Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/drivers/char/mem.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
d7d4d849 | 6 | * Added devfs support. |
1da177e4 | 7 | * Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu> |
af901ca1 | 8 | * Shared /dev/zero mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com> |
1da177e4 LT |
9 | */ |
10 | ||
1da177e4 LT |
11 | #include <linux/mm.h> |
12 | #include <linux/miscdevice.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/vmalloc.h> | |
15 | #include <linux/mman.h> | |
16 | #include <linux/random.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/raw.h> | |
19 | #include <linux/tty.h> | |
20 | #include <linux/capability.h> | |
1da177e4 LT |
21 | #include <linux/ptrace.h> |
22 | #include <linux/device.h> | |
50b1fdbd 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> |
66300e66 | 29 | #include <linux/export.h> |
e1612de9 | 30 | #include <linux/io.h> |
a27bb332 | 31 | #include <linux/aio.h> |
1da177e4 LT |
32 | |
33 | #include <asm/uaccess.h> | |
1da177e4 LT |
34 | |
35 | #ifdef CONFIG_IA64 | |
36 | # include <linux/efi.h> | |
37 | #endif | |
38 | ||
e1612de9 HM |
39 | #define DEVPORT_MINOR 4 |
40 | ||
f222318e WF |
41 | static inline unsigned long size_inside_page(unsigned long start, |
42 | unsigned long size) | |
43 | { | |
44 | unsigned long sz; | |
45 | ||
7fabaddd | 46 | sz = PAGE_SIZE - (start & (PAGE_SIZE - 1)); |
f222318e | 47 | |
7fabaddd | 48 | return min(sz, size); |
f222318e WF |
49 | } |
50 | ||
1da177e4 | 51 | #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE |
7e6735c3 | 52 | static inline int valid_phys_addr_range(phys_addr_t addr, size_t count) |
1da177e4 | 53 | { |
cfaf346c | 54 | return addr + count <= __pa(high_memory); |
1da177e4 | 55 | } |
80851ef2 | 56 | |
06c67bef | 57 | static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) |
80851ef2 BH |
58 | { |
59 | return 1; | |
60 | } | |
1da177e4 LT |
61 | #endif |
62 | ||
d092633b | 63 | #ifdef CONFIG_STRICT_DEVMEM |
e2beb3ea | 64 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 | 65 | { |
e2beb3ea VP |
66 | u64 from = ((u64)pfn) << PAGE_SHIFT; |
67 | u64 to = from + size; | |
68 | u64 cursor = from; | |
69 | ||
70 | while (cursor < to) { | |
1eae225e | 71 | if (!devmem_is_allowed(pfn)) |
ae531c26 | 72 | return 0; |
e2beb3ea VP |
73 | cursor += PAGE_SIZE; |
74 | pfn++; | |
ae531c26 AV |
75 | } |
76 | return 1; | |
77 | } | |
78 | #else | |
e2beb3ea | 79 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 AV |
80 | { |
81 | return 1; | |
82 | } | |
83 | #endif | |
84 | ||
d7d4d849 | 85 | void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr) |
e045fb2a | 86 | { |
87 | } | |
88 | ||
1da177e4 | 89 | /* |
d7d4d849 AM |
90 | * This funcion reads the *physical* memory. The f_pos points directly to the |
91 | * memory location. | |
1da177e4 | 92 | */ |
d7d4d849 | 93 | static ssize_t read_mem(struct file *file, char __user *buf, |
1da177e4 LT |
94 | size_t count, loff_t *ppos) |
95 | { | |
7e6735c3 | 96 | phys_addr_t p = *ppos; |
1da177e4 LT |
97 | ssize_t read, sz; |
98 | char *ptr; | |
99 | ||
136939a2 | 100 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
101 | return -EFAULT; |
102 | read = 0; | |
103 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
104 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
105 | if (p < PAGE_SIZE) { | |
7fabaddd | 106 | sz = size_inside_page(p, count); |
1da177e4 LT |
107 | if (sz > 0) { |
108 | if (clear_user(buf, sz)) | |
109 | return -EFAULT; | |
d7d4d849 AM |
110 | buf += sz; |
111 | p += sz; | |
112 | count -= sz; | |
113 | read += sz; | |
1da177e4 LT |
114 | } |
115 | } | |
116 | #endif | |
117 | ||
118 | while (count > 0) { | |
fa29e97b WF |
119 | unsigned long remaining; |
120 | ||
f222318e | 121 | sz = size_inside_page(p, count); |
1da177e4 | 122 | |
e045fb2a | 123 | if (!range_is_allowed(p >> PAGE_SHIFT, count)) |
124 | return -EPERM; | |
125 | ||
