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 | ||
6fa3eb70 | 63 | #if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) |
d092633b | 64 | #ifdef CONFIG_STRICT_DEVMEM |
081fb3dc KC |
65 | static inline int page_is_allowed(unsigned long pfn) |
66 | { | |
67 | return devmem_is_allowed(pfn); | |
68 | } | |
e2beb3ea | 69 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 | 70 | { |
e2beb3ea VP |
71 | u64 from = ((u64)pfn) << PAGE_SHIFT; |
72 | u64 to = from + size; | |
73 | u64 cursor = from; | |
74 | ||
75 | while (cursor < to) { | |
1eae225e | 76 | if (!devmem_is_allowed(pfn)) |
ae531c26 | 77 | return 0; |
e2beb3ea VP |
78 | cursor += PAGE_SIZE; |
79 | pfn++; | |
ae531c26 AV |
80 | } |
81 | return 1; | |
82 | } | |
83 | #else | |
081fb3dc KC |
84 | static inline int page_is_allowed(unsigned long pfn) |
85 | { | |
86 | return 1; | |
87 | } | |
e2beb3ea | 88 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 AV |
89 | { |
90 | return 1; | |
91 | } | |
92 | #endif | |
6fa3eb70 | 93 | #endif |
ae531c26 | 94 | |
6fa3eb70 | 95 | #ifdef CONFIG_DEVMEM |
d7d4d849 | 96 | void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr) |
e045fb2a | 97 | { |
98 | } | |
99 | ||
1da177e4 | 100 | /* |
d7d4d849 AM |
101 | * This funcion reads the *physical* memory. The f_pos points directly to the |
102 | * memory location. | |
1da177e4 | 103 | */ |
d7d4d849 | 104 | static ssize_t read_mem(struct file *file, char __user *buf, |
1da177e4 LT |
105 | size_t count, loff_t *ppos) |
106 | { | |
7e6735c3 | 107 | phys_addr_t p = *ppos; |
1da177e4 LT |
108 | ssize_t read, sz; |
109 | char *ptr; | |
110 | ||
136939a2 | 111 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
112 | return -EFAULT; |
113 | read = 0; | |
114 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
115 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
116 | if (p < PAGE_SIZE) { | |
7fabaddd | 117 | sz = size_inside_page(p, count); |
1da177e4 LT |
118 | if (sz > 0) { |
119 | if (clear_user(buf, sz)) | |
120 | return -EFAULT; | |
d7d4d849 AM |
121 | buf += sz; |
122 | p += sz; | |
123 | count -= sz; | |
124 | read += sz; | |
1da177e4 LT |
125 | } |
126 | } | |
127 | #endif | |
128 | ||
129 | while (count > 0) { | |
fa29e97b | 130 | unsigned long remaining; |
081fb3dc | 131 | int allowed; |
fa29e97b | 132 | |
f222318e | 133 | sz = size_inside_page(p, count); |
1da177e4 | 134 | |
081fb3dc KC |
135 | allowed = page_is_allowed(p >> PAGE_SHIFT); |
136 | if (!allowed) | |
e045fb2a | 137 | return -EPERM; |
081fb3dc KC |
138 | if (allowed == 2) { |
139 | /* Show zeros for restricted memory. */ | |
140 | remaining = clear_user(buf, sz); | |
141 | } else { | |
142 | /* | |
143 | * On ia64 if a page has been mapped somewhere as | |
144 | * uncached, then it must also be accessed uncached | |
145 | * by the kernel or data corruption may occur. | |
146 | */ | |
147 | ptr = xlate_dev_mem_ptr(p); | |
148 | if (!ptr) | |
149 | return -EFAULT; | |
e045fb2a | 150 | |
081fb3dc KC |
151 | remaining = copy_to_user(buf, ptr, sz); |
152 | ||
153 | unxlate_dev_mem_ptr(p, ptr); | |
154 | } | |
1da177e4 | 155 | |
fa29e97b WF |
156 | if (remaining) |
157 | return -EFAULT; | |
e045fb2a | 158 | |
1da177e4 LT |
159 | buf += sz; |
160 | p += sz; | |
161 | count -= sz; | |
162 | read += sz; | |
163 | } | |
164 | ||
165 | *ppos += read; | |
166 | return read; | |
167 | } | |
168 | ||
d7d4d849 | 169 | static ssize_t write_mem(struct file *file, const char __user *buf, |
1da177e4 LT |
170 | size_t count, loff_t *ppos) |
171 | { | |
7e6735c3 | 172 | phys_addr_t p = *ppos; |
1da177e4 LT |
173 | ssize_t written, sz; |
174 | unsigned long copied; | |
175 | void *ptr; | |
176 | ||
136939a2 | 177 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
178 | return -EFAULT; |
179 | ||
180 | written = 0; | |
181 | ||
182 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
183 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
