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 | 23 | #include <linux/highmem.h> |
1da177e4 | 24 | #include <linux/backing-dev.h> |
d6b29d7c | 25 | #include <linux/splice.h> |
b8a3ad5b | 26 | #include <linux/pfn.h> |
66300e66 | 27 | #include <linux/export.h> |
e1612de9 | 28 | #include <linux/io.h> |
a27bb332 | 29 | #include <linux/aio.h> |
1da177e4 LT |
30 | |
31 | #include <asm/uaccess.h> | |
1da177e4 LT |
32 | |
33 | #ifdef CONFIG_IA64 | |
34 | # include <linux/efi.h> | |
35 | #endif | |
36 | ||
e1612de9 HM |
37 | #define DEVPORT_MINOR 4 |
38 | ||
f222318e WF |
39 | static inline unsigned long size_inside_page(unsigned long start, |
40 | unsigned long size) | |
41 | { | |
42 | unsigned long sz; | |
43 | ||
7fabaddd | 44 | sz = PAGE_SIZE - (start & (PAGE_SIZE - 1)); |
f222318e | 45 | |
7fabaddd | 46 | return min(sz, size); |
f222318e WF |
47 | } |
48 | ||
1da177e4 | 49 | #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE |
7e6735c3 | 50 | static inline int valid_phys_addr_range(phys_addr_t addr, size_t count) |
1da177e4 | 51 | { |
cfaf346c | 52 | return addr + count <= __pa(high_memory); |
1da177e4 | 53 | } |
80851ef2 | 54 | |
06c67bef | 55 | static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) |
80851ef2 BH |
56 | { |
57 | return 1; | |
58 | } | |
1da177e4 LT |
59 | #endif |
60 | ||
d092633b | 61 | #ifdef CONFIG_STRICT_DEVMEM |
e2beb3ea | 62 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 | 63 | { |
e2beb3ea VP |
64 | u64 from = ((u64)pfn) << PAGE_SHIFT; |
65 | u64 to = from + size; | |
66 | u64 cursor = from; | |
67 | ||
68 | while (cursor < to) { | |
69 | if (!devmem_is_allowed(pfn)) { | |
70 | printk(KERN_INFO | |
71 | "Program %s tried to access /dev/mem between %Lx->%Lx.\n", | |
ae531c26 AV |
72 | current->comm, from, to); |
73 | return 0; | |
74 | } | |
e2beb3ea VP |
75 | cursor += PAGE_SIZE; |
76 | pfn++; | |
ae531c26 AV |
77 | } |
78 | return 1; | |
79 | } | |
80 | #else | |
e2beb3ea | 81 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 AV |
82 | { |
83 | return 1; | |
84 | } | |
85 | #endif | |
86 | ||
d7d4d849 | 87 | void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr) |
e045fb2a | 88 | { |
89 | } | |
90 | ||
1da177e4 | 91 | /* |
d7d4d849 AM |
92 | * This funcion reads the *physical* memory. The f_pos points directly to the |
93 | * memory location. | |
1da177e4 | 94 | */ |
d7d4d849 | 95 | static ssize_t read_mem(struct file *file, char __user *buf, |
1da177e4 LT |
96 | size_t count, loff_t *ppos) |
97 | { | |
7e6735c3 | 98 | phys_addr_t p = *ppos; |
1da177e4 LT |
99 | ssize_t read, sz; |
100 | char *ptr; | |
101 | ||
136939a2 | 102 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
103 | return -EFAULT; |
104 | read = 0; | |
105 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
106 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
107 | if (p < PAGE_SIZE) { | |
7fabaddd | 108 | sz = size_inside_page(p, count); |
1da177e4 LT |
109 | if (sz > 0) { |
110 | if (clear_user(buf, sz)) | |
111 | return -EFAULT; | |
d7d4d849 AM |
112 | buf += sz; |
113 | p += sz; | |
114 | count -= sz; | |
115 | read += sz; | |
1da177e4 LT |
116 | } |
117 | } | |
118 | #endif | |
119 | ||
120 | while (count > 0) { | |
fa29e97b WF |
121 | unsigned long remaining; |
122 | ||
f222318e | 123 | sz = size_inside_page(p, count); |
1da177e4 | 124 | |
e045fb2a | 125 | if (!range_is_allowed(p >> PAGE_SHIFT, count)) |
126 | return -EPERM; | |
127 | ||
1da177e4 | 128 | /* |
d7d4d849 AM |
129 | * On ia64 if a page has been mapped somewhere as uncached, then |
130 | * it must also be accessed uncached by the kernel or data | |
131 | * corruption may occur. | |
1da177e4 LT |
132 | */ |
133 | ptr = xlate_dev_mem_ptr(p); | |
