Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/drivers/char/mem.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * Added devfs support. | |
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 VG |
23 | #include <linux/highmem.h> |
24 | #include <linux/crash_dump.h> | |
1da177e4 | 25 | #include <linux/backing-dev.h> |
315c215c | 26 | #include <linux/bootmem.h> |
d6b29d7c | 27 | #include <linux/splice.h> |
b8a3ad5b | 28 | #include <linux/pfn.h> |
1da177e4 LT |
29 | |
30 | #include <asm/uaccess.h> | |
31 | #include <asm/io.h> | |
32 | ||
33 | #ifdef CONFIG_IA64 | |
34 | # include <linux/efi.h> | |
35 | #endif | |
36 | ||
f222318e WF |
37 | static inline unsigned long size_inside_page(unsigned long start, |
38 | unsigned long size) | |
39 | { | |
40 | unsigned long sz; | |
41 | ||
42 | if (-start & (PAGE_SIZE - 1)) | |
43 | sz = -start & (PAGE_SIZE - 1); | |
44 | else | |
45 | sz = PAGE_SIZE; | |
46 | ||
47 | return min_t(unsigned long, sz, size); | |
48 | } | |
49 | ||
1da177e4 LT |
50 | /* |
51 | * Architectures vary in how they handle caching for addresses | |
52 | * outside of main memory. | |
53 | * | |
54 | */ | |
55 | static inline int uncached_access(struct file *file, unsigned long addr) | |
56 | { | |
f0970c13 | 57 | #if defined(CONFIG_IA64) |
1da177e4 | 58 | /* |
6b2f3d1f | 59 | * On ia64, we ignore O_DSYNC because we cannot tolerate memory attribute aliases. |
1da177e4 LT |
60 | */ |
61 | return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); | |
24e9d0b9 RB |
62 | #elif defined(CONFIG_MIPS) |
63 | { | |
64 | extern int __uncached_access(struct file *file, | |
65 | unsigned long addr); | |
66 | ||
67 | return __uncached_access(file, addr); | |
68 | } | |
1da177e4 LT |
69 | #else |
70 | /* | |
71 | * Accessing memory above the top the kernel knows about or through a file pointer | |
6b2f3d1f | 72 | * that was marked O_DSYNC will be done non-cached. |
1da177e4 | 73 | */ |
6b2f3d1f | 74 | if (file->f_flags & O_DSYNC) |
1da177e4 LT |
75 | return 1; |
76 | return addr >= __pa(high_memory); | |
77 | #endif | |
78 | } | |
79 | ||
80 | #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE | |
136939a2 | 81 | static inline int valid_phys_addr_range(unsigned long addr, size_t count) |
1da177e4 | 82 | { |
136939a2 | 83 | if (addr + count > __pa(high_memory)) |
1da177e4 LT |
84 | return 0; |
85 | ||
1da177e4 LT |
86 | return 1; |
87 | } | |
80851ef2 | 88 | |
06c67bef | 89 | static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) |
80851ef2 BH |
90 | { |
91 | return 1; | |
92 | } | |
1da177e4 LT |
93 | #endif |
94 | ||
d092633b | 95 | #ifdef CONFIG_STRICT_DEVMEM |
e2beb3ea | 96 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 | 97 | { |
e2beb3ea VP |
98 | u64 from = ((u64)pfn) << PAGE_SHIFT; |
99 | u64 to = from + size; | |
100 | u64 cursor = from; | |
101 | ||
102 | while (cursor < to) { | |
103 | if (!devmem_is_allowed(pfn)) { | |
104 | printk(KERN_INFO | |
105 | "Program %s tried to access /dev/mem between %Lx->%Lx.\n", | |
ae531c26 AV |
106 | current->comm, from, to); |
107 | return 0; | |
108 | } | |
e2beb3ea VP |
109 | cursor += PAGE_SIZE; |
110 | pfn++; | |
ae531c26 AV |
111 | } |
112 | return 1; | |
113 | } | |
114 | #else | |
e2beb3ea | 115 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 AV |
116 | { |
117 | return 1; | |
118 | } | |
119 | #endif | |
120 | ||
e045fb2a | 121 | void __attribute__((weak)) unxlate_dev_mem_ptr(unsigned long phys, void *addr) |
122 | { | |
123 | } | |
124 | ||
1da177e4 LT |
125 | /* |
126 | * This funcion reads the *physical* memory. The f_pos points directly to the | |
127 | * memory location. | |
128 | */ | |
