Any updates on this?

On Mon, Dec 09, 2019 at 05:09:08PM +0200, Mike Rapoport wrote:
> From: Mike Rapoport <r...@linux.ibm.com>
> 
> Implement primitives necessary for the 4th level folding, add walks of p4d
> level where appropriate and replace 5level-fixup.h with pgtable-nop4d.h.
> 
> Signed-off-by: Mike Rapoport <r...@linux.ibm.com>
> ---
>  arch/powerpc/include/asm/book3s/32/pgtable.h  |  1 -
>  arch/powerpc/include/asm/book3s/64/hash.h     |  4 +-
>  arch/powerpc/include/asm/book3s/64/pgalloc.h  |  4 +-
>  arch/powerpc/include/asm/book3s/64/pgtable.h  | 58 ++++++++++--------
>  arch/powerpc/include/asm/book3s/64/radix.h    |  6 +-
>  arch/powerpc/include/asm/nohash/32/pgtable.h  |  1 -
>  arch/powerpc/include/asm/nohash/64/pgalloc.h  |  2 +-
>  .../include/asm/nohash/64/pgtable-4k.h        | 32 +++++-----
>  arch/powerpc/include/asm/nohash/64/pgtable.h  |  6 +-
>  arch/powerpc/include/asm/pgtable.h            |  8 +++
>  arch/powerpc/kvm/book3s_64_mmu_radix.c        | 59 ++++++++++++++++---
>  arch/powerpc/lib/code-patching.c              |  7 ++-
>  arch/powerpc/mm/book3s32/mmu.c                |  2 +-
>  arch/powerpc/mm/book3s32/tlb.c                |  4 +-
>  arch/powerpc/mm/book3s64/hash_pgtable.c       |  4 +-
>  arch/powerpc/mm/book3s64/radix_pgtable.c      | 19 ++++--
>  arch/powerpc/mm/book3s64/subpage_prot.c       |  6 +-
>  arch/powerpc/mm/hugetlbpage.c                 | 28 +++++----
>  arch/powerpc/mm/kasan/kasan_init_32.c         |  8 +--
>  arch/powerpc/mm/mem.c                         |  4 +-
>  arch/powerpc/mm/nohash/40x.c                  |  4 +-
>  arch/powerpc/mm/nohash/book3e_pgtable.c       | 15 +++--
>  arch/powerpc/mm/pgtable.c                     | 25 +++++++-
>  arch/powerpc/mm/pgtable_32.c                  | 28 +++++----
>  arch/powerpc/mm/pgtable_64.c                  | 10 ++--
>  arch/powerpc/mm/ptdump/hashpagetable.c        | 20 ++++++-
>  arch/powerpc/mm/ptdump/ptdump.c               | 22 ++++++-
>  arch/powerpc/xmon/xmon.c                      | 17 +++++-
>  28 files changed, 284 insertions(+), 120 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h 
> b/arch/powerpc/include/asm/book3s/32/pgtable.h
> index 0796533d37dd..e23de69bbaf8 100644
> --- a/arch/powerpc/include/asm/book3s/32/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
> @@ -2,7 +2,6 @@
>  #ifndef _ASM_POWERPC_BOOK3S_32_PGTABLE_H
>  #define _ASM_POWERPC_BOOK3S_32_PGTABLE_H
>  
> -#define __ARCH_USE_5LEVEL_HACK
>  #include <asm-generic/pgtable-nopmd.h>
>  
>  #include <asm/book3s/32/hash.h>
> diff --git a/arch/powerpc/include/asm/book3s/64/hash.h 
> b/arch/powerpc/include/asm/book3s/64/hash.h
> index 2781ebf6add4..876d1528c2cf 100644
> --- a/arch/powerpc/include/asm/book3s/64/hash.h
> +++ b/arch/powerpc/include/asm/book3s/64/hash.h
> @@ -134,9 +134,9 @@ static inline int get_region_id(unsigned long ea)
>  
>  #define      hash__pmd_bad(pmd)              (pmd_val(pmd) & H_PMD_BAD_BITS)
>  #define      hash__pud_bad(pud)              (pud_val(pud) & H_PUD_BAD_BITS)
> -static inline int hash__pgd_bad(pgd_t pgd)
> +static inline int hash__p4d_bad(p4d_t p4d)
>  {
> -     return (pgd_val(pgd) == 0);
> +     return (p4d_val(p4d) == 0);
>  }
>  #ifdef CONFIG_STRICT_KERNEL_RWX
>  extern void hash__mark_rodata_ro(void);
> diff --git a/arch/powerpc/include/asm/book3s/64/pgalloc.h 
> b/arch/powerpc/include/asm/book3s/64/pgalloc.h
> index f6968c811026..08603089ea5f 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgalloc.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgalloc.h
> @@ -87,9 +87,9 @@ static inline void pgd_free(struct mm_struct *mm, pgd_t 
> *pgd)
>       kmem_cache_free(PGT_CACHE(PGD_INDEX_SIZE), pgd);
>  }
>  
> -static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pud_t *pud)
> +static inline void p4d_populate(struct mm_struct *mm, p4d_t *pgd, pud_t *pud)
>  {
> -     *pgd =  __pgd(__pgtable_ptr_val(pud) | PGD_VAL_BITS);
> +     *pgd =  __p4d(__pgtable_ptr_val(pud) | PGD_VAL_BITS);
>  }
>  
>  static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h 
> b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index b01624e5c467..96fc48a42f4d 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -2,7 +2,7 @@
>  #ifndef _ASM_POWERPC_BOOK3S_64_PGTABLE_H_
>  #define _ASM_POWERPC_BOOK3S_64_PGTABLE_H_
>  
> -#include <asm-generic/5level-fixup.h>
> +#include <asm-generic/pgtable-nop4d.h>
>  
>  #ifndef __ASSEMBLY__
>  #include <linux/mmdebug.h>
> @@ -251,7 +251,7 @@ extern unsigned long __pmd_frag_size_shift;
>  /* Bits to mask out from a PUD to get to the PMD page */
>  #define PUD_MASKED_BITS              0xc0000000000000ffUL
>  /* Bits to mask out from a PGD to get to the PUD page */
> -#define PGD_MASKED_BITS              0xc0000000000000ffUL
> +#define P4D_MASKED_BITS              0xc0000000000000ffUL
>  
>  /*
>   * Used as an indicator for rcu callback functions
> @@ -949,54 +949,60 @@ static inline bool pud_access_permitted(pud_t pud, bool 
> write)
>       return pte_access_permitted(pud_pte(pud), write);
>  }
>  
> -#define pgd_write(pgd)               pte_write(pgd_pte(pgd))
> +#define __p4d_raw(x) ((p4d_t) { __pgd_raw(x) })
> +static inline __be64 p4d_raw(p4d_t x)
> +{
> +     return pgd_raw(x.pgd);
> +}
> +
> +#define p4d_write(p4d)               pte_write(p4d_pte(p4d))
>  
> -static inline void pgd_clear(pgd_t *pgdp)
> +static inline void p4d_clear(p4d_t *p4dp)
>  {
> -     *pgdp = __pgd(0);
> +     *p4dp = __p4d(0);
>  }
>  
> -static inline int pgd_none(pgd_t pgd)
> +static inline int p4d_none(p4d_t p4d)
>  {
> -     return !pgd_raw(pgd);
> +     return !p4d_raw(p4d);
>  }
>  
> -static inline int pgd_present(pgd_t pgd)
> +static inline int p4d_present(p4d_t p4d)
>  {
