arch/sparc64/mm/generic.c

   1 /* $Id: generic.c,v 1.13 1999/12/20 05:02:33 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                 unsigned long nr = pte_pagenr(page);
  22                 if (nr >= max_mapnr || PageReserved(mem_map+nr))
  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(mem_map+nr);
  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  * As a special hack if the lowest bit of offset is set the
  41  * side-effect bit will be turned off.  This is used as a
  42  * performance improvement on FFB/AFB. -DaveM
  43  */
  44 static inline void io_remap_pte_range(pte_t * pte, unsigned long address, unsigned long size,
  45         unsigned long offset, pgprot_t prot, int space)
  46 {
  47         unsigned long end;
  48
  49         address &= ~PMD_MASK;
  50         end = address + size;
  51         if (end > PMD_SIZE)
  52                 end = PMD_SIZE;
  53         do {
  54                 pte_t oldpage;
  55                 pte_t entry;
  56                 unsigned long curend = address + PAGE_SIZE;
  57
  58                 entry = mk_pte_io((offset & ~(0x1UL)), prot, space);
  59                 if (!(address & 0xffff)) {
  60                         if (!(address & 0x3fffff) && !(offset & 0x3ffffe) && end >= address + 0x400000) {
  61                                 entry = mk_pte_io((offset & ~(0x1UL)),
  62                                                   __pgprot(pgprot_val (prot) | _PAGE_SZ4MB),
  63                                                   space);
  64                                 curend = address + 0x400000;
  65                                 offset += 0x400000;
  66                         } else if (!(address & 0x7ffff) && !(offset & 0x7fffe) && end >= address + 0x80000) {
  67                                 entry = mk_pte_io((offset & ~(0x1UL)),
  68                                                   __pgprot(pgprot_val (prot) | _PAGE_SZ512K),
  69                                                   space);
  70                                 curend = address + 0x80000;
  71                                 offset += 0x80000;
  72                         } else if (!(offset & 0xfffe) && end >= address + 0x10000) {
  73                                 entry = mk_pte_io((offset & ~(0x1UL)),
  74                                                   __pgprot(pgprot_val (prot) | _PAGE_SZ64K),
  75                                                   space);
  76                                 curend = address + 0x10000;
  77                                 offset += 0x10000;
  78                         } else
  79                                 offset += PAGE_SIZE;
  80                 } else
  81                         offset += PAGE_SIZE;
  82
  83                 if (offset & 0x1UL)
  84                         pte_val(entry) &= ~(_PAGE_E);
  85                 do {
  86                         oldpage = *pte;
  87                         pte_clear(pte);
  88                         set_pte(pte, entry);
  89                         forget_pte(oldpage);
  90                         address += PAGE_SIZE;
  91                         pte++;
  92                 } while (address < curend);
  93         } while (address < end);
  94 }
  95
  96 static inline int io_remap_pmd_range(pmd_t * pmd, unsigned long address, unsigned long size,
  97         unsigned long offset, pgprot_t prot, int space)
  98 {
  99         unsigned long end;
 100
 101         address &= ~PGDIR_MASK;
 102         end = address + size;
 103         if (end > PGDIR_SIZE)
 104                 end = PGDIR_SIZE;
 105         offset -= address;
 106         do {
 107                 pte_t * pte = pte_alloc(pmd, address);
 108                 if (!pte)
 109                         return -ENOMEM;
 110                 spin_lock(&current->mm->page_table_lock);
 111                 io_remap_pte_range(pte, address, end - address, address + offset, prot, space);
 112                 spin_unlock(&current->mm->page_table_lock);
 113                 address = (address + PMD_SIZE) & PMD_MASK;
 114                 pmd++;
 115         } while (address < end);
 116         return 0;
 117 }
 118
 119 int io_remap_page_range(unsigned long from, unsigned long offset, unsigned long size, pgprot_t prot, int space)
 120 {
 121         int error = 0;
 122         pgd_t * dir;
 123         unsigned long beg = from;
 124         unsigned long end = from + size;
 125
 126         prot = __pgprot(pg_iobits);
 127         offset -= from;
 128         dir = pgd_offset(current->mm, from);
 129         flush_cache_range(current->mm, beg, end);
 130         while (from < end) {
 131                 pmd_t *pmd = pmd_alloc(dir, from);
 132                 error = -ENOMEM;
 133                 if (!pmd)
 134                         break;
 135                 error = io_remap_pmd_range(pmd, from, end - from, offset + from, prot, space);
 136                 if (error)
 137                         break;
 138                 from = (from + PGDIR_SIZE) & PGDIR_MASK;
 139                 dir++;
 140         }
 141         flush_tlb_range(current->mm, beg, end);
 142         return error;
 143 }