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Commit 2bd3a99c authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Linus Torvalds
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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).

This fixes an Xorg crash on 32-bit x86 with PAE due to corruption of the
NX bit in mprotect due to the incorrect type/value of PTE_MASK reported
by Hugh Dickins:

  "Yes, thanks Jeremy: I've checked that each stage builds and runs X on
   my boxes here, x86_32 and x86_32+PAE and x86_64.  (So even 1/8 is
   enough to fix the PAT pte_modify issue, though 2/8 then fixes
   compiler warnings.)"

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Tested-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8033c6e9

include/asm-x86/page.h

+9 −4
Original line number Diff line number Diff line
@@ -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>