e045fb2a | 134 | if (!ptr) |
135 | return -EFAULT; | |
1da177e4 | 136 | |
fa29e97b | 137 | remaining = copy_to_user(buf, ptr, sz); |
e045fb2a | 138 | unxlate_dev_mem_ptr(p, ptr); |
fa29e97b WF |
139 | if (remaining) |
140 | return -EFAULT; | |
e045fb2a | 141 | |
1da177e4 LT |
142 | buf += sz; |
143 | p += sz; | |
144 | count -= sz; | |
145 | read += sz; | |
146 | } | |
147 | ||
148 | *ppos += read; | |
149 | return read; | |
150 | } | |
151 | ||
d7d4d849 | 152 | static ssize_t write_mem(struct file *file, const char __user *buf, |
1da177e4 LT |
153 | size_t count, loff_t *ppos) |
154 | { | |
7e6735c3 | 155 | phys_addr_t p = *ppos; |
1da177e4 LT |
156 | ssize_t written, sz; |
157 | unsigned long copied; | |
158 | void *ptr; | |
159 | ||
136939a2 | 160 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
161 | return -EFAULT; |
162 | ||
163 | written = 0; | |
164 | ||
165 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
166 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
167 | if (p < PAGE_SIZE) { | |
7fabaddd | 168 | sz = size_inside_page(p, count); |
1da177e4 LT |
169 | /* Hmm. Do something? */ |
170 | buf += sz; | |
171 | p += sz; | |
172 | count -= sz; | |
173 | written += sz; | |
174 | } | |
175 | #endif | |
176 | ||
177 | while (count > 0) { | |
f222318e | 178 | sz = size_inside_page(p, count); |
1da177e4 | 179 | |
e045fb2a | 180 | if (!range_is_allowed(p >> PAGE_SHIFT, sz)) |
181 | return -EPERM; | |
182 | ||
1da177e4 | 183 | /* |
d7d4d849 AM |
184 | * On ia64 if a page has been mapped somewhere as uncached, then |
185 | * it must also be accessed uncached by the kernel or data | |
186 | * corruption may occur. | |
1da177e4 LT |
187 | */ |
188 | ptr = xlate_dev_mem_ptr(p); | |
e045fb2a | 189 | if (!ptr) { |
190 | if (written) | |
191 | break; | |
192 | return -EFAULT; | |
193 | } | |
1da177e4 LT |
194 | |
195 | copied = copy_from_user(ptr, buf, sz); | |
fa29e97b | 196 | unxlate_dev_mem_ptr(p, ptr); |
1da177e4 | 197 | if (copied) { |
c654d60e JB |
198 | written += sz - copied; |
199 | if (written) | |
200 | break; | |
1da177e4 LT |
201 | return -EFAULT; |
202 | } | |
e045fb2a | 203 | |
1da177e4 LT |
204 | buf += sz; |
205 | p += sz; | |
206 | count -= sz; | |
207 | written += sz; | |
208 | } | |
209 | ||
210 | *ppos += written; | |
211 | return written; | |
212 | } | |
213 | ||
d7d4d849 | 214 | int __weak phys_mem_access_prot_allowed(struct file *file, |
f0970c13 | 215 | unsigned long pfn, unsigned long size, pgprot_t *vma_prot) |
216 | { | |
217 | return 1; | |
218 | } | |
219 | ||
44ac8413 | 220 | #ifndef __HAVE_PHYS_MEM_ACCESS_PROT |
d7d4d849 AM |
221 | |
222 | /* | |
223 | * Architectures vary in how they handle caching for addresses | |
224 | * outside of main memory. | |
225 | * | |
226 | */ | |
ea56f411 | 227 | #ifdef pgprot_noncached |
7e6735c3 | 228 | static int uncached_access(struct file *file, phys_addr_t addr) |
d7d4d849 AM |
229 | { |
230 | #if defined(CONFIG_IA64) | |
231 | /* | |
232 | * On ia64, we ignore O_DSYNC because we cannot tolerate memory | |
233 | * attribute aliases. | |
234 | */ | |
235 | return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); | |
236 | #elif defined(CONFIG_MIPS) | |
237 | { | |
238 | extern int __uncached_access(struct file *file, | |
239 | unsigned long addr); | |
240 | ||
241 | return __uncached_access(file, addr); | |
242 | } | |
243 | #else | |
244 | /* | |
245 | * Accessing memory above the top the kernel knows about or through a | |
246 | * file pointer | |
247 | * that was marked O_DSYNC will be done non-cached. | |
248 | */ | |
249 | if (file->f_flags & O_DSYNC) | |
250 | return 1; | |
251 | return addr >= __pa(high_memory); | |
252 | #endif | |
253 | } | |
ea56f411 | 254 | #endif |
d7d4d849 | 255 | |
