[src/trunk]: src/sys/arch/x86/x86 Disable x86 in-kernel AES temporarily.

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

details:   https://anonhg.NetBSD.org/src/rev/4b0dcc1a6ef5
branches:  trunk
changeset: 936170:4b0dcc1a6ef5
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Mon Jul 20 15:11:29 2020 +0000

description:
Disable x86 in-kernel AES temporarily.

There's a bug in the FPU state handling that it triggers -- likely
limited to the softint path since I've only ever seen it on a system
using wifi configured with WPA2 and CCMP, which uses AES heavily in
softint.

This is to be reverted once we diagnose the bug.  (There is also a
performance regression on wifi with WPA2 and CCMP, which I plan to
fix too once we figure out the FPU state handling bug.)

diffstat:

 sys/arch/x86/x86/identcpu.c |  18 ++++++++++++------
 1 files changed, 12 insertions(+), 6 deletions(-)

diffs (47 lines):

diff -r cce8aa7b4ab6 -r 4b0dcc1a6ef5 sys/arch/x86/x86/identcpu.c
--- a/sys/arch/x86/x86/identcpu.c       Mon Jul 20 15:10:35 2020 +0000
+++ b/sys/arch/x86/x86/identcpu.c       Mon Jul 20 15:11:29 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: identcpu.c,v 1.111 2020/06/29 23:51:35 riastradh Exp $ */
+/*     $NetBSD: identcpu.c,v 1.112 2020/07/20 15:11:29 riastradh 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 1.111 2020/06/29 23:51:35 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: identcpu.c,v 1.112 2020/07/20 15:11:29 riastradh Exp $");
 
 #include "opt_xen.h"
 
@@ -1000,18 +1000,24 @@
                /* Early patch of text segment. */
                x86_patch(true);
 #endif
+               /*
+                * XXX There is a bug with FPU in kernel that we
+                * haven't been able to track down yet, and all of the
+                * accelerated AES code relies on that, so it is
+                * disabled temporarily while we diagnose the bug.
+                */
 #ifdef __x86_64__      /* not yet implemented on i386 */
-               if (cpu_feature[1] & CPUID2_AES)
+               if (0 & cpu_feature[1] & CPUID2_AES)
                        aes_md_init(&aes_ni_impl);
                else
 #endif
-               if (cpu_feature[4] & CPUID_VIA_HAS_ACE)
+               if (0 & cpu_feature[4] & CPUID_VIA_HAS_ACE)
                        aes_md_init(&aes_via_impl);
-               else if (i386_has_sse && i386_has_sse2 &&
+               else if (0 & i386_has_sse && i386_has_sse2 &&
                    (cpu_feature[1] & CPUID2_SSE3) &&
                    (cpu_feature[1] & CPUID2_SSSE3))
                        aes_md_init(&aes_ssse3_impl);
-               else if (i386_has_sse && i386_has_sse2)
+               else if (0 & i386_has_sse && i386_has_sse2)
                        aes_md_init(&aes_sse2_impl);
        } else {
                /*