On Wed, Feb 26, 2020 at 10:46:13AM +0100, Christophe Leroy wrote:
>
>
> Le 26/02/2020 à 10:13, Mike Rapoport a écrit :
> > On Tue, Feb 18, 2020 at 12:54:40PM +0200, Mike Rapoport wrote:
> > > On Sun, Feb 16, 2020 at 11:41:07AM +0100, Christophe Leroy wrote:
> > > >
> > > >
> > > > Le 16/02/2020 à 09:18, Mike Rapoport a écrit :
> > > > > 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.
> > > >
> > > > I don't think it is worth adding all this additionnals walks of p4d,
> > > > this
> > > > patch could be limited to changes like:
> > > >
> > > > - pud = pud_offset(pgd, gpa);
> > > > + pud = pud_offset(p4d_offset(pgd, gpa), gpa);
> > > >
> > > > The additionnal walks should be added through another patch the day
> > > > powerpc
> > > > need them.
> > >
> > > Ok, I'll update the patch to reduce walking the p4d.
> >
> > Here's what I have with more direct acceses from pgd to pud.
>
> I went quickly through. This looks promising.
>
> Do we need the walk_p4d() in arch/powerpc/mm/ptdump/hashpagetable.c ?
> Can't we just do
>
> @@ -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_pud(st, p4d_offset(pgd, addr), addr);
We can do
addr = KERN_VIRT_START + i * PGDIR_SIZE;
p4d = p4d_offset(pgd, addr);
if (!p4d_none(*pgd))
walk_pud()
But I don't think this is really essential. Again, we are trading off code
consistency vs line count. I don't think line count is that important.
> }
> }
>
>
>
> Also, I think the removal of get_pteptr() should be a patch by itself.
>
> You could include my patches in your series. See
> https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=152102
>
> Christophe
>
>
>
> >
> > From 6c59a86ce8394fb6100e9b6ced2e346981fb0ce9 Mon Sep 17 00:00:00 2001
> > From: Mike Rapoport <r...@linux.ibm.com>
> > Date: Sun, 24 Nov 2019 15:38:00 +0200
> > Subject: [PATCH v3] powerpc: add support for folded p4d page tables
> >
> > 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>
> > Tested-by: Christophe Leroy <christophe.le...@c-s.fr> # 8xx and 83xx
> > ---
> > v3:
> > * reduce amount of added p4d walks
> > * kill pgtable_32::get_pteptr and traverse page table in
> > pgtable_32::__change_page_attr_noflush
> >
> >
> > 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 | 60 ++++++++++---------
> > 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 | 6 +-
> > arch/powerpc/kvm/book3s_64_mmu_radix.c | 30 ++++++----
> > 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 | 26 +++++---
> > 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 | 30 ++++++----
> > arch/powerpc/mm/pgtable_32.c | 45 +++-----------
> > arch/powerpc/mm/pgtable_64.c | 10 ++--
> > arch/powerpc/mm/ptdump/hashpagetable.c | 20 ++++++-
> > arch/powerpc/mm/ptdump/ptdump.c | 14 +++--
> > arch/powerpc/xmon/xmon.c | 18 +++---
> > 28 files changed, 213 insertions(+), 184 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h
> > b/arch/powerpc/include/asm/book3s/32/pgtable.h
> > index 5b39c11e884a..39ec11371be0 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 a41e91bd0580..69c5b051734f 100644
> > --- a/arch/powerpc/include/asm/book3s/64/pgalloc.h
> > +++ b/arch/powerpc/include/asm/book3s/64/pgalloc.h
> > @@ -85,9 +85,9 @@ 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 201a69e6a355..fa60e8594b9f 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) \
> > @@ -1368,11 +1374,11 @@ static inline bool pud_is_leaf(pud_t pud)
> > return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
> > }
> > -#define pgd_is_leaf pgd_is_leaf
> > -#define pgd_leaf pgd_is_leaf
> > -static inline bool pgd_is_leaf(pgd_t pgd)
> > +#define p4d_is_leaf p4d_is_leaf
> > +#define p4d_leaf p4d_is_leaf
> > +static inline bool p4d_is_leaf(p4d_t p4d)
> > {
> > - return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PTE));
> > + return !!(p4d_raw(p4d) & cpu_to_be64(_PAGE_PTE));
> > }
> > #endif /* __ASSEMBLY__ */
> > 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 60c4d829152e..d4c2c4259fa3 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 8cc543ed114c..05205d7a7b4a 100644