> -     return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PRESENT));
> +     return !!(p4d_raw(p4d) & cpu_to_be64(_PAGE_PRESENT));
>  }
>  
> -static inline pte_t pgd_pte(pgd_t pgd)
> +static inline pte_t p4d_pte(p4d_t p4d)
>  {
> -     return __pte_raw(pgd_raw(pgd));
> +     return __pte_raw(p4d_raw(p4d));
>  }
>  
> -static inline pgd_t pte_pgd(pte_t pte)
> +static inline p4d_t pte_p4d(pte_t pte)
>  {
> -     return __pgd_raw(pte_raw(pte));
> +     return __p4d_raw(pte_raw(pte));
>  }
>  
> -static inline int pgd_bad(pgd_t pgd)
> +static inline int p4d_bad(p4d_t p4d)
>  {
>       if (radix_enabled())
> -             return radix__pgd_bad(pgd);
> -     return hash__pgd_bad(pgd);
> +             return radix__p4d_bad(p4d);
> +     return hash__p4d_bad(p4d);
>  }
>  
> -#define pgd_access_permitted pgd_access_permitted
> -static inline bool pgd_access_permitted(pgd_t pgd, bool write)
> +#define p4d_access_permitted p4d_access_permitted
> +static inline bool p4d_access_permitted(p4d_t p4d, bool write)
>  {
> -     return pte_access_permitted(pgd_pte(pgd), write);
> +     return pte_access_permitted(p4d_pte(p4d), write);
>  }
>  
> -extern struct page *pgd_page(pgd_t pgd);
> +extern struct page *p4d_page(p4d_t p4d);
>  
>  /* Pointers in the page table tree are physical addresses */
>  #define __pgtable_ptr_val(ptr)       __pa(ptr)
>  
>  #define pmd_page_vaddr(pmd)  __va(pmd_val(pmd) & ~PMD_MASKED_BITS)
>  #define pud_page_vaddr(pud)  __va(pud_val(pud) & ~PUD_MASKED_BITS)
> -#define pgd_page_vaddr(pgd)  __va(pgd_val(pgd) & ~PGD_MASKED_BITS)
> +#define p4d_page_vaddr(p4d)  __va(p4d_val(p4d) & ~P4D_MASKED_BITS)
>  
>  #define pgd_index(address) (((address) >> (PGDIR_SHIFT)) & (PTRS_PER_PGD - 
> 1))
>  #define pud_index(address) (((address) >> (PUD_SHIFT)) & (PTRS_PER_PUD - 1))
> @@ -1010,8 +1016,8 @@ extern struct page *pgd_page(pgd_t pgd);
>  
>  #define pgd_offset(mm, address)       ((mm)->pgd + pgd_index(address))
>  
> -#define pud_offset(pgdp, addr)       \
> -     (((pud_t *) pgd_page_vaddr(*(pgdp))) + pud_index(addr))
> +#define pud_offset(p4dp, addr)       \
> +     (((pud_t *) p4d_page_vaddr(*(p4dp))) + pud_index(addr))
>  #define pmd_offset(pudp,addr) \
>       (((pmd_t *) pud_page_vaddr(*(pudp))) + pmd_index(addr))
>  #define pte_offset_kernel(dir,addr) \
> @@ -1366,6 +1372,12 @@ static inline bool pud_is_leaf(pud_t pud)
>       return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
>  }
>  
> +#define p4d_is_leaf p4d_is_leaf
> +static inline bool p4d_is_leaf(p4d_t p4d)
> +{
> +     return !!(p4d_raw(p4d) & cpu_to_be64(_PAGE_PTE));
> +}
> +
>  #define pgd_is_leaf pgd_is_leaf
>  static inline bool pgd_is_leaf(pgd_t pgd)
>  {
> diff --git a/arch/powerpc/include/asm/book3s/64/radix.h 
> b/arch/powerpc/include/asm/book3s/64/radix.h
> index d97db3ad9aae..9bca2ac64220 100644
> --- a/arch/powerpc/include/asm/book3s/64/radix.h
> +++ b/arch/powerpc/include/asm/book3s/64/radix.h
> @@ -30,7 +30,7 @@
>  /* Don't have anything in the reserved bits and leaf bits */
>  #define RADIX_PMD_BAD_BITS           0x60000000000000e0UL
>  #define RADIX_PUD_BAD_BITS           0x60000000000000e0UL
> -#define RADIX_PGD_BAD_BITS           0x60000000000000e0UL
> +#define RADIX_P4D_BAD_BITS           0x60000000000000e0UL
>  
>  #define RADIX_PMD_SHIFT              (PAGE_SHIFT + RADIX_PTE_INDEX_SIZE)
>  #define RADIX_PUD_SHIFT              (RADIX_PMD_SHIFT + RADIX_PMD_INDEX_SIZE)
> @@ -227,9 +227,9 @@ static inline int radix__pud_bad(pud_t pud)
>  }
>  
>  
> -static inline int radix__pgd_bad(pgd_t pgd)
> +static inline int radix__p4d_bad(p4d_t p4d)
>  {
> -     return !!(pgd_val(pgd) & RADIX_PGD_BAD_BITS);
> +     return !!(p4d_val(p4d) & RADIX_P4D_BAD_BITS);
>  }
>  
>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h 
> b/arch/powerpc/include/asm/nohash/32/pgtable.h
> index 552b96eef0c8..a0edcc7b0700 100644
> --- a/arch/powerpc/include/asm/nohash/32/pgtable.h
> +++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
> @@ -2,7 +2,6 @@
>  #ifndef _ASM_POWERPC_NOHASH_32_PGTABLE_H
>  #define _ASM_POWERPC_NOHASH_32_PGTABLE_H
>  
> -#define __ARCH_USE_5LEVEL_HACK
>  #include <asm-generic/pgtable-nopmd.h>
>  
>  #ifndef __ASSEMBLY__
> diff --git a/arch/powerpc/include/asm/nohash/64/pgalloc.h 
> b/arch/powerpc/include/asm/nohash/64/pgalloc.h
> index b9534a793293..668aee6017e7 100644
> --- a/arch/powerpc/include/asm/nohash/64/pgalloc.h
> +++ b/arch/powerpc/include/asm/nohash/64/pgalloc.h
> @@ -15,7 +15,7 @@ struct vmemmap_backing {
>  };
>  extern struct vmemmap_backing *vmemmap_list;
>  
> -#define pgd_populate(MM, PGD, PUD)   pgd_set(PGD, (unsigned long)PUD)
> +#define p4d_populate(MM, P4D, PUD)   p4d_set(P4D, (unsigned long)PUD)
>  
>  static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
>  {
> diff --git a/arch/powerpc/include/asm/nohash/64/pgtable-4k.h 
> b/arch/powerpc/include/asm/nohash/64/pgtable-4k.h
> index c40ec32b8194..81b1c54e3cf1 100644
> --- a/arch/powerpc/include/asm/nohash/64/pgtable-4k.h
> +++ b/arch/powerpc/include/asm/nohash/64/pgtable-4k.h
> @@ -2,7 +2,7 @@
>  #ifndef _ASM_POWERPC_NOHASH_64_PGTABLE_4K_H
>  #define _ASM_POWERPC_NOHASH_64_PGTABLE_4K_H
>  
> -#include <asm-generic/5level-fixup.h>
> +#include <asm-generic/pgtable-nop4d.h>
>  
>  /*
>   * Entries per page directory level.  The PTE level must use a 64b record
> @@ -45,41 +45,41 @@
>  #define PMD_MASKED_BITS              0
>  /* Bits to mask out from a PUD to get to the PMD page */
>  #define PUD_MASKED_BITS              0
> -/* Bits to mask out from a PGD to get to the PUD page */
> -#define PGD_MASKED_BITS              0
> +/* Bits to mask out from a P4D to get to the PUD page */
> +#define P4D_MASKED_BITS              0
>  
>  
>  /*
>   * 4-level page tables related bits
