Merge branch 'sh/for-2.6.29' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal...
[linux-2.6] / arch / sh / mm / mmap.c
1 /*
2  * arch/sh/mm/mmap.c
3  *
4  * Copyright (C) 2008  Paul Mundt
5  *
6  * This file is subject to the terms and conditions of the GNU General Public
7  * License.  See the file "COPYING" in the main directory of this archive
8  * for more details.
9  */
10 #include <linux/io.h>
11 #include <linux/mm.h>
12 #include <linux/mman.h>
13 #include <linux/module.h>
14 #include <asm/page.h>
15 #include <asm/processor.h>
16
17 #ifdef CONFIG_MMU
18 unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */
19 EXPORT_SYMBOL(shm_align_mask);
20
21 /*
22  * To avoid cache aliases, we map the shared page with same color.
23  */
24 #define COLOUR_ALIGN(addr, pgoff)                               \
25         ((((addr) + shm_align_mask) & ~shm_align_mask) +        \
26          (((pgoff) << PAGE_SHIFT) & shm_align_mask))
27
28 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
29         unsigned long len, unsigned long pgoff, unsigned long flags)
30 {
31         struct mm_struct *mm = current->mm;
32         struct vm_area_struct *vma;
33         unsigned long start_addr;
34         int do_colour_align;
35
36         if (flags & MAP_FIXED) {
37                 /* We do not accept a shared mapping if it would violate
38                  * cache aliasing constraints.
39                  */
40                 if ((flags & MAP_SHARED) && (addr & shm_align_mask))
41                         return -EINVAL;
42                 return addr;
43         }
44
45         if (unlikely(len > TASK_SIZE))
46                 return -ENOMEM;
47
48         do_colour_align = 0;
49         if (filp || (flags & MAP_SHARED))
50                 do_colour_align = 1;
51
52         if (addr) {
53                 if (do_colour_align)
54                         addr = COLOUR_ALIGN(addr, pgoff);
55                 else
56                         addr = PAGE_ALIGN(addr);
57
58                 vma = find_vma(mm, addr);
59                 if (TASK_SIZE - len >= addr &&
60                     (!vma || addr + len <= vma->vm_start))
61                         return addr;
62         }
63
64         if (len > mm->cached_hole_size) {
65                 start_addr = addr = mm->free_area_cache;
66         } else {
67                 mm->cached_hole_size = 0;
68                 start_addr = addr = TASK_UNMAPPED_BASE;
69         }
70
71 full_search:
72         if (do_colour_align)
73                 addr = COLOUR_ALIGN(addr, pgoff);
74         else
75                 addr = PAGE_ALIGN(mm->free_area_cache);
76
77         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
78                 /* At this point:  (!vma || addr < vma->vm_end). */
79                 if (unlikely(TASK_SIZE - len < addr)) {
80                         /*
81                          * Start a new search - just in case we missed
82                          * some holes.
83                          */
84                         if (start_addr != TASK_UNMAPPED_BASE) {
85                                 start_addr = addr = TASK_UNMAPPED_BASE;
86                                 mm->cached_hole_size = 0;
87                                 goto full_search;
88                         }
89                         return -ENOMEM;
90                 }
91                 if (likely(!vma || addr + len <= vma->vm_start)) {
92                         /*
93                          * Remember the place where we stopped the search:
94                          */
95                         mm->free_area_cache = addr + len;
96                         return addr;
97                 }
98                 if (addr + mm->cached_hole_size < vma->vm_start)
99                         mm->cached_hole_size = vma->vm_start - addr;
100
101                 addr = vma->vm_end;
102                 if (do_colour_align)
103                         addr = COLOUR_ALIGN(addr, pgoff);
104         }
105 }
106 #endif /* CONFIG_MMU */
107
108 /*
109  * You really shouldn't be using read() or write() on /dev/mem.  This
110  * might go away in the future.
111  */
112 int valid_phys_addr_range(unsigned long addr, size_t count)
113 {
114         if (addr < __MEMORY_START)
115                 return 0;
116         if (addr + count > __pa(high_memory))
117                 return 0;
118
119         return 1;
120 }
121
122 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
123 {
124         return 1;
125 }