[src/trunk]: src/sys/arch/x86/x86 Remove #ifdef XEN (Xen has its own cpu.c), ...

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

details:   https://anonhg.NetBSD.org/src/rev/078a5434d7c6
branches:  trunk
changeset: 360526:078a5434d7c6
user:      maxv <maxv%NetBSD.org@localhost>
date:      Thu Mar 15 09:17:31 2018 +0000

description:
Remove #ifdef XEN (Xen has its own cpu.c), and add a comment.

diffstat:

 sys/arch/x86/x86/cpu.c |  15 +++++++++------
 1 files changed, 9 insertions(+), 6 deletions(-)

diffs (47 lines):

diff -r f3f06e47ad9d -r 078a5434d7c6 sys/arch/x86/x86/cpu.c
--- a/sys/arch/x86/x86/cpu.c    Thu Mar 15 08:15:21 2018 +0000
+++ b/sys/arch/x86/x86/cpu.c    Thu Mar 15 09:17:31 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpu.c,v 1.151 2018/03/14 17:40:41 maxv Exp $   */
+/*     $NetBSD: cpu.c,v 1.152 2018/03/15 09:17:31 maxv Exp $   */
 
 /*
  * Copyright (c) 2000-2012 NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.151 2018/03/14 17:40:41 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.152 2018/03/15 09:17:31 maxv Exp $");
 
 #include "opt_ddb.h"
 #include "opt_mpbios.h"                /* for MPDEBUG */
@@ -1338,8 +1338,6 @@
        x86_send_ipi(ci, 0);
 }
 
-#if !defined(XEN)
-
 /* --------------------------------------------------------------------- */
 
 /*
@@ -1364,6 +1362,13 @@
                /* TODO: detect MITIGATION_INTEL_IBRS */
                mitigation_method = MITIGATION_NONE;
        } else if (cpu_vendor == CPUVENDOR_AMD) {
+               /*
+                * The AMD Family 10h manual documents the IC_CFG.DIS_IND bit.
+                * This bit disables the Indirect Branch Predictor.
+                *
+                * Families 12h and 16h are believed to have this bit too, but
+                * their manuals don't document it.
+                */
                switch (CPUID_TO_FAMILY(ci->ci_signature)) {
                case 0x10:
                case 0x12:
@@ -1504,5 +1509,3 @@
 
        return error;
 }
-
-#endif