>   */
>  
> -#define pgd_none(pgd)                (!pgd_val(pgd))
> -#define pgd_bad(pgd)         (pgd_val(pgd) == 0)
> -#define pgd_present(pgd)     (pgd_val(pgd) != 0)
> -#define pgd_page_vaddr(pgd)  (pgd_val(pgd) & ~PGD_MASKED_BITS)
> +#define p4d_none(p4d)                (!p4d_val(p4d))
> +#define p4d_bad(p4d)         (p4d_val(p4d) == 0)
> +#define p4d_present(p4d)     (p4d_val(p4d) != 0)
> +#define p4d_page_vaddr(p4d)  (p4d_val(p4d) & ~P4D_MASKED_BITS)
>  
>  #ifndef __ASSEMBLY__
>  
> -static inline void pgd_clear(pgd_t *pgdp)
> +static inline void p4d_clear(p4d_t *p4dp)
>  {
> -     *pgdp = __pgd(0);
> +     *p4dp = __p4d(0);
>  }
>  
> -static inline pte_t pgd_pte(pgd_t pgd)
> +static inline pte_t p4d_pte(p4d_t p4d)
>  {
> -     return __pte(pgd_val(pgd));
> +     return __pte(p4d_val(p4d));
>  }
>  
> -static inline pgd_t pte_pgd(pte_t pte)
> +static inline p4d_t pte_p4d(pte_t pte)
>  {
> -     return __pgd(pte_val(pte));
> +     return __p4d(pte_val(pte));
>  }
> -extern struct page *pgd_page(pgd_t pgd);
> +extern struct page *p4d_page(p4d_t p4d);
>  
>  #endif /* !__ASSEMBLY__ */
>  
> -#define pud_offset(pgdp, addr)       \
> -  (((pud_t *) pgd_page_vaddr(*(pgdp))) + \
> +#define pud_offset(p4dp, addr)       \
> +  (((pud_t *) p4d_page_vaddr(*(p4dp))) + \
>      (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1)))
>  
>  #define pud_ERROR(e) \
> diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h 
> b/arch/powerpc/include/asm/nohash/64/pgtable.h
> index 9a33b8bd842d..b360f262b9c6 100644
> --- a/arch/powerpc/include/asm/nohash/64/pgtable.h
> +++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
> @@ -175,11 +175,11 @@ static inline pud_t pte_pud(pte_t pte)
>       return __pud(pte_val(pte));
>  }
>  #define pud_write(pud)               pte_write(pud_pte(pud))
> -#define pgd_write(pgd)               pte_write(pgd_pte(pgd))
> +#define p4d_write(pgd)               pte_write(p4d_pte(p4d))
>  
> -static inline void pgd_set(pgd_t *pgdp, unsigned long val)
> +static inline void p4d_set(p4d_t *p4dp, unsigned long val)
>  {
> -     *pgdp = __pgd(val);
> +     *p4dp = __p4d(val);
>  }
>  
>  /*
> diff --git a/arch/powerpc/include/asm/pgtable.h 
> b/arch/powerpc/include/asm/pgtable.h
> index 0e4ec8cc37b7..f831b4d866c3 100644
> --- a/arch/powerpc/include/asm/pgtable.h
> +++ b/arch/powerpc/include/asm/pgtable.h
> @@ -145,6 +145,14 @@ static inline bool pud_is_leaf(pud_t pud)
>  }
>  #endif
>  
> +#ifndef p4d_is_leaf
> +#define p4d_is_leaf p4d_is_leaf
> +static inline bool p4d_is_leaf(p4d_t p4d)
> +{
> +     return false;
> +}
> +#endif
> +
>  #ifndef pgd_is_leaf
>  #define pgd_is_leaf pgd_is_leaf
>  static inline bool pgd_is_leaf(pgd_t pgd)
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c 
> b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> index da857c8ba6e4..28e166cbd963 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> @@ -496,17 +496,39 @@ static void kvmppc_unmap_free_pud(struct kvm *kvm, 
> pud_t *pud,
>       pud_free(kvm->mm, pud);
>  }
>  
> +static void kvmppc_unmap_free_p4d(struct kvm *kvm, p4d_t *p4d,
> +                               unsigned int lpid)
> +{
> +     unsigned long iu;
> +     p4d_t *p = p4d;
> +
> +     for (iu = 0; iu < PTRS_PER_P4D; ++iu, ++p) {
> +             if (!p4d_present(*p))
> +                     continue;
> +             if (p4d_is_leaf(*p)) {
> +                     p4d_clear(p);
> +             } else {
> +                     pud_t *pud;
> +
> +                     pud = pud_offset(p, 0);
> +                     kvmppc_unmap_free_pud(kvm, pud, lpid);
> +                     p4d_clear(p);
> +             }
> +     }
> +     p4d_free(kvm->mm, p4d);
> +}
> +
>  void kvmppc_free_pgtable_radix(struct kvm *kvm, pgd_t *pgd, unsigned int 
> lpid)
>  {
>       unsigned long ig;
>  
>       for (ig = 0; ig < PTRS_PER_PGD; ++ig, ++pgd) {
> -             pud_t *pud;
> +             p4d_t *p4d;
>  
>               if (!pgd_present(*pgd))
>                       continue;
> -             pud = pud_offset(pgd, 0);
> -             kvmppc_unmap_free_pud(kvm, pud, lpid);
> +             p4d = p4d_offset(pgd, 0);
> +             kvmppc_unmap_free_p4d(kvm, p4d, lpid);
>               pgd_clear(pgd);
>       }
>  }
> @@ -568,6 +590,7 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, 
> pte_t pte,
>                     unsigned long *rmapp, struct rmap_nested **n_rmap)
>  {
>       pgd_t *pgd;
> +     p4d_t *p4d, *new_p4d = NULL;
>       pud_t *pud, *new_pud = NULL;
>       pmd_t *pmd, *new_pmd = NULL;
>       pte_t *ptep, *new_ptep = NULL;
> @@ -575,9 +598,15 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, 
> pte_t pte,
>  
>       /* Traverse the guest's 2nd-level tree, allocate new levels needed */
>       pgd = pgtable + pgd_index(gpa);
> -     pud = NULL;
> +     p4d = NULL;
>       if (pgd_present(*pgd))
> -             pud = pud_offset(pgd, gpa);
> +             p4d = p4d_offset(pgd, gpa);
> +     else
> +             new_p4d = p4d_alloc_one(kvm->mm, gpa);
> +
> +     pud = NULL;
> +     if (p4d_present(*p4d))
> +             pud = pud_offset(p4d, gpa);
>       else
>               new_pud = pud_alloc_one(kvm->mm, gpa);
>  
> @@ -599,12 +628,18 @@ int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, 
> pte_t pte,
>       /* Now traverse again under the lock and change the tree */
>       ret = -ENOMEM;
>       if (pgd_none(*pgd)) {
> +             if (!new_p4d)
> +                     goto out_unlock;
> +             pgd_populate(kvm->mm, pgd, new_p4d);
> +             new_p4d = NULL;
> +     }
> +     if (p4d_none(*p4d)) {
>               if (!new_pud)
>                       goto out_unlock;
> -             pgd_populate(kvm->mm, pgd, new_pud);