1da177e4 | 126 | /* |
d7d4d849 AM |
127 | * On ia64 if a page has been mapped somewhere as uncached, then |
128 | * it must also be accessed uncached by the kernel or data | |
129 | * corruption may occur. | |
1da177e4 LT |
130 | */ |
131 | ptr = xlate_dev_mem_ptr(p); | |
e045fb2a | 132 | if (!ptr) |
133 | return -EFAULT; | |
1da177e4 | 134 | |
fa29e97b | 135 | remaining = copy_to_user(buf, ptr, sz); |
e045fb2a | 136 | unxlate_dev_mem_ptr(p, ptr); |
fa29e97b WF |
137 | if (remaining) |
138 | return -EFAULT; | |
e045fb2a | 139 | |
1da177e4 LT |
140 | buf += sz; |
141 | p += sz; | |
142 | count -= sz; | |
143 | read += sz; | |
144 | } | |
145 | ||
146 | *ppos += read; | |
147 | return read; | |
148 | } | |
149 | ||
d7d4d849 | 150 | static ssize_t write_mem(struct file *file, const char __user *buf, |
1da177e4 LT |
151 | size_t count, loff_t *ppos) |
152 | { | |
7e6735c3 | 153 | phys_addr_t p = *ppos; |
1da177e4 LT |
154 | ssize_t written, sz; |
155 | unsigned long copied; | |
156 | void *ptr; | |
157 | ||
136939a2 | 158 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
159 | return -EFAULT; |
160 | ||
161 | written = 0; | |
162 | ||
163 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
164 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
165 | if (p < PAGE_SIZE) { | |
7fabaddd | 166 | sz = size_inside_page(p, count); |
1da177e4 LT |
167 | /* Hmm. Do something? */ |
168 | buf += sz; | |
169 | p += sz; | |
170 | count -= sz; | |
171 | written += sz; | |
172 | } | |
173 | #endif | |
174 | ||
175 | while (count > 0) { | |
f222318e | 176 | sz = size_inside_page(p, count); |
1da177e4 | 177 | |
e045fb2a | 178 | if (!range_is_allowed(p >> PAGE_SHIFT, sz)) |
179 | return -EPERM; | |
180 | ||
1da177e4 | 181 | /* |
d7d4d849 AM |
182 | * On ia64 if a page has been mapped somewhere as uncached, then |
183 | * it must also be accessed uncached by the kernel or data | |
184 | * corruption may occur. | |
1da177e4 LT |
185 | */ |
186 | ptr = xlate_dev_mem_ptr(p); | |
e045fb2a | 187 | if (!ptr) { |
188 | if (written) | |
189 | break; | |
190 | return -EFAULT; | |
191 | } | |
1da177e4 LT |
192 | |
193 | copied = copy_from_user(ptr, buf, sz); | |
fa29e97b | 194 | unxlate_dev_mem_ptr(p, ptr); |
1da177e4 | 195 | if (copied) { |
c654d60e JB |
196 | written += sz - copied; |
197 | if (written) | |
198 | break; | |
1da177e4 LT |
199 | return -EFAULT; |
200 | } | |
e045fb2a | 201 | |
1da177e4 LT |
202 | buf += sz; |
203 | p += sz; | |
204 | count -= sz; | |
205 | written += sz; | |
206 | } | |
207 | ||
208 | *ppos += written; | |
209 | return written; | |
210 | } | |
211 | ||
d7d4d849 | 212 | int __weak phys_mem_access_prot_allowed(struct file *file, |
f0970c13 | 213 | unsigned long pfn, unsigned long size, pgprot_t *vma_prot) |
214 | { | |
215 | return 1; | |
216 | } | |
217 | ||
44ac8413 | 218 | #ifndef __HAVE_PHYS_MEM_ACCESS_PROT |
d7d4d849 AM |
219 | |
220 | /* | |
221 | * Architectures vary in how they handle caching for addresses | |
222 | * outside of main memory. | |
223 | * | |
224 | */ | |
ea56f411 | 225 | #ifdef pgprot_noncached |
7e6735c3 | 226 | static int uncached_access(struct file *file, phys_addr_t addr) |
d7d4d849 AM |
227 | { |
228 | #if defined(CONFIG_IA64) | |
229 | /* | |
230 | * On ia64, we ignore O_DSYNC because we cannot tolerate memory | |
231 | * attribute aliases. | |
232 | */ | |
233 | return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); | |
234 | #elif defined(CONFIG_MIPS) | |
235 | { | |
236 | extern int __uncached_access(struct file *file, | |
237 | unsigned long addr); | |
238 | ||
239 | return __uncached_access(file, addr); | |
240 | } | |
241 | #else | |
242 | /* | |
243 | * Accessing memory above the top the kernel knows about or through a | |
244 | * file pointer | |
245 | * that was marked O_DSYNC will be done non-cached. | |
246 | */ | |
247 | if (file->f_flags & O_DSYNC) | |
248 | return 1; | |
249 | return addr >= __pa(high_memory); | |
