[patch 14/16] x86_64: Add a guard page at the end of the 47bit address space

Chris Wright
2005-05-23T23:50:02Z

[PATCH] x86_64: Add a guard page at the end of the 47bit address space

This works around a bug in the AMD K8 CPUs.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Chris Wright <chrisw@osdl.org>
---

processor.h | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

Index: release-2.6.11/include/asm-x86_64/processor.h
===================================================================
--- release-2.6.11.orig/include/asm-x86_64/processor.h
+++ release-2.6.11/include/asm-x86_64/processor.h
@@ -160,9 +160,9 @@ static inline void clear_in_cr4 (unsigne

/*
- * User space process size. 47bits.
+ * User space process size. 47bits minus one guard page.
*/
-#define TASK_SIZE (0x800000000000UL)
+#define TASK_SIZE (0x800000000000UL - 4096)

/* This decides where the kernel will search for a free chunk of vm
* space during mmap's.