arch/sparc64/mm/generic.c

   1 /* $Id: generic.c,v 1.17 2001/04/09 04:08:06 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
  17 static inline void forget_pte(pte_t page)
  18 {
  19         if (pte_none(page))
  20                 return;
  21         if (pte_present(page)) {
  22                 struct page *ptpage = pte_page(page);
  23                 if ((!VALID_PAGE(ptpage)) || PageReserved(ptpage))
  24                         return;
  25                 page_cache_release(ptpage);
  26                 return;
  27         }
  28         swap_free(pte_to_swp_entry(page));
  29 }
  30
  31 /* Remap IO memory, the same way as remap_page_range(), but use
  32  * the obio memory space.
  33  *
  34  * They use a pgprot that sets PAGE_IO and does not check the
  35  * mem_map table as this is independent of normal memory.
  36  *
  37  * As a special hack if the lowest bit of offset is set the
  38  * side-effect bit will be turned off.  This is used as a
  39  * performance improvement on FFB/AFB. -DaveM
  40  */
  41 static inline void io_remap_pte_range(pte_t * pte, unsigned long address, unsigned long size,
  42         unsigned long offset, pgprot_t prot, int space)
  43 {
  44         unsigned long end;
  45
  46         address &= ~PMD_MASK;
  47         end = address + size;
  48         if (end > PMD_SIZE)
  49                 end = PMD_SIZE;
  50         do {
  51                 pte_t oldpage;
  52                 pte_t entry;
  53                 unsigned long curend = address + PAGE_SIZE;
  54
  55                 entry = mk_pte_io((offset & ~(0x1UL)), prot, space);
  56                 if (!(address & 0xffff)) {
  57                         if (!(address & 0x3fffff) && !(offset & 0x3ffffe) && end >= address + 0x400000) {
  58                                 entry = mk_pte_io((offset & ~(0x1UL)),
  59                                                   __pgprot(pgprot_val (prot) | _PAGE_SZ4MB),
  60                                                   space);
  61                                 curend = address + 0x400000;
  62                                 offset += 0x400000;
  63                         } else if (!(address & 0x7ffff) && !(offset & 0x7fffe) && end >= address + 0x80000) {
  64                                 entry = mk_pte_io((offset & ~(0x1UL)),
  65                                                   __pgprot(pgprot_val (prot) | _PAGE_SZ512K),
  66                                                   space);
  67                                 curend = address + 0x80000;
  68                                 offset += 0x80000;
  69                         } else if (!(offset & 0xfffe) && end >= address + 0x10000) {
  70                                 entry = mk_pte_io((offset & ~(0x1UL)),
  71                                                   __pgprot(pgprot_val (prot) | _PAGE_SZ64K),
  72                                                   space);
  73                                 curend = address + 0x10000;
  74                                 offset += 0x10000;
  75                         } else
  76                                 offset += PAGE_SIZE;
  77                 } else
  78                         offset += PAGE_SIZE;
  79
  80                 if (offset & 0x1UL)
  81                         pte_val(entry) &= ~(_PAGE_E);
  82                 do {
  83                         oldpage = *pte;
  84                         pte_clear(pte);
  85                         set_pte(pte, entry);
  86                         forget_pte(oldpage);
  87                         address += PAGE_SIZE;
  88                         pte++;
  89                 } while (address < curend);
  90         } while (address < end);
  91 }
  92
  93 static inline int io_remap_pmd_range(pmd_t * pmd, unsigned long address, unsigned long size,
  94         unsigned long offset, pgprot_t prot, int space)
  95 {
  96         unsigned long end;
  97
  98         address &= ~PGDIR_MASK;
  99         end = address + size;
 100         if (end > PGDIR_SIZE)
 101                 end = PGDIR_SIZE;
 102         offset -= address;
 103         do {
 104                 pte_t * pte = pte_alloc(current->mm, pmd, address);
 105                 if (!pte)
 106                         return -ENOMEM;
 107                 io_remap_pte_range(pte, address, end - address, address + offset, prot, space);
 108                 address = (address + PMD_SIZE) & PMD_MASK;
 109                 pmd++;
 110         } while (address < end);
 111         return 0;
 112 }
 113
 114 int io_remap_page_range(unsigned long from, unsigned long offset, unsigned long size, pgprot_t prot, int space)
 115 {
 116         int error = 0;
 117         pgd_t * dir;
 118         unsigned long beg = from;
 119         unsigned long end = from + size;
 120         struct mm_struct *mm = current->mm;
 121
 122         prot = __pgprot(pg_iobits);
 123         offset -= from;
 124         dir = pgd_offset(mm, from);
 125         flush_cache_range(mm, beg, end);
 126
 127         spin_lock(&mm->page_table_lock);
 128         while (from < end) {
 129                 pmd_t *pmd = pmd_alloc(current->mm, dir, from);
 130                 error = -ENOMEM;
 131                 if (!pmd)
 132                         break;
 133                 error = io_remap_pmd_range(pmd, from, end - from, offset + from, prot, space);
 134                 if (error)
 135                         break;
 136                 from = (from + PGDIR_SIZE) & PGDIR_MASK;
 137                 dir++;
 138         }
 139         spin_unlock(&mm->page_table_lock);
 140
 141         flush_tlb_range(current->mm, beg, end);
 142         return error;
 143 }