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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 mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com>
9 */
10
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>
21#include <linux/ptrace.h>
22#include <linux/device.h>
23#include <linux/highmem.h>
24#include <linux/backing-dev.h>
25#include <linux/shmem_fs.h>
26#include <linux/splice.h>
27#include <linux/pfn.h>
28#include <linux/export.h>
29#include <linux/io.h>
30#include <linux/uio.h>
31
32#include <linux/uaccess.h>
33
34#ifdef CONFIG_IA64
35# include <linux/efi.h>
36#endif
37
38#define DEVPORT_MINOR 4
39
40static inline unsigned long size_inside_page(unsigned long start,
41 unsigned long size)
42{
43 unsigned long sz;
44
45 sz = PAGE_SIZE - (start & (PAGE_SIZE - 1));
46
47 return min(sz, size);
48}
49
50#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
51static inline int valid_phys_addr_range(phys_addr_t addr, size_t count)
52{
53 return addr + count <= __pa(high_memory);
54}
55
56static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
57{
58 return 1;
59}
60#endif
61
62#ifdef CONFIG_STRICT_DEVMEM
63static inline int range_is_allowed(unsigned long pfn, unsigned long size)
64{
65 u64 from = ((u64)pfn) << PAGE_SHIFT;
66 u64 to = from + size;
67 u64 cursor = from;
68
69 while (cursor < to) {
70 if (!devmem_is_allowed(pfn))
71 return 0;
72 cursor += PAGE_SIZE;
73 pfn++;
74 }
75 return 1;
76}
77#else
78static inline int range_is_allowed(unsigned long pfn, unsigned long size)
79{
80 return 1;
81}
82#endif
83
84#ifndef unxlate_dev_mem_ptr
85#define unxlate_dev_mem_ptr unxlate_dev_mem_ptr
86void __weak unxlate_dev_mem_ptr(phys_addr_t phys, void *addr)
87{
88}
89#endif
90
91/*
92 * This funcion reads the *physical* memory. The f_pos points directly to the
93 * memory location.
94 */
95static ssize_t read_mem(struct file *file, char __user *buf,
96 size_t count, loff_t *ppos)
97{
98 phys_addr_t p = *ppos;
99 ssize_t read, sz;
100 void *ptr;
101
102 if (p != *ppos)
103 return 0;
104
105 if (!valid_phys_addr_range(p, count))
106 return -EFAULT;
107 read = 0;
108#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
109 /* we don't have page 0 mapped on sparc and m68k.. */
110 if (p < PAGE_SIZE) {
111 sz = size_inside_page(p, count);
112 if (sz > 0) {
113 if (clear_user(buf, sz))
114 return -EFAULT;
115 buf += sz;
116 p += sz;
117 count -= sz;
118 read += sz;
119 }
120 }
121#endif
122
123 while (count > 0) {
124 unsigned long remaining;
125
126 sz = size_inside_page(p, count);
127
128 if (!range_is_allowed(p >> PAGE_SHIFT, count))
129 return -EPERM;
130
131 /*
132 * On ia64 if a page has been mapped somewhere as uncached, then
133 * it must also be accessed uncached by the kernel or data
134 * corruption may occur.
135 */
136 ptr = xlate_dev_mem_ptr(p);
137 if (!ptr)
138 return -EFAULT;
139
140 remaining = copy_to_user(buf, ptr, sz);
141 unxlate_dev_mem_ptr(p, ptr);
142 if (remaining)
143 return -EFAULT;
144
145 buf += sz;
146 p += sz;
147 count -= sz;
148 read += sz;
149 }
150
151 *ppos += read;
152 return read;
153}
154
155static ssize_t write_mem(struct file *file, const char __user *buf,
156 size_t count, loff_t *ppos)
157{
158 phys_addr_t p = *ppos;
159 ssize_t written, sz;
160 unsigned long copied;
161 void *ptr;
162
163 if (p != *ppos)
164 return -EFBIG;
165
166 if (!valid_phys_addr_range(p, count))
167 return -EFAULT;
168
169 written = 0;
170
171#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
172 /* we don't have page 0 mapped on sparc and m68k.. */
173 if (p < PAGE_SIZE) {
174 sz = size_inside_page(p, count);
175 /* Hmm. Do something? */
176 buf += sz;
177 p += sz;
178 count -= sz;
179 written += sz;
180 }
181#endif
182
183 while (count > 0) {
184 sz = size_inside_page(p, count);
185
186 if (!range_is_allowed(p >> PAGE_SHIFT, sz))
187 return -EPERM;
188
189 /*
190 * On ia64 if a page has been mapped somewhere as uncached, then
191 * it must also be accessed uncached by the kernel or data
192 * corruption may occur.
