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Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * linux/drivers/char/mem.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | * | |
d7d4d849 | 7 | * Added devfs support. |
1da177e4 | 8 | * Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu> |
af901ca1 | 9 | * Shared /dev/zero mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com> |
1da177e4 LT |
10 | */ |
11 | ||
1da177e4 LT |
12 | #include <linux/mm.h> |
13 | #include <linux/miscdevice.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/vmalloc.h> | |
16 | #include <linux/mman.h> | |
17 | #include <linux/random.h> | |
18 | #include <linux/init.h> | |
19 | #include <linux/raw.h> | |
20 | #include <linux/tty.h> | |
21 | #include <linux/capability.h> | |
1da177e4 LT |
22 | #include <linux/ptrace.h> |
23 | #include <linux/device.h> | |
50b1fdbd | 24 | #include <linux/highmem.h> |
1da177e4 | 25 | #include <linux/backing-dev.h> |
c01d5b30 | 26 | #include <linux/shmem_fs.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> |
e2e40f2c | 31 | #include <linux/uio.h> |
1da177e4 | 32 | |
35b6c7e4 | 33 | #include <linux/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 |
a4866aa8 KC |
64 | static inline int page_is_allowed(unsigned long pfn) |
65 | { | |
66 | return devmem_is_allowed(pfn); | |
67 | } | |
e2beb3ea | 68 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 | 69 | { |
e2beb3ea VP |
70 | u64 from = ((u64)pfn) << PAGE_SHIFT; |
71 | u64 to = from + size; | |
72 | u64 cursor = from; | |
73 | ||
74 | while (cursor < to) { | |
39380b80 | 75 | if (!devmem_is_allowed(pfn)) |
ae531c26 | 76 | return 0; |
e2beb3ea VP |
77 | cursor += PAGE_SIZE; |
78 | pfn++; | |
ae531c26 AV |
79 | } |
80 | return 1; | |
81 | } | |
82 | #else | |
a4866aa8 KC |
83 | static inline int page_is_allowed(unsigned long pfn) |
84 | { | |
85 | return 1; | |
86 | } | |
e2beb3ea | 87 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
ae531c26 AV |
88 | { |
89 | return 1; | |
90 | } | |
91 | #endif | |
92 | ||
4707a341 TR |
93 | #ifndef unxlate_dev_mem_ptr |
94 | #define unxlate_dev_mem_ptr unxlate_dev_mem_ptr | |
95 | void __weak unxlate_dev_mem_ptr(phys_addr_t phys, void *addr) | |
e045fb2a | 96 | { |
97 | } | |
4707a341 | 98 | #endif |
e045fb2a | 99 | |
a3424a18 TH |
100 | static inline bool should_stop_iteration(void) |
101 | { | |
102 | if (need_resched()) | |
103 | cond_resched(); | |
104 | return fatal_signal_pending(current); | |
105 | } | |
106 | ||
1da177e4 | 107 | /* |
d7d4d849 AM |
108 | * This funcion reads the *physical* memory. The f_pos points directly to the |
109 | * memory location. | |
1da177e4 | 110 | */ |
d7d4d849 | 111 | static ssize_t read_mem(struct file *file, char __user *buf, |
1da177e4 LT |
112 | size_t count, loff_t *ppos) |
113 | { | |
7e6735c3 | 114 | phys_addr_t p = *ppos; |
1da177e4 | 115 | ssize_t read, sz; |
4707a341 | 116 | void *ptr; |
8057b2aa KC |
117 | char *bounce; |
118 | int err; | |
1da177e4 | 119 | |
08d2d00b PT |
120 | if (p != *ppos) |
121 | return 0; | |
122 | ||
136939a2 | 123 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
124 | return -EFAULT; |
125 | read = 0; | |
126 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
127 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
128 | if (p < PAGE_SIZE) { | |
7fabaddd | 129 | sz = size_inside_page(p, count); |
1da177e4 LT |
130 | if (sz > 0) { |
131 | if (clear_user(buf, sz)) | |
132 | return -EFAULT; | |
d7d4d849 AM |
133 | buf += sz; |
134 | p += sz; | |
135 | count -= sz; | |
136 | read += sz; | |
1da177e4 LT |
137 | } |
138 | } | |
139 | #endif | |
140 | ||
8057b2aa KC |
141 | bounce = kmalloc(PAGE_SIZE, GFP_KERNEL); |
142 | if (!bounce) | |
143 | return -ENOMEM; | |
144 | ||
1da177e4 | 145 | while (count > 0) { |
fa29e97b | 146 | unsigned long remaining; |
7feac526 | 147 | int allowed, probe; |
fa29e97b | 148 | |
f222318e | 149 | sz = size_inside_page(p, count); |
1da177e4 | 150 | |
8057b2aa | 151 | err = -EPERM; |
a4866aa8 KC |
152 | allowed = page_is_allowed(p >> PAGE_SHIFT); |
