAL(swchanpanic)
 	align	4
 ASLOCAL(swsrunpanic)
 	string	"switch SRUN %x\0"
+#ifdef DEBUG
+	align	4
+ASLOCAL(boguspsr)
+	string	"Invalid PSR in idle loop 0x%x\n\0"
+#endif
 
 	text
 	align	8
@@ -143,9 +148,22 @@ ASLOCAL(Lidleloop)
 	bcnd	ne0, r7, _ASM_LABEL(Ldoneloop)
 
 ASLOCAL(Lloopchk)			/* if whichqs is zero, keep checking */
-	bsr.n	_C_LABEL(setipl)	/* enable all ints */
+	bsr.n	_C_LABEL(setipl)	/* unmask all ints... */
 	 or	r2, r0, 0
 
+	ldcr	r2, PSR
+	bb0	PSR_INTERRUPT_DISABLE_BIT, r2, 1f
+#ifdef DEBUG
+	or	r3, r2, r0
+	or.u	r2, r0, hi16(_ASM_LABEL(boguspsr))
+	bsr.n	_C_LABEL(printf)
+	 or	r2, r2, lo16(_ASM_LABEL(boguspsr))
+	ldcr	r2, PSR
+#endif
+	clr	r2, r2, 1<PSR_INTERRUPT_DISABLE_BIT>	/* ...and enable them */
+	FLUSH_PIPELINE
+	stcr	r2, PSR
+1:
 	br	_ASM_LABEL(Lidleloop)
 
 ASLOCAL(Ldoneloop)