diff options
Diffstat (limited to 'arch/s390/mm')
-rw-r--r-- | arch/s390/mm/dump_pagetables.c | 23 | ||||
-rw-r--r-- | arch/s390/mm/fault.c | 2 | ||||
-rw-r--r-- | arch/s390/mm/gmap.c | 11 | ||||
-rw-r--r-- | arch/s390/mm/gup.c | 33 | ||||
-rw-r--r-- | arch/s390/mm/hugetlbpage.c | 33 | ||||
-rw-r--r-- | arch/s390/mm/init.c | 38 | ||||
-rw-r--r-- | arch/s390/mm/mmap.c | 4 | ||||
-rw-r--r-- | arch/s390/mm/pageattr.c | 30 | ||||
-rw-r--r-- | arch/s390/mm/pgalloc.c | 57 | ||||
-rw-r--r-- | arch/s390/mm/pgtable.c | 6 | ||||
-rw-r--r-- | arch/s390/mm/vmem.c | 44 |
11 files changed, 194 insertions, 87 deletions
diff --git a/arch/s390/mm/dump_pagetables.c b/arch/s390/mm/dump_pagetables.c index 1b553d847140..049c3c455b32 100644 --- a/arch/s390/mm/dump_pagetables.c +++ b/arch/s390/mm/dump_pagetables.c @@ -149,7 +149,7 @@ static void walk_pmd_level(struct seq_file *m, struct pg_state *st, } static void walk_pud_level(struct seq_file *m, struct pg_state *st, - pgd_t *pgd, unsigned long addr) + p4d_t *p4d, unsigned long addr) { unsigned int prot; pud_t *pud; @@ -157,7 +157,7 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st, for (i = 0; i < PTRS_PER_PUD && addr < max_addr; i++) { st->current_address = addr; - pud = pud_offset(pgd, addr); + pud = pud_offset(p4d, addr); if (!pud_none(*pud)) if (pud_large(*pud)) { prot = pud_val(*pud) & @@ -172,6 +172,23 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st, } } +static void walk_p4d_level(struct seq_file *m, struct pg_state *st, + pgd_t *pgd, unsigned long addr) +{ + p4d_t *p4d; + int i; + + for (i = 0; i < PTRS_PER_P4D && addr < max_addr; i++) { + st->current_address = addr; + p4d = p4d_offset(pgd, addr); + if (!p4d_none(*p4d)) + walk_pud_level(m, st, p4d, addr); + else + note_page(m, st, _PAGE_INVALID, 2); + addr += P4D_SIZE; + } +} + static void walk_pgd_level(struct seq_file *m) { unsigned long addr = 0; @@ -184,7 +201,7 @@ static void walk_pgd_level(struct seq_file *m) st.current_address = addr; pgd = pgd_offset_k(addr); if (!pgd_none(*pgd)) - walk_pud_level(m, &st, pgd, addr); + walk_p4d_level(m, &st, pgd, addr); else note_page(m, &st, _PAGE_INVALID, 1); addr += PGDIR_SIZE; diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 5845d3028ffc..14f25798b001 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -130,7 +130,7 @@ static int bad_address(void *p) static void dump_pagetable(unsigned long asce, unsigned long address) { - unsigned long *table = __va(asce & PAGE_MASK); + unsigned long *table = __va(asce & _ASCE_ORIGIN); pr_alert("AS:%016lx ", asce); switch (asce & _ASCE_TYPE_MASK) { diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 7f6db1e6c048..4fb3d3cdb370 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -125,7 +125,7 @@ static void gmap_radix_tree_free(struct radix_tree_root *root) struct radix_tree_iter iter; unsigned long indices[16]; unsigned long index; - void **slot; + void __rcu **slot; int i, nr; /* A radix tree is freed by deleting all of its entries */ @@ -150,7 +150,7 @@ static void gmap_rmap_radix_tree_free(struct radix_tree_root *root) struct radix_tree_iter iter; unsigned long indices[16]; unsigned long index; - void **slot; + void __rcu **slot; int i, nr; /* A radix tree is freed by deleting all of its entries */ @@ -537,6 +537,7 @@ int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr) unsigned long *table; spinlock_t *ptl; pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; int rc; @@ -573,7 +574,9 @@ int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr) mm = gmap->mm; pgd = pgd_offset(mm, vmaddr); VM_BUG_ON(pgd_none(*pgd)); - pud = pud_offset(pgd, vmaddr); + p4d = p4d_offset(pgd, vmaddr); + VM_BUG_ON(p4d_none(*p4d)); + pud = pud_offset(p4d, vmaddr); VM_BUG_ON(pud_none(*pud)); /* large puds cannot yet be handled */ if (pud_large(*pud)) @@ -1008,7 +1011,7 @@ EXPORT_SYMBOL_GPL(gmap_read_table); static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr, struct gmap_rmap *rmap) { - void **slot; + void __rcu **slot; BUG_ON(!gmap_is_shadow(sg)); slot = radix_tree_lookup_slot(&sg->host_to_rmap, vmaddr >> PAGE_SHIFT); diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c index b7b779c40a5b..8ecc25e760fa 100644 --- a/arch/s390/mm/gup.c +++ b/arch/s390/mm/gup.c @@ -166,15 +166,15 @@ static int gup_huge_pud(pud_t *pudp, pud_t pud, unsigned long addr, return 1; } -static inline int gup_pud_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr, +static inline int gup_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { unsigned long next; pud_t *pudp, pud; - pudp = (pud_t *) pgdp; - if ((pgd_val(pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R2) - pudp = (pud_t *) pgd_deref(pgd); + pudp = (pud_t *) p4dp; + if ((p4d_val(p4d) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R2) + pudp = (pud_t *) p4d_deref(p4d); pudp += pud_index(addr); do { pud = *pudp; @@ -194,6 +194,29 @@ static inline int gup_pud_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr, return 1; } +static inline int gup_p4d_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr, + unsigned long end, int write, struct page **pages, int *nr) +{ + unsigned long next; + p4d_t *p4dp, p4d; + + p4dp = (p4d_t *) pgdp; + if ((pgd_val(pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R1) + p4dp = (p4d_t *) pgd_deref(pgd); + p4dp += p4d_index(addr); + do { + p4d = *p4dp; + barrier(); + next = p4d_addr_end(addr, end); + if (p4d_none(p4d)) + return 0; + if (!gup_pud_range(p4dp, p4d, addr, next, write, pages, nr)) + return 0; + } while (p4dp++, addr = next, addr != end); + + return 1; +} + /* * Like get_user_pages_fast() except its IRQ-safe in that it won't fall * back to the regular GUP. @@ -228,7 +251,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, next = pgd_addr_end(addr, end); if (pgd_none(pgd)) break; - if (!gup_pud_range(pgdp, pgd, addr, next, write, pages, &nr)) + if (!gup_p4d_range(pgdp, pgd, addr, next, write, pages, &nr)) break; } while (pgdp++, addr = next, addr != end); local_irq_restore(flags); diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c index 9b4050caa4e9..44a8e6f0391e 100644 --- a/arch/s390/mm/hugetlbpage.c +++ b/arch/s390/mm/hugetlbpage.c @@ -162,33 +162,42 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz) { pgd_t *pgdp; + p4d_t *p4dp; pud_t *pudp; pmd_t *pmdp = NULL; pgdp = pgd_offset(mm, addr); - pudp = pud_alloc(mm, pgdp, addr); - if (pudp) { - if (sz == PUD_SIZE) - return (pte_t *) pudp; - else if (sz == PMD_SIZE) - pmdp = pmd_alloc(mm, pudp, addr); + p4dp = p4d_alloc(mm, pgdp, addr); + if (p4dp) { + pudp = pud_alloc(mm, p4dp, addr); + if (pudp) { + if (sz == PUD_SIZE) + return (pte_t *) pudp; + else if (sz == PMD_SIZE) + pmdp = pmd_alloc(mm, pudp, addr); + } } return (pte_t *) pmdp; } -pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) +pte_t *huge_pte_offset(struct mm_struct *mm, + unsigned long addr, unsigned long sz) { pgd_t *pgdp; + p4d_t *p4dp; pud_t *pudp; pmd_t *pmdp = NULL; pgdp = pgd_offset(mm, addr); if (pgd_present(*pgdp)) { - pudp = pud_offset(pgdp, addr); - if (pud_present(*pudp)) { - if (pud_large(*pudp)) - return (pte_t *) pudp; - pmdp = pmd_offset(pudp, addr); + p4dp = p4d_offset(pgdp, addr); + if (p4d_present(*p4dp)) { + pudp = pud_offset(p4dp, addr); + if (pud_present(*pudp)) { + if (pud_large(*pudp)) + return (pte_t *) pudp; + pmdp = pmd_offset(pudp, addr); + } } } return (pte_t *) pmdp; diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index ee6a1d3d4983..8111694ce55a 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -81,6 +81,7 @@ void __init paging_init(void) { unsigned long max_zone_pfns[MAX_NR_ZONES]; unsigned long pgd_type, asce_bits; + psw_t psw; init_mm.pgd = swapper_pg_dir; if (VMALLOC_END > (1UL << 42)) { @@ -100,7 +101,10 @@ void __init paging_init(void) __ctl_load(S390_lowcore.kernel_asce, 1, 1); __ctl_load(S390_lowcore.kernel_asce, 7, 7); __ctl_load(S390_lowcore.kernel_asce, 13, 13); - __arch_local_irq_stosm(0x04); + psw.mask = __extract_psw(); + psw_bits(psw).dat = 1; + psw_bits(psw).as = PSW_BITS_AS_HOME; + __load_psw_mask(psw.mask); sparse_memory_present_with_active_regions(MAX_NUMNODES); sparse_init(); @@ -162,43 +166,17 @@ unsigned long memory_block_size_bytes(void) } #ifdef CONFIG_MEMORY_HOTPLUG -int arch_add_memory(int nid, u64 start, u64 size, bool for_device) +int arch_add_memory(int nid, u64 start, u64 size, bool want_memblock) { - unsigned long zone_start_pfn, zone_end_pfn, nr_pages; unsigned long start_pfn = PFN_DOWN(start); unsigned long size_pages = PFN_DOWN(size); - pg_data_t *pgdat = NODE_DATA(nid); - struct zone *zone; - int rc, i; + int rc; rc = vmem_add_mapping(start, size); if (rc) return rc; - for (i = 0; i < MAX_NR_ZONES; i++) { - zone = pgdat->node_zones + i; - if (zone_idx(zone) != ZONE_MOVABLE) { - /* Add range within existing zone limits, if possible */ - zone_start_pfn = zone->zone_start_pfn; - zone_end_pfn = zone->zone_start_pfn + - zone->spanned_pages; - } else { - /* Add remaining range to ZONE_MOVABLE */ - zone_start_pfn = start_pfn; - zone_end_pfn = start_pfn + size_pages; - } - if (start_pfn < zone_start_pfn || start_pfn >= zone_end_pfn) - continue; - nr_pages = (start_pfn + size_pages > zone_end_pfn) ? - zone_end_pfn - start_pfn : size_pages; - rc = __add_pages(nid, zone, start_pfn, nr_pages); - if (rc) - break; - start_pfn += nr_pages; - size_pages -= nr_pages; - if (!size_pages) - break; - } + rc = __add_pages(nid, start_pfn, size_pages, want_memblock); if (rc) vmem_remove_mapping(start, size); return rc; diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index b854b1da281a..2e10d2b8ad35 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -120,7 +120,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, check_asce_limit: if (addr + len > current->mm->context.asce_limit) { - rc = crst_table_upgrade(mm); + rc = crst_table_upgrade(mm, addr + len); if (rc) return (unsigned long) rc; } @@ -184,7 +184,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, check_asce_limit: if (addr + len > current->mm->context.asce_limit) { - rc = crst_table_upgrade(mm); + rc = crst_table_upgrade(mm, addr + len); if (rc) return (unsigned long) rc; } diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c index 49e721f3645e..180481589246 100644 --- a/arch/s390/mm/pageattr.c +++ b/arch/s390/mm/pageattr.c @@ -229,14 +229,14 @@ static void modify_pud_page(pud_t *pudp, unsigned long addr, pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3); } -static int walk_pud_level(pgd_t *pgd, unsigned long addr, unsigned long end, +static int walk_pud_level(p4d_t *p4d, unsigned long addr, unsigned long end, unsigned long flags) { unsigned long next; pud_t *pudp; int rc = 0; - pudp = pud_offset(pgd, addr); + pudp = pud_offset(p4d, addr); do { if (pud_none(*pudp)) return -EINVAL; @@ -259,6 +259,26 @@ static int walk_pud_level(pgd_t *pgd, unsigned long addr, unsigned long end, return rc; } +static int walk_p4d_level(pgd_t *pgd, unsigned long addr, unsigned