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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> | |
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> |
1f439647 | 29 | #include <linux/smp_lock.h> |
1da177e4 LT |
30 | |
31 | #include <asm/uaccess.h> | |
32 | #include <asm/io.h> | |
33 | ||
34 | #ifdef CONFIG_IA64 | |
35 | # include <linux/efi.h> | |
36 | #endif | |
37 | ||
1da177e4 LT |
38 | /* |
39 | * Architectures vary in how they handle caching for addresses | |
40 | * outside of main memory. | |
41 | * | |
42 | */ | |
43 | static inline int uncached_access(struct file *file, unsigned long addr) | |
44 | { | |
f0970c13 | 45 | #if defined(CONFIG_IA64) |
1da177e4 LT |
46 | /* |
47 | * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases. | |
48 | */ | |
49 | return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); | |
24e9d0b9 RB |
50 | #elif defined(CONFIG_MIPS) |
51 | { | |
52 | extern int __uncached_access(struct file *file, | |
53 | unsigned long addr); | |
54 | ||
55 | return __uncached_access(file, addr); | |
56 | } | |
1da177e4 LT |
57 | #else |
58 | /* | |
59 | * Accessing memory above the top the kernel knows about or through a file pointer | |
60 | * that was marked O_SYNC will be done non-cached. | |
61 | */ | |
62 | if (file->f_flags & O_SYNC) | |
63 | return 1; | |
64 | return addr >= __pa(high_memory); | |
65 | #endif | |
66 | } | |
67 | ||
68 | #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE | |
136939a2 | 69 | static inline int valid_phys_addr_range(unsigned long addr, size_t count) |
1da177e4 | 70 | { |
136939a2 | 71 | if (addr + count > __pa(high_memory)) |
1da177e4 LT |
72 | return 0; |
73 | ||
1da177e4 LT |
74 | return 1; |
75 | } | |
80851ef2 | 76 | |
06c67bef | 77 | static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) |
80851ef2 BH |
78 | { |
79 | return 1; | |
80 | } | |
1da177e4 LT |
81 | #endif |
82 | ||
d092633b | 83 | #ifdef CONFIG_STRICT_DEVMEM |
e2beb3ea | 84 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 | 85 | { |
e2beb3ea VP |
86 | u64 from = ((u64)pfn) << PAGE_SHIFT; |
87 | u64 to = from + size; | |
88 | u64 cursor = from; | |
89 | ||
90 | while (cursor < to) { | |
91 | if (!devmem_is_allowed(pfn)) { | |
92 | printk(KERN_INFO | |
93 | "Program %s tried to access /dev/mem between %Lx->%Lx.\n", | |
ae531c26 AV |
94 | current->comm, from, to); |
95 | return 0; | |
96 | } | |
e2beb3ea VP |
97 | cursor += PAGE_SIZE; |
98 | pfn++; | |
ae531c26 AV |
99 | } |
100 | return 1; | |
101 | } | |
102 | #else | |
e2beb3ea | 103 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 AV |
104 | { |
105 | return 1; | |
106 | } | |
107 | #endif | |
108 | ||
e045fb2a | 109 | void __attribute__((weak)) unxlate_dev_mem_ptr(unsigned long phys, void *addr) |
110 | { | |
111 | } | |
112 | ||
1da177e4 LT |
113 | /* |
114 | * This funcion reads the *physical* memory. The f_pos points directly to the | |
115 | * memory location. | |
116 | */ | |
117 | static ssize_t read_mem(struct file * file, char __user * buf, | |
118 | size_t count, loff_t *ppos) | |
119 | { | |
120 | unsigned long p = *ppos; | |
121 | ssize_t read, sz; | |
122 | char *ptr; | |
123 | ||
136939a2 | 124 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
125 | return -EFAULT; |
126 | read = 0; | |
127 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
128 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
129 | if (p < PAGE_SIZE) { | |
130 | sz = PAGE_SIZE - p; | |
131 | if (sz > count) | |
132 | sz = count; | |
133 | if (sz > 0) { | |
134 | if (clear_user(buf, sz)) | |
135 | return -EFAULT; | |
136 | buf += sz; | |
137 | p += sz; | |
138 | count -= sz; | |
139 | read += sz; | |
140 | } | |
141 | } | |
142 | #endif | |
143 | ||