153 | if (!allowed) | |
8057b2aa KC |
154 | goto failed; |
155 | ||
156 | err = -EFAULT; | |
a4866aa8 KC |
157 | if (allowed == 2) { |
158 | /* Show zeros for restricted memory. */ | |
159 | remaining = clear_user(buf, sz); | |
160 | } else { | |
161 | /* | |
162 | * On ia64 if a page has been mapped somewhere as | |
163 | * uncached, then it must also be accessed uncached | |
164 | * by the kernel or data corruption may occur. | |
165 | */ | |
166 | ptr = xlate_dev_mem_ptr(p); | |
167 | if (!ptr) | |
8057b2aa | 168 | goto failed; |
a4866aa8 | 169 | |
7feac526 | 170 | probe = probe_kernel_read(bounce, ptr, sz); |
a4866aa8 | 171 | unxlate_dev_mem_ptr(p, ptr); |
7feac526 | 172 | if (probe) |
8057b2aa KC |
173 | goto failed; |
174 | ||
175 | remaining = copy_to_user(buf, bounce, sz); | |
a4866aa8 | 176 | } |
1da177e4 | 177 | |
fa29e97b | 178 | if (remaining) |
8057b2aa | 179 | goto failed; |
e045fb2a | 180 | |
1da177e4 LT |
181 | buf += sz; |
182 | p += sz; | |
183 | count -= sz; | |
184 | read += sz; | |
a3424a18 TH |
185 | if (should_stop_iteration()) |
186 | break; | |
1da177e4 | 187 | } |
8057b2aa | 188 | kfree(bounce); |
1da177e4 LT |
189 | |
190 | *ppos += read; | |
191 | return read; | |
8057b2aa KC |
192 | |
193 | failed: | |
194 | kfree(bounce); | |
195 | return err; | |
1da177e4 LT |
196 | } |
197 | ||
d7d4d849 | 198 | static ssize_t write_mem(struct file *file, const char __user *buf, |
1da177e4 LT |
199 | size_t count, loff_t *ppos) |
200 | { | |
7e6735c3 | 201 | phys_addr_t p = *ppos; |
1da177e4 LT |
202 | ssize_t written, sz; |
203 | unsigned long copied; | |
204 | void *ptr; | |
205 | ||
08d2d00b PT |
206 | if (p != *ppos) |
207 | return -EFBIG; | |
208 | ||
136939a2 | 209 | if (!valid_phys_addr_range(p, count)) |
1da177e4 LT |
210 | return -EFAULT; |
211 | ||
212 | written = 0; | |
213 | ||
214 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
215 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
216 | if (p < PAGE_SIZE) { | |
7fabaddd | 217 | sz = size_inside_page(p, count); |
1da177e4 LT |
218 | /* Hmm. Do something? */ |
219 | buf += sz; | |
220 | p += sz; | |
221 | count -= sz; | |
222 | written += sz; | |
223 | } | |
224 | #endif | |
225 | ||
226 | while (count > 0) { | |
a4866aa8 KC |
227 | int allowed; |
228 | ||
f222318e | 229 | sz = size_inside_page(p, count); |
1da177e4 | 230 | |
a4866aa8 KC |
231 | allowed = page_is_allowed(p >> PAGE_SHIFT); |
232 | if (!allowed) | |
e045fb2a | 233 | return -EPERM; |
234 | ||
a4866aa8 KC |
235 | /* Skip actual writing when a page is marked as restricted. */ |
236 | if (allowed == 1) { | |
237 | /* | |
238 | * On ia64 if a page has been mapped somewhere as | |
239 | * uncached, then it must also be accessed uncached | |
240 | * by the kernel or data corruption may occur. | |
241 | */ | |
242 | ptr = xlate_dev_mem_ptr(p); | |
243 | if (!ptr) { | |
244 | if (written) | |
245 | break; | |
246 | return -EFAULT; | |
247 | } | |
248 | ||
249 | copied = copy_from_user(ptr, buf, sz); | |
250 | unxlate_dev_mem_ptr(p, ptr); | |
251 | if (copied) { | |
252 | written += sz - copied; | |
253 | if (written) | |
254 | break; | |
255 | return -EFAULT; | |
256 | } | |
1da177e4 | 257 | } |
e045fb2a | 258 | |
1da177e4 LT |
259 | buf += sz; |
260 | p += sz; | |
261 | count -= sz; | |
262 | written += sz; | |
a3424a18 TH |
263 | if (should_stop_iteration()) |
264 | break; | |
1da177e4 LT |
265 | } |
266 | ||
267 | *ppos += written; | |
268 | return written; | |
269 | } | |
270 | ||
d7d4d849 | 271 | int __weak phys_mem_access_prot_allowed(struct file *file, |
f0970c13 | 272 | unsigned long pfn, unsigned long size, pgprot_t *vma_prot) |
273 | { | |
274 | return 1; | |
275 | } | |
276 | ||
44ac8413 | 277 | #ifndef __HAVE_PHYS_MEM_ACCESS_PROT |
d7d4d849 AM |
278 | |
279 | /* | |
280 | * Architectures vary in how they handle caching for addresses | |
281 | * outside of main memory. | |
282 | * | |
283 | */ | |
ea56f411 | 284 | #ifdef pgprot_noncached |
7e6735c3 | 285 | static int uncached_access(struct file *file, phys_addr_t addr) |