250 | #endif | |
251 | } | |
ea56f411 | 252 | #endif |
d7d4d849 | 253 | |
44ac8413 BH |
254 | static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, |
255 | unsigned long size, pgprot_t vma_prot) | |
256 | { | |
257 | #ifdef pgprot_noncached | |
7e6735c3 | 258 | phys_addr_t offset = pfn << PAGE_SHIFT; |
44ac8413 BH |
259 | |
260 | if (uncached_access(file, offset)) | |
261 | return pgprot_noncached(vma_prot); | |
262 | #endif | |
263 | return vma_prot; | |
264 | } | |
265 | #endif | |
266 | ||
5da6185b DH |
267 | #ifndef CONFIG_MMU |
268 | static unsigned long get_unmapped_area_mem(struct file *file, | |
269 | unsigned long addr, | |
270 | unsigned long len, | |
271 | unsigned long pgoff, | |
272 | unsigned long flags) | |
273 | { | |
274 | if (!valid_mmap_phys_addr_range(pgoff, len)) | |
275 | return (unsigned long) -EINVAL; | |
8a93258c | 276 | return pgoff << PAGE_SHIFT; |
5da6185b DH |
277 | } |
278 | ||
279 | /* can't do an in-place private mapping if there's no MMU */ | |
280 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
281 | { | |
282 | return vma->vm_flags & VM_MAYSHARE; | |
283 | } | |
284 | #else | |
285 | #define get_unmapped_area_mem NULL | |
286 | ||
287 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
288 | { | |
289 | return 1; | |
290 | } | |
291 | #endif | |
292 | ||
f0f37e2f | 293 | static const struct vm_operations_struct mmap_mem_ops = { |
7ae8ed50 RR |
294 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
295 | .access = generic_access_phys | |
296 | #endif | |
e7f260a2 | 297 | }; |
298 | ||
d7d4d849 | 299 | static int mmap_mem(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 300 | { |
80851ef2 BH |
301 | size_t size = vma->vm_end - vma->vm_start; |
302 | ||
06c67bef | 303 | if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) |
80851ef2 BH |
304 | return -EINVAL; |
305 | ||
5da6185b DH |
306 | if (!private_mapping_ok(vma)) |
307 | return -ENOSYS; | |
308 | ||
e2beb3ea VP |
309 | if (!range_is_allowed(vma->vm_pgoff, size)) |
310 | return -EPERM; | |
311 | ||
f0970c13 | 312 | if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, |
313 | &vma->vm_page_prot)) | |
314 | return -EINVAL; | |
315 | ||
8b150478 | 316 | vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, |
80851ef2 | 317 | size, |
1da177e4 | 318 | vma->vm_page_prot); |
1da177e4 | 319 | |
e7f260a2 | 320 | vma->vm_ops = &mmap_mem_ops; |
321 | ||
314e51b9 | 322 | /* Remap-pfn-range will mark the range VM_IO */ |
1da177e4 LT |
323 | if (remap_pfn_range(vma, |
324 | vma->vm_start, | |
325 | vma->vm_pgoff, | |
80851ef2 | 326 | size, |
e7f260a2 | 327 | vma->vm_page_prot)) { |
1da177e4 | 328 | return -EAGAIN; |
e7f260a2 | 329 | } |
1da177e4 LT |
330 | return 0; |
331 | } | |
332 | ||
b781ecb6 | 333 | #ifdef CONFIG_DEVKMEM |
d7d4d849 | 334 | static int mmap_kmem(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 335 | { |
4bb82551 LT |
336 | unsigned long pfn; |
337 | ||
6d3154cc LT |
338 | /* Turn a kernel-virtual address into a physical page frame */ |
339 | pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; | |
4bb82551 | 340 | |
1da177e4 | 341 | /* |
d7d4d849 AM |
342 | * RED-PEN: on some architectures there is more mapped memory than |
343 | * available in mem_map which pfn_valid checks for. Perhaps should add a | |
344 | * new macro here. | |
1da177e4 LT |
345 | * |
346 | * RED-PEN: vmalloc is not supported right now. | |
347 | */ | |
4bb82551 | 348 | if (!pfn_valid(pfn)) |
1da177e4 | 349 | return -EIO; |
4bb82551 LT |
350 | |
351 | vma->vm_pgoff = pfn; | |
1da177e4 LT |
352 | return mmap_mem(file, vma); |
353 | } | |
b781ecb6 | 354 | #endif |
1da177e4 | 355 | |
50b1fdbd VG |
356 | #ifdef CONFIG_CRASH_DUMP |
357 | /* | |
358 | * Read memory corresponding to the old kernel. | |
50b1fdbd | 359 | */ |
315c215c | 360 | static ssize_t read_oldmem(struct file *file, char __user *buf, |
50b1fdbd VG |
361 | size_t count, loff_t *ppos) |
362 | { | |