144 | while (count > 0) { | |
145 | /* | |
146 | * Handle first page in case it's not aligned | |
147 | */ | |
148 | if (-p & (PAGE_SIZE - 1)) | |
149 | sz = -p & (PAGE_SIZE - 1); | |
150 | else | |
151 | sz = PAGE_SIZE; | |
152 | ||
153 | sz = min_t(unsigned long, sz, count); | |
154 | ||
e045fb2a | 155 | if (!range_is_allowed(p >> PAGE_SHIFT, count)) |
156 | return -EPERM; | |
157 | ||
1da177e4 LT |
158 | /* |
159 | * On ia64 if a page has been mapped somewhere as | |
160 | * uncached, then it must also be accessed uncached | |
161 | * by the kernel or data corruption may occur | |
162 | */ | |
163 | ptr = xlate_dev_mem_ptr(p); | |
e045fb2a | 164 | if (!ptr) |
165 | return -EFAULT; | |
1da177e4 | 166 | |
e045fb2a | 167 | if (copy_to_user(buf, ptr, sz)) { |
168 | unxlate_dev_mem_ptr(p, ptr); | |
1da177e4 | 169 | return -EFAULT; |
e045fb2a | 170 | } |
171 | ||
172 | unxlate_dev_mem_ptr(p, ptr); | |
173 | ||
1da177e4 LT |
174 | buf += sz; |
175 | p += sz; | |
176 | count -= sz; | |
177 | read += sz; | |
178 | } | |
179 | ||
180 | *ppos += read; | |
181 | return read; | |
182 | } | |
183 | ||
184 | static ssize_t write_mem(struct file * file, const char __user * buf, | |
185 | size_t count, loff_t *ppos) | |
186 | { | |
187 | unsigned long p = *ppos; | |
188 | ssize_t written, sz; | |
189 | unsigned long copied; | |
190 | void *ptr; | |
191 | ||
136939a2 | 192 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
193 | return -EFAULT; |
194 | ||
195 | written = 0; | |
196 | ||
197 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
198 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
199 | if (p < PAGE_SIZE) { | |
200 | unsigned long sz = PAGE_SIZE - p; | |
201 | if (sz > count) | |
202 | sz = count; | |
203 | /* Hmm. Do something? */ | |
204 | buf += sz; | |
205 | p += sz; | |
206 | count -= sz; | |
207 | written += sz; | |
208 | } | |
209 | #endif | |
210 | ||
211 | while (count > 0) { | |
212 | /* | |
213 | * Handle first page in case it's not aligned | |
214 | */ | |
215 | if (-p & (PAGE_SIZE - 1)) | |
216 | sz = -p & (PAGE_SIZE - 1); | |
217 | else | |
218 | sz = PAGE_SIZE; | |
219 | ||
220 | sz = min_t(unsigned long, sz, count); | |
221 | ||
e045fb2a | 222 | if (!range_is_allowed(p >> PAGE_SHIFT, sz)) |
223 | return -EPERM; | |
224 | ||
1da177e4 LT |
225 | /* |
226 | * On ia64 if a page has been mapped somewhere as | |
227 | * uncached, then it must also be accessed uncached | |
228 | * by the kernel or data corruption may occur | |
229 | */ | |
230 | ptr = xlate_dev_mem_ptr(p); | |
e045fb2a | 231 | if (!ptr) { |
232 | if (written) | |
233 | break; | |
234 | return -EFAULT; | |
235 | } | |
1da177e4 LT |
236 | |
237 | copied = copy_from_user(ptr, buf, sz); | |
238 | if (copied) { | |
c654d60e | 239 | written += sz - copied; |
e045fb2a | 240 | unxlate_dev_mem_ptr(p, ptr); |
c654d60e JB |
241 | if (written) |
242 | break; | |
1da177e4 LT |
243 | return -EFAULT; |
244 | } | |
e045fb2a | 245 | |
246 | unxlate_dev_mem_ptr(p, ptr); | |
247 | ||
1da177e4 LT |
248 | buf += sz; |
249 | p += sz; | |
250 | count -= sz; | |
251 | written += sz; | |
252 | } | |
253 | ||
254 | *ppos += written; | |
255 | return written; | |
256 | } | |
257 | ||
f0970c13 | 258 | int __attribute__((weak)) phys_mem_access_prot_allowed(struct file *file, |
259 | unsigned long pfn, unsigned long size, pgprot_t *vma_prot) | |
260 | { | |
261 | return 1; | |
262 | } | |
263 | ||
44ac8413 BH |
264 | #ifndef __HAVE_PHYS_MEM_ACCESS_PROT |
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 | |
269 | unsigned long offset = pfn << PAGE_SHIFT; | |
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 | ||
e7f260a2 | 304 | void __attribute__((weak)) |
305 | map_devmem(unsigned long pfn, unsigned long len, pgprot_t prot) | |