44ac8413 BH |
256 | static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, |
257 | unsigned long size, pgprot_t vma_prot) | |
258 | { | |
259 | #ifdef pgprot_noncached | |
7e6735c3 | 260 | phys_addr_t offset = pfn << PAGE_SHIFT; |
44ac8413 BH |
261 | |
262 | if (uncached_access(file, offset)) | |
263 | return pgprot_noncached(vma_prot); | |
264 | #endif | |
265 | return vma_prot; | |
266 | } | |
267 | #endif | |
268 | ||
5da6185b DH |
269 | #ifndef CONFIG_MMU |
270 | static unsigned long get_unmapped_area_mem(struct file *file, | |
271 | unsigned long addr, | |
272 | unsigned long len, | |
273 | unsigned long pgoff, | |
274 | unsigned long flags) | |
275 | { | |
276 | if (!valid_mmap_phys_addr_range(pgoff, len)) | |
277 | return (unsigned long) -EINVAL; | |
8a93258c | 278 | return pgoff << PAGE_SHIFT; |
5da6185b DH |
279 | } |
280 | ||
281 | /* can't do an in-place private mapping if there's no MMU */ | |
282 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
283 | { | |
284 | return vma->vm_flags & VM_MAYSHARE; | |
285 | } | |
286 | #else | |
287 | #define get_unmapped_area_mem NULL | |
288 | ||
289 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
290 | { | |
291 | return 1; | |
292 | } | |
293 | #endif | |
294 | ||
f0f37e2f | 295 | static const struct vm_operations_struct mmap_mem_ops = { |
7ae8ed50 RR |
296 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
297 | .access = generic_access_phys | |
298 | #endif | |
e7f260a2 | 299 | }; |
300 | ||
d7d4d849 | 301 | static int mmap_mem(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 302 | { |
80851ef2 BH |
303 | size_t size = vma->vm_end - vma->vm_start; |
304 | ||
06c67bef | 305 | if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) |
80851ef2 BH |
306 | return -EINVAL; |
307 | ||
5da6185b DH |
308 | if (!private_mapping_ok(vma)) |
309 | return -ENOSYS; | |
310 | ||
e2beb3ea VP |
311 | if (!range_is_allowed(vma->vm_pgoff, size)) |
312 | return -EPERM; | |
313 | ||
f0970c13 | 314 | if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, |
315 | &vma->vm_page_prot)) | |
316 | return -EINVAL; | |
317 | ||
8b150478 | 318 | vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, |
80851ef2 | 319 | size, |
1da177e4 | 320 | vma->vm_page_prot); |
1da177e4 | 321 | |
e7f260a2 | 322 | vma->vm_ops = &mmap_mem_ops; |
323 | ||
314e51b9 | 324 | /* Remap-pfn-range will mark the range VM_IO */ |
1da177e4 LT |
325 | if (remap_pfn_range(vma, |
326 | vma->vm_start, | |
327 | vma->vm_pgoff, | |
80851ef2 | 328 | size, |
e7f260a2 | 329 | vma->vm_page_prot)) { |
1da177e4 | 330 | return -EAGAIN; |
e7f260a2 | 331 | } |
1da177e4 LT |
332 | return 0; |
333 | } | |
334 | ||
b781ecb6 | 335 | #ifdef CONFIG_DEVKMEM |
d7d4d849 | 336 | static int mmap_kmem(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 337 | { |
4bb82551 LT |
338 | unsigned long pfn; |
339 | ||
6d3154cc LT |
340 | /* Turn a kernel-virtual address into a physical page frame */ |
341 | pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; | |
4bb82551 | 342 | |
1da177e4 | 343 | /* |
d7d4d849 AM |
344 | * RED-PEN: on some architectures there is more mapped memory than |
345 | * available in mem_map which pfn_valid checks for. Perhaps should add a | |
346 | * new macro here. | |
1da177e4 LT |
347 | * |
348 | * RED-PEN: vmalloc is not supported right now. | |
349 | */ | |
4bb82551 | 350 | if (!pfn_valid(pfn)) |
1da177e4 | 351 | return -EIO; |
4bb82551 LT |
352 | |
353 | vma->vm_pgoff = pfn; | |
1da177e4 LT |
354 | return mmap_mem(file, vma); |
355 | } | |
b781ecb6 | 356 | #endif |
1da177e4 | 357 | |
b781ecb6 | 358 | #ifdef CONFIG_DEVKMEM |
1da177e4 LT |
359 | /* |
360 | * This function reads the *virtual* memory as seen by the kernel. | |
