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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 19859 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | /* |
2 | * linux/drivers/char/mem.c |
3 | * |
4 | * Copyright (C) 1991, 1992 Linus Torvalds |
5 | * |
6 | * Added devfs support. |
7 | * Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu> |
8 | * Shared /dev/zero mmaping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com> |
9 | */ |
10 | |
11 | #include <linux/config.h> |
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> |
22 | #include <linux/smp_lock.h> |
23 | #include <linux/devfs_fs_kernel.h> |
24 | #include <linux/ptrace.h> |
25 | #include <linux/device.h> |
26 | #include <linux/backing-dev.h> |
27 | |
28 | #include <asm/uaccess.h> |
29 | #include <asm/io.h> |
30 | |
31 | #ifdef CONFIG_IA64 |
32 | # include <linux/efi.h> |
33 | #endif |
34 | |
35 | #if defined(CONFIG_S390_TAPE) && defined(CONFIG_S390_TAPE_CHAR) |
36 | extern void tapechar_init(void); |
37 | #endif |
38 | |
39 | /* |
40 | * Architectures vary in how they handle caching for addresses |
41 | * outside of main memory. |
42 | * |
43 | */ |
44 | static inline int uncached_access(struct file *file, unsigned long addr) |
45 | { |
46 | #if defined(__i386__) |
47 | /* |
48 | * On the PPro and successors, the MTRRs are used to set |
49 | * memory types for physical addresses outside main memory, |
50 | * so blindly setting PCD or PWT on those pages is wrong. |
51 | * For Pentiums and earlier, the surround logic should disable |
52 | * caching for the high addresses through the KEN pin, but |
53 | * we maintain the tradition of paranoia in this code. |
54 | */ |
55 | if (file->f_flags & O_SYNC) |
56 | return 1; |
57 | return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) || |
58 | test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) || |
59 | test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) || |
60 | test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) ) |
61 | && addr >= __pa(high_memory); |
62 | #elif defined(__x86_64__) |
63 | /* |
64 | * This is broken because it can generate memory type aliases, |
65 | * which can cause cache corruptions |
66 | * But it is only available for root and we have to be bug-to-bug |
67 | * compatible with i386. |
68 | */ |
69 | if (file->f_flags & O_SYNC) |
70 | return 1; |
71 | /* same behaviour as i386. PAT always set to cached and MTRRs control the |
72 | caching behaviour. |
73 | Hopefully a full PAT implementation will fix that soon. */ |
74 | return 0; |
75 | #elif defined(CONFIG_IA64) |
76 | /* |
77 | * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases. |
78 | */ |
79 | return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); |
80 | #else |
81 | /* |
82 | * Accessing memory above the top the kernel knows about or through a file pointer |
83 | * that was marked O_SYNC will be done non-cached. |
84 | */ |
85 | if (file->f_flags & O_SYNC) |
86 | return 1; |
87 | return addr >= __pa(high_memory); |
88 | #endif |
89 | } |
90 | |
91 | #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE |
92 | static inline int valid_phys_addr_range(unsigned long addr, size_t *count) |
93 | { |
94 | unsigned long end_mem; |
95 | |
96 | end_mem = __pa(high_memory); |
97 | if (addr >= end_mem) |
98 | return 0; |
99 | |
100 | if (*count > end_mem - addr) |
101 | *count = end_mem - addr; |
102 | |
103 | return 1; |
104 | } |
105 | #endif |
106 | |
107 | /* |
108 | * This funcion reads the *physical* memory. The f_pos points directly to the |
109 | * memory location. |
110 | */ |