306 | { | |
307 | /* nothing. architectures can override. */ | |
308 | } | |
309 | ||
310 | void __attribute__((weak)) | |
311 | unmap_devmem(unsigned long pfn, unsigned long len, pgprot_t prot) | |
312 | { | |
313 | /* nothing. architectures can override. */ | |
314 | } | |
315 | ||
316 | static void mmap_mem_open(struct vm_area_struct *vma) | |
317 | { | |
318 | map_devmem(vma->vm_pgoff, vma->vm_end - vma->vm_start, | |
319 | vma->vm_page_prot); | |
320 | } | |
321 | ||
322 | static void mmap_mem_close(struct vm_area_struct *vma) | |
323 | { | |
324 | unmap_devmem(vma->vm_pgoff, vma->vm_end - vma->vm_start, | |
325 | vma->vm_page_prot); | |
326 | } | |
327 | ||
328 | static struct vm_operations_struct mmap_mem_ops = { | |
329 | .open = mmap_mem_open, | |
7ae8ed50 RR |
330 | .close = mmap_mem_close, |
331 | #ifdef CONFIG_HAVE_IOREMAP_PROT | |
332 | .access = generic_access_phys | |
333 | #endif | |
e7f260a2 | 334 | }; |
335 | ||
1da177e4 LT |
336 | static int mmap_mem(struct file * file, struct vm_area_struct * vma) |
337 | { | |
80851ef2 BH |
338 | size_t size = vma->vm_end - vma->vm_start; |
339 | ||
06c67bef | 340 | if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) |
80851ef2 BH |
341 | return -EINVAL; |
342 | ||
5da6185b DH |
343 | if (!private_mapping_ok(vma)) |
344 | return -ENOSYS; | |
345 | ||
e2beb3ea VP |
346 | if (!range_is_allowed(vma->vm_pgoff, size)) |
347 | return -EPERM; | |
348 | ||
f0970c13 | 349 | if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, |
350 | &vma->vm_page_prot)) | |
351 | return -EINVAL; | |
352 | ||
8b150478 | 353 | vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, |
80851ef2 | 354 | size, |
1da177e4 | 355 | vma->vm_page_prot); |
1da177e4 | 356 | |
e7f260a2 | 357 | vma->vm_ops = &mmap_mem_ops; |
358 | ||
1da177e4 LT |
359 | /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ |
360 | if (remap_pfn_range(vma, | |
361 | vma->vm_start, | |
362 | vma->vm_pgoff, | |
80851ef2 | 363 | size, |
e7f260a2 | 364 | vma->vm_page_prot)) { |
365 | unmap_devmem(vma->vm_pgoff, size, vma->vm_page_prot); | |
1da177e4 | 366 | return -EAGAIN; |
e7f260a2 | 367 | } |
1da177e4 LT |
368 | return 0; |
369 | } | |
370 | ||
b781ecb6 | 371 | #ifdef CONFIG_DEVKMEM |
1da177e4 LT |
372 | static int mmap_kmem(struct file * file, struct vm_area_struct * vma) |
373 | { | |
4bb82551 LT |
374 | unsigned long pfn; |
375 | ||
6d3154cc LT |
376 | /* Turn a kernel-virtual address into a physical page frame */ |
377 | pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; | |
4bb82551 | 378 | |
1da177e4 LT |
379 | /* |
380 | * RED-PEN: on some architectures there is more mapped memory | |
381 | * than available in mem_map which pfn_valid checks | |
382 | * for. Perhaps should add a new macro here. | |
383 | * | |
384 | * RED-PEN: vmalloc is not supported right now. | |
385 | */ | |
4bb82551 | 386 | if (!pfn_valid(pfn)) |
1da177e4 | 387 | return -EIO; |
4bb82551 LT |
388 | |
389 | vma->vm_pgoff = pfn; | |
1da177e4 LT |
390 | return mmap_mem(file, vma); |
391 | } | |
b781ecb6 | 392 | #endif |
1da177e4 | 393 | |
50b1fdbd VG |
394 | #ifdef CONFIG_CRASH_DUMP |
395 | /* | |
396 | * Read memory corresponding to the old kernel. | |
50b1fdbd | 397 | */ |
315c215c | 398 | static ssize_t read_oldmem(struct file *file, char __user *buf, |
50b1fdbd VG |
399 | size_t count, loff_t *ppos) |
400 | { | |
315c215c VG |
401 | unsigned long pfn, offset; |
402 | size_t read = 0, csize; | |
403 | int rc = 0; | |
50b1fdbd | 404 | |
72414d3f | 405 | while (count) { |
50b1fdbd | 406 | pfn = *ppos / PAGE_SIZE; |
315c215c VG |
407 | if (pfn > saved_max_pfn) |
408 | return read; | |
50b1fdbd | 409 | |
315c215c VG |