d7d4d849 AM |
286 | { |
287 | #if defined(CONFIG_IA64) | |
288 | /* | |
289 | * On ia64, we ignore O_DSYNC because we cannot tolerate memory | |
290 | * attribute aliases. | |
291 | */ | |
292 | return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); | |
293 | #elif defined(CONFIG_MIPS) | |
294 | { | |
295 | extern int __uncached_access(struct file *file, | |
296 | unsigned long addr); | |
297 | ||
298 | return __uncached_access(file, addr); | |
299 | } | |
300 | #else | |
301 | /* | |
302 | * Accessing memory above the top the kernel knows about or through a | |
303 | * file pointer | |
304 | * that was marked O_DSYNC will be done non-cached. | |
305 | */ | |
306 | if (file->f_flags & O_DSYNC) | |
307 | return 1; | |
308 | return addr >= __pa(high_memory); | |
309 | #endif | |
310 | } | |
ea56f411 | 311 | #endif |
d7d4d849 | 312 | |
44ac8413 BH |
313 | static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, |
314 | unsigned long size, pgprot_t vma_prot) | |
315 | { | |
316 | #ifdef pgprot_noncached | |
7e6735c3 | 317 | phys_addr_t offset = pfn << PAGE_SHIFT; |
44ac8413 BH |
318 | |
319 | if (uncached_access(file, offset)) | |
320 | return pgprot_noncached(vma_prot); | |
321 | #endif | |
322 | return vma_prot; | |
323 | } | |
324 | #endif | |
325 | ||
5da6185b DH |
326 | #ifndef CONFIG_MMU |
327 | static unsigned long get_unmapped_area_mem(struct file *file, | |
328 | unsigned long addr, | |
329 | unsigned long len, | |
330 | unsigned long pgoff, | |
331 | unsigned long flags) | |
332 | { | |
333 | if (!valid_mmap_phys_addr_range(pgoff, len)) | |
334 | return (unsigned long) -EINVAL; | |
8a93258c | 335 | return pgoff << PAGE_SHIFT; |
5da6185b DH |
336 | } |
337 | ||
b4caecd4 CH |
338 | /* permit direct mmap, for read, write or exec */ |
339 | static unsigned memory_mmap_capabilities(struct file *file) | |
340 | { | |
341 | return NOMMU_MAP_DIRECT | | |
342 | NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC; | |
343 | } | |
344 | ||
345 | static unsigned zero_mmap_capabilities(struct file *file) | |
346 | { | |
347 | return NOMMU_MAP_COPY; | |
348 | } | |
349 | ||
5da6185b DH |
350 | /* can't do an in-place private mapping if there's no MMU */ |
351 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
352 | { | |
353 | return vma->vm_flags & VM_MAYSHARE; | |
354 | } | |
355 | #else | |
5da6185b DH |
356 | |
357 | static inline int private_mapping_ok(struct vm_area_struct *vma) | |
358 | { | |
359 | return 1; | |
360 | } | |
361 | #endif | |
362 | ||
f0f37e2f | 363 | static const struct vm_operations_struct mmap_mem_ops = { |
7ae8ed50 RR |
364 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
365 | .access = generic_access_phys | |
366 | #endif | |
e7f260a2 | 367 | }; |
368 | ||
d7d4d849 | 369 | static int mmap_mem(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 370 | { |
80851ef2 | 371 | size_t size = vma->vm_end - vma->vm_start; |
b299cde2 JW |
372 | phys_addr_t offset = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT; |
373 | ||
be62a320 CB |
374 | /* Does it even fit in phys_addr_t? */ |
375 | if (offset >> PAGE_SHIFT != vma->vm_pgoff) | |
376 | return -EINVAL; | |
377 | ||
b299cde2 | 378 | /* It's illegal to wrap around the end of the physical address space. */ |
32829da5 | 379 | if (offset + (phys_addr_t)size - 1 < offset) |
b299cde2 | 380 | return -EINVAL; |
80851ef2 | 381 | |
06c67bef | 382 | if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) |
80851ef2 BH |
383 | return -EINVAL; |
384 | ||
5da6185b DH |
385 | if (!private_mapping_ok(vma)) |
386 | return -ENOSYS; | |
387 | ||
e2beb3ea VP |
388 | if (!range_is_allowed(vma->vm_pgoff, size)) |
389 | return -EPERM; | |
390 | ||
f0970c13 | 391 | if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, |
392 | &vma->vm_page_prot)) | |
393 | return -EINVAL; | |
394 | ||
8b150478 | 395 | vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, |
80851ef2 | 396 | size, |
1da177e4 | 397 | vma->vm_page_prot); |
1da177e4 | 398 | |
e7f260a2 | 399 | vma->vm_ops = &mmap_mem_ops; |