129 | static ssize_t read_mem(struct file * file, char __user * buf, | |
130 | size_t count, loff_t *ppos) | |
131 | { | |
132 | unsigned long p = *ppos; | |
133 | ssize_t read, sz; | |
134 | char *ptr; | |
135 | ||
136939a2 | 136 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
137 | return -EFAULT; |
138 | read = 0; | |
139 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
140 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
141 | if (p < PAGE_SIZE) { | |
142 | sz = PAGE_SIZE - p; | |
143 | if (sz > count) | |
144 | sz = count; | |
145 | if (sz > 0) { | |
146 | if (clear_user(buf, sz)) | |
147 | return -EFAULT; | |
148 | buf += sz; | |
149 | p += sz; | |
150 | count -= sz; | |
151 | read += sz; | |
152 | } | |
153 | } | |
154 | #endif | |
155 | ||
156 | while (count > 0) { | |
fa29e97b WF |
157 | unsigned long remaining; |
158 | ||
f222318e | 159 | sz = size_inside_page(p, count); |
1da177e4 | 160 | |
e045fb2a | 161 | if (!range_is_allowed(p >> PAGE_SHIFT, count)) |
162 | return -EPERM; | |
163 | ||
1da177e4 LT |
164 | /* |
165 | * On ia64 if a page has been mapped somewhere as | |
166 | * uncached, then it must also be accessed uncached | |
167 | * by the kernel or data corruption may occur | |
168 | */ | |
169 | ptr = xlate_dev_mem_ptr(p); | |
e045fb2a | 170 | if (!ptr) |
171 | return -EFAULT; | |
1da177e4 | 172 | |
fa29e97b | 173 | remaining = copy_to_user(buf, ptr, sz); |
e045fb2a | 174 | unxlate_dev_mem_ptr(p, ptr); |
fa29e97b WF |
175 | if (remaining) |
176 | return -EFAULT; | |
e045fb2a | 177 | |
1da177e4 LT |
178 | buf += sz; |
179 | p += sz; | |
180 | count -= sz; | |
181 | read += sz; | |
182 | } | |
183 | ||
184 | *ppos += read; | |
185 | return read; | |
186 | } | |
187 | ||
188 | static ssize_t write_mem(struct file * file, const char __user * buf, | |
189 | size_t count, loff_t *ppos) | |
190 | { | |
191 | unsigned long p = *ppos; | |
192 | ssize_t written, sz; | |
193 | unsigned long copied; | |
194 | void *ptr; | |
195 | ||
136939a2 | 196 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
197 | return -EFAULT; |
198 | ||
199 | written = 0; | |
200 | ||
201 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
202 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
203 | if (p < PAGE_SIZE) { | |
204 | unsigned long sz = PAGE_SIZE - p; | |
205 | if (sz > count) | |
206 | sz = count; | |
207 | /* Hmm. Do something? */ | |
208 | buf += sz; | |
209 | p += sz; | |
210 | count -= sz; | |
211 | written += sz; | |
212 | } | |
213 | #endif | |
214 | ||
215 | while (count > 0) { | |
f222318e | 216 | sz = size_inside_page(p, count); |
1da177e4 | 217 | |
e045fb2a | 218 | if (!range_is_allowed(p >> PAGE_SHIFT, sz)) |
219 | return -EPERM; | |
220 | ||
1da177e4 LT |
221 | /* |
222 | * On ia64 if a page has been mapped somewhere as | |
223 | * uncached, then it must also be accessed uncached | |
224 | * by the kernel or data corruption may occur | |
225 | */ | |
226 | ptr = xlate_dev_mem_ptr(p); | |
e045fb2a | 227 | if (!ptr) { |
228 | if (written) | |
229 | break; | |
230 | return -EFAULT; | |
231 | } | |
1da177e4 LT |
232 | |
233 | copied = copy_from_user(ptr, buf, sz); | |
fa29e97b | 234 | unxlate_dev_mem_ptr(p, ptr); |
1da177e4 | 235 | if (copied) { |
c654d60e JB |
236 | written += sz - copied; |
237 | if (written) | |
238 | break; | |
1da177e4 LT |
239 | return -EFAULT; |
240 | } | |
e045fb2a | 241 | |
1da177e4 LT |
242 | buf += sz; |
243 | p += sz; | |
244 | count -= sz; | |
245 | written += sz; | |
246 | } | |
247 | ||
248 | *ppos += written; | |
249 | return written; | |
250 | } | |
251 | ||
f0970c13 | 252 | int __attribute__((weak)) phys_mem_access_prot_allowed(struct file *file, |
