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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 | 13 | |
7dbaa466 RH |
14 | static inline unsigned long COLOUR_ALIGN_DOWN(unsigned long addr, |
15 | unsigned long pgoff) | |
16 | { | |
17 | unsigned long base = addr & ~(SHMLBA-1); | |
18 | unsigned long off = (pgoff << PAGE_SHIFT) & (SHMLBA-1); | |
19 | ||
20 | if (base + off <= addr) | |
21 | return base + off; | |
22 | ||
23 | return base - off; | |
24 | } | |
25 | ||
1da177e4 LT |
26 | #define COLOUR_ALIGN(addr,pgoff) \ |
27 | ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \ | |
28 | (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1))) | |
29 | ||
7dbaa466 RH |
30 | /* gap between mmap and stack */ |
31 | #define MIN_GAP (128*1024*1024UL) | |
32 | #define MAX_GAP ((TASK_SIZE)/6*5) | |
33 | ||
34 | static int mmap_is_legacy(void) | |
35 | { | |
36 | if (current->personality & ADDR_COMPAT_LAYOUT) | |
37 | return 1; | |
38 | ||
39 | if (rlimit(RLIMIT_STACK) == RLIM_INFINITY) | |
40 | return 1; | |
41 | ||
42 | return sysctl_legacy_va_layout; | |
43 | } | |
44 | ||
45 | static unsigned long mmap_base(unsigned long rnd) | |
46 | { | |
47 | unsigned long gap = rlimit(RLIMIT_STACK); | |
48 | ||
49 | if (gap < MIN_GAP) | |
50 | gap = MIN_GAP; | |
51 | else if (gap > MAX_GAP) | |
52 | gap = MAX_GAP; | |
53 | ||
54 | return PAGE_ALIGN(TASK_SIZE - gap - rnd); | |
55 | } | |
56 | ||
1da177e4 LT |
57 | /* |
58 | * We need to ensure that shared mappings are correctly aligned to | |
59 | * avoid aliasing issues with VIPT caches. We need to ensure that | |
60 | * a specific page of an object is always mapped at a multiple of | |
61 | * SHMLBA bytes. | |
62 | * | |
63 | * We unconditionally provide this function for all cases, however | |
64 | * in the VIVT case, we optimise out the alignment rules. | |
65 | */ | |
66 | unsigned long | |
67 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
68 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
69 | { | |
70 | struct mm_struct *mm = current->mm; | |
71 | struct vm_area_struct *vma; | |
72 | unsigned long start_addr; | |
41dfaa93 RH |
73 | int do_align = 0; |
74 | int aliasing = cache_is_vipt_aliasing(); | |
1da177e4 LT |
75 | |
76 | /* | |
77 | * We only need to do colour alignment if either the I or D | |
41dfaa93 | 78 | * caches alias. |
1da177e4 | 79 | */ |
41dfaa93 RH |
80 | if (aliasing) |
81 | do_align = filp || (flags & MAP_SHARED); | |
1da177e4 LT |
82 | |
83 | /* | |
acec0ac0 | 84 | * We enforce the MAP_FIXED case. |
1da177e4 LT |
85 | */ |
86 | if (flags & MAP_FIXED) { | |
e77414e0 AV |
87 | if (aliasing && flags & MAP_SHARED && |
88 | (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) | |
1da177e4 LT |
89 | return -EINVAL; |
90 | return addr; | |
91 | } | |
92 | ||
93 | if (len > TASK_SIZE) | |
94 | return -ENOMEM; | |
95 | ||
96 | if (addr) { | |
97 | if (do_align) | |
98 | addr = COLOUR_ALIGN(addr, pgoff); | |
99 | else | |
100 | addr = PAGE_ALIGN(addr); | |
101 | ||
102 | vma = find_vma(mm, addr); | |
103 | if (TASK_SIZE - len >= addr && | |
104 | (!vma || addr + len <= vma->vm_start)) | |
105 | return addr; | |
106 | } | |
1363c3cd WW |
107 | if (len > mm->cached_hole_size) { |
108 | start_addr = addr = mm->free_area_cache; | |
109 | } else { | |
7dbaa466 | 110 | start_addr = addr = mm->mmap_base; |
1363c3cd WW |
111 | mm->cached_hole_size = 0; |
112 | } | |
1da177e4 LT |
113 | |
114 | full_search: | |
115 | if (do_align) | |
116 | addr = COLOUR_ALIGN(addr, pgoff); | |
117 | else | |