361 | */ | |
d7d4d849 | 362 | static ssize_t read_kmem(struct file *file, char __user *buf, |
1da177e4 LT |
363 | size_t count, loff_t *ppos) |
364 | { | |
365 | unsigned long p = *ppos; | |
366 | ssize_t low_count, read, sz; | |
890537b3 | 367 | char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ |
325fda71 | 368 | int err = 0; |
1da177e4 LT |
369 | |
370 | read = 0; | |
371 | if (p < (unsigned long) high_memory) { | |
372 | low_count = count; | |
d7d4d849 AM |
373 | if (count > (unsigned long)high_memory - p) |
374 | low_count = (unsigned long)high_memory - p; | |
1da177e4 LT |
375 | |
376 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
377 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
378 | if (p < PAGE_SIZE && low_count > 0) { | |
7fabaddd WF |
379 | sz = size_inside_page(p, low_count); |
380 | if (clear_user(buf, sz)) | |
1da177e4 | 381 | return -EFAULT; |
7fabaddd WF |
382 | buf += sz; |
383 | p += sz; | |
384 | read += sz; | |
385 | low_count -= sz; | |
386 | count -= sz; | |
1da177e4 LT |
387 | } |
388 | #endif | |
389 | while (low_count > 0) { | |
f222318e | 390 | sz = size_inside_page(p, low_count); |
1da177e4 LT |
391 | |
392 | /* | |
393 | * On ia64 if a page has been mapped somewhere as | |
394 | * uncached, then it must also be accessed uncached | |
395 | * by the kernel or data corruption may occur | |
396 | */ | |
397 | kbuf = xlate_dev_kmem_ptr((char *)p); | |
398 | ||
399 | if (copy_to_user(buf, kbuf, sz)) | |
400 | return -EFAULT; | |
401 | buf += sz; | |
402 | p += sz; | |
403 | read += sz; | |
404 | low_count -= sz; | |
405 | count -= sz; | |
406 | } | |
407 | } | |
408 | ||
409 | if (count > 0) { | |
410 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
411 | if (!kbuf) | |
412 | return -ENOMEM; | |
413 | while (count > 0) { | |
80ad89a0 | 414 | sz = size_inside_page(p, count); |
325fda71 KH |
415 | if (!is_vmalloc_or_module_addr((void *)p)) { |
416 | err = -ENXIO; | |
417 | break; | |
418 | } | |
80ad89a0 WF |
419 | sz = vread(kbuf, (char *)p, sz); |
420 | if (!sz) | |
1da177e4 | 421 | break; |
80ad89a0 | 422 | if (copy_to_user(buf, kbuf, sz)) { |
325fda71 KH |
423 | err = -EFAULT; |
424 | break; | |
1da177e4 | 425 | } |
80ad89a0 WF |
426 | count -= sz; |
427 | buf += sz; | |
428 | read += sz; | |
429 | p += sz; | |
1da177e4 LT |
430 | } |
431 | free_page((unsigned long)kbuf); | |
432 | } | |
325fda71 KH |
433 | *ppos = p; |
434 | return read ? read : err; | |
1da177e4 LT |
435 | } |
436 | ||
437 | ||
d7d4d849 AM |
438 | static ssize_t do_write_kmem(unsigned long p, const char __user *buf, |
439 | size_t count, loff_t *ppos) | |
1da177e4 LT |
440 | { |
441 | ssize_t written, sz; | |
442 | unsigned long copied; | |
443 | ||
444 | written = 0; | |
445 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
446 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
ee32398f WF |
447 | if (p < PAGE_SIZE) { |
448 | sz = size_inside_page(p, count); | |
1da177e4 LT |
449 | /* Hmm. Do something? */ |
450 | buf += sz; | |
451 | p += sz; | |
1da177e4 LT |
452 | count -= sz; |
453 | written += sz; | |
454 | } | |
455 | #endif | |
456 | ||
457 | while (count > 0) { | |
458 | char *ptr; | |
1da177e4 | 459 | |
ee32398f | 460 | sz = size_inside_page(p, count); |
1da177e4 LT |
461 | |
462 | /* | |
d7d4d849 AM |
463 | * On ia64 if a page has been mapped somewhere as uncached, then |
464 | * it must also be accessed uncached by the kernel or data | |
465 | * corruption may occur. | |
1da177e4 | 466 | */ |
ee32398f | 467 | ptr = xlate_dev_kmem_ptr((char *)p); |
1da177e4 LT |
468 | |
469 | copied = copy_from_user(ptr, buf, sz); | |
470 | if (copied) { | |
c654d60e JB |
471 | written += sz - copied; |
472 | if (written) | |
