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