> +             p4d_populate(kvm->mm, p4d, new_pud);
>               new_pud = NULL;
>       }
> -     pud = pud_offset(pgd, gpa);
> +     pud = pud_offset(p4d, gpa);
>       if (pud_is_leaf(*pud)) {
>               unsigned long hgpa = gpa & PUD_MASK;
>  
> @@ -1222,6 +1257,7 @@ static ssize_t debugfs_radix_read(struct file *file, 
> char __user *buf,
>       pgd_t *pgt;
>       struct kvm_nested_guest *nested;
>       pgd_t pgd, *pgdp;
> +     p4d_t p4d, *p4dp;
>       pud_t pud, *pudp;
>       pmd_t pmd, *pmdp;
>       pte_t *ptep;
> @@ -1300,7 +1336,14 @@ static ssize_t debugfs_radix_read(struct file *file, 
> char __user *buf,
>                       continue;
>               }
>  
> -             pudp = pud_offset(&pgd, gpa);
> +             p4dp = p4d_offset(&pgd, gpa);
> +             p4d = READ_ONCE(*p4dp);
> +             if (!(p4d_val(p4d) & _PAGE_PRESENT)) {
> +                     gpa = (gpa & P4D_MASK) + P4D_SIZE;
> +                     continue;
> +             }
> +
> +             pudp = pud_offset(&p4d, gpa);
>               pud = READ_ONCE(*pudp);
>               if (!(pud_val(pud) & _PAGE_PRESENT)) {
>                       gpa = (gpa & PUD_MASK) + PUD_SIZE;
> diff --git a/arch/powerpc/lib/code-patching.c 
> b/arch/powerpc/lib/code-patching.c
> index 3345f039a876..7a59f6863cec 100644
> --- a/arch/powerpc/lib/code-patching.c
> +++ b/arch/powerpc/lib/code-patching.c
> @@ -107,13 +107,18 @@ static inline int unmap_patch_area(unsigned long addr)
>       pte_t *ptep;
>       pmd_t *pmdp;
>       pud_t *pudp;
> +     p4d_t *p4dp;
>       pgd_t *pgdp;
>  
>       pgdp = pgd_offset_k(addr);
>       if (unlikely(!pgdp))
>               return -EINVAL;
>  
> -     pudp = pud_offset(pgdp, addr);
> +     p4dp = p4d_offset(pgdp, addr);
> +     if (unlikely(!p4dp))
> +             return -EINVAL;
> +
> +     pudp = pud_offset(p4dp, addr);
>       if (unlikely(!pudp))
>               return -EINVAL;
>  
> diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
> index 69b2419accef..7479960dc434 100644
> --- a/arch/powerpc/mm/book3s32/mmu.c
> +++ b/arch/powerpc/mm/book3s32/mmu.c
> @@ -312,7 +312,7 @@ void hash_preload(struct mm_struct *mm, unsigned long ea)
>  
>       if (!Hash)
>               return;
> -     pmd = pmd_offset(pud_offset(pgd_offset(mm, ea), ea), ea);
> +     pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, ea), ea), ea), 
> ea);
>       if (!pmd_none(*pmd))
>               add_hash_page(mm->context.id, ea, pmd_val(*pmd));
>  }
> diff --git a/arch/powerpc/mm/book3s32/tlb.c b/arch/powerpc/mm/book3s32/tlb.c
> index 2fcd321040ff..175bc33b41b7 100644
> --- a/arch/powerpc/mm/book3s32/tlb.c
> +++ b/arch/powerpc/mm/book3s32/tlb.c
> @@ -87,7 +87,7 @@ static void flush_range(struct mm_struct *mm, unsigned long 
> start,
>       if (start >= end)
>               return;
>       end = (end - 1) | ~PAGE_MASK;
> -     pmd = pmd_offset(pud_offset(pgd_offset(mm, start), start), start);
> +     pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, start), start), 
> start), start);
>       for (;;) {
>               pmd_end = ((start + PGDIR_SIZE) & PGDIR_MASK) - 1;
>               if (pmd_end > end)
> @@ -145,7 +145,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned 
> long vmaddr)
>               return;
>       }
>       mm = (vmaddr < TASK_SIZE)? vma->vm_mm: &init_mm;
> -     pmd = pmd_offset(pud_offset(pgd_offset(mm, vmaddr), vmaddr), vmaddr);
> +     pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, vmaddr), vmaddr), 
> vmaddr), vmaddr);
>       if (!pmd_none(*pmd))
>               flush_hash_pages(mm->context.id, vmaddr, pmd_val(*pmd), 1);
>  }
> diff --git a/arch/powerpc/mm/book3s64/hash_pgtable.c 
> b/arch/powerpc/mm/book3s64/hash_pgtable.c
> index 64733b9cb20a..9cd15937e88a 100644
> --- a/arch/powerpc/mm/book3s64/hash_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/hash_pgtable.c
> @@ -148,6 +148,7 @@ void hash__vmemmap_remove_mapping(unsigned long start,
>  int hash__map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
>  {
>       pgd_t *pgdp;
> +     p4d_t *p4dp;
>       pud_t *pudp;
>       pmd_t *pmdp;
>       pte_t *ptep;
> @@ -155,7 +156,8 @@ int hash__map_kernel_page(unsigned long ea, unsigned long 
> pa, pgprot_t prot)
>       BUILD_BUG_ON(TASK_SIZE_USER64 > H_PGTABLE_RANGE);
>       if (slab_is_available()) {
>               pgdp = pgd_offset_k(ea);
> -             pudp = pud_alloc(&init_mm, pgdp, ea);
> +             p4dp = p4d_offset(pgdp, ea);
> +             pudp = pud_alloc(&init_mm, p4dp, ea);
>               if (!pudp)
>                       return -ENOMEM;
>               pmdp = pmd_alloc(&init_mm, pudp, ea);
> diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c 
> b/arch/powerpc/mm/book3s64/radix_pgtable.c
> index 974109bb85db..c02427eab084 100644
> --- a/arch/powerpc/mm/book3s64/radix_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
> @@ -64,17 +64,24 @@ static int early_map_kernel_page(unsigned long ea, 
> unsigned long pa,
>  {
>       unsigned long pfn = pa >> PAGE_SHIFT;
>       pgd_t *pgdp;
> +     p4d_t *p4dp;
>       pud_t *pudp;
>       pmd_t *pmdp;
>       pte_t *ptep;
>  
>       pgdp = pgd_offset_k(ea);
>       if (pgd_none(*pgdp)) {
> +             p4dp = early_alloc_pgtable(PGD_TABLE_SIZE, nid,
> +                                             region_start, region_end);
> +             pgd_populate(&init_mm, pgdp, p4dp);
> +     }
> +     p4dp = p4d_offset(pgdp, ea);
> +     if (p4d_none(*p4dp)) {
>               pudp = early_alloc_pgtable(PUD_TABLE_SIZE, nid,
>                                               region_start, region_end);
> -             pgd_populate(&init_mm, pgdp, pudp);
> +             p4d_populate(&init_mm, p4dp, pudp);
