[PATCH v9 05/32] riscv: mm: add PMD swap-exclusive helpers

[Usama Arif <usama.arif@linux.dev>]

Prepare for keeping a PMD-mapped anonymous THP mapped by a PMD across the
swap round-trip, which makes PG_anon_exclusive have 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@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org
Signed-off-by: Usama Arif <usama.arif@linux.dev>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
---
 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 2ebd5fa5adc58..fda94dba9bb3e 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