[src/trunk]: src/sys/arch Revert jdolecek's changes related to FXSAVE. They j...

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

details:   https://anonhg.NetBSD.org/src/rev/c255088a51be
branches:  trunk
changeset: 833361:c255088a51be
user:      maxv <maxv%NetBSD.org@localhost>
date:      Fri Jun 22 06:22:37 2018 +0000

description:
Revert jdolecek's changes related to FXSAVE. They just didn't make any
sense and were trying to hide a real bug, which is, that there is for some
reason a wrong stack alignment that causes FXSAVE to fault in
fpuinit_mxcsr_mask. As seen in current-users@ yesterday, rdi % 16 = 8. And
as seen several months ago, as well.

The rest of the changes in XSAVE are wrong too, but I'll let him fix these
ones.

diffstat:

 sys/arch/x86/include/fpu.h |   4 ++--
 sys/arch/x86/x86/cpu.c     |   6 +++---
 sys/arch/x86/x86/fpu.c     |  16 +++++++---------
 sys/arch/xen/x86/cpu.c     |   7 +++----
 4 files changed, 15 insertions(+), 18 deletions(-)

diffs (118 lines):

diff -r 74b52844a389 -r c255088a51be sys/arch/x86/include/fpu.h
--- a/sys/arch/x86/include/fpu.h        Fri Jun 22 04:41:57 2018 +0000
+++ b/sys/arch/x86/include/fpu.h        Fri Jun 22 06:22:37 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fpu.h,v 1.11 2018/06/20 20:43:20 jdolecek Exp $        */
+/*     $NetBSD: fpu.h,v 1.12 2018/06/22 06:22:37 maxv Exp $    */
 
 #ifndef        _X86_FPU_H_
 #define        _X86_FPU_H_
@@ -12,7 +12,7 @@
 struct trapframe;
 
 void fpuinit(struct cpu_info *);
-void fpuinit_mxcsr_mask(bool);
+void fpuinit_mxcsr_mask(void);
 void fpusave_lwp(struct lwp *, bool);
 void fpusave_cpu(bool);
 
diff -r 74b52844a389 -r c255088a51be sys/arch/x86/x86/cpu.c
--- a/sys/arch/x86/x86/cpu.c    Fri Jun 22 04:41:57 2018 +0000
+++ b/sys/arch/x86/x86/cpu.c    Fri Jun 22 06:22:37 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpu.c,v 1.157 2018/06/20 20:43:21 jdolecek Exp $       */
+/*     $NetBSD: cpu.c,v 1.158 2018/06/22 06:22:37 maxv Exp $   */
 
 /*
  * Copyright (c) 2000-2012 NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.157 2018/06/20 20:43:21 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.158 2018/06/22 06:22:37 maxv Exp $");
 
 #include "opt_ddb.h"
 #include "opt_mpbios.h"                /* for MPDEBUG */
@@ -638,7 +638,7 @@
        }
 
        if (x86_fpu_save >= FPU_SAVE_FXSAVE) {
-               fpuinit_mxcsr_mask(true);
+               fpuinit_mxcsr_mask();
        }
 
        /* If xsave is enabled, enable all fpu features */
diff -r 74b52844a389 -r c255088a51be sys/arch/x86/x86/fpu.c
--- a/sys/arch/x86/x86/fpu.c    Fri Jun 22 04:41:57 2018 +0000
+++ b/sys/arch/x86/x86/fpu.c    Fri Jun 22 06:22:37 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fpu.c,v 1.41 2018/06/20 20:43:21 jdolecek Exp $        */
+/*     $NetBSD: fpu.c,v 1.42 2018/06/22 06:22:37 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 1.41 2018/06/20 20:43:21 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fpu.c,v 1.42 2018/06/22 06:22:37 maxv Exp $");
 
 #include "opt_multiprocessor.h"
 
@@ -237,14 +237,9 @@
  * Get the value of MXCSR_MASK supported by the CPU.
  */
 void
-fpuinit_mxcsr_mask(bool has_fxsave)
+fpuinit_mxcsr_mask(void)
 {
-
-       if (!has_fxsave) {
-               x86_fpu_mxcsr_mask = __INITIAL_MXCSR_MASK__;
-               return;
-       }
-
+#ifndef XEN
        union savefpu fpusave __aligned(16);
        u_long psl;
 
@@ -267,6 +262,9 @@
        } else {
                x86_fpu_mxcsr_mask = fpusave.sv_xmm.fx_mxcsr_mask;
        }
+#else
+       x86_fpu_mxcsr_mask = __INITIAL_MXCSR_MASK__;
+#endif
 }
 
 static void
diff -r 74b52844a389 -r c255088a51be sys/arch/xen/x86/cpu.c
--- a/sys/arch/xen/x86/cpu.c    Fri Jun 22 04:41:57 2018 +0000
+++ b/sys/arch/xen/x86/cpu.c    Fri Jun 22 06:22:37 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpu.c,v 1.119 2018/06/20 20:43:20 jdolecek Exp $       */
+/*     $NetBSD: cpu.c,v 1.120 2018/06/22 06:22:37 maxv Exp $   */
 
 /*-
  * Copyright (c) 2000 The NetBSD Foundation, Inc.
@@ -65,7 +65,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.119 2018/06/20 20:43:20 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.120 2018/06/22 06:22:37 maxv Exp $");
 
 #include "opt_ddb.h"
 #include "opt_multiprocessor.h"
@@ -564,8 +564,7 @@
        }
 
        if (x86_fpu_save >= FPU_SAVE_FXSAVE) {
-               /* XXX fxsave() faults on Xen with no-xsave flag, why? */
-               fpuinit_mxcsr_mask((cr4 & CR4_OSXSAVE) != 0);
+               fpuinit_mxcsr_mask();
        }
 
        /*