From 22cad5de7bcd7b3dd5d6c90fbfdc9de40c37b59a Mon Sep 17 00:00:00 2001
From: maxv <maxv@NetBSD.org>
Date: Wed, 28 Mar 2018 19:56:40 +0000
Subject: [PATCH] The call to svs_lwp_switch can clobber %rdi/%rsi, so restore
 them before calling speculation_barrier.

---
 sys/arch/amd64/amd64/locore.S | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/sys/arch/amd64/amd64/locore.S b/sys/arch/amd64/amd64/locore.S
index 7095910bf77e..d5428a382cd9 100644
--- a/sys/arch/amd64/amd64/locore.S
+++ b/sys/arch/amd64/amd64/locore.S
@@ -1,4 +1,4 @@
-/*	$NetBSD: locore.S,v 1.160 2018/03/28 16:02:49 maxv Exp $	*/
+/*	$NetBSD: locore.S,v 1.161 2018/03/28 19:56:40 maxv Exp $	*/
 
 /*
  * Copyright-o-rama!
@@ -1096,6 +1096,10 @@ ENTRY(cpu_switchto)
 	callq	_C_LABEL(svs_lwp_switch)
 .Lskip_svs:
 	popq	%rdx
+
+	/* Restore rdi/rsi for speculation_barrier */
+	movq	%r13,%rdi
+	movq	%r12,%rsi
 #endif
 
 	pushq	%rdx