184 | if (p < PAGE_SIZE) { | |
7fabaddd | 185 | sz = size_inside_page(p, count); |
1da177e4 LT |
186 | /* Hmm. Do something? */ |
187 | buf += sz; | |
188 | p += sz; | |
189 | count -= sz; | |
190 | written += sz; | |
191 | } | |
192 | #endif | |
193 | ||
194 | while (count > 0) { | |
081fb3dc KC |
195 | int allowed; |
196 | ||
f222318e | 197 | sz = size_inside_page(p, count); |
1da177e4 | 198 | |
081fb3dc KC |
199 | allowed = page_is_allowed(p >> PAGE_SHIFT); |
200 | if (!allowed) | |
e045fb2a | 201 | return -EPERM; |
202 | ||
081fb3dc KC |
203 | /* Skip actual writing when a page is marked as restricted. */ |
204 | if (allowed == 1) { | |
205 | /* | |
206 | * On ia64 if a page has been mapped somewhere as | |
207 | * uncached, then it must also be accessed uncached | |
208 | * by the kernel or data corruption may occur. | |
209 | */ | |
210 | ptr = xlate_dev_mem_ptr(p); | |
211 | if (!ptr) { | |
212 | if (written) | |
213 | break; | |
214 | return -EFAULT; | |
215 | } | |
216 | ||
217 | copied = copy_from_user(ptr, buf, sz); | |
218 | unxlate_dev_mem_ptr(p, ptr); | |
219 | if (copied) { | |
220 | written += sz - copied; | |
221 | if (written) | |
222 | break; | |
223 | return -EFAULT; | |
224 | } | |
1da177e4 | 225 | } |
e045fb2a | 226 | |
1da177e4 LT |
227 | buf += sz; |
228 | p += sz; | |
229 | count -= sz; | |
230 | written += sz; | |
231 | } | |
232 | ||
233 | *ppos += written; | |
234 | return written; | |
235 | } | |
6fa3eb70 S |
236 | #endif /* CONFIG_DEVMEM */ |
237 | ||
238 | #if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) | |
1da177e4 | 239 | |
d7d4d849 | 240 | int __weak phys_mem_access_prot_allowed(struct file *file, |
f0970c13 | 241 | unsigned long pfn, unsigned long size, pgprot_t *vma_prot) |
242 | { | |
243 | return 1; | |
244 | } | |
245 | ||
44ac8413 | 246 | #ifndef __HAVE_PHYS_MEM_ACCESS_PROT |
d7d4d849 AM |
247 | |
248 | /* | |
249 | * Architectures vary in how they handle caching for addresses | |
250 | * outside of main memory. | |
251 | * | |
252 | */ | |
ea56f411 | 253 | #ifdef pgprot_noncached |
7e6735c3 | 254 | static int uncached_access(struct file *file, phys_addr_t addr) |
d7d4d849 AM |
255 | { |
256 | #if defined(CONFIG_IA64) | |
257 | /* | |
258 | * On ia64, we ignore O_DSYNC because we cannot tolerate memory | |
259 | * attribute aliases. | |
260 | */ | |
261 | return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); | |
262 | #elif defined(CONFIG_MIPS) | |
263 | { | |
264 | extern int __uncached_access(struct file *file, | |
265 | unsigned long addr); | |
266 | ||
267 | return __uncached_access(file, addr); | |
268 | } | |
269 | #else | |
270 | /* | |
271 | * Accessing memory above the top the kernel knows about or through a | |
272 | * file pointer | |
273 | * that was marked O_DSYNC will be done non-cached. | |
274 | */ | |
275 | if (file->f_flags & O_DSYNC) | |
276 | return 1; | |
277 | return addr >= __pa(high_memory); | |
278 | #endif | |
279 | } | |
ea56f411 | 280 | #endif |
d7d4d849 | 281 | |
44ac8413 BH |
282 | static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, |
283 | unsigned long size, pgprot_t vma_prot) | |
284 | { | |
285 | #ifdef pgprot_noncached | |
7e6735c3 | 286 | phys_addr_t offset = pfn << PAGE_SHIFT; |
44ac8413 BH |
287 | |
288 | if (uncached_access(file, offset)) | |
289 | return pgprot_noncached(vma_prot); | |
290 | #endif | |
291 | return vma_prot; | |
292 | } | |
293 | #endif | |
294 | ||
5da6185b DH |
295 | #ifndef CONFIG_MMU |
296 | static unsigned long get_unmapped_area_mem(struct file *file, | |
297 | unsigned long addr, | |
298 | unsigned long len, | |
299 | unsigned long pgoff, | |
300 | unsigned long flags) | |
301 | { | |
302 | if (!valid_mmap_phys_addr_range(pgoff, len)) | |
303 | return (unsigned long) -EINVAL; | |
8a93258c | 304 | return pgoff << PAGE_SHIFT; |
5da6185b DH |
305 | } |
306 | ||
307 | /* can't do an in-place private mapping if there's no MMU */ | |
