arch/sparc64/mm/generic.c

   1 /* $Id: generic.c,v 1.18 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/tlbflush.h>
  17
  18 static inline void forget_pte(pte_t page)
  19 {
  20         if (!pte_none(page)) {
  21                 printk("forget_pte: old mapping existed!\n");
  22                 BUG();
  23         }
  24 }
  25
  26 /* Remap IO memory, the same way as remap_page_range(), but use
  27  * the obio memory space.
  28  *
  29  * They use a pgprot that sets PAGE_IO and does not check the
  30  * mem_map table as this is independent of normal memory.
  31  *
  32  * As a special hack if the lowest bit of offset is set the
  33  * side-effect bit will be turned off.  This is used as a
  34  * performance improvement on FFB/AFB. -DaveM
  35  */
  36 static inline void io_remap_pte_range(pte_t * pte, unsigned long address, unsigned long size,
  37         unsigned long offset, pgprot_t prot, int space)
  38 {
  39         unsigned long end;
  40
  41         address &= ~PMD_MASK;
  42         end = address + size;
  43         if (end > PMD_SIZE)
  44                 end = PMD_SIZE;
  45         do {
  46                 pte_t oldpage;
  47                 pte_t entry;
  48                 unsigned long curend = address + PAGE_SIZE;
  49
  50                 entry = mk_pte_io((offset & ~(0x1UL)), prot, space);
  51                 if (!(address & 0xffff)) {
  52                         if (!(address & 0x3fffff) && !(offset & 0x3ffffe) && end >= address + 0x400000) {
  53                                 entry = mk_pte_io((offset & ~(0x1UL)),
  54                                                   __pgprot(pgprot_val (prot) | _PAGE_SZ4MB),
  55                                                   space);
  56                                 curend = address + 0x400000;
  57                                 offset += 0x400000;
  58                         } else if (!(address & 0x7ffff) && !(offset & 0x7fffe) && end >= address + 0x80000) {
  59                                 entry = mk_pte_io((offset & ~(0x1UL)),
  60                                                   __pgprot(pgprot_val (prot) | _PAGE_SZ512K),
  61                                                   space);
  62                                 curend = address + 0x80000;
  63                                 offset += 0x80000;
  64                         } else if (!(offset & 0xfffe) && end >= address + 0x10000) {
  65                                 entry = mk_pte_io((offset & ~(0x1UL)),
  66                                                   __pgprot(pgprot_val (prot) | _PAGE_SZ64K),
  67                                                   space);
  68                                 curend = address + 0x10000;
  69                                 offset += 0x10000;
  70                         } else
  71                                 offset += PAGE_SIZE;
  72                 } else
  73                         offset += PAGE_SIZE;
  74
  75                 if (offset & 0x1UL)
  76                         pte_val(entry) &= ~(_PAGE_E);
  77                 do {
  78                         oldpage = *pte;
  79                         pte_clear(pte);
  80                         set_pte(pte, entry);
  81                         forget_pte(oldpage);
  82                         address += PAGE_SIZE;
  83                         pte++;
  84                 } while (address < curend);
  85         } while (address < end);
  86 }
  87
  88 static inline int io_remap_pmd_range(pmd_t * pmd, unsigned long address, unsigned long size,
  89         unsigned long offset, pgprot_t prot, int space)
  90 {
  91         unsigned long end;
  92
  93         address &= ~PGDIR_MASK;
  94         end = address + size;
  95         if (end > PGDIR_SIZE)
  96                 end = PGDIR_SIZE;
  97         offset -= address;
  98         do {
  99                 pte_t * pte = pte_alloc_map(current->mm, pmd, address);
 100                 if (!pte)
 101                         return -ENOMEM;
 102                 io_remap_pte_range(pte, address, end - address, address + offset, prot, space);
 103                 pte_unmap(pte);
 104                 address = (address + PMD_SIZE) & PMD_MASK;
 105                 pmd++;
 106         } while (address < end);
 107         return 0;
 108 }
 109
 110 int io_remap_page_range(struct vm_area_struct *vma, unsigned long from, unsigned long offset, unsigned long size, pgprot_t prot, int space)
 111 {
 112         int error = 0;
 113         pgd_t * dir;
 114         unsigned long beg = from;
 115         unsigned long end = from + size;
 116         struct mm_struct *mm = vma->vm_mm;
 117
 118         prot = __pgprot(pg_iobits);
 119         offset -= from;
 120         dir = pgd_offset(mm, from);
 121         flush_cache_range(vma, beg, end);
 122
 123         spin_lock(&mm->page_table_lock);
 124         while (from < end) {
 125                 pmd_t *pmd = pmd_alloc(current->mm, dir, from);
 126                 error = -ENOMEM;
 127                 if (!pmd)
 128                         break;
 129                 error = io_remap_pmd_range(pmd, from, end - from, offset + from, prot, space);
 130                 if (error)
 131                         break;
 132                 from = (from + PGDIR_SIZE) & PGDIR_MASK;
 133                 dir++;
 134         }
 135         spin_unlock(&mm->page_table_lock);
 136
 137         flush_tlb_range(vma, beg, end);
 138         return error;
 139 }