400 | ||
314e51b9 | 401 | /* Remap-pfn-range will mark the range VM_IO */ |
1da177e4 LT |
402 | if (remap_pfn_range(vma, |
403 | vma->vm_start, | |
404 | vma->vm_pgoff, | |
80851ef2 | 405 | size, |
e7f260a2 | 406 | vma->vm_page_prot)) { |
1da177e4 | 407 | return -EAGAIN; |
e7f260a2 | 408 | } |
1da177e4 LT |
409 | return 0; |
410 | } | |
411 | ||
d7d4d849 | 412 | static int mmap_kmem(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 413 | { |
4bb82551 LT |
414 | unsigned long pfn; |
415 | ||
6d3154cc LT |
416 | /* Turn a kernel-virtual address into a physical page frame */ |
417 | pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; | |
4bb82551 | 418 | |
1da177e4 | 419 | /* |
d7d4d849 AM |
420 | * RED-PEN: on some architectures there is more mapped memory than |
421 | * available in mem_map which pfn_valid checks for. Perhaps should add a | |
422 | * new macro here. | |
1da177e4 LT |
423 | * |
424 | * RED-PEN: vmalloc is not supported right now. | |
425 | */ | |
4bb82551 | 426 | if (!pfn_valid(pfn)) |
1da177e4 | 427 | return -EIO; |
4bb82551 LT |
428 | |
429 | vma->vm_pgoff = pfn; | |
1da177e4 LT |
430 | return mmap_mem(file, vma); |
431 | } | |
432 | ||
1da177e4 LT |
433 | /* |
434 | * This function reads the *virtual* memory as seen by the kernel. | |
435 | */ | |
d7d4d849 | 436 | static ssize_t read_kmem(struct file *file, char __user *buf, |
1da177e4 LT |
437 | size_t count, loff_t *ppos) |
438 | { | |
439 | unsigned long p = *ppos; | |
440 | ssize_t low_count, read, sz; | |
890537b3 | 441 | char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ |
325fda71 | 442 | int err = 0; |
1da177e4 LT |
443 | |
444 | read = 0; | |
445 | if (p < (unsigned long) high_memory) { | |
446 | low_count = count; | |
d7d4d849 AM |
447 | if (count > (unsigned long)high_memory - p) |
448 | low_count = (unsigned long)high_memory - p; | |
1da177e4 LT |
449 | |
450 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
451 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
452 | if (p < PAGE_SIZE && low_count > 0) { | |
7fabaddd WF |
453 | sz = size_inside_page(p, low_count); |
454 | if (clear_user(buf, sz)) | |
1da177e4 | 455 | return -EFAULT; |
7fabaddd WF |
456 | buf += sz; |
457 | p += sz; | |
458 | read += sz; | |
459 | low_count -= sz; | |
460 | count -= sz; | |
1da177e4 LT |
461 | } |
462 | #endif | |
463 | while (low_count > 0) { | |
f222318e | 464 | sz = size_inside_page(p, low_count); |
1da177e4 LT |
465 | |
466 | /* | |
467 | * On ia64 if a page has been mapped somewhere as | |
468 | * uncached, then it must also be accessed uncached | |
469 | * by the kernel or data corruption may occur | |
470 | */ | |
4707a341 | 471 | kbuf = xlate_dev_kmem_ptr((void *)p); |
488debb9 RM |
472 | if (!virt_addr_valid(kbuf)) |
473 | return -ENXIO; | |
1da177e4 LT |
474 | |
475 | if (copy_to_user(buf, kbuf, sz)) | |
476 | return -EFAULT; | |
477 | buf += sz; | |
478 | p += sz; | |
479 | read += sz; | |
480 | low_count -= sz; | |
481 | count -= sz; | |
a3424a18 TH |
482 | if (should_stop_iteration()) { |
483 | count = 0; | |
484 | break; | |
485 | } | |
1da177e4 LT |
486 | } |
487 | } | |
488 | ||
489 | if (count > 0) { | |
490 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
491 | if (!kbuf) | |
492 | return -ENOMEM; | |
493 | while (count > 0) { | |
80ad89a0 | 494 | sz = size_inside_page(p, count); |
325fda71 KH |
495 | if (!is_vmalloc_or_module_addr((void *)p)) { |
496 | err = -ENXIO; | |
497 | break; | |
498 | } | |
80ad89a0 WF |
499 | sz = vread(kbuf, (char *)p, sz); |
500 | if (!sz) | |
1da177e4 | 501 | break; |
80ad89a0 | 502 | if (copy_to_user(buf, kbuf, sz)) { |
325fda71 KH |
503 | err = -EFAULT; |
504 | break; | |
1da177e4 | 505 | } |
80ad89a0 WF |
506 | count -= sz; |
507 | buf += sz; | |
508 | read += sz; | |
509 | p += sz; | |
a3424a18 TH |
510 | if (should_stop_iteration()) |
511 | break; | |
1da177e4 LT |
512 | } |
513 | free_page((unsigned long)kbuf); | |
514 | } | |
325fda71 KH |
515 | *ppos = p; |
516 | return read ? read : err; | |