253 | unsigned long pfn, unsigned long size, pgprot_t *vma_prot) | |
254 | { | |
255 | return 1; | |
256 | } | |
257 | ||
44ac8413 BH |
258 | #ifndef __HAVE_PHYS_MEM_ACCESS_PROT |
259 | static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, | |
260 | unsigned long size, pgprot_t vma_prot) | |
261 | { | |
262 | #ifdef pgprot_noncached | |
263 | unsigned long offset = pfn << PAGE_SHIFT; | |
264 | ||
265 | if (uncached_access(file, offset)) | |
266 | return pgprot_noncached(vma_prot); | |
267 | #endif | |
268 | return vma_prot; | |
269 | } | |
270 | #endif | |
271 | ||
5da6185b DH |
272 | #ifndef CONFIG_MMU |
273 | static unsigned long get_unmapped_area_mem(struct file *file, | |
274 | unsigned long addr, | |
275 | unsigned long len, | |
276 | unsigned long pgoff, | |
277 | unsigned long flags) | |
278 | { | |
279 | if (!valid_mmap_phys_addr_range(pgoff, len)) | |
280 | return (unsigned long) -EINVAL; | |
8a93258c | 281 | return pgoff << PAGE_SHIFT; |
5da6185b DH |
282 | } |
283 | ||
284 | /* can't do an in-place private mapping if there's no MMU */ | |
285 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
286 | { | |
287 | return vma->vm_flags & VM_MAYSHARE; | |
288 | } | |
289 | #else | |
290 | #define get_unmapped_area_mem NULL | |
291 | ||
292 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
293 | { | |
294 | return 1; | |
295 | } | |
296 | #endif | |
297 | ||
f0f37e2f | 298 | static const struct vm_operations_struct mmap_mem_ops = { |
7ae8ed50 RR |
299 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
300 | .access = generic_access_phys | |
301 | #endif | |
e7f260a2 | 302 | }; |
303 | ||
1da177e4 LT |
304 | static int mmap_mem(struct file * file, struct vm_area_struct * vma) |
305 | { | |
80851ef2 BH |
306 | size_t size = vma->vm_end - vma->vm_start; |
307 | ||
06c67bef | 308 | if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) |
80851ef2 BH |
309 | return -EINVAL; |
310 | ||
5da6185b DH |
311 | if (!private_mapping_ok(vma)) |
312 | return -ENOSYS; | |
313 | ||
e2beb3ea VP |
314 | if (!range_is_allowed(vma->vm_pgoff, size)) |
315 | return -EPERM; | |
316 | ||
f0970c13 | 317 | if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, |
318 | &vma->vm_page_prot)) | |
319 | return -EINVAL; | |
320 | ||
8b150478 | 321 | vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, |
80851ef2 | 322 | size, |
1da177e4 | 323 | vma->vm_page_prot); |
1da177e4 | 324 | |
e7f260a2 | 325 | vma->vm_ops = &mmap_mem_ops; |
326 | ||
1da177e4 LT |
327 | /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ |
328 | if (remap_pfn_range(vma, | |
329 | vma->vm_start, | |
330 | vma->vm_pgoff, | |
80851ef2 | 331 | size, |
e7f260a2 | 332 | vma->vm_page_prot)) { |
1da177e4 | 333 | return -EAGAIN; |
e7f260a2 | 334 | } |
1da177e4 LT |
335 | return 0; |
336 | } | |
337 | ||
b781ecb6 | 338 | #ifdef CONFIG_DEVKMEM |
1da177e4 LT |
339 | static int mmap_kmem(struct file * file, struct vm_area_struct * vma) |
340 | { | |
4bb82551 LT |
341 | unsigned long pfn; |
342 | ||
6d3154cc LT |
343 | /* Turn a kernel-virtual address into a physical page frame */ |
344 | pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; | |
4bb82551 | 345 | |
1da177e4 LT |
346 | /* |
347 | * RED-PEN: on some architectures there is more mapped memory | |
348 | * than available in mem_map which pfn_valid checks | |
349 | * for. Perhaps should add a new macro here. | |
350 | * | |
351 | * RED-PEN: vmalloc is not supported right now. | |
352 | */ | |
4bb82551 | 353 | if (!pfn_valid(pfn)) |
1da177e4 | 354 | return -EIO; |
4bb82551 LT |
355 | |
356 | vma->vm_pgoff = pfn; | |
1da177e4 LT |
357 | return mmap_mem(file, vma); |
358 | } | |
b781ecb6 | 359 | #endif |
