From 44382b0195e608732b0bed14d51b5e5f79f46471 Mon Sep 17 00:00:00 2001 From: Nitin Gupta Date: Fri, 11 Aug 2017 16:46:49 -0700 Subject: [PATCH 1/3] sparc64: Support huge PUD case in get_user_pages get_user_pages() is used to do direct IO. It already handles the case where the address range is backed by PMD huge pages. This patch now adds the case where the range could be backed by PUD huge pages. Signed-off-by: Nitin Gupta Signed-off-by: David S. Miller --- arch/sparc/include/asm/pgtable_64.h | 15 ++++++++-- arch/sparc/mm/gup.c | 45 ++++++++++++++++++++++++++++- 2 files changed, 57 insertions(+), 3 deletions(-) diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h index 6fbd931f0570..2579f5a22f46 100644 --- a/arch/sparc/include/asm/pgtable_64.h +++ b/arch/sparc/include/asm/pgtable_64.h @@ -687,6 +687,8 @@ static inline unsigned long pmd_write(pmd_t pmd) return pte_write(pte); } +#define pud_write(pud) pte_write(__pte(pud_val(pud))) + #ifdef CONFIG_TRANSPARENT_HUGEPAGE static inline unsigned long pmd_dirty(pmd_t pmd) { @@ -823,9 +825,18 @@ static inline unsigned long __pmd_page(pmd_t pmd) return ((unsigned long) __va(pfn << PAGE_SHIFT)); } + +static inline unsigned long pud_page_vaddr(pud_t pud) +{ + pte_t pte = __pte(pud_val(pud)); + unsigned long pfn; + + pfn = pte_pfn(pte); + + return ((unsigned long) __va(pfn << PAGE_SHIFT)); +} + #define pmd_page(pmd) virt_to_page((void *)__pmd_page(pmd)) -#define pud_page_vaddr(pud) \ - ((unsigned long) __va(pud_val(pud))) #define pud_page(pud) virt_to_page((void *)pud_page_vaddr(pud)) #define pmd_clear(pmdp) (pmd_val(*(pmdp)) = 0UL) #define pud_present(pud) (pud_val(pud) != 0U) diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c index f80cfc64c55b..d809099ffd47 100644 --- a/arch/sparc/mm/gup.c +++ b/arch/sparc/mm/gup.c @@ -103,6 +103,45 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr, return 1; } +static int gup_huge_pud(pud_t *pudp, pud_t pud, unsigned long addr, + unsigned long end, int write, struct page **pages, + int *nr) +{ + struct page *head, *page; + int refs; + + if (!(pud_val(pud) & _PAGE_VALID)) + return 0; + + if (write && !pud_write(pud)) + return 0; + + refs = 0; + page = pud_page(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); + head = compound_head(page); + do { + VM_BUG_ON(compound_head(page) != head); + pages[*nr] = page; + (*nr)++; + page++; + refs++; + } while (addr += PAGE_SIZE, addr != end); + + if (!page_cache_add_speculative(head, refs)) { + *nr -= refs; + return 0; + } + + if (unlikely(pud_val(pud) != pud_val(*pudp))) { + *nr -= refs; + while (refs--) + put_page(head); + return 0; + } + + return 1; +} + static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { @@ -141,7 +180,11 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, next = pud_addr_end(addr, end); if (pud_none(pud)) return 0; - if (!gup_pmd_range(pud, addr, next, write, pages, nr)) + if (unlikely(pud_large(pud))) { + if (!gup_huge_pud(pudp, pud, addr, next, + write, pages, nr)) + return 0; + } else if (!gup_pmd_range(pud, addr, next, write, pages, nr)) return 0; } while (pudp++, addr = next, addr != end); From df7b2155bbe75525531e47c8a67ae4f1dbbae976 Mon Sep 17 00:00:00 2001 From: Nitin Gupta Date: Fri, 11 Aug 2017 16:46:50 -0700 Subject: [PATCH 2/3] sparc64: Add 16GB hugepage support Adds support for 16GB hugepage size. To use this page size use kernel parameters as: default_hugepagesz=16G hugepagesz=16G hugepages=10 Testing: Tested with the stream benchmark which allocates 48G of arrays backed by 16G hugepages and does RW operation on them in parallel. Orabug: 25362942 Cc: Anthony Yznaga Reviewed-by: Bob Picco Signed-off-by: Nitin Gupta Signed-off-by: David S. Miller --- arch/sparc/include/asm/hugetlb.h | 7 +++ arch/sparc/include/asm/page_64.h | 3 +- arch/sparc/include/asm/pgtable_64.h | 5 ++ arch/sparc/include/asm/tsb.h | 36 ++++++++++++++ arch/sparc/kernel/head_64.S | 2 +- arch/sparc/kernel/tsb.S | 2 +- arch/sparc/kernel/vmlinux.lds.S | 5 ++ arch/sparc/mm/hugetlbpage.c | 76 ++++++++++++++++++++--------- arch/sparc/mm/init_64.c | 54 +++++++++++++++++--- 9 files changed, 158 insertions(+), 32 deletions(-) diff --git a/arch/sparc/include/asm/hugetlb.h b/arch/sparc/include/asm/hugetlb.h index d1f837dc77a4..0ca7caab1b06 100644 --- a/arch/sparc/include/asm/hugetlb.h +++ b/arch/sparc/include/asm/hugetlb.h @@ -4,6 +4,13 @@ #include #include +#ifdef CONFIG_HUGETLB_PAGE +struct pud_huge_patch_entry { + unsigned int addr; + unsigned int insn; +}; +extern struct pud_huge_patch_entry __pud_huge_patch, __pud_huge_patch_end; +#endif void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte); diff --git a/arch/sparc/include/asm/page_64.h b/arch/sparc/include/asm/page_64.h index 5961b2d8398a..8ee1f97589a1 100644 --- a/arch/sparc/include/asm/page_64.h +++ b/arch/sparc/include/asm/page_64.h @@ -17,6 +17,7 @@ #define HPAGE_SHIFT 23 #define REAL_HPAGE_SHIFT 22 +#define HPAGE_16GB_SHIFT 34 #define HPAGE_2GB_SHIFT 31 #define HPAGE_256MB_SHIFT 28 #define HPAGE_64K_SHIFT 16 @@ -28,7 +29,7 @@ #define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT) #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA #define REAL_HPAGE_PER_HPAGE (_AC(1,UL) << (HPAGE_SHIFT - REAL_HPAGE_SHIFT)) -#define HUGE_MAX_HSTATE 4 +#define HUGE_MAX_HSTATE 5 #endif #ifndef __ASSEMBLY__ diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h index 2579f5a22f46..4fefe3762083 100644 --- a/arch/sparc/include/asm/pgtable_64.h +++ b/arch/sparc/include/asm/pgtable_64.h @@ -414,6 +414,11 @@ static inline bool is_hugetlb_pmd(pmd_t pmd) return !!(pmd_val(pmd) & _PAGE_PMD_HUGE); } +static inline bool is_hugetlb_pud(pud_t pud) +{ + return !!