473 | break; | |
1da177e4 LT |
474 | return -EFAULT; |
475 | } | |
476 | buf += sz; | |
477 | p += sz; | |
1da177e4 LT |
478 | count -= sz; |
479 | written += sz; | |
480 | } | |
481 | ||
482 | *ppos += written; | |
483 | return written; | |
484 | } | |
485 | ||
1da177e4 LT |
486 | /* |
487 | * This function writes to the *virtual* memory as seen by the kernel. | |
488 | */ | |
d7d4d849 | 489 | static ssize_t write_kmem(struct file *file, const char __user *buf, |
1da177e4 LT |
490 | size_t count, loff_t *ppos) |
491 | { | |
492 | unsigned long p = *ppos; | |
493 | ssize_t wrote = 0; | |
494 | ssize_t virtr = 0; | |
890537b3 | 495 | char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ |
325fda71 | 496 | int err = 0; |
1da177e4 LT |
497 | |
498 | if (p < (unsigned long) high_memory) { | |
80ad89a0 WF |
499 | unsigned long to_write = min_t(unsigned long, count, |
500 | (unsigned long)high_memory - p); | |
ee32398f | 501 | wrote = do_write_kmem(p, buf, to_write, ppos); |
80ad89a0 WF |
502 | if (wrote != to_write) |
503 | return wrote; | |
1da177e4 LT |
504 | p += wrote; |
505 | buf += wrote; | |
506 | count -= wrote; | |
507 | } | |
508 | ||
509 | if (count > 0) { | |
510 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
511 | if (!kbuf) | |
512 | return wrote ? wrote : -ENOMEM; | |
513 | while (count > 0) { | |
80ad89a0 WF |
514 | unsigned long sz = size_inside_page(p, count); |
515 | unsigned long n; | |
1da177e4 | 516 | |
325fda71 KH |
517 | if (!is_vmalloc_or_module_addr((void *)p)) { |
518 | err = -ENXIO; | |
519 | break; | |
520 | } | |
80ad89a0 WF |
521 | n = copy_from_user(kbuf, buf, sz); |
522 | if (n) { | |
325fda71 KH |
523 | err = -EFAULT; |
524 | break; | |
1da177e4 | 525 | } |
c85e9a97 | 526 | vwrite(kbuf, (char *)p, sz); |
80ad89a0 WF |
527 | count -= sz; |
528 | buf += sz; | |
529 | virtr += sz; | |
530 | p += sz; | |
1da177e4 LT |
531 | } |
532 | free_page((unsigned long)kbuf); | |
533 | } | |
534 | ||
325fda71 KH |
535 | *ppos = p; |
536 | return virtr + wrote ? : err; | |
1da177e4 | 537 | } |
b781ecb6 | 538 | #endif |
1da177e4 | 539 | |
4f911d64 | 540 | #ifdef CONFIG_DEVPORT |
d7d4d849 | 541 | static ssize_t read_port(struct file *file, char __user *buf, |
1da177e4 LT |
542 | size_t count, loff_t *ppos) |
543 | { | |
544 | unsigned long i = *ppos; | |
545 | char __user *tmp = buf; | |
546 | ||
547 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
d7d4d849 | 548 | return -EFAULT; |
1da177e4 | 549 | while (count-- > 0 && i < 65536) { |
d7d4d849 AM |
550 | if (__put_user(inb(i), tmp) < 0) |
551 | return -EFAULT; | |
1da177e4 LT |
552 | i++; |
553 | tmp++; | |
554 | } | |
555 | *ppos = i; | |
556 | return tmp-buf; | |
557 | } | |
558 | ||
d7d4d849 | 559 | static ssize_t write_port(struct file *file, const char __user *buf, |
1da177e4 LT |
560 | size_t count, loff_t *ppos) |
561 | { | |
562 | unsigned long i = *ppos; | |
890537b3 | 563 | const char __user *tmp = buf; |
1da177e4 | 564 | |
d7d4d849 | 565 | if (!access_ok(VERIFY_READ, buf, count)) |
1da177e4 LT |
566 | return -EFAULT; |
567 | while (count-- > 0 && i < 65536) { | |
568 | char c; | |
c654d60e JB |
569 | if (__get_user(c, tmp)) { |
570 | if (tmp > buf) | |
571 | break; | |
d7d4d849 | 572 | return -EFAULT; |
c654d60e | 573 | } |
d7d4d849 | 574 | outb(c, i); |
1da177e4 LT |
575 | i++; |
576 | tmp++; | |
577 | } | |
578 | *ppos = i; | |
579 | return tmp-buf; | |
580 | } | |
581 | #endif | |
582 | ||
d7d4d849 | 583 | static ssize_t read_null(struct file *file, char __user *buf, |
1da177e4 LT |
584 | size_t count, loff_t *ppos) |
585 | { | |
586 | return 0; | |
587 | } | |
588 | ||
d7d4d849 | 589 | static ssize_t write_null(struct file *file, const char __user *buf, |
1da177e4 LT |