410 | offset = (unsigned long)(*ppos % PAGE_SIZE); |
411 | if (count > PAGE_SIZE - offset) | |
412 | csize = PAGE_SIZE - offset; | |
413 | else | |
414 | csize = count; | |
50b1fdbd | 415 | |
315c215c VG |
416 | rc = copy_oldmem_page(pfn, buf, csize, offset, 1); |
417 | if (rc < 0) | |
418 | return rc; | |
50b1fdbd VG |
419 | buf += csize; |
420 | *ppos += csize; | |
421 | read += csize; | |
422 | count -= csize; | |
423 | } | |
50b1fdbd VG |
424 | return read; |
425 | } | |
426 | #endif | |
1da177e4 | 427 | |
b781ecb6 | 428 | #ifdef CONFIG_DEVKMEM |
1da177e4 LT |
429 | /* |
430 | * This function reads the *virtual* memory as seen by the kernel. | |
431 | */ | |
432 | static ssize_t read_kmem(struct file *file, char __user *buf, | |
433 | size_t count, loff_t *ppos) | |
434 | { | |
435 | unsigned long p = *ppos; | |
436 | ssize_t low_count, read, sz; | |
437 | char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ | |
438 | ||
439 | read = 0; | |
440 | if (p < (unsigned long) high_memory) { | |
441 | low_count = count; | |
442 | if (count > (unsigned long) high_memory - p) | |
443 | low_count = (unsigned long) high_memory - p; | |
444 | ||
445 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
446 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
447 | if (p < PAGE_SIZE && low_count > 0) { | |
448 | size_t tmp = PAGE_SIZE - p; | |
449 | if (tmp > low_count) tmp = low_count; | |
450 | if (clear_user(buf, tmp)) | |
451 | return -EFAULT; | |
452 | buf += tmp; | |
453 | p += tmp; | |
454 | read += tmp; | |
455 | low_count -= tmp; | |
456 | count -= tmp; | |
457 | } | |
458 | #endif | |
459 | while (low_count > 0) { | |
460 | /* | |
461 | * Handle first page in case it's not aligned | |
462 | */ | |
463 | if (-p & (PAGE_SIZE - 1)) | |
464 | sz = -p & (PAGE_SIZE - 1); | |
465 | else | |
466 | sz = PAGE_SIZE; | |
467 | ||
468 | sz = min_t(unsigned long, sz, low_count); | |
469 | ||
470 | /* | |
471 | * On ia64 if a page has been mapped somewhere as | |
472 | * uncached, then it must also be accessed uncached | |
473 | * by the kernel or data corruption may occur | |
474 | */ | |
475 | kbuf = xlate_dev_kmem_ptr((char *)p); | |
476 | ||
477 | if (copy_to_user(buf, kbuf, sz)) | |
478 | return -EFAULT; | |
479 | buf += sz; | |
480 | p += sz; | |
481 | read += sz; | |
482 | low_count -= sz; | |
483 | count -= sz; | |
484 | } | |
485 | } | |
486 | ||
487 | if (count > 0) { | |
488 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
489 | if (!kbuf) | |
490 | return -ENOMEM; | |
491 | while (count > 0) { | |
492 | int len = count; | |
493 | ||
494 | if (len > PAGE_SIZE) | |
495 | len = PAGE_SIZE; | |
496 | len = vread(kbuf, (char *)p, len); | |
497 | if (!len) | |
498 | break; | |
499 | if (copy_to_user(buf, kbuf, len)) { | |
500 | free_page((unsigned long)kbuf); | |
501 | return -EFAULT; | |
502 | } | |
503 | count -= len; | |
504 | buf += len; | |
505 | read += len; | |
506 | p += len; | |
507 | } | |
508 | free_page((unsigned long)kbuf); | |
509 | } | |
510 | *ppos = p; | |
511 | return read; | |
512 | } | |
513 | ||
514 | ||
515 | static inline ssize_t | |
516 | do_write_kmem(void *p, unsigned long realp, const char __user * buf, | |
517 | size_t count, loff_t *ppos) | |
518 | { | |
519 | ssize_t written, sz; | |
520 | unsigned long copied; | |
521 | ||
522 | written = 0; | |
523 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
524 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
525 | if (realp < PAGE_SIZE) { | |
526 | unsigned long sz = PAGE_SIZE - realp; | |
527 | if (sz > count) | |
528 | sz = count; | |
529 | /* Hmm. Do something? */ | |
530 | buf += sz; | |
531 | p += sz; | |
532 | realp += sz; | |
533 | count -= sz; | |
534 | written += sz; | |
535 | } | |
