[src/trunk]: src/sys/arch/x86/x86 - fix an off-by-one that disallowed adjacen...

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

details:   https://anonhg.NetBSD.org/src/rev/b3a38db389e5
branches:  trunk
changeset: 761006:b3a38db389e5
user:      jmcneill <jmcneill%NetBSD.org@localhost>
date:      Tue Jan 18 17:44:15 2011 +0000

description:
- fix an off-by-one that disallowed adjacent mappings with conflicting
  types from being created
- only allow MTRR_TYPE_WC mappings if the processor supports it

diffstat:

 sys/arch/x86/x86/mtrr_i686.c |  16 ++++++++++++----
 1 files changed, 12 insertions(+), 4 deletions(-)

diffs (51 lines):

diff -r bdaa2b48656f -r b3a38db389e5 sys/arch/x86/x86/mtrr_i686.c
--- a/sys/arch/x86/x86/mtrr_i686.c      Tue Jan 18 17:34:28 2011 +0000
+++ b/sys/arch/x86/x86/mtrr_i686.c      Tue Jan 18 17:44:15 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mtrr_i686.c,v 1.23 2011/01/12 23:52:38 jmcneill Exp $ */
+/*     $NetBSD: mtrr_i686.c,v 1.24 2011/01/18 17:44:15 jmcneill Exp $ */
 
 /*-
  * Copyright (c) 2000 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: mtrr_i686.c,v 1.23 2011/01/12 23:52:38 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: mtrr_i686.c,v 1.24 2011/01/18 17:44:15 jmcneill Exp $");
 
 #include "opt_multiprocessor.h"
 
@@ -481,6 +481,14 @@
            || mtrrp->type > MTRR_TYPE_WB) && (mtrrp->flags & MTRR_VALID))
                return EINVAL;
 
+       /* 
+        * If write-combining is requested, make sure that the WC feature   
+        * is supported by the processor.
+        */
+       if (mtrrp->type == MTRR_TYPE_WC &&
+           !(i686_mtrr_cap & MTRR_I686_CAP_WC_MASK))
+               return ENODEV;
+
        /*
         * Only use fixed ranges < 1M.
         */
@@ -604,7 +612,7 @@
         * XXX could be more sophisticated here by merging ranges.
         */
        low = mtrrp->base;
-       high = low + mtrrp->len;
+       high = low + mtrrp->len - 1;
        freep = NULL;
        for (i = 0; i < i686_mtrr_vcnt; i++) {
                if (!(mtrr_var[i].flags & MTRR_VALID)) {
@@ -612,7 +620,7 @@
                        continue;
                }
                curlow = mtrr_var[i].base;
-               curhigh = curlow + mtrr_var[i].len;
+               curhigh = curlow + mtrr_var[i].len - 1;
                if (low == curlow && high == curhigh &&
                    (!(mtrr_var[i].flags & MTRR_PRIVATE) ||
                     ((mtrrp->flags & MTRR_PRIVATE) && (p != NULL) &&