[coreboot] r1067 - coreboot-v3/arch/x86

svn at coreboot.org svn at coreboot.org
Wed Dec 10 19:34:16 CET 2008

Author: hailfinger
Date: 2008-12-10 19:34:16 +0100 (Wed, 10 Dec 2008)
New Revision: 1067

early_mtrr_init() nukes all MTRRs including those which we use for CAR.
That means if it ever gets called while CAR is active, our stack will be
dropped and mayhem will ensue.
Besides that, it just replicated stage0.S functionality which already
nukes all MTRRs before enabling CAR.

We could move XIP ROM caching from stage0.S to early_mtrr_init(). It
would probably slow down booting a bit, but the amount of asm code would
be reduced.

Thanks to Corey for telling me that early_mtrr_init() broke booting for

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>
Acked-by: Ronald G. Minnich <rminnich at gmail.com>

Modified: coreboot-v3/arch/x86/stage1_mtrr.c
--- coreboot-v3/arch/x86/stage1_mtrr.c	2008-12-08 20:40:02 UTC (rev 1066)
+++ coreboot-v3/arch/x86/stage1_mtrr.c	2008-12-10 18:34:16 UTC (rev 1067)
@@ -67,6 +67,11 @@
+/* early_mtrr_init was only usable for ROMCC compiled code. It nukes CAR.
+ * The only remaining purpose would be to enable ROM caching here instead of
+ * in stage0.S and even that is debatable.
+ */
+#if 0
 /* the fixed and variable MTTRs are power-up with random values,
  * clear them to MTRR_TYPE_UNCACHEABLE for safty.
@@ -130,6 +135,7 @@
 int early_mtrr_init_detected(void)

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