Module Name: src
Committed By: ad
Date: Sun May 17 12:12:22 UTC 2020
Modified Files:
src/sys/arch/i386/i386: spl.S
Log Message:
comments
To generate a diff of this commit:
cvs rdiff -u -r1.54 -r1.55 src/sys/arch/i386/i386/spl.S
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/i386/i386/spl.S
diff -u src/sys/arch/i386/i386/spl.S:1.54 src/sys/arch/i386/i386/spl.S:1.55
--- src/sys/arch/i386/i386/spl.S:1.54 Fri May 1 09:40:47 2020
+++ src/sys/arch/i386/i386/spl.S Sun May 17 12:12:22 2020
@@ -1,7 +1,7 @@
-/* $NetBSD: spl.S,v 1.54 2020/05/01 09:40:47 maxv Exp $ */
+/* $NetBSD: spl.S,v 1.55 2020/05/17 12:12:22 ad Exp $ */
/*
- * Copyright (c) 1998, 2007, 2008 The NetBSD Foundation, Inc.
+ * Copyright (c) 1998, 2007, 2008, 2020 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
@@ -30,7 +30,7 @@
*/
#include <machine/asm.h>
-__KERNEL_RCSID(0, "$NetBSD: spl.S,v 1.54 2020/05/01 09:40:47 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: spl.S,v 1.55 2020/05/17 12:12:22 ad Exp $");
#include "opt_ddb.h"
#include "opt_spldebug.h"
@@ -359,7 +359,13 @@ IDTVEC(softintr)
CLI(%ecx)
movl L_PCB(%esi),%ecx
movl PCB_ESP(%ecx),%esp
- xchgl %esi,CPUVAR(CURLWP) /* must be globally visible */
+
+ /*
+ * for non-interlocked mutex release to work safely the change
+ * to ci_curlwp must not languish in the store buffer. therefore
+ * we use XCHG and not MOV here. see kern_mutex.c.
+ */
+ xchgl %esi,CPUVAR(CURLWP) /* restore ci_curlwp */
popl %edi /* unwind switchframe */
popl %esi
addl $8,%esp
