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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 | * | |
6 | * Added devfs support. | |
7 | * Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu> | |
8 | * Shared /dev/zero mmaping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com> | |
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> | |
21 | #include <linux/smp_lock.h> | |
1da177e4 LT |
22 | #include <linux/ptrace.h> |
23 | #include <linux/device.h> | |
50b1fdbd VG |
24 | #include <linux/highmem.h> |
25 | #include <linux/crash_dump.h> | |
1da177e4 | 26 | #include <linux/backing-dev.h> |
315c215c | 27 | #include <linux/bootmem.h> |
1ebd32fc | 28 | #include <linux/pipe_fs_i.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 | ||
1da177e4 LT |
37 | /* |
38 | * Architectures vary in how they handle caching for addresses | |
39 | * outside of main memory. | |
40 | * | |
41 | */ | |
42 | static inline int uncached_access(struct file *file, unsigned long addr) | |
43 | { | |
44 | #if defined(__i386__) | |
45 | /* | |
46 | * On the PPro and successors, the MTRRs are used to set | |
47 | * memory types for physical addresses outside main memory, | |
48 | * so blindly setting PCD or PWT on those pages is wrong. | |
49 | * For Pentiums and earlier, the surround logic should disable | |
50 | * caching for the high addresses through the KEN pin, but | |
51 | * we maintain the tradition of paranoia in this code. | |
52 | */ | |
53 | if (file->f_flags & O_SYNC) | |
54 | return 1; | |
55 | return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) || | |
56 | test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) || | |
57 | test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) || | |
58 | test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) ) | |
59 | && addr >= __pa(high_memory); | |
60 | #elif defined(__x86_64__) | |
61 | /* | |
62 | * This is broken because it can generate memory type aliases, | |
63 | * which can cause cache corruptions | |
64 | * But it is only available for root and we have to be bug-to-bug | |
65 | * compatible with i386. | |
66 | */ | |
67 | if (file->f_flags & O_SYNC) | |
68 | return 1; | |
69 | /* same behaviour as i386. PAT always set to cached and MTRRs control the | |
70 | caching behaviour. | |
71 | Hopefully a full PAT implementation will fix that soon. */ | |
72 | return 0; | |
73 | #elif defined(CONFIG_IA64) | |
74 | /* | |
75 | * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases. | |
76 | */ | |
77 | return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); | |
78 | #else | |
79 | /* | |
80 | * Accessing memory above the top the kernel knows about or through a file pointer | |
81 | * that was marked O_SYNC will be done non-cached. | |
82 | */ | |
83 | if (file->f_flags & O_SYNC) | |
84 | return 1; | |
85 | return addr >= __pa(high_memory); | |
86 | #endif | |
87 | } | |
88 | ||
89 | #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE | |
136939a2 | 90 | static inline int valid_phys_addr_range(unsigned long addr, size_t count) |
1da177e4 | 91 | { |
136939a2 | 92 | if (addr + count > __pa(high_memory)) |
1da177e4 LT |
93 | return 0; |
94 | ||
1da177e4 LT |
95 | return 1; |
96 | } | |
80851ef2 | 97 | |
06c67bef | 98 | static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) |
80851ef2 BH |
99 | { |
100 | return 1; | |
101 | } | |
1da177e4 LT |
102 | #endif |
103 | ||
104 | /* | |
105 | * This funcion reads the *physical* memory. The f_pos points directly to the | |
106 | * memory location. | |
107 | */ | |
108 | static ssize_t read_mem(struct file * file, char __user * buf, | |
109 | size_t count, loff_t *ppos) | |
110 | { | |
111 | unsigned long p = *ppos; | |
