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1da177e4 LT |
1 | /* |
2 | * linux/arch/arm/mm/mmap.c | |
3 | */ | |
1da177e4 LT |
4 | #include <linux/fs.h> |
5 | #include <linux/mm.h> | |
6 | #include <linux/mman.h> | |
7 | #include <linux/shm.h> | |
8 | ||
9 | #include <asm/system.h> | |
10 | ||
11 | #define COLOUR_ALIGN(addr,pgoff) \ | |
12 | ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \ | |
13 | (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1))) | |
14 | ||
15 | /* | |
16 | * We need to ensure that shared mappings are correctly aligned to | |
17 | * avoid aliasing issues with VIPT caches. We need to ensure that | |
18 | * a specific page of an object is always mapped at a multiple of | |
19 | * SHMLBA bytes. | |
20 | * | |
21 | * We unconditionally provide this function for all cases, however | |
22 | * in the VIVT case, we optimise out the alignment rules. | |
23 | */ | |
24 | unsigned long | |
25 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
26 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
27 | { | |
28 | struct mm_struct *mm = current->mm; | |
29 | struct vm_area_struct *vma; | |
30 | unsigned long start_addr; | |
31 | #ifdef CONFIG_CPU_V6 | |
32 | unsigned int cache_type; | |
33 | int do_align = 0, aliasing = 0; | |
34 | ||
35 | /* | |
36 | * We only need to do colour alignment if either the I or D | |
37 | * caches alias. This is indicated by bits 9 and 21 of the | |
38 | * cache type register. | |
39 | */ | |
40 | cache_type = read_cpuid(CPUID_CACHETYPE); | |
41 | if (cache_type != read_cpuid(CPUID_ID)) { | |
42 | aliasing = (cache_type | cache_type >> 12) & (1 << 11); | |
43 | if (aliasing) | |
44 | do_align = filp || flags & MAP_SHARED; | |
45 | } | |
46 | #else | |
47 | #define do_align 0 | |
48 | #define aliasing 0 | |
49 | #endif | |
50 | ||
51 | /* | |
acec0ac0 | 52 | * We enforce the MAP_FIXED case. |
1da177e4 LT |
53 | */ |
54 | if (flags & MAP_FIXED) { | |
55 | if (aliasing && flags & MAP_SHARED && addr & (SHMLBA - 1)) | |
56 | return -EINVAL; | |
57 | return addr; | |
58 | } | |
59 | ||
60 | if (len > TASK_SIZE) | |
61 | return -ENOMEM; | |
62 | ||
63 | if (addr) { | |
64 | if (do_align) | |
65 | addr = COLOUR_ALIGN(addr, pgoff); | |
66 | else | |
67 | addr = PAGE_ALIGN(addr); | |
68 | ||
69 | vma = find_vma(mm, addr); | |
70 | if (TASK_SIZE - len >= addr && | |
71 | (!vma || addr + len <= vma->vm_start)) | |
72 | return addr; | |
73 | } | |
1363c3cd WW |
74 | if (len > mm->cached_hole_size) { |
75 | start_addr = addr = mm->free_area_cache; | |
76 | } else { | |
77 | start_addr = addr = TASK_UNMAPPED_BASE; | |
78 | mm->cached_hole_size = 0; | |
79 | } | |
1da177e4 LT |
80 | |
81 | full_search: | |
82 | if (do_align) | |
83 | addr = COLOUR_ALIGN(addr, pgoff); | |
84 | else | |
85 | addr = PAGE_ALIGN(addr); | |
86 | ||
87 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { | |
88 | /* At this point: (!vma || addr < vma->vm_end). */ | |
89 | if (TASK_SIZE - len < addr) { | |
90 | /* | |
91 | * Start a new search - just in case we missed | |
92 | * some holes. | |
93 | */ | |
94 | if (start_addr != TASK_UNMAPPED_BASE) { | |
95 | start_addr = addr = TASK_UNMAPPED_BASE; | |
1363c3cd | 96 | mm->cached_hole_size = 0; |
1da177e4 LT |
97 | goto full_search; |
98 | } | |
99 | return -ENOMEM; | |
100 | } | |
101 | if (!vma || addr + len <= vma->vm_start) { | |
102 | /* | |
103 | * Remember the place where we stopped the search: | |
104 | */ | |
105 | mm->free_area_cache = addr + len; | |
106 | return addr; | |
107 | } | |
1363c3cd WW |
108 | if (addr + mm->cached_hole_size < vma->vm_start) |
109 | mm->cached_hole_size = vma->vm_start - addr; | |
1da177e4 LT |
110 | addr = vma->vm_end; |
111 | if (do_align) | |
112 | addr = COLOUR_ALIGN(addr, pgoff); | |
113 | } | |
114 | } | |
115 | ||
51635ad2 LB |
116 | |
117 | /* | |
118 | * You really shouldn't be using read() or write() on /dev/mem. This | |
119 | * might go away in the future. | |
120 | */ | |
121 | int valid_phys_addr_range(unsigned long addr, size_t size) | |
122 | { | |
123 | if (addr + size > __pa(high_memory)) | |
124 | return 0; | |
125 | ||
126 | return 1; | |
127 | } | |
128 | ||
129 | /* | |
130 | * We don't use supersection mappings for mmap() on /dev/mem, which | |
131 | * means that we can't map the memory area above the 4G barrier into | |
132 | * userspace. | |
133 | */ | |
134 | int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) | |
135 | { | |
136 | return !(pfn + (size >> PAGE_SHIFT) > 0x00100000); | |
137 | } |