111 | static ssize_t read_mem(struct file * file, char __user * buf, |
112 | size_t count, loff_t *ppos) |
113 | { |
114 | unsigned long p = *ppos; |
115 | ssize_t read, sz; |
116 | char *ptr; |
117 | |
118 | if (!valid_phys_addr_range(p, &count)) |
119 | return -EFAULT; |
120 | read = 0; |
121 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
122 | /* we don't have page 0 mapped on sparc and m68k.. */ |
123 | if (p < PAGE_SIZE) { |
124 | sz = PAGE_SIZE - p; |
125 | if (sz > count) |
126 | sz = count; |
127 | if (sz > 0) { |
128 | if (clear_user(buf, sz)) |
129 | return -EFAULT; |
130 | buf += sz; |
131 | p += sz; |
132 | count -= sz; |
133 | read += sz; |
134 | } |
135 | } |
136 | #endif |
137 | |
138 | while (count > 0) { |
139 | /* |
140 | * Handle first page in case it's not aligned |
141 | */ |
142 | if (-p & (PAGE_SIZE - 1)) |
143 | sz = -p & (PAGE_SIZE - 1); |
144 | else |
145 | sz = PAGE_SIZE; |
146 | |
147 | sz = min_t(unsigned long, sz, count); |
148 | |
149 | /* |
150 | * On ia64 if a page has been mapped somewhere as |
151 | * uncached, then it must also be accessed uncached |
152 | * by the kernel or data corruption may occur |
153 | */ |
154 | ptr = xlate_dev_mem_ptr(p); |
155 | |
156 | if (copy_to_user(buf, ptr, sz)) |
157 | return -EFAULT; |
158 | buf += sz; |
159 | p += sz; |
160 | count -= sz; |
161 | read += sz; |
162 | } |
163 | |
164 | *ppos += read; |
165 | return read; |
166 | } |
167 | |
168 | static ssize_t write_mem(struct file * file, const char __user * buf, |
169 | size_t count, loff_t *ppos) |
170 | { |
171 | unsigned long p = *ppos; |
172 | ssize_t written, sz; |
173 | unsigned long copied; |
174 | void *ptr; |
175 | |
176 | if (!valid_phys_addr_range(p, &count)) |
177 | return -EFAULT; |
178 | |
179 | written = 0; |
180 | |
181 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
182 | /* we don't have page 0 mapped on sparc and m68k.. */ |
183 | if (p < PAGE_SIZE) { |
184 | unsigned long sz = PAGE_SIZE - p; |
185 | if (sz > count) |
186 | sz = count; |
187 | /* Hmm. Do something? */ |
188 | buf += sz; |
189 | p += sz; |
190 | count -= sz; |
191 | written += sz; |
192 | } |
193 | #endif |
194 | |
195 | while (count > 0) { |
196 | /* |
197 | * Handle first page in case it's not aligned |
198 | */ |
199 | if (-p & (PAGE_SIZE - 1)) |
200 | sz = -p & (PAGE_SIZE - 1); |
201 | else |
202 | sz = PAGE_SIZE; |
203 | |
204 | sz = min_t(unsigned long, sz, count); |
205 | |
206 | /* |
207 | * On ia64 if a page has been mapped somewhere as |
208 | * uncached, then it must also be accessed uncached |
209 | * by the kernel or data corruption may occur |
210 | */ |
211 | ptr = xlate_dev_mem_ptr(p); |
212 | |
213 | copied = copy_from_user(ptr, buf, sz); |
214 | if (copied) { |
215 | ssize_t ret; |
216 | |
217 | ret = written + (sz - copied); |
218 | if (ret) |
219 | return ret; |
220 | return -EFAULT; |
221 | } |
222 | buf += sz; |
223 | p += sz; |
224 | count -= sz; |
225 | written += sz; |
226 | } |
227 | |
228 | *ppos += written; |
229 | return written; |
230 | } |
231 | |
232 | static int mmap_mem(struct file * file, struct vm_area_struct * vma) |
233 | { |
234 | #if defined(__HAVE_PHYS_MEM_ACCESS_PROT) |
235 | unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; |
236 | |
237 | vma->vm_page_prot = phys_mem_access_prot(file, offset, |
238 | vma->vm_end - vma->vm_start, |
239 | vma->vm_page_prot); |
240 | #elif defined(pgprot_noncached) |
241 | unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; |
242 | int uncached; |
243 | |
244 | uncached = uncached_access(file, offset); |
245 | if (uncached) |
