powerpc/book3s64/mm: enable transparent pud hugepage

This is enabled only with radix translation and 1G hugepage size.  This
will be used with devdax device memory with a namespace alignment of 1G.

Anon transparent hugepage is not supported even though we do have helpers
checking pud_trans_huge().  We should never find that return true.  The
only expected pte bit combination is _PAGE_PTE | _PAGE_DEVMAP.

Some of the helpers are never expected to get called on hash translation
and hence is marked to call BUG() in such a case.

Link: https://lkml.kernel.org/r/20230724190759.483013-10-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 02e185d2e4d6..227fea53c217 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -967,6 +967,23 @@ unsigned long radix__pmd_hugepage_update(struct mm_struct *mm, unsigned long add
 	return old;
 }
 
+unsigned long radix__pud_hugepage_update(struct mm_struct *mm, unsigned long addr,
+					 pud_t *pudp, unsigned long clr,
+					 unsigned long set)
+{
+	unsigned long old;
+
+#ifdef CONFIG_DEBUG_VM
+	WARN_ON(!pud_devmap(*pudp));
+	assert_spin_locked(pud_lockptr(mm, pudp));
+#endif
+
+	old = radix__pte_update(mm, addr, pudp_ptep(pudp), clr, set, 1);
+	trace_hugepage_update_pud(addr, old, clr, set);
+
+	return old;
+}
+
 pmd_t radix__pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 			pmd_t *pmdp)
 
@@ -1043,6 +1060,17 @@ pmd_t radix__pmdp_huge_get_and_clear(struct mm_struct *mm,
 	return old_pmd;
 }
 
+pud_t radix__pudp_huge_get_and_clear(struct mm_struct *mm,
+				     unsigned long addr, pud_t *pudp)
+{
+	pud_t old_pud;
+	unsigned long old;
+
+	old = radix__pud_hugepage_update(mm, addr, pudp, ~0UL, 0);
+	old_pud = __pud(old);
+	return old_pud;
+}
+
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 void radix__ptep_set_access_flags(struct vm_area_struct *vma, pte_t *ptep,