arch/sparc/mm/generic.c

   1 /* $Id: generic.c,v 1.10 2000/08/09 00:00:15 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
  12 #include <asm/pgalloc.h>
  13 #include <asm/pgtable.h>
  14 #include <asm/page.h>
  15
  16 static inline void forget_pte(pte_t page)
  17 {
  18         if (pte_none(page))
  19                 return;
  20         if (pte_present(page)) {
  21                 struct page *ptpage = pte_page(page);
  22                 if ((!VALID_PAGE(ptpage)) || PageReserved(ptpage))
  23                         return;
  24                 /*
  25                  * free_page() used to be able to clear swap cache
  26                  * entries.  We may now have to do it manually.
  27                  */
  28                 free_page_and_swap_cache(ptpage);
  29                 return;
  30         }
  31         swap_free(pte_to_swp_entry(page));
  32 }
  33
  34 /* Remap IO memory, the same way as remap_page_range(), but use
  35  * the obio memory space.
  36  *
  37  * They use a pgprot that sets PAGE_IO and does not check the
  38  * mem_map table as this is independent of normal memory.
  39  */
  40 static inline void io_remap_pte_range(pte_t * pte, unsigned long address, unsigned long size,
  41         unsigned long offset, pgprot_t prot, int space)
  42 {
  43         unsigned long end;
  44
  45         address &= ~PMD_MASK;
  46         end = address + size;
  47         if (end > PMD_SIZE)
  48                 end = PMD_SIZE;
  49         do {
  50                 pte_t oldpage = *pte;
  51                 pte_clear(pte);
  52                 set_pte(pte, mk_pte_io(offset, prot, space));
  53                 forget_pte(oldpage);
  54                 address += PAGE_SIZE;
  55                 offset += PAGE_SIZE;
  56                 pte++;
  57         } while (address < end);
  58 }
  59
  60 static inline int io_remap_pmd_range(pmd_t * pmd, unsigned long address, unsigned long size,
  61         unsigned long offset, pgprot_t prot, int space)
  62 {
  63         unsigned long end;
  64
  65         address &= ~PGDIR_MASK;
  66         end = address + size;
  67         if (end > PGDIR_SIZE)
  68                 end = PGDIR_SIZE;
  69         offset -= address;
  70         do {
  71                 pte_t * pte = pte_alloc(pmd, address);
  72                 if (!pte)
  73                         return -ENOMEM;
  74                 spin_lock(&current->mm->page_table_lock);
  75                 io_remap_pte_range(pte, address, end - address, address + offset, prot, space);
  76                 spin_unlock(&current->mm->page_table_lock);
  77                 address = (address + PMD_SIZE) & PMD_MASK;
  78                 pmd++;
  79         } while (address < end);
  80         return 0;
  81 }
  82
  83 int io_remap_page_range(unsigned long from, unsigned long offset, unsigned long size, pgprot_t prot, int space)
  84 {
  85         int error = 0;
  86         pgd_t * dir;
  87         unsigned long beg = from;
  88         unsigned long end = from + size;
  89
  90         prot = __pgprot(pg_iobits);
  91         offset -= from;
  92         dir = pgd_offset(current->mm, from);
  93         flush_cache_range(current->mm, beg, end);
  94         while (from < end) {
  95                 pmd_t *pmd = pmd_alloc(dir, from);
  96                 error = -ENOMEM;
  97                 if (!pmd)
  98                         break;
  99                 error = io_remap_pmd_range(pmd, from, end - from, offset + from, prot, space);
 100                 if (error)
 101                         break;
 102                 from = (from + PGDIR_SIZE) & PGDIR_MASK;
 103                 dir++;
 104         }
 105         flush_tlb_range(current->mm, beg, end);
 106         return error;
 107 }