315c215c VG |
363 | unsigned long pfn, offset; |
364 | size_t read = 0, csize; | |
365 | int rc = 0; | |
50b1fdbd | 366 | |
72414d3f | 367 | while (count) { |
50b1fdbd | 368 | pfn = *ppos / PAGE_SIZE; |
315c215c VG |
369 | if (pfn > saved_max_pfn) |
370 | return read; | |
50b1fdbd | 371 | |
315c215c VG |
372 | offset = (unsigned long)(*ppos % PAGE_SIZE); |
373 | if (count > PAGE_SIZE - offset) | |
374 | csize = PAGE_SIZE - offset; | |
375 | else | |
376 | csize = count; | |
50b1fdbd | 377 | |
315c215c VG |
378 | rc = copy_oldmem_page(pfn, buf, csize, offset, 1); |
379 | if (rc < 0) | |
380 | return rc; | |
50b1fdbd VG |
381 | buf += csize; |
382 | *ppos += csize; | |
383 | read += csize; | |
384 | count -= csize; | |
385 | } | |
50b1fdbd VG |
386 | return read; |
387 | } | |
388 | #endif | |
1da177e4 | 389 | |
b781ecb6 | 390 | #ifdef CONFIG_DEVKMEM |
1da177e4 LT |
391 | /* |
392 | * This function reads the *virtual* memory as seen by the kernel. | |
393 | */ | |
d7d4d849 | 394 | static ssize_t read_kmem(struct file *file, char __user *buf, |
1da177e4 LT |
395 | size_t count, loff_t *ppos) |
396 | { | |
397 | unsigned long p = *ppos; | |
398 | ssize_t low_count, read, sz; | |
890537b3 | 399 | char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ |
325fda71 | 400 | int err = 0; |
1da177e4 LT |
401 | |
402 | read = 0; | |
403 | if (p < (unsigned long) high_memory) { | |
404 | low_count = count; | |
d7d4d849 AM |
405 | if (count > (unsigned long)high_memory - p) |
406 | low_count = (unsigned long)high_memory - p; | |
1da177e4 LT |
407 | |
408 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
409 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
410 | if (p < PAGE_SIZE && low_count > 0) { | |
7fabaddd WF |
411 | sz = size_inside_page(p, low_count); |
412 | if (clear_user(buf, sz)) | |
1da177e4 | 413 | return -EFAULT; |
7fabaddd WF |
414 | buf += sz; |
415 | p += sz; | |
416 | read += sz; | |
417 | low_count -= sz; | |
418 | count -= sz; | |
1da177e4 LT |
419 | } |
420 | #endif | |
421 | while (low_count > 0) { | |
f222318e | 422 | sz = size_inside_page(p, low_count); |
1da177e4 LT |
423 | |
424 | /* | |
425 | * On ia64 if a page has been mapped somewhere as | |
426 | * uncached, then it must also be accessed uncached | |
427 | * by the kernel or data corruption may occur | |
428 | */ | |
429 | kbuf = xlate_dev_kmem_ptr((char *)p); | |
430 | ||
431 | if (copy_to_user(buf, kbuf, sz)) | |
432 | return -EFAULT; | |
433 | buf += sz; | |
434 | p += sz; | |
435 | read += sz; | |
436 | low_count -= sz; | |
437 | count -= sz; | |
438 | } | |
439 | } | |
440 | ||
441 | if (count > 0) { | |
442 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
443 | if (!kbuf) | |
444 | return -ENOMEM; | |
445 | while (count > 0) { | |
80ad89a0 | 446 | sz = size_inside_page(p, count); |
325fda71 KH |
447 | if (!is_vmalloc_or_module_addr((void *)p)) { |
448 | err = -ENXIO; | |
449 | break; | |
450 | } | |
80ad89a0 WF |
451 | sz = vread(kbuf, (char *)p, sz); |
452 | if (!sz) | |
1da177e4 | 453 | break; |
80ad89a0 | 454 | if (copy_to_user(buf, kbuf, sz)) { |
325fda71 KH |
455 | err = -EFAULT; |
456 | break; | |
1da177e4 | 457 | } |
80ad89a0 WF |
458 | count -= sz; |
459 | buf += sz; | |
460 | read += sz; | |
461 | p += sz; | |
1da177e4 LT |
462 | } |
463 | free_page((unsigned long)kbuf); | |
464 | } | |
325fda71 KH |
465 | *ppos = p; |
466 | return read ? read : err; | |
1da177e4 LT |
467 | } |
468 | ||
469 | ||
d7d4d849 AM |
470 | static ssize_t do_write_kmem(unsigned long p, const char __user *buf, |
471 | size_t count, loff_t *ppos) | |
1da177e4 LT |
472 | { |
473 | ssize_t written, sz; | |
474 | unsigned long copied; | |
475 | ||
476 | written = 0; | |
477 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
478 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
ee32398f WF |
479 | if (p < PAGE_SIZE) { |
480 | sz = size_inside_page(p, count); | |
1da177e4 LT |
