arch/mips/mm/hugetlbpage.c

   1 /*
   2  * MIPS Huge TLB Page Support for Kernel.
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
   9  * Copyright 2005, Embedded Alley Solutions, Inc.
  10  * Matt Porter <mporter@embeddedalley.com>
  11  * Copyright (C) 2008, 2009 Cavium Networks, Inc.
  12  */
  13
  14 #include <linux/init.h>
  15 #include <linux/fs.h>
  16 #include <linux/mm.h>
  17 #include <linux/hugetlb.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/slab.h>
  20 #include <linux/err.h>
  21 #include <linux/sysctl.h>
  22 #include <asm/mman.h>
  23 #include <asm/tlb.h>
  24 #include <asm/tlbflush.h>
  25
  26 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr,
  27                       unsigned long sz)
  28 {
  29         pgd_t *pgd;
  30         pud_t *pud;
  31         pte_t *pte = NULL;
  32
  33         pgd = pgd_offset(mm, addr);
  34         pud = pud_alloc(mm, pgd, addr);
  35         if (pud)
  36                 pte = (pte_t *)pmd_alloc(mm, pud, addr);
  37
  38         return pte;
  39 }
  40
  41 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
  42 {
  43         pgd_t *pgd;
  44         pud_t *pud;
  45         pmd_t *pmd = NULL;
  46
  47         pgd = pgd_offset(mm, addr);
  48         if (pgd_present(*pgd)) {
  49                 pud = pud_offset(pgd, addr);
  50                 if (pud_present(*pud))
  51                         pmd = pmd_offset(pud, addr);
  52         }
  53         return (pte_t *) pmd;
  54 }
  55
  56 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
  57 {
  58         return 0;
  59 }
  60
  61 /*
  62  * This function checks for proper alignment of input addr and len parameters.
  63  */
  64 int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
  65 {
  66         if (len & ~HPAGE_MASK)
  67                 return -EINVAL;
  68         if (addr & ~HPAGE_MASK)
  69                 return -EINVAL;
  70         return 0;
  71 }
  72
  73 struct page *
  74 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
  75 {
  76         return ERR_PTR(-EINVAL);
  77 }
  78
  79 int pmd_huge(pmd_t pmd)
  80 {
  81         return (pmd_val(pmd) & _PAGE_HUGE) != 0;
  82 }
  83
  84 int pud_huge(pud_t pud)
  85 {
  86         return (pud_val(pud) & _PAGE_HUGE) != 0;
  87 }
  88
  89 struct page *
  90 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
  91                 pmd_t *pmd, int write)
  92 {
  93         struct page *page;
  94
  95         page = pte_page(*(pte_t *)pmd);
  96         if (page)
  97                 page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
  98         return page;
  99 }
 100