112 | ssize_t read, sz; | |
113 | char *ptr; | |
114 | ||
136939a2 | 115 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
116 | return -EFAULT; |
117 | read = 0; | |
118 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
119 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
120 | if (p < PAGE_SIZE) { | |
121 | sz = PAGE_SIZE - p; | |
122 | if (sz > count) | |
123 | sz = count; | |
124 | if (sz > 0) { | |
125 | if (clear_user(buf, sz)) | |
126 | return -EFAULT; | |
127 | buf += sz; | |
128 | p += sz; | |
129 | count -= sz; | |
130 | read += sz; | |
131 | } | |
132 | } | |
133 | #endif | |
134 | ||
135 | while (count > 0) { | |
136 | /* | |
137 | * Handle first page in case it's not aligned | |
138 | */ | |
139 | if (-p & (PAGE_SIZE - 1)) | |
140 | sz = -p & (PAGE_SIZE - 1); | |
141 | else | |
142 | sz = PAGE_SIZE; | |
143 | ||
144 | sz = min_t(unsigned long, sz, count); | |
145 | ||
146 | /* | |
147 | * On ia64 if a page has been mapped somewhere as | |
148 | * uncached, then it must also be accessed uncached | |
149 | * by the kernel or data corruption may occur | |
150 | */ | |
151 | ptr = xlate_dev_mem_ptr(p); | |
152 | ||
153 | if (copy_to_user(buf, ptr, sz)) | |
154 | return -EFAULT; | |
155 | buf += sz; | |
156 | p += sz; | |
157 | count -= sz; | |
158 | read += sz; | |
159 | } | |
160 | ||
161 | *ppos += read; | |
162 | return read; | |
163 | } | |
164 | ||
165 | static ssize_t write_mem(struct file * file, const char __user * buf, | |
166 | size_t count, loff_t *ppos) | |
167 | { | |
168 | unsigned long p = *ppos; | |
169 | ssize_t written, sz; | |
170 | unsigned long copied; | |
171 | void *ptr; | |
172 | ||
136939a2 | 173 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
174 | return -EFAULT; |
175 | ||
176 | written = 0; | |
177 | ||
178 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
179 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
180 | if (p < PAGE_SIZE) { | |
181 | unsigned long sz = PAGE_SIZE - p; | |
182 | if (sz > count) | |
183 | sz = count; | |
184 | /* Hmm. Do something? */ | |
185 | buf += sz; | |
186 | p += sz; | |
187 | count -= sz; | |
188 | written += sz; | |
189 | } | |
190 | #endif | |
191 | ||
192 | while (count > 0) { | |
193 | /* | |
194 | * Handle first page in case it's not aligned | |
195 | */ | |
196 | if (-p & (PAGE_SIZE - 1)) | |
197 | sz = -p & (PAGE_SIZE - 1); | |
198 | else | |
199 | sz = PAGE_SIZE; | |
200 | ||
201 | sz = min_t(unsigned long, sz, count); | |
202 | ||
203 | /* | |
204 | * On ia64 if a page has been mapped somewhere as | |
205 | * uncached, then it must also be accessed uncached | |
206 | * by the kernel or data corruption may occur | |
207 | */ | |
208 | ptr = xlate_dev_mem_ptr(p); | |
209 | ||
210 | copied = copy_from_user(ptr, buf, sz); | |
211 | if (copied) { | |
c654d60e JB |
212 | written += sz - copied; |
213 | if (written) | |
214 | break; | |
1da177e4 LT |
215 | return -EFAULT; |
216 | } | |
217 | buf += sz; | |
218 | p += sz; | |
219 | count -= sz; | |
220 | written += sz; | |
221 | } | |
222 | ||
223 | *ppos += written; | |
224 | return written; | |
225 | } | |
226 | ||
44ac8413 BH |
227 | #ifndef __HAVE_PHYS_MEM_ACCESS_PROT |
228 | static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, | |
229 | unsigned long size, pgprot_t vma_prot) | |
230 | { | |
231 | #ifdef pgprot_noncached | |
232 | unsigned long offset = pfn << PAGE_SHIFT; | |
233 | ||
234 | if (uncached_access(file, offset)) | |
235 | return pgprot_noncached(vma_prot); | |
236 | #endif | |
237 | return vma_prot; | |
238 | } | |
239 | #endif | |
240 | ||
1da177e4 LT |
241 | static int mmap_mem(struct file * file, struct vm_area_struct * vma) |
242 | { | |
80851ef2 BH |
243 | size_t size = vma->vm_end - vma->vm_start; |
