Re: [PATCH v4 03/14] arm64: add support for folded p4d page tables
From: Mike Rapoport
Date: Sat May 16 2020 - 13:20:42 EST
On Fri, May 15, 2020 at 11:40:12AM -0700, Andrew Morton wrote:
> On Tue, 14 Apr 2020 18:34:44 +0300 Mike Rapoport <rppt@xxxxxxxxxx> wrote:
>
> > Implement primitives necessary for the 4th level folding, add walks of p4d
> > level where appropriate, replace 5level-fixup.h with pgtable-nop4d.h and
> > remove __ARCH_USE_5LEVEL_HACK.
>
> This needed some rework due to arm changes in linux-next. Please check
> my handiwork and test it once I've merged this into linux-next?
Looks ok to me. It passed defconfig and a couple of randconfig builds
and qemu-system-aarch64 boots find with this.
> Rejects were
>
> --- arch/arm64/include/asm/pgtable.h~arm64-add-support-for-folded-p4d-page-tables
> +++ arch/arm64/include/asm/pgtable.h
> @@ -596,49 +604,50 @@ static inline phys_addr_t pud_page_paddr
>
> #define pud_ERROR(pud) __pud_error(__FILE__, __LINE__, pud_val(pud))
>
> -#define pgd_none(pgd) (!pgd_val(pgd))
> -#define pgd_bad(pgd) (!(pgd_val(pgd) & 2))
> -#define pgd_present(pgd) (pgd_val(pgd))
> +#define p4d_none(p4d) (!p4d_val(p4d))
> +#define p4d_bad(p4d) (!(p4d_val(p4d) & 2))
> +#define p4d_present(p4d) (p4d_val(p4d))
>
> -static inline void set_pgd(pgd_t *pgdp, pgd_t pgd)
> +static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)
> {
> - if (in_swapper_pgdir(pgdp)) {
> - set_swapper_pgd(pgdp, pgd);
> + if (in_swapper_pgdir(p4dp)) {
> + set_swapper_pgd((pgd_t *)p4dp, __pgd(p4d_val(p4d)));
> return;
> }
>
> - WRITE_ONCE(*pgdp, pgd);
> + WRITE_ONCE(*p4dp, p4d);
> dsb(ishst);
> isb();
> }
>
> -static inline void pgd_clear(pgd_t *pgdp)
> +static inline void p4d_clear(p4d_t *p4dp)
> {
> - set_pgd(pgdp, __pgd(0));
> + set_p4d(p4dp, __p4d(0));
> }
>
> -static inline phys_addr_t pgd_page_paddr(pgd_t pgd)
> +static inline phys_addr_t p4d_page_paddr(p4d_t p4d)
> {
> - return __pgd_to_phys(pgd);
> + return __p4d_to_phys(p4d);
> }
>
> /* Find an entry in the frst-level page table. */
> #define pud_index(addr) (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
>
> -#define pud_offset_phys(dir, addr) (pgd_page_paddr(READ_ONCE(*(dir))) + pud_index(addr) * sizeof(pud_t))
> +#define pud_offset_phys(dir, addr) (p4d_page_paddr(READ_ONCE(*(dir))) + pud_index(addr) * sizeof(pud_t))
> #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr))))
>
> #define pud_set_fixmap(addr) ((pud_t *)set_fixmap_offset(FIX_PUD, addr))
> -#define pud_set_fixmap_offset(pgd, addr) pud_set_fixmap(pud_offset_phys(pgd, addr))
> +#define pud_set_fixmap_offset(p4d, addr) pud_set_fixmap(pud_offset_phys(p4d, addr))
> #define pud_clear_fixmap() clear_fixmap(FIX_PUD)
>
> -#define pgd_page(pgd) pfn_to_page(__phys_to_pfn(__pgd_to_phys(pgd)))
> +#define p4d_page(p4d) pfn_to_page(__phys_to_pfn(__p4d_to_phys(p4d)))
>
> /* use ONLY for statically allocated translation tables */
> #define pud_offset_kimg(dir,addr) ((pud_t *)__phys_to_kimg(pud_offset_phys((dir), (addr))))
>
> #else
>
> +#define p4d_page_paddr(p4d) ({ BUILD_BUG(); 0;})
> #define pgd_page_paddr(pgd) ({ BUILD_BUG(); 0;})
>
> /* Match pud_offset folding in <asm/generic/pgtable-nopud.h> */
>
>
>
> and
>
> --- arch/arm64/kvm/mmu.c~arm64-add-support-for-folded-p4d-page-tables
> +++ arch/arm64/kvm/mmu.c
> @@ -469,7 +517,7 @@ static void stage2_flush_memslot(struct
> do {
> next = stage2_pgd_addr_end(kvm, addr, end);
> if (!stage2_pgd_none(kvm, *pgd))
> - stage2_flush_puds(kvm, pgd, addr, next);
> + stage2_flush_p4ds(kvm, pgd, addr, next);
> } while (pgd++, addr = next, addr != end);
> }
>
>
>
> Result:
>
> From: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> Subject: arm64: add support for folded p4d page tables
>
> Implement primitives necessary for the 4th level folding, add walks of p4d
> level where appropriate, replace 5level-fixup.h with pgtable-nop4d.h and
> remove __ARCH_USE_5LEVEL_HACK.