1da177e4 LT |
517 | } |
518 | ||
519 | ||
d7d4d849 AM |
520 | static ssize_t do_write_kmem(unsigned long p, const char __user *buf, |
521 | size_t count, loff_t *ppos) | |
1da177e4 LT |
522 | { |
523 | ssize_t written, sz; | |
524 | unsigned long copied; | |
525 | ||
526 | written = 0; | |
527 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED | |
528 | /* we don't have page 0 mapped on sparc and m68k.. */ | |
ee32398f WF |
529 | if (p < PAGE_SIZE) { |
530 | sz = size_inside_page(p, count); | |
1da177e4 LT |
531 | /* Hmm. Do something? */ |
532 | buf += sz; | |
533 | p += sz; | |
1da177e4 LT |
534 | count -= sz; |
535 | written += sz; | |
536 | } | |
537 | #endif | |
538 | ||
539 | while (count > 0) { | |
4707a341 | 540 | void *ptr; |
1da177e4 | 541 | |
ee32398f | 542 | sz = size_inside_page(p, count); |
1da177e4 LT |
543 | |
544 | /* | |
d7d4d849 AM |
545 | * On ia64 if a page has been mapped somewhere as uncached, then |
546 | * it must also be accessed uncached by the kernel or data | |
547 | * corruption may occur. | |
1da177e4 | 548 | */ |
4707a341 | 549 | ptr = xlate_dev_kmem_ptr((void *)p); |
488debb9 RM |
550 | if (!virt_addr_valid(ptr)) |
551 | return -ENXIO; | |
1da177e4 LT |
552 | |
553 | copied = copy_from_user(ptr, buf, sz); | |
554 | if (copied) { | |
c654d60e JB |
555 | written += sz - copied; |
556 | if (written) | |
557 | break; | |
1da177e4 LT |
558 | return -EFAULT; |
559 | } | |
560 | buf += sz; | |
561 | p += sz; | |
1da177e4 LT |
562 | count -= sz; |
563 | written += sz; | |
a3424a18 TH |
564 | if (should_stop_iteration()) |
565 | break; | |
1da177e4 LT |
566 | } |
567 | ||
568 | *ppos += written; | |
569 | return written; | |
570 | } | |
571 | ||
1da177e4 LT |
572 | /* |
573 | * This function writes to the *virtual* memory as seen by the kernel. | |
574 | */ | |
d7d4d849 | 575 | static ssize_t write_kmem(struct file *file, const char __user *buf, |
1da177e4 LT |
576 | size_t count, loff_t *ppos) |
577 | { | |
578 | unsigned long p = *ppos; | |
579 | ssize_t wrote = 0; | |
580 | ssize_t virtr = 0; | |
890537b3 | 581 | char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ |
325fda71 | 582 | int err = 0; |
1da177e4 LT |
583 | |
584 | if (p < (unsigned long) high_memory) { | |
80ad89a0 WF |
585 | unsigned long to_write = min_t(unsigned long, count, |
586 | (unsigned long)high_memory - p); | |
ee32398f | 587 | wrote = do_write_kmem(p, buf, to_write, ppos); |
80ad89a0 WF |
588 | if (wrote != to_write) |
589 | return wrote; | |
1da177e4 LT |
590 | p += wrote; |
591 | buf += wrote; | |
592 | count -= wrote; | |
593 | } | |
594 | ||
595 | if (count > 0) { | |
596 | kbuf = (char *)__get_free_page(GFP_KERNEL); | |
597 | if (!kbuf) | |
598 | return wrote ? wrote : -ENOMEM; | |
599 | while (count > 0) { | |
80ad89a0 WF |
600 | unsigned long sz = size_inside_page(p, count); |
601 | unsigned long n; | |
1da177e4 | 602 | |
325fda71 KH |
603 | if (!is_vmalloc_or_module_addr((void *)p)) { |
604 | err = -ENXIO; | |
605 | break; | |
606 | } | |
80ad89a0 WF |
607 | n = copy_from_user(kbuf, buf, sz); |
608 | if (n) { | |
325fda71 KH |
609 | err = -EFAULT; |
610 | break; | |
1da177e4 | 611 | } |
c85e9a97 | 612 | vwrite(kbuf, (char *)p, sz); |
80ad89a0 WF |
613 | count -= sz; |
614 | buf += sz; | |
615 | virtr += sz; | |
616 | p += sz; | |
a3424a18 TH |
617 | if (should_stop_iteration()) |
618 | break; | |
1da177e4 LT |
619 | } |
620 | free_page((unsigned long)kbuf); | |
621 | } | |
622 | ||
325fda71 KH |
623 | *ppos = p; |
624 | return virtr + wrote ? : err; | |
1da177e4 LT |
625 | } |
626 | ||
d7d4d849 | 627 | static ssize_t read_port(struct file *file, char __user *buf, |
1da177e4 LT |
628 | size_t count, loff_t *ppos) |
629 | { | |
630 | unsigned long i = *ppos; | |
631 | char __user *tmp = buf; | |
632 | ||
633 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
d7d4d849 | 634 | return -EFAULT; |
1da177e4 | 635 | while (count-- > 0 && i < 65536) { |
d7d4d849 AM |
636 | if (__put_user(inb(i), tmp) < 0) |
637 | return -EFAULT; | |
1da177e4 LT |
638 | i++; |