308 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
309 | { | |
310 | return vma->vm_flags & VM_MAYSHARE; | |
311 | } | |
312 | #else | |
313 | #define get_unmapped_area_mem NULL | |
314 | ||
315 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
316 | { | |
317 | return 1; | |
318 | } | |
319 | #endif | |
320 | ||
f0f37e2f | 321 | static const struct vm_operations_struct mmap_mem_ops = { |
7ae8ed50 RR |
322 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
323 | .access = generic_access_phys | |
324 | #endif | |
e7f260a2 | 325 | }; |
326 | ||
d7d4d849 | 327 | static int mmap_mem(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 328 | { |
80851ef2 BH |
329 | size_t size = vma->vm_end - vma->vm_start; |
330 | ||
06c67bef | 331 | if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) |
80851ef2 BH |
332 | return -EINVAL; |
333 | ||
5da6185b DH |
334 | if (!private_mapping_ok(vma)) |
335 | return -ENOSYS; | |
336 | ||
e2beb3ea VP |
337 | if (!range_is_allowed(vma->vm_pgoff, size)) |
338 | return -EPERM; | |
339 | ||
f0970c13 | 340 | if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, |
341 | &vma->vm_page_prot)) | |
342 | return -EINVAL; | |
343 | ||
8b150478 | 344 | vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, |
80851ef2 | 345 | size, |
1da177e4 | 346 | vma->vm_page_prot); |
1da177e4 | 347 | |
e7f260a2 | 348 | vma->vm_ops = &mmap_mem_ops; |
349 | ||
314e51b9 | 350 | /* Remap-pfn-range will mark the range VM_IO */ |
1da177e4 LT |
351 | if (remap_pfn_range(vma, |
352 | vma->vm_start, | |
353 | vma->vm_pgoff, | |
80851ef2 | 354 | size, |
e7f260a2 | 355 | vma->vm_page_prot)) { |
1da177e4 | 356 | return -EAGAIN; |
e7f260a2 | 357 | } |
1da177e4 LT |
358 | return 0; |
359 | } | |
6fa3eb70 | 360 | #endif /* CONFIG_DEVMEM */ |
1da177e4 | 361 | |
b781ecb6 | 362 | #ifdef CONFIG_DEVKMEM |
d7d4d849 | 363 | static int mmap_kmem(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 364 | { |
4bb82551 LT |
365 | unsigned long pfn; |
366 | ||
6d3154cc LT |
367 | /* Turn a kernel-virtual address into a physical page frame */ |
368 | pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; | |
4bb82551 | 369 | |
1da177e4 | 370 | /* |
d7d4d849 AM |
371 | * RED-PEN: on some architectures there is more mapped memory than |
372 | * available in mem_map which pfn_valid checks for. Perhaps should add a | |
373 | * new macro here. | |
1da177e4 LT |
374 | * |
375 | * RED-PEN: vmalloc is not supported right now. | |
376 | */ | |
4bb82551 | 377 | if (!pfn_valid(pfn)) |
1da177e4 | 378 | return -EIO; |
4bb82551 LT |
379 | |
380 | vma->vm_pgoff = pfn; | |
1da177e4 LT |
381 | return mmap_mem(file, vma); |
382 | } | |
b781ecb6 | 383 | #endif |
1da177e4 | 384 | |
50b1fdbd VG |
385 | #ifdef CONFIG_CRASH_DUMP |
386 | /* | |
387 | * Read memory corresponding to the old kernel. | |
50b1fdbd | 388 | */ |
315c215c | 389 | static ssize_t read_oldmem(struct file *file, char __user *buf, |
50b1fdbd VG |
390 | size_t count, loff_t *ppos) |
391 | { | |
315c215c VG |
392 | unsigned long pfn, offset; |
393 | size_t read = 0, csize; | |
394 | int rc = 0; | |
50b1fdbd | 395 | |
72414d3f | 396 | while (count) { |
50b1fdbd | 397 | pfn = *ppos / PAGE_SIZE; |
315c215c VG |
398 | if (pfn > saved_max_pfn) |
399 | return read; | |
50b1fdbd | 400 | |
315c215c VG |
401 | offset = (unsigned long)(*ppos % PAGE_SIZE); |
402 | if (count > PAGE_SIZE - offset) | |
403 | csize = PAGE_SIZE - offset; | |
404 | else | |
405 | csize = count; | |
50b1fdbd | 406 | |
315c215c VG |
407 | rc = copy_oldmem_page(pfn, buf, csize, offset, 1); |
408 | if (rc < 0) | |
409 | return rc; | |
50b1fdbd VG |
410 | buf += csize; |
411 | *ppos += csize; | |
412 | read += csize; | |
413 | count -= csize; | |
414 | } | |
50b1fdbd VG |
415 | return read; |
416 | } | |
417 | #endif | |
1da177e4 | 418 | |
b781ecb6 | 419 | #ifdef CONFIG_DEVKMEM |
1da177e4 LT |
420 | /* |