>
> Link: http://lkml.kernel.org/r/20200414153455.21744-4-rppt@xxxxxxxxxx
> Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Brian Cain <bcain@xxxxxxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Christophe Leroy <christophe.leroy@xxxxxx>
> Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
> Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> Cc: Guan Xuetao <gxt@xxxxxxxxxx>
> Cc: James Morse <james.morse@xxxxxxx>
> Cc: Jonas Bonn <jonas@xxxxxxxxxxxx>
> Cc: Julien Thierry <julien.thierry.kdev@xxxxxxxxx>
> Cc: Ley Foon Tan <ley.foon.tan@xxxxxxxxx>
> Cc: Marc Zyngier <maz@xxxxxxxxxx>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Rich Felker <dalias@xxxxxxxx>
> Cc: Russell King <linux@xxxxxxxxxxxxxxx>
> Cc: Stafford Horne <shorne@xxxxxxxxx>
> Cc: Stefan Kristiansson <stefan.kristiansson@xxxxxxxxxxxxx>
> Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> Cc: Tony Luck <tony.luck@xxxxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> ---
>
> arch/arm64/include/asm/kvm_mmu.h | 10 -
> arch/arm64/include/asm/pgalloc.h | 10 -
> arch/arm64/include/asm/pgtable-types.h | 5
> arch/arm64/include/asm/pgtable.h | 37 ++-
> arch/arm64/include/asm/stage2_pgtable.h | 48 +++--
> arch/arm64/kernel/hibernate.c | 44 +++-
> arch/arm64/kvm/mmu.c | 209 ++++++++++++++++++----
> arch/arm64/mm/fault.c | 9
> arch/arm64/mm/hugetlbpage.c | 15 +
> arch/arm64/mm/kasan_init.c | 26 ++
> arch/arm64/mm/mmu.c | 52 +++--
> arch/arm64/mm/pageattr.c | 7
> 12 files changed, 368 insertions(+), 104 deletions(-)
>
> --- a/arch/arm64/include/asm/kvm_mmu.h~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/include/asm/kvm_mmu.h
> @@ -172,8 +172,8 @@ void kvm_clear_hyp_idmap(void);
> __pmd(__phys_to_pmd_val(__pa(ptep)) | PMD_TYPE_TABLE)
> #define kvm_mk_pud(pmdp) \
> __pud(__phys_to_pud_val(__pa(pmdp)) | PMD_TYPE_TABLE)
> -#define kvm_mk_pgd(pudp) \
> - __pgd(__phys_to_pgd_val(__pa(pudp)) | PUD_TYPE_TABLE)
> +#define kvm_mk_p4d(pmdp) \
> + __p4d(__phys_to_p4d_val(__pa(pmdp)) | PUD_TYPE_TABLE)
>
> #define kvm_set_pud(pudp, pud) set_pud(pudp, pud)
>
> @@ -299,6 +299,12 @@ static inline bool kvm_s2pud_young(pud_t
> #define hyp_pud_table_empty(pudp) kvm_page_empty(pudp)
> #endif
>
> +#ifdef __PAGETABLE_P4D_FOLDED
> +#define hyp_p4d_table_empty(p4dp) (0)
> +#else
> +#define hyp_p4d_table_empty(p4dp) kvm_page_empty(p4dp)
> +#endif
> +
> struct kvm;
>
> #define kvm_flush_dcache_to_poc(a,l) __flush_dcache_area((a), (l))
> --- a/arch/arm64/include/asm/pgalloc.h~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/include/asm/pgalloc.h
> @@ -73,17 +73,17 @@ static inline void pud_free(struct mm_st
> free_page((unsigned long)pudp);
> }
>
> -static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t pudp, pgdval_t prot)
> +static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot)
> {
> - set_pgd(pgdp, __pgd(__phys_to_pgd_val(pudp) | prot));
> + set_p4d(p4dp, __p4d(__phys_to_p4d_val(pudp) | prot));
> }
>
> -static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgdp, pud_t *pudp)
> +static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4dp, pud_t *pudp)
> {
> - __pgd_populate(pgdp, __pa(pudp), PUD_TYPE_TABLE);
> + __p4d_populate(p4dp, __pa(pudp), PUD_TYPE_TABLE);
> }
> #else
> -static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t pudp, pgdval_t prot)
> +static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot)
> {
> BUILD_BUG();
> }
> --- a/arch/arm64/include/asm/pgtable.h~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/include/asm/pgtable.h
> @@ -298,6 +298,11 @@ static inline pte_t pgd_pte(pgd_t pgd)
> return __pte(pgd_val(pgd));
> }
>
> +static inline pte_t p4d_pte(p4d_t p4d)
> +{
> + return __pte(p4d_val(p4d));
> +}
> +
> static inline pte_t pud_pte(pud_t pud)
> {
> return __pte(pud_val(pud));
> @@ -401,6 +406,9 @@ static inline pmd_t pmd_mkdevmap(pmd_t p
>
> #define set_pmd_at(mm, addr, pmdp, pmd) set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))
>
> +#define __p4d_to_phys(p4d) __pte_to_phys(p4d_pte(p4d))
> +#define __phys_to_p4d_val(phys) __phys_to_pte_val(phys)
> +
> #define __pgd_to_phys(pgd) __pte_to_phys(pgd_pte(pgd))
> #define __phys_to_pgd_val(phys) __phys_to_pte_val(phys)
>
> @@ -592,49 +600,50 @@ static inline phys_addr_t pud_page_paddr
>
> #define pud_ERROR(pud) __pud_error(__FILE__, __LINE__, pud_val(pud))
>
> -#define pgd_none(pgd) (!pgd_val(pgd))
> -#define pgd_bad(pgd) (!(pgd_val(pgd) & 2))
> -#define pgd_present(pgd) (pgd_val(pgd))
> +#define p4d_none(p4d) (!p4d_val(p4d))
> +#define p4d_bad(p4d) (!(p4d_val(p4d) & 2))
> +#define p4d_present(p4d) (p4d_val(p4d))
>
> -static inline void set_pgd(pgd_t *pgdp, pgd_t pgd)
> +static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)
> {
> - if (in_swapper_pgdir(pgdp)) {
> - set_swapper_pgd(pgdp, pgd);
> + if (in_swapper_pgdir(p4dp)) {
> + set_swapper_pgd((pgd_t *)p4dp, __pgd(p4d_val(p4d)));
> return;
> }
>
> - WRITE_ONCE(*pgdp, pgd);
> + WRITE_ONCE(*p4dp, p4d);
> dsb(ishst);
> isb();
> }
>
> -static inline void pgd_clear(pgd_t *pgdp)
> +static inline void p4d_clear(p4d_t *p4dp)
> {
> - set_pgd(pgdp, __pgd(0));
> + set_p4d(p4dp, __p4d(0));
> }
>
> -static inline phys_addr_t pgd_page_paddr(pgd_t pgd)