639 | tmp++; | |
640 | } | |
641 | *ppos = i; | |
642 | return tmp-buf; | |
643 | } | |
644 | ||
d7d4d849 | 645 | static ssize_t write_port(struct file *file, const char __user *buf, |
1da177e4 LT |
646 | size_t count, loff_t *ppos) |
647 | { | |
648 | unsigned long i = *ppos; | |
890537b3 | 649 | const char __user *tmp = buf; |
1da177e4 | 650 | |
d7d4d849 | 651 | if (!access_ok(VERIFY_READ, buf, count)) |
1da177e4 LT |
652 | return -EFAULT; |
653 | while (count-- > 0 && i < 65536) { | |
654 | char c; | |
6a0061ba | 655 | |
c654d60e JB |
656 | if (__get_user(c, tmp)) { |
657 | if (tmp > buf) | |
658 | break; | |
d7d4d849 | 659 | return -EFAULT; |
c654d60e | 660 | } |
d7d4d849 | 661 | outb(c, i); |
1da177e4 LT |
662 | i++; |
663 | tmp++; | |
664 | } | |
665 | *ppos = i; | |
666 | return tmp-buf; | |
667 | } | |
1da177e4 | 668 | |
d7d4d849 | 669 | static ssize_t read_null(struct file *file, char __user *buf, |
1da177e4 LT |
670 | size_t count, loff_t *ppos) |
671 | { | |
672 | return 0; | |
673 | } | |
674 | ||
d7d4d849 | 675 | static ssize_t write_null(struct file *file, const char __user *buf, |
1da177e4 LT |
676 | size_t count, loff_t *ppos) |
677 | { | |
678 | return count; | |
679 | } | |
680 | ||
cd28e28d | 681 | static ssize_t read_iter_null(struct kiocb *iocb, struct iov_iter *to) |
162934de ZB |
682 | { |
683 | return 0; | |
684 | } | |
685 | ||
cd28e28d | 686 | static ssize_t write_iter_null(struct kiocb *iocb, struct iov_iter *from) |
162934de | 687 | { |
cd28e28d AV |
688 | size_t count = iov_iter_count(from); |
689 | iov_iter_advance(from, count); | |
690 | return count; | |
162934de ZB |
691 | } |
692 | ||
1ebd32fc JA |
693 | static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, |
694 | struct splice_desc *sd) | |
695 | { | |
696 | return sd->len; | |
697 | } | |
698 | ||
d7d4d849 | 699 | static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out, |
1ebd32fc JA |
700 | loff_t *ppos, size_t len, unsigned int flags) |
701 | { | |
702 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); | |
703 | } | |
704 | ||
13ba33e8 | 705 | static ssize_t read_iter_zero(struct kiocb *iocb, struct iov_iter *iter) |
1da177e4 | 706 | { |
13ba33e8 | 707 | size_t written = 0; |
1da177e4 | 708 | |
13ba33e8 AV |
709 | while (iov_iter_count(iter)) { |
710 | size_t chunk = iov_iter_count(iter), n; | |
6a0061ba | 711 | |
557ed1fa NP |
712 | if (chunk > PAGE_SIZE) |
713 | chunk = PAGE_SIZE; /* Just for latency reasons */ | |
13ba33e8 AV |
714 | n = iov_iter_zero(chunk, iter); |
715 | if (!n && iov_iter_count(iter)) | |
716 | return written ? written : -EFAULT; | |
717 | written += n; | |
2b838687 LT |
718 | if (signal_pending(current)) |
719 | return written ? written : -ERESTARTSYS; | |
1da177e4 LT |
720 | cond_resched(); |
721 | } | |
13ba33e8 | 722 | return written; |
162934de ZB |
723 | } |
724 | ||
d7d4d849 | 725 | static int mmap_zero(struct file *file, struct vm_area_struct *vma) |
1da177e4 | 726 | { |
557ed1fa | 727 | #ifndef CONFIG_MMU |
1da177e4 | 728 | return -ENOSYS; |
557ed1fa NP |
729 | #endif |
730 | if (vma->vm_flags & VM_SHARED) | |
731 | return shmem_zero_setup(vma); | |
732 | return 0; | |
1da177e4 | 733 | } |
1da177e4 | 734 | |
c01d5b30 HD |
735 | static unsigned long get_unmapped_area_zero(struct file *file, |
736 | unsigned long addr, unsigned long len, | |
737 | unsigned long pgoff, unsigned long flags) | |
738 | { | |
739 | #ifdef CONFIG_MMU | |
740 | if (flags & MAP_SHARED) { | |
741 | /* | |
742 | * mmap_zero() will call shmem_zero_setup() to create a file, | |
743 | * so use shmem's get_unmapped_area in case it can be huge; | |
744 | * and pass NULL for file as in mmap.c's get_unmapped_area(), | |
745 | * so as not to confuse shmem with our handle on "/dev/zero". | |
746 | */ | |
747 | return shmem_get_unmapped_area(NULL, addr, len, pgoff, flags); | |
748 | } | |
749 | ||
750 | /* Otherwise flags & MAP_PRIVATE: with no shmem object beneath it */ | |
751 | return current->mm->get_unmapped_area(file, addr, len, pgoff, flags); | |
752 | #else | |