421 | * This function reads the *virtual* memory as seen by the kernel. | |
422 | */ | |
d7d4d849 | 423 | static ssize_t read_kmem(struct file *file, char __user *buf, |
1da177e4 LT |
424 | size_t count, loff_t *ppos) |
425 | { | |
426 | unsigned long p = *ppos; | |
427 | ssize_t low_count, read, sz; | |
890537b3 | 428 | char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ |
325fda71 | 429 | int err = 0; |
1da177e4 LT |
430 | |
431 | read = 0; | |
432 | if (p < (unsigned long) high_memory) { | |
433 | low_count = count; | |
d7d4d849 AM |
434 | if (count > (unsigned long)high_memory - p) |
435 | low_count = (unsigned long)high_memory - p; | |
1da177e4 LT |
436 | |
437 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
438 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
439 | if (p < PAGE_SIZE && low_count > 0) { | |
7fabaddd WF |
440 | sz = size_inside_page(p, low_count); |
441 | if (clear_user(buf, sz)) | |
1da177e4 | 442 | return -EFAULT; |
7fabaddd WF |
443 | buf += sz; |
444 | p += sz; | |
445 | read += sz; | |
446 | low_count -= sz; | |
447 | count -= sz; | |
1da177e4 LT |
448 | } |
449 | #endif | |
450 | while (low_count > 0) { | |
f222318e | 451 | sz = size_inside_page(p, low_count); |
1da177e4 LT |
452 | |
453 | /* | |
454 | * On ia64 if a page has been mapped somewhere as | |
455 | * uncached, then it must also be accessed uncached | |
456 | * by the kernel or data corruption may occur | |
457 | */ | |
458 | kbuf = xlate_dev_kmem_ptr((char *)p); | |
459 | ||
460 | if (copy_to_user(buf, kbuf, sz)) | |
461 | return -EFAULT; | |
462 | buf += sz; | |
463 | p += sz; | |
464 | read += sz; | |
465 | low_count -= sz; | |
466 | count -= sz; | |
467 | } | |
468 | } | |
469 | ||
470 | if (count > 0) { | |
471 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
472 | if (!kbuf) | |
473 | return -ENOMEM; | |
474 | while (count > 0) { | |
80ad89a0 | 475 | sz = size_inside_page(p, count); |
325fda71 KH |
476 | if (!is_vmalloc_or_module_addr((void *)p)) { |
477 | err = -ENXIO; | |
478 | break; | |
479 | } | |
80ad89a0 WF |
480 | sz = vread(kbuf, (char *)p, sz); |
481 | if (!sz) | |
1da177e4 | 482 | break; |
80ad89a0 | 483 | if (copy_to_user(buf, kbuf, sz)) { |
325fda71 KH |
484 | err = -EFAULT; |
485 | break; | |
1da177e4 | 486 | } |
80ad89a0 WF |
487 | count -= sz; |
488 | buf += sz; | |
489 | read += sz; | |
490 | p += sz; | |
1da177e4 LT |
491 | } |
492 | free_page((unsigned long)kbuf); | |
493 | } | |
325fda71 KH |
494 | *ppos = p; |
495 | return read ? read : err; | |
1da177e4 LT |
496 | } |
497 | ||
498 | ||
d7d4d849 AM |
499 | static ssize_t do_write_kmem(unsigned long p, const char __user *buf, |
500 | size_t count, loff_t *ppos) | |
1da177e4 LT |
501 | { |
502 | ssize_t written, sz; | |
503 | unsigned long copied; | |
504 | ||
505 | written = 0; | |
506 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
507 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
ee32398f WF |
508 | if (p < PAGE_SIZE) { |
509 | sz = size_inside_page(p, count); | |
1da177e4 LT |
510 | /* Hmm. Do something? */ |
511 | buf += sz; | |
512 | p += sz; | |
1da177e4 LT |
513 | count -= sz; |
514 | written += sz; | |
515 | } | |
516 | #endif | |
517 | ||
518 | while (count > 0) { | |
519 | char *ptr; | |
1da177e4 | 520 | |
ee32398f | 521 | sz = size_inside_page(p, count); |
1da177e4 LT |
522 | |
523 | /* | |
d7d4d849 AM |
524 | * On ia64 if a page has been mapped somewhere as uncached, then |
525 | * it must also be accessed uncached by the kernel or data | |
526 | * corruption may occur. | |
1da177e4 | 527 | */ |
ee32398f | 528 | ptr = xlate_dev_kmem_ptr((char *)p); |
1da177e4 LT |
529 | |
530 | copied = copy_from_user(ptr, buf, sz); | |
531 | if (copied) { | |
c654d60e JB |
532 | written += sz - copied; |
533 | if (written) | |
534 | break; | |
1da177e4 LT |
535 | return -EFAULT; |
536 | } | |
537 | buf += sz; | |
538 | p += sz; | |
1da177e4 LT |
539 | count -= sz; |