>       }
> -     pudp = pud_offset(pgdp, ea);
> +     pudp = pud_offset(p4dp, ea);
>       if (map_page_size == PUD_SIZE) {
>               ptep = (pte_t *)pudp;
>               goto set_the_pte;
> @@ -114,6 +121,7 @@ static int __map_kernel_page(unsigned long ea, unsigned 
> long pa,
>  {
>       unsigned long pfn = pa >> PAGE_SHIFT;
>       pgd_t *pgdp;
> +     p4d_t *p4dp;
>       pud_t *pudp;
>       pmd_t *pmdp;
>       pte_t *ptep;
> @@ -136,7 +144,8 @@ static int __map_kernel_page(unsigned long ea, unsigned 
> long pa,
>        * boot.
>        */
>       pgdp = pgd_offset_k(ea);
> -     pudp = pud_alloc(&init_mm, pgdp, ea);
> +     p4dp = p4d_offset(pgdp, ea);
> +     pudp = pud_alloc(&init_mm, p4dp, ea);
>       if (!pudp)
>               return -ENOMEM;
>       if (map_page_size == PUD_SIZE) {
> @@ -173,6 +182,7 @@ void radix__change_memory_range(unsigned long start, 
> unsigned long end,
>  {
>       unsigned long idx;
>       pgd_t *pgdp;
> +     p4d_t *p4dp;
>       pud_t *pudp;
>       pmd_t *pmdp;
>       pte_t *ptep;
> @@ -185,7 +195,8 @@ void radix__change_memory_range(unsigned long start, 
> unsigned long end,
>  
>       for (idx = start; idx < end; idx += PAGE_SIZE) {
>               pgdp = pgd_offset_k(idx);
> -             pudp = pud_alloc(&init_mm, pgdp, idx);
> +             p4dp = p4d_offset(pgdp, idx);
> +             pudp = pud_alloc(&init_mm, p4dp, idx);
>               if (!pudp)
>                       continue;
>               if (pud_is_leaf(*pudp)) {
> diff --git a/arch/powerpc/mm/book3s64/subpage_prot.c 
> b/arch/powerpc/mm/book3s64/subpage_prot.c
> index 2ef24a53f4c9..27daeed1a141 100644
> --- a/arch/powerpc/mm/book3s64/subpage_prot.c
> +++ b/arch/powerpc/mm/book3s64/subpage_prot.c
> @@ -54,6 +54,7 @@ static void hpte_flush_range(struct mm_struct *mm, unsigned 
> long addr,
>                            int npages)
>  {
>       pgd_t *pgd;
> +     p4d_t *p4d;
>       pud_t *pud;
>       pmd_t *pmd;
>       pte_t *pte;
> @@ -62,7 +63,10 @@ static void hpte_flush_range(struct mm_struct *mm, 
> unsigned long addr,
>       pgd = pgd_offset(mm, addr);
>       if (pgd_none(*pgd))
>               return;
> -     pud = pud_offset(pgd, addr);
> +     p4d = p4d_offset(pgd, addr);
> +     if (p4d_none(*p4d))
> +             return;
> +     pud = pud_offset(p4d, addr);
>       if (pud_none(*pud))
>               return;
>       pmd = pmd_offset(pud, addr);
> diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
> index 73d4873fc7f8..43d463f20fc3 100644
> --- a/arch/powerpc/mm/hugetlbpage.c
> +++ b/arch/powerpc/mm/hugetlbpage.c
> @@ -112,6 +112,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t 
> *hpdp,
>  pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned 
> long sz)
>  {
>       pgd_t *pg;
> +     p4d_t *p4;
>       pud_t *pu;
>       pmd_t *pm;
>       hugepd_t *hpdp = NULL;
> @@ -121,20 +122,21 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned 
> long addr, unsigned long sz
>  
>       addr &= ~(sz-1);
>       pg = pgd_offset(mm, addr);
> +     p4 = p4d_offset(pg, addr);
>  
>  #ifdef CONFIG_PPC_BOOK3S_64
>       if (pshift == PGDIR_SHIFT)
>               /* 16GB huge page */
> -             return (pte_t *) pg;
> +             return (pte_t *) p4;
>       else if (pshift > PUD_SHIFT) {
>               /*
>                * We need to use hugepd table
>                */
>               ptl = &mm->page_table_lock;
> -             hpdp = (hugepd_t *)pg;
> +             hpdp = (hugepd_t *)p4;
>       } else {
>               pdshift = PUD_SHIFT;
> -             pu = pud_alloc(mm, pg, addr);
> +             pu = pud_alloc(mm, p4, addr);
>               if (!pu)
>                       return NULL;
>               if (pshift == PUD_SHIFT)
> @@ -159,10 +161,10 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned 
> long addr, unsigned long sz
>  #else
>       if (pshift >= PGDIR_SHIFT) {
>               ptl = &mm->page_table_lock;
> -             hpdp = (hugepd_t *)pg;
> +             hpdp = (hugepd_t *)p4;
>       } else {
>               pdshift = PUD_SHIFT;
> -             pu = pud_alloc(mm, pg, addr);
> +             pu = pud_alloc(mm, p4, addr);
>               if (!pu)
>                       return NULL;
>               if (pshift >= PUD_SHIFT) {
> @@ -384,7 +386,7 @@ static void hugetlb_free_pmd_range(struct mmu_gather 
> *tlb, pud_t *pud,
>       mm_dec_nr_pmds(tlb->mm);
>  }
>  
> -static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
> +static void hugetlb_free_pud_range(struct mmu_gather *tlb, p4d_t *p4d,
>                                  unsigned long addr, unsigned long end,
>                                  unsigned long floor, unsigned long ceiling)
>  {
> @@ -394,7 +396,7 @@ static void hugetlb_free_pud_range(struct mmu_gather 
> *tlb, pgd_t *pgd,
>  
>       start = addr;
>       do {
> -             pud = pud_offset(pgd, addr);
> +             pud = pud_offset(p4d, addr);
>               next = pud_addr_end(addr, end);
>               if (!is_hugepd(__hugepd(pud_val(*pud)))) {
>                       if (pud_none_or_clear_bad(pud))
> @@ -429,8 +431,8 @@ static void hugetlb_free_pud_range(struct mmu_gather 
> *tlb, pgd_t *pgd,
>       if (end - 1 > ceiling - 1)
>               return;
>  
> -     pud = pud_offset(pgd, start);
> -     pgd_clear(pgd);
> +     pud = pud_offset(p4d, start);
> +     p4d_clear(p4d);
>       pud_free_tlb(tlb, pud, start);
>       mm_dec_nr_puds(tlb->mm);
>  }
> @@ -443,6 +445,7 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
>                           unsigned long floor, unsigned long ceiling)
>  {
>       pgd_t *pgd;
> +     p4d_t *p4d;
>       unsigned long next;
>  
>       /*
