[PATCHv3 04/11] arm64: Provide pmdp_establish() helper

From	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Newsgroups	linux.kernel
Subject	[PATCHv3 04/11] arm64: Provide pmdp_establish() helper
Date	2017-09-12 17:50 +0200
Message-ID	<uoVBN-37Z-49@gated-at.bofh.it> (permalink)
References	<uoVBL-37Z-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: Catalin Marinas <catalin.marinas@arm.com>

We need an atomic way to setup pmd page table entry, avoiding races with
CPU setting dirty/accessed bits. This is required to implement
pmdp_invalidate() that doesn't lose these bits.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/arm64/include/asm/pgtable.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index bc4e92337d16..09bb86533d32 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -663,6 +663,13 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 {
 	ptep_set_wrprotect(mm, address, (pte_t *)pmdp);
 }
+
+#define pmdp_establish pmdp_establish
+static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
+		unsigned long address, pmd_t *pmdp, pmd_t pmd)
+{
+	return __pmd(xchg_relaxed(&pmd_val(*pmdp), pmd_val(pmd)));
+}
 #endif
 
 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
-- 
2.14.1

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[PATCHv3 04/11] arm64: Provide pmdp_establish() helper "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-09-12 17:50 +0200

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