long end, + unsigned long flags) +{ + unsigned long next; + p4d_t *p4dp; + int rc = 0; + + p4dp = p4d_offset(pgd, addr); + do { + if (p4d_none(*p4dp)) + return -EINVAL; + next = p4d_addr_end(addr, end); + rc = walk_pud_level(p4dp, addr, next, flags); + p4dp++; + addr = next; + cond_resched(); + } while (addr < end && !rc); + return rc; +} + static DEFINE_MUTEX(cpa_mutex); static int change_page_attr(unsigned long addr, unsigned long end, @@ -278,7 +298,7 @@ static int change_page_attr(unsigned long addr, unsigned long end, if (pgd_none(*pgdp)) break; next = pgd_addr_end(addr, end); - rc = walk_pud_level(pgdp, addr, next, flags); + rc = walk_p4d_level(pgdp, addr, next, flags); if (rc) break; cond_resched(); @@ -319,6 +339,7 @@ void __kernel_map_pages(struct page *page, int numpages, int enable) unsigned long address; int nr, i, j; pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; pte_t *pte; @@ -326,7 +347,8 @@ void __kernel_map_pages(struct page *page, int numpages, int enable) for (i = 0; i < numpages;) { address = page_to_phys(page + i); pgd = pgd_offset_k(address); - pud = pud_offset(pgd, address); + p4d = p4d_offset(pgd, address); + pud = pud_offset(p4d, address); pmd = pmd_offset(pud, address); pte = pte_offset_kernel(pmd, address); nr = (unsigned long)pte >> ilog2(sizeof(long)); diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c index f502cbe657af..18918e394ce4 100644 --- a/arch/s390/mm/pgalloc.c +++ b/arch/s390/mm/pgalloc.c @@ -76,29 +76,46 @@ static void __crst_table_upgrade(void *arg) __tlb_flush_local(); } -int crst_table_upgrade(struct mm_struct *mm) +int crst_table_upgrade(struct mm_struct *mm, unsigned long end) { unsigned long *table, *pgd; + int rc, notify; - /* upgrade should only happen from 3 to 4 levels */ - BUG_ON(mm->context.asce_limit != (1UL << 42)); - - table = crst_table_alloc(mm); - if (!table) + /* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */ + BUG_ON(mm->context.asce_limit < (1UL << 42)); + if (end >= TASK_SIZE_MAX) return -ENOMEM; - - spin_lock_bh(&mm->page_table_lock); - pgd = (unsigned long *) mm->pgd; - crst_table_init(table, _REGION2_ENTRY_EMPTY); - pgd_populate(mm, (pgd_t *) table, (pud_t *) pgd); - mm->pgd = (pgd_t *) table; - mm->context.asce_limit = 1UL << 53; - mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH | - _ASCE_USER_BITS | _ASCE_TYPE_REGION2; - spin_unlock_bh(&mm->page_table_lock); - - on_each_cpu(__crst_table_upgrade, mm, 0); - return 0; + rc = 0; + notify = 0; + while (mm->context.asce_limit < end) { + table = crst_table_alloc(mm); + if (!table) { + rc = -ENOMEM; + break; + } + spin_lock_bh(&mm->page_table_lock); + pgd = (unsigned long *) mm->pgd; + if (mm->context.asce_limit == (1UL << 42)) { + crst_table_init(table, _REGION2_ENTRY_EMPTY); + p4d_populate(mm, (p4d_t *) table, (pud_t *) pgd); + mm->pgd = (pgd_t *) table; + mm->context.asce_limit = 1UL << 53; + mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH | + _ASCE_USER_BITS | _ASCE_TYPE_REGION2; + } else { + crst_table_init(table, _REGION1_ENTRY_EMPTY); + pgd_populate(mm, (pgd_t *) table, (p4d_t *) pgd); + mm->pgd = (pgd_t *) table; + mm->context.asce_limit = -PAGE_SIZE; + mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH | + _ASCE_USER_BITS | _ASCE_TYPE_REGION1; + } + notify = 1; + spin_unlock_bh(&mm->page_table_lock); + } + if (notify) + on_each_cpu(__crst_table_upgrade, mm, 0); + return rc; } void crst_table_downgrade(struct mm_struct *mm) @@ -274,7 +291,7 @@ static void __tlb_remove_table(void *_table) struct page *page = pfn_to_page(__pa(table) >> PAGE_SHIFT); switch (mask) { - case 0: /* pmd or pud */ + case 0: /* pmd, pud, or