481 | /* Hmm. Do something? */ |
482 | buf += sz; | |
483 | p += sz; | |
1da177e4 LT |
484 | count -= sz; |
485 | written += sz; | |
486 | } | |
487 | #endif | |
488 | ||
489 | while (count > 0) { | |
490 | char *ptr; | |
1da177e4 | 491 | |
ee32398f | 492 | sz = size_inside_page(p, count); |
1da177e4 LT |
493 | |
494 | /* | |
d7d4d849 AM |
495 | * On ia64 if a page has been mapped somewhere as uncached, then |
496 | * it must also be accessed uncached by the kernel or data | |
497 | * corruption may occur. | |
1da177e4 | 498 | */ |
ee32398f | 499 | ptr = xlate_dev_kmem_ptr((char *)p); |
1da177e4 LT |
500 | |
501 | copied = copy_from_user(ptr, buf, sz); | |
502 | if (copied) { | |
c654d60e JB |
503 | written += sz - copied; |
504 | if (written) | |
505 | break; | |
1da177e4 LT |
506 | return -EFAULT; |
507 | } | |
508 | buf += sz; | |
509 | p += sz; | |
1da177e4 LT |
510 | count -= sz; |
511 | written += sz; | |
512 | } | |
513 | ||
514 | *ppos += written; | |
515 | return written; | |
516 | } | |
517 | ||
1da177e4 LT |
518 | /* |
519 | * This function writes to the *virtual* memory as seen by the kernel. | |
520 | */ | |
d7d4d849 | 521 | static ssize_t write_kmem(struct file *file, const char __user *buf, |
1da177e4 LT |
522 | size_t count, loff_t *ppos) |
523 | { | |
524 | unsigned long p = *ppos; | |
525 | ssize_t wrote = 0; | |
526 | ssize_t virtr = 0; | |
890537b3 | 527 | char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ |
325fda71 | 528 | int err = 0; |
1da177e4 LT |
529 | |
530 | if (p < (unsigned long) high_memory) { | |
80ad89a0 WF |
531 | unsigned long to_write = min_t(unsigned long, count, |
532 | (unsigned long)high_memory - p); | |
ee32398f | 533 | wrote = do_write_kmem(p, buf, to_write, ppos); |
80ad89a0 WF |
534 | if (wrote != to_write) |
535 | return wrote; | |
1da177e4 LT |
536 | p += wrote; |
537 | buf += wrote; | |
538 | count -= wrote; | |
539 | } | |
540 | ||
541 | if (count > 0) { | |
542 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
543 | if (!kbuf) | |
544 | return wrote ? wrote : -ENOMEM; | |
545 | while (count > 0) { | |
80ad89a0 WF |
546 | unsigned long sz = size_inside_page(p, count); |
547 | unsigned long n; | |
1da177e4 | 548 | |
325fda71 KH |
549 | if (!is_vmalloc_or_module_addr((void *)p)) { |
550 | err = -ENXIO; | |
551 | break; | |
552 | } | |
80ad89a0 WF |
553 | n = copy_from_user(kbuf, buf, sz); |
554 | if (n) { | |
325fda71 KH |
555 | err = -EFAULT; |
556 | break; | |
1da177e4 | 557 | } |
c85e9a97 | 558 | vwrite(kbuf, (char *)p, sz); |
80ad89a0 WF |
559 | count -= sz; |
560 | buf += sz; | |
561 | virtr += sz; | |
562 | p += sz; | |
1da177e4 LT |
563 | } |
564 | free_page((unsigned long)kbuf); | |
565 | } | |
566 | ||
325fda71 KH |
567 | *ppos = p; |
568 | return virtr + wrote ? : err; | |
1da177e4 | 569 | } |
b781ecb6 | 570 | #endif |
1da177e4 | 571 | |
4f911d64 | 572 | #ifdef CONFIG_DEVPORT |
d7d4d849 | 573 | static ssize_t read_port(struct file *file, char __user *buf, |
1da177e4 LT |
574 | size_t count, loff_t *ppos) |
575 | { | |
576 | unsigned long i = *ppos; | |
577 | char __user *tmp = buf; | |
578 | ||
579 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
d7d4d849 | 580 | return -EFAULT; |
1da177e4 | 581 | while (count-- > 0 && i < 65536) { |
d7d4d849 AM |
582 | if (__put_user(inb(i), tmp) < 0) |
583 | return -EFAULT; | |
1da177e4 LT |
584 | i++; |
585 | tmp++; | |
586 | } | |
587 | *ppos = i; | |
588 | return tmp-buf; | |
589 | } | |
590 | ||
d7d4d849 | 591 | static ssize_t write_port(struct file *file, const char __user *buf, |
1da177e4 LT |
592 | size_t count, loff_t *ppos) |
593 | { | |
594 | unsigned long i = *ppos; | |
890537b3 | 595 | const char __user *tmp = buf; |
1da177e4 | 596 | |
d7d4d849 | 597 | if (!access_ok(VERIFY_READ, buf, count)) |
1da177e4 LT |
598 | return -EFAULT; |
599 | while (count-- > 0 && i < 65536) { | |
600 | char c; | |
c654d60e JB |
601 | if (__get_user(c, tmp)) { |
602 | if (tmp > buf) | |
