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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> |
df5419a9 | 10 | #include <linux/personality.h> |
cc92c28b | 11 | #include <linux/random.h> |
41dfaa93 | 12 | #include <asm/cachetype.h> |
1da177e4 LT |
13 | |
14 | #define COLOUR_ALIGN(addr,pgoff) \ | |
15 | ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \ | |
16 | (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1))) | |
17 | ||
7dbaa466 RH |
18 | /* gap between mmap and stack */ |
19 | #define MIN_GAP (128*1024*1024UL) | |
20 | #define MAX_GAP ((TASK_SIZE)/6*5) | |
21 | ||
22 | static int mmap_is_legacy(void) | |
23 | { | |
24 | if (current->personality & ADDR_COMPAT_LAYOUT) | |
25 | return 1; | |
26 | ||
27 | if (rlimit(RLIMIT_STACK) == RLIM_INFINITY) | |
28 | return 1; | |
29 | ||
30 | return sysctl_legacy_va_layout; | |
31 | } | |
32 | ||
33 | static unsigned long mmap_base(unsigned long rnd) | |
34 | { | |
35 | unsigned long gap = rlimit(RLIMIT_STACK); | |
36 | ||
37 | if (gap < MIN_GAP) | |
38 | gap = MIN_GAP; | |
39 | else if (gap > MAX_GAP) | |
40 | gap = MAX_GAP; | |
41 | ||
42 | return PAGE_ALIGN(TASK_SIZE - gap - rnd); | |
43 | } | |
44 | ||
1da177e4 LT |
45 | /* |
46 | * We need to ensure that shared mappings are correctly aligned to | |
47 | * avoid aliasing issues with VIPT caches. We need to ensure that | |
48 | * a specific page of an object is always mapped at a multiple of | |
49 | * SHMLBA bytes. | |
50 | * | |
51 | * We unconditionally provide this function for all cases, however | |
52 | * in the VIVT case, we optimise out the alignment rules. | |
53 | */ | |
54 | unsigned long | |
55 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
56 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
57 | { | |
58 | struct mm_struct *mm = current->mm; | |
59 | struct vm_area_struct *vma; | |
41dfaa93 RH |
60 | int do_align = 0; |
61 | int aliasing = cache_is_vipt_aliasing(); | |
394ef640 | 62 | struct vm_unmapped_area_info info; |
1da177e4 LT |
63 | |
64 | /* | |
65 | * We only need to do colour alignment if either the I or D | |
41dfaa93 | 66 | * caches alias. |
1da177e4 | 67 | */ |
41dfaa93 RH |
68 | if (aliasing) |
69 | do_align = filp || (flags & MAP_SHARED); | |
1da177e4 LT |
70 | |
71 | /* | |
acec0ac0 | 72 | * We enforce the MAP_FIXED case. |
1da177e4 LT |
73 | */ |
74 | if (flags & MAP_FIXED) { | |
e77414e0 AV |
75 | if (aliasing && flags & MAP_SHARED && |
76 | (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) | |
1da177e4 LT |
77 | return -EINVAL; |
78 | return addr; | |
79 | } | |
80 | ||
81 | if (len > TASK_SIZE) | |
82 | return -ENOMEM; | |
83 | ||
84 | if (addr) { | |
85 | if (do_align) | |
86 | addr = COLOUR_ALIGN(addr, pgoff); | |
87 | else | |
88 | addr = PAGE_ALIGN(addr); | |
89 | ||
90 | vma = find_vma(mm, addr); | |
91 | if (TASK_SIZE - len >= addr && | |
92 | (!vma || addr + len <= vma->vm_start)) | |
93 | return addr; | |
94 | } | |
1da177e4 | 95 | |
394ef640 ML |
96 | info.flags = 0; |
97 | info.length = len; | |
98 | info.low_limit = mm->mmap_base; | |
99 | info.high_limit = TASK_SIZE; | |
100 | info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0; | |
101 | info.align_offset = pgoff << PAGE_SHIFT; | |
102 | return vm_unmapped_area(&info); | |
1da177e4 LT |
103 | } |
104 | ||
7dbaa466 RH |
105 | unsigned long |
106 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
107 | const unsigned long len, const unsigned long pgoff, | |
108 | const unsigned long flags) | |
109 | { | |
110 | struct vm_area_struct *vma; | |
111 | struct mm_struct *mm = current->mm; | |
112 | unsigned long addr = addr0; | |
113 | int do_align = 0; | |
114 | int aliasing = cache_is_vipt_aliasing(); | |
394ef640 | 115 | struct vm_unmapped_area_info info; |
7dbaa466 RH |
116 | |
117 | /* | |
118 | * We only need to do colour alignment if either the I or D | |
119 | * caches alias. | |
120 | */ | |
121 | if (aliasing) | |