193 */
194 ptr = xlate_dev_mem_ptr(p);
195 if (!ptr) {
196 if (written)
197 break;
198 return -EFAULT;
199 }
200
201 copied = copy_from_user(ptr, buf, sz);
202 unxlate_dev_mem_ptr(p, ptr);
203 if (copied) {
204 written += sz - copied;
205 if (written)
206 break;
207 return -EFAULT;
208 }
209
210 buf += sz;
211 p += sz;
212 count -= sz;
213 written += sz;
214 }
215
216 *ppos += written;
217 return written;
218}
219
220int __weak phys_mem_access_prot_allowed(struct file *file,
221 unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
222{
223 return 1;
224}
225
226#ifndef __HAVE_PHYS_MEM_ACCESS_PROT
227
228/*
229 * Architectures vary in how they handle caching for addresses
230 * outside of main memory.
231 *
232 */
233#ifdef pgprot_noncached
234static int uncached_access(struct file *file, phys_addr_t addr)
235{
236#if defined(CONFIG_IA64)
237 /*
238 * On ia64, we ignore O_DSYNC because we cannot tolerate memory
239 * attribute aliases.
240 */
241 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
242#elif defined(CONFIG_MIPS)
243 {
244 extern int __uncached_access(struct file *file,
245 unsigned long addr);
246
247 return __uncached_access(file, addr);
248 }
249#else
250 /*
251 * Accessing memory above the top the kernel knows about or through a
252 * file pointer
253 * that was marked O_DSYNC will be done non-cached.
254 */
255 if (file->f_flags & O_DSYNC)
256 return 1;
257 return addr >= __pa(high_memory);
258#endif
259}
260#endif
261
262static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
263 unsigned long size, pgprot_t vma_prot)
264{
265#ifdef pgprot_noncached
266 phys_addr_t offset = pfn << PAGE_SHIFT;
267
268 if (uncached_access(file, offset))
269 return pgprot_noncached(vma_prot);
270#endif
271 return vma_prot;
272}
273#endif
274
275#ifndef CONFIG_MMU
276static unsigned long get_unmapped_area_mem(struct file *file,
277 unsigned long addr,
278 unsigned long len,
279 unsigned long pgoff,
280 unsigned long flags)
281{
282 if (!valid_mmap_phys_addr_range(pgoff, len))
283 return (unsigned long) -EINVAL;
284 return pgoff << PAGE_SHIFT;
285}
286
287/* permit direct mmap, for read, write or exec */
288static unsigned memory_mmap_capabilities(struct file *file)
289{
290 return NOMMU_MAP_DIRECT |
291 NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC;
292}
293
294static unsigned zero_mmap_capabilities(struct file *file)
295{
296 return NOMMU_MAP_COPY;
297}
298
299/* can't do an in-place private mapping if there's no MMU */
300static inline int private_mapping_ok(struct vm_area_struct *vma)
301{
302 return vma->vm_flags & VM_MAYSHARE;
303}
304#else
305
306static inline int private_mapping_ok(struct vm_area_struct *vma)
307{
308 return 1;
309}
310#endif
311
312static const struct vm_operations_struct mmap_mem_ops = {
313#ifdef CONFIG_HAVE_IOREMAP_PROT
314 .access = generic_access_phys
315#endif
316};
317
318static int mmap_mem(struct file *file, struct vm_area_struct *vma)
319{
320 size_t size = vma->vm_end - vma->vm_start;
321
322 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
323 return -EINVAL;
324
325 if (!private_mapping_ok(vma))
326 return -ENOSYS;
327
328 if (!range_is_allowed(vma->vm_pgoff, size))
329 return -EPERM;
330
331 if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
332 &vma->vm_page_prot))
333 return -EINVAL;
334
335 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
336 size,
337 vma->vm_page_prot);
338
339 vma->vm_ops = &mmap_mem_ops;
340
341 /* Remap-pfn-range will mark the range VM_IO */
342 if (remap_pfn_range(vma,
343 vma->vm_start,
344 vma->vm_pgoff,
345 size,
346 vma->vm_page_prot)) {
347 return -EAGAIN;
348 }
349 return 0;
350}
351
352static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
353{
354 unsigned long pfn;
355
356 /* Turn a kernel-virtual address into a physical page frame */
357 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
358
359 /*
360 * RED-PEN: on some architectures there is more mapped memory than
361 * available in mem_map which pfn_valid checks for. Perhaps should add a
362 * new macro here.