1da177e4 | 360 | |
50b1fdbd VG |
361 | #ifdef CONFIG_CRASH_DUMP |
362 | /* | |
363 | * Read memory corresponding to the old kernel. | |
50b1fdbd | 364 | */ |
315c215c | 365 | static ssize_t read_oldmem(struct file *file, char __user *buf, |
50b1fdbd VG |
366 | size_t count, loff_t *ppos) |
367 | { | |
315c215c VG |
368 | unsigned long pfn, offset; |
369 | size_t read = 0, csize; | |
370 | int rc = 0; | |
50b1fdbd | 371 | |
72414d3f | 372 | while (count) { |
50b1fdbd | 373 | pfn = *ppos / PAGE_SIZE; |
315c215c VG |
374 | if (pfn > saved_max_pfn) |
375 | return read; | |
50b1fdbd | 376 | |
315c215c VG |
377 | offset = (unsigned long)(*ppos % PAGE_SIZE); |
378 | if (count > PAGE_SIZE - offset) | |
379 | csize = PAGE_SIZE - offset; | |
380 | else | |
381 | csize = count; | |
50b1fdbd | 382 | |
315c215c VG |
383 | rc = copy_oldmem_page(pfn, buf, csize, offset, 1); |
384 | if (rc < 0) | |
385 | return rc; | |
50b1fdbd VG |
386 | buf += csize; |
387 | *ppos += csize; | |
388 | read += csize; | |
389 | count -= csize; | |
390 | } | |
50b1fdbd VG |
391 | return read; |
392 | } | |
393 | #endif | |
1da177e4 | 394 | |
b781ecb6 | 395 | #ifdef CONFIG_DEVKMEM |
1da177e4 LT |
396 | /* |
397 | * This function reads the *virtual* memory as seen by the kernel. | |
398 | */ | |
399 | static ssize_t read_kmem(struct file *file, char __user *buf, | |
400 | size_t count, loff_t *ppos) | |
401 | { | |
402 | unsigned long p = *ppos; | |
403 | ssize_t low_count, read, sz; | |
404 | char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ | |
405 | ||
406 | read = 0; | |
407 | if (p < (unsigned long) high_memory) { | |
408 | low_count = count; | |
409 | if (count > (unsigned long) high_memory - p) | |
410 | low_count = (unsigned long) high_memory - p; | |
411 | ||
412 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
413 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
414 | if (p < PAGE_SIZE && low_count > 0) { | |
415 | size_t tmp = PAGE_SIZE - p; | |
416 | if (tmp > low_count) tmp = low_count; | |
417 | if (clear_user(buf, tmp)) | |
418 | return -EFAULT; | |
419 | buf += tmp; | |
420 | p += tmp; | |
421 | read += tmp; | |
422 | low_count -= tmp; | |
423 | count -= tmp; | |
424 | } | |
425 | #endif | |
426 | while (low_count > 0) { | |
f222318e | 427 | sz = size_inside_page(p, low_count); |
1da177e4 LT |
428 | |
429 | /* | |
430 | * On ia64 if a page has been mapped somewhere as | |
431 | * uncached, then it must also be accessed uncached | |
432 | * by the kernel or data corruption may occur | |
433 | */ | |
434 | kbuf = xlate_dev_kmem_ptr((char *)p); | |
435 | ||
436 | if (copy_to_user(buf, kbuf, sz)) | |
437 | return -EFAULT; | |
438 | buf += sz; | |
439 | p += sz; | |
440 | read += sz; | |
441 | low_count -= sz; | |
442 | count -= sz; | |
443 | } | |
444 | } | |
445 | ||
446 | if (count > 0) { | |
447 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
448 | if (!kbuf) | |
449 | return -ENOMEM; | |
450 | while (count > 0) { | |
f222318e | 451 | int len = size_inside_page(p, count); |
1da177e4 | 452 | |
1da177e4 LT |
453 | len = vread(kbuf, (char *)p, len); |
454 | if (!len) | |
455 | break; | |
456 | if (copy_to_user(buf, kbuf, len)) { | |
457 | free_page((unsigned long)kbuf); | |
458 | return -EFAULT; | |
459 | } | |
460 | count -= len; | |
461 | buf += len; | |
462 | read += len; | |
463 | p += len; | |
464 | } | |
465 | free_page((unsigned long)kbuf); | |
466 | } | |
467 | *ppos = p; | |
468 | return read; | |
469 | } | |
470 | ||
471 | ||
472 | static inline ssize_t | |
473 | do_write_kmem(void *p, unsigned long realp, const char __user * buf, | |
474 | size_t count, loff_t *ppos) | |
475 | { | |
