linux-kernel - [PATCH 1 of 8] x86: define PTE_MASK in a universally useful way

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Date:	Fri, 09 May 2008 12:02:39 +0100
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Hugh Dickins <hugh@...itas.com>
Subject: [PATCH 1 of 8] x86: define PTE_MASK in a universally useful way

Define PTE_MASK so that it contains a meaningful value for all x86
pagetable configurations.  Previously it was defined as a "long" which
means that it was too short to cover a 32-bit PAE pte entry.

It is now defined as a pteval_t, which is an integer type long enough
to contain a full pte (or pmd, pud, pgd).

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
---
 include/asm-x86/page.h |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/include/asm-x86/page.h b/include/asm-x86/page.h
--- a/include/asm-x86/page.h
+++ b/include/asm-x86/page.h
@@ -10,8 +10,13 @@
 
 #ifdef __KERNEL__
 
-#define PHYSICAL_PAGE_MASK	(PAGE_MASK & __PHYSICAL_MASK)
-#define PTE_MASK		(_AT(long, PHYSICAL_PAGE_MASK))
+/* Cast PAGE_MASK to a signed type so that it is sign-extended if
+   virtual addresses are 32-bits but physical addresses are larger
+   (ie, 32-bit PAE). */
+#define PHYSICAL_PAGE_MASK	(((signed long)PAGE_MASK) & __PHYSICAL_MASK)
+
+/* PTE_MASK extracts the PFN from a (pte|pmd|pud|pgd)val_t */
+#define PTE_MASK		((pteval_t)PHYSICAL_PAGE_MASK)
 
 #define PMD_PAGE_SIZE		(_AC(1, UL) << PMD_SHIFT)
 #define PMD_PAGE_MASK		(~(PMD_PAGE_SIZE-1))
@@ -24,8 +29,8 @@
 /* to align the pointer to the (next) page boundary */
 #define PAGE_ALIGN(addr)	(((addr)+PAGE_SIZE-1)&PAGE_MASK)
 
-#define __PHYSICAL_MASK		_AT(phys_addr_t, (_AC(1,ULL) << __PHYSICAL_MASK_SHIFT) - 1)
-#define __VIRTUAL_MASK		((_AC(1,UL) << __VIRTUAL_MASK_SHIFT) - 1)
+#define __PHYSICAL_MASK		((((phys_addr_t)1) << __PHYSICAL_MASK_SHIFT) - 1)
+#define __VIRTUAL_MASK		((1UL << __VIRTUAL_MASK_SHIFT) - 1)
 
 #ifndef __ASSEMBLY__
 #include <linux/types.h>


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