> > --- a/arch/powerpc/include/asm/pgtable.h
> > +++ b/arch/powerpc/include/asm/pgtable.h
> > @@ -139,9 +139,9 @@ static inline bool pud_is_leaf(pud_t pud)
> > }
> > #endif
> > -#ifndef pgd_is_leaf
> > -#define pgd_is_leaf pgd_is_leaf
> > -static inline bool pgd_is_leaf(pgd_t pgd)
> > +#ifndef p4d_is_leaf
> > +#define p4d_is_leaf p4d_is_leaf
> > +static inline bool p4d_is_leaf(p4d_t p4d)
> > {
> > return false;
> > }
> > diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c
> > b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> > index 803940d79b73..beb694285100 100644
> > --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
> > +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
> > @@ -499,13 +499,14 @@ 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) {
> > + p4d_t *p4d = p4d_offset(pgd, 0);
> > pud_t *pud;
> > - if (!pgd_present(*pgd))
> > + if (!p4d_present(*p4d))
> > continue;
> > - pud = pud_offset(pgd, 0);
> > + pud = pud_offset(p4d, 0);
> > kvmppc_unmap_free_pud(kvm, pud, lpid);
> > - pgd_clear(pgd);
> > + p4d_clear(p4d);
> > }
> > }
> > @@ -566,6 +567,7 @@ 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;
> > pud_t *pud, *new_pud = NULL;
> > pmd_t *pmd, *new_pmd = NULL;
> > pte_t *ptep, *new_ptep = NULL;
> > @@ -573,9 +575,11 @@ 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);
> > + p4d = p4d_offset(pgd, gpa);
> > +
> > pud = NULL;
> > - if (pgd_present(*pgd))
> > - pud = pud_offset(pgd, gpa);
> > + if (p4d_present(*p4d))
> > + pud = pud_offset(p4d, gpa);
> > else
> > new_pud = pud_alloc_one(kvm->mm, gpa);
> > @@ -596,13 +600,13 @@ 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 (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;
> > @@ -1220,6 +1224,7 @@ 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;
> > @@ -1292,13 +1297,14 @@ static ssize_t debugfs_radix_read(struct file
> > *file, char __user *buf,
> > }
> > pgdp = pgt + pgd_index(gpa);
> > - pgd = READ_ONCE(*pgdp);
> > - if (!(pgd_val(pgd) & _PAGE_PRESENT)) {
> > - gpa = (gpa & PGDIR_MASK) + PGDIR_SIZE;
> > + p4dp = p4d_offset(pgdp, gpa);
> > + p4d = READ_ONCE(*p4dp);
> > + if (!(p4d_val(p4d) & _PAGE_PRESENT)) {
> > + gpa = (gpa & P4D_MASK) + P4D_SIZE;
> > continue;
> > }
> > - pudp = pud_offset(&pgd, gpa);
> > + 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 f888cbb109b9..edef17c97206 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 dd1bea45325c..fc3d0b0460b0 100644
> > --- a/arch/powerpc/mm/book3s64/radix_pgtable.c
> > +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
> > @@ -64,17 +64,19 @@ 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 = 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 +116,7 @@ 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 +139,8 @@ 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 +177,7 @@ 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 +190,8 @@ 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)) {
> > @@ -847,6 +853,7 @@ static void __meminit remove_pagetable(unsigned long
> > start, unsigned long end)
> > unsigned long addr, next;
> > pud_t *pud_base;
> > pgd_t *pgd;
> > + p4d_t *p4d;
> > spin_lock(&init_mm.page_table_lock);
> > @@ -854,15 +861,16 @@ static void __meminit remove_pagetable(unsigned long
> > start, unsigned long end)
> > next = pgd_addr_end(addr, end);
> > pgd = pgd_offset_k(addr);
> > - if (!pgd_present(*pgd))
> > + p4d = p4d_offset(pgd, addr);
> > + if (!p4d_present(*p4d))
> > continue;
> > - if (pgd_is_leaf(*pgd)) {
> > - split_kernel_mapping(addr, end, PGDIR_SIZE, (pte_t
> > *)pgd);
> > + if (p4d_is_leaf(*p4d)) {
> > + split_kernel_mapping(addr, end, P4D_SIZE, (pte_t *)p4d);
> > continue;
> > }
> > - pud_base = (pud_t *)pgd_page_vaddr(*pgd);
> > + pud_base = (pud_t *)p4d_page_vaddr(*p4d);
> > remove_pud_table(pud_base, addr, next);
> > }
> > diff --git a/arch/powerpc/mm/book3s64/subpage_prot.c
> > b/arch/powerpc/mm/book3s64/subpage_prot.c