476 | ssize_t written, sz; | |
477 | unsigned long copied; | |
478 | ||
479 | written = 0; | |
480 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
481 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
482 | if (realp < PAGE_SIZE) { | |
483 | unsigned long sz = PAGE_SIZE - realp; | |
484 | if (sz > count) | |
485 | sz = count; | |
486 | /* Hmm. Do something? */ | |
487 | buf += sz; | |
488 | p += sz; | |
489 | realp += sz; | |
490 | count -= sz; | |
491 | written += sz; | |
492 | } | |
493 | #endif | |
494 | ||
495 | while (count > 0) { | |
496 | char *ptr; | |
1da177e4 | 497 | |
f222318e | 498 | sz = size_inside_page(realp, count); |
1da177e4 LT |
499 | |
500 | /* | |
501 | * On ia64 if a page has been mapped somewhere as | |
502 | * uncached, then it must also be accessed uncached | |
503 | * by the kernel or data corruption may occur | |
504 | */ | |
505 | ptr = xlate_dev_kmem_ptr(p); | |
506 | ||
507 | copied = copy_from_user(ptr, buf, sz); | |
508 | if (copied) { | |
c654d60e JB |
509 | written += sz - copied; |
510 | if (written) | |
511 | break; | |
1da177e4 LT |
512 | return -EFAULT; |
513 | } | |
514 | buf += sz; | |
515 | p += sz; | |
516 | realp += sz; | |
517 | count -= sz; | |
518 | written += sz; | |
519 | } | |
520 | ||
521 | *ppos += written; | |
522 | return written; | |
523 | } | |
524 | ||
525 | ||
526 | /* | |
527 | * This function writes to the *virtual* memory as seen by the kernel. | |
528 | */ | |
529 | static ssize_t write_kmem(struct file * file, const char __user * buf, | |
530 | size_t count, loff_t *ppos) | |
531 | { | |
532 | unsigned long p = *ppos; | |
533 | ssize_t wrote = 0; | |
534 | ssize_t virtr = 0; | |
535 | ssize_t written; | |
536 | char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ | |
537 | ||
538 | if (p < (unsigned long) high_memory) { | |
539 | ||
540 | wrote = count; | |
541 | if (count > (unsigned long) high_memory - p) | |
542 | wrote = (unsigned long) high_memory - p; | |
543 | ||
544 | written = do_write_kmem((void*)p, p, buf, wrote, ppos); | |
545 | if (written != wrote) | |
546 | return written; | |
547 | wrote = written; | |
548 | p += wrote; | |
549 | buf += wrote; | |
550 | count -= wrote; | |
551 | } | |
552 | ||
553 | if (count > 0) { | |
554 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
555 | if (!kbuf) | |
556 | return wrote ? wrote : -ENOMEM; | |
557 | while (count > 0) { | |
f222318e | 558 | int len = size_inside_page(p, count); |
1da177e4 | 559 | |
4ea2f43f WF |
560 | written = copy_from_user(kbuf, buf, len); |
561 | if (written) { | |
562 | if (wrote + virtr) | |
563 | break; | |
564 | free_page((unsigned long)kbuf); | |
565 | return -EFAULT; | |
1da177e4 LT |
566 | } |
567 | len = vwrite(kbuf, (char *)p, len); | |
568 | count -= len; | |
569 | buf += len; | |
570 | virtr += len; | |
571 | p += len; | |
572 | } | |
573 | free_page((unsigned long)kbuf); | |
574 | } | |
575 | ||
576 | *ppos = p; | |
577 | return virtr + wrote; | |
578 | } | |
b781ecb6 | 579 | #endif |
1da177e4 | 580 | |
4f911d64 | 581 | #ifdef CONFIG_DEVPORT |
1da177e4 LT |
582 | static ssize_t read_port(struct file * file, char __user * buf, |
583 | size_t count, loff_t *ppos) | |
584 | { | |
585 | unsigned long i = *ppos; | |
586 | char __user *tmp = buf; | |
587 | ||
588 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
589 | return -EFAULT; | |
590 | while (count-- > 0 && i < 65536) { | |
591 | if (__put_user(inb(i),tmp) < 0) | |
592 | return -EFAULT; | |
593 | i++; | |
594 | tmp++; | |
595 | } | |
596 | *ppos = i; | |
597 | return tmp-buf; | |
598 | } | |
599 | ||
600 | static ssize_t write_port(struct file * file, const char __user * buf, | |