536 | #endif | |
537 | ||
538 | while (count > 0) { | |
539 | char *ptr; | |
540 | /* | |
541 | * Handle first page in case it's not aligned | |
542 | */ | |
543 | if (-realp & (PAGE_SIZE - 1)) | |
544 | sz = -realp & (PAGE_SIZE - 1); | |
545 | else | |
546 | sz = PAGE_SIZE; | |
547 | ||
548 | sz = min_t(unsigned long, sz, count); | |
549 | ||
550 | /* | |
551 | * On ia64 if a page has been mapped somewhere as | |
552 | * uncached, then it must also be accessed uncached | |
553 | * by the kernel or data corruption may occur | |
554 | */ | |
555 | ptr = xlate_dev_kmem_ptr(p); | |
556 | ||
557 | copied = copy_from_user(ptr, buf, sz); | |
558 | if (copied) { | |
c654d60e JB |
559 | written += sz - copied; |
560 | if (written) | |
561 | break; | |
1da177e4 LT |
562 | return -EFAULT; |
563 | } | |
564 | buf += sz; | |
565 | p += sz; | |
566 | realp += sz; | |
567 | count -= sz; | |
568 | written += sz; | |
569 | } | |
570 | ||
571 | *ppos += written; | |
572 | return written; | |
573 | } | |
574 | ||
575 | ||
576 | /* | |
577 | * This function writes to the *virtual* memory as seen by the kernel. | |
578 | */ | |
579 | static ssize_t write_kmem(struct file * file, const char __user * buf, | |
580 | size_t count, loff_t *ppos) | |
581 | { | |
582 | unsigned long p = *ppos; | |
583 | ssize_t wrote = 0; | |
584 | ssize_t virtr = 0; | |
585 | ssize_t written; | |
586 | char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ | |
587 | ||
588 | if (p < (unsigned long) high_memory) { | |
589 | ||
590 | wrote = count; | |
591 | if (count > (unsigned long) high_memory - p) | |
592 | wrote = (unsigned long) high_memory - p; | |
593 | ||
594 | written = do_write_kmem((void*)p, p, buf, wrote, ppos); | |
595 | if (written != wrote) | |
596 | return written; | |
597 | wrote = written; | |
598 | p += wrote; | |
599 | buf += wrote; | |
600 | count -= wrote; | |
601 | } | |
602 | ||
603 | if (count > 0) { | |
604 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
605 | if (!kbuf) | |
606 | return wrote ? wrote : -ENOMEM; | |
607 | while (count > 0) { | |
608 | int len = count; | |
609 | ||
610 | if (len > PAGE_SIZE) | |
611 | len = PAGE_SIZE; | |
612 | if (len) { | |
613 | written = copy_from_user(kbuf, buf, len); | |
614 | if (written) { | |
c654d60e JB |
615 | if (wrote + virtr) |
616 | break; | |
1da177e4 | 617 | free_page((unsigned long)kbuf); |
c654d60e | 618 | return -EFAULT; |
1da177e4 LT |
619 | } |
620 | } | |
621 | len = vwrite(kbuf, (char *)p, len); | |
622 | count -= len; | |
623 | buf += len; | |
624 | virtr += len; | |
625 | p += len; | |
626 | } | |
627 | free_page((unsigned long)kbuf); | |
628 | } | |
629 | ||
630 | *ppos = p; | |
631 | return virtr + wrote; | |
632 | } | |
b781ecb6 | 633 | #endif |
1da177e4 | 634 | |
4f911d64 | 635 | #ifdef CONFIG_DEVPORT |
1da177e4 LT |
636 | static ssize_t read_port(struct file * file, char __user * buf, |
637 | size_t count, loff_t *ppos) | |
638 | { | |
639 | unsigned long i = *ppos; | |
640 | char __user *tmp = buf; | |
641 | ||
642 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
643 | return -EFAULT; | |
644 | while (count-- > 0 && i < 65536) { | |
645 | if (__put_user(inb(i),tmp) < 0) | |
646 | return -EFAULT; | |
647 | i++; | |
648 | tmp++; | |
649 | } | |
650 | *ppos = i; | |
651 | return tmp-buf; | |
652 | } | |
653 | ||
654 | static ssize_t write_port(struct file * file, const char __user * buf, | |
655 | size_t count, loff_t *ppos) | |
656 | { | |
657 | unsigned long i = *ppos; | |
658 | const char __user * tmp = buf; | |
659 | ||
660 | if (!access_ok(VERIFY_READ,buf,count)) | |
661 | return -EFAULT; | |
662 | while (count-- > 0 && i < 65536) { | |
663 | char c; | |
c654d60e JB |
664 | if (__get_user(c, tmp)) { |