244 | ||
06c67bef | 245 | if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) |
80851ef2 BH |
246 | return -EINVAL; |
247 | ||
8b150478 | 248 | vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, |
80851ef2 | 249 | size, |
1da177e4 | 250 | vma->vm_page_prot); |
1da177e4 LT |
251 | |
252 | /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ | |
253 | if (remap_pfn_range(vma, | |
254 | vma->vm_start, | |
255 | vma->vm_pgoff, | |
80851ef2 | 256 | size, |
1da177e4 LT |
257 | vma->vm_page_prot)) |
258 | return -EAGAIN; | |
259 | return 0; | |
260 | } | |
261 | ||
262 | static int mmap_kmem(struct file * file, struct vm_area_struct * vma) | |
263 | { | |
4bb82551 LT |
264 | unsigned long pfn; |
265 | ||
266 | /* Turn a kernel-virtual address into a physical page frame */ | |
267 | pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; | |
268 | ||
1da177e4 LT |
269 | /* |
270 | * RED-PEN: on some architectures there is more mapped memory | |
271 | * than available in mem_map which pfn_valid checks | |
272 | * for. Perhaps should add a new macro here. | |
273 | * | |
274 | * RED-PEN: vmalloc is not supported right now. | |
275 | */ | |
4bb82551 | 276 | if (!pfn_valid(pfn)) |
1da177e4 | 277 | return -EIO; |
4bb82551 LT |
278 | |
279 | vma->vm_pgoff = pfn; | |
1da177e4 LT |
280 | return mmap_mem(file, vma); |
281 | } | |
282 | ||
50b1fdbd VG |
283 | #ifdef CONFIG_CRASH_DUMP |
284 | /* | |
285 | * Read memory corresponding to the old kernel. | |
50b1fdbd | 286 | */ |
315c215c | 287 | static ssize_t read_oldmem(struct file *file, char __user *buf, |
50b1fdbd VG |
288 | size_t count, loff_t *ppos) |
289 | { | |
315c215c VG |
290 | unsigned long pfn, offset; |
291 | size_t read = 0, csize; | |
292 | int rc = 0; | |
50b1fdbd | 293 | |
72414d3f | 294 | while (count) { |
50b1fdbd | 295 | pfn = *ppos / PAGE_SIZE; |
315c215c VG |
296 | if (pfn > saved_max_pfn) |
297 | return read; | |
50b1fdbd | 298 | |
315c215c VG |
299 | offset = (unsigned long)(*ppos % PAGE_SIZE); |
300 | if (count > PAGE_SIZE - offset) | |
301 | csize = PAGE_SIZE - offset; | |
302 | else | |
303 | csize = count; | |
50b1fdbd | 304 | |
315c215c VG |
305 | rc = copy_oldmem_page(pfn, buf, csize, offset, 1); |
306 | if (rc < 0) | |
307 | return rc; | |
50b1fdbd VG |
308 | buf += csize; |
309 | *ppos += csize; | |
310 | read += csize; | |
311 | count -= csize; | |
312 | } | |
50b1fdbd VG |
313 | return read; |
314 | } | |
315 | #endif | |
316 | ||
1da177e4 LT |
317 | extern long vread(char *buf, char *addr, unsigned long count); |
318 | extern long vwrite(char *buf, char *addr, unsigned long count); | |
319 | ||
320 | /* | |
321 | * This function reads the *virtual* memory as seen by the kernel. | |
322 | */ | |
323 | static ssize_t read_kmem(struct file *file, char __user *buf, | |
324 | size_t count, loff_t *ppos) | |
325 | { | |
326 | unsigned long p = *ppos; | |
327 | ssize_t low_count, read, sz; | |
328 | char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ | |
329 | ||
330 | read = 0; | |
331 | if (p < (unsigned long) high_memory) { | |
332 | low_count = count; | |
333 | if (count > (unsigned long) high_memory - p) | |
334 | low_count = (unsigned long) high_memory - p; | |
335 | ||
336 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
337 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
338 | if (p < PAGE_SIZE && low_count > 0) { | |
339 | size_t tmp = PAGE_SIZE - p; | |
340 | if (tmp > low_count) tmp = low_count; | |
341 | if (clear_user(buf, tmp)) | |
342 | return -EFAULT; | |
343 | buf += tmp; | |
344 | p += tmp; | |
345 | read += tmp; | |
346 | low_count -= tmp; | |
347 | count -= tmp; | |
348 | } | |
349 | #endif | |
350 | while (low_count > 0) { | |