601 | size_t count, loff_t *ppos) | |
602 | { | |
603 | unsigned long i = *ppos; | |
604 | const char __user * tmp = buf; | |
605 | ||
606 | if (!access_ok(VERIFY_READ,buf,count)) | |
607 | return -EFAULT; | |
608 | while (count-- > 0 && i < 65536) { | |
609 | char c; | |
c654d60e JB |
610 | if (__get_user(c, tmp)) { |
611 | if (tmp > buf) | |
612 | break; | |
1da177e4 | 613 | return -EFAULT; |
c654d60e | 614 | } |
1da177e4 LT |
615 | outb(c,i); |
616 | i++; | |
617 | tmp++; | |
618 | } | |
619 | *ppos = i; | |
620 | return tmp-buf; | |
621 | } | |
622 | #endif | |
623 | ||
624 | static ssize_t read_null(struct file * file, char __user * buf, | |
625 | size_t count, loff_t *ppos) | |
626 | { | |
627 | return 0; | |
628 | } | |
629 | ||
630 | static ssize_t write_null(struct file * file, const char __user * buf, | |
631 | size_t count, loff_t *ppos) | |
632 | { | |
633 | return count; | |
634 | } | |
635 | ||
1ebd32fc JA |
636 | static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, |
637 | struct splice_desc *sd) | |
638 | { | |
639 | return sd->len; | |
640 | } | |
641 | ||
642 | static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out, | |
643 | loff_t *ppos, size_t len, unsigned int flags) | |
644 | { | |
645 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); | |
646 | } | |
647 | ||
1da177e4 LT |
648 | static ssize_t read_zero(struct file * file, char __user * buf, |
649 | size_t count, loff_t *ppos) | |
650 | { | |
557ed1fa | 651 | size_t written; |
1da177e4 LT |
652 | |
653 | if (!count) | |
654 | return 0; | |
655 | ||
656 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
657 | return -EFAULT; | |
658 | ||
557ed1fa NP |
659 | written = 0; |
660 | while (count) { | |
661 | unsigned long unwritten; | |
662 | size_t chunk = count; | |
1da177e4 | 663 | |
557ed1fa NP |
664 | if (chunk > PAGE_SIZE) |
665 | chunk = PAGE_SIZE; /* Just for latency reasons */ | |
bb521c5d | 666 | unwritten = __clear_user(buf, chunk); |
557ed1fa | 667 | written += chunk - unwritten; |
1da177e4 | 668 | if (unwritten) |
557ed1fa | 669 | break; |
2b838687 LT |
670 | if (signal_pending(current)) |
671 | return written ? written : -ERESTARTSYS; | |
1da177e4 | 672 | buf += chunk; |
557ed1fa | 673 | count -= chunk; |
1da177e4 LT |
674 | cond_resched(); |
675 | } | |
557ed1fa | 676 | return written ? written : -EFAULT; |
1da177e4 LT |
677 | } |
678 | ||
679 | static int mmap_zero(struct file * file, struct vm_area_struct * vma) | |
680 | { | |
557ed1fa | 681 | #ifndef CONFIG_MMU |
1da177e4 | 682 | return -ENOSYS; |
557ed1fa NP |
683 | #endif |
684 | if (vma->vm_flags & VM_SHARED) | |
685 | return shmem_zero_setup(vma); | |
686 | return 0; | |
1da177e4 | 687 | } |
1da177e4 LT |
688 | |
689 | static ssize_t write_full(struct file * file, const char __user * buf, | |
690 | size_t count, loff_t *ppos) | |
691 | { | |
692 | return -ENOSPC; | |
693 | } | |
694 | ||
695 | /* | |
696 | * Special lseek() function for /dev/null and /dev/zero. Most notably, you | |
697 | * can fopen() both devices with "a" now. This was previously impossible. | |
698 | * -- SRB. | |
699 | */ | |
700 | ||
701 | static loff_t null_lseek(struct file * file, loff_t offset, int orig) | |
702 | { | |
703 | return file->f_pos = 0; | |
704 | } | |
705 | ||
706 | /* | |
707 | * The memory devices use the full 32/64 bits of the offset, and so we cannot | |
708 | * check against negative addresses: they are ok. The return value is weird, | |
709 | * though, in that case (0). | |
710 | * | |
711 | * also note that seeking relative to the "end of file" isn't supported: | |
712 | * it has no meaning, so it returns -EINVAL. | |
713 | */ | |
