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/fs.h>
  15 #include <linux/mm.h>
  16 #include <linux/hugetlb.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/err.h>
  19 #include <linux/sysctl.h>
  20 #include <asm/mman.h>
  21 #include <asm/tlb.h>
  22 #include <asm/tlbflush.h>
  23
  24 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr,
  25                       unsigned long sz)
  26 {
  27         pgd_t *pgd;
  28         pud_t *pud;
  29         pte_t *pte = NULL;
  30
  31         pgd = pgd_offset(mm, addr);
  32         pud = pud_alloc(mm, pgd, addr);
  33         if (pud)
  34                 pte = (pte_t *)pmd_alloc(mm, pud, addr);
  35
  36         return pte;
  37 }
  38
  39 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
  40 {
  41         pgd_t *pgd;
  42         pud_t *pud;
  43         pmd_t *pmd = NULL;
  44
  45         pgd = pgd_offset(mm, addr);
  46         if (pgd_present(*pgd)) {
  47                 pud = pud_offset(pgd, addr);
  48                 if (pud_present(*pud))
  49                         pmd = pmd_offset(pud, addr);
  50         }
  51         return (pte_t *) pmd;
  52 }
  53
  54 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
  55 {
  56         return 0;
  57 }
  58
  59 /*
  60  * This function checks for proper alignment of input addr and len parameters.
  61  */
  62 int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
  63 {
  64         if (len & ~HPAGE_MASK)
  65                 return -EINVAL;
  66         if (addr & ~HPAGE_MASK)
  67                 return -EINVAL;
  68         return 0;
  69 }
  70
  71 struct page *
  72 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
  73 {
  74         return ERR_PTR(-EINVAL);
  75 }
  76
  77 int pmd_huge(pmd_t pmd)
  78 {
  79         return (pmd_val(pmd) & _PAGE_HUGE) != 0;
  80 }
  81
  82 int pud_huge(pud_t pud)
  83 {
  84         return (pud_val(pud) & _PAGE_HUGE) != 0;
  85 }
  86
  87 int pmd_huge_support(void)
  88 {
  89         return 1;
  90 }
  91
  92 struct page *
  93 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
  94                 pmd_t *pmd, int write)
  95 {
  96         struct page *page;
  97
  98         page = pte_page(*(pte_t *)pmd);
  99         if (page)
 100                 page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
 101         return page;
 102 }