590 | size_t count, loff_t *ppos) |
591 | { | |
592 | return count; | |
593 | } | |
594 | ||
162934de ZB |
595 | static ssize_t aio_read_null(struct kiocb *iocb, const struct iovec *iov, |
596 | unsigned long nr_segs, loff_t pos) | |
597 | { | |
598 | return 0; | |
599 | } | |
600 | ||
601 | static ssize_t aio_write_null(struct kiocb *iocb, const struct iovec *iov, | |
602 | unsigned long nr_segs, loff_t pos) | |
603 | { | |
604 | return iov_length(iov, nr_segs); | |
605 | } | |
606 | ||
1ebd32fc JA |
607 | static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, |
608 | struct splice_desc *sd) | |
609 | { | |
610 | return sd->len; | |
611 | } | |
612 | ||
d7d4d849 | 613 | static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out, |
1ebd32fc JA |
614 | loff_t *ppos, size_t len, unsigned int flags) |
615 | { | |
616 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); | |
617 | } | |
618 | ||
d7d4d849 | 619 | static ssize_t read_zero(struct file *file, char __user *buf, |
1da177e4 LT |
620 | size_t count, loff_t *ppos) |
621 | { | |
557ed1fa | 622 | size_t written; |
1da177e4 LT |
623 | |
624 | if (!count) | |
625 | return 0; | |
626 | ||
627 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
628 | return -EFAULT; | |
629 | ||
557ed1fa NP |
630 | written = 0; |
631 | while (count) { | |
632 | unsigned long unwritten; | |
633 | size_t chunk = count; | |
1da177e4 | 634 | |
557ed1fa NP |
635 | if (chunk > PAGE_SIZE) |
636 | chunk = PAGE_SIZE; /* Just for latency reasons */ | |
bb521c5d | 637 | unwritten = __clear_user(buf, chunk); |
557ed1fa | 638 | written += chunk - unwritten; |
1da177e4 | 639 | if (unwritten) |
557ed1fa | 640 | break; |
2b838687 LT |
641 | if (signal_pending(current)) |
642 | return written ? written : -ERESTARTSYS; | |
1da177e4 | 643 | buf += chunk; |
557ed1fa | 644 | count -= chunk; |
1da177e4 LT |
645 | cond_resched(); |
646 | } | |
557ed1fa | 647 | return written ? written : -EFAULT; |
1da177e4 LT |
648 | } |
649 | ||
162934de ZB |
650 | static ssize_t aio_read_zero(struct kiocb *iocb, const struct iovec *iov, |
651 | unsigned long nr_segs, loff_t pos) | |
652 | { | |
653 | size_t written = 0; | |
654 | unsigned long i; | |
655 | ssize_t ret; | |
656 | ||
657 | for (i = 0; i < nr_segs; i++) { | |
658 | ret = read_zero(iocb->ki_filp, iov[i].iov_base, iov[i].iov_len, | |
659 | &pos); | |
660 | if (ret < 0) | |
661 | break; | |
662 | written += ret; | |
663 | } | |
664 | ||
665 | return written ? written : -EFAULT; | |
666 | } | |
667 | ||
d7d4d849 | 668 | static int mmap_zero(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 669 | { |
557ed1fa | 670 | #ifndef CONFIG_MMU |
1da177e4 | 671 | return -ENOSYS; |
557ed1fa NP |
672 | #endif |
673 | if (vma->vm_flags & VM_SHARED) | |
674 | return shmem_zero_setup(vma); | |
675 | return 0; | |
1da177e4 | 676 | } |
1da177e4 | 677 | |
d7d4d849 | 678 | static ssize_t write_full(struct file *file, const char __user *buf, |
1da177e4 LT |
679 | size_t count, loff_t *ppos) |
680 | { | |
681 | return -ENOSPC; | |
682 | } | |
683 | ||
684 | /* | |
685 | * Special lseek() function for /dev/null and /dev/zero. Most notably, you | |
686 | * can fopen() both devices with "a" now. This was previously impossible. | |
687 | * -- SRB. | |
688 | */ | |
d7d4d849 | 689 | static loff_t null_lseek(struct file *file, loff_t offset, int orig) |
1da177e4 LT |
690 | { |
691 | return file->f_pos = 0; | |
692 | } | |
693 | ||
694 | /* | |
695 | * The memory devices use the full 32/64 bits of the offset, and so we cannot | |
696 | * check against negative addresses: they are ok. The return value is weird, | |
697 | * though, in that case (0). | |
698 | * | |
699 | * also note that seeking relative to the "end of file" isn't supported: | |