> > index 2ef24a53f4c9..25a0c044bd93 100644
> > --- a/arch/powerpc/mm/book3s64/subpage_prot.c
> > +++ b/arch/powerpc/mm/book3s64/subpage_prot.c
> > @@ -54,15 +54,17 @@ 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;
> > spinlock_t *ptl;
> > pgd = pgd_offset(mm, addr);
> > - if (pgd_none(*pgd))
> > + p4d = p4d_offset(pgd, addr);
> > + if (p4d_none(*p4d))
> > return;
> > - pud = pud_offset(pgd, addr);
> > + 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 33b3461d91e8..54f5994d4cbb 100644
> > --- a/arch/powerpc/mm/hugetlbpage.c
> > +++ b/arch/powerpc/mm/hugetlbpage.c
> > @@ -119,6 +119,7 @@ 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;
> > @@ -128,20 +129,21 @@ 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)
> > @@ -166,10 +168,10 @@ 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) {
> > @@ -390,7 +392,7 @@ 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)
> > {
> > @@ -400,7 +402,7 @@ 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))
> > @@ -435,8 +437,8 @@ 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);
> > }
> > @@ -449,6 +451,7 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
> > unsigned long floor, unsigned long ceiling)
> > {
> > pgd_t *pgd;
> > + p4d_t *p4d;
> > unsigned long next;
> > /*
> > @@ -471,10 +474,11 @@ 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;
> > /*
> > @@ -487,7 +491,7 @@ 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 db5664dde5ff..88e2e16380b5 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 __init kasan_init_shadow_page_tables(unsigned
> > long k_start, unsigned
> > unsigned long k_cur, k_next;
> > pte_t *new = NULL;
> > - 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++) {
> > k_next = pgd_addr_end(k_cur, k_end);
> > @@ -78,7 +78,7 @@ static int __init 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 + k_cur - k_start;
> > pte_t pte = pfn_pte(PHYS_PFN(__pa(va)), PAGE_KERNEL);
> > @@ -102,7 +102,7 @@ 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)
> > @@ -201,7 +201,7 @@ 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 ef7b1119b2e2..8262b384dcf3 100644
> > --- a/arch/powerpc/mm/mem.c
> > +++ b/arch/powerpc/mm/mem.c
> > @@ -69,8 +69,8 @@ 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..77884e24281d 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 +81,8 @@ 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_offset(pgdp, ea);
> > + pudp = pud_alloc(&init_mm, p4dp, ea);
> > if (!pudp)
> > return -ENOMEM;
> > pmdp = pmd_alloc(&init_mm, pudp, ea);
> > @@ -91,13 +93,12 @@ 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);
> > + p4dp = p4d_offset(pgdp, ea);
> > + if (p4d_none(*p4dp)) {
> > + pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
> > + p4d_populate(&init_mm, p4dp, pmdp);
> > }
> > -#endif /* !__PAGETABLE_PUD_FOLDED */
> > - pudp = pud_offset(pgdp, ea);
> > + 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..c2499271f6c1 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);
> > /*
> > @@ -312,12 +315,13 @@ EXPORT_SYMBOL_GPL(vmalloc_to_phys);
> > pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
> > bool *is_thp, unsigned *hpage_shift)
> > {
> > - pgd_t pgd, *pgdp;
> > + pgd_t *pgdp;
> > + p4d_t p4d, *p4dp;
> > pud_t pud, *pudp;
> > pmd_t pmd, *pmdp;
> > pte_t *ret_pte;
> > hugepd_t *hpdp = NULL;
> > - unsigned pdshift = PGDIR_SHIFT;
> > + unsigned pdshift;
> > if (hpage_shift)
> > *hpage_shift = 0;
> > @@ -325,24 +329,28 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long
> > ea,
> > if (is_thp)
> > *is_thp = false;
> > - pgdp = pgdir + pgd_index(ea);
> > - pgd = READ_ONCE(*pgdp);
> > /*
> > * Always operate on the local stack value. This make sure the
> > * value don't get updated by a parallel THP split/collapse,
> > * page fault or a page unmap. The return pte_t * is still not
> > * stable. So should be checked there for above conditions.
> > + * Top level is an exception because it is folded into p4d.