351 | /* | |
352 | * Handle first page in case it's not aligned | |
353 | */ | |
354 | if (-p & (PAGE_SIZE - 1)) | |
355 | sz = -p & (PAGE_SIZE - 1); | |
356 | else | |
357 | sz = PAGE_SIZE; | |
358 | ||
359 | sz = min_t(unsigned long, sz, low_count); | |
360 | ||
361 | /* | |
362 | * On ia64 if a page has been mapped somewhere as | |
363 | * uncached, then it must also be accessed uncached | |
364 | * by the kernel or data corruption may occur | |
365 | */ | |
366 | kbuf = xlate_dev_kmem_ptr((char *)p); | |
367 | ||
368 | if (copy_to_user(buf, kbuf, sz)) | |
369 | return -EFAULT; | |
370 | buf += sz; | |
371 | p += sz; | |
372 | read += sz; | |
373 | low_count -= sz; | |
374 | count -= sz; | |
375 | } | |
376 | } | |
377 | ||
378 | if (count > 0) { | |
379 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
380 | if (!kbuf) | |
381 | return -ENOMEM; | |
382 | while (count > 0) { | |
383 | int len = count; | |
384 | ||
385 | if (len > PAGE_SIZE) | |
386 | len = PAGE_SIZE; | |
387 | len = vread(kbuf, (char *)p, len); | |
388 | if (!len) | |
389 | break; | |
390 | if (copy_to_user(buf, kbuf, len)) { | |
391 | free_page((unsigned long)kbuf); | |
392 | return -EFAULT; | |
393 | } | |
394 | count -= len; | |
395 | buf += len; | |
396 | read += len; | |
397 | p += len; | |
398 | } | |
399 | free_page((unsigned long)kbuf); | |
400 | } | |
401 | *ppos = p; | |
402 | return read; | |
403 | } | |
404 | ||
405 | ||
406 | static inline ssize_t | |
407 | do_write_kmem(void *p, unsigned long realp, const char __user * buf, | |
408 | size_t count, loff_t *ppos) | |
409 | { | |
410 | ssize_t written, sz; | |
411 | unsigned long copied; | |
412 | ||
413 | written = 0; | |
414 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
415 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
416 | if (realp < PAGE_SIZE) { | |
417 | unsigned long sz = PAGE_SIZE - realp; | |
418 | if (sz > count) | |
419 | sz = count; | |
420 | /* Hmm. Do something? */ | |
421 | buf += sz; | |
422 | p += sz; | |
423 | realp += sz; | |
424 | count -= sz; | |
425 | written += sz; | |
426 | } | |
427 | #endif | |
428 | ||
429 | while (count > 0) { | |
430 | char *ptr; | |
431 | /* | |
432 | * Handle first page in case it's not aligned | |
433 | */ | |
434 | if (-realp & (PAGE_SIZE - 1)) | |
435 | sz = -realp & (PAGE_SIZE - 1); | |
436 | else | |
437 | sz = PAGE_SIZE; | |
438 | ||
439 | sz = min_t(unsigned long, sz, count); | |
440 | ||
441 | /* | |
442 | * On ia64 if a page has been mapped somewhere as | |
443 | * uncached, then it must also be accessed uncached | |
444 | * by the kernel or data corruption may occur | |
445 | */ | |
446 | ptr = xlate_dev_kmem_ptr(p); | |
447 | ||
448 | copied = copy_from_user(ptr, buf, sz); | |
449 | if (copied) { | |
c654d60e JB |
450 | written += sz - copied; |
451 | if (written) | |
452 | break; | |
1da177e4 LT |
453 | return -EFAULT; |
454 | } | |
455 | buf += sz; | |
456 | p += sz; | |
457 | realp += sz; | |
458 | count -= sz; | |
459 | written += sz; | |
460 | } | |
461 | ||
462 | *ppos += written; | |
463 | return written; | |
464 | } | |
465 | ||
466 | ||
467 | /* | |
468 | * This function writes to the *virtual* memory as seen by the kernel. | |
469 | */ | |
470 | static ssize_t write_kmem(struct file * file, const char __user * buf, | |
471 | size_t count, loff_t *ppos) | |
472 | { | |
473 | unsigned long p = *ppos; | |
474 | ssize_t wrote = 0; | |
475 | ssize_t virtr = 0; | |
476 | ssize_t written; | |
477 | char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ | |
478 | ||
479 | if (p < (unsigned long) high_memory) { | |
480 | ||
481 | wrote = count; | |
482 | if (count > (unsigned long) high_memory - p) | |
483 | wrote = (unsigned long) high_memory - p; | |