540 | written += sz; | |
541 | } | |
542 | ||
543 | *ppos += written; | |
544 | return written; | |
545 | } | |
546 | ||
1da177e4 LT |
547 | /* |
548 | * This function writes to the *virtual* memory as seen by the kernel. | |
549 | */ | |
d7d4d849 | 550 | static ssize_t write_kmem(struct file *file, const char __user *buf, |
1da177e4 LT |
551 | size_t count, loff_t *ppos) |
552 | { | |
553 | unsigned long p = *ppos; | |
554 | ssize_t wrote = 0; | |
555 | ssize_t virtr = 0; | |
890537b3 | 556 | char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ |
325fda71 | 557 | int err = 0; |
1da177e4 LT |
558 | |
559 | if (p < (unsigned long) high_memory) { | |
80ad89a0 WF |
560 | unsigned long to_write = min_t(unsigned long, count, |
561 | (unsigned long)high_memory - p); | |
ee32398f | 562 | wrote = do_write_kmem(p, buf, to_write, ppos); |
80ad89a0 WF |
563 | if (wrote != to_write) |
564 | return wrote; | |
1da177e4 LT |
565 | p += wrote; |
566 | buf += wrote; | |
567 | count -= wrote; | |
568 | } | |
569 | ||
570 | if (count > 0) { | |
571 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
572 | if (!kbuf) | |
573 | return wrote ? wrote : -ENOMEM; | |
574 | while (count > 0) { | |
80ad89a0 WF |
575 | unsigned long sz = size_inside_page(p, count); |
576 | unsigned long n; | |
1da177e4 | 577 | |
325fda71 KH |
578 | if (!is_vmalloc_or_module_addr((void *)p)) { |
579 | err = -ENXIO; | |
580 | break; | |
581 | } | |
80ad89a0 WF |
582 | n = copy_from_user(kbuf, buf, sz); |
583 | if (n) { | |
325fda71 KH |
584 | err = -EFAULT; |
585 | break; | |
1da177e4 | 586 | } |
c85e9a97 | 587 | vwrite(kbuf, (char *)p, sz); |
80ad89a0 WF |
588 | count -= sz; |
589 | buf += sz; | |
590 | virtr += sz; | |
591 | p += sz; | |
1da177e4 LT |
592 | } |
593 | free_page((unsigned long)kbuf); | |
594 | } | |
595 | ||
325fda71 KH |
596 | *ppos = p; |
597 | return virtr + wrote ? : err; | |
1da177e4 | 598 | } |
b781ecb6 | 599 | #endif |
1da177e4 | 600 | |
4f911d64 | 601 | #ifdef CONFIG_DEVPORT |
d7d4d849 | 602 | static ssize_t read_port(struct file *file, char __user *buf, |
1da177e4 LT |
603 | size_t count, loff_t *ppos) |
604 | { | |
605 | unsigned long i = *ppos; | |
606 | char __user *tmp = buf; | |
607 | ||
608 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
d7d4d849 | 609 | return -EFAULT; |
1da177e4 | 610 | while (count-- > 0 && i < 65536) { |
d7d4d849 AM |
611 | if (__put_user(inb(i), tmp) < 0) |
612 | return -EFAULT; | |
1da177e4 LT |
613 | i++; |
614 | tmp++; | |
615 | } | |
616 | *ppos = i; | |
617 | return tmp-buf; | |
618 | } | |
619 | ||
d7d4d849 | 620 | static ssize_t write_port(struct file *file, const char __user *buf, |
1da177e4 LT |
621 | size_t count, loff_t *ppos) |
622 | { | |
623 | unsigned long i = *ppos; | |
890537b3 | 624 | const char __user *tmp = buf; |
1da177e4 | 625 | |
d7d4d849 | 626 | if (!access_ok(VERIFY_READ, buf, count)) |
1da177e4 LT |
627 | return -EFAULT; |
628 | while (count-- > 0 && i < 65536) { | |
629 | char c; | |
c654d60e JB |
630 | if (__get_user(c, tmp)) { |
631 | if (tmp > buf) | |
632 | break; | |
d7d4d849 | 633 | return -EFAULT; |
c654d60e | 634 | } |
d7d4d849 | 635 | outb(c, i); |
1da177e4 LT |
636 | i++; |
637 | tmp++; | |
638 | } | |
639 | *ppos = i; | |
640 | return tmp-buf; | |
641 | } | |
642 | #endif | |
643 | ||
d7d4d849 | 644 | static ssize_t read_null(struct file *file, char __user *buf, |
1da177e4 LT |
645 | size_t count, loff_t *ppos) |
646 | { | |
647 | return 0; | |
648 | } | |
649 | ||
d7d4d849 | 650 | static ssize_t write_null(struct file *file, const char __user *buf, |
1da177e4 LT |
651 | size_t count, loff_t *ppos) |
652 | { | |
653 | return count; | |
654 | } | |
655 | ||
162934de ZB |
656 | static ssize_t aio_read_null(struct kiocb *iocb, const struct iovec *iov, |
657 | unsigned long nr_segs, loff_t pos) | |
658 | { | |
659 | return 0; | |
660 | } | |
661 | ||