700 | * it has no meaning, so it returns -EINVAL. | |
701 | */ | |
d7d4d849 | 702 | static loff_t memory_lseek(struct file *file, loff_t offset, int orig) |
1da177e4 LT |
703 | { |
704 | loff_t ret; | |
705 | ||
496ad9aa | 706 | mutex_lock(&file_inode(file)->i_mutex); |
1da177e4 | 707 | switch (orig) { |
d7d4d849 AM |
708 | case SEEK_CUR: |
709 | offset += file->f_pos; | |
d7d4d849 AM |
710 | case SEEK_SET: |
711 | /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */ | |
71811f32 | 712 | if (IS_ERR_VALUE((unsigned long long)offset)) { |
d7d4d849 | 713 | ret = -EOVERFLOW; |
1da177e4 | 714 | break; |
d7d4d849 AM |
715 | } |
716 | file->f_pos = offset; | |
717 | ret = file->f_pos; | |
718 | force_successful_syscall_return(); | |
719 | break; | |
720 | default: | |
721 | ret = -EINVAL; | |
1da177e4 | 722 | } |
496ad9aa | 723 | mutex_unlock(&file_inode(file)->i_mutex); |
1da177e4 LT |
724 | return ret; |
725 | } | |
726 | ||
890537b3 | 727 | static int open_port(struct inode *inode, struct file *filp) |
1da177e4 LT |
728 | { |
729 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; | |
730 | } | |
731 | ||
732 | #define zero_lseek null_lseek | |
733 | #define full_lseek null_lseek | |
734 | #define write_zero write_null | |
735 | #define read_full read_zero | |
162934de | 736 | #define aio_write_zero aio_write_null |
1da177e4 LT |
737 | #define open_mem open_port |
738 | #define open_kmem open_mem | |
739 | ||
62322d25 | 740 | static const struct file_operations mem_fops = { |
1da177e4 LT |
741 | .llseek = memory_lseek, |
742 | .read = read_mem, | |
743 | .write = write_mem, | |
744 | .mmap = mmap_mem, | |
745 | .open = open_mem, | |
5da6185b | 746 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 LT |
747 | }; |
748 | ||
b781ecb6 | 749 | #ifdef CONFIG_DEVKMEM |
62322d25 | 750 | static const struct file_operations kmem_fops = { |
1da177e4 LT |
751 | .llseek = memory_lseek, |
752 | .read = read_kmem, | |
753 | .write = write_kmem, | |
754 | .mmap = mmap_kmem, | |
755 | .open = open_kmem, | |
5da6185b | 756 | .get_unmapped_area = get_unmapped_area_mem, |
1da177e4 | 757 | }; |
b781ecb6 | 758 | #endif |
1da177e4 | 759 | |
62322d25 | 760 | static const struct file_operations null_fops = { |
1da177e4 LT |
761 | .llseek = null_lseek, |
762 | .read = read_null, | |
763 | .write = write_null, | |
162934de ZB |
764 | .aio_read = aio_read_null, |
765 | .aio_write = aio_write_null, | |
1ebd32fc | 766 | .splice_write = splice_write_null, |
1da177e4 LT |
767 | }; |
768 | ||
4f911d64 | 769 | #ifdef CONFIG_DEVPORT |
62322d25 | 770 | static const struct file_operations port_fops = { |
1da177e4 LT |
771 | .llseek = memory_lseek, |
772 | .read = read_port, | |
773 | .write = write_port, | |
774 | .open = open_port, | |
775 | }; | |
776 | #endif | |
777 | ||
62322d25 | 778 | static const struct file_operations zero_fops = { |
1da177e4 LT |
779 | .llseek = zero_lseek, |
780 | .read = read_zero, | |
781 | .write = write_zero, | |
162934de ZB |
782 | .aio_read = aio_read_zero, |
783 | .aio_write = aio_write_zero, | |
1da177e4 LT |
784 | .mmap = mmap_zero, |
785 | }; | |
786 | ||
5da6185b DH |
787 | /* |
788 | * capabilities for /dev/zero | |
789 | * - permits private mappings, "copies" are taken of the source of zeros | |
371d217e | 790 | * - no writeback happens |
5da6185b | 791 | */ |
1da177e4 | 792 | static struct backing_dev_info zero_bdi = { |
d993831f | 793 | .name = "char/mem", |
371d217e | 794 | .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK, |
1da177e4 LT |
795 | }; |
796 | ||
62322d25 | 797 | static const struct file_operations full_fops = { |
1da177e4 LT |
798 | .llseek = full_lseek, |
799 | .read = read_full, | |