665 | if (tmp > buf) | |
666 | break; | |
1da177e4 | 667 | return -EFAULT; |
c654d60e | 668 | } |
1da177e4 LT |
669 | outb(c,i); |
670 | i++; | |
671 | tmp++; | |
672 | } | |
673 | *ppos = i; | |
674 | return tmp-buf; | |
675 | } | |
676 | #endif | |
677 | ||
678 | static ssize_t read_null(struct file * file, char __user * buf, | |
679 | size_t count, loff_t *ppos) | |
680 | { | |
681 | return 0; | |
682 | } | |
683 | ||
684 | static ssize_t write_null(struct file * file, const char __user * buf, | |
685 | size_t count, loff_t *ppos) | |
686 | { | |
687 | return count; | |
688 | } | |
689 | ||
1ebd32fc JA |
690 | static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, |
691 | struct splice_desc *sd) | |
692 | { | |
693 | return sd->len; | |
694 | } | |
695 | ||
696 | static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out, | |
697 | loff_t *ppos, size_t len, unsigned int flags) | |
698 | { | |
699 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); | |
700 | } | |
701 | ||
1da177e4 LT |
702 | static ssize_t read_zero(struct file * file, char __user * buf, |
703 | size_t count, loff_t *ppos) | |
704 | { | |
557ed1fa | 705 | size_t written; |
1da177e4 LT |
706 | |
707 | if (!count) | |
708 | return 0; | |
709 | ||
710 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
711 | return -EFAULT; | |
712 | ||
557ed1fa NP |
713 | written = 0; |
714 | while (count) { | |
715 | unsigned long unwritten; | |
716 | size_t chunk = count; | |
1da177e4 | 717 | |
557ed1fa NP |
718 | if (chunk > PAGE_SIZE) |
719 | chunk = PAGE_SIZE; /* Just for latency reasons */ | |
720 | unwritten = clear_user(buf, chunk); | |
721 | written += chunk - unwritten; | |
1da177e4 | 722 | if (unwritten) |
557ed1fa | 723 | break; |
1da177e4 | 724 | buf += chunk; |
557ed1fa | 725 | count -= chunk; |
1da177e4 LT |
726 | cond_resched(); |
727 | } | |
557ed1fa | 728 | return written ? written : -EFAULT; |
1da177e4 LT |
729 | } |
730 | ||
731 | static int mmap_zero(struct file * file, struct vm_area_struct * vma) | |
732 | { | |
557ed1fa | 733 | #ifndef CONFIG_MMU |
1da177e4 | 734 | return -ENOSYS; |
557ed1fa NP |
735 | #endif |
736 | if (vma->vm_flags & VM_SHARED) | |
737 | return shmem_zero_setup(vma); | |
738 | return 0; | |
1da177e4 | 739 | } |
1da177e4 LT |
740 | |
741 | static ssize_t write_full(struct file * file, const char __user * buf, | |
742 | size_t count, loff_t *ppos) | |
743 | { | |
744 | return -ENOSPC; | |
745 | } | |
746 | ||
747 | /* | |
748 | * Special lseek() function for /dev/null and /dev/zero. Most notably, you | |
749 | * can fopen() both devices with "a" now. This was previously impossible. | |
750 | * -- SRB. | |
751 | */ | |
752 | ||
753 | static loff_t null_lseek(struct file * file, loff_t offset, int orig) | |
754 | { | |
755 | return file->f_pos = 0; | |
756 | } | |
757 | ||
758 | /* | |
759 | * The memory devices use the full 32/64 bits of the offset, and so we cannot | |
760 | * check against negative addresses: they are ok. The return value is weird, | |
761 | * though, in that case (0). | |
762 | * | |
763 | * also note that seeking relative to the "end of file" isn't supported: | |
764 | * it has no meaning, so it returns -EINVAL. | |
765 | */ | |
766 | static loff_t memory_lseek(struct file * file, loff_t offset, int orig) | |
767 | { | |
768 | loff_t ret; | |
769 | ||
a7113a96 | 770 | mutex_lock(&file->f_path.dentry->d_inode->i_mutex); |
1da177e4 LT |
771 | switch (orig) { |
772 | case 0: | |
773 | file->f_pos = offset; | |
774 | ret = file->f_pos; | |
775 | force_successful_syscall_return(); | |
776 | break; | |
777 | case 1: | |
778 | file->f_pos += offset; | |
779 | ret = file->f_pos; | |
780 | force_successful_syscall_return(); | |