662 | static ssize_t aio_write_null(struct kiocb *iocb, const struct iovec *iov, | |
663 | unsigned long nr_segs, loff_t pos) | |
664 | { | |
665 | return iov_length(iov, nr_segs); | |
666 | } | |
667 | ||
1ebd32fc JA |
668 | static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, |
669 | struct splice_desc *sd) | |
670 | { | |
671 | return sd->len; | |
672 | } | |
673 | ||
d7d4d849 | 674 | static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out, |
1ebd32fc JA |
675 | loff_t *ppos, size_t len, unsigned int flags) |
676 | { | |
677 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); | |
678 | } | |
679 | ||
d7d4d849 | 680 | static ssize_t read_zero(struct file *file, char __user *buf, |
1da177e4 LT |
681 | size_t count, loff_t *ppos) |
682 | { | |
557ed1fa | 683 | size_t written; |
1da177e4 LT |
684 | |
685 | if (!count) | |
686 | return 0; | |
687 | ||
688 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
689 | return -EFAULT; | |
690 | ||
557ed1fa NP |
691 | written = 0; |
692 | while (count) { | |
693 | unsigned long unwritten; | |
694 | size_t chunk = count; | |
1da177e4 | 695 | |
557ed1fa NP |
696 | if (chunk > PAGE_SIZE) |
697 | chunk = PAGE_SIZE; /* Just for latency reasons */ | |
bb521c5d | 698 | unwritten = __clear_user(buf, chunk); |
557ed1fa | 699 | written += chunk - unwritten; |
1da177e4 | 700 | if (unwritten) |
557ed1fa | 701 | break; |
2b838687 LT |
702 | if (signal_pending(current)) |
703 | return written ? written : -ERESTARTSYS; | |
1da177e4 | 704 | buf += chunk; |
557ed1fa | 705 | count -= chunk; |
1da177e4 LT |
706 | cond_resched(); |
707 | } | |
557ed1fa | 708 | return written ? written : -EFAULT; |
1da177e4 LT |
709 | } |
710 | ||
162934de ZB |
711 | static ssize_t aio_read_zero(struct kiocb *iocb, const struct iovec *iov, |
712 | unsigned long nr_segs, loff_t pos) | |
713 | { | |
714 | size_t written = 0; | |
715 | unsigned long i; | |
716 | ssize_t ret; | |
717 | ||
718 | for (i = 0; i < nr_segs; i++) { | |
719 | ret = read_zero(iocb->ki_filp, iov[i].iov_base, iov[i].iov_len, | |
720 | &pos); | |
721 | if (ret < 0) | |
722 | break; | |
723 | written += ret; | |
724 | } | |
725 | ||
726 | return written ? written : -EFAULT; | |
727 | } | |
728 | ||
d7d4d849 | 729 | static int mmap_zero(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 730 | { |
557ed1fa | 731 | #ifndef CONFIG_MMU |
1da177e4 | 732 | return -ENOSYS; |
557ed1fa NP |
733 | #endif |
734 | if (vma->vm_flags & VM_SHARED) | |
735 | return shmem_zero_setup(vma); | |
736 | return 0; | |
1da177e4 | 737 | } |
1da177e4 | 738 | |
d7d4d849 | 739 | static ssize_t write_full(struct file *file, const char __user *buf, |
1da177e4 LT |
740 | size_t count, loff_t *ppos) |
741 | { | |
742 | return -ENOSPC; | |
743 | } | |
744 | ||
745 | /* | |
746 | * Special lseek() function for /dev/null and /dev/zero. Most notably, you | |
747 | * can fopen() both devices with "a" now. This was previously impossible. | |
748 | * -- SRB. | |
749 | */ | |
d7d4d849 | 750 | static loff_t null_lseek(struct file *file, loff_t offset, int orig) |
1da177e4 LT |
751 | { |
752 | return file->f_pos = 0; | |
753 | } | |
754 | ||
6fa3eb70 S |
755 | #if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) || defined(CONFIG_DEVPORT) |
756 | ||
1da177e4 LT |
757 | /* |
758 | * The memory devices use the full 32/64 bits of the offset, and so we cannot | |
759 | * check against negative addresses: they are ok. The return value is weird, | |
760 | * though, in that case (0). | |
761 | * | |
762 | * also note that seeking relative to the "end of file" isn't supported: | |
763 | * it has no meaning, so it returns -EINVAL. | |
764 | */ | |
d7d4d849 | 765 | static loff_t memory_lseek(struct file *file, loff_t offset, int orig) |
1da177e4 LT |
766 | { |
767 | loff_t ret; | |
768 | ||
496ad9aa | 769 | mutex_lock(&file_inode(file)->i_mutex); |
1da177e4 | 770 | switch (orig) { |
d7d4d849 AM |
771 | case SEEK_CUR: |