363 *
364 * RED-PEN: vmalloc is not supported right now.
365 */
366 if (!pfn_valid(pfn))
367 return -EIO;
368
369 vma->vm_pgoff = pfn;
370 return mmap_mem(file, vma);
371}
372
373/*
374 * This function reads the *virtual* memory as seen by the kernel.
375 */
376static ssize_t read_kmem(struct file *file, char __user *buf,
377 size_t count, loff_t *ppos)
378{
379 unsigned long p = *ppos;
380 ssize_t low_count, read, sz;
381 char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
382 int err = 0;
383
384 read = 0;
385 if (p < (unsigned long) high_memory) {
386 low_count = count;
387 if (count > (unsigned long)high_memory - p)
388 low_count = (unsigned long)high_memory - p;
389
390#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
391 /* we don't have page 0 mapped on sparc and m68k.. */
392 if (p < PAGE_SIZE && low_count > 0) {
393 sz = size_inside_page(p, low_count);
394 if (clear_user(buf, sz))
395 return -EFAULT;
396 buf += sz;
397 p += sz;
398 read += sz;
399 low_count -= sz;
400 count -= sz;
401 }
402#endif
403 while (low_count > 0) {
404 sz = size_inside_page(p, low_count);
405
406 /*
407 * On ia64 if a page has been mapped somewhere as
408 * uncached, then it must also be accessed uncached
409 * by the kernel or data corruption may occur
410 */
411 kbuf = xlate_dev_kmem_ptr((void *)p);
412 if (!virt_addr_valid(kbuf))
413 return -ENXIO;
414
415 if (copy_to_user(buf, kbuf, sz))
416 return -EFAULT;
417 buf += sz;
418 p += sz;
419 read += sz;
420 low_count -= sz;
421 count -= sz;
422 }
423 }
424
425 if (count > 0) {
426 kbuf = (char *)__get_free_page(GFP_KERNEL);
427 if (!kbuf)
428 return -ENOMEM;
429 while (count > 0) {
430 sz = size_inside_page(p, count);
431 if (!is_vmalloc_or_module_addr((void *)p)) {
432 err = -ENXIO;
433 break;
434 }
435 sz = vread(kbuf, (char *)p, sz);
436 if (!sz)
437 break;
438 if (copy_to_user(buf, kbuf, sz)) {
439 err = -EFAULT;
440 break;
441 }
442 count -= sz;
443 buf += sz;
444 read += sz;
445 p += sz;
446 }
447 free_page((unsigned long)kbuf);
448 }
449 *ppos = p;
450 return read ? read : err;
451}
452
453
454static ssize_t do_write_kmem(unsigned long p, const char __user *buf,
455 size_t count, loff_t *ppos)
456{
457 ssize_t written, sz;
458 unsigned long copied;
459
460 written = 0;
461#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
462 /* we don't have page 0 mapped on sparc and m68k.. */
463 if (p < PAGE_SIZE) {
464 sz = size_inside_page(p, count);
465 /* Hmm. Do something? */
466 buf += sz;
467 p += sz;
468 count -= sz;
469 written += sz;
470 }
471#endif
472
473 while (count > 0) {
474 void *ptr;
475
476 sz = size_inside_page(p, count);
477
478 /*
479 * On ia64 if a page has been mapped somewhere as uncached, then
480 * it must also be accessed uncached by the kernel or data
481 * corruption may occur.
482 */
483 ptr = xlate_dev_kmem_ptr((void *)p);
484 if (!virt_addr_valid(ptr))
485 return -ENXIO;
486
487 copied = copy_from_user(ptr, buf, sz);
488 if (copied) {
489 written += sz - copied;
490 if (written)
491 break;
492 return -EFAULT;
493 }
494 buf += sz;
495 p += sz;
496 count -= sz;
497 written += sz;
498 }
499
500 *ppos += written;
501 return written;
502}
503
504/*
505 * This function writes to the *virtual* memory as seen by the kernel.
