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