484 | ||
485 | written = do_write_kmem((void*)p, p, buf, wrote, ppos); | |
486 | if (written != wrote) | |
487 | return written; | |
488 | wrote = written; | |
489 | p += wrote; | |
490 | buf += wrote; | |
491 | count -= wrote; | |
492 | } | |
493 | ||
494 | if (count > 0) { | |
495 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
496 | if (!kbuf) | |
497 | return wrote ? wrote : -ENOMEM; | |
498 | while (count > 0) { | |
499 | int len = count; | |
500 | ||
501 | if (len > PAGE_SIZE) | |
502 | len = PAGE_SIZE; | |
503 | if (len) { | |
504 | written = copy_from_user(kbuf, buf, len); | |
505 | if (written) { | |
c654d60e JB |
506 | if (wrote + virtr) |
507 | break; | |
1da177e4 | 508 | free_page((unsigned long)kbuf); |
c654d60e | 509 | return -EFAULT; |
1da177e4 LT |
510 | } |
511 | } | |
512 | len = vwrite(kbuf, (char *)p, len); | |
513 | count -= len; | |
514 | buf += len; | |
515 | virtr += len; | |
516 | p += len; | |
517 | } | |
518 | free_page((unsigned long)kbuf); | |
519 | } | |
520 | ||
521 | *ppos = p; | |
522 | return virtr + wrote; | |
523 | } | |
524 | ||
ee2cdece | 525 | #if defined(CONFIG_ISA) || !defined(__mc68000__) |
1da177e4 LT |
526 | static ssize_t read_port(struct file * file, char __user * buf, |
527 | size_t count, loff_t *ppos) | |
528 | { | |
529 | unsigned long i = *ppos; | |
530 | char __user *tmp = buf; | |
531 | ||
532 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
533 | return -EFAULT; | |
534 | while (count-- > 0 && i < 65536) { | |
535 | if (__put_user(inb(i),tmp) < 0) | |
536 | return -EFAULT; | |
537 | i++; | |
538 | tmp++; | |
539 | } | |
540 | *ppos = i; | |
541 | return tmp-buf; | |
542 | } | |
543 | ||
544 | static ssize_t write_port(struct file * file, const char __user * buf, | |
545 | size_t count, loff_t *ppos) | |
546 | { | |
547 | unsigned long i = *ppos; | |
548 | const char __user * tmp = buf; | |
549 | ||
550 | if (!access_ok(VERIFY_READ,buf,count)) | |
551 | return -EFAULT; | |
552 | while (count-- > 0 && i < 65536) { | |
553 | char c; | |
c654d60e JB |
554 | if (__get_user(c, tmp)) { |
555 | if (tmp > buf) | |
556 | break; | |
1da177e4 | 557 | return -EFAULT; |
c654d60e | 558 | } |
1da177e4 LT |
559 | outb(c,i); |
560 | i++; | |
561 | tmp++; | |
562 | } | |
563 | *ppos = i; | |
564 | return tmp-buf; | |
565 | } | |
566 | #endif | |
567 | ||
568 | static ssize_t read_null(struct file * file, char __user * buf, | |
569 | size_t count, loff_t *ppos) | |
570 | { | |
571 | return 0; | |
572 | } | |
573 | ||
574 | static ssize_t write_null(struct file * file, const char __user * buf, | |
575 | size_t count, loff_t *ppos) | |
576 | { | |
577 | return count; | |
578 | } | |
579 | ||
1ebd32fc JA |
580 | static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, |
581 | struct splice_desc *sd) | |
582 | { | |
583 | return sd->len; | |
584 | } | |
585 | ||
586 | static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out, | |
587 | loff_t *ppos, size_t len, unsigned int flags) | |
588 | { | |
589 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); | |
590 | } | |
591 | ||
1da177e4 LT |
592 | #ifdef CONFIG_MMU |
593 | /* | |
594 | * For fun, we are using the MMU for this. | |
595 | */ | |
596 | static inline size_t read_zero_pagealigned(char __user * buf, size_t size) | |
597 | { | |
598 | struct mm_struct *mm; | |
599 | struct vm_area_struct * vma; | |
600 | unsigned long addr=(unsigned long)buf; | |
601 | ||
602 | mm = current->mm; | |
603 | /* Oops, this was forgotten before. -ben */ | |
604 | down_read(&mm->mmap_sem); | |
605 | ||
606 | /* For private mappings, just map in zero pages. */ | |
607 | for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) { | |
608 | unsigned long count; | |