772 | offset += file->f_pos; | |
d7d4d849 AM |
773 | case SEEK_SET: |
774 | /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */ | |
775 | if ((unsigned long long)offset >= ~0xFFFULL) { | |
776 | ret = -EOVERFLOW; | |
1da177e4 | 777 | break; |
d7d4d849 AM |
778 | } |
779 | file->f_pos = offset; | |
780 | ret = file->f_pos; | |
781 | force_successful_syscall_return(); | |
782 | break; | |
783 | default: | |
784 | ret = -EINVAL; | |
1da177e4 | 785 | } |
496ad9aa | 786 | mutex_unlock(&file_inode(file)->i_mutex); |
1da177e4 LT |
787 | return ret; |
788 | } | |
789 | ||
6fa3eb70 S |
790 | #endif |
791 | ||
792 | #if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) || defined(CONFIG_DEVPORT) | |
890537b3 | 793 | static int open_port(struct inode *inode, struct file *filp) |
1da177e4 LT |
794 | { |
795 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; | |
796 | } | |
6fa3eb70 | 797 | #endif |
1da177e4 LT |
798 | |
799 | #define zero_lseek null_lseek | |
800 | #define full_lseek null_lseek | |
801 | #define write_zero write_null | |
802 | #define read_full read_zero | |
162934de | 803 | #define aio_write_zero aio_write_null |
1da177e4 LT |
804 | #define open_mem open_port |
805 | #define open_kmem open_mem | |
50b1fdbd | 806 | #define open_oldmem open_mem |
1da177e4 | 807 | |
6fa3eb70 | 808 | #ifdef CONFIG_DEVMEM |
62322d25 | 809 | static const struct file_operations mem_fops = { |
1da177e4 LT |
810 | .llseek = memory_lseek, |
811 | .read = read_mem, | |
812 | .write = write_mem, | |
813 | .mmap = mmap_mem, | |
814 | .open = open_mem, | |
5da6185b | 815 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 | 816 | }; |
6fa3eb70 | 817 | #endif |
1da177e4 | 818 | |
b781ecb6 | 819 | #ifdef CONFIG_DEVKMEM |
62322d25 | 820 | static const struct file_operations kmem_fops = { |
1da177e4 LT |
821 | .llseek = memory_lseek, |
822 | .read = read_kmem, | |
823 | .write = write_kmem, | |
824 | .mmap = mmap_kmem, | |
825 | .open = open_kmem, | |
5da6185b | 826 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 | 827 | }; |
b781ecb6 | 828 | #endif |
1da177e4 | 829 | |
62322d25 | 830 | static const struct file_operations null_fops = { |
1da177e4 LT |
831 | .llseek = null_lseek, |
832 | .read = read_null, | |
833 | .write = write_null, | |
162934de ZB |
834 | .aio_read = aio_read_null, |
835 | .aio_write = aio_write_null, | |
1ebd32fc | 836 | .splice_write = splice_write_null, |
1da177e4 LT |
837 | }; |
838 | ||
4f911d64 | 839 | #ifdef CONFIG_DEVPORT |
62322d25 | 840 | static const struct file_operations port_fops = { |
1da177e4 LT |
841 | .llseek = memory_lseek, |
842 | .read = read_port, | |
843 | .write = write_port, | |
844 | .open = open_port, | |
845 | }; | |
846 | #endif | |
847 | ||
62322d25 | 848 | static const struct file_operations zero_fops = { |
1da177e4 LT |
849 | .llseek = zero_lseek, |
850 | .read = read_zero, | |
851 | .write = write_zero, | |
162934de ZB |
852 | .aio_read = aio_read_zero, |
853 | .aio_write = aio_write_zero, | |
1da177e4 LT |
854 | .mmap = mmap_zero, |
855 | }; | |
856 | ||
5da6185b DH |
857 | /* |
858 | * capabilities for /dev/zero | |
859 | * - permits private mappings, "copies" are taken of the source of zeros | |
371d217e | 860 | * - no writeback happens |
5da6185b | 861 | */ |
1da177e4 | 862 | static struct backing_dev_info zero_bdi = { |
d993831f | 863 | .name = "char/mem", |
371d217e | 864 | .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK, |
1da177e4 LT |
865 | }; |
866 | ||
62322d25 | 867 | static const struct file_operations full_fops = { |
1da177e4 LT |
868 | .llseek = full_lseek, |
869 | .read = read_full, | |
870 | .write = write_full, | |
871 | }; | |
872 | ||
50b1fdbd | 873 | #ifdef CONFIG_CRASH_DUMP |
62322d25 | 874 | static const struct file_operations oldmem_fops = { |
50b1fdbd VG |
875 | .read = read_oldmem, |
876 | .open = open_oldmem, | |
6038f373 | 877 | .llseek = default_llseek, |
50b1fdbd VG |
