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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/drivers/char/mem.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
d7d4d849 | 6 | * Added devfs support. |
1da177e4 | 7 | * Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu> |
af901ca1 | 8 | * Shared /dev/zero mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com> |
1da177e4 LT |
9 | */ |
10 | ||
1da177e4 LT |
11 | #include <linux/mm.h> |
12 | #include <linux/miscdevice.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/vmalloc.h> | |
15 | #include <linux/mman.h> | |
16 | #include <linux/random.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/raw.h> | |
19 | #include <linux/tty.h> | |
20 | #include <linux/capability.h> | |
1da177e4 LT |
21 | #include <linux/ptrace.h> |
22 | #include <linux/device.h> | |
50b1fdbd | 23 | #include <linux/highmem.h> |
1da177e4 | 24 | #include <linux/backing-dev.h> |
d6b29d7c | 25 | #include <linux/splice.h> |
b8a3ad5b | 26 | #include <linux/pfn.h> |
66300e66 | 27 | #include <linux/export.h> |
e1612de9 | 28 | #include <linux/io.h> |
a27bb332 | 29 | #include <linux/aio.h> |
1da177e4 LT |
30 | |
31 | #include <asm/uaccess.h> | |
1da177e4 LT |
32 | |
33 | #ifdef CONFIG_IA64 | |
34 | # include <linux/efi.h> | |
35 | #endif | |
36 | ||
e1612de9 HM |
37 | #define DEVPORT_MINOR 4 |
38 | ||
f222318e WF |
39 | static inline unsigned long size_inside_page(unsigned long start, |
40 | unsigned long size) | |
41 | { | |
42 | unsigned long sz; | |
43 | ||
7fabaddd | 44 | sz = PAGE_SIZE - (start & (PAGE_SIZE - 1)); |
f222318e | 45 | |
7fabaddd | 46 | return min(sz, size); |
f222318e WF |
47 | } |
48 | ||
1da177e4 | 49 | #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE |
7e6735c3 | 50 | static inline int valid_phys_addr_range(phys_addr_t addr, size_t count) |
1da177e4 | 51 | { |
cfaf346c | 52 | return addr + count <= __pa(high_memory); |
1da177e4 | 53 | } |
80851ef2 | 54 | |
06c67bef | 55 | static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) |
80851ef2 BH |
56 | { |
57 | return 1; | |
58 | } | |
1da177e4 LT |
59 | #endif |
60 | ||
d092633b | 61 | #ifdef CONFIG_STRICT_DEVMEM |
e2beb3ea | 62 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 | 63 | { |
e2beb3ea VP |
64 | u64 from = ((u64)pfn) << PAGE_SHIFT; |
65 | u64 to = from + size; | |
66 | u64 cursor = from; | |
67 | ||
68 | while (cursor < to) { | |
69 | if (!devmem_is_allowed(pfn)) { | |
70 | printk(KERN_INFO | |
71 | "Program %s tried to access /dev/mem between %Lx->%Lx.\n", | |
ae531c26 AV |
72 | current->comm, from, to); |
73 | return 0; | |
74 | } | |
e2beb3ea VP |
75 | cursor += PAGE_SIZE; |
76 | pfn++; | |
ae531c26 AV |
77 | } |
78 | return 1; | |
79 | } | |
80 | #else | |
e2beb3ea | 81 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 AV |
82 | { |
83 | return 1; | |
84 | } | |
85 | #endif | |
86 | ||
4707a341 TR |
87 | #ifndef unxlate_dev_mem_ptr |
88 | #define unxlate_dev_mem_ptr unxlate_dev_mem_ptr | |
89 | void __weak unxlate_dev_mem_ptr(phys_addr_t phys, void *addr) | |
e045fb2a | 90 | { |
91 | } | |
4707a341 | 92 | #endif |
e045fb2a | 93 | |
1da177e4 | 94 | /* |
d7d4d849 AM |
95 | * This funcion reads the *physical* memory. The f_pos points directly to the |
96 | * memory location. | |
1da177e4 | 97 | */ |
d7d4d849 | 98 | static ssize_t read_mem(struct file *file, char __user *buf, |
1da177e4 LT |
99 | size_t count, loff_t *ppos) |
100 | { | |
7e6735c3 | 101 | phys_addr_t p = *ppos; |
1da177e4 | 102 | ssize_t read, sz; |
4707a341 | 103 | void *ptr; |
1da177e4 | 104 | |
08d2d00b PT |
105 | if (p != *ppos) |
106 | return 0; | |
107 | ||
136939a2 | 108 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
109 | return -EFAULT; |
110 | read = 0; | |
