[src/trunk]: src/sys/arch Revert the rest of jdolecek's changes. This puts us...

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

details:   https://anonhg.NetBSD.org/src/rev/3b25200360d2
branches:  trunk
changeset: 833391:3b25200360d2
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sat Jun 23 09:51:34 2018 +0000

description:
Revert the rest of jdolecek's changes. This puts us back in a clean,
sensical state.

diffstat:

 sys/arch/x86/x86/identcpu.c |   9 ++++++-
 sys/arch/xen/x86/cpu.c      |  48 +++-----------------------------------------
 2 files changed, 11 insertions(+), 46 deletions(-)

diffs (116 lines):

diff -r 2ff25a78ad9c -r 3b25200360d2 sys/arch/x86/x86/identcpu.c
--- a/sys/arch/x86/x86/identcpu.c       Sat Jun 23 07:21:00 2018 +0000
+++ b/sys/arch/x86/x86/identcpu.c       Sat Jun 23 09:51:34 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: identcpu.c,v 1.74 2018/06/22 23:00:54 christos Exp $   */
+/*     $NetBSD: identcpu.c,v 1.75 2018/06/23 09:51:34 maxv Exp $       */
 
 /*-
  * Copyright (c) 1999, 2000, 2001, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: identcpu.c,v 1.74 2018/06/22 23:00:54 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: identcpu.c,v 1.75 2018/06/23 09:51:34 maxv Exp $");
 
 #include "opt_xen.h"
 
@@ -813,7 +813,12 @@
        if (descs[2] > 512)
                x86_fpu_save_size = descs[2];
 
+#ifdef XEN
+       /* Don't use xsave, force fxsave with x86_xsave_features = 0. */
+       x86_fpu_save = FPU_SAVE_FXSAVE;
+#else
        x86_xsave_features = (uint64_t)descs[3] << 32 | descs[0];
+#endif
 }
 
 void
diff -r 2ff25a78ad9c -r 3b25200360d2 sys/arch/xen/x86/cpu.c
--- a/sys/arch/xen/x86/cpu.c    Sat Jun 23 07:21:00 2018 +0000
+++ b/sys/arch/xen/x86/cpu.c    Sat Jun 23 09:51:34 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpu.c,v 1.120 2018/06/22 06:22:37 maxv Exp $   */
+/*     $NetBSD: cpu.c,v 1.121 2018/06/23 09:51:34 maxv Exp $   */
 
 /*-
  * Copyright (c) 2000 The NetBSD Foundation, Inc.
@@ -65,7 +65,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.120 2018/06/22 06:22:37 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.121 2018/06/23 09:51:34 maxv Exp $");
 
 #include "opt_ddb.h"
 #include "opt_multiprocessor.h"
@@ -527,64 +527,24 @@
 void
 cpu_init(struct cpu_info *ci)
 {
-       uint32_t cr4 = 0;
 
        /*
         * If we have FXSAVE/FXRESTOR, use them.
         */
        if (cpu_feature[0] & CPUID_FXSR) {
-               cr4 |= CR4_OSFXSR;
+               lcr4(rcr4() | CR4_OSFXSR);
 
                /*
                 * If we have SSE/SSE2, enable XMM exceptions.
                 */
                if (cpu_feature[0] & (CPUID_SSE|CPUID_SSE2))
-                       cr4 |= CR4_OSXMMEXCPT;
-       }
-
-       /*
-        * Xen kernel sets OSXSAVE if appropriate for the hardware,
-        * or disables it with no-xsave flag or due to security bugs with
-        * particular CPUs.
-        * If it's unset, it also means the xrstor() et.al. are privileged
-        * and trigger supervisor trap. So, contrary to what regular x86
-        * does, here we only set CR4_OSXSAVE if the feature is already
-        * enabled according to CPUID.
-        */
-       if (cpu_feature[1] & CPUID2_OSXSAVE)
-               cr4 |= CR4_OSXSAVE;
-       else {
-               x86_xsave_features = 0;
-               x86_fpu_save = FPU_SAVE_FXSAVE;
-       }
-
-       if (cr4) {
-               cr4 |= rcr4();
-               lcr4(cr4);
+                       lcr4(rcr4() | CR4_OSXMMEXCPT);
        }
 
        if (x86_fpu_save >= FPU_SAVE_FXSAVE) {
                fpuinit_mxcsr_mask();
        }
 
-       /*
-        * Changing CR4 register may change cpuid values. For example, setting
-        * CR4_OSXSAVE sets CPUID2_OSXSAVE. The CPUID2_OSXSAVE is in
-        * ci_feat_val[1], so update it.
-        * XXX Other than ci_feat_val[1] might be changed.
-        */
-       if (cpuid_level >= 1) {
-               u_int descs[4];
-
-               x86_cpuid(1, descs);
-               ci->ci_feat_val[1] = descs[2];
-       }
-
-       /* If xsave is enabled, enable all fpu features */
-       if (cr4 & CR4_OSXSAVE) {
-               wrxcr(0, x86_xsave_features & XCR0_FPU);
-       }
-
        atomic_or_32(&ci->ci_flags, CPUF_RUNNING);
 }