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[PATCHv4,04/12] arm64: Provide pmdp_establish() helper

Message ID 20171213105756.69879-5-kirill.shutemov@linux.intel.com
State New
Headers show
Series None | expand

Commit Message

Kirill A. Shutemov Dec. 13, 2017, 10:57 a.m. UTC 
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(+)

-- 
2.15.0
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Patch

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 149d05fb9421..116d610a2620 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -676,6 +676,13 @@  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];