603 | break; | |
d7d4d849 | 604 | return -EFAULT; |
c654d60e | 605 | } |
d7d4d849 | 606 | outb(c, i); |
1da177e4 LT |
607 | i++; |
608 | tmp++; | |
609 | } | |
610 | *ppos = i; | |
611 | return tmp-buf; | |
612 | } | |
613 | #endif | |
614 | ||
d7d4d849 | 615 | static ssize_t read_null(struct file *file, char __user *buf, |
1da177e4 LT |
616 | size_t count, loff_t *ppos) |
617 | { | |
618 | return 0; | |
619 | } | |
620 | ||
d7d4d849 | 621 | static ssize_t write_null(struct file *file, const char __user *buf, |
1da177e4 LT |
622 | size_t count, loff_t *ppos) |
623 | { | |
624 | return count; | |
625 | } | |
626 | ||
162934de ZB |
627 | static ssize_t aio_read_null(struct kiocb *iocb, const struct iovec *iov, |
628 | unsigned long nr_segs, loff_t pos) | |
629 | { | |
630 | return 0; | |
631 | } | |
632 | ||
633 | static ssize_t aio_write_null(struct kiocb *iocb, const struct iovec *iov, | |
634 | unsigned long nr_segs, loff_t pos) | |
635 | { | |
636 | return iov_length(iov, nr_segs); | |
637 | } | |
638 | ||
1ebd32fc JA |
639 | static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, |
640 | struct splice_desc *sd) | |
641 | { | |
642 | return sd->len; | |
643 | } | |
644 | ||
d7d4d849 | 645 | static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out, |
1ebd32fc JA |
646 | loff_t *ppos, size_t len, unsigned int flags) |
647 | { | |
648 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); | |
649 | } | |
650 | ||
d7d4d849 | 651 | static ssize_t read_zero(struct file *file, char __user *buf, |
1da177e4 LT |
652 | size_t count, loff_t *ppos) |
653 | { | |
557ed1fa | 654 | size_t written; |
1da177e4 LT |
655 | |
656 | if (!count) | |
657 | return 0; | |
658 | ||
659 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
660 | return -EFAULT; | |
661 | ||
557ed1fa NP |
662 | written = 0; |
663 | while (count) { | |
664 | unsigned long unwritten; | |
665 | size_t chunk = count; | |
1da177e4 | 666 | |
557ed1fa NP |
667 | if (chunk > PAGE_SIZE) |
668 | chunk = PAGE_SIZE; /* Just for latency reasons */ | |
bb521c5d | 669 | unwritten = __clear_user(buf, chunk); |
557ed1fa | 670 | written += chunk - unwritten; |
1da177e4 | 671 | if (unwritten) |
557ed1fa | 672 | break; |
2b838687 LT |
673 | if (signal_pending(current)) |
674 | return written ? written : -ERESTARTSYS; | |
1da177e4 | 675 | buf += chunk; |
557ed1fa | 676 | count -= chunk; |
1da177e4 LT |
677 | cond_resched(); |
678 | } | |
557ed1fa | 679 | return written ? written : -EFAULT; |
1da177e4 LT |
680 | } |
681 | ||
162934de ZB |
682 | static ssize_t aio_read_zero(struct kiocb *iocb, const struct iovec *iov, |
683 | unsigned long nr_segs, loff_t pos) | |
684 | { | |
685 | size_t written = 0; | |
686 | unsigned long i; | |
687 | ssize_t ret; | |
688 | ||
689 | for (i = 0; i < nr_segs; i++) { | |
690 | ret = read_zero(iocb->ki_filp, iov[i].iov_base, iov[i].iov_len, | |
691 | &pos); | |
692 | if (ret < 0) | |
693 | break; | |
694 | written += ret; | |
695 | } | |
696 | ||
697 | return written ? written : -EFAULT; | |
698 | } | |
699 | ||
d7d4d849 | 700 | static int mmap_zero(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 701 | { |
557ed1fa | 702 | #ifndef CONFIG_MMU |
1da177e4 | 703 | return -ENOSYS; |
557ed1fa NP |
704 | #endif |
705 | if (vma->vm_flags & VM_SHARED) | |
706 | return shmem_zero_setup(vma); | |
707 | return 0; | |
1da177e4 | 708 | } |
1da177e4 | 709 | |
d7d4d849 | 710 | static ssize_t write_full(struct file *file, const char __user *buf, |
1da177e4 LT |
711 | size_t count, loff_t *ppos) |
712 | { | |
713 | return -ENOSPC; | |
714 | } | |
715 | ||
716 | /* | |
717 | * Special lseek() function for /dev/null and /dev/zero. Most notably, you | |
718 | * can fopen() both devices with "a" now. This was previously impossible. | |
719 | * -- SRB. | |
720 | */ | |
d7d4d849 | 721 | static loff_t null_lseek(struct file *file, loff_t offset, int orig) |
1da177e4 LT |
722 | { |