609 | ||
610 | if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0) | |
611 | goto out_up; | |
6aab341e | 612 | if (vma->vm_flags & (VM_SHARED | VM_HUGETLB)) |
1da177e4 LT |
613 | break; |
614 | count = vma->vm_end - addr; | |
615 | if (count > size) | |
616 | count = size; | |
617 | ||
618 | zap_page_range(vma, addr, count, NULL); | |
619 | zeromap_page_range(vma, addr, count, PAGE_COPY); | |
620 | ||
621 | size -= count; | |
622 | buf += count; | |
623 | addr += count; | |
624 | if (size == 0) | |
625 | goto out_up; | |
626 | } | |
627 | ||
628 | up_read(&mm->mmap_sem); | |
629 | ||
630 | /* The shared case is hard. Let's do the conventional zeroing. */ | |
631 | do { | |
632 | unsigned long unwritten = clear_user(buf, PAGE_SIZE); | |
633 | if (unwritten) | |
634 | return size + unwritten - PAGE_SIZE; | |
635 | cond_resched(); | |
636 | buf += PAGE_SIZE; | |
637 | size -= PAGE_SIZE; | |
638 | } while (size); | |
639 | ||
640 | return size; | |
641 | out_up: | |
642 | up_read(&mm->mmap_sem); | |
643 | return size; | |
644 | } | |
645 | ||
646 | static ssize_t read_zero(struct file * file, char __user * buf, | |
647 | size_t count, loff_t *ppos) | |
648 | { | |
649 | unsigned long left, unwritten, written = 0; | |
650 | ||
651 | if (!count) | |
652 | return 0; | |
653 | ||
654 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
655 | return -EFAULT; | |
656 | ||
657 | left = count; | |
658 | ||
659 | /* do we want to be clever? Arbitrary cut-off */ | |
660 | if (count >= PAGE_SIZE*4) { | |
661 | unsigned long partial; | |
662 | ||
663 | /* How much left of the page? */ | |
664 | partial = (PAGE_SIZE-1) & -(unsigned long) buf; | |
665 | unwritten = clear_user(buf, partial); | |
666 | written = partial - unwritten; | |
667 | if (unwritten) | |
668 | goto out; | |
669 | left -= partial; | |
670 | buf += partial; | |
671 | unwritten = read_zero_pagealigned(buf, left & PAGE_MASK); | |
672 | written += (left & PAGE_MASK) - unwritten; | |
673 | if (unwritten) | |
674 | goto out; | |
675 | buf += left & PAGE_MASK; | |
676 | left &= ~PAGE_MASK; | |
677 | } | |
678 | unwritten = clear_user(buf, left); | |
679 | written += left - unwritten; | |
680 | out: | |
681 | return written ? written : -EFAULT; | |
682 | } | |
683 | ||
684 | static int mmap_zero(struct file * file, struct vm_area_struct * vma) | |
685 | { | |
686 | if (vma->vm_flags & VM_SHARED) | |
687 | return shmem_zero_setup(vma); | |
688 | if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot)) | |
689 | return -EAGAIN; | |
690 | return 0; | |
691 | } | |
692 | #else /* CONFIG_MMU */ | |
693 | static ssize_t read_zero(struct file * file, char * buf, | |
694 | size_t count, loff_t *ppos) | |
695 | { | |
696 | size_t todo = count; | |
697 | ||
698 | while (todo) { | |
699 | size_t chunk = todo; | |
700 | ||
701 | if (chunk > 4096) | |
702 | chunk = 4096; /* Just for latency reasons */ | |
703 | if (clear_user(buf, chunk)) | |
704 | return -EFAULT; | |
705 | buf += chunk; | |
706 | todo -= chunk; | |
707 | cond_resched(); | |
708 | } | |
709 | return count; | |
710 | } | |
711 | ||
712 | static int mmap_zero(struct file * file, struct vm_area_struct * vma) | |
713 | { | |
714 | return -ENOSYS; | |
715 | } | |
716 | #endif /* CONFIG_MMU */ | |
717 | ||
718 | static ssize_t write_full(struct file * file, const char __user * buf, | |
719 | size_t count, loff_t *ppos) | |
720 | { | |
721 | return -ENOSPC; | |
722 | } | |
723 | ||
724 | /* | |
725 | * Special lseek() function for /dev/null and /dev/zero. Most notably, you | |
726 | * can fopen() both devices with "a" now. This was previously impossible. | |
727 | * -- SRB. | |
728 | */ | |
729 | ||
