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/module.h>
  17 #include <linux/sysctl.h>
  18 #include <linux/log2.h>
  19 #include <asm/mman.h>
  20 #include <asm/pgalloc.h>
  21 #include <asm/tlb.h>
  22 #include <asm/tlbflush.h>
  23
  24 unsigned int hpage_shift = HPAGE_SHIFT_DEFAULT;
  25 EXPORT_SYMBOL(hpage_shift);
  26
  27 pte_t *
  28 huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
  29 {
  30         unsigned long taddr = htlbpage_to_page(addr);
  31         pgd_t *pgd;
  32         pud_t *pud;
  33         pmd_t *pmd;
  34         pte_t *pte = NULL;
  35
  36         pgd = pgd_offset(mm, taddr);
  37         pud = pud_alloc(mm, pgd, taddr);
  38         if (pud) {
  39                 pmd = pmd_alloc(mm, pud, taddr);
  40                 if (pmd)
  41                         pte = pte_alloc_map(mm, pmd, taddr);
  42         }
  43         return pte;
  44 }
  45
  46 pte_t *
  47 huge_pte_offset (struct mm_struct *mm, unsigned long addr)
  48 {
  49         unsigned long taddr = htlbpage_to_page(addr);
  50         pgd_t *pgd;
  51         pud_t *pud;
  52         pmd_t *pmd;
  53         pte_t *pte = NULL;
  54
  55         pgd = pgd_offset(mm, taddr);
  56         if (pgd_present(*pgd)) {
  57                 pud = pud_offset(pgd, taddr);
  58                 if (pud_present(*pud)) {
  59                         pmd = pmd_offset(pud, taddr);
  60                         if (pmd_present(*pmd))
  61                                 pte = pte_offset_map(pmd, taddr);
  62                 }
  63         }
  64
  65         return pte;
  66 }
  67
  68 #define mk_pte_huge(entry) { pte_val(entry) |= _PAGE_P; }
  69
  70 /*
  71  * Don't actually need to do any preparation, but need to make sure
  72  * the address is in the right region.
  73  */
  74 int prepare_hugepage_range(struct file *file,
  75                         unsigned long addr, unsigned long len)
  76 {
  77         if (len & ~HPAGE_MASK)
  78                 return -EINVAL;
  79         if (addr & ~HPAGE_MASK)
  80                 return -EINVAL;
  81         if (REGION_NUMBER(addr) != RGN_HPAGE)
  82                 return -EINVAL;
  83
  84         return 0;
  85 }
  86
  87 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int write)
  88 {
  89         struct page *page;
  90         pte_t *ptep;
  91
  92         if (REGION_NUMBER(addr) != RGN_HPAGE)
  93                 return ERR_PTR(-EINVAL);
  94
  95         ptep = huge_pte_offset(mm, addr);
  96         if (!ptep || pte_none(*ptep))
  97                 return NULL;
  98         page = pte_page(*ptep);
  99         page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT);
 100         return page;
 101 }
 102 int pmd_huge(pmd_t pmd)
 103 {
 104         return 0;
 105 }
 106
 107 int pud_huge(pud_t pud)
 108 {
 109         return 0;
 110 }
 111
 112 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 113                         unsigned long addr, unsigned long end,
 114                         unsigned long floor, unsigned long ceiling)
 115 {
 116         /*
 117          * This is called to free hugetlb page tables.
 118          *
 119          * The offset of these addresses from the base of the hugetlb
 120          * region must be scaled down by HPAGE_SIZE/PAGE_SIZE so that
 121          * the standard free_pgd_range will free the right page tables.
 122          *
 123          * If floor and ceiling are also in the hugetlb region, they
 124          * must likewise be scaled down; but if outside, left unchanged.
 125          */
 126
 127         addr = htlbpage_to_page(addr);
 128         end  = htlbpage_to_page(end);
 129         if (REGION_NUMBER(floor) == RGN_HPAGE)
 130                 floor = htlbpage_to_page(floor);
 131         if (REGION_NUMBER(ceiling) == RGN_HPAGE)
 132                 ceiling = htlbpage_to_page(ceiling);
 133
 134         free_pgd_range(tlb, addr, end, floor, ceiling);
 135 }
 136
 137 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 138                 unsigned long pgoff, unsigned long flags)
 139 {
 140         struct vm_unmapped_area_info info;
 141
 142         if (len > RGN_MAP_LIMIT)
 143                 return -ENOMEM;
 144         if (len & ~HPAGE_MASK)
 145                 return -EINVAL;
 146
 147         /* Handle MAP_FIXED */
 148         if (flags & MAP_FIXED) {
 149                 if (prepare_hugepage_range(file, addr, len))
 150                         return -EINVAL;
 151                 return addr;
 152         }
 153
 154         /* This code assumes that RGN_HPAGE != 0. */
 155         if ((REGION_NUMBER(addr) != RGN_HPAGE) || (addr & (HPAGE_SIZE - 1)))
 156                 addr = HPAGE_REGION_BASE;
 157
 158         info.flags = 0;
 159         info.length = len;
 160         info.low_limit = addr;
 161         info.high_limit = HPAGE_REGION_BASE + RGN_MAP_LIMIT;
 162         info.align_mask = PAGE_MASK & (HPAGE_SIZE - 1);
 163         info.align_offset = 0;
 164         return vm_unmapped_area(&info);
 165 }
 166
 167 static int __init hugetlb_setup_sz(char *str)
 168 {
 169         u64 tr_pages;
 170         unsigned long long size;
 171
 172         if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
 173                 /*
 174                  * shouldn't happen, but just in case.
 175                  */
 176                 tr_pages = 0x15557000UL;
 177
 178         size = memparse(str, &str);
 179         if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
 180                 size <= PAGE_SIZE ||
 181                 size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
 182                 printk(KERN_WARNING "Invalid huge page size specified\n");
 183                 return 1;
 184         }
 185
 186         hpage_shift = __ffs(size);
 187         /*
 188          * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
 189          * override here with new page shift.
 190          */
 191         ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2);
 192         return 0;
 193 }
 194 early_param("hugepagesz", hugetlb_setup_sz);