753 | return -ENOSYS; | |
754 | #endif | |
755 | } | |
756 | ||
d7d4d849 | 757 | static ssize_t write_full(struct file *file, const char __user *buf, |
1da177e4 LT |
758 | size_t count, loff_t *ppos) |
759 | { | |
760 | return -ENOSPC; | |
761 | } | |
762 | ||
763 | /* | |
764 | * Special lseek() function for /dev/null and /dev/zero. Most notably, you | |
765 | * can fopen() both devices with "a" now. This was previously impossible. | |
766 | * -- SRB. | |
767 | */ | |
d7d4d849 | 768 | static loff_t null_lseek(struct file *file, loff_t offset, int orig) |
1da177e4 LT |
769 | { |
770 | return file->f_pos = 0; | |
771 | } | |
772 | ||
773 | /* | |
774 | * The memory devices use the full 32/64 bits of the offset, and so we cannot | |
775 | * check against negative addresses: they are ok. The return value is weird, | |
776 | * though, in that case (0). | |
777 | * | |
778 | * also note that seeking relative to the "end of file" isn't supported: | |
779 | * it has no meaning, so it returns -EINVAL. | |
780 | */ | |
d7d4d849 | 781 | static loff_t memory_lseek(struct file *file, loff_t offset, int orig) |
1da177e4 LT |
782 | { |
783 | loff_t ret; | |
784 | ||
5955102c | 785 | inode_lock(file_inode(file)); |
1da177e4 | 786 | switch (orig) { |
d7d4d849 AM |
787 | case SEEK_CUR: |
788 | offset += file->f_pos; | |
d7d4d849 AM |
789 | case SEEK_SET: |
790 | /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */ | |
ecb63a1b | 791 | if ((unsigned long long)offset >= -MAX_ERRNO) { |
d7d4d849 | 792 | ret = -EOVERFLOW; |
1da177e4 | 793 | break; |
d7d4d849 AM |
794 | } |
795 | file->f_pos = offset; | |
796 | ret = file->f_pos; | |
797 | force_successful_syscall_return(); | |
798 | break; | |
799 | default: | |
800 | ret = -EINVAL; | |
1da177e4 | 801 | } |
5955102c | 802 | inode_unlock(file_inode(file)); |
1da177e4 LT |
803 | return ret; |
804 | } | |
805 | ||
890537b3 | 806 | static int open_port(struct inode *inode, struct file *filp) |
1da177e4 | 807 | { |
0dfddfc6 MG |
808 | if (kernel_is_locked_down("/dev/mem,kmem,port")) |
809 | return -EPERM; | |
1da177e4 LT |
810 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; |
811 | } | |
812 | ||
813 | #define zero_lseek null_lseek | |
814 | #define full_lseek null_lseek | |
815 | #define write_zero write_null | |
cd28e28d | 816 | #define write_iter_zero write_iter_null |
1da177e4 LT |
817 | #define open_mem open_port |
818 | #define open_kmem open_mem | |
819 | ||
73f0718e | 820 | static const struct file_operations __maybe_unused mem_fops = { |
1da177e4 LT |
821 | .llseek = memory_lseek, |
822 | .read = read_mem, | |
823 | .write = write_mem, | |
824 | .mmap = mmap_mem, | |
825 | .open = open_mem, | |
b4caecd4 | 826 | #ifndef CONFIG_MMU |
5da6185b | 827 | .get_unmapped_area = get_unmapped_area_mem, |
b4caecd4 CH |
828 | .mmap_capabilities = memory_mmap_capabilities, |
829 | #endif | |
1da177e4 LT |
830 | }; |
831 | ||
a8c91252 | 832 | static const struct file_operations __maybe_unused kmem_fops = { |
1da177e4 LT |
833 | .llseek = memory_lseek, |
834 | .read = read_kmem, | |
835 | .write = write_kmem, | |
836 | .mmap = mmap_kmem, | |
837 | .open = open_kmem, | |
b4caecd4 | 838 | #ifndef CONFIG_MMU |
5da6185b | 839 | .get_unmapped_area = get_unmapped_area_mem, |
b4caecd4 CH |
840 | .mmap_capabilities = memory_mmap_capabilities, |
841 | #endif | |
1da177e4 LT |
842 | }; |
843 | ||
62322d25 | 844 | static const struct file_operations null_fops = { |
1da177e4 LT |
845 | .llseek = null_lseek, |
846 | .read = read_null, | |
847 | .write = write_null, | |
cd28e28d AV |
848 | .read_iter = read_iter_null, |
849 | .write_iter = write_iter_null, | |
1ebd32fc | 850 | .splice_write = splice_write_null, |
1da177e4 LT |
851 | }; |
852 | ||
3a4bc2fb | 853 | static const struct file_operations __maybe_unused port_fops = { |
1da177e4 LT |
854 | .llseek = memory_lseek, |
855 | .read = read_port, | |
856 | .write = write_port, | |
857 | .open = open_port, | |
858 | }; | |
1da177e4 | 859 | |
62322d25 | 860 | static const struct file_operations zero_fops = { |
