Module Name: src
Committed By: ad
Date: Sun May 17 12:11:11 UTC 2020
Modified Files:
src/sys/arch/amd64/amd64: spl.S
Log Message:
comments
To generate a diff of this commit:
cvs rdiff -u -r1.45 -r1.46 src/sys/arch/amd64/amd64/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/amd64/amd64/spl.S
diff -u src/sys/arch/amd64/amd64/spl.S:1.45 src/sys/arch/amd64/amd64/spl.S:1.46
--- src/sys/arch/amd64/amd64/spl.S:1.45 Sat May 2 11:12:49 2020
+++ src/sys/arch/amd64/amd64/spl.S Sun May 17 12:11:11 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: spl.S,v 1.45 2020/05/02 11:12:49 maxv Exp $ */
+/* $NetBSD: spl.S,v 1.46 2020/05/17 12:11:11 ad Exp $ */
/*
* Copyright (c) 2003 Wasabi Systems, Inc.
@@ -157,7 +157,12 @@ IDTVEC(softintr)
movq L_PCB(%r15),%rcx
movq PCB_RSP(%rcx),%rsp
- xchgq %r15,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.
+ */
+ xchgq %r15,CPUVAR(CURLWP) /* restore curlwp */
popq %r15 /* unwind switchframe */
addq $(5 * 8),%rsp
jmp *%r13 /* back to Xspllower/Xdoreti */