246 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); |
247 | #endif |
248 | |
249 | /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ |
250 | if (remap_pfn_range(vma, |
251 | vma->vm_start, |
252 | vma->vm_pgoff, |
253 | vma->vm_end-vma->vm_start, |
254 | vma->vm_page_prot)) |
255 | return -EAGAIN; |
256 | return 0; |
257 | } |
258 | |
259 | static int mmap_kmem(struct file * file, struct vm_area_struct * vma) |
260 | { |
261 | unsigned long long val; |
262 | /* |
263 | * RED-PEN: on some architectures there is more mapped memory |
264 | * than available in mem_map which pfn_valid checks |
265 | * for. Perhaps should add a new macro here. |
266 | * |
267 | * RED-PEN: vmalloc is not supported right now. |
268 | */ |
269 | if (!pfn_valid(vma->vm_pgoff)) |
270 | return -EIO; |
271 | val = (u64)vma->vm_pgoff << PAGE_SHIFT; |
272 | vma->vm_pgoff = __pa(val) >> PAGE_SHIFT; |
273 | return mmap_mem(file, vma); |
274 | } |
275 | |
276 | extern long vread(char *buf, char *addr, unsigned long count); |
277 | extern long vwrite(char *buf, char *addr, unsigned long count); |
278 | |
279 | /* |
280 | * This function reads the *virtual* memory as seen by the kernel. |
281 | */ |
282 | static ssize_t read_kmem(struct file *file, char __user *buf, |
283 | size_t count, loff_t *ppos) |
284 | { |
285 | unsigned long p = *ppos; |
286 | ssize_t low_count, read, sz; |
287 | char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ |
288 | |
289 | read = 0; |
290 | if (p < (unsigned long) high_memory) { |
291 | low_count = count; |
292 | if (count > (unsigned long) high_memory - p) |
293 | low_count = (unsigned long) high_memory - p; |
294 | |
295 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
296 | /* we don't have page 0 mapped on sparc and m68k.. */ |
297 | if (p < PAGE_SIZE && low_count > 0) { |
298 | size_t tmp = PAGE_SIZE - p; |
299 | if (tmp > low_count) tmp = low_count; |
300 | if (clear_user(buf, tmp)) |
301 | return -EFAULT; |
302 | buf += tmp; |
303 | p += tmp; |
304 | read += tmp; |
305 | low_count -= tmp; |
306 | count -= tmp; |
307 | } |
308 | #endif |
309 | while (low_count > 0) { |
310 | /* |
311 | * Handle first page in case it's not aligned |
312 | */ |
313 | if (-p & (PAGE_SIZE - 1)) |
314 | sz = -p & (PAGE_SIZE - 1); |
315 | else |
316 | sz = PAGE_SIZE; |
317 | |
318 | sz = min_t(unsigned long, sz, low_count); |
319 | |
320 | /* |
321 | * On ia64 if a page has been mapped somewhere as |
322 | * uncached, then it must also be accessed uncached |
323 | * by the kernel or data corruption may occur |
324 | */ |
325 | kbuf = xlate_dev_kmem_ptr((char *)p); |
326 | |
327 | if (copy_to_user(buf, kbuf, sz)) |
328 | return -EFAULT; |
329 | buf += sz; |
330 | p += sz; |
331 | read += sz; |
332 | low_count -= sz; |
333 | count -= sz; |
334 | } |
335 | } |
336 | |
337 | if (count > 0) { |
338 | kbuf = (char *)__get_free_page(GFP_KERNEL); |
339 | if (!kbuf) |
340 | return -ENOMEM; |
341 | while (count > 0) { |
342 | int len = count; |
343 | |
344 | if (len > PAGE_SIZE) |
345 | len = PAGE_SIZE; |
346 | len = vread(kbuf, (char *)p, len); |
347 | if (!len) |
348 | break; |
349 | if (copy_to_user(buf, kbuf, len)) { |
350 | free_page((unsigned long)kbuf); |
351 | return -EFAULT; |
352 | } |
353 | count -= len; |
354 | buf += len; |
355 | read += len; |
356 | p += len; |
357 | } |
358 | free_page((unsigned long)kbuf); |
359 | } |
360 | *ppos = p; |
361 | return read; |
362 | } |
363 | |
364 | |
365 | static inline ssize_t |
366 | do_write_kmem(void *p, unsigned long realp, const char __user * buf, |
367 | size_t count, loff_t *ppos) |
368 | { |
369 | ssize_t written, sz; |
