File: /usr/src/linux/arch/sparc/mm/generic.c
1 /* $Id: generic.c,v 1.13 2001/07/17 16:17:33 anton 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 static inline void io_remap_pte_range(pte_t * pte, unsigned long address, unsigned long size,
38 unsigned long offset, pgprot_t prot, int space)
39 {
40 unsigned long end;
41
42 address &= ~PMD_MASK;
43 end = address + size;
44 if (end > PMD_SIZE)
45 end = PMD_SIZE;
46 do {
47 pte_t oldpage = *pte;
48 pte_clear(pte);
49 set_pte(pte, mk_pte_io(offset, prot, space));
50 forget_pte(oldpage);
51 address += PAGE_SIZE;
52 offset += PAGE_SIZE;
53 pte++;
54 } while (address < end);
55 }
56
57 static inline int io_remap_pmd_range(pmd_t * pmd, unsigned long address, unsigned long size,
58 unsigned long offset, pgprot_t prot, int space)
59 {
60 unsigned long end;
61
62 address &= ~PGDIR_MASK;
63 end = address + size;
64 if (end > PGDIR_SIZE)
65 end = PGDIR_SIZE;
66 offset -= address;
67 do {
68 pte_t * pte = pte_alloc(current->mm, pmd, address);
69 if (!pte)
70 return -ENOMEM;
71 io_remap_pte_range(pte, address, end - address, address + offset, prot, space);
72 address = (address + PMD_SIZE) & PMD_MASK;
73 pmd++;
74 } while (address < end);
75 return 0;
76 }
77
78 int io_remap_page_range(unsigned long from, unsigned long offset, unsigned long size, pgprot_t prot, int space)
79 {
80 int error = 0;
81 pgd_t * dir;
82 unsigned long beg = from;
83 unsigned long end = from + size;
84 struct mm_struct *mm = current->mm;
85
86 prot = __pgprot(pg_iobits);
87 offset -= from;
88 dir = pgd_offset(mm, from);
89 flush_cache_range(mm, beg, end);
90
91 spin_lock(&mm->page_table_lock);
92 while (from < end) {
93 pmd_t *pmd = pmd_alloc(current->mm, dir, from);
94 error = -ENOMEM;
95 if (!pmd)
96 break;
97 error = io_remap_pmd_range(pmd, from, end - from, offset + from, prot, space);
98 if (error)
99 break;
100 from = (from + PGDIR_SIZE) & PGDIR_MASK;
101 dir++;
102 }
103 spin_unlock(&mm->page_table_lock);
104
105 flush_tlb_range(current->mm, beg, end);
106 return error;
107 }
108