> +static inline phys_addr_t p4d_page_paddr(p4d_t p4d)
> {
> - return __pgd_to_phys(pgd);
> + return __p4d_to_phys(p4d);
> }
>
> /* Find an entry in the frst-level page table. */
> #define pud_index(addr) (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
>
> -#define pud_offset_phys(dir, addr) (pgd_page_paddr(READ_ONCE(*(dir))) + pud_index(addr) * sizeof(pud_t))
> +#define pud_offset_phys(dir, addr) (p4d_page_paddr(READ_ONCE(*(dir))) + pud_index(addr) * sizeof(pud_t))
> #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr))))
>
> #define pud_set_fixmap(addr) ((pud_t *)set_fixmap_offset(FIX_PUD, addr))
> -#define pud_set_fixmap_offset(pgd, addr) pud_set_fixmap(pud_offset_phys(pgd, addr))
> +#define pud_set_fixmap_offset(p4d, addr) pud_set_fixmap(pud_offset_phys(p4d, addr))
> #define pud_clear_fixmap() clear_fixmap(FIX_PUD)
>
> -#define pgd_page(pgd) phys_to_page(__pgd_to_phys(pgd))
> +#define p4d_page(p4d) pfn_to_page(__phys_to_pfn(__p4d_to_phys(p4d)))
>
> /* use ONLY for statically allocated translation tables */
> #define pud_offset_kimg(dir,addr) ((pud_t *)__phys_to_kimg(pud_offset_phys((dir), (addr))))
>
> #else
>
> +#define p4d_page_paddr(p4d) ({ BUILD_BUG(); 0;})
> #define pgd_page_paddr(pgd) ({ BUILD_BUG(); 0;})
>
> /* Match pud_offset folding in <asm/generic/pgtable-nopud.h> */
> --- a/arch/arm64/include/asm/pgtable-types.h~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/include/asm/pgtable-types.h
> @@ -14,6 +14,7 @@
> typedef u64 pteval_t;
> typedef u64 pmdval_t;
> typedef u64 pudval_t;
> +typedef u64 p4dval_t;
> typedef u64 pgdval_t;
>
> /*
> @@ -44,13 +45,11 @@ typedef struct { pteval_t pgprot; } pgpr
> #define __pgprot(x) ((pgprot_t) { (x) } )
>
> #if CONFIG_PGTABLE_LEVELS == 2
> -#define __ARCH_USE_5LEVEL_HACK
> #include <asm-generic/pgtable-nopmd.h>
> #elif CONFIG_PGTABLE_LEVELS == 3
> -#define __ARCH_USE_5LEVEL_HACK
> #include <asm-generic/pgtable-nopud.h>
> #elif CONFIG_PGTABLE_LEVELS == 4
> -#include <asm-generic/5level-fixup.h>
> +#include <asm-generic/pgtable-nop4d.h>
> #endif
>
> #endif /* __ASM_PGTABLE_TYPES_H */
> --- a/arch/arm64/include/asm/stage2_pgtable.h~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/include/asm/stage2_pgtable.h
> @@ -68,41 +68,67 @@ static inline bool kvm_stage2_has_pud(st
> #define S2_PUD_SIZE (1UL << S2_PUD_SHIFT)
> #define S2_PUD_MASK (~(S2_PUD_SIZE - 1))
>
> -static inline bool stage2_pgd_none(struct kvm *kvm, pgd_t pgd)
> +#define stage2_pgd_none(kvm, pgd) pgd_none(pgd)
> +#define stage2_pgd_clear(kvm, pgd) pgd_clear(pgd)
> +#define stage2_pgd_present(kvm, pgd) pgd_present(pgd)
> +#define stage2_pgd_populate(kvm, pgd, p4d) pgd_populate(NULL, pgd, p4d)
> +
> +static inline p4d_t *stage2_p4d_offset(struct kvm *kvm,
> + pgd_t *pgd, unsigned long address)
> +{
> + return p4d_offset(pgd, address);
> +}
> +
> +static inline void stage2_p4d_free(struct kvm *kvm, p4d_t *p4d)
> +{
> +}
> +
> +static inline bool stage2_p4d_table_empty(struct kvm *kvm, p4d_t *p4dp)
> +{
> + return false;
> +}
> +
> +static inline phys_addr_t stage2_p4d_addr_end(struct kvm *kvm,
> + phys_addr_t addr, phys_addr_t end)
> +{
> + return end;
> +}
> +
> +static inline bool stage2_p4d_none(struct kvm *kvm, p4d_t p4d)
> {
> if (kvm_stage2_has_pud(kvm))
> - return pgd_none(pgd);
> + return p4d_none(p4d);
> else
> return 0;
> }
>
> -static inline void stage2_pgd_clear(struct kvm *kvm, pgd_t *pgdp)
> +static inline void stage2_p4d_clear(struct kvm *kvm, p4d_t *p4dp)
> {
> if (kvm_stage2_has_pud(kvm))
> - pgd_clear(pgdp);
> + p4d_clear(p4dp);
> }
>
> -static inline bool stage2_pgd_present(struct kvm *kvm, pgd_t pgd)
> +static inline bool stage2_p4d_present(struct kvm *kvm, p4d_t p4d)
> {
> if (kvm_stage2_has_pud(kvm))
> - return pgd_present(pgd);
> + return p4d_present(p4d);
> else
> return 1;
> }
>
> -static inline void stage2_pgd_populate(struct kvm *kvm, pgd_t *pgd, pud_t *pud)
> +static inline void stage2_p4d_populate(struct kvm *kvm, p4d_t *p4d, pud_t *pud)
> {
> if (kvm_stage2_has_pud(kvm))
> - pgd_populate(NULL, pgd, pud);
> + p4d_populate(NULL, p4d, pud);
> }
>
> static inline pud_t *stage2_pud_offset(struct kvm *kvm,
> - pgd_t *pgd, unsigned long address)
> + p4d_t *p4d, unsigned long address)
> {
> if (kvm_stage2_has_pud(kvm))
> - return pud_offset(pgd, address);
> + return pud_offset(p4d, address);
> else
> - return (pud_t *)pgd;
> + return (pud_t *)p4d;
> }
>
> static inline void stage2_pud_free(struct kvm *kvm, pud_t *pud)
> --- a/arch/arm64/kernel/hibernate.c~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/kernel/hibernate.c
> @@ -184,6 +184,7 @@ static int trans_pgd_map_page(pgd_t *tra
> pgprot_t pgprot)
> {
> pgd_t *pgdp;
> + p4d_t *p4dp;
> pud_t *pudp;
> pmd_t *pmdp;
> pte_t *ptep;
> @@ -196,7 +197,15 @@ static int trans_pgd_map_page(pgd_t *tra
> pgd_populate(&init_mm, pgdp, pudp);
> }
>
> - pudp = pud_offset(pgdp, dst_addr);
> + p4dp = p4d_offset(pgdp, dst_addr);
> + if (p4d_none(READ_ONCE(*p4dp))) {
> + pudp = (void *)get_safe_page(GFP_ATOMIC);
> + if (!pudp)
> + return -ENOMEM;
> + p4d_populate(&init_mm, p4dp, pudp);
> + }
> +
> + pudp = pud_offset(p4dp, dst_addr);
> if (pud_none(READ_ONCE(*pudp))) {
> pmdp = (void *)get_safe_page(GFP_ATOMIC);
> if (!pmdp)