723 | return file->f_pos = 0; | |
724 | } | |
725 | ||
726 | /* | |
727 | * The memory devices use the full 32/64 bits of the offset, and so we cannot | |
728 | * check against negative addresses: they are ok. The return value is weird, | |
729 | * though, in that case (0). | |
730 | * | |
731 | * also note that seeking relative to the "end of file" isn't supported: | |
732 | * it has no meaning, so it returns -EINVAL. | |
733 | */ | |
d7d4d849 | 734 | static loff_t memory_lseek(struct file *file, loff_t offset, int orig) |
1da177e4 LT |
735 | { |
736 | loff_t ret; | |
737 | ||
496ad9aa | 738 | mutex_lock(&file_inode(file)->i_mutex); |
1da177e4 | 739 | switch (orig) { |
d7d4d849 AM |
740 | case SEEK_CUR: |
741 | offset += file->f_pos; | |
d7d4d849 AM |
742 | case SEEK_SET: |
743 | /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */ | |
744 | if ((unsigned long long)offset >= ~0xFFFULL) { | |
745 | ret = -EOVERFLOW; | |
1da177e4 | 746 | break; |
d7d4d849 AM |
747 | } |
748 | file->f_pos = offset; | |
749 | ret = file->f_pos; | |
750 | force_successful_syscall_return(); | |
751 | break; | |
752 | default: | |
753 | ret = -EINVAL; | |
1da177e4 | 754 | } |
496ad9aa | 755 | mutex_unlock(&file_inode(file)->i_mutex); |
1da177e4 LT |
756 | return ret; |
757 | } | |
758 | ||
890537b3 | 759 | static int open_port(struct inode *inode, struct file *filp) |
1da177e4 LT |
760 | { |
761 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; | |
762 | } | |
763 | ||
764 | #define zero_lseek null_lseek | |
765 | #define full_lseek null_lseek | |
766 | #define write_zero write_null | |
767 | #define read_full read_zero | |
162934de | 768 | #define aio_write_zero aio_write_null |
1da177e4 LT |
769 | #define open_mem open_port |
770 | #define open_kmem open_mem | |
50b1fdbd | 771 | #define open_oldmem open_mem |
1da177e4 | 772 | |
62322d25 | 773 | static const struct file_operations mem_fops = { |
1da177e4 LT |
774 | .llseek = memory_lseek, |
775 | .read = read_mem, | |
776 | .write = write_mem, | |
777 | .mmap = mmap_mem, | |
778 | .open = open_mem, | |
5da6185b | 779 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 LT |
780 | }; |
781 | ||
b781ecb6 | 782 | #ifdef CONFIG_DEVKMEM |
62322d25 | 783 | static const struct file_operations kmem_fops = { |
1da177e4 LT |
784 | .llseek = memory_lseek, |
785 | .read = read_kmem, | |
786 | .write = write_kmem, | |
787 | .mmap = mmap_kmem, | |
788 | .open = open_kmem, | |
5da6185b | 789 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 | 790 | }; |
b781ecb6 | 791 | #endif |
1da177e4 | 792 | |
62322d25 | 793 | static const struct file_operations null_fops = { |
1da177e4 LT |
794 | .llseek = null_lseek, |
795 | .read = read_null, | |
796 | .write = write_null, | |
162934de ZB |
797 | .aio_read = aio_read_null, |
798 | .aio_write = aio_write_null, | |
1ebd32fc | 799 | .splice_write = splice_write_null, |
1da177e4 LT |
800 | }; |
801 | ||
4f911d64 | 802 | #ifdef CONFIG_DEVPORT |
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, | |
162934de ZB |
815 | .aio_read = aio_read_zero, |
816 | .aio_write = aio_write_zero, | |
1da177e4 LT |
817 | .mmap = mmap_zero, |
818 | }; | |
819 | ||
5da6185b DH |
820 | /* |
821 | * capabilities for /dev/zero | |
822 | * - permits private mappings, "copies" are taken of the source of zeros | |
371d217e | 823 | * - no writeback happens |
5da6185b | 824 | */ |
1da177e4 | 825 | static struct backing_dev_info zero_bdi = { |
d993831f | 826 | .name = "char/mem", |
371d217e | 827 | .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK, |
1da177e4 LT |
828 | }; |
829 | ||
62322d25 | 830 | static const struct file_operations full_fops = { |
1da177e4 LT |
831 | .llseek = full_lseek, |
832 | .read = read_full, | |
833 | .write = write_full, | |
834 | }; | |
835 | ||
50b1fdbd | 836 | #ifdef CONFIG_CRASH_DUMP |
62322d25 | 837 | static const struct file_operations oldmem_fops = { |
50b1fdbd VG |
838 | .read = read_oldmem, |
