[PATCH RFC 18/24] userfaultfd: wp: add pmd_swp_*uffd_wp() helpers

[Peter Xu]

Adding these missing helpers for uffd-wp operations with pmd
swap/migration entries.

Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
 arch/x86/include/asm/pgtable.h     | 15 +++++++++++++++
 include/asm-generic/pgtable_uffd.h | 15 +++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 7a71158982f4..aa2eb36d7edf 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1401,6 +1401,21 @@ static inline pte_t pte_swp_clear_uffd_wp(pte_t pte)
 {
 	return pte_clear_flags(pte, _PAGE_SWP_UFFD_WP);
 }
+
+static inline pmd_t pmd_swp_mkuffd_wp(pmd_t pmd)
+{
+	return pmd_set_flags(pmd, _PAGE_SWP_UFFD_WP);
+}
+
+static inline int pmd_swp_uffd_wp(pmd_t pmd)
+{
+	return pmd_flags(pmd) & _PAGE_SWP_UFFD_WP;
+}
+
+static inline pmd_t pmd_swp_clear_uffd_wp(pmd_t pmd)
+{
+	return pmd_clear_flags(pmd, _PAGE_SWP_UFFD_WP);
+}
 #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */
 
 #define PKRU_AD_BIT 0x1
diff --git a/include/asm-generic/pgtable_uffd.h b/include/asm-generic/pgtable_uffd.h
index 643d1bf559c2..828966d4c281 100644
--- a/include/asm-generic/pgtable_uffd.h
+++ b/include/asm-generic/pgtable_uffd.h
@@ -46,6 +46,21 @@ static __always_inline pte_t pte_swp_clear_uffd_wp(pte_t pte)
 {
 	return pte;
 }
+
+static inline pmd_t pmd_swp_mkuffd_wp(pmd_t pmd)
+{
+	return pmd;
+}
+
+static inline int pmd_swp_uffd_wp(pmd_t pmd)
+{
+	return 0;
+}
+
+static inline pmd_t pmd_swp_clear_uffd_wp(pmd_t pmd)
+{
+	return pmd;
+}
 #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */
 
 #endif /* _ASM_GENERIC_PGTABLE_UFFD_H */
-- 
2.17.1