506 */
507static ssize_t write_kmem(struct file *file, const char __user *buf,
508 size_t count, loff_t *ppos)
509{
510 unsigned long p = *ppos;
511 ssize_t wrote = 0;
512 ssize_t virtr = 0;
513 char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
514 int err = 0;
515
516 if (p < (unsigned long) high_memory) {
517 unsigned long to_write = min_t(unsigned long, count,
518 (unsigned long)high_memory - p);
519 wrote = do_write_kmem(p, buf, to_write, ppos);
520 if (wrote != to_write)
521 return wrote;
522 p += wrote;
523 buf += wrote;
524 count -= wrote;
525 }
526
527 if (count > 0) {
528 kbuf = (char *)__get_free_page(GFP_KERNEL);
529 if (!kbuf)
530 return wrote ? wrote : -ENOMEM;
531 while (count > 0) {
532 unsigned long sz = size_inside_page(p, count);
533 unsigned long n;
534
535 if (!is_vmalloc_or_module_addr((void *)p)) {
536 err = -ENXIO;
537 break;
538 }
539 n = copy_from_user(kbuf, buf, sz);
540 if (n) {
541 err = -EFAULT;
542 break;
543 }
544 vwrite(kbuf, (char *)p, sz);
545 count -= sz;
546 buf += sz;
547 virtr += sz;
548 p += sz;
549 }
550 free_page((unsigned long)kbuf);
551 }
552
553 *ppos = p;
554 return virtr + wrote ? : err;
555}
556
557static ssize_t read_port(struct file *file, char __user *buf,
558 size_t count, loff_t *ppos)
559{
560 unsigned long i = *ppos;
561 char __user *tmp = buf;
562
563 if (!access_ok(VERIFY_WRITE, buf, count))
564 return -EFAULT;
565 while (count-- > 0 && i < 65536) {
566 if (__put_user(inb(i), tmp) < 0)
567 return -EFAULT;
568 i++;
569 tmp++;
570 }
571 *ppos = i;
572 return tmp-buf;
573}
574
575static ssize_t write_port(struct file *file, const char __user *buf,
576 size_t count, loff_t *ppos)
577{
578 unsigned long i = *ppos;
579 const char __user *tmp = buf;
580
581 if (!access_ok(VERIFY_READ, buf, count))
582 return -EFAULT;
583 while (count-- > 0 && i < 65536) {
584 char c;
585
586 if (__get_user(c, tmp)) {
587 if (tmp > buf)
588 break;
589 return -EFAULT;
590 }
591 outb(c, i);
592 i++;
593 tmp++;
594 }
595 *ppos = i;
596 return tmp-buf;
597}
598
599static ssize_t read_null(struct file *file, char __user *buf,
600 size_t count, loff_t *ppos)
601{
602 return 0;
603}
604
605static ssize_t write_null(struct file *file, const char __user *buf,
606 size_t count, loff_t *ppos)
607{
608 return count;
609}
610
611static ssize_t read_iter_null(struct kiocb *iocb, struct iov_iter *to)
612{
613 return 0;
614}
615
616static ssize_t write_iter_null(struct kiocb *iocb, struct iov_iter *from)
617{
618 size_t count = iov_iter_count(from);
619 iov_iter_advance(from, count);
620 return count;
621}
622
623static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
624 struct splice_desc *sd)
625{
626 return sd->len;
627}
628
629static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out,
630 loff_t *ppos, size_t len, unsigned int flags)
631{
632 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
633}
634
635static ssize_t read_iter_zero(struct kiocb *iocb, struct iov_iter *iter)
636{
637 size_t written = 0;
638
639 while (iov_iter_count(iter)) {
640 size_t chunk = iov_iter_count(iter), n;
641
642 if (chunk > PAGE_SIZE)
643 chunk = PAGE_SIZE; /* Just for latency reasons */
644 n = iov_iter_zero(chunk, iter);
645 if (!n && iov_iter_count(iter))
646 return written ? written : -EFAULT;
647 written += n;
648 if (signal_pending(current))
649 return written ? written : -ERESTARTSYS;
650 cond_resched();
651 }
652 return written;
653}
654
655static int mmap_zero(struct file *file, struct vm_area_struct *vma)
656{
657#ifndef CONFIG_MMU
658 return -ENOSYS;
659#endif
660 if (vma->vm_flags & VM_SHARED)
661 return shmem_zero_setup(vma);
662 return 0;
663}
664
665static unsigned long get_unmapped_area_zero(struct file *file,
666 unsigned long addr, unsigned long len,
667 unsigned long pgoff, unsigned long flags)
668{
669#ifdef CONFIG_MMU
670 if (flags & MAP_SHARED) {
671 /*
672 * mmap_zero() will call shmem_zero_setup() to create a file,
673 * so use shmem's get_unmapped_area in case it can be huge;
674 * and pass NULL for file as in mmap.c's get_unmapped_area(),
675 * so as not to confuse shmem with our handle on "/dev/zero".