781 | break; | |
782 | default: | |
783 | ret = -EINVAL; | |
784 | } | |
a7113a96 | 785 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
1da177e4 LT |
786 | return ret; |
787 | } | |
788 | ||
789 | static int open_port(struct inode * inode, struct file * filp) | |
790 | { | |
791 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; | |
792 | } | |
793 | ||
794 | #define zero_lseek null_lseek | |
795 | #define full_lseek null_lseek | |
796 | #define write_zero write_null | |
797 | #define read_full read_zero | |
798 | #define open_mem open_port | |
799 | #define open_kmem open_mem | |
50b1fdbd | 800 | #define open_oldmem open_mem |
1da177e4 | 801 | |
62322d25 | 802 | static const struct file_operations mem_fops = { |
1da177e4 LT |
803 | .llseek = memory_lseek, |
804 | .read = read_mem, | |
805 | .write = write_mem, | |
806 | .mmap = mmap_mem, | |
807 | .open = open_mem, | |
5da6185b | 808 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 LT |
809 | }; |
810 | ||
b781ecb6 | 811 | #ifdef CONFIG_DEVKMEM |
62322d25 | 812 | static const struct file_operations kmem_fops = { |
1da177e4 LT |
813 | .llseek = memory_lseek, |
814 | .read = read_kmem, | |
815 | .write = write_kmem, | |
816 | .mmap = mmap_kmem, | |
817 | .open = open_kmem, | |
5da6185b | 818 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 | 819 | }; |
b781ecb6 | 820 | #endif |
1da177e4 | 821 | |
62322d25 | 822 | static const struct file_operations null_fops = { |
1da177e4 LT |
823 | .llseek = null_lseek, |
824 | .read = read_null, | |
825 | .write = write_null, | |
1ebd32fc | 826 | .splice_write = splice_write_null, |
1da177e4 LT |
827 | }; |
828 | ||
4f911d64 | 829 | #ifdef CONFIG_DEVPORT |
62322d25 | 830 | static const struct file_operations port_fops = { |
1da177e4 LT |
831 | .llseek = memory_lseek, |
832 | .read = read_port, | |
833 | .write = write_port, | |
834 | .open = open_port, | |
835 | }; | |
836 | #endif | |
837 | ||
62322d25 | 838 | static const struct file_operations zero_fops = { |
1da177e4 LT |
839 | .llseek = zero_lseek, |
840 | .read = read_zero, | |
841 | .write = write_zero, | |
842 | .mmap = mmap_zero, | |
843 | }; | |
844 | ||
5da6185b DH |
845 | /* |
846 | * capabilities for /dev/zero | |
847 | * - permits private mappings, "copies" are taken of the source of zeros | |
848 | */ | |
1da177e4 LT |
849 | static struct backing_dev_info zero_bdi = { |
850 | .capabilities = BDI_CAP_MAP_COPY, | |
851 | }; | |
852 | ||
62322d25 | 853 | static const struct file_operations full_fops = { |
1da177e4 LT |
854 | .llseek = full_lseek, |
855 | .read = read_full, | |
856 | .write = write_full, | |
857 | }; | |
858 | ||
50b1fdbd | 859 | #ifdef CONFIG_CRASH_DUMP |
62322d25 | 860 | static const struct file_operations oldmem_fops = { |
50b1fdbd VG |
861 | .read = read_oldmem, |
862 | .open = open_oldmem, | |
863 | }; | |
864 | #endif | |
865 | ||
1da177e4 LT |
866 | static ssize_t kmsg_write(struct file * file, const char __user * buf, |
867 | size_t count, loff_t *ppos) | |
868 | { | |
869 | char *tmp; | |
cd140a5c | 870 | ssize_t ret; |
1da177e4 LT |
871 | |
872 | tmp = kmalloc(count + 1, GFP_KERNEL); | |
873 | if (tmp == NULL) | |
874 | return -ENOMEM; | |
875 | ret = -EFAULT; | |
876 | if (!copy_from_user(tmp, buf, count)) { | |
877 | tmp[count] = 0; | |
878 | ret = printk("%s", tmp); | |
cd140a5c GC |
879 | if (ret > count) |
880 | /* printk can add a prefix */ | |
881 | ret = count; | |
1da177e4 LT |
882 | } |
883 | kfree(tmp); | |
884 | return ret; | |
885 | } | |
886 | ||
62322d25 | 887 | static const struct file_operations kmsg_fops = { |
1da177e4 LT |
888 | .write = kmsg_write, |
889 | }; | |
890 | ||
891 | static int memory_open(struct inode * inode, struct file * filp) | |
