[PATCH] i386: Enable support for fixed-range IORRs to keep RdMem & WrMem in sync

If our copy of the MTRRs of the BSP has RdMem or WrMem set, and
we are running on an AMD64/K8 system, the boot CPU must have had
MtrrFixDramEn and MtrrFixDramModEn set (otherwise our RDMSR would
have copied these bits cleared), so we set them on this CPU as well.

This allows us to keep the AMD64/K8 RdMem and WrMem bits in sync
across the CPUs of SMP systems in order to fullfill the duty of
system software to "initialize and maintain MTRR consistency
across all processors." as written in the AMD and Intel manuals.

If an WRMSR instruction fails because MtrrFixDramModEn is not
set, I expect that also the Intel-style MTRR bits are not updated.

AK: minor cleanup, moved MSR defines around

Signed-off-by: Bernhard Kaindl <bk@suse.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Dave Jones <davej@codemonkey.org.uk>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/asm-i386/msr-index.h b/include/asm-i386/msr-index.h
index f1190802283d..a02eb2991349 100644
--- a/include/asm-i386/msr-index.h
+++ b/include/asm-i386/msr-index.h
@@ -87,6 +87,11 @@
 #define MSR_K7_CLK_CTL                  0xc001001b
 #define MSR_K8_TOP_MEM2                 0xc001001d
 #define MSR_K8_SYSCFG                   0xc0010010
+
+#define K8_MTRRFIXRANGE_DRAM_ENABLE     0x00040000 /* MtrrFixDramEn bit    */
+#define K8_MTRRFIXRANGE_DRAM_MODIFY     0x00080000 /* MtrrFixDramModEn bit */
+#define K8_MTRR_RDMEM_WRMEM_MASK        0x18181818 /* Mask: RdMem|WrMem    */
+
 #define MSR_K7_HWCR                     0xc0010015
 #define MSR_K8_HWCR                     0xc0010015
 #define MSR_K7_FID_VID_CTL              0xc0010041