[PATCH v9 04/32] powerpc: mm: add PMD swap-exclusive helpers

[PATCH v9 04/32] powerpc: mm: add PMD swap-exclusive helpers

[Usama Arif]

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.

book3s64 builds a swap PMD by running the PTE encoding over pmd_pte(), so
the PMD helpers wrap the PTE ones and reuse _PAGE_SWP_EXCLUSIVE, exactly
as the soft-dirty PMD helpers next to them do. It is also the only powerpc
variant that selects ARCH_HAS_PMD_SOFTLEAVES, via PPC_THP.

Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Usama Arif <usama.arif@linux.dev>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index dff8790a047db..458c85cebfa65 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1060,6 +1060,12 @@ static inline pte_t *pmdp_ptep(pmd_t *pmd)
 #endif
 #endif /* CONFIG_HAVE_ARCH_SOFT_DIRTY */
 
+#ifdef CONFIG_ARCH_HAS_PMD_SOFTLEAVES
+#define pmd_swp_mkexclusive(pmd)	pte_pmd(pte_swp_mkexclusive(pmd_pte(pmd)))
+#define pmd_swp_exclusive(pmd)		pte_swp_exclusive(pmd_pte(pmd))
+#define pmd_swp_clear_exclusive(pmd)	pte_pmd(pte_swp_clear_exclusive(pmd_pte(pmd)))
+#endif
+
 #ifdef CONFIG_ARCH_HAS_PTE_PROTNONE
 static inline int pmd_protnone(pmd_t pmd)
 {
-- 
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