release/src-rt-6.x.4708/linux/linux-2.6.36/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/err.h>
  20 #include <linux/sysctl.h>
  21 #include <asm/mman.h>
  22 #include <asm/tlb.h>
  23 #include <asm/tlbflush.h>
  24
  25 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr,
  26                       unsigned long sz)
  27 {
  28         pgd_t *pgd;
  29         pud_t *pud;
  30         pte_t *pte = NULL;
  31
  32         pgd = pgd_offset(mm, addr);
  33         pud = pud_alloc(mm, pgd, addr);
  34         if (pud)
  35                 pte = (pte_t *)pmd_alloc(mm, pud, addr);
  36
  37         return pte;
  38 }
  39
  40 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
  41 {
  42         pgd_t *pgd;
  43         pud_t *pud;
  44         pmd_t *pmd = NULL;
  45
  46         pgd = pgd_offset(mm, addr);
  47         if (pgd_present(*pgd)) {
  48                 pud = pud_offset(pgd, addr);
  49                 if (pud_present(*pud))
  50                         pmd = pmd_offset(pud, addr);
  51         }
  52         return (pte_t *) pmd;
  53 }
  54
  55 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
  56 {
  57         return 0;
  58 }
  59
  60 /*
  61  * This function checks for proper alignment of input addr and len parameters.
  62  */
  63 int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
  64 {
  65         if (len & ~HPAGE_MASK)
  66                 return -EINVAL;
  67         if (addr & ~HPAGE_MASK)
  68                 return -EINVAL;
  69         return 0;
  70 }
  71
  72 struct page *
  73 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
  74 {
  75         return ERR_PTR(-EINVAL);
  76 }
  77
  78 int pmd_huge(pmd_t pmd)
  79 {
  80         return (pmd_val(pmd) & _PAGE_HUGE) != 0;
  81 }
  82
  83 int pud_huge(pud_t pud)
  84 {
  85         return (pud_val(pud) & _PAGE_HUGE) != 0;
  86 }
  87
  88 struct page *
  89 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
  90                 pmd_t *pmd, int write)
  91 {
  92         struct page *page;
  93
  94         page = pte_page(*(pte_t *)pmd);
  95         if (page)
  96                 page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
  97         return page;
  98 }