370 | unsigned long copied; |
371 | |
372 | written = 0; |
373 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
374 | /* we don't have page 0 mapped on sparc and m68k.. */ |
375 | if (realp < PAGE_SIZE) { |
376 | unsigned long sz = PAGE_SIZE - realp; |
377 | if (sz > count) |
378 | sz = count; |
379 | /* Hmm. Do something? */ |
380 | buf += sz; |
381 | p += sz; |
382 | realp += sz; |
383 | count -= sz; |
384 | written += sz; |
385 | } |
386 | #endif |
387 | |
388 | while (count > 0) { |
389 | char *ptr; |
390 | /* |
391 | * Handle first page in case it's not aligned |
392 | */ |
393 | if (-realp & (PAGE_SIZE - 1)) |
394 | sz = -realp & (PAGE_SIZE - 1); |
395 | else |
396 | sz = PAGE_SIZE; |
397 | |
398 | sz = min_t(unsigned long, sz, count); |
399 | |
400 | /* |
401 | * On ia64 if a page has been mapped somewhere as |
402 | * uncached, then it must also be accessed uncached |
403 | * by the kernel or data corruption may occur |
404 | */ |
405 | ptr = xlate_dev_kmem_ptr(p); |
406 | |
407 | copied = copy_from_user(ptr, buf, sz); |
408 | if (copied) { |
409 | ssize_t ret; |
410 | |
411 | ret = written + (sz - copied); |
412 | if (ret) |
413 | return ret; |
414 | return -EFAULT; |
415 | } |
416 | buf += sz; |
417 | p += sz; |
418 | realp += sz; |
419 | count -= sz; |
420 | written += sz; |
421 | } |
422 | |
423 | *ppos += written; |
424 | return written; |
425 | } |
426 | |
427 | |
428 | /* |
429 | * This function writes to the *virtual* memory as seen by the kernel. |
430 | */ |
431 | static ssize_t write_kmem(struct file * file, const char __user * buf, |
432 | size_t count, loff_t *ppos) |
433 | { |
434 | unsigned long p = *ppos; |
435 | ssize_t wrote = 0; |
436 | ssize_t virtr = 0; |
437 | ssize_t written; |
438 | char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ |
439 | |
440 | if (p < (unsigned long) high_memory) { |
441 | |
442 | wrote = count; |
443 | if (count > (unsigned long) high_memory - p) |
444 | wrote = (unsigned long) high_memory - p; |
445 | |
446 | written = do_write_kmem((void*)p, p, buf, wrote, ppos); |
447 | if (written != wrote) |
448 | return written; |
449 | wrote = written; |
450 | p += wrote; |
451 | buf += wrote; |
452 | count -= wrote; |
453 | } |
454 | |
455 | if (count > 0) { |
456 | kbuf = (char *)__get_free_page(GFP_KERNEL); |
457 | if (!kbuf) |
458 | return wrote ? wrote : -ENOMEM; |
459 | while (count > 0) { |
460 | int len = count; |
461 | |
462 | if (len > PAGE_SIZE) |
463 | len = PAGE_SIZE; |
464 | if (len) { |
465 | written = copy_from_user(kbuf, buf, len); |
466 | if (written) { |
467 | ssize_t ret; |
468 | |
469 | free_page((unsigned long)kbuf); |
470 | ret = wrote + virtr + (len - written); |
471 | return ret ? ret : -EFAULT; |
472 | } |
473 | } |
474 | len = vwrite(kbuf, (char *)p, len); |
475 | count -= len; |
476 | buf += len; |
477 | virtr += len; |
478 | p += len; |
479 | } |
480 | free_page((unsigned long)kbuf); |
481 | } |
482 | |
483 | *ppos = p; |
484 | return virtr + wrote; |
485 | } |
486 | |
487 | #if defined(CONFIG_ISA) || !defined(__mc68000__) |
488 | static ssize_t read_port(struct file * file, char __user * buf, |
489 | size_t count, loff_t *ppos) |
490 | { |
491 | unsigned long i = *ppos; |
492 | char __user *tmp = buf; |
493 | |
494 | if (!access_ok(VERIFY_WRITE, buf, count)) |
495 | return -EFAULT; |
496 | while (count-- > 0 && i < 65536) { |
497 | if (__put_user(inb(i),tmp) < 0) |
498 | return -EFAULT; |
499 | i++; |
500 | tmp++; |
501 | } |
502 | *ppos = i; |
503 | return tmp-buf; |
504 | } |
505 | |
506 | static ssize_t write_port(struct file * file, const char __user * buf, |