> @@ -465,10 +468,11 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
>       do {
>               next = pgd_addr_end(addr, end);
>               pgd = pgd_offset(tlb->mm, addr);
> +             p4d = p4d_offset(pgd, addr);
>               if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
> -                     if (pgd_none_or_clear_bad(pgd))
> +                     if (p4d_none_or_clear_bad(p4d))
>                               continue;
> -                     hugetlb_free_pud_range(tlb, pgd, addr, next, floor, 
> ceiling);
> +                     hugetlb_free_pud_range(tlb, p4d, addr, next, floor, 
> ceiling);
>               } else {
>                       unsigned long more;
>                       /*
> @@ -481,7 +485,7 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
>                       if (more > next)
>                               next = more;
>  
> -                     free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
> +                     free_hugepd_range(tlb, (hugepd_t *)p4d, PGDIR_SHIFT,
>                                         addr, next, floor, ceiling);
>               }
>       } while (addr = next, addr != end);
> diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c 
> b/arch/powerpc/mm/kasan/kasan_init_32.c
> index 0e6ed4413eea..cac0452cbe1f 100644
> --- a/arch/powerpc/mm/kasan/kasan_init_32.c
> +++ b/arch/powerpc/mm/kasan/kasan_init_32.c
> @@ -36,7 +36,7 @@ static int __ref kasan_init_shadow_page_tables(unsigned 
> long k_start, unsigned l
>       unsigned long k_cur, k_next;
>       pgprot_t prot = slab_is_available() ? kasan_prot_ro() : PAGE_KERNEL;
>  
> -     pmd = pmd_offset(pud_offset(pgd_offset_k(k_start), k_start), k_start);
> +     pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset_k(k_start), k_start), 
> k_start), k_start);
>  
>       for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd++) {
>               pte_t *new;
> @@ -94,7 +94,7 @@ static int __ref kasan_init_region(void *start, size_t size)
>               block = memblock_alloc(k_end - k_start, PAGE_SIZE);
>  
>       for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) {
> -             pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(k_cur), k_cur), 
> k_cur);
> +             pmd_t *pmd = 
> pmd_offset(pud_offset(p4d_offset(pgd_offset_k(k_cur), k_cur), k_cur), k_cur);
>               void *va = block ? block + k_cur - k_start : 
> kasan_get_one_page();
>               pte_t pte = pfn_pte(PHYS_PFN(__pa(va)), PAGE_KERNEL);
>  
> @@ -118,7 +118,7 @@ static void __init kasan_remap_early_shadow_ro(void)
>       kasan_populate_pte(kasan_early_shadow_pte, prot);
>  
>       for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) {
> -             pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(k_cur), k_cur), 
> k_cur);
> +             pmd_t *pmd = 
> pmd_offset(pud_offset(p4d_offset(pgd_offset_k(k_cur), k_cur), k_cur), k_cur);
>               pte_t *ptep = pte_offset_kernel(pmd, k_cur);
>  
>               if ((pte_val(*ptep) & PTE_RPN_MASK) != pa)
> @@ -205,7 +205,7 @@ void __init kasan_early_init(void)
>       unsigned long addr = KASAN_SHADOW_START;
>       unsigned long end = KASAN_SHADOW_END;
>       unsigned long next;
> -     pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(addr), addr), addr);
> +     pmd_t *pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset_k(addr), 
> addr), addr), addr);
>  
>       BUILD_BUG_ON(KASAN_SHADOW_START & ~PGDIR_MASK);
>  
> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
> index 9488b63dfc87..ed2e24e493b9 100644
> --- a/arch/powerpc/mm/mem.c
> +++ b/arch/powerpc/mm/mem.c
> @@ -68,8 +68,8 @@ EXPORT_SYMBOL(kmap_prot);
>  
>  static inline pte_t *virt_to_kpte(unsigned long vaddr)
>  {
> -     return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
> -                     vaddr), vaddr), vaddr);
> +     return 
> pte_offset_kernel(pmd_offset(pud_offset(p4d_offset(pgd_offset_k(vaddr),
> +                     vaddr), vaddr), vaddr), vaddr);
>  }
>  #endif
>  
> diff --git a/arch/powerpc/mm/nohash/40x.c b/arch/powerpc/mm/nohash/40x.c
> index f348104eb461..7aaf7155e350 100644
> --- a/arch/powerpc/mm/nohash/40x.c
> +++ b/arch/powerpc/mm/nohash/40x.c
> @@ -104,7 +104,7 @@ unsigned long __init mmu_mapin_ram(unsigned long base, 
> unsigned long top)
>               pmd_t *pmdp;
>               unsigned long val = p | _PMD_SIZE_16M | _PAGE_EXEC | 
> _PAGE_HWWRITE;
>  
> -             pmdp = pmd_offset(pud_offset(pgd_offset_k(v), v), v);
> +             pmdp = pmd_offset(pud_offset(p4d_offset(pgd_offset_k(v), v), 
> v), v);
>               *pmdp++ = __pmd(val);
>               *pmdp++ = __pmd(val);
>               *pmdp++ = __pmd(val);
> @@ -119,7 +119,7 @@ unsigned long __init mmu_mapin_ram(unsigned long base, 
> unsigned long top)
>               pmd_t *pmdp;
>               unsigned long val = p | _PMD_SIZE_4M | _PAGE_EXEC | 
> _PAGE_HWWRITE;
>  
> -             pmdp = pmd_offset(pud_offset(pgd_offset_k(v), v), v);
> +             pmdp = pmd_offset(pud_offset(p4d_offset(pgd_offset_k(v), v), 
> v), v);
>               *pmdp = __pmd(val);
>  
>               v += LARGE_PAGE_SIZE_4M;
> diff --git a/arch/powerpc/mm/nohash/book3e_pgtable.c 
> b/arch/powerpc/mm/nohash/book3e_pgtable.c
> index 4637fdd469cf..a62d59a928be 100644
> --- a/arch/powerpc/mm/nohash/book3e_pgtable.c
> +++ b/arch/powerpc/mm/nohash/book3e_pgtable.c
> @@ -73,6 +73,7 @@ static void __init *early_alloc_pgtable(unsigned long size)
>  int __ref map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
>  {
>       pgd_t *pgdp;
> +     p4d_t *p4dp;
>       pud_t *pudp;
>       pmd_t *pmdp;
>       pte_t *ptep;
> @@ -80,7 +81,10 @@ int __ref map_kernel_page(unsigned long ea, unsigned long 
