[PATCH] arm64/mm: Change THP helpers to comply with generic MM semantics

[Anshuman Khandual]

Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
 arch/arm64/include/asm/pgtable.h | 74 ++++++++++++++++++++++++++++----
 arch/arm64/mm/hugetlbpage.c      |  2 +-
 2 files changed, 67 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 44883038dbe6..86c22a4fa427 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -348,15 +348,72 @@ static inline int pmd_protnone(pmd_t pmd)
 }
 #endif
 
+#define pmd_table(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
+				 PMD_TYPE_TABLE)
+#define pmd_sect(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
+				 PMD_TYPE_SECT)
+static pmd_t pmd_mksplitting(pmd_t pmd)
+{
+	unsigned long mask = PMD_TYPE_MASK;
+	unsigned long val = pmd_val(pmd);
+
+	val = (val & ~mask) | PMD_TABLE_BIT;
+
+	return __pmd(val);
+}
+
+static bool pmd_splitting(pmd_t pmd)
+{
+	unsigned long mask = PMD_TYPE_MASK;
+	unsigned long val = pmd_val(pmd);
+
+	if ((val & mask) == PMD_TABLE_BIT)
+		return true;
+
+	return false;
+}
+
+static bool pmd_mapped(pmd_t pmd)
+{
+	return pmd_sect(pmd);
+}
+
+static inline int pmd_present(pmd_t pmd)
+{
+	pte_t pte = pmd_pte(pmd);
+
+	if (pte_present(pte))
+		return 1;
+
+	if (pmd_splitting(pmd))
+		return 1;
+
+	return 0;
+}
+
 /*
  * THP definitions.
  */
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-#define pmd_trans_huge(pmd)	(pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT))
+static inline int pmd_trans_huge(pmd_t pmd)
+{
+	if (!pmd_present(pmd))
+		return 0;
+
+	if (!pmd_val(pmd))
+		return 0;
+
+	if (pmd_mapped(pmd))
+		return 1;
+
+	if (pmd_splitting(pmd))
+		return 1;
+
+	return 0;
+}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
-#define pmd_present(pmd)	pte_present(pmd_pte(pmd))
 #define pmd_dirty(pmd)		pte_dirty(pmd_pte(pmd))
 #define pmd_young(pmd)		pte_young(pmd_pte(pmd))
 #define pmd_valid(pmd)		pte_valid(pmd_pte(pmd))
@@ -366,7 +423,12 @@ static inline int pmd_protnone(pmd_t pmd)
 #define pmd_mkclean(pmd)	pte_pmd(pte_mkclean(pmd_pte(pmd)))
 #define pmd_mkdirty(pmd)	pte_pmd(pte_mkdirty(pmd_pte(pmd)))
 #define pmd_mkyoung(pmd)	pte_pmd(pte_mkyoung(pmd_pte(pmd)))
-#define pmd_mknotvalid(pmd)	(__pmd(pmd_val(pmd) & ~PMD_SECT_VALID))
+
+static inline pmd_t pmd_mknotvalid(pmd_t pmd)
+{
+	BUG_ON(pmd_table(pmd));
+	return pmd_mksplitting(pmd);
+}
 
 #define pmd_thp_or_huge(pmd)	(pmd_huge(pmd) || pmd_trans_huge(pmd))
 
@@ -437,10 +499,6 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 
 #define pmd_bad(pmd)		(!(pmd_val(pmd) & PMD_TABLE_BIT))
 
-#define pmd_table(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
-				 PMD_TYPE_TABLE)
-#define pmd_sect(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
-				 PMD_TYPE_SECT)
 #define pmd_leaf(pmd)		pmd_sect(pmd)
 
 #if defined(CONFIG_ARM64_64K_PAGES) || CONFIG_PGTABLE_LEVELS < 3
@@ -834,7 +892,7 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
 
 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
 #define __pmd_to_swp_entry(pmd)        ((swp_entry_t) { pmd_val(pmd) })
-#define __swp_entry_to_pmd(swp)        __pmd((swp).val)
+#define __swp_entry_to_pmd(swp)        __pmd((swp).val & ~PMD_TABLE_BIT)
 #endif
 
 /*
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index bbeb6a5a6ba6..056fe716b9f8 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -283,7 +283,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
 	if (!(sz == PMD_SIZE || sz == CONT_PMD_SIZE) &&
 	    pmd_none(pmd))
 		return NULL;
-	if (pmd_huge(pmd) || !pmd_present(pmd))
+	if (pmd_huge(pmd) || !pte_present(pmd_pte(pmd)))
 		return (pte_t *)pmdp;
 
 	if (sz == CONT_PTE_SIZE)
-- 
2.20.1