111 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
112 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
113 | if (p < PAGE_SIZE) { | |
7fabaddd | 114 | sz = size_inside_page(p, count); |
1da177e4 LT |
115 | if (sz > 0) { |
116 | if (clear_user(buf, sz)) | |
117 | return -EFAULT; | |
d7d4d849 AM |
118 | buf += sz; |
119 | p += sz; | |
120 | count -= sz; | |
121 | read += sz; | |
1da177e4 LT |
122 | } |
123 | } | |
124 | #endif | |
125 | ||
126 | while (count > 0) { | |
fa29e97b WF |
127 | unsigned long remaining; |
128 | ||
f222318e | 129 | sz = size_inside_page(p, count); |
1da177e4 | 130 | |
e045fb2a | 131 | if (!range_is_allowed(p >> PAGE_SHIFT, count)) |
132 | return -EPERM; | |
133 | ||
1da177e4 | 134 | /* |
d7d4d849 AM |
135 | * On ia64 if a page has been mapped somewhere as uncached, then |
136 | * it must also be accessed uncached by the kernel or data | |
137 | * corruption may occur. | |
1da177e4 LT |
138 | */ |
139 | ptr = xlate_dev_mem_ptr(p); | |
e045fb2a | 140 | if (!ptr) |
141 | return -EFAULT; | |
1da177e4 | 142 | |
fa29e97b | 143 | remaining = copy_to_user(buf, ptr, sz); |
e045fb2a | 144 | unxlate_dev_mem_ptr(p, ptr); |
fa29e97b WF |
145 | if (remaining) |
146 | return -EFAULT; | |
e045fb2a | 147 | |
1da177e4 LT |
148 | buf += sz; |
149 | p += sz; | |
150 | count -= sz; | |
151 | read += sz; | |
152 | } | |
153 | ||
154 | *ppos += read; | |
155 | return read; | |
156 | } | |
157 | ||
d7d4d849 | 158 | static ssize_t write_mem(struct file *file, const char __user *buf, |
1da177e4 LT |
159 | size_t count, loff_t *ppos) |
160 | { | |
7e6735c3 | 161 | phys_addr_t p = *ppos; |
1da177e4 LT |
162 | ssize_t written, sz; |
163 | unsigned long copied; | |
164 | void *ptr; | |
165 | ||
08d2d00b PT |
166 | if (p != *ppos) |
167 | return -EFBIG; | |
168 | ||
136939a2 | 169 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
170 | return -EFAULT; |
171 | ||
172 | written = 0; | |
173 | ||
174 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
175 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
176 | if (p < PAGE_SIZE) { | |
7fabaddd | 177 | sz = size_inside_page(p, count); |
1da177e4 LT |
178 | /* Hmm. Do something? */ |
179 | buf += sz; | |
180 | p += sz; | |
181 | count -= sz; | |
182 | written += sz; | |
183 | } | |
184 | #endif | |
185 | ||
186 | while (count > 0) { | |
f222318e | 187 | sz = size_inside_page(p, count); |
1da177e4 | 188 | |
e045fb2a | 189 | if (!range_is_allowed(p >> PAGE_SHIFT, sz)) |
190 | return -EPERM; | |
191 | ||
1da177e4 | 192 | /* |
d7d4d849 AM |
193 | * On ia64 if a page has been mapped somewhere as uncached, then |
194 | * it must also be accessed uncached by the kernel or data | |
195 | * corruption may occur. | |
1da177e4 LT |
196 | */ |
197 | ptr = xlate_dev_mem_ptr(p); | |
e045fb2a | 198 | if (!ptr) { |
199 | if (written) | |
200 | break; | |
201 | return -EFAULT; | |
202 | } | |
1da177e4 LT |
203 | |
204 | copied = copy_from_user(ptr, buf, sz); | |
fa29e97b | 205 | unxlate_dev_mem_ptr(p, ptr); |
1da177e4 | 206 | if (copied) { |
c654d60e JB |
207 | written += sz - copied; |
208 | if (written) | |
209 | break; | |
1da177e4 LT |
210 | return -EFAULT; |
211 | } | |
e045fb2a | 212 | |
1da177e4 LT |
213 | buf += sz; |
214 | p += sz; | |
215 | count -= sz; | |
216 | written += sz; | |
217 | } | |
218 | ||
219 | *ppos += written; | |
220 | return written; | |
221 | } | |
222 | ||
d7d4d849 | 223 | int __weak phys_mem_access_prot_allowed(struct file *file, |
f0970c13 | 224 | unsigned long pfn, unsigned long size, pgprot_t *vma_prot) |
225 | { | |
226 | return 1; | |
227 | } | |
228 | ||
44ac8413 | 229 | #ifndef __HAVE_PHYS_MEM_ACCESS_PROT |
d7d4d849 AM |
230 | |
231 | /* | |
232 | * Architectures vary in how they handle caching for addresses | |