839 | .open = open_oldmem, | |
6038f373 | 840 | .llseek = default_llseek, |
50b1fdbd VG |
841 | }; |
842 | #endif | |
843 | ||
389e0cb9 KS |
844 | static const struct memdev { |
845 | const char *name; | |
2c9ede55 | 846 | umode_t mode; |
389e0cb9 KS |
847 | const struct file_operations *fops; |
848 | struct backing_dev_info *dev_info; | |
849 | } devlist[] = { | |
e454cea2 | 850 | [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi }, |
b781ecb6 | 851 | #ifdef CONFIG_DEVKMEM |
e454cea2 | 852 | [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi }, |
b781ecb6 | 853 | #endif |
e454cea2 | 854 | [3] = { "null", 0666, &null_fops, NULL }, |
4f911d64 | 855 | #ifdef CONFIG_DEVPORT |
e454cea2 | 856 | [4] = { "port", 0, &port_fops, NULL }, |
1da177e4 | 857 | #endif |
e454cea2 KS |
858 | [5] = { "zero", 0666, &zero_fops, &zero_bdi }, |
859 | [7] = { "full", 0666, &full_fops, NULL }, | |
860 | [8] = { "random", 0666, &random_fops, NULL }, | |
861 | [9] = { "urandom", 0666, &urandom_fops, NULL }, | |
7f3a781d | 862 | #ifdef CONFIG_PRINTK |
e11fea92 | 863 | [11] = { "kmsg", 0644, &kmsg_fops, NULL }, |
7f3a781d | 864 | #endif |
50b1fdbd | 865 | #ifdef CONFIG_CRASH_DUMP |
e454cea2 | 866 | [12] = { "oldmem", 0, &oldmem_fops, NULL }, |
50b1fdbd | 867 | #endif |
d6f47bef ASF |
868 | }; |
869 | ||
870 | static int memory_open(struct inode *inode, struct file *filp) | |
871 | { | |
389e0cb9 KS |
872 | int minor; |
873 | const struct memdev *dev; | |
d6f47bef | 874 | |
389e0cb9 KS |
875 | minor = iminor(inode); |
876 | if (minor >= ARRAY_SIZE(devlist)) | |
205153aa | 877 | return -ENXIO; |
d6f47bef | 878 | |
389e0cb9 KS |
879 | dev = &devlist[minor]; |
880 | if (!dev->fops) | |
205153aa | 881 | return -ENXIO; |
d6f47bef | 882 | |
389e0cb9 KS |
883 | filp->f_op = dev->fops; |
884 | if (dev->dev_info) | |
885 | filp->f_mapping->backing_dev_info = dev->dev_info; | |
d6f47bef | 886 | |
4a3956c7 KH |
887 | /* Is /dev/mem or /dev/kmem ? */ |
888 | if (dev->dev_info == &directly_mappable_cdev_bdi) | |
889 | filp->f_mode |= FMODE_UNSIGNED_OFFSET; | |
890 | ||
389e0cb9 | 891 | if (dev->fops->open) |
205153aa FW |
892 | return dev->fops->open(inode, filp); |
893 | ||
894 | return 0; | |
1da177e4 LT |
895 | } |
896 | ||
62322d25 | 897 | static const struct file_operations memory_fops = { |
d7d4d849 | 898 | .open = memory_open, |
6038f373 | 899 | .llseek = noop_llseek, |
1da177e4 LT |
900 | }; |
901 | ||
2c9ede55 | 902 | static char *mem_devnode(struct device *dev, umode_t *mode) |
e454cea2 KS |
903 | { |
904 | if (mode && devlist[MINOR(dev->devt)].mode) | |
905 | *mode = devlist[MINOR(dev->devt)].mode; | |
906 | return NULL; | |
907 | } | |
908 | ||
ca8eca68 | 909 | static struct class *mem_class; |
1da177e4 LT |
910 | |
911 | static int __init chr_dev_init(void) | |
912 | { | |
389e0cb9 | 913 | int minor; |
e0bf68dd PZ |
914 | int err; |
915 | ||
916 | err = bdi_init(&zero_bdi); | |
917 | if (err) | |
918 | return err; | |
1da177e4 | 919 | |
d7d4d849 | 920 | if (register_chrdev(MEM_MAJOR, "mem", &memory_fops)) |
1da177e4 LT |
921 | printk("unable to get major %d for memory devs\n", MEM_MAJOR); |
922 | ||
ca8eca68 | 923 | mem_class = class_create(THIS_MODULE, "mem"); |
6e191f7b AB |
924 | if (IS_ERR(mem_class)) |
925 | return PTR_ERR(mem_class); | |
926 | ||
e454cea2 | 927 | mem_class->devnode = mem_devnode; |
389e0cb9 KS |
928 | for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) { |
929 | if (!devlist[minor].name) | |
930 | continue; | |
e1612de9 HM |
931 | |
932 | /* | |
890537b3 | 933 | * Create /dev/port? |
e1612de9 HM |
934 | */ |
935 | if ((minor == DEVPORT_MINOR) && !arch_has_dev_port()) | |
936 | continue; | |
937 | ||
389e0cb9 KS |
938 | device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor), |
939 | NULL, devlist[minor].name); | |
940 | } | |
ebf644c4 | 941 | |
31d1d48e | 942 | return tty_init(); |
1da177e4 LT |
943 | } |
944 | ||
945 | fs_initcall(chr_dev_init); |