arch/ia64/mm/hugetlbpage.c

   1 /*
   2  * IA-64 Huge TLB Page Support for Kernel.
   3  *
   4  * Copyright (C) 2002-2004 Rohit Seth <rohit.seth@intel.com>
   5  * Copyright (C) 2003-2004 Ken Chen <kenneth.w.chen@intel.com>
   6  *
   7  * Sep, 2003: add numa support
   8  * Feb, 2004: dynamic hugetlb page size via boot parameter
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/fs.h>
  13 #include <linux/mm.h>
  14 #include <linux/hugetlb.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/slab.h>
  17 #include <linux/sysctl.h>
  18 #include <asm/mman.h>
  19 #include <asm/pgalloc.h>
  20 #include <asm/tlb.h>
  21 #include <asm/tlbflush.h>
  22
  23 unsigned int hpage_shift=HPAGE_SHIFT_DEFAULT;
  24
  25 pte_t *
  26 huge_pte_alloc (struct mm_struct *mm, unsigned long addr)
  27 {
  28         unsigned long taddr = htlbpage_to_page(addr);
  29         pgd_t *pgd;
  30         pud_t *pud;
  31         pmd_t *pmd;
  32         pte_t *pte = NULL;
  33
  34         pgd = pgd_offset(mm, taddr);
  35         pud = pud_alloc(mm, pgd, taddr);
  36         if (pud) {
  37                 pmd = pmd_alloc(mm, pud, taddr);
  38                 if (pmd)
  39                         pte = pte_alloc_map(mm, pmd, taddr);
  40         }
  41         return pte;
  42 }
  43
  44 pte_t *
  45 huge_pte_offset (struct mm_struct *mm, unsigned long addr)
  46 {
  47         unsigned long taddr = htlbpage_to_page(addr);
  48         pgd_t *pgd;
  49         pud_t *pud;
  50         pmd_t *pmd;
  51         pte_t *pte = NULL;
  52
  53         pgd = pgd_offset(mm, taddr);
  54         if (pgd_present(*pgd)) {
  55                 pud = pud_offset(pgd, taddr);
  56                 if (pud_present(*pud)) {
  57                         pmd = pmd_offset(pud, taddr);
  58                         if (pmd_present(*pmd))
  59                                 pte = pte_offset_map(pmd, taddr);
  60                 }
  61         }
  62
  63         return pte;
  64 }
  65
  66 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
  67 {
  68         return 0;
  69 }
  70
  71 #define mk_pte_huge(entry) { pte_val(entry) |= _PAGE_P; }
  72
  73 /*
  74  * Don't actually need to do any preparation, but need to make sure
  75  * the address is in the right region.
  76  */
  77 int prepare_hugepage_range(unsigned long addr, unsigned long len, pgoff_t pgoff)
  78 {
  79         if (pgoff & (~HPAGE_MASK >> PAGE_SHIFT))
  80                 return -EINVAL;
  81         if (len & ~HPAGE_MASK)
  82                 return -EINVAL;
  83         if (addr & ~HPAGE_MASK)
  84                 return -EINVAL;
  85         if (REGION_NUMBER(addr) != RGN_HPAGE)
  86                 return -EINVAL;
  87
  88         return 0;
  89 }
  90
  91 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int write)
  92 {
  93         struct page *page;
  94         pte_t *ptep;
  95
  96         if (REGION_NUMBER(addr) != RGN_HPAGE)
  97                 return ERR_PTR(-EINVAL);
  98
  99         ptep = huge_pte_offset(mm, addr);
 100         if (!ptep || pte_none(*ptep))
 101                 return NULL;
 102         page = pte_page(*ptep);
 103         page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT);
 104         return page;
 105 }
 106 int pmd_huge(pmd_t pmd)
 107 {
 108         return 0;
 109 }
 110 struct page *
 111 follow_huge_pmd(struct mm_struct *mm, unsigned long address, pmd_t *pmd, int write)
 112 {
 113         return NULL;
 114 }
 115
 116 void hugetlb_free_pgd_range(struct mmu_gather **tlb,
 117                         unsigned long addr, unsigned long end,
 118                         unsigned long floor, unsigned long ceiling)
 119 {
 120         /*
 121          * This is called to free hugetlb page tables.
 122          *
 123          * The offset of these addresses from the base of the hugetlb
 124          * region must be scaled down by HPAGE_SIZE/PAGE_SIZE so that
 125          * the standard free_pgd_range will free the right page tables.
 126          *
 127          * If floor and ceiling are also in the hugetlb region, they
 128          * must likewise be scaled down; but if outside, left unchanged.
 129          */
 130
 131         addr = htlbpage_to_page(addr);
 132         end  = htlbpage_to_page(end);
 133         if (REGION_NUMBER(floor) == RGN_HPAGE)
 134                 floor = htlbpage_to_page(floor);
 135         if (REGION_NUMBER(ceiling) == RGN_HPAGE)
 136                 ceiling = htlbpage_to_page(ceiling);
 137
 138         free_pgd_range(tlb, addr, end, floor, ceiling);
 139 }
 140
 141 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 142                 unsigned long pgoff, unsigned long flags)
 143 {
 144         struct vm_area_struct *vmm;
 145
 146         if (len > RGN_MAP_LIMIT)
 147                 return -ENOMEM;
 148         if (len & ~HPAGE_MASK)
 149                 return -EINVAL;
 150
 151         /* Handle MAP_FIXED */
 152         if (flags & MAP_FIXED) {
 153                 if (prepare_hugepage_range(addr, len, pgoff))
 154                         return -EINVAL;
 155                 return addr;
 156         }
 157
 158         /* This code assumes that RGN_HPAGE != 0. */
 159         if ((REGION_NUMBER(addr) != RGN_HPAGE) || (addr & (HPAGE_SIZE - 1)))
 160                 addr = HPAGE_REGION_BASE;
 161         else
 162                 addr = ALIGN(addr, HPAGE_SIZE);
 163         for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
 164                 /* At this point:  (!vmm || addr < vmm->vm_end). */
 165                 if (REGION_OFFSET(addr) + len > RGN_MAP_LIMIT)
 166                         return -ENOMEM;
 167                 if (!vmm || (addr + len) <= vmm->vm_start)
 168                         return addr;
 169                 addr = ALIGN(vmm->vm_end, HPAGE_SIZE);
 170         }
 171 }
 172
 173 static int __init hugetlb_setup_sz(char *str)
 174 {
 175         u64 tr_pages;
 176         unsigned long long size;
 177
 178         if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
 179                 /*
 180                  * shouldn't happen, but just in case.
 181                  */
 182                 tr_pages = 0x15557000UL;
 183
 184         size = memparse(str, &str);
 185         if (*str || (size & (size-1)) || !(tr_pages & size) ||
 186                 size <= PAGE_SIZE ||
 187                 size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
 188                 printk(KERN_WARNING "Invalid huge page size specified\n");
 189                 return 1;
 190         }
 191
 192         hpage_shift = __ffs(size);
 193         /*
 194          * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
 195          * override here with new page shift.
 196          */
 197         ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2);
 198         return 1;
 199 }
 200 __setup("hugepagesz=", hugetlb_setup_sz);