[RFC PATCH v2 11/20] powerpc/mm: Complement huge_pte_alloc() for all non HUGEPD setups

[Christophe Leroy]

huge_pte_alloc() for non-HUGEPD targets is reserved for 8xx at the
moment. In order to convert other targets for non-HUGEPD, complement
huge_pte_alloc() to support any standard cont-PxD setup.

Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
 arch/powerpc/mm/hugetlbpage.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 42b12e1ec851..f8aefa1e7363 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -195,11 +195,34 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, struct 
vm_area_struct *vma,
 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
                      unsigned long addr, unsigned long sz)
 {
-       pmd_t *pmd = pmd_off(mm, addr);
+       pgd_t *pgd;
+       p4d_t *p4d;
+       pud_t *pud;
+       pmd_t *pmd;
+
+       addr &= ~(sz - 1);
+       pgd = pgd_offset(mm, addr);
+
+       p4d = p4d_offset(pgd, addr);
+       if (sz >= PGDIR_SIZE)
+               return (pte_t *)p4d;
+
+       pud = pud_alloc(mm, p4d, addr);
+       if (!pud)
+               return NULL;
+       if (sz >= PUD_SIZE)
+               return (pte_t *)pud;
+
+       pmd = pmd_alloc(mm, pud, addr);
+       if (!pmd)
+               return NULL;
 
        if (sz < PMD_SIZE)
                return pte_alloc_huge(mm, pmd, addr, sz);
 
+       if (!IS_ENABLED(CONFIG_PPC_8xx))
+               return (pte_t *)pmd;
+
        if (sz != SZ_8M)
                return NULL;
        if (!pte_alloc_huge(mm, pmd, addr, sz))
-- 
2.44.0