[PATCH v7 05/29] riscv: 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.

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

Cc: Paul Walmsley <pjw@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Signed-off-by: Usama Arif <usama.arif@xxxxxxxxx>
---
 arch/riscv/include/asm/pgtable.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index d48f90140841e..b644db16bda94 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -1219,6 +1219,21 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
 }
 
 #ifdef CONFIG_ARCH_HAS_PMD_SOFTLEAVES
+static inline bool pmd_swp_exclusive(pmd_t pmd)
+{
+	return pte_swp_exclusive(pmd_pte(pmd));
+}
+
+static inline pmd_t pmd_swp_mkexclusive(pmd_t pmd)
+{
+	return pte_pmd(pte_swp_mkexclusive(pmd_pte(pmd)));
+}
+
+static inline pmd_t pmd_swp_clear_exclusive(pmd_t pmd)
+{
+	return pte_pmd(pte_swp_clear_exclusive(pmd_pte(pmd)));
+}
+
 #define __pmd_to_swp_entry(pmd) ((swp_entry_t) { pmd_val(pmd) })
 #define __swp_entry_to_pmd(swp) __pmd((swp).val)
 #endif /* CONFIG_ARCH_HAS_PMD_SOFTLEAVES */
-- 
2.53.0-Meta