> @@ -419,7 +428,7 @@ static int copy_pmd(pud_t *dst_pudp, pud
> return 0;
> }
>
> -static int copy_pud(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start,
> +static int copy_pud(p4d_t *dst_p4dp, p4d_t *src_p4dp, unsigned long start,
> unsigned long end)
> {
> pud_t *dst_pudp;
> @@ -427,15 +436,15 @@ static int copy_pud(pgd_t *dst_pgdp, pgd
> unsigned long next;
> unsigned long addr = start;
>
> - if (pgd_none(READ_ONCE(*dst_pgdp))) {
> + if (p4d_none(READ_ONCE(*dst_p4dp))) {
> dst_pudp = (pud_t *)get_safe_page(GFP_ATOMIC);
> if (!dst_pudp)
> return -ENOMEM;
> - pgd_populate(&init_mm, dst_pgdp, dst_pudp);
> + p4d_populate(&init_mm, dst_p4dp, dst_pudp);
> }
> - dst_pudp = pud_offset(dst_pgdp, start);
> + dst_pudp = pud_offset(dst_p4dp, start);
>
> - src_pudp = pud_offset(src_pgdp, start);
> + src_pudp = pud_offset(src_p4dp, start);
> do {
> pud_t pud = READ_ONCE(*src_pudp);
>
> @@ -454,6 +463,27 @@ static int copy_pud(pgd_t *dst_pgdp, pgd
> return 0;
> }
>
> +static int copy_p4d(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start,
> + unsigned long end)
> +{
> + p4d_t *dst_p4dp;
> + p4d_t *src_p4dp;
> + unsigned long next;
> + unsigned long addr = start;
> +
> + dst_p4dp = p4d_offset(dst_pgdp, start);
> + src_p4dp = p4d_offset(src_pgdp, start);
> + do {
> + next = p4d_addr_end(addr, end);
> + if (p4d_none(READ_ONCE(*src_p4dp)))
> + continue;
> + if (copy_pud(dst_p4dp, src_p4dp, addr, next))
> + return -ENOMEM;
> + } while (dst_p4dp++, src_p4dp++, addr = next, addr != end);
> +
> + return 0;
> +}
> +
> static int copy_page_tables(pgd_t *dst_pgdp, unsigned long start,
> unsigned long end)
> {
> @@ -466,7 +496,7 @@ static int copy_page_tables(pgd_t *dst_p
> next = pgd_addr_end(addr, end);
> if (pgd_none(READ_ONCE(*src_pgdp)))
> continue;
> - if (copy_pud(dst_pgdp, src_pgdp, addr, next))
> + if (copy_p4d(dst_pgdp, src_pgdp, addr, next))
> return -ENOMEM;
> } while (dst_pgdp++, src_pgdp++, addr = next, addr != end);
>
> --- a/arch/arm64/kvm/mmu.c~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/kvm/mmu.c
> @@ -158,13 +158,22 @@ static void *mmu_memory_cache_alloc(stru
>
> static void clear_stage2_pgd_entry(struct kvm *kvm, pgd_t *pgd, phys_addr_t addr)
> {
> - pud_t *pud_table __maybe_unused = stage2_pud_offset(kvm, pgd, 0UL);
> + p4d_t *p4d_table __maybe_unused = stage2_p4d_offset(kvm, pgd, 0UL);
> stage2_pgd_clear(kvm, pgd);
> kvm_tlb_flush_vmid_ipa(kvm, addr);
> - stage2_pud_free(kvm, pud_table);
> + stage2_p4d_free(kvm, p4d_table);
> put_page(virt_to_page(pgd));
> }
>
> +static void clear_stage2_p4d_entry(struct kvm *kvm, p4d_t *p4d, phys_addr_t addr)
> +{
> + pud_t *pud_table __maybe_unused = stage2_pud_offset(kvm, p4d, 0);
> + stage2_p4d_clear(kvm, p4d);
> + kvm_tlb_flush_vmid_ipa(kvm, addr);
> + stage2_pud_free(kvm, pud_table);
> + put_page(virt_to_page(p4d));
> +}
> +
> static void clear_stage2_pud_entry(struct kvm *kvm, pud_t *pud, phys_addr_t addr)
> {
> pmd_t *pmd_table __maybe_unused = stage2_pmd_offset(kvm, pud, 0);
> @@ -208,12 +217,20 @@ static inline void kvm_pud_populate(pud_
> dsb(ishst);
> }
>
> -static inline void kvm_pgd_populate(pgd_t *pgdp, pud_t *pudp)
> +static inline void kvm_p4d_populate(p4d_t *p4dp, pud_t *pudp)
> {
> - WRITE_ONCE(*pgdp, kvm_mk_pgd(pudp));
> + WRITE_ONCE(*p4dp, kvm_mk_p4d(pudp));
> dsb(ishst);
> }
>
> +static inline void kvm_pgd_populate(pgd_t *pgdp, p4d_t *p4dp)
> +{
> +#ifndef __PAGETABLE_P4D_FOLDED
> + WRITE_ONCE(*pgdp, kvm_mk_pgd(p4dp));
> + dsb(ishst);
> +#endif
> +}
> +
> /*
> * Unmapping vs dcache management:
> *
> @@ -293,13 +310,13 @@ static void unmap_stage2_pmds(struct kvm
> clear_stage2_pud_entry(kvm, pud, start_addr);
> }
>
> -static void unmap_stage2_puds(struct kvm *kvm, pgd_t *pgd,
> +static void unmap_stage2_puds(struct kvm *kvm, p4d_t *p4d,
> phys_addr_t addr, phys_addr_t end)
> {
> phys_addr_t next, start_addr = addr;
> pud_t *pud, *start_pud;
>
> - start_pud = pud = stage2_pud_offset(kvm, pgd, addr);
> + start_pud = pud = stage2_pud_offset(kvm, p4d, addr);
> do {
> next = stage2_pud_addr_end(kvm, addr, end);
> if (!stage2_pud_none(kvm, *pud)) {
> @@ -317,6 +334,23 @@ static void unmap_stage2_puds(struct kvm
> } while (pud++, addr = next, addr != end);
>
> if (stage2_pud_table_empty(kvm, start_pud))
> + clear_stage2_p4d_entry(kvm, p4d, start_addr);
> +}
> +
> +static void unmap_stage2_p4ds(struct kvm *kvm, pgd_t *pgd,
> + phys_addr_t addr, phys_addr_t end)
> +{
> + phys_addr_t next, start_addr = addr;
> + p4d_t *p4d, *start_p4d;
> +
> + start_p4d = p4d = stage2_p4d_offset(kvm, pgd, addr);
> + do {
> + next = stage2_p4d_addr_end(kvm, addr, end);
> + if (!stage2_p4d_none(kvm, *p4d))
> + unmap_stage2_puds(kvm, p4d, addr, next);
> + } while (p4d++, addr = next, addr != end);
> +
> + if (stage2_p4d_table_empty(kvm, start_p4d))
> clear_stage2_pgd_entry(kvm, pgd, start_addr);
> }
>
> @@ -351,7 +385,7 @@ static void unmap_stage2_range(struct kv
> break;
> next = stage2_pgd_addr_end(kvm, addr, end);
> if (!stage2_pgd_none(kvm, *pgd))
> - unmap_stage2_puds(kvm, pgd, addr, next);
> + unmap_stage2_p4ds(kvm, pgd, addr, next);
> /*
> * If the range is too large, release the kvm->mmu_lock
> * to prevent starvation and lockup detector warnings.