676 */
677 return shmem_get_unmapped_area(NULL, addr, len, pgoff, flags);
678 }
679
680 /* Otherwise flags & MAP_PRIVATE: with no shmem object beneath it */
681 return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
682#else
683 return -ENOSYS;
684#endif
685}
686
687static ssize_t write_full(struct file *file, const char __user *buf,
688 size_t count, loff_t *ppos)
689{
690 return -ENOSPC;
691}
692
693/*
694 * Special lseek() function for /dev/null and /dev/zero. Most notably, you
695 * can fopen() both devices with "a" now. This was previously impossible.
696 * -- SRB.
697 */
698static loff_t null_lseek(struct file *file, loff_t offset, int orig)
699{
700 return file->f_pos = 0;
701}
702
703/*
704 * The memory devices use the full 32/64 bits of the offset, and so we cannot
705 * check against negative addresses: they are ok. The return value is weird,
706 * though, in that case (0).
707 *
708 * also note that seeking relative to the "end of file" isn't supported:
709 * it has no meaning, so it returns -EINVAL.
710 */
711static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
712{
713 loff_t ret;
714
715 inode_lock(file_inode(file));
716 switch (orig) {
717 case SEEK_CUR:
718 offset += file->f_pos;
719 case SEEK_SET:
720 /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */
721 if ((unsigned long long)offset >= -MAX_ERRNO) {
722 ret = -EOVERFLOW;
723 break;
724 }
725 file->f_pos = offset;
726 ret = file->f_pos;
727 force_successful_syscall_return();
728 break;
729 default:
730 ret = -EINVAL;
731 }
732 inode_unlock(file_inode(file));
733 return ret;
734}
735
736static int open_port(struct inode *inode, struct file *filp)
737{
738 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
739}
740
741#define zero_lseek null_lseek
742#define full_lseek null_lseek
743#define write_zero write_null
744#define write_iter_zero write_iter_null
745#define open_mem open_port
746#define open_kmem open_mem
747
748static const struct file_operations __maybe_unused mem_fops = {
749 .llseek = memory_lseek,
750 .read = read_mem,
751 .write = write_mem,
752 .mmap = mmap_mem,
753 .open = open_mem,
754#ifndef CONFIG_MMU
755 .get_unmapped_area = get_unmapped_area_mem,
756 .mmap_capabilities = memory_mmap_capabilities,
757#endif
758};
759
760static const struct file_operations __maybe_unused kmem_fops = {
761 .llseek = memory_lseek,
762 .read = read_kmem,
763 .write = write_kmem,
764 .mmap = mmap_kmem,
765 .open = open_kmem,
766#ifndef CONFIG_MMU
767 .get_unmapped_area = get_unmapped_area_mem,
768 .mmap_capabilities = memory_mmap_capabilities,
769#endif
770};
771
772static const struct file_operations null_fops = {
773 .llseek = null_lseek,
774 .read = read_null,
775 .write = write_null,
776 .read_iter = read_iter_null,
777 .write_iter = write_iter_null,
778 .splice_write = splice_write_null,
779};
780
781static const struct file_operations __maybe_unused port_fops = {
782 .llseek = memory_lseek,
783 .read = read_port,
784 .write = write_port,
785 .open = open_port,
786};
787
788static const struct file_operations zero_fops = {
789 .llseek = zero_lseek,
790 .write = write_zero,
791 .read_iter = read_iter_zero,
792 .write_iter = write_iter_zero,
793 .mmap = mmap_zero,
794 .get_unmapped_area = get_unmapped_area_zero,
795#ifndef CONFIG_MMU
796 .mmap_capabilities = zero_mmap_capabilities,
797#endif
798};
799
800static const struct file_operations full_fops = {
801 .llseek = full_lseek,
802 .read_iter = read_iter_zero,
803 .write = write_full,
804};
805
806static const struct memdev {
807 const char *name;
808 umode_t mode;
809 const struct file_operations *fops;
810 fmode_t fmode;
811} devlist[] = {
812#ifdef CONFIG_DEVMEM
813 [1] = { "mem", 0, &mem_fops, FMODE_UNSIGNED_OFFSET },
814#endif
