[PATCH 48 of 66] add pmd_modify

[Andrea Arcangeli]

From: Johannes Weiner <hannes@xxxxxxxxxxx>

Add pmd_modify() for use with mprotect() on huge pmds.

Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
---

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -325,6 +325,16 @@ static inline pte_t pte_modify(pte_t pte
 	return __pte(val);
 }
 
+static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
+{
+	pmdval_t val = pmd_val(pmd);
+
+	val &= _HPAGE_CHG_MASK;
+	val |= massage_pgprot(newprot) & ~_HPAGE_CHG_MASK;
+
+	return __pmd(val);
+}
+
 /* mprotect needs to preserve PAT bits when updating vm_page_prot */
 #define pgprot_modify pgprot_modify
 static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -72,6 +72,7 @@
 /* Set of bits not changed in pte_modify */
 #define _PAGE_CHG_MASK	(PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT |		\
 			 _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY)
+#define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE)
 
 #define _PAGE_CACHE_MASK	(_PAGE_PCD | _PAGE_PWT)
 #define _PAGE_CACHE_WB		(0)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/