p4d */ free_pages((unsigned long) table, 2); break; case 1: /* lower 2K of a 4K page table */ diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 947b66a5cdba..d4d409ba206b 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -610,6 +610,7 @@ bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long addr) { spinlock_t *ptl; pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; pgste_t pgste; @@ -618,7 +619,10 @@ bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long addr) bool dirty; pgd = pgd_offset(mm, addr); - pud = pud_alloc(mm, pgd, addr); + p4d = p4d_alloc(mm, pgd, addr); + if (!p4d) + return false; + pud = pud_alloc(mm, p4d, addr); if (!pud) return false; pmd = pmd_alloc(mm, pud, addr); diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c index c33c94b4be60..d8398962a723 100644 --- a/arch/s390/mm/vmem.c +++ b/arch/s390/mm/vmem.c @@ -38,6 +38,17 @@ static void __ref *vmem_alloc_pages(unsigned int order) return (void *) memblock_alloc(size, size); } +static inline p4d_t *vmem_p4d_alloc(void) +{ + p4d_t *p4d = NULL; + + p4d = vmem_alloc_pages(2); + if (!p4d) + return NULL; + clear_table((unsigned long *) p4d, _REGION2_ENTRY_EMPTY, PAGE_SIZE * 4); + return p4d; +} + static inline pud_t *vmem_pud_alloc(void) { pud_t *pud = NULL; @@ -85,6 +96,7 @@ static int vmem_add_mem(unsigned long start, unsigned long size) unsigned long end = start + size; unsigned long address = start; pgd_t *pg_dir; + p4d_t *p4_dir; pud_t *pu_dir; pmd_t *pm_dir; pte_t *pt_dir; @@ -102,12 +114,19 @@ static int vmem_add_mem(unsigned long start, unsigned long size) while (address < end) { pg_dir = pgd_offset_k(address); if (pgd_none(*pg_dir)) { + p4_dir = vmem_p4d_alloc(); + if (!p4_dir) + goto out; + pgd_populate(&init_mm, pg_dir, p4_dir); + } + p4_dir = p4d_offset(pg_dir, address); + if (p4d_none(*p4_dir)) { pu_dir = vmem_pud_alloc(); if (!pu_dir) goto out; - pgd_populate(&init_mm, pg_dir, pu_dir); + p4d_populate(&init_mm, p4_dir, pu_dir); } - pu_dir = pud_offset(pg_dir, address); + pu_dir = pud_offset(p4_dir, address); if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address && !(address & ~PUD_MASK) && (address + PUD_SIZE <= end) && !debug_pagealloc_enabled()) { @@ -161,6 +180,7 @@ static void vmem_remove_range(unsigned long start, unsigned long size) unsigned long end = start + size; unsigned long address = start; pgd_t *pg_dir; + p4d_t *p4_dir; pud_t *pu_dir; pmd_t *pm_dir; pte_t *pt_dir; @@ -172,7 +192,12 @@ static void vmem_remove_range(unsigned long start, unsigned long size) address += PGDIR_SIZE; continue; } - pu_dir = pud_offset(pg_dir, address); + p4_dir = p4d_offset(pg_dir, address); + if (p4d_none(*p4_dir)) { + address += P4D_SIZE; + continue; + } + pu_dir = pud_offset(p4_dir, address); if (pud_none(*pu_dir)) { address += PUD_SIZE; continue; @@ -213,6 +238,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) unsigned long pgt_prot, sgt_prot; unsigned long address = start; pgd_t *pg_dir; + p4d_t *p4_dir; pud_t *pu_dir; pmd_t *pm_dir; pte_t *pt_dir; @@ -227,13 +253,21 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) for (address = start; address < end;) { pg_dir = pgd_offset_k(address); if (pgd_none(*pg_dir)) { + p4_dir = vmem_p4d_alloc(); + if (!p4_dir) + goto out; + pgd_populate(&init_mm, pg_dir, p4_dir); + } + + p4_dir = p4d_offset(pg_dir, address); + if (p4d_none(*p4_dir)) { pu_dir = vmem_pud_alloc(); if (!pu_dir) goto out; - pgd_populate(&init_mm, pg_dir, pu_dir); + p4d_populate(&init_mm, p4_dir, pu_dir); } - pu_dir = pud_offset(pg_dir, address); + pu_dir = pud_offset(p4_dir, address); if (pud_none(*pu_dir)) { pm_dir = vmem_pmd_alloc(); if (!pm_dir) |