800 | .write = write_full, | |
801 | }; | |
802 | ||
389e0cb9 KS |
803 | static const struct memdev { |
804 | const char *name; | |
2c9ede55 | 805 | umode_t mode; |
389e0cb9 KS |
806 | const struct file_operations *fops; |
807 | struct backing_dev_info *dev_info; | |
808 | } devlist[] = { | |
e454cea2 | 809 | [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi }, |
b781ecb6 | 810 | #ifdef CONFIG_DEVKMEM |
e454cea2 | 811 | [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi }, |
b781ecb6 | 812 | #endif |
e454cea2 | 813 | [3] = { "null", 0666, &null_fops, NULL }, |
4f911d64 | 814 | #ifdef CONFIG_DEVPORT |
e454cea2 | 815 | [4] = { "port", 0, &port_fops, NULL }, |
1da177e4 | 816 | #endif |
e454cea2 KS |
817 | [5] = { "zero", 0666, &zero_fops, &zero_bdi }, |
818 | [7] = { "full", 0666, &full_fops, NULL }, | |
819 | [8] = { "random", 0666, &random_fops, NULL }, | |
820 | [9] = { "urandom", 0666, &urandom_fops, NULL }, | |
7f3a781d | 821 | #ifdef CONFIG_PRINTK |
e11fea92 | 822 | [11] = { "kmsg", 0644, &kmsg_fops, NULL }, |
7f3a781d | 823 | #endif |
d6f47bef ASF |
824 | }; |
825 | ||
826 | static int memory_open(struct inode *inode, struct file *filp) | |
827 | { | |
389e0cb9 KS |
828 | int minor; |
829 | const struct memdev *dev; | |
d6f47bef | 830 | |
389e0cb9 KS |
831 | minor = iminor(inode); |
832 | if (minor >= ARRAY_SIZE(devlist)) | |
205153aa | 833 | return -ENXIO; |
d6f47bef | 834 | |
389e0cb9 KS |
835 | dev = &devlist[minor]; |
836 | if (!dev->fops) | |
205153aa | 837 | return -ENXIO; |
d6f47bef | 838 | |
389e0cb9 KS |
839 | filp->f_op = dev->fops; |
840 | if (dev->dev_info) | |
841 | filp->f_mapping->backing_dev_info = dev->dev_info; | |
d6f47bef | 842 | |
4a3956c7 KH |
843 | /* Is /dev/mem or /dev/kmem ? */ |
844 | if (dev->dev_info == &directly_mappable_cdev_bdi) | |
845 | filp->f_mode |= FMODE_UNSIGNED_OFFSET; | |
846 | ||
389e0cb9 | 847 | if (dev->fops->open) |
205153aa FW |
848 | return dev->fops->open(inode, filp); |
849 | ||
850 | return 0; | |
1da177e4 LT |
851 | } |
852 | ||
62322d25 | 853 | static const struct file_operations memory_fops = { |
d7d4d849 | 854 | .open = memory_open, |
6038f373 | 855 | .llseek = noop_llseek, |
1da177e4 LT |
856 | }; |
857 | ||
2c9ede55 | 858 | static char *mem_devnode(struct device *dev, umode_t *mode) |
e454cea2 KS |
859 | { |
860 | if (mode && devlist[MINOR(dev->devt)].mode) | |
861 | *mode = devlist[MINOR(dev->devt)].mode; | |
862 | return NULL; | |
863 | } | |
864 | ||
ca8eca68 | 865 | static struct class *mem_class; |
1da177e4 LT |
866 | |
867 | static int __init chr_dev_init(void) | |
868 | { | |
389e0cb9 | 869 | int minor; |
e0bf68dd PZ |
870 | int err; |
871 | ||
872 | err = bdi_init(&zero_bdi); | |
873 | if (err) | |
874 | return err; | |
1da177e4 | 875 | |
d7d4d849 | 876 | if (register_chrdev(MEM_MAJOR, "mem", &memory_fops)) |
1da177e4 LT |
877 | printk("unable to get major %d for memory devs\n", MEM_MAJOR); |
878 | ||
ca8eca68 | 879 | mem_class = class_create(THIS_MODULE, "mem"); |
6e191f7b AB |
880 | if (IS_ERR(mem_class)) |
881 | return PTR_ERR(mem_class); | |
882 | ||
e454cea2 | 883 | mem_class->devnode = mem_devnode; |
389e0cb9 KS |
884 | for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) { |
885 | if (!devlist[minor].name) | |
886 | continue; | |
e1612de9 HM |
887 | |
888 | /* | |
890537b3 | 889 | * Create /dev/port? |
e1612de9 HM |
890 | */ |
891 | if ((minor == DEVPORT_MINOR) && !arch_has_dev_port()) | |
892 | continue; | |
893 | ||
389e0cb9 KS |
894 | device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor), |
895 | NULL, devlist[minor].name); | |
896 | } | |
ebf644c4 | 897 | |
31d1d48e | 898 | return tty_init(); |
1da177e4 LT |
899 | } |
900 | ||
901 | fs_initcall(chr_dev_init); |