714 | static loff_t memory_lseek(struct file * file, loff_t offset, int orig) | |
715 | { | |
716 | loff_t ret; | |
717 | ||
a7113a96 | 718 | mutex_lock(&file->f_path.dentry->d_inode->i_mutex); |
1da177e4 LT |
719 | switch (orig) { |
720 | case 0: | |
721 | file->f_pos = offset; | |
722 | ret = file->f_pos; | |
723 | force_successful_syscall_return(); | |
724 | break; | |
725 | case 1: | |
726 | file->f_pos += offset; | |
727 | ret = file->f_pos; | |
728 | force_successful_syscall_return(); | |
729 | break; | |
730 | default: | |
731 | ret = -EINVAL; | |
732 | } | |
a7113a96 | 733 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
1da177e4 LT |
734 | return ret; |
735 | } | |
736 | ||
737 | static int open_port(struct inode * inode, struct file * filp) | |
738 | { | |
739 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; | |
740 | } | |
741 | ||
742 | #define zero_lseek null_lseek | |
743 | #define full_lseek null_lseek | |
744 | #define write_zero write_null | |
745 | #define read_full read_zero | |
746 | #define open_mem open_port | |
747 | #define open_kmem open_mem | |
50b1fdbd | 748 | #define open_oldmem open_mem |
1da177e4 | 749 | |
62322d25 | 750 | static const struct file_operations mem_fops = { |
1da177e4 LT |
751 | .llseek = memory_lseek, |
752 | .read = read_mem, | |
753 | .write = write_mem, | |
754 | .mmap = mmap_mem, | |
755 | .open = open_mem, | |
5da6185b | 756 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 LT |
757 | }; |
758 | ||
b781ecb6 | 759 | #ifdef CONFIG_DEVKMEM |
62322d25 | 760 | static const struct file_operations kmem_fops = { |
1da177e4 LT |
761 | .llseek = memory_lseek, |
762 | .read = read_kmem, | |
763 | .write = write_kmem, | |
764 | .mmap = mmap_kmem, | |
765 | .open = open_kmem, | |
5da6185b | 766 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 | 767 | }; |
b781ecb6 | 768 | #endif |
1da177e4 | 769 | |
62322d25 | 770 | static const struct file_operations null_fops = { |
1da177e4 LT |
771 | .llseek = null_lseek, |
772 | .read = read_null, | |
773 | .write = write_null, | |
1ebd32fc | 774 | .splice_write = splice_write_null, |
1da177e4 LT |
775 | }; |
776 | ||
4f911d64 | 777 | #ifdef CONFIG_DEVPORT |
62322d25 | 778 | static const struct file_operations port_fops = { |
1da177e4 LT |
779 | .llseek = memory_lseek, |
780 | .read = read_port, | |
781 | .write = write_port, | |
782 | .open = open_port, | |
783 | }; | |
784 | #endif | |
785 | ||
62322d25 | 786 | static const struct file_operations zero_fops = { |
1da177e4 LT |
787 | .llseek = zero_lseek, |
788 | .read = read_zero, | |
789 | .write = write_zero, | |
790 | .mmap = mmap_zero, | |
791 | }; | |
792 | ||
5da6185b DH |
793 | /* |
794 | * capabilities for /dev/zero | |
795 | * - permits private mappings, "copies" are taken of the source of zeros | |
796 | */ | |
1da177e4 | 797 | static struct backing_dev_info zero_bdi = { |
d993831f | 798 | .name = "char/mem", |
1da177e4 LT |
799 | .capabilities = BDI_CAP_MAP_COPY, |
800 | }; | |
801 | ||
62322d25 | 802 | static const struct file_operations full_fops = { |
1da177e4 LT |
803 | .llseek = full_lseek, |
804 | .read = read_full, | |
805 | .write = write_full, | |
806 | }; | |
807 | ||
50b1fdbd | 808 | #ifdef CONFIG_CRASH_DUMP |
62322d25 | 809 | static const struct file_operations oldmem_fops = { |
50b1fdbd VG |
810 | .read = read_oldmem, |
811 | .open = open_oldmem, | |
812 | }; | |
813 | #endif | |
814 | ||
1da177e4 LT |
815 | static ssize_t kmsg_write(struct file * file, const char __user * buf, |
816 | size_t count, loff_t *ppos) | |
817 | { | |
818 | char *tmp; | |
cd140a5c | 819 | ssize_t ret; |
1da177e4 LT |
820 | |
821 | tmp = kmalloc(count + 1, GFP_KERNEL); | |
822 | if (tmp == NULL) | |