118 | addr = PAGE_ALIGN(addr); | |
119 | ||
120 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { | |
121 | /* At this point: (!vma || addr < vma->vm_end). */ | |
122 | if (TASK_SIZE - len < addr) { | |
123 | /* | |
124 | * Start a new search - just in case we missed | |
125 | * some holes. | |
126 | */ | |
127 | if (start_addr != TASK_UNMAPPED_BASE) { | |
128 | start_addr = addr = TASK_UNMAPPED_BASE; | |
1363c3cd | 129 | mm->cached_hole_size = 0; |
1da177e4 LT |
130 | goto full_search; |
131 | } | |
132 | return -ENOMEM; | |
133 | } | |
134 | if (!vma || addr + len <= vma->vm_start) { | |
135 | /* | |
136 | * Remember the place where we stopped the search: | |
137 | */ | |
138 | mm->free_area_cache = addr + len; | |
139 | return addr; | |
140 | } | |
1363c3cd WW |
141 | if (addr + mm->cached_hole_size < vma->vm_start) |
142 | mm->cached_hole_size = vma->vm_start - addr; | |
1da177e4 LT |
143 | addr = vma->vm_end; |
144 | if (do_align) | |
145 | addr = COLOUR_ALIGN(addr, pgoff); | |
146 | } | |
147 | } | |
148 | ||
7dbaa466 RH |
149 | unsigned long |
150 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
151 | const unsigned long len, const unsigned long pgoff, | |
152 | const unsigned long flags) | |
153 | { | |
154 | struct vm_area_struct *vma; | |
155 | struct mm_struct *mm = current->mm; | |
156 | unsigned long addr = addr0; | |
157 | int do_align = 0; | |
158 | int aliasing = cache_is_vipt_aliasing(); | |
159 | ||
160 | /* | |
161 | * We only need to do colour alignment if either the I or D | |
162 | * caches alias. | |
163 | */ | |
164 | if (aliasing) | |
165 | do_align = filp || (flags & MAP_SHARED); | |
166 | ||
167 | /* requested length too big for entire address space */ | |
168 | if (len > TASK_SIZE) | |
169 | return -ENOMEM; | |
170 | ||
171 | if (flags & MAP_FIXED) { | |
172 | if (aliasing && flags & MAP_SHARED && | |
173 | (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) | |
174 | return -EINVAL; | |
175 | return addr; | |
176 | } | |
177 | ||
178 | /* requesting a specific address */ | |
179 | if (addr) { | |
180 | if (do_align) | |
181 | addr = COLOUR_ALIGN(addr, pgoff); | |
182 | else | |
183 | addr = PAGE_ALIGN(addr); | |
184 | vma = find_vma(mm, addr); | |
185 | if (TASK_SIZE - len >= addr && | |
186 | (!vma || addr + len <= vma->vm_start)) | |
187 | return addr; | |
188 | } | |
189 | ||
190 | /* check if free_area_cache is useful for us */ | |
191 | if (len <= mm->cached_hole_size) { | |
192 | mm->cached_hole_size = 0; | |
193 | mm->free_area_cache = mm->mmap_base; | |
194 | } | |
195 | ||
196 | /* either no address requested or can't fit in requested address hole */ | |
197 | addr = mm->free_area_cache; | |
198 | if (do_align) { | |
199 | unsigned long base = COLOUR_ALIGN_DOWN(addr - len, pgoff); | |
200 | addr = base + len; | |
201 | } | |
202 | ||
203 | /* make sure it can fit in the remaining address space */ | |
204 | if (addr > len) { | |
205 | vma = find_vma(mm, addr-len); | |
206 | if (!vma || addr <= vma->vm_start) | |
207 | /* remember the address as a hint for next time */ | |
208 | return (mm->free_area_cache = addr-len); | |
209 | } | |
210 | ||
211 | if (mm->mmap_base < len) | |
212 | goto bottomup; | |
213 | ||
214 | addr = mm->mmap_base - len; | |
215 | if (do_align) | |
216 | addr = COLOUR_ALIGN_DOWN(addr, pgoff); | |
217 | ||
218 | do { | |
219 | /* | |
220 | * Lookup failure means no vma is above this address, | |
221 | * else if new region fits below vma->vm_start, | |
222 | * return with success: | |
223 | */ | |