1da177e4 | 861 | .llseek = zero_lseek, |
1da177e4 | 862 | .write = write_zero, |
13ba33e8 | 863 | .read_iter = read_iter_zero, |
cd28e28d | 864 | .write_iter = write_iter_zero, |
1da177e4 | 865 | .mmap = mmap_zero, |
c01d5b30 | 866 | .get_unmapped_area = get_unmapped_area_zero, |
b4caecd4 CH |
867 | #ifndef CONFIG_MMU |
868 | .mmap_capabilities = zero_mmap_capabilities, | |
869 | #endif | |
1da177e4 LT |
870 | }; |
871 | ||
62322d25 | 872 | static const struct file_operations full_fops = { |
1da177e4 | 873 | .llseek = full_lseek, |
13ba33e8 | 874 | .read_iter = read_iter_zero, |
1da177e4 LT |
875 | .write = write_full, |
876 | }; | |
877 | ||
389e0cb9 KS |
878 | static const struct memdev { |
879 | const char *name; | |
2c9ede55 | 880 | umode_t mode; |
389e0cb9 | 881 | const struct file_operations *fops; |
b4caecd4 | 882 | fmode_t fmode; |
389e0cb9 | 883 | } devlist[] = { |
73f0718e | 884 | #ifdef CONFIG_DEVMEM |
b4caecd4 | 885 | [1] = { "mem", 0, &mem_fops, FMODE_UNSIGNED_OFFSET }, |
73f0718e | 886 | #endif |
b781ecb6 | 887 | #ifdef CONFIG_DEVKMEM |
b4caecd4 | 888 | [2] = { "kmem", 0, &kmem_fops, FMODE_UNSIGNED_OFFSET }, |
b781ecb6 | 889 | #endif |
b4caecd4 | 890 | [3] = { "null", 0666, &null_fops, 0 }, |
4f911d64 | 891 | #ifdef CONFIG_DEVPORT |
b4caecd4 | 892 | [4] = { "port", 0, &port_fops, 0 }, |
1da177e4 | 893 | #endif |
b4caecd4 CH |
894 | [5] = { "zero", 0666, &zero_fops, 0 }, |
895 | [7] = { "full", 0666, &full_fops, 0 }, | |
896 | [8] = { "random", 0666, &random_fops, 0 }, | |
897 | [9] = { "urandom", 0666, &urandom_fops, 0 }, | |
7f3a781d | 898 | #ifdef CONFIG_PRINTK |
b4caecd4 | 899 | [11] = { "kmsg", 0644, &kmsg_fops, 0 }, |
7f3a781d | 900 | #endif |
d6f47bef ASF |
901 | }; |
902 | ||
903 | static int memory_open(struct inode *inode, struct file *filp) | |
904 | { | |
389e0cb9 KS |
905 | int minor; |
906 | const struct memdev *dev; | |
d6f47bef | 907 | |
389e0cb9 KS |
908 | minor = iminor(inode); |
909 | if (minor >= ARRAY_SIZE(devlist)) | |
205153aa | 910 | return -ENXIO; |
d6f47bef | 911 | |
389e0cb9 KS |
912 | dev = &devlist[minor]; |
913 | if (!dev->fops) | |
205153aa | 914 | return -ENXIO; |
d6f47bef | 915 | |
389e0cb9 | 916 | filp->f_op = dev->fops; |
b4caecd4 | 917 | filp->f_mode |= dev->fmode; |
4a3956c7 | 918 | |
389e0cb9 | 919 | if (dev->fops->open) |
205153aa FW |
920 | return dev->fops->open(inode, filp); |
921 | ||
922 | return 0; | |
1da177e4 LT |
923 | } |
924 | ||
62322d25 | 925 | static const struct file_operations memory_fops = { |
d7d4d849 | 926 | .open = memory_open, |
6038f373 | 927 | .llseek = noop_llseek, |
1da177e4 LT |
928 | }; |
929 | ||
2c9ede55 | 930 | static char *mem_devnode(struct device *dev, umode_t *mode) |
e454cea2 KS |
931 | { |
932 | if (mode && devlist[MINOR(dev->devt)].mode) | |
933 | *mode = devlist[MINOR(dev->devt)].mode; | |
934 | return NULL; | |
935 | } | |
936 | ||
ca8eca68 | 937 | static struct class *mem_class; |
1da177e4 LT |
938 | |
939 | static int __init chr_dev_init(void) | |
940 | { | |
389e0cb9 | 941 | int minor; |
1da177e4 | 942 | |
d7d4d849 | 943 | if (register_chrdev(MEM_MAJOR, "mem", &memory_fops)) |
1da177e4 LT |
944 | printk("unable to get major %d for memory devs\n", MEM_MAJOR); |
945 | ||
ca8eca68 | 946 | mem_class = class_create(THIS_MODULE, "mem"); |
6e191f7b AB |
947 | if (IS_ERR(mem_class)) |
948 | return PTR_ERR(mem_class); | |
949 | ||
e454cea2 | 950 | mem_class->devnode = mem_devnode; |
389e0cb9 KS |
951 | for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) { |
952 | if (!devlist[minor].name) | |
953 | continue; | |
e1612de9 HM |
954 | |
955 | /* | |
890537b3 | 956 | * Create /dev/port? |
e1612de9 HM |
957 | */ |
958 | if ((minor == DEVPORT_MINOR) && !arch_has_dev_port()) | |
959 | continue; | |
960 | ||
389e0cb9 KS |
961 | device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor), |
962 | NULL, devlist[minor].name); | |
963 | } | |
ebf644c4 | 964 | |
31d1d48e | 965 | return tty_init(); |
1da177e4 LT |
966 | } |
967 | ||
968 | fs_initcall(chr_dev_init); |