507 | size_t count, loff_t *ppos) |
508 | { |
509 | unsigned long i = *ppos; |
510 | const char __user * tmp = buf; |
511 | |
512 | if (!access_ok(VERIFY_READ,buf,count)) |
513 | return -EFAULT; |
514 | while (count-- > 0 && i < 65536) { |
515 | char c; |
516 | if (__get_user(c, tmp)) |
517 | return -EFAULT; |
518 | outb(c,i); |
519 | i++; |
520 | tmp++; |
521 | } |
522 | *ppos = i; |
523 | return tmp-buf; |
524 | } |
525 | #endif |
526 | |
527 | static ssize_t read_null(struct file * file, char __user * buf, |
528 | size_t count, loff_t *ppos) |
529 | { |
530 | return 0; |
531 | } |
532 | |
533 | static ssize_t write_null(struct file * file, const char __user * buf, |
534 | size_t count, loff_t *ppos) |
535 | { |
536 | return count; |
537 | } |
538 | |
539 | #ifdef CONFIG_MMU |
540 | /* |
541 | * For fun, we are using the MMU for this. |
542 | */ |
543 | static inline size_t read_zero_pagealigned(char __user * buf, size_t size) |
544 | { |
545 | struct mm_struct *mm; |
546 | struct vm_area_struct * vma; |
547 | unsigned long addr=(unsigned long)buf; |
548 | |
549 | mm = current->mm; |
550 | /* Oops, this was forgotten before. -ben */ |
551 | down_read(&mm->mmap_sem); |
552 | |
553 | /* For private mappings, just map in zero pages. */ |
554 | for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) { |
555 | unsigned long count; |
556 | |
557 | if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0) |
558 | goto out_up; |
559 | if (vma->vm_flags & (VM_SHARED | VM_HUGETLB)) |
560 | break; |
561 | count = vma->vm_end - addr; |
562 | if (count > size) |
563 | count = size; |
564 | |
565 | zap_page_range(vma, addr, count, NULL); |
566 | zeromap_page_range(vma, addr, count, PAGE_COPY); |
567 | |
568 | size -= count; |
569 | buf += count; |
570 | addr += count; |
571 | if (size == 0) |
572 | goto out_up; |
573 | } |
574 | |
575 | up_read(&mm->mmap_sem); |
576 | |
577 | /* The shared case is hard. Let's do the conventional zeroing. */ |
578 | do { |
579 | unsigned long unwritten = clear_user(buf, PAGE_SIZE); |
580 | if (unwritten) |
581 | return size + unwritten - PAGE_SIZE; |
582 | cond_resched(); |
583 | buf += PAGE_SIZE; |
584 | size -= PAGE_SIZE; |
585 | } while (size); |
586 | |
587 | return size; |
588 | out_up: |
589 | up_read(&mm->mmap_sem); |
590 | return size; |
591 | } |
592 | |
593 | static ssize_t read_zero(struct file * file, char __user * buf, |
594 | size_t count, loff_t *ppos) |
595 | { |
596 | unsigned long left, unwritten, written = 0; |
597 | |
598 | if (!count) |
599 | return 0; |
600 | |
601 | if (!access_ok(VERIFY_WRITE, buf, count)) |
602 | return -EFAULT; |
603 | |
604 | left = count; |
605 | |
606 | /* do we want to be clever? Arbitrary cut-off */ |
607 | if (count >= PAGE_SIZE*4) { |
608 | unsigned long partial; |
609 | |
610 | /* How much left of the page? */ |
611 | partial = (PAGE_SIZE-1) & -(unsigned long) buf; |
612 | unwritten = clear_user(buf, partial); |
613 | written = partial - unwritten; |
614 | if (unwritten) |
615 | goto out; |
616 | left -= partial; |
617 | buf += partial; |
618 | unwritten = read_zero_pagealigned(buf, left & PAGE_MASK); |
619 | written += (left & PAGE_MASK) - unwritten; |
620 | if (unwritten) |
621 | goto out; |
622 | buf += left & PAGE_MASK; |
623 | left &= ~PAGE_MASK; |
624 | } |
625 | unwritten = clear_user(buf, left); |
626 | written += left - unwritten; |
627 | out: |
628 | return written ? written : -EFAULT; |
629 | } |
630 | |
631 | static int mmap_zero(struct file * file, struct vm_area_struct * vma) |
632 | { |
633 | if (vma->vm_flags & VM_SHARED) |