224 | vma = find_vma(mm, addr); | |
225 | if (!vma || addr+len <= vma->vm_start) | |
226 | /* remember the address as a hint for next time */ | |
227 | return (mm->free_area_cache = addr); | |
228 | ||
229 | /* remember the largest hole we saw so far */ | |
230 | if (addr + mm->cached_hole_size < vma->vm_start) | |
231 | mm->cached_hole_size = vma->vm_start - addr; | |
232 | ||
233 | /* try just below the current vma->vm_start */ | |
234 | addr = vma->vm_start - len; | |
235 | if (do_align) | |
236 | addr = COLOUR_ALIGN_DOWN(addr, pgoff); | |
237 | } while (len < vma->vm_start); | |
238 | ||
239 | bottomup: | |
240 | /* | |
241 | * A failed mmap() very likely causes application failure, | |
242 | * so fall back to the bottom-up function here. This scenario | |
243 | * can happen with large stack limits and large mmap() | |
244 | * allocations. | |
245 | */ | |
246 | mm->cached_hole_size = ~0UL; | |
247 | mm->free_area_cache = TASK_UNMAPPED_BASE; | |
248 | addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); | |
249 | /* | |
250 | * Restore the topdown base: | |
251 | */ | |
252 | mm->free_area_cache = mm->mmap_base; | |
253 | mm->cached_hole_size = ~0UL; | |
254 | ||
255 | return addr; | |
256 | } | |
257 | ||
258 | void arch_pick_mmap_layout(struct mm_struct *mm) | |
259 | { | |
260 | unsigned long random_factor = 0UL; | |
261 | ||
262 | /* 8 bits of randomness in 20 address space bits */ | |
263 | if ((current->flags & PF_RANDOMIZE) && | |
264 | !(current->personality & ADDR_NO_RANDOMIZE)) | |
265 | random_factor = (get_random_int() % (1 << 8)) << PAGE_SHIFT; | |
266 | ||
267 | if (mmap_is_legacy()) { | |
268 | mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; | |
269 | mm->get_unmapped_area = arch_get_unmapped_area; | |
270 | mm->unmap_area = arch_unmap_area; | |
271 | } else { | |
272 | mm->mmap_base = mmap_base(random_factor); | |
273 | mm->get_unmapped_area = arch_get_unmapped_area_topdown; | |
274 | mm->unmap_area = arch_unmap_area_topdown; | |
275 | } | |
276 | } | |
51635ad2 LB |
277 | |
278 | /* | |
279 | * You really shouldn't be using read() or write() on /dev/mem. This | |
280 | * might go away in the future. | |
281 | */ | |
282 | int valid_phys_addr_range(unsigned long addr, size_t size) | |
283 | { | |
9ae3ae0b AR |
284 | if (addr < PHYS_OFFSET) |
285 | return 0; | |
6806bfe1 | 286 | if (addr + size > __pa(high_memory - 1) + 1) |
51635ad2 LB |
287 | return 0; |
288 | ||
289 | return 1; | |
290 | } | |
291 | ||
292 | /* | |
293 | * We don't use supersection mappings for mmap() on /dev/mem, which | |
294 | * means that we can't map the memory area above the 4G barrier into | |
295 | * userspace. | |
296 | */ | |
297 | int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) | |
298 | { | |
299 | return !(pfn + (size >> PAGE_SHIFT) > 0x00100000); | |
300 | } | |
087aaffc NP |
301 | |
302 | #ifdef CONFIG_STRICT_DEVMEM | |
303 | ||
304 | #include <linux/ioport.h> | |
305 | ||
306 | /* | |
307 | * devmem_is_allowed() checks to see if /dev/mem access to a certain | |
308 | * address is valid. The argument is a physical page number. | |
309 | * We mimic x86 here by disallowing access to system RAM as well as | |
310 | * device-exclusive MMIO regions. This effectively disable read()/write() | |
311 | * on /dev/mem. | |
312 | */ | |
313 | int devmem_is_allowed(unsigned long pfn) | |
314 | { | |
315 | if (iomem_is_exclusive(pfn << PAGE_SHIFT)) | |
316 | return 0; | |
317 | if (!page_is_ram(pfn)) | |
318 | return 1; | |
319 | return 0; | |
320 | } | |
321 | ||
322 | #endif |