823 | return -ENOMEM; | |
824 | ret = -EFAULT; | |
825 | if (!copy_from_user(tmp, buf, count)) { | |
826 | tmp[count] = 0; | |
827 | ret = printk("%s", tmp); | |
cd140a5c GC |
828 | if (ret > count) |
829 | /* printk can add a prefix */ | |
830 | ret = count; | |
1da177e4 LT |
831 | } |
832 | kfree(tmp); | |
833 | return ret; | |
834 | } | |
835 | ||
62322d25 | 836 | static const struct file_operations kmsg_fops = { |
1da177e4 LT |
837 | .write = kmsg_write, |
838 | }; | |
839 | ||
389e0cb9 KS |
840 | static const struct memdev { |
841 | const char *name; | |
e454cea2 | 842 | mode_t mode; |
389e0cb9 KS |
843 | const struct file_operations *fops; |
844 | struct backing_dev_info *dev_info; | |
845 | } devlist[] = { | |
e454cea2 | 846 | [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi }, |
b781ecb6 | 847 | #ifdef CONFIG_DEVKMEM |
e454cea2 | 848 | [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi }, |
b781ecb6 | 849 | #endif |
e454cea2 | 850 | [3] = { "null", 0666, &null_fops, NULL }, |
4f911d64 | 851 | #ifdef CONFIG_DEVPORT |
e454cea2 | 852 | [4] = { "port", 0, &port_fops, NULL }, |
1da177e4 | 853 | #endif |
e454cea2 KS |
854 | [5] = { "zero", 0666, &zero_fops, &zero_bdi }, |
855 | [7] = { "full", 0666, &full_fops, NULL }, | |
856 | [8] = { "random", 0666, &random_fops, NULL }, | |
857 | [9] = { "urandom", 0666, &urandom_fops, NULL }, | |
858 | [11] = { "kmsg", 0, &kmsg_fops, NULL }, | |
50b1fdbd | 859 | #ifdef CONFIG_CRASH_DUMP |
e454cea2 | 860 | [12] = { "oldmem", 0, &oldmem_fops, NULL }, |
50b1fdbd | 861 | #endif |
d6f47bef ASF |
862 | }; |
863 | ||
864 | static int memory_open(struct inode *inode, struct file *filp) | |
865 | { | |
389e0cb9 KS |
866 | int minor; |
867 | const struct memdev *dev; | |
d6f47bef | 868 | |
389e0cb9 KS |
869 | minor = iminor(inode); |
870 | if (minor >= ARRAY_SIZE(devlist)) | |
205153aa | 871 | return -ENXIO; |
d6f47bef | 872 | |
389e0cb9 KS |
873 | dev = &devlist[minor]; |
874 | if (!dev->fops) | |
205153aa | 875 | return -ENXIO; |
d6f47bef | 876 | |
389e0cb9 KS |
877 | filp->f_op = dev->fops; |
878 | if (dev->dev_info) | |
879 | filp->f_mapping->backing_dev_info = dev->dev_info; | |
d6f47bef | 880 | |
389e0cb9 | 881 | if (dev->fops->open) |
205153aa FW |
882 | return dev->fops->open(inode, filp); |
883 | ||
884 | return 0; | |
1da177e4 LT |
885 | } |
886 | ||
62322d25 | 887 | static const struct file_operations memory_fops = { |
389e0cb9 | 888 | .open = memory_open, |
1da177e4 LT |
889 | }; |
890 | ||
e454cea2 KS |
891 | static char *mem_devnode(struct device *dev, mode_t *mode) |
892 | { | |
893 | if (mode && devlist[MINOR(dev->devt)].mode) | |
894 | *mode = devlist[MINOR(dev->devt)].mode; | |
895 | return NULL; | |
896 | } | |
897 | ||
ca8eca68 | 898 | static struct class *mem_class; |
1da177e4 LT |
899 | |
900 | static int __init chr_dev_init(void) | |
901 | { | |
389e0cb9 | 902 | int minor; |
e0bf68dd PZ |
903 | int err; |
904 | ||
905 | err = bdi_init(&zero_bdi); | |
906 | if (err) | |
907 | return err; | |
1da177e4 LT |
908 | |
909 | if (register_chrdev(MEM_MAJOR,"mem",&memory_fops)) | |
910 | printk("unable to get major %d for memory devs\n", MEM_MAJOR); | |
911 | ||
ca8eca68 | 912 | mem_class = class_create(THIS_MODULE, "mem"); |
e454cea2 | 913 | mem_class->devnode = mem_devnode; |
389e0cb9 KS |
914 | for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) { |
915 | if (!devlist[minor].name) | |
916 | continue; | |
917 | device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor), | |
918 | NULL, devlist[minor].name); | |
919 | } | |
ebf644c4 | 920 | |
1da177e4 LT |
921 | return 0; |
922 | } | |
923 | ||
924 | fs_initcall(chr_dev_init); |