634 | return shmem_zero_setup(vma); |
635 | if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot)) |
636 | return -EAGAIN; |
637 | return 0; |
638 | } |
639 | #else /* CONFIG_MMU */ |
640 | static ssize_t read_zero(struct file * file, char * buf, |
641 | size_t count, loff_t *ppos) |
642 | { |
643 | size_t todo = count; |
644 | |
645 | while (todo) { |
646 | size_t chunk = todo; |
647 | |
648 | if (chunk > 4096) |
649 | chunk = 4096; /* Just for latency reasons */ |
650 | if (clear_user(buf, chunk)) |
651 | return -EFAULT; |
652 | buf += chunk; |
653 | todo -= chunk; |
654 | cond_resched(); |
655 | } |
656 | return count; |
657 | } |
658 | |
659 | static int mmap_zero(struct file * file, struct vm_area_struct * vma) |
660 | { |
661 | return -ENOSYS; |
662 | } |
663 | #endif /* CONFIG_MMU */ |
664 | |
665 | static ssize_t write_full(struct file * file, const char __user * buf, |
666 | size_t count, loff_t *ppos) |
667 | { |
668 | return -ENOSPC; |
669 | } |
670 | |
671 | /* |
672 | * Special lseek() function for /dev/null and /dev/zero. Most notably, you |
673 | * can fopen() both devices with "a" now. This was previously impossible. |
674 | * -- SRB. |
675 | */ |
676 | |
677 | static loff_t null_lseek(struct file * file, loff_t offset, int orig) |
678 | { |
679 | return file->f_pos = 0; |
680 | } |
681 | |
682 | /* |
683 | * The memory devices use the full 32/64 bits of the offset, and so we cannot |
684 | * check against negative addresses: they are ok. The return value is weird, |
685 | * though, in that case (0). |
686 | * |
687 | * also note that seeking relative to the "end of file" isn't supported: |
688 | * it has no meaning, so it returns -EINVAL. |
689 | */ |
690 | static loff_t memory_lseek(struct file * file, loff_t offset, int orig) |
691 | { |
692 | loff_t ret; |
693 | |
694 | down(&file->f_dentry->d_inode->i_sem); |
695 | switch (orig) { |
696 | case 0: |
697 | file->f_pos = offset; |
698 | ret = file->f_pos; |
699 | force_successful_syscall_return(); |
700 | break; |
701 | case 1: |
702 | file->f_pos += offset; |
703 | ret = file->f_pos; |
704 | force_successful_syscall_return(); |
705 | break; |
706 | default: |
707 | ret = -EINVAL; |
708 | } |
709 | up(&file->f_dentry->d_inode->i_sem); |
710 | return ret; |
711 | } |
712 | |
713 | static int open_port(struct inode * inode, struct file * filp) |
714 | { |
715 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; |
716 | } |
717 | |
718 | #define zero_lseek null_lseek |
719 | #define full_lseek null_lseek |
720 | #define write_zero write_null |
721 | #define read_full read_zero |
722 | #define open_mem open_port |
723 | #define open_kmem open_mem |
724 | |
725 | static struct file_operations mem_fops = { |
726 | .llseek = memory_lseek, |
727 | .read = read_mem, |
728 | .write = write_mem, |
729 | .mmap = mmap_mem, |
730 | .open = open_mem, |
731 | }; |
732 | |
733 | static struct file_operations kmem_fops = { |
734 | .llseek = memory_lseek, |
735 | .read = read_kmem, |
736 | .write = write_kmem, |
737 | .mmap = mmap_kmem, |
738 | .open = open_kmem, |
739 | }; |
740 | |
741 | static struct file_operations null_fops = { |
742 | .llseek = null_lseek, |
743 | .read = read_null, |
744 | .write = write_null, |
745 | }; |
746 | |
747 | #if defined(CONFIG_ISA) || !defined(__mc68000__) |
748 | static struct file_operations port_fops = { |
749 | .llseek = memory_lseek, |
750 | .read = read_port, |
751 | .write = write_port, |
752 | .open = open_port, |
753 | }; |
754 | #endif |
755 | |
756 | static struct file_operations zero_fops = { |
757 | .llseek = zero_lseek, |
