linux-kernel - [PATCH] [11/36] Don't drop NX bit in pte modifier functions for 32bit

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Message-Id: <20080116221510.1485B150C8@wotan.suse.de>
Date:	Wed, 16 Jan 2008 23:15:10 +0100 (CET)
From:	Andi Kleen <ak@...e.de>
To:	linux-kernel@...r.kernel.org, mingo@...e.hu, tglx@...utronix.de,
	jbeulich@...ell.com, venkatesh.pallipadi@...el.com
Subject: [PATCH] [11/36] Don't drop NX bit in pte modifier functions for 32bit


The pte_* modifier functions that cleared bits dropped the NX bit on 32bit
PAE because they only worked in int, but NX is in bit 63. Fix that
by adding appropiate casts so that the arithmetic happens as long long
on PAE kernels.

I decided to just use 64bit arithmetic instead of open coding like
pte_modify() because gcc should generate good enough code for that now.

While this looks in theory like a .24 candidate this might trigger
some subtle latent bugs so it's better to delay it for .25 for more
testing.

Signed-off-by: Andi Kleen <ak@...e.de>
Acked-by: Jan Beulich <jbeulich@...ell.com>

---
 include/asm-x86/pgtable.h |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Index: linux/include/asm-x86/pgtable.h
===================================================================
--- linux.orig/include/asm-x86/pgtable.h
+++ linux/include/asm-x86/pgtable.h
@@ -151,17 +151,17 @@ static inline int pmd_large(pmd_t pte) {
 		(_PAGE_PSE|_PAGE_PRESENT);
 }
 
-static inline pte_t pte_mkclean(pte_t pte)	{ return __pte(pte_val(pte) & ~_PAGE_DIRTY); }
-static inline pte_t pte_mkold(pte_t pte)	{ return __pte(pte_val(pte) & ~_PAGE_ACCESSED); }
-static inline pte_t pte_wrprotect(pte_t pte)	{ return __pte(pte_val(pte) & ~_PAGE_RW); }
-static inline pte_t pte_mkexec(pte_t pte)	{ return __pte(pte_val(pte) & ~_PAGE_NX); }
+static inline pte_t pte_mkclean(pte_t pte)	{ return __pte(pte_val(pte) & ~(pteval_t)_PAGE_DIRTY); }
+static inline pte_t pte_mkold(pte_t pte)	{ return __pte(pte_val(pte) & ~(pteval_t)_PAGE_ACCESSED); }
+static inline pte_t pte_wrprotect(pte_t pte)	{ return __pte(pte_val(pte) & ~(pteval_t)_PAGE_RW); }
+static inline pte_t pte_mkexec(pte_t pte)	{ return __pte(pte_val(pte) & ~(pteval_t)_PAGE_NX); }
 static inline pte_t pte_mkdirty(pte_t pte)	{ return __pte(pte_val(pte) | _PAGE_DIRTY); }
 static inline pte_t pte_mkyoung(pte_t pte)	{ return __pte(pte_val(pte) | _PAGE_ACCESSED); }
 static inline pte_t pte_mkwrite(pte_t pte)	{ return __pte(pte_val(pte) | _PAGE_RW); }
 static inline pte_t pte_mkhuge(pte_t pte)	{ return __pte(pte_val(pte) | _PAGE_PSE); }
-static inline pte_t pte_clrhuge(pte_t pte)	{ return __pte(pte_val(pte) & ~_PAGE_PSE); }
+static inline pte_t pte_clrhuge(pte_t pte)	{ return __pte(pte_val(pte) & ~(pteval_t)_PAGE_PSE); }
 static inline pte_t pte_mkglobal(pte_t pte)	{ return __pte(pte_val(pte) | _PAGE_GLOBAL); }
-static inline pte_t pte_clrglobal(pte_t pte)	{ return __pte(pte_val(pte) & ~_PAGE_GLOBAL); }
+static inline pte_t pte_clrglobal(pte_t pte)	{ return __pte(pte_val(pte) & ~(pteval_t)_PAGE_GLOBAL); }
 
 extern pteval_t __supported_pte_mask;
 
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