> @@ -391,13 +425,13 @@ static void stage2_flush_pmds(struct kvm
> } while (pmd++, addr = next, addr != end);
> }
>
> -static void stage2_flush_puds(struct kvm *kvm, pgd_t *pgd,
> +static void stage2_flush_puds(struct kvm *kvm, p4d_t *p4d,
> phys_addr_t addr, phys_addr_t end)
> {
> pud_t *pud;
> phys_addr_t next;
>
> - pud = stage2_pud_offset(kvm, pgd, addr);
> + pud = stage2_pud_offset(kvm, p4d, addr);
> do {
> next = stage2_pud_addr_end(kvm, addr, end);
> if (!stage2_pud_none(kvm, *pud)) {
> @@ -409,6 +443,20 @@ static void stage2_flush_puds(struct kvm
> } while (pud++, addr = next, addr != end);
> }
>
> +static void stage2_flush_p4ds(struct kvm *kvm, pgd_t *pgd,
> + phys_addr_t addr, phys_addr_t end)
> +{
> + p4d_t *p4d;
> + phys_addr_t next;
> +
> + p4d = stage2_p4d_offset(kvm, pgd, addr);
> + do {
> + next = stage2_p4d_addr_end(kvm, addr, end);
> + if (!stage2_p4d_none(kvm, *p4d))
> + stage2_flush_puds(kvm, p4d, addr, next);
> + } while (p4d++, addr = next, addr != end);
> +}
> +
> static void stage2_flush_memslot(struct kvm *kvm,
> struct kvm_memory_slot *memslot)
> {
> @@ -421,7 +469,7 @@ static void stage2_flush_memslot(struct
> do {
> next = stage2_pgd_addr_end(kvm, addr, end);
> if (!stage2_pgd_none(kvm, *pgd))
> - stage2_flush_puds(kvm, pgd, addr, next);
> + stage2_flush_p4ds(kvm, pgd, addr, next);
>
> if (next != end)
> cond_resched_lock(&kvm->mmu_lock);
> @@ -454,12 +502,21 @@ static void stage2_flush_vm(struct kvm *
>
> static void clear_hyp_pgd_entry(pgd_t *pgd)
> {
> - pud_t *pud_table __maybe_unused = pud_offset(pgd, 0UL);
> + p4d_t *p4d_table __maybe_unused = p4d_offset(pgd, 0UL);
> pgd_clear(pgd);
> - pud_free(NULL, pud_table);
> + p4d_free(NULL, p4d_table);
> put_page(virt_to_page(pgd));
> }
>
> +static void clear_hyp_p4d_entry(p4d_t *p4d)
> +{
> + pud_t *pud_table __maybe_unused = pud_offset(p4d, 0);
> + VM_BUG_ON(p4d_huge(*p4d));
> + p4d_clear(p4d);
> + pud_free(NULL, pud_table);
> + put_page(virt_to_page(p4d));
> +}
> +
> static void clear_hyp_pud_entry(pud_t *pud)
> {
> pmd_t *pmd_table __maybe_unused = pmd_offset(pud, 0);
> @@ -511,12 +568,12 @@ static void unmap_hyp_pmds(pud_t *pud, p
> clear_hyp_pud_entry(pud);
> }
>
> -static void unmap_hyp_puds(pgd_t *pgd, phys_addr_t addr, phys_addr_t end)
> +static void unmap_hyp_puds(p4d_t *p4d, phys_addr_t addr, phys_addr_t end)
> {
> phys_addr_t next;
> pud_t *pud, *start_pud;
>
> - start_pud = pud = pud_offset(pgd, addr);
> + start_pud = pud = pud_offset(p4d, addr);
> do {
> next = pud_addr_end(addr, end);
> /* Hyp doesn't use huge puds */
> @@ -525,6 +582,23 @@ static void unmap_hyp_puds(pgd_t *pgd, p
> } while (pud++, addr = next, addr != end);
>
> if (hyp_pud_table_empty(start_pud))
> + clear_hyp_p4d_entry(p4d);
> +}
> +
> +static void unmap_hyp_p4ds(pgd_t *pgd, phys_addr_t addr, phys_addr_t end)
> +{
> + phys_addr_t next;
> + p4d_t *p4d, *start_p4d;
> +
> + start_p4d = p4d = p4d_offset(pgd, addr);
> + do {
> + next = p4d_addr_end(addr, end);
> + /* Hyp doesn't use huge p4ds */
> + if (!p4d_none(*p4d))
> + unmap_hyp_puds(p4d, addr, next);
> + } while (p4d++, addr = next, addr != end);
> +
> + if (hyp_p4d_table_empty(start_p4d))
> clear_hyp_pgd_entry(pgd);
> }
>
> @@ -548,7 +622,7 @@ static void __unmap_hyp_range(pgd_t *pgd
> do {
> next = pgd_addr_end(addr, end);
> if (!pgd_none(*pgd))
> - unmap_hyp_puds(pgd, addr, next);
> + unmap_hyp_p4ds(pgd, addr, next);
> } while (pgd++, addr = next, addr != end);
> }
>
> @@ -658,7 +732,7 @@ static int create_hyp_pmd_mappings(pud_t
> return 0;
> }
>
> -static int create_hyp_pud_mappings(pgd_t *pgd, unsigned long start,
> +static int create_hyp_pud_mappings(p4d_t *p4d, unsigned long start,
> unsigned long end, unsigned long pfn,
> pgprot_t prot)
> {
> @@ -669,7 +743,7 @@ static int create_hyp_pud_mappings(pgd_t
>
> addr = start;
> do {
> - pud = pud_offset(pgd, addr);
> + pud = pud_offset(p4d, addr);
>
> if (pud_none_or_clear_bad(pud)) {
> pmd = pmd_alloc_one(NULL, addr);
> @@ -691,12 +765,45 @@ static int create_hyp_pud_mappings(pgd_t
> return 0;
> }
>
> +static int create_hyp_p4d_mappings(pgd_t *pgd, unsigned long start,
> + unsigned long end, unsigned long pfn,
> + pgprot_t prot)
> +{
> + p4d_t *p4d;
> + pud_t *pud;
> + unsigned long addr, next;
> + int ret;
> +
> + addr = start;
> + do {
> + p4d = p4d_offset(pgd, addr);
> +
> + if (p4d_none(*p4d)) {
> + pud = pud_alloc_one(NULL, addr);
> + if (!pud) {
> + kvm_err("Cannot allocate Hyp pud\n");
> + return -ENOMEM;
> + }
