From 224fa094f4ea670fefe0dde465fab6cbf38be3be Mon Sep 17 00:00:00 2001
From: Steven Capper <steve.capper@linaro.org>
Date: Fri, 18 Jul 2014 16:15:27 +0100
Subject: ARM: 8108/1: mm: Introduce {pte,pmd}_isset and {pte,pmd}_isclear

Long descriptors on ARM are 64 bits, and some pte functions such as
pte_dirty return a bitwise-and of a flag with the pte value. If the
flag to be tested resides in the upper 32 bits of the pte, then we run
into the danger of the result being dropped if downcast.

For example:
	gather_stats(page, md, pte_dirty(*pte), 1);
where pte_dirty(*pte) is downcast to an int.

This patch introduces a new macro pte_isset which performs the bitwise
and, then performs a double logical invert (where needed) to ensure
predictable downcasting. The logical inverse pte_isclear is also
introduced.

Equivalent pmd functions for Transparent HugePages have also been
added.

Signed-off-by: Steve Capper <steve.capper@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
(cherry picked from commit f2950706871c4b6e8c0f0d7c3f62d35930b8de63)
Change-Id: I2d17ab87a364a3e839c71fab3f4507e722288daf
Reviewed-on: http://git.am.freescale.net:8181/23332
Reviewed-by: Matthew Weigel <Matthew.Weigel@freescale.com>
Tested-by: Review Code-CDREVIEW <CDREVIEW@freescale.com>

diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 5bee994..f98cbda 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -206,14 +206,18 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
 #define pte_huge(pte)		(pte_val(pte) && !(pte_val(pte) & PTE_TABLE_BIT))
 #define pte_mkhuge(pte)		(__pte(pte_val(pte) & ~PTE_TABLE_BIT))
 
-#define pmd_young(pmd)		(pmd_val(pmd) & PMD_SECT_AF)
+#define pmd_isset(pmd, val)	((u32)(val) == (val) ? pmd_val(pmd) & (val) \
+						: !!(pmd_val(pmd) & (val)))
+#define pmd_isclear(pmd, val)	(!(pmd_val(pmd) & (val)))
+
+#define pmd_young(pmd)		(pmd_isset((pmd), PMD_SECT_AF))
 
 #define __HAVE_ARCH_PMD_WRITE
-#define pmd_write(pmd)		(!(pmd_val(pmd) & PMD_SECT_RDONLY))
+#define pmd_write(pmd)		(pmd_isclear((pmd), PMD_SECT_RDONLY))
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-#define pmd_trans_huge(pmd)	(pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT))
-#define pmd_trans_splitting(pmd) (pmd_val(pmd) & PMD_SECT_SPLITTING)
+#define pmd_trans_huge(pmd)	(pmd_val(pmd) && !pmd_table(pmd))
+#define pmd_trans_splitting(pmd) (pmd_isset((pmd), PMD_SECT_SPLITTING))
 #endif
 
 #define PMD_BIT_FUNC(fn,op) \
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 4078c6d..20e7cca 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -214,18 +214,22 @@ static inline pte_t *pmd_page_vaddr(pmd_t pmd)
 
 #define pte_clear(mm,addr,ptep)	set_pte_ext(ptep, __pte(0), 0)
 
+#define pte_isset(pte, val)	((u32)(val) == (val) ? pte_val(pte) & (val) \
+						: !!(pte_val(pte) & (val)))
+#define pte_isclear(pte, val)	(!(pte_val(pte) & (val)))
+
 #define pte_none(pte)		(!pte_val(pte))
-#define pte_present(pte)	(pte_val(pte) & L_PTE_PRESENT)
-#define pte_valid(pte)		(pte_val(pte) & L_PTE_VALID)
+#define pte_present(pte)	(pte_isset((pte), L_PTE_PRESENT))
+#define pte_valid(pte)		(pte_isset((pte), L_PTE_VALID))
 #define pte_accessible(mm, pte)	(mm_tlb_flush_pending(mm) ? pte_present(pte) : pte_valid(pte))
-#define pte_write(pte)		(!(pte_val(pte) & L_PTE_RDONLY))
-#define pte_dirty(pte)		(pte_val(pte) & L_PTE_DIRTY)
-#define pte_young(pte)		(pte_val(pte) & L_PTE_YOUNG)
-#define pte_exec(pte)		(!(pte_val(pte) & L_PTE_XN))
+#define pte_write(pte)		(pte_isclear((pte), L_PTE_RDONLY))
+#define pte_dirty(pte)		(pte_isset((pte), L_PTE_DIRTY))
+#define pte_young(pte)		(pte_isset((pte), L_PTE_YOUNG))
+#define pte_exec(pte)		(pte_isclear((pte), L_PTE_XN))
 #define pte_special(pte)	(0)
 
 #define pte_valid_user(pte)	\
-	(pte_valid(pte) && (pte_val(pte) & L_PTE_USER) && pte_young(pte))
+	(pte_valid(pte) && pte_isset((pte), L_PTE_USER) && pte_young(pte))
 
 #if __LINUX_ARM_ARCH__ < 6
 static inline void __sync_icache_dcache(pte_t pteval)
-- 
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