892 | { | |
1f439647 JC |
893 | int ret = 0; |
894 | ||
895 | lock_kernel(); | |
1da177e4 LT |
896 | switch (iminor(inode)) { |
897 | case 1: | |
898 | filp->f_op = &mem_fops; | |
5da6185b DH |
899 | filp->f_mapping->backing_dev_info = |
900 | &directly_mappable_cdev_bdi; | |
1da177e4 | 901 | break; |
b781ecb6 | 902 | #ifdef CONFIG_DEVKMEM |
1da177e4 LT |
903 | case 2: |
904 | filp->f_op = &kmem_fops; | |
5da6185b DH |
905 | filp->f_mapping->backing_dev_info = |
906 | &directly_mappable_cdev_bdi; | |
1da177e4 | 907 | break; |
b781ecb6 | 908 | #endif |
1da177e4 LT |
909 | case 3: |
910 | filp->f_op = &null_fops; | |
911 | break; | |
4f911d64 | 912 | #ifdef CONFIG_DEVPORT |
1da177e4 LT |
913 | case 4: |
914 | filp->f_op = &port_fops; | |
915 | break; | |
916 | #endif | |
917 | case 5: | |
918 | filp->f_mapping->backing_dev_info = &zero_bdi; | |
919 | filp->f_op = &zero_fops; | |
920 | break; | |
921 | case 7: | |
922 | filp->f_op = &full_fops; | |
923 | break; | |
924 | case 8: | |
925 | filp->f_op = &random_fops; | |
926 | break; | |
927 | case 9: | |
928 | filp->f_op = &urandom_fops; | |
929 | break; | |
930 | case 11: | |
931 | filp->f_op = &kmsg_fops; | |
932 | break; | |
50b1fdbd VG |
933 | #ifdef CONFIG_CRASH_DUMP |
934 | case 12: | |
935 | filp->f_op = &oldmem_fops; | |
936 | break; | |
937 | #endif | |
1da177e4 | 938 | default: |
1f439647 | 939 | unlock_kernel(); |
1da177e4 LT |
940 | return -ENXIO; |
941 | } | |
942 | if (filp->f_op && filp->f_op->open) | |
1f439647 JC |
943 | ret = filp->f_op->open(inode,filp); |
944 | unlock_kernel(); | |
945 | return ret; | |
1da177e4 LT |
946 | } |
947 | ||
62322d25 | 948 | static const struct file_operations memory_fops = { |
1da177e4 LT |
949 | .open = memory_open, /* just a selector for the real open */ |
950 | }; | |
951 | ||
952 | static const struct { | |
953 | unsigned int minor; | |
954 | char *name; | |
955 | umode_t mode; | |
99ac48f5 | 956 | const struct file_operations *fops; |
1da177e4 LT |
957 | } devlist[] = { /* list of minor devices */ |
958 | {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops}, | |
b781ecb6 | 959 | #ifdef CONFIG_DEVKMEM |
1da177e4 | 960 | {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops}, |
b781ecb6 | 961 | #endif |
1da177e4 | 962 | {3, "null", S_IRUGO | S_IWUGO, &null_fops}, |
4f911d64 | 963 | #ifdef CONFIG_DEVPORT |
1da177e4 LT |
964 | {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops}, |
965 | #endif | |
966 | {5, "zero", S_IRUGO | S_IWUGO, &zero_fops}, | |
967 | {7, "full", S_IRUGO | S_IWUGO, &full_fops}, | |
968 | {8, "random", S_IRUGO | S_IWUSR, &random_fops}, | |
969 | {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops}, | |
970 | {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops}, | |
50b1fdbd VG |
971 | #ifdef CONFIG_CRASH_DUMP |
972 | {12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops}, | |
973 | #endif | |
1da177e4 LT |
974 | }; |
975 | ||
ca8eca68 | 976 | static struct class *mem_class; |
1da177e4 LT |
977 | |
978 | static int __init chr_dev_init(void) | |
979 | { | |
980 | int i; | |
e0bf68dd PZ |
981 | int err; |
982 | ||
983 | err = bdi_init(&zero_bdi); | |
984 | if (err) | |
985 | return err; | |
1da177e4 LT |
986 | |
987 | if (register_chrdev(MEM_MAJOR,"mem",&memory_fops)) | |
988 | printk("unable to get major %d for memory devs\n", MEM_MAJOR); | |
989 | ||
ca8eca68 | 990 | mem_class = class_create(THIS_MODULE, "mem"); |
7c69ef79 | 991 | for (i = 0; i < ARRAY_SIZE(devlist); i++) |
03457cd4 GKH |
992 | device_create(mem_class, NULL, |
993 | MKDEV(MEM_MAJOR, devlist[i].minor), NULL, | |
994 | devlist[i].name); | |
ebf644c4 | 995 | |
1da177e4 LT |
996 | return 0; |
997 | } | |
998 | ||
999 | fs_initcall(chr_dev_init); |