815#ifdef CONFIG_DEVKMEM
816 [2] = { "kmem", 0, &kmem_fops, FMODE_UNSIGNED_OFFSET },
817#endif
818 [3] = { "null", 0666, &null_fops, 0 },
819#ifdef CONFIG_DEVPORT
820 [4] = { "port", 0, &port_fops, 0 },
821#endif
822 [5] = { "zero", 0666, &zero_fops, 0 },
823 [7] = { "full", 0666, &full_fops, 0 },
824 [8] = { "random", 0666, &random_fops, 0 },
825 [9] = { "urandom", 0666, &urandom_fops, 0 },
826#ifdef CONFIG_PRINTK
827 [11] = { "kmsg", 0644, &kmsg_fops, 0 },
828#endif
829};
830
831static int memory_open(struct inode *inode, struct file *filp)
832{
833 int minor;
834 const struct memdev *dev;
835
836 minor = iminor(inode);
837 if (minor >= ARRAY_SIZE(devlist))
838 return -ENXIO;
839
840 dev = &devlist[minor];
841 if (!dev->fops)
842 return -ENXIO;
843
844 filp->f_op = dev->fops;
845 filp->f_mode |= dev->fmode;
846
847 if (dev->fops->open)
848 return dev->fops->open(inode, filp);
849
850 return 0;
851}
852
853static const struct file_operations memory_fops = {
854 .open = memory_open,
855 .llseek = noop_llseek,
856};
857
858static char *mem_devnode(struct device *dev, umode_t *mode)
859{
860 if (mode && devlist[MINOR(dev->devt)].mode)
861 *mode = devlist[MINOR(dev->devt)].mode;
862 return NULL;
863}
864
865static struct class *mem_class;
866
867static int __init chr_dev_init(void)
868{
869 int minor;
870
871 if (register_chrdev(MEM_MAJOR, "mem", &memory_fops))
872 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
873
874 mem_class = class_create(THIS_MODULE, "mem");
875 if (IS_ERR(mem_class))
876 return PTR_ERR(mem_class);
877
878 mem_class->devnode = mem_devnode;
879 for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
880 if (!devlist[minor].name)
881 continue;
882
883 /*
884 * Create /dev/port?
885 */
886 if ((minor == DEVPORT_MINOR) && !arch_has_dev_port())
887 continue;
888
889 device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
890 NULL, devlist[minor].name);
891 }
892
893 return tty_init();
894}
895
896fs_initcall(chr_dev_init);
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 mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com>
9 */
10
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>
21#include <linux/ptrace.h>
22#include <linux/device.h>
23#include <linux/highmem.h>
24#include <linux/crash_dump.h>
25#include <linux/backing-dev.h>
26#include <linux/bootmem.h>
27#include <linux/splice.h>
28#include <linux/pfn.h>
29#include <linux/export.h>
30
31#include <asm/uaccess.h>
32#include <asm/io.h>
33
34#ifdef CONFIG_IA64
35# include <linux/efi.h>
36#endif
37
38static inline unsigned long size_inside_page(unsigned long start,
39 unsigned long size)
40{
41 unsigned long sz;
42
43 sz = PAGE_SIZE - (start & (PAGE_SIZE - 1));
44
45 return min(sz, size);
46}
47
48#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
49static inline int valid_phys_addr_range(unsigned long addr, size_t count)
50{
51 return addr + count <= __pa(high_memory);
52}
53
54static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
55{
56 return 1;
57}
58#endif
59
60#ifdef CONFIG_STRICT_DEVMEM
61static inline int range_is_allowed(unsigned long pfn, unsigned long size)
62{
63 u64 from = ((u64)pfn) << PAGE_SHIFT;
64 u64 to = from + size;
65 u64 cursor = from;
66
67 while (cursor < to) {
68 if (!devmem_is_allowed(pfn)) {
69 printk(KERN_INFO
70 "Program %s tried to access /dev/mem between %Lx->%Lx.\n",
71 current->comm, from, to);
72 return 0;
73 }
74 cursor += PAGE_SIZE;
75 pfn++;
76 }
77 return 1;
78}
79#else
80static inline int range_is_allowed(unsigned long pfn, unsigned long size)
81{
82 return 1;
83}
84#endif
85
86void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr)
87{
88}
89
90/*
91 * This funcion reads the *physical* memory. The f_pos points directly to the
92 * memory location.