> pa, pgprot_t prot)
>       BUILD_BUG_ON(TASK_SIZE_USER64 > PGTABLE_RANGE);
>       if (slab_is_available()) {
>               pgdp = pgd_offset_k(ea);
> -             pudp = pud_alloc(&init_mm, pgdp, ea);
> +             p4dp = p4d_alloc(&init_mm, pgdp, ea);
> +             if (!p4dp)
> +                     return -ENOMEM;
> +             pudp = pud_alloc(&init_mm, p4dp, ea);
>               if (!pudp)
>                       return -ENOMEM;
>               pmdp = pmd_alloc(&init_mm, pudp, ea);
> @@ -91,13 +95,16 @@ int __ref map_kernel_page(unsigned long ea, unsigned long 
> pa, pgprot_t prot)
>                       return -ENOMEM;
>       } else {
>               pgdp = pgd_offset_k(ea);
> -#ifndef __PAGETABLE_PUD_FOLDED
>               if (pgd_none(*pgdp)) {
>                       pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
>                       pgd_populate(&init_mm, pgdp, pudp);
>               }
> -#endif /* !__PAGETABLE_PUD_FOLDED */
> -             pudp = pud_offset(pgdp, ea);
> +             p4dp = p4d_offset(pgdp, ea);
> +             if (p4d_none(*p4dp)) {
> +                     pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
> +                     p4d_populate(&init_mm, p4dp, pmdp);
> +             }
> +             pudp = pud_offset(p4dp, ea);
>               if (pud_none(*pudp)) {
>                       pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
>                       pud_populate(&init_mm, pudp, pmdp);
> diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
> index e3759b69f81b..dca6a72da26a 100644
> --- a/arch/powerpc/mm/pgtable.c
> +++ b/arch/powerpc/mm/pgtable.c
> @@ -265,6 +265,7 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
>  void assert_pte_locked(struct mm_struct *mm, unsigned long addr)
>  {
>       pgd_t *pgd;
> +     p4d_t *p4d;
>       pud_t *pud;
>       pmd_t *pmd;
>  
> @@ -272,7 +273,9 @@ void assert_pte_locked(struct mm_struct *mm, unsigned 
> long addr)
>               return;
>       pgd = mm->pgd + pgd_index(addr);
>       BUG_ON(pgd_none(*pgd));
> -     pud = pud_offset(pgd, addr);
> +     p4d = p4d_offset(pgd, addr);
> +     BUG_ON(p4d_none(*p4d));
> +     pud = pud_offset(p4d, addr);
>       BUG_ON(pud_none(*pud));
>       pmd = pmd_offset(pud, addr);
>       /*
> @@ -313,6 +316,7 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
>                       bool *is_thp, unsigned *hpage_shift)
>  {
>       pgd_t pgd, *pgdp;
> +     p4d_t p4d, *p4dp;
>       pud_t pud, *pudp;
>       pmd_t pmd, *pmdp;
>       pte_t *ret_pte;
> @@ -346,13 +350,30 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
>               goto out_huge;
>       }
>  
> +     pdshift = P4D_SHIFT;
> +     p4dp = p4d_offset(&pgd, ea);
> +     p4d  = READ_ONCE(*p4dp);
> +
> +     if (p4d_none(p4d))
> +             return NULL;
> +
> +     if (p4d_is_leaf(p4d)) {
> +             ret_pte = (pte_t *)p4dp;
> +             goto out;
> +     }
> +
> +     if (is_hugepd(__hugepd(p4d_val(p4d)))) {
> +             hpdp = (hugepd_t *)&p4d;
> +             goto out_huge;
> +     }
> +
>       /*
>        * Even if we end up with an unmap, the pgtable will not
>        * be freed, because we do an rcu free and here we are
>        * irq disabled
>        */
>       pdshift = PUD_SHIFT;
> -     pudp = pud_offset(&pgd, ea);
> +     pudp = pud_offset(&p4d, ea);
>       pud  = READ_ONCE(*pudp);
>  
>       if (pud_none(pud))
> diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
> index 73b84166d06a..50d97127a801 100644
> --- a/arch/powerpc/mm/pgtable_32.c
> +++ b/arch/powerpc/mm/pgtable_32.c
> @@ -63,7 +63,7 @@ int __ref map_kernel_page(unsigned long va, phys_addr_t pa, 
> pgprot_t prot)
>       int err = -ENOMEM;
>  
>       /* Use upper 10 bits of VA to index the first level map */
> -     pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
> +     pd = pmd_offset(pud_offset(p4d_offset(pgd_offset_k(va), va), va), va);
>       /* Use middle 10 bits of VA to index the second-level map */
>       if (likely(slab_is_available()))
>               pg = pte_alloc_kernel(pd, va);
> @@ -130,6 +130,7 @@ static int
>  get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t 
> **pmdp)
>  {
>          pgd_t        *pgd;
> +     p4d_t   *p4d;
>       pud_t   *pud;
>          pmd_t        *pmd;
>          pte_t        *pte;
> @@ -137,17 +138,20 @@ get_pteptr(struct mm_struct *mm, unsigned long addr, 
> pte_t **ptep, pmd_t **pmdp)
>  
>          pgd = pgd_offset(mm, addr & PAGE_MASK);
>          if (pgd) {
> -             pud = pud_offset(pgd, addr & PAGE_MASK);
> -             if (pud && pud_present(*pud)) {
> -                     pmd = pmd_offset(pud, addr & PAGE_MASK);
> -                     if (pmd_present(*pmd)) {
> -                             pte = pte_offset_map(pmd, addr & PAGE_MASK);
> -                             if (pte) {
> -                                     retval = 1;
> -                                     *ptep = pte;
> -                                     if (pmdp)
> -                                             *pmdp = pmd;
> -                                     /* XXX caller needs to do pte_unmap, 
> yuck */
> +             p4d = p4d_offset(pgd, addr & PAGE_MASK);
> +             if (p4d && p4d_present(*p4d)) {
> +                     pud = pud_offset(p4d, addr & PAGE_MASK);
> +                     if (pud && pud_present(*pud)) {
> +                             pmd = pmd_offset(pud, addr & PAGE_MASK);
> +                             if (pmd_present(*pmd)) {
> +                                     pte = pte_offset_map(pmd, addr & 
> PAGE_MASK);
> +                                     if (pte) {
> +                                             retval = 1;
