From 2d7e563c39c796a5b720935e955a2ce751cfabcc Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Thu, 5 Apr 2018 11:03:21 +0000
Subject: [PATCH] Fix ERESTART for lcall $7,$0 syscalls.

The lcall trampoline enters kernel by int $0x80, which sets up invalid
length of the instruction for %rip rewind.

Reviewed by:	bde
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
---
 sys/amd64/ia32/ia32_syscall.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sys/amd64/ia32/ia32_syscall.c b/sys/amd64/ia32/ia32_syscall.c
index b8275b3fe7e..f5ee91cbf5d 100644
--- a/sys/amd64/ia32/ia32_syscall.c
+++ b/sys/amd64/ia32/ia32_syscall.c
@@ -146,6 +146,7 @@ ia32_fetch_syscall_args(struct thread *td)
 		frame->tf_rip = eip;
 		frame->tf_cs = cs;
 		frame->tf_rsp += 2 * sizeof(u_int32_t);
+		frame->tf_err = 7;		/* size of lcall $7,$0 */
 	}
 #endif