233 | * outside of main memory. | |
234 | * | |
235 | */ | |
ea56f411 | 236 | #ifdef pgprot_noncached |
7e6735c3 | 237 | static int uncached_access(struct file *file, phys_addr_t addr) |
d7d4d849 AM |
238 | { |
239 | #if defined(CONFIG_IA64) | |
240 | /* | |
241 | * On ia64, we ignore O_DSYNC because we cannot tolerate memory | |
242 | * attribute aliases. | |
243 | */ | |
244 | return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); | |
245 | #elif defined(CONFIG_MIPS) | |
246 | { | |
247 | extern int __uncached_access(struct file *file, | |
248 | unsigned long addr); | |
249 | ||
250 | return __uncached_access(file, addr); | |
251 | } | |
252 | #else | |
253 | /* | |
254 | * Accessing memory above the top the kernel knows about or through a | |
255 | * file pointer | |
256 | * that was marked O_DSYNC will be done non-cached. | |
257 | */ | |
258 | if (file->f_flags & O_DSYNC) | |
259 | return 1; | |
260 | return addr >= __pa(high_memory); | |
261 | #endif | |
262 | } | |
ea56f411 | 263 | #endif |
d7d4d849 | 264 | |
44ac8413 BH |
265 | static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, |
266 | unsigned long size, pgprot_t vma_prot) | |
267 | { | |
268 | #ifdef pgprot_noncached | |
7e6735c3 | 269 | phys_addr_t offset = pfn << PAGE_SHIFT; |
44ac8413 BH |
270 | |
271 | if (uncached_access(file, offset)) | |
272 | return pgprot_noncached(vma_prot); | |
273 | #endif | |
274 | return vma_prot; | |
275 | } | |
276 | #endif | |
277 | ||
5da6185b DH |
278 | #ifndef CONFIG_MMU |
279 | static unsigned long get_unmapped_area_mem(struct file *file, | |
280 | unsigned long addr, | |
281 | unsigned long len, | |
282 | unsigned long pgoff, | |
283 | unsigned long flags) | |
284 | { | |
285 | if (!valid_mmap_phys_addr_range(pgoff, len)) | |
286 | return (unsigned long) -EINVAL; | |
8a93258c | 287 | return pgoff << PAGE_SHIFT; |
5da6185b DH |
288 | } |
289 | ||
290 | /* can't do an in-place private mapping if there's no MMU */ | |
291 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
292 | { | |
293 | return vma->vm_flags & VM_MAYSHARE; | |
294 | } | |
295 | #else | |
296 | #define get_unmapped_area_mem NULL | |
297 | ||
298 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
299 | { | |
300 | return 1; | |
301 | } | |
302 | #endif | |
303 | ||
f0f37e2f | 304 | static const struct vm_operations_struct mmap_mem_ops = { |
7ae8ed50 RR |
305 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
306 | .access = generic_access_phys | |
307 | #endif | |
e7f260a2 | 308 | }; |
309 | ||
d7d4d849 | 310 | static int mmap_mem(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 311 | { |
80851ef2 BH |
312 | size_t size = vma->vm_end - vma->vm_start; |
313 | ||
06c67bef | 314 | if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) |
80851ef2 BH |
315 | return -EINVAL; |
316 | ||
5da6185b DH |
317 | if (!private_mapping_ok(vma)) |
318 | return -ENOSYS; | |
319 | ||
e2beb3ea VP |
320 | if (!range_is_allowed(vma->vm_pgoff, size)) |
321 | return -EPERM; | |
322 | ||
f0970c13 | 323 | if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, |
324 | &vma->vm_page_prot)) | |
325 | return -EINVAL; | |
326 | ||
8b150478 | 327 | vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, |
80851ef2 | 328 | size, |
1da177e4 | 329 | vma->vm_page_prot); |
1da177e4 | 330 | |
e7f260a2 | 331 | vma->vm_ops = &mmap_mem_ops; |
332 | ||
314e51b9 | 333 | /* Remap-pfn-range will mark the range VM_IO */ |
1da177e4 LT |
334 | if (remap_pfn_range(vma, |
335 | vma->vm_start, | |
336 | vma->vm_pgoff, | |
80851ef2 | 337 | size, |
e7f260a2 | 338 | vma->vm_page_prot)) { |
1da177e4 | 339 | return -EAGAIN; |
e7f260a2 | 340 | } |
1da177e4 LT |
341 | return 0; |
342 | } | |
343 | ||