878 | }; |
879 | #endif | |
880 | ||
389e0cb9 KS |
881 | static const struct memdev { |
882 | const char *name; | |
2c9ede55 | 883 | umode_t mode; |
389e0cb9 KS |
884 | const struct file_operations *fops; |
885 | struct backing_dev_info *dev_info; | |
886 | } devlist[] = { | |
6fa3eb70 | 887 | #ifdef CONFIG_DEVMEM |
e454cea2 | 888 | [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi }, |
6fa3eb70 | 889 | #endif |
b781ecb6 | 890 | #ifdef CONFIG_DEVKMEM |
e454cea2 | 891 | [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi }, |
b781ecb6 | 892 | #endif |
e454cea2 | 893 | [3] = { "null", 0666, &null_fops, NULL }, |
4f911d64 | 894 | #ifdef CONFIG_DEVPORT |
e454cea2 | 895 | [4] = { "port", 0, &port_fops, NULL }, |
1da177e4 | 896 | #endif |
e454cea2 KS |
897 | [5] = { "zero", 0666, &zero_fops, &zero_bdi }, |
898 | [7] = { "full", 0666, &full_fops, NULL }, | |
899 | [8] = { "random", 0666, &random_fops, NULL }, | |
900 | [9] = { "urandom", 0666, &urandom_fops, NULL }, | |
7f3a781d | 901 | #ifdef CONFIG_PRINTK |
e11fea92 | 902 | [11] = { "kmsg", 0644, &kmsg_fops, NULL }, |
7f3a781d | 903 | #endif |
50b1fdbd | 904 | #ifdef CONFIG_CRASH_DUMP |
e454cea2 | 905 | [12] = { "oldmem", 0, &oldmem_fops, NULL }, |
50b1fdbd | 906 | #endif |
d6f47bef ASF |
907 | }; |
908 | ||
909 | static int memory_open(struct inode *inode, struct file *filp) | |
910 | { | |
389e0cb9 KS |
911 | int minor; |
912 | const struct memdev *dev; | |
d6f47bef | 913 | |
389e0cb9 KS |
914 | minor = iminor(inode); |
915 | if (minor >= ARRAY_SIZE(devlist)) | |
205153aa | 916 | return -ENXIO; |
d6f47bef | 917 | |
389e0cb9 KS |
918 | dev = &devlist[minor]; |
919 | if (!dev->fops) | |
205153aa | 920 | return -ENXIO; |
d6f47bef | 921 | |
389e0cb9 KS |
922 | filp->f_op = dev->fops; |
923 | if (dev->dev_info) | |
924 | filp->f_mapping->backing_dev_info = dev->dev_info; | |
d6f47bef | 925 | |
4a3956c7 KH |
926 | /* Is /dev/mem or /dev/kmem ? */ |
927 | if (dev->dev_info == &directly_mappable_cdev_bdi) | |
928 | filp->f_mode |= FMODE_UNSIGNED_OFFSET; | |
929 | ||
389e0cb9 | 930 | if (dev->fops->open) |
205153aa FW |
931 | return dev->fops->open(inode, filp); |
932 | ||
933 | return 0; | |
1da177e4 LT |
934 | } |
935 | ||
62322d25 | 936 | static const struct file_operations memory_fops = { |
d7d4d849 | 937 | .open = memory_open, |
6038f373 | 938 | .llseek = noop_llseek, |
1da177e4 LT |
939 | }; |
940 | ||
2c9ede55 | 941 | static char *mem_devnode(struct device *dev, umode_t *mode) |
e454cea2 KS |
942 | { |
943 | if (mode && devlist[MINOR(dev->devt)].mode) | |
944 | *mode = devlist[MINOR(dev->devt)].mode; | |
945 | return NULL; | |
946 | } | |
947 | ||
ca8eca68 | 948 | static struct class *mem_class; |
1da177e4 LT |
949 | |
950 | static int __init chr_dev_init(void) | |
951 | { | |
389e0cb9 | 952 | int minor; |
e0bf68dd PZ |
953 | int err; |
954 | ||
955 | err = bdi_init(&zero_bdi); | |
956 | if (err) | |
957 | return err; | |
1da177e4 | 958 | |
d7d4d849 | 959 | if (register_chrdev(MEM_MAJOR, "mem", &memory_fops)) |
1da177e4 LT |
960 | printk("unable to get major %d for memory devs\n", MEM_MAJOR); |
961 | ||
ca8eca68 | 962 | mem_class = class_create(THIS_MODULE, "mem"); |
6e191f7b AB |
963 | if (IS_ERR(mem_class)) |
964 | return PTR_ERR(mem_class); | |
965 | ||
e454cea2 | 966 | mem_class->devnode = mem_devnode; |
389e0cb9 KS |
967 | for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) { |
968 | if (!devlist[minor].name) | |
969 | continue; | |
e1612de9 HM |
970 | |
971 | /* | |
890537b3 | 972 | * Create /dev/port? |
e1612de9 HM |
973 | */ |
974 | if ((minor == DEVPORT_MINOR) && !arch_has_dev_port()) | |
975 | continue; | |
976 | ||
389e0cb9 KS |
977 | device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor), |
978 | NULL, devlist[minor].name); | |
979 | } | |
ebf644c4 | 980 | |
31d1d48e | 981 | return tty_init(); |
1da177e4 LT |
982 | } |
983 | ||
984 | fs_initcall(chr_dev_init); |