122 | do_align = filp || (flags & MAP_SHARED); | |
123 | ||
124 | /* requested length too big for entire address space */ | |
125 | if (len > TASK_SIZE) | |
126 | return -ENOMEM; | |
127 | ||
128 | if (flags & MAP_FIXED) { | |
129 | if (aliasing && flags & MAP_SHARED && | |
130 | (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) | |
131 | return -EINVAL; | |
132 | return addr; | |
133 | } | |
134 | ||
135 | /* requesting a specific address */ | |
136 | if (addr) { | |
137 | if (do_align) | |
138 | addr = COLOUR_ALIGN(addr, pgoff); | |
139 | else | |
140 | addr = PAGE_ALIGN(addr); | |
141 | vma = find_vma(mm, addr); | |
142 | if (TASK_SIZE - len >= addr && | |
143 | (!vma || addr + len <= vma->vm_start)) | |
144 | return addr; | |
145 | } | |
146 | ||
394ef640 ML |
147 | info.flags = VM_UNMAPPED_AREA_TOPDOWN; |
148 | info.length = len; | |
149 | info.low_limit = PAGE_SIZE; | |
150 | info.high_limit = mm->mmap_base; | |
151 | info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0; | |
152 | info.align_offset = pgoff << PAGE_SHIFT; | |
153 | addr = vm_unmapped_area(&info); | |
7dbaa466 | 154 | |
7dbaa466 RH |
155 | /* |
156 | * A failed mmap() very likely causes application failure, | |
157 | * so fall back to the bottom-up function here. This scenario | |
158 | * can happen with large stack limits and large mmap() | |
159 | * allocations. | |
160 | */ | |
394ef640 ML |
161 | if (addr & ~PAGE_MASK) { |
162 | VM_BUG_ON(addr != -ENOMEM); | |
163 | info.flags = 0; | |
164 | info.low_limit = mm->mmap_base; | |
165 | info.high_limit = TASK_SIZE; | |
166 | addr = vm_unmapped_area(&info); | |
167 | } | |
7dbaa466 RH |
168 | |
169 | return addr; | |
170 | } | |
171 | ||
172 | void arch_pick_mmap_layout(struct mm_struct *mm) | |
173 | { | |
174 | unsigned long random_factor = 0UL; | |
175 | ||
176 | /* 8 bits of randomness in 20 address space bits */ | |
177 | if ((current->flags & PF_RANDOMIZE) && | |
178 | !(current->personality & ADDR_NO_RANDOMIZE)) | |
179 | random_factor = (get_random_int() % (1 << 8)) << PAGE_SHIFT; | |
180 | ||
181 | if (mmap_is_legacy()) { | |
182 | mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; | |
183 | mm->get_unmapped_area = arch_get_unmapped_area; | |
7dbaa466 RH |
184 | } else { |
185 | mm->mmap_base = mmap_base(random_factor); | |
186 | mm->get_unmapped_area = arch_get_unmapped_area_topdown; | |
7dbaa466 RH |
187 | } |
188 | } | |
51635ad2 LB |
189 | |
190 | /* | |
191 | * You really shouldn't be using read() or write() on /dev/mem. This | |
192 | * might go away in the future. | |
193 | */ | |
7e6735c3 | 194 | int valid_phys_addr_range(phys_addr_t addr, size_t size) |
51635ad2 | 195 | { |
9ae3ae0b AR |
196 | if (addr < PHYS_OFFSET) |
197 | return 0; | |
6806bfe1 | 198 | if (addr + size > __pa(high_memory - 1) + 1) |
51635ad2 LB |
199 | return 0; |
200 | ||
201 | return 1; | |
202 | } | |
203 | ||
204 | /* | |
3159f372 | 205 | * Do not allow /dev/mem mappings beyond the supported physical range. |
51635ad2 LB |
206 | */ |
207 | int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) | |
208 | { | |
3159f372 | 209 | return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT)); |
51635ad2 | 210 | } |
087aaffc NP |
211 | |
212 | #ifdef CONFIG_STRICT_DEVMEM | |
213 | ||
214 | #include <linux/ioport.h> | |
215 | ||
216 | /* | |
217 | * devmem_is_allowed() checks to see if /dev/mem access to a certain | |
218 | * address is valid. The argument is a physical page number. | |
219 | * We mimic x86 here by disallowing access to system RAM as well as | |
220 | * device-exclusive MMIO regions. This effectively disable read()/write() | |
221 | * on /dev/mem. | |
222 | */ | |
223 | int devmem_is_allowed(unsigned long pfn) | |
224 | { | |
225 | if (iomem_is_exclusive(pfn << PAGE_SHIFT)) | |
226 | return 0; | |
227 | if (!page_is_ram(pfn)) | |
228 | return 1; | |
229 | return 0; | |
230 | } | |
231 | ||
232 | #endif |