d7d4d849 | 344 | static int mmap_kmem(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 345 | { |
4bb82551 LT |
346 | unsigned long pfn; |
347 | ||
6d3154cc LT |
348 | /* Turn a kernel-virtual address into a physical page frame */ |
349 | pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; | |
4bb82551 | 350 | |
1da177e4 | 351 | /* |
d7d4d849 AM |
352 | * RED-PEN: on some architectures there is more mapped memory than |
353 | * available in mem_map which pfn_valid checks for. Perhaps should add a | |
354 | * new macro here. | |
1da177e4 LT |
355 | * |
356 | * RED-PEN: vmalloc is not supported right now. | |
357 | */ | |
4bb82551 | 358 | if (!pfn_valid(pfn)) |
1da177e4 | 359 | return -EIO; |
4bb82551 LT |
360 | |
361 | vma->vm_pgoff = pfn; | |
1da177e4 LT |
362 | return mmap_mem(file, vma); |
363 | } | |
364 | ||
1da177e4 LT |
365 | /* |
366 | * This function reads the *virtual* memory as seen by the kernel. | |
367 | */ | |
d7d4d849 | 368 | static ssize_t read_kmem(struct file *file, char __user *buf, |
1da177e4 LT |
369 | size_t count, loff_t *ppos) |
370 | { | |
371 | unsigned long p = *ppos; | |
372 | ssize_t low_count, read, sz; | |
890537b3 | 373 | char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ |
325fda71 | 374 | int err = 0; |
1da177e4 LT |
375 | |
376 | read = 0; | |
377 | if (p < (unsigned long) high_memory) { | |
378 | low_count = count; | |
d7d4d849 AM |
379 | if (count > (unsigned long)high_memory - p) |
380 | low_count = (unsigned long)high_memory - p; | |
1da177e4 LT |
381 | |
382 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
383 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
384 | if (p < PAGE_SIZE && low_count > 0) { | |
7fabaddd WF |
385 | sz = size_inside_page(p, low_count); |
386 | if (clear_user(buf, sz)) | |
1da177e4 | 387 | return -EFAULT; |
7fabaddd WF |
388 | buf += sz; |
389 | p += sz; | |
390 | read += sz; | |
391 | low_count -= sz; | |
392 | count -= sz; | |
1da177e4 LT |
393 | } |
394 | #endif | |
395 | while (low_count > 0) { | |
f222318e | 396 | sz = size_inside_page(p, low_count); |
1da177e4 LT |
397 | |
398 | /* | |
399 | * On ia64 if a page has been mapped somewhere as | |
400 | * uncached, then it must also be accessed uncached | |
401 | * by the kernel or data corruption may occur | |
402 | */ | |
4707a341 | 403 | kbuf = xlate_dev_kmem_ptr((void *)p); |
1da177e4 LT |
404 | |
405 | if (copy_to_user(buf, kbuf, sz)) | |
406 | return -EFAULT; | |
407 | buf += sz; | |
408 | p += sz; | |
409 | read += sz; | |
410 | low_count -= sz; | |
411 | count -= sz; | |
412 | } | |
413 | } | |
414 | ||
415 | if (count > 0) { | |
416 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
417 | if (!kbuf) | |
418 | return -ENOMEM; | |
419 | while (count > 0) { | |
80ad89a0 | 420 | sz = size_inside_page(p, count); |
325fda71 KH |
421 | if (!is_vmalloc_or_module_addr((void *)p)) { |
422 | err = -ENXIO; | |
423 | break; | |
424 | } | |
80ad89a0 WF |
425 | sz = vread(kbuf, (char *)p, sz); |
426 | if (!sz) | |
1da177e4 | 427 | break; |
80ad89a0 | 428 | if (copy_to_user(buf, kbuf, sz)) { |
325fda71 KH |
429 | err = -EFAULT; |
430 | break; | |
1da177e4 | 431 | } |
80ad89a0 WF |
432 | count -= sz; |
433 | buf += sz; | |
434 | read += sz; | |
435 | p += sz; | |
1da177e4 LT |
436 | } |
437 | free_page((unsigned long)kbuf); | |
438 | } | |
325fda71 KH |
439 | *ppos = p; |
440 | return read ? read : err; | |
1da177e4 LT |
441 | } |
442 | ||
443 | ||
d7d4d849 AM |
444 | static ssize_t do_write_kmem(unsigned long p, const char __user *buf, |
445 | size_t count, loff_t *ppos) | |
1da177e4 LT |
446 | { |
447 | ssize_t written, sz; | |
448 | unsigned long copied; | |
449 | ||
450 | written = 0; | |
451 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