> +                                             *ptep = pte;
> +                                             if (pmdp)
> +                                                     *pmdp = pmd;
> +                                             /* XXX caller needs to do 
> pte_unmap, yuck */
> +                                     }
>                               }
>                       }
>               }
> diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
> index e78832dce7bb..1f86a88fd4bb 100644
> --- a/arch/powerpc/mm/pgtable_64.c
> +++ b/arch/powerpc/mm/pgtable_64.c
> @@ -101,13 +101,13 @@ EXPORT_SYMBOL(__pte_frag_size_shift);
>  
>  #ifndef __PAGETABLE_PUD_FOLDED
>  /* 4 level page table */
> -struct page *pgd_page(pgd_t pgd)
> +struct page *p4d_page(p4d_t p4d)
>  {
> -     if (pgd_is_leaf(pgd)) {
> -             VM_WARN_ON(!pgd_huge(pgd));
> -             return pte_page(pgd_pte(pgd));
> +     if (p4d_is_leaf(p4d)) {
> +             VM_WARN_ON(!p4d_huge(p4d));
> +             return pte_page(p4d_pte(p4d));
>       }
> -     return virt_to_page(pgd_page_vaddr(pgd));
> +     return virt_to_page(p4d_page_vaddr(p4d));
>  }
>  #endif
>  
> diff --git a/arch/powerpc/mm/ptdump/hashpagetable.c 
> b/arch/powerpc/mm/ptdump/hashpagetable.c
> index a07278027c6f..ac360ad865a8 100644
> --- a/arch/powerpc/mm/ptdump/hashpagetable.c
> +++ b/arch/powerpc/mm/ptdump/hashpagetable.c
> @@ -417,9 +417,9 @@ static void walk_pmd(struct pg_state *st, pud_t *pud, 
> unsigned long start)
>       }
>  }
>  
> -static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
> +static void walk_pud(struct pg_state *st, p4d_t *p4d, unsigned long start)
>  {
> -     pud_t *pud = pud_offset(pgd, 0);
> +     pud_t *pud = pud_offset(p4d, 0);
>       unsigned long addr;
>       unsigned int i;
>  
> @@ -431,6 +431,20 @@ static void walk_pud(struct pg_state *st, pgd_t *pgd, 
> unsigned long start)
>       }
>  }
>  
> +static void walk_p4d(struct pg_state *st, pgd_t *pgd, unsigned long start)
> +{
> +     p4d_t *p4d = p4d_offset(pgd, 0);
> +     unsigned long addr;
> +     unsigned int i;
> +
> +     for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
> +             addr = start + i * P4D_SIZE;
> +             if (!p4d_none(*p4d))
> +                     /* p4d exists */
> +                     walk_pud(st, p4d, addr);
> +     }
> +}
> +
>  static void walk_pagetables(struct pg_state *st)
>  {
>       pgd_t *pgd = pgd_offset_k(0UL);
> @@ -445,7 +459,7 @@ static void walk_pagetables(struct pg_state *st)
>               addr = KERN_VIRT_START + i * PGDIR_SIZE;
>               if (!pgd_none(*pgd))
>                       /* pgd exists */
> -                     walk_pud(st, pgd, addr);
> +                     walk_p4d(st, pgd, addr);
>       }
>  }
>  
> diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c
> index 2f9ddc29c535..5c2f3b916ac8 100644
> --- a/arch/powerpc/mm/ptdump/ptdump.c
> +++ b/arch/powerpc/mm/ptdump/ptdump.c
> @@ -273,9 +273,9 @@ static void walk_pmd(struct pg_state *st, pud_t *pud, 
> unsigned long start)
>       }
>  }
>  
> -static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
> +static void walk_pud(struct pg_state *st, p4d_t *p4d, unsigned long start)
>  {
> -     pud_t *pud = pud_offset(pgd, 0);
> +     pud_t *pud = pud_offset(p4d, 0);
>       unsigned long addr;
>       unsigned int i;
>  
> @@ -289,6 +289,22 @@ static void walk_pud(struct pg_state *st, pgd_t *pgd, 
> unsigned long start)
>       }
>  }
>  
> +static void walk_p4d(struct pg_state *st, pgd_t *pgd, unsigned long start)
> +{
> +     p4d_t *p4d = p4d_offset(pgd, 0);
> +     unsigned long addr;
> +     unsigned int i;
> +
> +     for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
> +             addr = start + i * P4D_SIZE;
> +             if (!p4d_none(*p4d) && !p4d_is_leaf(*p4d))
> +                     /* p4d exists */
> +                     walk_pud(st, p4d, addr);
> +             else
> +                     note_page(st, addr, 2, p4d_val(*p4d));
> +     }
> +}
> +
>  static void walk_pagetables(struct pg_state *st)
>  {
>       unsigned int i;
> @@ -302,7 +318,7 @@ static void walk_pagetables(struct pg_state *st)
>       for (i = pgd_index(addr); i < PTRS_PER_PGD; i++, pgd++, addr += 
> PGDIR_SIZE) {
>               if (!pgd_none(*pgd) && !pgd_is_leaf(*pgd))
>                       /* pgd exists */
> -                     walk_pud(st, pgd, addr);
> +                     walk_p4d(st, pgd, addr);
>               else
>                       note_page(st, addr, 1, pgd_val(*pgd));
>       }
> diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> index a7056049709e..dd36e10efa65 100644
> --- a/arch/powerpc/xmon/xmon.c
> +++ b/arch/powerpc/xmon/xmon.c
> @@ -3128,6 +3128,7 @@ static void show_pte(unsigned long addr)
>       struct task_struct *tsk = NULL;
>       struct mm_struct *mm;
>       pgd_t *pgdp, *pgdir;
> +     p4d_t *p4dp;
>       pud_t *pudp;
>       pmd_t *pmdp;
>       pte_t *ptep;
> @@ -3172,7 +3173,21 @@ static void show_pte(unsigned long addr)
>       }
>       printf("pgdp @ 0x%px = 0x%016lx\n", pgdp, pgd_val(*pgdp));
>  
> -     pudp = pud_offset(pgdp, addr);
> +     p4dp = p4d_offset(pgdp, addr);
> +
> +     if (p4d_none(*p4dp)) {
> +             printf("No valid P4D\n");
> +             return;
> +     }
> +
> +     if (p4d_is_leaf(*p4dp)) {
> +             format_pte(p4dp, p4d_val(*p4dp));
> +             return;
> +     }
> +
> +     printf("p4dp @ 0x%px = 0x%016lx\n", p4dp, p4d_val(*p4dp));
> +
> +     pudp = pud_offset(p4dp, addr);
>  
>       if (pud_none(*pudp)) {
>               printf("No valid PUD\n");
> -- 
> 2.24.0
> 

-- 
Sincerely yours,
Mike.

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