> + kvm_p4d_populate(p4d, pud);
> + get_page(virt_to_page(p4d));
> + }
> +
> + next = p4d_addr_end(addr, end);
> + ret = create_hyp_pud_mappings(p4d, addr, next, pfn, prot);
> + if (ret)
> + return ret;
> + pfn += (next - addr) >> PAGE_SHIFT;
> + } while (addr = next, addr != end);
> +
> + return 0;
> +}
> +
> static int __create_hyp_mappings(pgd_t *pgdp, unsigned long ptrs_per_pgd,
> unsigned long start, unsigned long end,
> unsigned long pfn, pgprot_t prot)
> {
> pgd_t *pgd;
> - pud_t *pud;
> + p4d_t *p4d;
> unsigned long addr, next;
> int err = 0;
>
> @@ -707,18 +814,18 @@ static int __create_hyp_mappings(pgd_t *
> pgd = pgdp + kvm_pgd_index(addr, ptrs_per_pgd);
>
> if (pgd_none(*pgd)) {
> - pud = pud_alloc_one(NULL, addr);
> - if (!pud) {
> - kvm_err("Cannot allocate Hyp pud\n");
> + p4d = p4d_alloc_one(NULL, addr);
> + if (!p4d) {
> + kvm_err("Cannot allocate Hyp p4d\n");
> err = -ENOMEM;
> goto out;
> }
> - kvm_pgd_populate(pgd, pud);
> + kvm_pgd_populate(pgd, p4d);
> get_page(virt_to_page(pgd));
> }
>
> next = pgd_addr_end(addr, end);
> - err = create_hyp_pud_mappings(pgd, addr, next, pfn, prot);
> + err = create_hyp_p4d_mappings(pgd, addr, next, pfn, prot);
> if (err)
> goto out;
> pfn += (next - addr) >> PAGE_SHIFT;
> @@ -1015,22 +1122,40 @@ void kvm_free_stage2_pgd(struct kvm *kvm
> free_pages_exact(pgd, stage2_pgd_size(kvm));
> }
>
> -static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
> +static p4d_t *stage2_get_p4d(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
> phys_addr_t addr)
> {
> pgd_t *pgd;
> - pud_t *pud;
> + p4d_t *p4d;
>
> pgd = kvm->arch.pgd + stage2_pgd_index(kvm, addr);
> if (stage2_pgd_none(kvm, *pgd)) {
> if (!cache)
> return NULL;
> - pud = mmu_memory_cache_alloc(cache);
> - stage2_pgd_populate(kvm, pgd, pud);
> + p4d = mmu_memory_cache_alloc(cache);
> + stage2_pgd_populate(kvm, pgd, p4d);
> get_page(virt_to_page(pgd));
> }
>
> - return stage2_pud_offset(kvm, pgd, addr);
> + return stage2_p4d_offset(kvm, pgd, addr);
> +}
> +
> +static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
> + phys_addr_t addr)
> +{
> + p4d_t *p4d;
> + pud_t *pud;
> +
> + p4d = stage2_get_p4d(kvm, cache, addr);
> + if (stage2_p4d_none(kvm, *p4d)) {
> + if (!cache)
> + return NULL;
> + pud = mmu_memory_cache_alloc(cache);
> + stage2_p4d_populate(kvm, p4d, pud);
> + get_page(virt_to_page(p4d));
> + }
> +
> + return stage2_pud_offset(kvm, p4d, addr);
> }
>
> static pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
> @@ -1423,18 +1548,18 @@ static void stage2_wp_pmds(struct kvm *k
> }
>
> /**
> - * stage2_wp_puds - write protect PGD range
> + * stage2_wp_puds - write protect P4D range
> * @pgd: pointer to pgd entry
> * @addr: range start address
> * @end: range end address
> */
> -static void stage2_wp_puds(struct kvm *kvm, pgd_t *pgd,
> +static void stage2_wp_puds(struct kvm *kvm, p4d_t *p4d,
> phys_addr_t addr, phys_addr_t end)
> {
> pud_t *pud;
> phys_addr_t next;
>
> - pud = stage2_pud_offset(kvm, pgd, addr);
> + pud = stage2_pud_offset(kvm, p4d, addr);
> do {
> next = stage2_pud_addr_end(kvm, addr, end);
> if (!stage2_pud_none(kvm, *pud)) {
> @@ -1449,6 +1574,26 @@ static void stage2_wp_puds(struct kvm *
> }
>
> /**
> + * stage2_wp_p4ds - write protect PGD range
> + * @pgd: pointer to pgd entry
> + * @addr: range start address
> + * @end: range end address
> + */
> +static void stage2_wp_p4ds(struct kvm *kvm, pgd_t *pgd,
> + phys_addr_t addr, phys_addr_t end)
> +{
> + p4d_t *p4d;
> + phys_addr_t next;
> +
> + p4d = stage2_p4d_offset(kvm, pgd, addr);
> + do {
> + next = stage2_p4d_addr_end(kvm, addr, end);
> + if (!stage2_p4d_none(kvm, *p4d))
> + stage2_wp_puds(kvm, p4d, addr, next);
> + } while (p4d++, addr = next, addr != end);
> +}
> +
> +/**
> * stage2_wp_range() - write protect stage2 memory region range
> * @kvm: The KVM pointer
> * @addr: Start address of range
> @@ -1475,7 +1620,7 @@ static void stage2_wp_range(struct kvm *
> break;
> next = stage2_pgd_addr_end(kvm, addr, end);
> if (stage2_pgd_present(kvm, *pgd))
> - stage2_wp_puds(kvm, pgd, addr, next);
> + stage2_wp_p4ds(kvm, pgd, addr, next);
> } while (pgd++, addr = next, addr != end);
> }
>
> --- a/arch/arm64/mm/fault.c~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/mm/fault.c
> @@ -145,6 +145,7 @@ static void show_pte(unsigned long addr)
> pr_alert("[%016lx] pgd=%016llx", addr, pgd_val(pgd));
>
> do {
> + p4d_t *p4dp, p4d;
> pud_t *pudp, pud;
> pmd_t *pmdp, pmd;
> pte_t *ptep, pte;
