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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/config.h>
  12 #include <linux/init.h>
  13 #include <linux/fs.h>
  14 #include <linux/mm.h>
  15 #include <linux/hugetlb.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/slab.h>
  19 #include <linux/sysctl.h>
  20 #include <asm/mman.h>
  21 #include <asm/pgalloc.h>
  22 #include <asm/tlb.h>
  23 #include <asm/tlbflush.h>
  24
  25 unsigned int hpage_shift=HPAGE_SHIFT_DEFAULT;
  26
  27 pte_t *
  28 huge_pte_alloc (struct mm_struct *mm, unsigned long addr)
  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(unsigned long addr, unsigned long len)
  75 {
  76         if (len & ~HPAGE_MASK)
  77                 return -EINVAL;
  78         if (addr & ~HPAGE_MASK)
  79                 return -EINVAL;
  80         if (REGION_NUMBER(addr) != RGN_HPAGE)
  81                 return -EINVAL;
  82
  83         return 0;
  84 }
  85
  86 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int write)
  87 {
  88         struct page *page;
  89         pte_t *ptep;
  90
  91         if (REGION_NUMBER(addr) != RGN_HPAGE)
  92                 return ERR_PTR(-EINVAL);
  93
  94         ptep = huge_pte_offset(mm, addr);
  95         if (!ptep || pte_none(*ptep))
  96                 return NULL;
  97         page = pte_page(*ptep);
  98         page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT);
  99         return page;
 100 }
 101 int pmd_huge(pmd_t pmd)
 102 {
 103         return 0;
 104 }
 105 struct page *
 106 follow_huge_pmd(struct mm_struct *mm, unsigned long address, pmd_t *pmd, int write)
 107 {
 108         return NULL;
 109 }
 110
 111 void hugetlb_free_pgd_range(struct mmu_gather **tlb,
 112                         unsigned long addr, unsigned long end,
 113                         unsigned long floor, unsigned long ceiling)
 114 {
 115         /*
 116          * This is called to free hugetlb page tables.
 117          *
 118          * The offset of these addresses from the base of the hugetlb
 119          * region must be scaled down by HPAGE_SIZE/PAGE_SIZE so that
 120          * the standard free_pgd_range will free the right page tables.
 121          *
 122          * If floor and ceiling are also in the hugetlb region, they
 123          * must likewise be scaled down; but if outside, left unchanged.
 124          */
 125
 126         addr = htlbpage_to_page(addr);
 127         end  = htlbpage_to_page(end);
 128         if (REGION_NUMBER(floor) == RGN_HPAGE)
 129                 floor = htlbpage_to_page(floor);
 130         if (REGION_NUMBER(ceiling) == RGN_HPAGE)
 131                 ceiling = htlbpage_to_page(ceiling);
 132
 133         free_pgd_range(tlb, addr, end, floor, ceiling);
 134 }
 135
 136 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 137                 unsigned long pgoff, unsigned long flags)
 138 {
 139         struct vm_area_struct *vmm;
 140
 141         if (len > RGN_MAP_LIMIT)
 142                 return -ENOMEM;
 143         if (len & ~HPAGE_MASK)
 144                 return -EINVAL;
 145         /* This code assumes that RGN_HPAGE != 0. */
 146         if ((REGION_NUMBER(addr) != RGN_HPAGE) || (addr & (HPAGE_SIZE - 1)))
 147                 addr = HPAGE_REGION_BASE;
 148         else
 149                 addr = ALIGN(addr, HPAGE_SIZE);
 150         for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
 151                 /* At this point:  (!vmm || addr < vmm->vm_end). */
 152                 if (REGION_OFFSET(addr) + len > RGN_MAP_LIMIT)
 153                         return -ENOMEM;
 154                 if (!vmm || (addr + len) <= vmm->vm_start)
 155                         return addr;
 156                 addr = ALIGN(vmm->vm_end, HPAGE_SIZE);
 157         }
 158 }
 159
 160 static int __init hugetlb_setup_sz(char *str)
 161 {
 162         u64 tr_pages;
 163         unsigned long long size;
 164
 165         if (ia64_pal_vm_page_size(&tr_pages, NULL) != 0)
 166                 /*
 167                  * shouldn't happen, but just in case.
 168                  */
 169                 tr_pages = 0x15557000UL;
 170
 171         size = memparse(str, &str);
 172         if (*str || (size & (size-1)) || !(tr_pages & size) ||
 173                 size <= PAGE_SIZE ||
 174                 size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
 175                 printk(KERN_WARNING "Invalid huge page size specified\n");
 176                 return 1;
 177         }
 178
 179         hpage_shift = __ffs(size);
 180         /*
 181          * boot cpu already executed ia64_mmu_init, and has HPAGE_SHIFT_DEFAULT
 182          * override here with new page shift.
 183          */
 184         ia64_set_rr(HPAGE_REGION_BASE, hpage_shift << 2);
 185         return 1;
 186 }
 187 __setup("hugepagesz=", hugetlb_setup_sz);