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   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 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
  69 {
  70         return 0;
  71 }
  72
  73 #define mk_pte_huge(entry) { pte_val(entry) |= _PAGE_P; }
  74
  75 /*
  76  * Don't actually need to do any preparation, but need to make sure
  77  * the address is in the right region.
  78  */
  79 int prepare_hugepage_range(struct file *file,
  80                         unsigned long addr, unsigned long len)
  81 {
  82         if (len & ~HPAGE_MASK)
  83                 return -EINVAL;
  84         if (addr & ~HPAGE_MASK)
  85                 return -EINVAL;
  86         if (REGION_NUMBER(addr) != RGN_HPAGE)
  87                 return -EINVAL;
  88
  89         return 0;
  90 }
  91
  92 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int write)
  93 {
  94         struct page *page;
  95         pte_t *ptep;
  96
  97         if (REGION_NUMBER(addr) != RGN_HPAGE)
  98                 return ERR_PTR(-EINVAL);
  99
 100         ptep = huge_pte_offset(mm, addr);
 101         if (!ptep || pte_none(*ptep))
 102                 return NULL;
 103         page = pte_page(*ptep);
 104         page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT);
 105         return page;
 106 }
 107 int pmd_huge(pmd_t pmd)
 108 {
 109         return 0;
 110 }
 111
 112 int pud_huge(pud_t pud)
 113 {
 114         return 0;
 115 }
 116
 117 struct page *
 118 follow_huge_pmd(struct mm_struct *mm, unsigned long address, pmd_t *pmd, int write)
 119 {
 120         return NULL;
 121 }
 122
 123 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 124                         unsigned long addr, unsigned long end,
 125                         unsigned long floor, unsigned long ceiling)
 126 {
 127         /*
 128          * This is called to free hugetlb page tables.
 129          *
 130          * The offset of these addresses from the base of the hugetlb
 131          * region must be scaled down by HPAGE_SIZE/PAGE_SIZE so that
 132          * the standard free_pgd_range will free the right page tables.
 133          *
 134          * If floor and ceiling are also in the hugetlb region, they
 135          * must likewise be scaled down; but if outside, left unchanged.
 136          */
 137
 138         addr = htlbpage_to_page(addr);
 139         end  = htlbpage_to_page(end);
 140         if (REGION_NUMBER(floor) == RGN_HPAGE)
 141                 floor = htlbpage_to_page(floor);
 142         if (REGION_NUMBER(ceiling) == RGN_HPAGE)
 143                 ceiling = htlbpage_to_page(ceiling);
 144
 145         free_pgd_range(tlb, addr, end, floor, ceiling);
 146 }
 147
 148 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 149                 unsigned long pgoff, unsigned long flags)
 150 {
 151         struct vm_area_struct *vmm;
 152
 153         if (len > RGN_MAP_LIMIT)
 154                 return -ENOMEM;
 155         if (len & ~HPAGE_MASK)
 156                 return -EINVAL;
 157
 158         /* Handle MAP_FIXED */
 159         if (flags & MAP_FIXED) {
 160                 if (prepare_hugepage_range(file, addr, len))
 161                         return -EINVAL;
 162                 return addr;
 163         }
 164
 165         /* This code assumes that RGN_HPAGE != 0. */
 166         if ((REGION_NUMBER(addr) != RGN_HPAGE) || (addr & (HPAGE_SIZE - 1)))
 167                 addr = HPAGE_REGION_BASE;
 168         else
 169                 addr = ALIGN(addr, HPAGE_SIZE);
 170         for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
 171                 /* At this point:  (!vmm || addr < vmm->vm_end). */
 172                 if (REGION_OFFSET(addr) + len > RGN_MAP_LIMIT)
 173                         return -ENOMEM;
 174                 if (!vmm || (addr + len) <= vmm->vm_start)
 175                         return addr;
 176                 addr = ALIGN(vmm->vm_end, HPAGE_SIZE);
 177         }
 178 }
 179
 180 static int __init hugetlb_setup_sz(char *str)
 181 {
 182         u64 tr_pages;
 183         unsigned long long size;
 184
 185         if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
 186                 /*
 187                  * shouldn't happen, but just in case.
 188                  */
 189                 tr_pages = 0x15557000UL;
 190
 191         size = memparse(str, &str);
 192         if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
 193                 size <= PAGE_SIZE ||
 194                 size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
 195                 printk(KERN_WARNING "Invalid huge page size specified\n");
 196                 return 1;
 197         }
 198
 199         hpage_shift = __ffs(size);
 200         /*
 201          * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
 202          * override here with new page shift.
 203          */
 204         ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2);
 205         return 0;
 206 }
 207 early_param("hugepagesz", hugetlb_setup_sz);