arch/sparc/mm/generic.c

   1 /* $Id: generic.c,v 1.14 2001/12/21 04:56:15 davem Exp $
   2  * generic.c: Generic Sparc mm routines that are not dependent upon
   3  *            MMU type but are Sparc specific.
   4  *
   5  * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/mm.h>
  10 #include <linux/swap.h>
  11 #include <linux/pagemap.h>
  12
  13 #include <asm/pgalloc.h>
  14 #include <asm/pgtable.h>
  15 #include <asm/page.h>
  16 #include <asm/cacheflush.h>
  17 #include <asm/tlbflush.h>
  18
  19 static inline void forget_pte(pte_t page)
  20 {
  21 #if 0 /* old 2.4 code */
  22         if (pte_none(page))
  23                 return;
  24         if (pte_present(page)) {
  25                 unsigned long pfn = pte_pfn(page);
  26                 struct page *ptpage;
  27                 if (!pfn_valid(pfn))
  28                         return;
  29                 ptpage = pfn_to_page(pfn);
  30                 if (PageReserved(ptpage))
  31                         return;
  32                 page_cache_release(ptpage);
  33                 return;
  34         }
  35         swap_free(pte_to_swp_entry(page));
  36 #else
  37         if (!pte_none(page)) {
  38                 printk("forget_pte: old mapping existed!\n");
  39                 BUG();
  40         }
  41 #endif
  42 }
  43
  44 /* Remap IO memory, the same way as remap_pfn_range(), but use
  45  * the obio memory space.
  46  *
  47  * They use a pgprot that sets PAGE_IO and does not check the
  48  * mem_map table as this is independent of normal memory.
  49  */
  50 static inline void io_remap_pte_range(struct mm_struct *mm, pte_t * pte, unsigned long address, unsigned long size,
  51         unsigned long offset, pgprot_t prot, int space)
  52 {
  53         unsigned long end;
  54
  55         address &= ~PMD_MASK;
  56         end = address + size;
  57         if (end > PMD_SIZE)
  58                 end = PMD_SIZE;
  59         do {
  60                 pte_t oldpage = *pte;
  61                 pte_clear(mm, address, pte);
  62                 set_pte(pte, mk_pte_io(offset, prot, space));
  63                 forget_pte(oldpage);
  64                 address += PAGE_SIZE;
  65                 offset += PAGE_SIZE;
  66                 pte++;
  67         } while (address < end);
  68 }
  69
  70 static inline int io_remap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address, unsigned long size,
  71         unsigned long offset, pgprot_t prot, int space)
  72 {
  73         unsigned long end;
  74
  75         address &= ~PGDIR_MASK;
  76         end = address + size;
  77         if (end > PGDIR_SIZE)
  78                 end = PGDIR_SIZE;
  79         offset -= address;
  80         do {
  81                 pte_t * pte = pte_alloc_map(mm, pmd, address);
  82                 if (!pte)
  83                         return -ENOMEM;
  84                 io_remap_pte_range(mm, pte, address, end - address, address + offset, prot, space);
  85                 address = (address + PMD_SIZE) & PMD_MASK;
  86                 pmd++;
  87         } while (address < end);
  88         return 0;
  89 }
  90
  91 int io_remap_page_range(struct vm_area_struct *vma, unsigned long from, unsigned long offset, unsigned long size, pgprot_t prot, int space)
  92 {
  93         int error = 0;
  94         pgd_t * dir;
  95         unsigned long beg = from;
  96         unsigned long end = from + size;
  97         struct mm_struct *mm = vma->vm_mm;
  98
  99         prot = __pgprot(pg_iobits);
 100         offset -= from;
 101         dir = pgd_offset(mm, from);
 102         flush_cache_range(vma, beg, end);
 103
 104         spin_lock(&mm->page_table_lock);
 105         while (from < end) {
 106                 pmd_t *pmd = pmd_alloc(current->mm, dir, from);
 107                 error = -ENOMEM;
 108                 if (!pmd)
 109                         break;
 110                 error = io_remap_pmd_range(mm, pmd, from, end - from, offset + from, prot, space);
 111                 if (error)
 112                         break;
 113                 from = (from + PGDIR_SIZE) & PGDIR_MASK;
 114                 dir++;
 115         }
 116         spin_unlock(&mm->page_table_lock);
 117
 118         flush_tlb_range(vma, beg, end);
 119         return error;
 120 }
 121
 122 int io_remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
 123                         unsigned long pfn, unsigned long size, pgprot_t prot)
 124 {
 125         int error = 0;
 126         pgd_t * dir;
 127         unsigned long beg = from;
 128         unsigned long end = from + size;
 129         struct mm_struct *mm = vma->vm_mm;
 130         int space = GET_IOSPACE(pfn);
 131         unsigned long offset = GET_PFN(pfn) << PAGE_SHIFT;
 132
 133         prot = __pgprot(pg_iobits);
 134         offset -= from;
 135         dir = pgd_offset(mm, from);
 136         flush_cache_range(vma, beg, end);
 137
 138         spin_lock(&mm->page_table_lock);
 139         while (from < end) {
 140                 pmd_t *pmd = pmd_alloc(current->mm, dir, from);
 141                 error = -ENOMEM;
 142                 if (!pmd)
 143                         break;
 144                 error = io_remap_pmd_range(mm, pmd, from, end - from, offset + from, prot, space);
 145                 if (error)
 146                         break;
 147                 from = (from + PGDIR_SIZE) & PGDIR_MASK;
 148                 dir++;
 149         }
 150         spin_unlock(&mm->page_table_lock);
 151
 152         flush_tlb_range(vma, beg, end);
 153         return error;
 154 }