93 */
94static ssize_t read_mem(struct file *file, char __user *buf,
95 size_t count, loff_t *ppos)
96{
97 unsigned long p = *ppos;
98 ssize_t read, sz;
99 char *ptr;
100
101 if (!valid_phys_addr_range(p, count))
102 return -EFAULT;
103 read = 0;
104#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
105 /* we don't have page 0 mapped on sparc and m68k.. */
106 if (p < PAGE_SIZE) {
107 sz = size_inside_page(p, count);
108 if (sz > 0) {
109 if (clear_user(buf, sz))
110 return -EFAULT;
111 buf += sz;
112 p += sz;
113 count -= sz;
114 read += sz;
115 }
116 }
117#endif
118
119 while (count > 0) {
120 unsigned long remaining;
121
122 sz = size_inside_page(p, count);
123
124 if (!range_is_allowed(p >> PAGE_SHIFT, count))
125 return -EPERM;
126
127 /*
128 * On ia64 if a page has been mapped somewhere as uncached, then
129 * it must also be accessed uncached by the kernel or data
130 * corruption may occur.
131 */
132 ptr = xlate_dev_mem_ptr(p);
133 if (!ptr)
134 return -EFAULT;
135
136 remaining = copy_to_user(buf, ptr, sz);
137 unxlate_dev_mem_ptr(p, ptr);
138 if (remaining)
139 return -EFAULT;
140
141 buf += sz;
142 p += sz;
143 count -= sz;
144 read += sz;
145 }
146
147 *ppos += read;
148 return read;
149}
150
151static ssize_t write_mem(struct file *file, const char __user *buf,
152 size_t count, loff_t *ppos)
153{
154 unsigned long p = *ppos;
155 ssize_t written, sz;
156 unsigned long copied;
157 void *ptr;
158
159 if (!valid_phys_addr_range(p, count))
160 return -EFAULT;
161
162 written = 0;
163
164#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
165 /* we don't have page 0 mapped on sparc and m68k.. */
166 if (p < PAGE_SIZE) {
167 sz = size_inside_page(p, count);
168 /* Hmm. Do something? */
169 buf += sz;
170 p += sz;
171 count -= sz;
172 written += sz;
173 }
174#endif
175
176 while (count > 0) {
177 sz = size_inside_page(p, count);
178
179 if (!range_is_allowed(p >> PAGE_SHIFT, sz))
180 return -EPERM;
181
182 /*
183 * On ia64 if a page has been mapped somewhere as uncached, then
184 * it must also be accessed uncached by the kernel or data
185 * corruption may occur.
186 */
187 ptr = xlate_dev_mem_ptr(p);
188 if (!ptr) {
189 if (written)
190 break;
191 return -EFAULT;
192 }
193
194 copied = copy_from_user(ptr, buf, sz);
195 unxlate_dev_mem_ptr(p, ptr);
196 if (copied) {
197 written += sz - copied;
198 if (written)
199 break;
200 return -EFAULT;
201 }
202
203 buf += sz;
204 p += sz;
205 count -= sz;
206 written += sz;
207 }
208
209 *ppos += written;
210 return written;
211}
212
213int __weak phys_mem_access_prot_allowed(struct file *file,
214 unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
215{
216 return 1;
217}
218
219#ifndef __HAVE_PHYS_MEM_ACCESS_PROT
220
221/*
222 * Architectures vary in how they handle caching for addresses
223 * outside of main memory.
224 *
225 */
226#ifdef pgprot_noncached
227static int uncached_access(struct file *file, unsigned long addr)
228{
229#if defined(CONFIG_IA64)
230 /*
231 * On ia64, we ignore O_DSYNC because we cannot tolerate memory
232 * attribute aliases.
233 */
234 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
235#elif defined(CONFIG_MIPS)
236 {
237 extern int __uncached_access(struct file *file,
238 unsigned long addr);
239
240 return __uncached_access(file, addr);
241 }
242#else
243 /*
244 * Accessing memory above the top the kernel knows about or through a
245 * file pointer
246 * that was marked O_DSYNC will be done non-cached.
