[PATCH v7 02/29] arm64: mm: add PMD swap-exclusive helpers

[Usama Arif]

A later patch keeps a PMD-mapped anonymous THP mapped by a PMD across the
swap round-trip, so PG_anon_exclusive now has to survive in a swap PMD and
not just in a swap PTE.

arm64 encodes a swap PMD exactly like a swap PTE, so the new helpers wrap
the PTE ones and reuse PTE_SWP_EXCLUSIVE.

Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Usama Arif <usama.arif@xxxxxxxxx>
---
 arch/arm64/include/asm/pgtable.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index e89ec5f4787b4..d3f53a601aed3 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -599,6 +599,12 @@ static inline int pmd_protnone(pmd_t pmd)
 #define pmd_swp_clear_uffd(pmd) \
 				pte_pmd(pte_swp_clear_uffd(pmd_pte(pmd)))
 #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */
+#ifdef CONFIG_ARCH_HAS_PMD_SOFTLEAVES
+#define pmd_swp_exclusive(pmd)	pte_swp_exclusive(pmd_pte(pmd))
+#define pmd_swp_mkexclusive(pmd)	pte_pmd(pte_swp_mkexclusive(pmd_pte(pmd)))
+#define pmd_swp_clear_exclusive(pmd) \
+				pte_pmd(pte_swp_clear_exclusive(pmd_pte(pmd)))
+#endif
 
 #define pmd_write(pmd)		pte_write(pmd_pte(pmd))
 
-- 
2.53.0-Meta