[src/trunk]: src/sys/arch/x86/x86 Always set XCR0_X87, to force a reload of C...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d01b8fadd835
branches:  trunk
changeset: 357282:d01b8fadd835
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sat Nov 04 07:38:42 2017 +0000

description:
Always set XCR0_X87, to force a reload of CW. That's needed for compat
options where fx_cw is not the standard fpu value.

diffstat:

 sys/arch/x86/x86/fpu.c |  11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diffs (32 lines):

diff -r cc6f1f4d50f2 -r d01b8fadd835 sys/arch/x86/x86/fpu.c
--- a/sys/arch/x86/x86/fpu.c    Sat Nov 04 07:35:00 2017 +0000
+++ b/sys/arch/x86/x86/fpu.c    Sat Nov 04 07:38:42 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fpu.c,v 1.22 2017/11/04 07:35:00 maxv Exp $    */
+/*     $NetBSD: fpu.c,v 1.23 2017/11/04 07:38:42 maxv Exp $    */
 
 /*
  * Copyright (c) 2008 The NetBSD Foundation, Inc.  All
@@ -96,7 +96,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fpu.c,v 1.22 2017/11/04 07:35:00 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fpu.c,v 1.23 2017/11/04 07:38:42 maxv Exp $");
 
 #include "opt_multiprocessor.h"
 
@@ -557,6 +557,13 @@
                fpu_save->sv_xmm.fx_mxcsr = __INITIAL_MXCSR__;
                fpu_save->sv_xmm.fx_mxcsr_mask = x86_fpu_mxcsr_mask;
                fpu_save->sv_xmm.fx_cw = x87_cw;
+
+               /* Force a reload of CW */
+               if (x86_fpu_save == FPU_SAVE_XSAVE ||
+                   x86_fpu_save == FPU_SAVE_XSAVEOPT) {
+                       fpu_save->sv_xsave_hdr.xsh_xstate_bv |=
+                           XCR0_X87;
+               }
        } else {
                memset(&fpu_save->sv_87, 0, x86_fpu_save_size);
                fpu_save->sv_87.s87_tw = 0xffff;