730 | static loff_t null_lseek(struct file * file, loff_t offset, int orig) | |
731 | { | |
732 | return file->f_pos = 0; | |
733 | } | |
734 | ||
735 | /* | |
736 | * The memory devices use the full 32/64 bits of the offset, and so we cannot | |
737 | * check against negative addresses: they are ok. The return value is weird, | |
738 | * though, in that case (0). | |
739 | * | |
740 | * also note that seeking relative to the "end of file" isn't supported: | |
741 | * it has no meaning, so it returns -EINVAL. | |
742 | */ | |
743 | static loff_t memory_lseek(struct file * file, loff_t offset, int orig) | |
744 | { | |
745 | loff_t ret; | |
746 | ||
1b1dcc1b | 747 | mutex_lock(&file->f_dentry->d_inode->i_mutex); |
1da177e4 LT |
748 | switch (orig) { |
749 | case 0: | |
750 | file->f_pos = offset; | |
751 | ret = file->f_pos; | |
752 | force_successful_syscall_return(); | |
753 | break; | |
754 | case 1: | |
755 | file->f_pos += offset; | |
756 | ret = file->f_pos; | |
757 | force_successful_syscall_return(); | |
758 | break; | |
759 | default: | |
760 | ret = -EINVAL; | |
761 | } | |
1b1dcc1b | 762 | mutex_unlock(&file->f_dentry->d_inode->i_mutex); |
1da177e4 LT |
763 | return ret; |
764 | } | |
765 | ||
766 | static int open_port(struct inode * inode, struct file * filp) | |
767 | { | |
768 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; | |
769 | } | |
770 | ||
771 | #define zero_lseek null_lseek | |
772 | #define full_lseek null_lseek | |
773 | #define write_zero write_null | |
774 | #define read_full read_zero | |
775 | #define open_mem open_port | |
776 | #define open_kmem open_mem | |
50b1fdbd | 777 | #define open_oldmem open_mem |
1da177e4 | 778 | |
62322d25 | 779 | static const struct file_operations mem_fops = { |
1da177e4 LT |
780 | .llseek = memory_lseek, |
781 | .read = read_mem, | |
782 | .write = write_mem, | |
783 | .mmap = mmap_mem, | |
784 | .open = open_mem, | |
785 | }; | |
786 | ||
62322d25 | 787 | static const struct file_operations kmem_fops = { |
1da177e4 LT |
788 | .llseek = memory_lseek, |
789 | .read = read_kmem, | |
790 | .write = write_kmem, | |
791 | .mmap = mmap_kmem, | |
792 | .open = open_kmem, | |
793 | }; | |
794 | ||
62322d25 | 795 | static const struct file_operations null_fops = { |
1da177e4 LT |
796 | .llseek = null_lseek, |
797 | .read = read_null, | |
798 | .write = write_null, | |
1ebd32fc | 799 | .splice_write = splice_write_null, |
1da177e4 LT |
800 | }; |
801 | ||
ee2cdece | 802 | #if defined(CONFIG_ISA) || !defined(__mc68000__) |
62322d25 | 803 | static const struct file_operations port_fops = { |
1da177e4 LT |
804 | .llseek = memory_lseek, |
805 | .read = read_port, | |
806 | .write = write_port, | |
807 | .open = open_port, | |
808 | }; | |
809 | #endif | |
810 | ||
62322d25 | 811 | static const struct file_operations zero_fops = { |
1da177e4 LT |
812 | .llseek = zero_lseek, |
813 | .read = read_zero, | |
814 | .write = write_zero, | |
815 | .mmap = mmap_zero, | |
816 | }; | |
817 | ||
818 | static struct backing_dev_info zero_bdi = { | |
819 | .capabilities = BDI_CAP_MAP_COPY, | |
820 | }; | |
821 | ||
62322d25 | 822 | static const struct file_operations full_fops = { |
1da177e4 LT |
823 | .llseek = full_lseek, |
824 | .read = read_full, | |
825 | .write = write_full, | |
826 | }; | |
827 | ||
50b1fdbd | 828 | #ifdef CONFIG_CRASH_DUMP |
62322d25 | 829 | static const struct file_operations oldmem_fops = { |
50b1fdbd VG |
830 | .read = read_oldmem, |
831 | .open = open_oldmem, | |
832 | }; | |
833 | #endif | |
834 | ||
1da177e4 LT |
835 | static ssize_t kmsg_write(struct file * file, const char __user * buf, |
836 | size_t count, loff_t *ppos) | |
837 | { | |
838 | char *tmp; | |
cd140a5c | 839 | ssize_t ret; |
1da177e4 LT |
840 | |