452 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
ee32398f WF |
453 | if (p < PAGE_SIZE) { |
454 | sz = size_inside_page(p, count); | |
1da177e4 LT |
455 | /* Hmm. Do something? */ |
456 | buf += sz; | |
457 | p += sz; | |
1da177e4 LT |
458 | count -= sz; |
459 | written += sz; | |
460 | } | |
461 | #endif | |
462 | ||
463 | while (count > 0) { | |
4707a341 | 464 | void *ptr; |
1da177e4 | 465 | |
ee32398f | 466 | sz = size_inside_page(p, count); |
1da177e4 LT |
467 | |
468 | /* | |
d7d4d849 AM |
469 | * On ia64 if a page has been mapped somewhere as uncached, then |
470 | * it must also be accessed uncached by the kernel or data | |
471 | * corruption may occur. | |
1da177e4 | 472 | */ |
4707a341 | 473 | ptr = xlate_dev_kmem_ptr((void *)p); |
1da177e4 LT |
474 | |
475 | copied = copy_from_user(ptr, buf, sz); | |
476 | if (copied) { | |
c654d60e JB |
477 | written += sz - copied; |
478 | if (written) | |
479 | break; | |
1da177e4 LT |
480 | return -EFAULT; |
481 | } | |
482 | buf += sz; | |
483 | p += sz; | |
1da177e4 LT |
484 | count -= sz; |
485 | written += sz; | |
486 | } | |
487 | ||
488 | *ppos += written; | |
489 | return written; | |
490 | } | |
491 | ||
1da177e4 LT |
492 | /* |
493 | * This function writes to the *virtual* memory as seen by the kernel. | |
494 | */ | |
d7d4d849 | 495 | static ssize_t write_kmem(struct file *file, const char __user *buf, |
1da177e4 LT |
496 | size_t count, loff_t *ppos) |
497 | { | |
498 | unsigned long p = *ppos; | |
499 | ssize_t wrote = 0; | |
500 | ssize_t virtr = 0; | |
890537b3 | 501 | char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ |
325fda71 | 502 | int err = 0; |
1da177e4 LT |
503 | |
504 | if (p < (unsigned long) high_memory) { | |
80ad89a0 WF |
505 | unsigned long to_write = min_t(unsigned long, count, |
506 | (unsigned long)high_memory - p); | |
ee32398f | 507 | wrote = do_write_kmem(p, buf, to_write, ppos); |
80ad89a0 WF |
508 | if (wrote != to_write) |
509 | return wrote; | |
1da177e4 LT |
510 | p += wrote; |
511 | buf += wrote; | |
512 | count -= wrote; | |
513 | } | |
514 | ||
515 | if (count > 0) { | |
516 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
517 | if (!kbuf) | |
518 | return wrote ? wrote : -ENOMEM; | |
519 | while (count > 0) { | |
80ad89a0 WF |
520 | unsigned long sz = size_inside_page(p, count); |
521 | unsigned long n; | |
1da177e4 | 522 | |
325fda71 KH |
523 | if (!is_vmalloc_or_module_addr((void *)p)) { |
524 | err = -ENXIO; | |
525 | break; | |
526 | } | |
80ad89a0 WF |
527 | n = copy_from_user(kbuf, buf, sz); |
528 | if (n) { | |
325fda71 KH |
529 | err = -EFAULT; |
530 | break; | |
1da177e4 | 531 | } |
c85e9a97 | 532 | vwrite(kbuf, (char *)p, sz); |
80ad89a0 WF |
533 | count -= sz; |
534 | buf += sz; | |
535 | virtr += sz; | |
536 | p += sz; | |
1da177e4 LT |
537 | } |
538 | free_page((unsigned long)kbuf); | |
539 | } | |
540 | ||
325fda71 KH |
541 | *ppos = p; |
542 | return virtr + wrote ? : err; | |
1da177e4 LT |
543 | } |
544 | ||
d7d4d849 | 545 | static ssize_t read_port(struct file *file, char __user *buf, |
1da177e4 LT |
546 | size_t count, loff_t *ppos) |
547 | { | |
548 | unsigned long i = *ppos; | |
549 | char __user *tmp = buf; | |
550 | ||
551 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
d7d4d849 | 552 | return -EFAULT; |
1da177e4 | 553 | while (count-- > 0 && i < 65536) { |
d7d4d849 AM |
554 | if (__put_user(inb(i), tmp) < 0) |
555 | return -EFAULT; | |
1da177e4 LT |
556 | i++; |
557 | tmp++; | |
558 | } | |
559 | *ppos = i; | |
560 | return tmp-buf; | |
561 | } | |
562 | ||
d7d4d849 | 563 | static ssize_t write_port(struct file *file, const char __user *buf, |
1da177e4 LT |
564 | size_t count, loff_t *ppos) |
565 | { | |
566 | unsigned long i = *ppos; | |