> @@ -152,7 +153,13 @@ static void show_pte(unsigned long addr)
> if (pgd_none(pgd) || pgd_bad(pgd))
> break;
>
> - pudp = pud_offset(pgdp, addr);
> + p4dp = p4d_offset(pgdp, addr);
> + p4d = READ_ONCE(*p4dp);
> + pr_cont(", p4d=%016llx", p4d_val(p4d));
> + if (p4d_none(p4d) || p4d_bad(p4d))
> + break;
> +
> + pudp = pud_offset(p4dp, addr);
> pud = READ_ONCE(*pudp);
> pr_cont(", pud=%016llx", pud_val(pud));
> if (pud_none(pud) || pud_bad(pud))
> --- a/arch/arm64/mm/hugetlbpage.c~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/mm/hugetlbpage.c
> @@ -67,11 +67,13 @@ static int find_num_contig(struct mm_str
> pte_t *ptep, size_t *pgsize)
> {
> pgd_t *pgdp = pgd_offset(mm, addr);
> + p4d_t *p4dp;
> pud_t *pudp;
> pmd_t *pmdp;
>
> *pgsize = PAGE_SIZE;
> - pudp = pud_offset(pgdp, addr);
> + p4dp = p4d_offset(pgdp, addr);
> + pudp = pud_offset(p4dp, addr);
> pmdp = pmd_offset(pudp, addr);
> if ((pte_t *)pmdp == ptep) {
> *pgsize = PMD_SIZE;
> @@ -217,12 +219,14 @@ pte_t *huge_pte_alloc(struct mm_struct *
> unsigned long addr, unsigned long sz)
> {
> pgd_t *pgdp;
> + p4d_t *p4dp;
> pud_t *pudp;
> pmd_t *pmdp;
> pte_t *ptep = NULL;
>
> pgdp = pgd_offset(mm, addr);
> - pudp = pud_alloc(mm, pgdp, addr);
> + p4dp = p4d_offset(pgdp, addr);
> + pudp = pud_alloc(mm, p4dp, addr);
> if (!pudp)
> return NULL;
>
> @@ -261,6 +265,7 @@ pte_t *huge_pte_offset(struct mm_struct
> unsigned long addr, unsigned long sz)
> {
> pgd_t *pgdp;
> + p4d_t *p4dp;
> pud_t *pudp, pud;
> pmd_t *pmdp, pmd;
>
> @@ -268,7 +273,11 @@ pte_t *huge_pte_offset(struct mm_struct
> if (!pgd_present(READ_ONCE(*pgdp)))
> return NULL;
>
> - pudp = pud_offset(pgdp, addr);
> + p4dp = p4d_offset(pgdp, addr);
> + if (!p4d_present(READ_ONCE(*p4dp)))
> + return NULL;
> +
> + pudp = pud_offset(p4dp, addr);
> pud = READ_ONCE(*pudp);
> if (sz != PUD_SIZE && pud_none(pud))
> return NULL;
> --- a/arch/arm64/mm/kasan_init.c~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/mm/kasan_init.c
> @@ -84,17 +84,17 @@ static pmd_t *__init kasan_pmd_offset(pu
> return early ? pmd_offset_kimg(pudp, addr) : pmd_offset(pudp, addr);
> }
>
> -static pud_t *__init kasan_pud_offset(pgd_t *pgdp, unsigned long addr, int node,
> +static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node,
> bool early)
> {
> - if (pgd_none(READ_ONCE(*pgdp))) {
> + if (p4d_none(READ_ONCE(*p4dp))) {
> phys_addr_t pud_phys = early ?
> __pa_symbol(kasan_early_shadow_pud)
> : kasan_alloc_zeroed_page(node);
> - __pgd_populate(pgdp, pud_phys, PMD_TYPE_TABLE);
> + __p4d_populate(p4dp, pud_phys, PMD_TYPE_TABLE);
> }
>
> - return early ? pud_offset_kimg(pgdp, addr) : pud_offset(pgdp, addr);
> + return early ? pud_offset_kimg(p4dp, addr) : pud_offset(p4dp, addr);
> }
>
> static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
> @@ -126,11 +126,11 @@ static void __init kasan_pmd_populate(pu
> } while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp)));
> }
>
> -static void __init kasan_pud_populate(pgd_t *pgdp, unsigned long addr,
> +static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
> unsigned long end, int node, bool early)
> {
> unsigned long next;
> - pud_t *pudp = kasan_pud_offset(pgdp, addr, node, early);
> + pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);
>
> do {
> next = pud_addr_end(addr, end);
> @@ -138,6 +138,18 @@ static void __init kasan_pud_populate(pg
> } while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp)));
> }
>
> +static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
> + unsigned long end, int node, bool early)
> +{
> + unsigned long next;
> + p4d_t *p4dp = p4d_offset(pgdp, addr);
> +
> + do {
> + next = p4d_addr_end(addr, end);
> + kasan_pud_populate(p4dp, addr, next, node, early);
> + } while (p4dp++, addr = next, addr != end);
> +}
> +
> static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
> int node, bool early)
> {
> @@ -147,7 +159,7 @@ static void __init kasan_pgd_populate(un
> pgdp = pgd_offset_k(addr);
> do {
> next = pgd_addr_end(addr, end);
> - kasan_pud_populate(pgdp, addr, next, node, early);
> + kasan_p4d_populate(pgdp, addr, next, node, early);
> } while (pgdp++, addr = next, addr != end);
> }
>
> --- a/arch/arm64/mm/mmu.c~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/mm/mmu.c
> @@ -290,18 +290,19 @@ static void alloc_init_pud(pgd_t *pgdp,
> {
> unsigned long next;
> pud_t *pudp;
> - pgd_t pgd = READ_ONCE(*pgdp);
> + p4d_t *p4dp = p4d_offset(pgdp, addr);
> + p4d_t p4d = READ_ONCE(*p4dp);
>
> - if (pgd_none(pgd)) {
> + if (p4d_none(p4d)) {