841 | tmp = kmalloc(count + 1, GFP_KERNEL); | |
842 | if (tmp == NULL) | |
843 | return -ENOMEM; | |
844 | ret = -EFAULT; | |
845 | if (!copy_from_user(tmp, buf, count)) { | |
846 | tmp[count] = 0; | |
847 | ret = printk("%s", tmp); | |
cd140a5c GC |
848 | if (ret > count) |
849 | /* printk can add a prefix */ | |
850 | ret = count; | |
1da177e4 LT |
851 | } |
852 | kfree(tmp); | |
853 | return ret; | |
854 | } | |
855 | ||
62322d25 | 856 | static const struct file_operations kmsg_fops = { |
1da177e4 LT |
857 | .write = kmsg_write, |
858 | }; | |
859 | ||
860 | static int memory_open(struct inode * inode, struct file * filp) | |
861 | { | |
862 | switch (iminor(inode)) { | |
863 | case 1: | |
864 | filp->f_op = &mem_fops; | |
865 | break; | |
866 | case 2: | |
867 | filp->f_op = &kmem_fops; | |
868 | break; | |
869 | case 3: | |
870 | filp->f_op = &null_fops; | |
871 | break; | |
ee2cdece | 872 | #if defined(CONFIG_ISA) || !defined(__mc68000__) |
1da177e4 LT |
873 | case 4: |
874 | filp->f_op = &port_fops; | |
875 | break; | |
876 | #endif | |
877 | case 5: | |
878 | filp->f_mapping->backing_dev_info = &zero_bdi; | |
879 | filp->f_op = &zero_fops; | |
880 | break; | |
881 | case 7: | |
882 | filp->f_op = &full_fops; | |
883 | break; | |
884 | case 8: | |
885 | filp->f_op = &random_fops; | |
886 | break; | |
887 | case 9: | |
888 | filp->f_op = &urandom_fops; | |
889 | break; | |
890 | case 11: | |
891 | filp->f_op = &kmsg_fops; | |
892 | break; | |
50b1fdbd VG |
893 | #ifdef CONFIG_CRASH_DUMP |
894 | case 12: | |
895 | filp->f_op = &oldmem_fops; | |
896 | break; | |
897 | #endif | |
1da177e4 LT |
898 | default: |
899 | return -ENXIO; | |
900 | } | |
901 | if (filp->f_op && filp->f_op->open) | |
902 | return filp->f_op->open(inode,filp); | |
903 | return 0; | |
904 | } | |
905 | ||
62322d25 | 906 | static const struct file_operations memory_fops = { |
1da177e4 LT |
907 | .open = memory_open, /* just a selector for the real open */ |
908 | }; | |
909 | ||
910 | static const struct { | |
911 | unsigned int minor; | |
912 | char *name; | |
913 | umode_t mode; | |
99ac48f5 | 914 | const struct file_operations *fops; |
1da177e4 LT |
915 | } devlist[] = { /* list of minor devices */ |
916 | {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops}, | |
917 | {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops}, | |
918 | {3, "null", S_IRUGO | S_IWUGO, &null_fops}, | |
ee2cdece | 919 | #if defined(CONFIG_ISA) || !defined(__mc68000__) |
1da177e4 LT |
920 | {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops}, |
921 | #endif | |
922 | {5, "zero", S_IRUGO | S_IWUGO, &zero_fops}, | |
923 | {7, "full", S_IRUGO | S_IWUGO, &full_fops}, | |
924 | {8, "random", S_IRUGO | S_IWUSR, &random_fops}, | |
925 | {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops}, | |
926 | {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops}, | |
50b1fdbd VG |
927 | #ifdef CONFIG_CRASH_DUMP |
928 | {12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops}, | |
929 | #endif | |
1da177e4 LT |
930 | }; |
931 | ||
ca8eca68 | 932 | static struct class *mem_class; |
1da177e4 LT |
933 | |
934 | static int __init chr_dev_init(void) | |
935 | { | |
936 | int i; | |
937 | ||
938 | if (register_chrdev(MEM_MAJOR,"mem",&memory_fops)) | |
939 | printk("unable to get major %d for memory devs\n", MEM_MAJOR); | |
940 | ||
ca8eca68 | 941 | mem_class = class_create(THIS_MODULE, "mem"); |
7c69ef79 | 942 | for (i = 0; i < ARRAY_SIZE(devlist); i++) |
53f46542 GKH |
943 | class_device_create(mem_class, NULL, |
944 | MKDEV(MEM_MAJOR, devlist[i].minor), | |
1da177e4 | 945 | NULL, devlist[i].name); |
1da177e4 LT |
946 | |
947 | return 0; | |
948 | } | |
949 | ||
950 | fs_initcall(chr_dev_init); |