890537b3 | 567 | const char __user *tmp = buf; |
1da177e4 | 568 | |
d7d4d849 | 569 | if (!access_ok(VERIFY_READ, buf, count)) |
1da177e4 LT |
570 | return -EFAULT; |
571 | while (count-- > 0 && i < 65536) { | |
572 | char c; | |
c654d60e JB |
573 | if (__get_user(c, tmp)) { |
574 | if (tmp > buf) | |
575 | break; | |
d7d4d849 | 576 | return -EFAULT; |
c654d60e | 577 | } |
d7d4d849 | 578 | outb(c, i); |
1da177e4 LT |
579 | i++; |
580 | tmp++; | |
581 | } | |
582 | *ppos = i; | |
583 | return tmp-buf; | |
584 | } | |
1da177e4 | 585 | |
d7d4d849 | 586 | static ssize_t read_null(struct file *file, char __user *buf, |
1da177e4 LT |
587 | size_t count, loff_t *ppos) |
588 | { | |
589 | return 0; | |
590 | } | |
591 | ||
d7d4d849 | 592 | static ssize_t write_null(struct file *file, const char __user *buf, |
1da177e4 LT |
593 | size_t count, loff_t *ppos) |
594 | { | |
595 | return count; | |
596 | } | |
597 | ||
162934de ZB |
598 | static ssize_t aio_read_null(struct kiocb *iocb, const struct iovec *iov, |
599 | unsigned long nr_segs, loff_t pos) | |
600 | { | |
601 | return 0; | |
602 | } | |
603 | ||
604 | static ssize_t aio_write_null(struct kiocb *iocb, const struct iovec *iov, | |
605 | unsigned long nr_segs, loff_t pos) | |
606 | { | |
607 | return iov_length(iov, nr_segs); | |
608 | } | |
609 | ||
1ebd32fc JA |
610 | static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, |
611 | struct splice_desc *sd) | |
612 | { | |
613 | return sd->len; | |
614 | } | |
615 | ||
d7d4d849 | 616 | static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out, |
1ebd32fc JA |
617 | loff_t *ppos, size_t len, unsigned int flags) |
618 | { | |
619 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); | |
620 | } | |
621 | ||
13ba33e8 | 622 | static ssize_t read_iter_zero(struct kiocb *iocb, struct iov_iter *iter) |
1da177e4 | 623 | { |
13ba33e8 | 624 | size_t written = 0; |
1da177e4 | 625 | |
13ba33e8 AV |
626 | while (iov_iter_count(iter)) { |
627 | size_t chunk = iov_iter_count(iter), n; | |
557ed1fa NP |
628 | if (chunk > PAGE_SIZE) |
629 | chunk = PAGE_SIZE; /* Just for latency reasons */ | |
13ba33e8 AV |
630 | n = iov_iter_zero(chunk, iter); |
631 | if (!n && iov_iter_count(iter)) | |
632 | return written ? written : -EFAULT; | |
633 | written += n; | |
2b838687 LT |
634 | if (signal_pending(current)) |
635 | return written ? written : -ERESTARTSYS; | |
1da177e4 LT |
636 | cond_resched(); |
637 | } | |
13ba33e8 | 638 | return written; |
162934de ZB |
639 | } |
640 | ||
d7d4d849 | 641 | static int mmap_zero(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 642 | { |
557ed1fa | 643 | #ifndef CONFIG_MMU |
1da177e4 | 644 | return -ENOSYS; |
557ed1fa NP |
645 | #endif |
646 | if (vma->vm_flags & VM_SHARED) | |
647 | return shmem_zero_setup(vma); | |
648 | return 0; | |
1da177e4 | 649 | } |
1da177e4 | 650 | |
d7d4d849 | 651 | static ssize_t write_full(struct file *file, const char __user *buf, |
1da177e4 LT |
652 | size_t count, loff_t *ppos) |
653 | { | |
654 | return -ENOSPC; | |
655 | } | |
656 | ||
657 | /* | |
658 | * Special lseek() function for /dev/null and /dev/zero. Most notably, you | |
659 | * can fopen() both devices with "a" now. This was previously impossible. | |
660 | * -- SRB. | |
661 | */ | |
d7d4d849 | 662 | static loff_t null_lseek(struct file *file, loff_t offset, int orig) |
1da177e4 LT |
663 | { |
664 | return file->f_pos = 0; | |
665 | } | |
666 | ||
667 | /* | |
668 | * The memory devices use the full 32/64 bits of the offset, and so we cannot | |
669 | * check against negative addresses: they are ok. The return value is weird, | |
670 | * though, in that case (0). | |
671 | * | |
672 | * also note that seeking relative to the "end of file" isn't supported: | |