> phys_addr_t pud_phys;
> BUG_ON(!pgtable_alloc);
> pud_phys = pgtable_alloc(PUD_SHIFT);
> - __pgd_populate(pgdp, pud_phys, PUD_TYPE_TABLE);
> - pgd = READ_ONCE(*pgdp);
> + __p4d_populate(p4dp, pud_phys, PUD_TYPE_TABLE);
> + p4d = READ_ONCE(*p4dp);
> }
> - BUG_ON(pgd_bad(pgd));
> + BUG_ON(p4d_bad(p4d));
>
> - pudp = pud_set_fixmap_offset(pgdp, addr);
> + pudp = pud_set_fixmap_offset(p4dp, addr);
> do {
> pud_t old_pud = READ_ONCE(*pudp);
>
> @@ -672,6 +673,7 @@ static void __init map_kernel(pgd_t *pgd
> READ_ONCE(*pgd_offset_k(FIXADDR_START)));
> } else if (CONFIG_PGTABLE_LEVELS > 3) {
> pgd_t *bm_pgdp;
> + p4d_t *bm_p4dp;
> pud_t *bm_pudp;
> /*
> * The fixmap shares its top level pgd entry with the kernel
> @@ -681,7 +683,8 @@ static void __init map_kernel(pgd_t *pgd
> */
> BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
> bm_pgdp = pgd_offset_raw(pgdp, FIXADDR_START);
> - bm_pudp = pud_set_fixmap_offset(bm_pgdp, FIXADDR_START);
> + bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START);
> + bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START);
> pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd));
> pud_clear_fixmap();
> } else {
> @@ -715,6 +718,7 @@ void __init paging_init(void)
> int kern_addr_valid(unsigned long addr)
> {
> pgd_t *pgdp;
> + p4d_t *p4dp;
> pud_t *pudp, pud;
> pmd_t *pmdp, pmd;
> pte_t *ptep, pte;
> @@ -726,7 +730,11 @@ int kern_addr_valid(unsigned long addr)
> if (pgd_none(READ_ONCE(*pgdp)))
> return 0;
>
> - pudp = pud_offset(pgdp, addr);
> + p4dp = p4d_offset(pgdp, addr);
> + if (p4d_none(READ_ONCE(*p4dp)))
> + return 0;
> +
> + pudp = pud_offset(p4dp, addr);
> pud = READ_ONCE(*pudp);
> if (pud_none(pud))
> return 0;
> @@ -1069,6 +1077,7 @@ int __meminit vmemmap_populate(unsigned
> unsigned long addr = start;
> unsigned long next;
> pgd_t *pgdp;
> + p4d_t *p4dp;
> pud_t *pudp;
> pmd_t *pmdp;
>
> @@ -1079,7 +1088,11 @@ int __meminit vmemmap_populate(unsigned
> if (!pgdp)
> return -ENOMEM;
>
> - pudp = vmemmap_pud_populate(pgdp, addr, node);
> + p4dp = vmemmap_p4d_populate(pgdp, addr, node);
> + if (!p4dp)
> + return -ENOMEM;
> +
> + pudp = vmemmap_pud_populate(p4dp, addr, node);
> if (!pudp)
> return -ENOMEM;
>
> @@ -1114,11 +1127,12 @@ void vmemmap_free(unsigned long start, u
> static inline pud_t * fixmap_pud(unsigned long addr)
> {
> pgd_t *pgdp = pgd_offset_k(addr);
> - pgd_t pgd = READ_ONCE(*pgdp);
> + p4d_t *p4dp = p4d_offset(pgdp, addr);
> + p4d_t p4d = READ_ONCE(*p4dp);
>
> - BUG_ON(pgd_none(pgd) || pgd_bad(pgd));
> + BUG_ON(p4d_none(p4d) || p4d_bad(p4d));
>
> - return pud_offset_kimg(pgdp, addr);
> + return pud_offset_kimg(p4dp, addr);
> }
>
> static inline pmd_t * fixmap_pmd(unsigned long addr)
> @@ -1144,25 +1158,27 @@ static inline pte_t * fixmap_pte(unsigne
> */
> void __init early_fixmap_init(void)
> {
> - pgd_t *pgdp, pgd;
> + pgd_t *pgdp;
> + p4d_t *p4dp, p4d;
> pud_t *pudp;
> pmd_t *pmdp;
> unsigned long addr = FIXADDR_START;
>
> pgdp = pgd_offset_k(addr);
> - pgd = READ_ONCE(*pgdp);
> + p4dp = p4d_offset(pgdp, addr);
> + p4d = READ_ONCE(*p4dp);
> if (CONFIG_PGTABLE_LEVELS > 3 &&
> - !(pgd_none(pgd) || pgd_page_paddr(pgd) == __pa_symbol(bm_pud))) {
> + !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) {
> /*
> * We only end up here if the kernel mapping and the fixmap
> * share the top level pgd entry, which should only happen on
> * 16k/4 levels configurations.
> */
> BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
> - pudp = pud_offset_kimg(pgdp, addr);
> + pudp = pud_offset_kimg(p4dp, addr);
> } else {
> - if (pgd_none(pgd))
> - __pgd_populate(pgdp, __pa_symbol(bm_pud), PUD_TYPE_TABLE);
> + if (p4d_none(p4d))
> + __p4d_populate(p4dp, __pa_symbol(bm_pud), PUD_TYPE_TABLE);
> pudp = fixmap_pud(addr);
> }
> if (pud_none(READ_ONCE(*pudp)))
> --- a/arch/arm64/mm/pageattr.c~arm64-add-support-for-folded-p4d-page-tables
> +++ a/arch/arm64/mm/pageattr.c
> @@ -198,6 +198,7 @@ void __kernel_map_pages(struct page *pag
> bool kernel_page_present(struct page *page)
> {
> pgd_t *pgdp;
> + p4d_t *p4dp;
> pud_t *pudp, pud;
> pmd_t *pmdp, pmd;
> pte_t *ptep;
> @@ -210,7 +211,11 @@ bool kernel_page_present(struct page *pa
> if (pgd_none(READ_ONCE(*pgdp)))
> return false;
>
> - pudp = pud_offset(pgdp, addr);
> + p4dp = p4d_offset(pgdp, addr);
> + if (p4d_none(READ_ONCE(*p4dp)))
> + return false;
> +
> + pudp = pud_offset(p4dp, addr);
> pud = READ_ONCE(*pudp);
> if (pud_none(pud))
> return false;
> _
>
--
Sincerely yours,
Mike.