[PATCH 06/16] xen: disable PAT

From: Jeremy Fitzhardinge
Date: Thu May 07 2009 - 20:18:33 EST


From: Ian Campbell <ian.campbell@xxxxxxxxxx>

Impact: disable PAT under Xen

Xen imposes a particular PAT layout on all paravirtual guests which
does not match the layout Linux would like to use.

Force PAT to be disabled until this is resolved.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
arch/x86/include/asm/pat.h | 5 +++++
arch/x86/mm/pat.c | 5 -----
arch/x86/xen/enlighten.c | 3 +++
3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/pat.h b/arch/x86/include/asm/pat.h
index 2cd07b9..d434a4e 100644
--- a/arch/x86/include/asm/pat.h
+++ b/arch/x86/include/asm/pat.h
@@ -6,8 +6,13 @@

#ifdef CONFIG_X86_PAT
extern int pat_enabled;
+extern void pat_disable(const char *reason);
#else
static const int pat_enabled;
+static inline void pat_disable(const char *reason)
+{
+ (void)reason;
+}
#endif

extern void pat_init(void);
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 640339e..4d2a4df 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -43,11 +43,6 @@ static int __init nopat(char *str)
return 0;
}
early_param("nopat", nopat);
-#else
-static inline void pat_disable(const char *reason)
-{
- (void)reason;
-}
#endif


diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index f917381..48c91dc 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -49,6 +49,7 @@
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/reboot.h>
+#include <asm/pat.h>

#include "xen-ops.h"
#include "mmu.h"
@@ -1034,6 +1035,8 @@ asmlinkage void __init xen_start_kernel(void)
add_preferred_console("hvc", 0, NULL);
}

+ pat_disable("PAT disabled on Xen");
+
xen_raw_console_write("about to get started...\n");

/* Start the world */
--
1.6.0.6

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