673 | * it has no meaning, so it returns -EINVAL. | |
674 | */ | |
d7d4d849 | 675 | static loff_t memory_lseek(struct file *file, loff_t offset, int orig) |
1da177e4 LT |
676 | { |
677 | loff_t ret; | |
678 | ||
496ad9aa | 679 | mutex_lock(&file_inode(file)->i_mutex); |
1da177e4 | 680 | switch (orig) { |
d7d4d849 AM |
681 | case SEEK_CUR: |
682 | offset += file->f_pos; | |
d7d4d849 AM |
683 | case SEEK_SET: |
684 | /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */ | |
71811f32 | 685 | if (IS_ERR_VALUE((unsigned long long)offset)) { |
d7d4d849 | 686 | ret = -EOVERFLOW; |
1da177e4 | 687 | break; |
d7d4d849 AM |
688 | } |
689 | file->f_pos = offset; | |
690 | ret = file->f_pos; | |
691 | force_successful_syscall_return(); | |
692 | break; | |
693 | default: | |
694 | ret = -EINVAL; | |
1da177e4 | 695 | } |
496ad9aa | 696 | mutex_unlock(&file_inode(file)->i_mutex); |
1da177e4 LT |
697 | return ret; |
698 | } | |
699 | ||
890537b3 | 700 | static int open_port(struct inode *inode, struct file *filp) |
1da177e4 LT |
701 | { |
702 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; | |
703 | } | |
704 | ||
705 | #define zero_lseek null_lseek | |
706 | #define full_lseek null_lseek | |
707 | #define write_zero write_null | |
162934de | 708 | #define aio_write_zero aio_write_null |
1da177e4 LT |
709 | #define open_mem open_port |
710 | #define open_kmem open_mem | |
711 | ||
73f0718e | 712 | static const struct file_operations __maybe_unused mem_fops = { |
1da177e4 LT |
713 | .llseek = memory_lseek, |
714 | .read = read_mem, | |
715 | .write = write_mem, | |
716 | .mmap = mmap_mem, | |
717 | .open = open_mem, | |
5da6185b | 718 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 LT |
719 | }; |
720 | ||
a8c91252 | 721 | static const struct file_operations __maybe_unused kmem_fops = { |
1da177e4 LT |
722 | .llseek = memory_lseek, |
723 | .read = read_kmem, | |
724 | .write = write_kmem, | |
725 | .mmap = mmap_kmem, | |
726 | .open = open_kmem, | |
5da6185b | 727 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 LT |
728 | }; |
729 | ||
62322d25 | 730 | static const struct file_operations null_fops = { |
1da177e4 LT |
731 | .llseek = null_lseek, |
732 | .read = read_null, | |
733 | .write = write_null, | |
162934de ZB |
734 | .aio_read = aio_read_null, |
735 | .aio_write = aio_write_null, | |
1ebd32fc | 736 | .splice_write = splice_write_null, |
1da177e4 LT |
737 | }; |
738 | ||
3a4bc2fb | 739 | static const struct file_operations __maybe_unused port_fops = { |
1da177e4 LT |
740 | .llseek = memory_lseek, |
741 | .read = read_port, | |
742 | .write = write_port, | |
743 | .open = open_port, | |
744 | }; | |
1da177e4 | 745 | |
62322d25 | 746 | static const struct file_operations zero_fops = { |
1da177e4 | 747 | .llseek = zero_lseek, |
13ba33e8 | 748 | .read = new_sync_read, |
1da177e4 | 749 | .write = write_zero, |
13ba33e8 | 750 | .read_iter = read_iter_zero, |
162934de | 751 | .aio_write = aio_write_zero, |
1da177e4 LT |
752 | .mmap = mmap_zero, |
753 | }; | |
754 | ||
5da6185b DH |
755 | /* |
756 | * capabilities for /dev/zero | |
757 | * - permits private mappings, "copies" are taken of the source of zeros | |
371d217e | 758 | * - no writeback happens |
5da6185b | 759 | */ |
1da177e4 | 760 | static struct backing_dev_info zero_bdi = { |
d993831f | 761 | .name = "char/mem", |
371d217e | 762 | .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK, |
1da177e4 LT |
763 | }; |
764 | ||
62322d25 | 765 | static const struct file_operations full_fops = { |
1da177e4 | 766 | .llseek = full_lseek, |
13ba33e8 AV |
767 | .read = new_sync_read, |
768 | .read_iter = read_iter_zero, | |
1da177e4 LT |
769 | .write = write_full, |
770 | }; | |
771 | ||
