[ARM] Fix virtual to physical translation macro corner cases
[linux-2.6.git] / arch / arm / mm / mmap.c
1 /*
2  *  linux/arch/arm/mm/mmap.c
3  */
4 #include <linux/fs.h>
5 #include <linux/mm.h>
6 #include <linux/mman.h>
7 #include <linux/shm.h>
8 #include <linux/sched.h>
9 #include <linux/io.h>
10 #include <asm/cputype.h>
11 #include <asm/system.h>
12
13 #define COLOUR_ALIGN(addr,pgoff)                \
14         ((((addr)+SHMLBA-1)&~(SHMLBA-1)) +      \
15          (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
16
17 /*
18  * We need to ensure that shared mappings are correctly aligned to
19  * avoid aliasing issues with VIPT caches.  We need to ensure that
20  * a specific page of an object is always mapped at a multiple of
21  * SHMLBA bytes.
22  *
23  * We unconditionally provide this function for all cases, however
24  * in the VIVT case, we optimise out the alignment rules.
25  */
26 unsigned long
27 arch_get_unmapped_area(struct file *filp, unsigned long addr,
28                 unsigned long len, unsigned long pgoff, unsigned long flags)
29 {
30         struct mm_struct *mm = current->mm;
31         struct vm_area_struct *vma;
32         unsigned long start_addr;
33 #ifdef CONFIG_CPU_V6
34         unsigned int cache_type;
35         int do_align = 0, aliasing = 0;
36
37         /*
38          * We only need to do colour alignment if either the I or D
39          * caches alias.  This is indicated by bits 9 and 21 of the
40          * cache type register.
41          */
42         cache_type = read_cpuid_cachetype();
43         if (cache_type != read_cpuid_id()) {
44                 aliasing = (cache_type | cache_type >> 12) & (1 << 11);
45                 if (aliasing)
46                         do_align = filp || flags & MAP_SHARED;
47         }
48 #else
49 #define do_align 0
50 #define aliasing 0
51 #endif
52
53         /*
54          * We enforce the MAP_FIXED case.
55          */
56         if (flags & MAP_FIXED) {
57                 if (aliasing && flags & MAP_SHARED && addr & (SHMLBA - 1))
58                         return -EINVAL;
59                 return addr;
60         }
61
62         if (len > TASK_SIZE)
63                 return -ENOMEM;
64
65         if (addr) {
66                 if (do_align)
67                         addr = COLOUR_ALIGN(addr, pgoff);
68                 else
69                         addr = PAGE_ALIGN(addr);
70
71                 vma = find_vma(mm, addr);
72                 if (TASK_SIZE - len >= addr &&
73                     (!vma || addr + len <= vma->vm_start))
74                         return addr;
75         }
76         if (len > mm->cached_hole_size) {
77                 start_addr = addr = mm->free_area_cache;
78         } else {
79                 start_addr = addr = TASK_UNMAPPED_BASE;
80                 mm->cached_hole_size = 0;
81         }
82
83 full_search:
84         if (do_align)
85                 addr = COLOUR_ALIGN(addr, pgoff);
86         else
87                 addr = PAGE_ALIGN(addr);
88
89         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
90                 /* At this point:  (!vma || addr < vma->vm_end). */
91                 if (TASK_SIZE - len < addr) {
92                         /*
93                          * Start a new search - just in case we missed
94                          * some holes.
95                          */
96                         if (start_addr != TASK_UNMAPPED_BASE) {
97                                 start_addr = addr = TASK_UNMAPPED_BASE;
98                                 mm->cached_hole_size = 0;
99                                 goto full_search;
100                         }
101                         return -ENOMEM;
102                 }
103                 if (!vma || addr + len <= vma->vm_start) {
104                         /*
105                          * Remember the place where we stopped the search:
106                          */
107                         mm->free_area_cache = addr + len;
108                         return addr;
109                 }
110                 if (addr + mm->cached_hole_size < vma->vm_start)
111                         mm->cached_hole_size = vma->vm_start - addr;
112                 addr = vma->vm_end;
113                 if (do_align)
114                         addr = COLOUR_ALIGN(addr, pgoff);
115         }
116 }
117
118
119 /*
120  * You really shouldn't be using read() or write() on /dev/mem.  This
121  * might go away in the future.
122  */
123 int valid_phys_addr_range(unsigned long addr, size_t size)
124 {
125         if (addr < PHYS_OFFSET)
126                 return 0;
127         if (addr + size >= __pa(high_memory - 1))
128                 return 0;
129
130         return 1;
131 }
132
133 /*
134  * We don't use supersection mappings for mmap() on /dev/mem, which
135  * means that we can't map the memory area above the 4G barrier into
136  * userspace.
137  */
138 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
139 {
140         return !(pfn + (size >> PAGE_SHIFT) > 0x00100000);
141 }