linux-kernel - [PATCH 3.10 20/51] ARM: LPAE: use signed arithmetic for mask definitions

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Message-Id: <20150203231725.202535867@linuxfoundation.org>
Date:	Tue,  3 Feb 2015 15:17:02 -0800
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Cyril Chemparathy <cyril@...com>,
	Vitaly Andrianov <vitalya@...com>,
	Nicolas Pitre <nico@...aro.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Santosh Shilimkar <santosh.shilimkar@...com>,
	Subash Patel <subash.rp@...sung.com>,
	Will Deacon <will.deacon@....com>,
	Hou Pengyang <houpengyang@...wei.com>
Subject: [PATCH 3.10 20/51] ARM: LPAE: use signed arithmetic for mask definitions

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Cyril Chemparathy <cyril@...com>

commit 926edcc747e2efb3c9add7ed4dbc4e7a3a959d02 upstream.

This patch applies to PAGE_MASK, PMD_MASK, and PGDIR_MASK, where forcing
unsigned long math truncates the mask at the 32-bits.  This clearly does bad
things on PAE systems.

This patch fixes this problem by defining these masks as signed quantities.
We then rely on sign extension to do the right thing.

Signed-off-by: Cyril Chemparathy <cyril@...com>
Signed-off-by: Vitaly Andrianov <vitalya@...com>
Reviewed-by: Nicolas Pitre <nico@...aro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@....com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@...com>
Tested-by: Subash Patel <subash.rp@...sung.com>
Signed-off-by: Will Deacon <will.deacon@....com>
Cc: Hou Pengyang <houpengyang@...wei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arm/include/asm/page.h           |    2 +-
 arch/arm/include/asm/pgtable-3level.h |    6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

--- a/arch/arm/include/asm/page.h
+++ b/arch/arm/include/asm/page.h
@@ -13,7 +13,7 @@
 /* PAGE_SHIFT determines the page size */
 #define PAGE_SHIFT		12
 #define PAGE_SIZE		(_AC(1,UL) << PAGE_SHIFT)
-#define PAGE_MASK		(~(PAGE_SIZE-1))
+#define PAGE_MASK		(~((1 << PAGE_SHIFT) - 1))
 
 #ifndef __ASSEMBLY__
 
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -48,16 +48,16 @@
 #define PMD_SHIFT		21
 
 #define PMD_SIZE		(1UL << PMD_SHIFT)
-#define PMD_MASK		(~(PMD_SIZE-1))
+#define PMD_MASK		(~((1 << PMD_SHIFT) - 1))
 #define PGDIR_SIZE		(1UL << PGDIR_SHIFT)
-#define PGDIR_MASK		(~(PGDIR_SIZE-1))
+#define PGDIR_MASK		(~((1 << PGDIR_SHIFT) - 1))
 
 /*
  * section address mask and size definitions.
  */
 #define SECTION_SHIFT		21
 #define SECTION_SIZE		(1UL << SECTION_SHIFT)
-#define SECTION_MASK		(~(SECTION_SIZE-1))
+#define SECTION_MASK		(~((1 << SECTION_SHIFT) - 1))
 
 #define USER_PTRS_PER_PGD	(PAGE_OFFSET / PGDIR_SIZE)
 


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