(pud_val(pud) & _PAGE_PUD_HUGE); +} + #ifdef CONFIG_TRANSPARENT_HUGEPAGE static inline pmd_t pmd_mkhuge(pmd_t pmd) { diff --git a/arch/sparc/include/asm/tsb.h b/arch/sparc/include/asm/tsb.h index 32258e08da03..acf55063aa3d 100644 --- a/arch/sparc/include/asm/tsb.h +++ b/arch/sparc/include/asm/tsb.h @@ -195,6 +195,41 @@ extern struct tsb_phys_patch_entry __tsb_phys_patch, __tsb_phys_patch_end; nop; \ 699: + /* PUD has been loaded into REG1, interpret the value, seeing + * if it is a HUGE PUD or a normal one. If it is not valid + * then jump to FAIL_LABEL. If it is a HUGE PUD, and it + * translates to a valid PTE, branch to PTE_LABEL. + * + * We have to propagate bits [32:22] from the virtual address + * to resolve at 4M granularity. + */ +#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) +#define USER_PGTABLE_CHECK_PUD_HUGE(VADDR, REG1, REG2, FAIL_LABEL, PTE_LABEL) \ +700: ba 700f; \ + nop; \ + .section .pud_huge_patch, "ax"; \ + .word 700b; \ + nop; \ + .previous; \ + brz,pn REG1, FAIL_LABEL; \ + sethi %uhi(_PAGE_PUD_HUGE), REG2; \ + sllx REG2, 32, REG2; \ + andcc REG1, REG2, %g0; \ + be,pt %xcc, 700f; \ + sethi %hi(0x1ffc0000), REG2; \ + sllx REG2, 1, REG2; \ + brgez,pn REG1, FAIL_LABEL; \ + andn REG1, REG2, REG1; \ + and VADDR, REG2, REG2; \ + brlz,pt REG1, PTE_LABEL; \ + or REG1, REG2, REG1; \ +700: +#else +#define USER_PGTABLE_CHECK_PUD_HUGE(VADDR, REG1, REG2, FAIL_LABEL, PTE_LABEL) \ + brz,pn REG1, FAIL_LABEL; \ + nop; +#endif + /* PMD has been loaded into REG1, interpret the value, seeing * if it is a HUGE PMD or a normal one. If it is not valid * then jump to FAIL_LABEL. If it is a HUGE PMD, and it @@ -242,6 +277,7 @@ extern struct tsb_phys_patch_entry __tsb_phys_patch, __tsb_phys_patch_end; srlx REG2, 64 - PAGE_SHIFT, REG2; \ andn REG2, 0x7, REG2; \ ldxa [REG1 + REG2] ASI_PHYS_USE_EC, REG1; \ + USER_PGTABLE_CHECK_PUD_HUGE(VADDR, REG1, REG2, FAIL_LABEL, 800f) \ brz,pn REG1, FAIL_LABEL; \ sllx VADDR, 64 - (PMD_SHIFT + PMD_BITS), REG2; \ srlx REG2, 64 - PAGE_SHIFT, REG2; \ diff --git a/arch/sparc/kernel/head_64.S b/arch/sparc/kernel/head_64.S index bf9a5acc8432..4de9fbd1a177 100644 --- a/arch/sparc/kernel/head_64.S +++ b/arch/sparc/kernel/head_64.S @@ -893,7 +893,6 @@ sparc64_boot_end: #include "misctrap.S" #include "syscalls.S" #include "helpers.S" -#include "hvcalls.S" #include "sun4v_tlb_miss.S" #include "sun4v_ivec.S" #include "ktlb.S" @@ -938,6 +937,7 @@ swapper_4m_tsb: ! 0x0000000000428000 +#include "hvcalls.S" #include "systbls_64.S" .data diff --git a/arch/sparc/kernel/tsb.S b/arch/sparc/kernel/tsb.S index db872dbfafe9..f74115364b1e 100644 --- a/arch/sparc/kernel/tsb.S +++ b/arch/sparc/kernel/tsb.S @@ -117,7 +117,7 @@ tsb_miss_page_table_walk_sun4v_fastpath: /* Valid PTE is now in %g5. */ #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) - sethi %uhi(_PAGE_PMD_HUGE), %g7 + sethi %uhi(_PAGE_PMD_HUGE | _PAGE_PUD_HUGE), %g7 sllx %g7, 32, %g7 andcc %g5, %g7, %g0 diff --git a/arch/sparc/kernel/vmlinux.lds.S b/arch/sparc/kernel/vmlinux.lds.S index 03b3d65d1266..34d37e6c2d06 100644 --- a/arch/sparc/kernel/vmlinux.lds.S +++ b/arch/sparc/kernel/vmlinux.lds.S @@ -154,6 +154,11 @@ SECTIONS *(.get_tick_patch) __get_tick_patch_end = .; } + .pud_huge_patch : { + __pud_huge_patch = .; + *(.pud_huge_patch) + __pud_huge_patch_end = .; + } PERCPU_SECTION(SMP_CACHE_BYTES) #ifdef CONFIG_JUMP_LABEL diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c index 28ee8d8ffa07..7acb84db952c 100644 --- a/arch/sparc/mm/hugetlbpage.c +++ b/arch/sparc/mm/hugetlbpage.c @@ -143,6 +143,10 @@ static pte_t sun4v_hugepage_shift_to_tte(pte_t entry, unsigned int shift) pte_val(entry) = pte_val(entry) & ~_PAGE_SZALL_4V; switch (shift) { + case HPAGE_16GB_SHIFT: + hugepage_size = _PAGE_SZ16GB_4V; + pte_val(entry) |= _PAGE_PUD_HUGE; + break; case HPAGE_2GB_SHIFT: hugepage_size = _PAGE_SZ2GB_4V; pte_val(entry) |= _PAGE_PMD_HUGE; @@ -187,6 +191,9 @@ static unsigned int sun4v_huge_tte_to_shift(pte_t entry) unsigned int shift; switch (tte_szbits) { + case _PAGE_SZ16GB_4V: + shift = HPAGE_16GB_SHIFT; + break; case _PAGE_SZ2GB_4V: shift = HPAGE_2GB_SHIFT; break; @@ -263,7 +270,12 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, pgd = pgd_offset(mm, addr); pud = pud_alloc(mm, pgd, addr); - if (pud) { + if (!pud) + return NULL; + + if (sz >= PUD_SIZE) + pte = (pte_t *)pud; + else { pmd = pmd_alloc(mm, pud, addr); if (!pmd) return NULL; @@ -289,12 +301,16 @@ pte_t *huge_pte_offset(struct mm_struct *mm, if (!pgd_none(*pgd)) { pud = pud_offset(pgd, addr); if (!pud_none(*pud)) { - pmd = pmd_offset(pud, addr); - if (!pmd_none(*pmd)) { - if (is_hugetlb_pmd(*pmd)) - pte = (pte_t *)pmd; - else - pte = pte_offset_map(pmd, addr); + if (is_hugetlb_pud(*pud)) + pte = (pte_t *)pud; + else { + pmd = pmd_offset(pud, addr); + if (!pmd_none(*pmd)) { + if (is_hugetlb_pmd(*pmd)) + pte = (pte_t *)pmd; + else + pte = pte_offset_map(pmd, addr); + } } } } @@ -305,12 +321,20 @@ pte_t *huge_pte_offset(struct mm_struct *mm, void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t entry) { - unsigned int i, nptes, orig_shift, shift; - unsigned long size; + unsigned int nptes, orig_shift, shift; + unsigned long i, size; pte_t orig; size = huge_tte_to_size(entry); - shift = size >= HPAGE_SIZE ? PMD_SHIFT : PAGE_SHIFT; + + shift = PAGE_SHIFT; + if (size >= PUD_SIZE) + shift = PUD_SHIFT; + else if (size >= PMD_SIZE) + shift = PMD_SHIFT; + else + shift = PAGE_SHIFT; + nptes = size >> shift; if (!pte_present(*ptep) && pte_present(entry)) @@ -333,19 +357,23 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { - unsigned int i, nptes, hugepage_shift; + unsigned int i, nptes, orig_shift, shift; unsigned long size; pte_t entry; entry = *ptep; size = huge_tte_to_size(entry); - if (size >= HPAGE_SIZE) - nptes = size >> PMD_SHIFT; - else - nptes = size >> PAGE_SHIFT; - hugepage_shift = pte_none(entry) ? PAGE_SHIFT : - huge_tte_to_shift(entry); + shift = PAGE_SHIFT; + if (size >= PUD_SIZE) + shift = PUD_SHIFT; + else if (size >= PMD_SIZE) + shift = PMD_SHIFT; + else + shift = PAGE_SHIFT; + + nptes = size >> shift; + orig_shift = pte_none(entry) ? PAGE_SHIFT : huge_tte_to_shift(entry); if (pte_present(entry)) mm->context.hugetlb_pte_count -= nptes; @@ -354,11 +382,11 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, for (i = 0; i < nptes; i++) ptep[i] = __pte(0UL); - maybe_tlb_batch_add(mm, addr, ptep, entry, 0, hugepage_shift); + maybe_tlb_batch_add(mm, addr, ptep, entry, 0, orig_shift); /* An HPAGE_SIZE'ed page is composed of two REAL_HPAGE_SIZE'ed pages */ if (size == HPAGE_SIZE) maybe_tlb_batch_add(mm, addr + REAL_HPAGE_SIZE, ptep, entry, 0, - hugepage_shift); + orig_shift); return entry; } @@ -371,7 +399,8 @@ int pmd_huge(pmd_t pmd) int pud_huge(pud_t pud) { - return 0; + return !pud_none(pud) && + (pud_val(pud) & (_PAGE_VALID|_PAGE_PUD_HUGE)) != _PAGE_VALID; } static void hugetlb_free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, @@ -435,8 +464,11 @@ static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, next = pud_addr_end(addr, end); if (pud_none_or_clear_bad(pud)) continue; - hugetlb_free_pmd_range(tlb, pud, addr, next, floor, - ceiling); + if (is_hugetlb_pud(*pud)) + pud_clear(pud); + else + hugetlb_free_pmd_range(tlb, pud, addr, next, floor, + ceiling); } while (pud++, addr = next, addr != end); start &= PGDIR_MASK; diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c index afa0099f3748..b2ba410b26f4 100644 --- a/arch/sparc/mm/init_64.c +++ b/arch/sparc/mm/init_64.c @@ -348,6 +348,18 @@ static int __init hugetlbpage_init(void) arch_initcall(hugetlbpage_init); +static void __init pud_huge_patch(void) +{ + struct pud_huge_patch_entry *p; + unsigned long addr; + + p = &__pud_huge_patch; + addr = p->addr; + *(unsigned int *)addr = p->insn; + + __asm__ __volatile__("flush %0" : : "r" (addr)); +} + static int __init setup_hugepagesz(char *string) { unsigned long long hugepage_size; @@ -360,6 +372,11 @@ static int __init setup_hugepagesz(char *string) hugepage_shift = ilog2(hugepage_size); switch (hugepage_shift) { + case HPAGE_16GB_SHIFT: + hv_pgsz_mask = HV_PGSZ_MASK_16GB; + hv_pgsz_idx = HV_PGSZ_IDX_16GB; + pud_huge_patch(); + break; case HPAGE_2GB_SHIFT: hv_pgsz_mask = HV_PGSZ_MASK_2GB; hv_pgsz_idx = HV_PGSZ_IDX_2GB; @@ -400,6 +417,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t * { struct mm_struct *mm; unsigned long flags; + bool is_huge_tsb; pte_t pte = *ptep; if (tlb_type != hypervisor) { @@ -417,15 +435,37 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t * spin_lock_irqsave(&mm->context.lock, flags); + is_huge_tsb = false; #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) - if ((mm->context.hugetlb_pte_count || mm->context.thp_pte_count) && - is_hugetlb_pmd(__pmd(pte_val(pte)))) { - /* We are fabricating 8MB pages using 4MB real hw pages. */ - pte_val(pte) |= (address & (1UL << REAL_HPAGE_SHIFT)); - __update_mmu_tsb_insert(mm, MM_TSB_HUGE, REAL_HPAGE_SHIFT, - address, pte_val(pte)); - } else + if (mm->context.hugetlb_pte_count || mm->context.thp_pte_count) { + unsigned long hugepage_size = PAGE_SIZE; + + if (is_vm_hugetlb_page(vma)) + hugepage_size = huge_page_size(hstate_vma(vma)); + + if (hugepage_size >= PUD_SIZE) { + unsigned long mask = 0x1ffc00000UL; + + /* Transfer bits [32:22] from address to resolve + * at 4M granularity. + */ + pte_val(pte) &= ~mask; + pte_val(pte) |= (address & mask); + } else if (hugepage_size >= PMD_SIZE) { + /* We are fabricating 8MB pages using 4MB + * real hw pages. + */ + pte_val(pte) |= (address & (1UL << REAL_HPAGE_SHIFT)); + } + + if (hugepage_size >= PMD_SIZE) { + __update_mmu_tsb_insert(mm, MM_TSB_HUGE, + REAL_HPAGE_SHIFT, address, pte_val(pte)); + is_huge_tsb = true; + } + } #endif + if (!is_huge_tsb) __update_mmu_tsb_insert(mm, MM_TSB_BASE, PAGE_SHIFT, address, pte_val(pte)); From 4dbe87d5a70215af714b8ad44303ae7b333a2d20 Mon Sep 17 00:00:00 2001 From: Nitin Gupta Date: Fri, 11 Aug 2017 16:46:51 -0700 Subject: [PATCH 3/3] sparc64: Cleanup hugepage table walk functions Flatten out nested code structure in huge_pte_offset() and huge_pte_alloc(). Signed-off-by: Nitin Gupta Signed-off-by: David S. Miller --- arch/sparc/mm/hugetlbpage.c | 54 ++++++++++++++----------------------- 1 file changed, 20 insertions(+), 34 deletions(-) diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c index 7acb84db952c..bcd8cdbc377f 100644 --- a/arch/sparc/mm/hugetlbpage.c +++ b/arch/sparc/mm/hugetlbpage.c @@ -266,27 +266,19 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, pgd_t *pgd; pud_t *pud; pmd_t *pmd; - pte_t *pte = NULL; pgd = pgd_offset(mm, addr); pud = pud_alloc(mm, pgd, addr); if (!pud) return NULL; - if (sz >= PUD_SIZE) - pte = (pte_t *)pud; - else { - pmd = pmd_alloc(mm, pud, addr); - if (!pmd) - return NULL; - - if (sz >= PMD_SIZE) - pte = (pte_t *)pmd; - else - pte = pte_alloc_map(mm, pmd, addr); - } - - return pte; + return (pte_t *)pud; + pmd = pmd_alloc(mm, pud, addr); + if (!pmd) + return NULL; + if (sz >= PMD_SIZE) + return (pte_t *)pmd; + return pte_alloc_map(mm, pmd, addr); } pte_t *huge_pte_offset(struct mm_struct *mm, @@ -295,27 +287,21 @@ pte_t *huge_pte_offset(struct mm_struct *mm, pgd_t *pgd; pud_t *pud; pmd_t *pmd; - pte_t *pte = NULL; pgd = pgd_offset(mm, addr); - if (!pgd_none(*pgd)) { - pud = pud_offset(pgd, addr); - if (!pud_none(*pud)) { - if (is_hugetlb_pud(*pud)) - pte = (pte_t *)pud; - else { - pmd = pmd_offset(pud, addr); - if (!pmd_none(*pmd)) { - if (is_hugetlb_pmd(*pmd)) - pte = (pte_t *)pmd; - else - pte = pte_offset_map(pmd, addr); - } - } - } - } - - return pte; + if (pgd_none(*pgd)) + return NULL; + pud = pud_offset(pgd, addr); + if (pud_none(*pud)) + return NULL; + if (is_hugetlb_pud(*pud)) + return (pte_t *)pud; + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) + return NULL; + if (is_hugetlb_pmd(*pmd)) + return (pte_t *)pmd; + return pte_offset_map(pmd, addr); } void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,