Subject: [RFC PATCH 06/21] powerpc/book3s/hash64/devmap: Use H_PAGE_THP_HUGE when setting up level huge devmap pte entries

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Thu, 27 Feb 2020 12:26:05 +0530

H_PAGE_THP_HUGE is used to differentiate between a THP hugepage and hugetlb
hugepage entries. The difference is w.r.t how we handle hash fault on these
address. THP address enables MPSS in segments. We want to manage devmap hugepage
entries similar to THP pt entries. Hence use H_PAGE_THP_HUGE for devmap huge pte
entries.

With current code while handling hash pte fault, we do set is_thp = true when
finding devmap pte huge pte entries. Hence this patch is not fixing any bugs.

Signed-off-by: Aneesh Kumar K.V <[email-masked]>
---
 arch/powerpc/include/asm/book3s/64/hash-4k.h  | 6 ++++++
 arch/powerpc/include/asm/book3s/64/hash-64k.h | 8 +++++++-
 arch/powerpc/include/asm/book3s/64/pgtable.h  | 4 +++-
 arch/powerpc/include/asm/book3s/64/radix.h    | 5 +++++
 4 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h
index 8fd8599c9395..3f9ae3585ab9 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-4k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h
@@ -156,6 +156,12 @@ extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm,
 extern int hash__has_transparent_hugepage(void);
 #endif
 
+static inline pmd_t hash__pmd_mkdevmap(pmd_t pmd)
+{
+	BUG();
+	return pmd;
+}
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* _ASM_POWERPC_BOOK3S_64_HASH_4K_H */
diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index d1d9177d9ebd..0729c034e56f 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -246,7 +246,7 @@ static inline void mark_hpte_slot_valid(unsigned char *hpte_slot_array,
  */
 static inline int hash__pmd_trans_huge(pmd_t pmd)
 {
-	return !!((pmd_val(pmd) & (_PAGE_PTE | H_PAGE_THP_HUGE)) ==
+	return !!((pmd_val(pmd) & (_PAGE_PTE | H_PAGE_THP_HUGE | _PAGE_DEVMAP)) ==
 		  (_PAGE_PTE | H_PAGE_THP_HUGE));
 }
 
@@ -272,6 +272,12 @@ extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm,
 				       unsigned long addr, pmd_t *pmdp);
 extern int hash__has_transparent_hugepage(void);
 #endif /*  CONFIG_TRANSPARENT_HUGEPAGE */
+
+static inline pmd_t hash__pmd_mkdevmap(pmd_t pmd)
+{
+	return __pmd(pmd_val(pmd) | (_PAGE_PTE | H_PAGE_THP_HUGE | _PAGE_DEVMAP));
+}
+
 #endif	/* __ASSEMBLY__ */
 
 #endif /* _ASM_POWERPC_BOOK3S_64_HASH_64K_H */
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 89eb7b350df8..03521a8b0292 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1308,7 +1308,9 @@ extern void serialize_against_pte_lookup(struct mm_struct *mm);
 
 static inline pmd_t pmd_mkdevmap(pmd_t pmd)
 {
-	return __pmd(pmd_val(pmd) | (_PAGE_PTE | _PAGE_DEVMAP));
+	if (radix_enabled())
+		return radix__pmd_mkdevmap(pmd);
+	return hash__pmd_mkdevmap(pmd);
 }
 
 static inline int pmd_devmap(pmd_t pmd)
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index d97db3ad9aae..a1c60d5b50af 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -263,6 +263,11 @@ static inline int radix__has_transparent_hugepage(void)
 }
 #endif
 
+static inline pmd_t radix__pmd_mkdevmap(pmd_t pmd)
+{
+	return __pmd(pmd_val(pmd) | (_PAGE_PTE | _PAGE_DEVMAP));
+}
+
 extern int __meminit radix__vmemmap_create_mapping(unsigned long start,
 					     unsigned long page_size,
 					     unsigned long phys);
-- 
2.24.1