389e0cb9 KS |
772 | static const struct memdev { |
773 | const char *name; | |
2c9ede55 | 774 | umode_t mode; |
389e0cb9 KS |
775 | const struct file_operations *fops; |
776 | struct backing_dev_info *dev_info; | |
777 | } devlist[] = { | |
73f0718e | 778 | #ifdef CONFIG_DEVMEM |
e454cea2 | 779 | [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi }, |
73f0718e | 780 | #endif |
b781ecb6 | 781 | #ifdef CONFIG_DEVKMEM |
e454cea2 | 782 | [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi }, |
b781ecb6 | 783 | #endif |
e454cea2 | 784 | [3] = { "null", 0666, &null_fops, NULL }, |
4f911d64 | 785 | #ifdef CONFIG_DEVPORT |
e454cea2 | 786 | [4] = { "port", 0, &port_fops, NULL }, |
1da177e4 | 787 | #endif |
e454cea2 KS |
788 | [5] = { "zero", 0666, &zero_fops, &zero_bdi }, |
789 | [7] = { "full", 0666, &full_fops, NULL }, | |
790 | [8] = { "random", 0666, &random_fops, NULL }, | |
791 | [9] = { "urandom", 0666, &urandom_fops, NULL }, | |
7f3a781d | 792 | #ifdef CONFIG_PRINTK |
e11fea92 | 793 | [11] = { "kmsg", 0644, &kmsg_fops, NULL }, |
7f3a781d | 794 | #endif |
d6f47bef ASF |
795 | }; |
796 | ||
797 | static int memory_open(struct inode *inode, struct file *filp) | |
798 | { | |
389e0cb9 KS |
799 | int minor; |
800 | const struct memdev *dev; | |
d6f47bef | 801 | |
389e0cb9 KS |
802 | minor = iminor(inode); |
803 | if (minor >= ARRAY_SIZE(devlist)) | |
205153aa | 804 | return -ENXIO; |
d6f47bef | 805 | |
389e0cb9 KS |
806 | dev = &devlist[minor]; |
807 | if (!dev->fops) | |
205153aa | 808 | return -ENXIO; |
d6f47bef | 809 | |
389e0cb9 KS |
810 | filp->f_op = dev->fops; |
811 | if (dev->dev_info) | |
812 | filp->f_mapping->backing_dev_info = dev->dev_info; | |
d6f47bef | 813 | |
4a3956c7 KH |
814 | /* Is /dev/mem or /dev/kmem ? */ |
815 | if (dev->dev_info == &directly_mappable_cdev_bdi) | |
816 | filp->f_mode |= FMODE_UNSIGNED_OFFSET; | |
817 | ||
389e0cb9 | 818 | if (dev->fops->open) |
205153aa FW |
819 | return dev->fops->open(inode, filp); |
820 | ||
821 | return 0; | |
1da177e4 LT |
822 | } |
823 | ||
62322d25 | 824 | static const struct file_operations memory_fops = { |
d7d4d849 | 825 | .open = memory_open, |
6038f373 | 826 | .llseek = noop_llseek, |
1da177e4 LT |
827 | }; |
828 | ||
2c9ede55 | 829 | static char *mem_devnode(struct device *dev, umode_t *mode) |
e454cea2 KS |
830 | { |
831 | if (mode && devlist[MINOR(dev->devt)].mode) | |
832 | *mode = devlist[MINOR(dev->devt)].mode; | |
833 | return NULL; | |
834 | } | |
835 | ||
ca8eca68 | 836 | static struct class *mem_class; |
1da177e4 LT |
837 | |
838 | static int __init chr_dev_init(void) | |
839 | { | |
389e0cb9 | 840 | int minor; |
e0bf68dd PZ |
841 | int err; |
842 | ||
843 | err = bdi_init(&zero_bdi); | |
844 | if (err) | |
845 | return err; | |
1da177e4 | 846 | |
d7d4d849 | 847 | if (register_chrdev(MEM_MAJOR, "mem", &memory_fops)) |
1da177e4 LT |
848 | printk("unable to get major %d for memory devs\n", MEM_MAJOR); |
849 | ||
ca8eca68 | 850 | mem_class = class_create(THIS_MODULE, "mem"); |
6e191f7b AB |
851 | if (IS_ERR(mem_class)) |
852 | return PTR_ERR(mem_class); | |
853 | ||
e454cea2 | 854 | mem_class->devnode = mem_devnode; |
389e0cb9 KS |
855 | for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) { |
856 | if (!devlist[minor].name) | |
857 | continue; | |
e1612de9 HM |
858 | |
859 | /* | |
890537b3 | 860 | * Create /dev/port? |
e1612de9 HM |
861 | */ |
862 | if ((minor == DEVPORT_MINOR) && !arch_has_dev_port()) | |
863 | continue; | |
864 | ||
389e0cb9 KS |
865 | device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor), |
866 | NULL, devlist[minor].name); | |
867 | } | |
ebf644c4 | 868 | |
31d1d48e | 869 | return tty_init(); |
1da177e4 LT |
870 | } |
871 | ||
872 | fs_initcall(chr_dev_init); |