> > */
> > - if (pgd_none(pgd))
> > + pgdp = pgdir + pgd_index(ea);
> > + p4dp = p4d_offset(pgdp, ea);
> > + p4d = READ_ONCE(*p4dp);
> > + pdshift = P4D_SHIFT;
> > +
> > + if (p4d_none(p4d))
> > return NULL;
> > - if (pgd_is_leaf(pgd)) {
> > - ret_pte = (pte_t *)pgdp;
> > + if (p4d_is_leaf(p4d)) {
> > + ret_pte = (pte_t *)p4dp;
> > goto out;
> > }
> > - if (is_hugepd(__hugepd(pgd_val(pgd)))) {
> > - hpdp = (hugepd_t *)&pgd;
> > + if (is_hugepd(__hugepd(p4d_val(p4d)))) {
> > + hpdp = (hugepd_t *)&p4d;
> > goto out_huge;
> > }
> > @@ -352,7 +360,7 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
> > * 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 5fb90edd865e..5774d4bc94d0 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);
> > @@ -121,53 +121,24 @@ void __init mapin_ram(void)
> > }
> > }
> > -/* Scan the real Linux page tables and return a PTE pointer for
> > - * a virtual address in a context.
> > - * Returns true (1) if PTE was found, zero otherwise. The pointer to
> > - * the PTE pointer is unmodified if PTE is not found.
> > - */
> > -static int
> > -get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t
> > **pmdp)
> > -{
> > - pgd_t *pgd;
> > - pud_t *pud;
> > - pmd_t *pmd;
> > - pte_t *pte;
> > - int retval = 0;
> > -
> > - 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 */
> > - }
> > - }
> > - }
> > - }
> > - return(retval);
> > -}
> > -
> > static int __change_page_attr_noflush(struct page *page, pgprot_t prot)
> > {
> > pte_t *kpte;
> > pmd_t *kpmd;
> > - unsigned long address;
> > + unsigned long address, va;
> > BUG_ON(PageHighMem(page));
> > address = (unsigned long)page_address(page);
> > + va = address & PAGE_MASK;
> > if (v_block_mapped(address))
> > return 0;
> > - if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
> > +
> > + kpmd = pmd_offset(pud_offset(p4d_offset(pgd_offset_k(va), va), va), va);
> > + if (!pmd_present(*kpmd))
> > return -EINVAL;
> > +
> > + kpte = pte_offset_map(kpmd, va);
> > __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
> > pte_unmap(kpte);
> > 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 206156255247..9d6256b61df3 100644
> > --- a/arch/powerpc/mm/ptdump/ptdump.c
> > +++ b/arch/powerpc/mm/ptdump/ptdump.c
> > @@ -277,9 +277,9 @@ 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;
> > @@ -304,11 +304,13 @@ static void walk_pagetables(struct pg_state *st)
> > * the hash pagetable.
> > */
> > 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);
> > + p4d_t *p4d = p4d_offset(pgd, 0);
> > +
> > + if (!p4d_none(*p4d) && !p4d_is_leaf(*p4d))
> > + /* p4d exists */
> > + walk_pud(st, p4d, addr);
> > else
> > - note_page(st, addr, 1, pgd_val(*pgd));
> > + note_page(st, addr, 1, p4d_val(*p4d));
> > }
> > }
> > diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> > index 0ec9640335bb..3e29128c58cc 100644
> > --- a/arch/powerpc/xmon/xmon.c
> > +++ b/arch/powerpc/xmon/xmon.c
> > @@ -3130,6 +3130,7 @@ 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;
> > @@ -3161,20 +3162,21 @@ static void show_pte(unsigned long addr)
> > pgdir = pgd_offset(mm, 0);
> > }
> > - if (pgd_none(*pgdp)) {
> > - printf("no linux page table for address\n");
> > + p4dp = p4d_offset(pgdp, addr);
> > +
> > + if (p4d_none(*p4dp)) {
> > + printf("No valid P4D\n");
> > return;
> > }
> > - printf("pgd @ 0x%px\n", pgdir);
> > -
> > - if (pgd_is_leaf(*pgdp)) {
> > - format_pte(pgdp, pgd_val(*pgdp));
> > + if (p4d_is_leaf(*p4dp)) {
> > + format_pte(p4dp, p4d_val(*p4dp));
> > return;
> > }
> > - printf("pgdp @ 0x%px = 0x%016lx\n", pgdp, pgd_val(*pgdp));
> > - pudp = pud_offset(pgdp, addr);
> > + 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");
> >
>
>
--
Sincerely yours,
Mike.