758 | .read = read_zero, |
759 | .write = write_zero, |
760 | .mmap = mmap_zero, |
761 | }; |
762 | |
763 | static struct backing_dev_info zero_bdi = { |
764 | .capabilities = BDI_CAP_MAP_COPY, |
765 | }; |
766 | |
767 | static struct file_operations full_fops = { |
768 | .llseek = full_lseek, |
769 | .read = read_full, |
770 | .write = write_full, |
771 | }; |
772 | |
773 | static ssize_t kmsg_write(struct file * file, const char __user * buf, |
774 | size_t count, loff_t *ppos) |
775 | { |
776 | char *tmp; |
777 | int ret; |
778 | |
779 | tmp = kmalloc(count + 1, GFP_KERNEL); |
780 | if (tmp == NULL) |
781 | return -ENOMEM; |
782 | ret = -EFAULT; |
783 | if (!copy_from_user(tmp, buf, count)) { |
784 | tmp[count] = 0; |
785 | ret = printk("%s", tmp); |
786 | } |
787 | kfree(tmp); |
788 | return ret; |
789 | } |
790 | |
791 | static struct file_operations kmsg_fops = { |
792 | .write = kmsg_write, |
793 | }; |
794 | |
795 | static int memory_open(struct inode * inode, struct file * filp) |
796 | { |
797 | switch (iminor(inode)) { |
798 | case 1: |
799 | filp->f_op = &mem_fops; |
800 | break; |
801 | case 2: |
802 | filp->f_op = &kmem_fops; |
803 | break; |
804 | case 3: |
805 | filp->f_op = &null_fops; |
806 | break; |
807 | #if defined(CONFIG_ISA) || !defined(__mc68000__) |
808 | case 4: |
809 | filp->f_op = &port_fops; |
810 | break; |
811 | #endif |
812 | case 5: |
813 | filp->f_mapping->backing_dev_info = &zero_bdi; |
814 | filp->f_op = &zero_fops; |
815 | break; |
816 | case 7: |
817 | filp->f_op = &full_fops; |
818 | break; |
819 | case 8: |
820 | filp->f_op = &random_fops; |
821 | break; |
822 | case 9: |
823 | filp->f_op = &urandom_fops; |
824 | break; |
825 | case 11: |
826 | filp->f_op = &kmsg_fops; |
827 | break; |
828 | default: |
829 | return -ENXIO; |
830 | } |
831 | if (filp->f_op && filp->f_op->open) |
832 | return filp->f_op->open(inode,filp); |
833 | return 0; |
834 | } |
835 | |
836 | static struct file_operations memory_fops = { |
837 | .open = memory_open, /* just a selector for the real open */ |
838 | }; |
839 | |
840 | static const struct { |
841 | unsigned int minor; |
842 | char *name; |
843 | umode_t mode; |
844 | struct file_operations *fops; |
845 | } devlist[] = { /* list of minor devices */ |
846 | {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops}, |
847 | {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops}, |
848 | {3, "null", S_IRUGO | S_IWUGO, &null_fops}, |
849 | #if defined(CONFIG_ISA) || !defined(__mc68000__) |
850 | {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops}, |
851 | #endif |
852 | {5, "zero", S_IRUGO | S_IWUGO, &zero_fops}, |
853 | {7, "full", S_IRUGO | S_IWUGO, &full_fops}, |
854 | {8, "random", S_IRUGO | S_IWUSR, &random_fops}, |
855 | {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops}, |
856 | {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops}, |
857 | }; |
858 | |
859 | static struct class_simple *mem_class; |
860 | |
861 | static int __init chr_dev_init(void) |
862 | { |
863 | int i; |
864 | |
865 | if (register_chrdev(MEM_MAJOR,"mem",&memory_fops)) |
866 | printk("unable to get major %d for memory devs\n", MEM_MAJOR); |
867 | |
868 | mem_class = class_simple_create(THIS_MODULE, "mem"); |
869 | for (i = 0; i < ARRAY_SIZE(devlist); i++) { |
870 | class_simple_device_add(mem_class, |
871 | MKDEV(MEM_MAJOR, devlist[i].minor), |
872 | NULL, devlist[i].name); |
873 | devfs_mk_cdev(MKDEV(MEM_MAJOR, devlist[i].minor), |
874 | S_IFCHR | devlist[i].mode, devlist[i].name); |
875 | } |
876 | |
877 | return 0; |
878 | } |
879 | |
880 | fs_initcall(chr_dev_init); |