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Commit | Line | Data |
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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> | |
e8edc6e0 | 8 | #include <linux/sched.h> |
09d9bae0 | 9 | #include <linux/io.h> |
cc92c28b | 10 | #include <linux/random.h> |
0ba8b9b2 | 11 | #include <asm/cputype.h> |
1da177e4 LT |
12 | #include <asm/system.h> |
13 | ||
14 | #define COLOUR_ALIGN(addr,pgoff) \ | |
15 | ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \ | |
16 | (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1))) | |
17 | ||
18 | /* | |
19 | * We need to ensure that shared mappings are correctly aligned to | |
20 | * avoid aliasing issues with VIPT caches. We need to ensure that | |
21 | * a specific page of an object is always mapped at a multiple of | |
22 | * SHMLBA bytes. | |
23 | * | |
24 | * We unconditionally provide this function for all cases, however | |
25 | * in the VIVT case, we optimise out the alignment rules. | |
26 | */ | |
27 | unsigned long | |
28 | 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 | #ifdef CONFIG_CPU_V6 | |
35 | unsigned int cache_type; | |
36 | int do_align = 0, aliasing = 0; | |
37 | ||
38 | /* | |
39 | * We only need to do colour alignment if either the I or D | |
40 | * caches alias. This is indicated by bits 9 and 21 of the | |
41 | * cache type register. | |
42 | */ | |
0ba8b9b2 RK |
43 | cache_type = read_cpuid_cachetype(); |
44 | if (cache_type != read_cpuid_id()) { | |
1da177e4 LT |
45 | aliasing = (cache_type | cache_type >> 12) & (1 << 11); |
46 | if (aliasing) | |
47 | do_align = filp || flags & MAP_SHARED; | |
48 | } | |
49 | #else | |
50 | #define do_align 0 | |
51 | #define aliasing 0 | |
52 | #endif | |
53 | ||
54 | /* | |
acec0ac0 | 55 | * We enforce the MAP_FIXED case. |
1da177e4 LT |
56 | */ |
57 | if (flags & MAP_FIXED) { | |
e77414e0 AV |
58 | if (aliasing && flags & MAP_SHARED && |
59 | (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) | |
1da177e4 LT |
60 | return -EINVAL; |
61 | return addr; | |
62 | } | |
63 | ||
64 | if (len > TASK_SIZE) | |
65 | return -ENOMEM; | |
66 | ||
67 | if (addr) { | |
68 | if (do_align) | |
69 | addr = COLOUR_ALIGN(addr, pgoff); | |
70 | else | |
71 | addr = PAGE_ALIGN(addr); | |
72 | ||
73 | vma = find_vma(mm, addr); | |
74 | if (TASK_SIZE - len >= addr && | |
75 | (!vma || addr + len <= vma->vm_start)) | |
76 | return addr; | |
77 | } | |
1363c3cd WW |
78 | if (len > mm->cached_hole_size) { |
79 | start_addr = addr = mm->free_area_cache; | |
80 | } else { | |
81 | start_addr = addr = TASK_UNMAPPED_BASE; | |
82 | mm->cached_hole_size = 0; | |
83 | } | |
cc92c28b NP |
84 | /* 8 bits of randomness in 20 address space bits */ |
85 | if (current->flags & PF_RANDOMIZE) | |
86 | addr += (get_random_int() % (1 << 8)) << PAGE_SHIFT; | |
1da177e4 LT |
87 | |
88 | full_search: | |
89 | if (do_align) | |
90 | addr = COLOUR_ALIGN(addr, pgoff); | |
91 | else | |
92 | addr = PAGE_ALIGN(addr); | |
93 | ||
94 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { | |
95 | /* At this point: (!vma || addr < vma->vm_end). */ | |
96 | if (TASK_SIZE - len < addr) { | |
97 | /* | |
98 | * Start a new search - just in case we missed | |
99 | * some holes. | |
100 | */ | |
101 | if (start_addr != TASK_UNMAPPED_BASE) { | |
102 | start_addr = addr = TASK_UNMAPPED_BASE; | |
1363c3cd | 103 | mm->cached_hole_size = 0; |
1da177e4 LT |
104 | goto full_search; |
105 | } | |
106 | return -ENOMEM; | |
107 | } | |
108 | if (!vma || addr + len <= vma->vm_start) { | |
109 | /* | |
110 | * Remember the place where we stopped the search: | |
111 | */ | |
112 | mm->free_area_cache = addr + len; | |
113 | return addr; | |
114 | } | |
1363c3cd WW |
115 | if (addr + mm->cached_hole_size < vma->vm_start) |
116 | mm->cached_hole_size = vma->vm_start - addr; | |
1da177e4 LT |
117 | addr = vma->vm_end; |
118 | if (do_align) | |
119 | addr = COLOUR_ALIGN(addr, pgoff); | |
120 | } | |
121 | } | |
122 | ||
51635ad2 LB |
123 | |
124 | /* | |
125 | * You really shouldn't be using read() or write() on /dev/mem. This | |
126 | * might go away in the future. | |
127 | */ | |
128 | int valid_phys_addr_range(unsigned long addr, size_t size) | |
129 | { | |
9ae3ae0b AR |
130 | if (addr < PHYS_OFFSET) |
131 | return 0; | |
6806bfe1 | 132 | if (addr + size > __pa(high_memory - 1) + 1) |
51635ad2 LB |
133 | return 0; |
134 | ||
135 | return 1; | |
136 | } | |
137 | ||
138 | /* | |
139 | * We don't use supersection mappings for mmap() on /dev/mem, which | |
140 | * means that we can't map the memory area above the 4G barrier into | |
141 | * userspace. | |
142 | */ | |
143 | int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) | |
144 | { | |
145 | return !(pfn + (size >> PAGE_SHIFT) > 0x00100000); | |
146 | } | |
087aaffc NP |
147 | |
148 | #ifdef CONFIG_STRICT_DEVMEM | |
149 | ||
150 | #include <linux/ioport.h> | |
151 | ||
152 | /* | |
153 | * devmem_is_allowed() checks to see if /dev/mem access to a certain | |
154 | * address is valid. The argument is a physical page number. | |
155 | * We mimic x86 here by disallowing access to system RAM as well as | |
156 | * device-exclusive MMIO regions. This effectively disable read()/write() | |
157 | * on /dev/mem. | |
158 | */ | |
159 | int devmem_is_allowed(unsigned long pfn) | |
160 | { | |
161 | if (iomem_is_exclusive(pfn << PAGE_SHIFT)) | |
162 | return 0; | |
163 | if (!page_is_ram(pfn)) | |
164 | return 1; | |
165 | return 0; | |
166 | } | |
167 | ||
168 | #endif |