247 */
248 if (file->f_flags & O_DSYNC)
249 return 1;
250 return addr >= __pa(high_memory);
251#endif
252}
253#endif
254
255static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
256 unsigned long size, pgprot_t vma_prot)
257{
258#ifdef pgprot_noncached
259 unsigned long offset = pfn << PAGE_SHIFT;
260
261 if (uncached_access(file, offset))
262 return pgprot_noncached(vma_prot);
263#endif
264 return vma_prot;
265}
266#endif
267
268#ifndef CONFIG_MMU
269static unsigned long get_unmapped_area_mem(struct file *file,
270 unsigned long addr,
271 unsigned long len,
272 unsigned long pgoff,
273 unsigned long flags)
274{
275 if (!valid_mmap_phys_addr_range(pgoff, len))
276 return (unsigned long) -EINVAL;
277 return pgoff << PAGE_SHIFT;
278}
279
280/* can't do an in-place private mapping if there's no MMU */
281static inline int private_mapping_ok(struct vm_area_struct *vma)
282{
283 return vma->vm_flags & VM_MAYSHARE;
284}
285#else
286#define get_unmapped_area_mem NULL
287
288static inline int private_mapping_ok(struct vm_area_struct *vma)
289{
290 return 1;
291}
292#endif
293
294static const struct vm_operations_struct mmap_mem_ops = {
295#ifdef CONFIG_HAVE_IOREMAP_PROT
296 .access = generic_access_phys
297#endif
298};
299
300static int mmap_mem(struct file *file, struct vm_area_struct *vma)
301{
302 size_t size = vma->vm_end - vma->vm_start;
303
304 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
305 return -EINVAL;
306
307 if (!private_mapping_ok(vma))
308 return -ENOSYS;
309
310 if (!range_is_allowed(vma->vm_pgoff, size))
311 return -EPERM;
312
313 if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
314 &vma->vm_page_prot))
315 return -EINVAL;
316
317 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
318 size,
319 vma->vm_page_prot);
320
321 vma->vm_ops = &mmap_mem_ops;
322
323 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
324 if (remap_pfn_range(vma,
325 vma->vm_start,
326 vma->vm_pgoff,
327 size,
328 vma->vm_page_prot)) {
329 return -EAGAIN;
330 }
331 return 0;
332}
333
334#ifdef CONFIG_DEVKMEM
335static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
336{
337 unsigned long pfn;
338
339 /* Turn a kernel-virtual address into a physical page frame */
340 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
341
342 /*
343 * RED-PEN: on some architectures there is more mapped memory than
344 * available in mem_map which pfn_valid checks for. Perhaps should add a
345 * new macro here.
346 *
347 * RED-PEN: vmalloc is not supported right now.
348 */
349 if (!pfn_valid(pfn))
350 return -EIO;
351
352 vma->vm_pgoff = pfn;
353 return mmap_mem(file, vma);
354}
355#endif
356
357#ifdef CONFIG_CRASH_DUMP
358/*
359 * Read memory corresponding to the old kernel.
360 */
361static ssize_t read_oldmem(struct file *file, char __user *buf,
362 size_t count, loff_t *ppos)
363{
364 unsigned long pfn, offset;
365 size_t read = 0, csize;
366 int rc = 0;
367
368 while (count) {
369 pfn = *ppos / PAGE_SIZE;
370 if (pfn > saved_max_pfn)
371 return read;
372
373 offset = (unsigned long)(*ppos % PAGE_SIZE);
374 if (count > PAGE_SIZE - offset)
375 csize = PAGE_SIZE - offset;
376 else
377 csize = count;
378
379 rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
380 if (rc < 0)
381 return rc;
382 buf += csize;
383 *ppos += csize;
384 read += csize;
385 count -= csize;
386 }
387 return read;
388}
389#endif
390
391#ifdef CONFIG_DEVKMEM
392/*
393 * This function reads the *virtual* memory as seen by the kernel.
394 */
395static ssize_t read_kmem(struct file *file, char __user *buf,
396 size_t count, loff_t *ppos)
397{
398 unsigned long p = *ppos;
399 ssize_t low_count, read, sz;
400 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
401 int err = 0;
402
403 read = 0;
404 if (p < (unsigned long) high_memory) {
405 low_count = count;
406 if (count > (unsigned long)high_memory - p)
407 low_count = (unsigned long)high_memory - p;
408
409#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
410 /* we don't have page 0 mapped on sparc and m68k.. */
411 if (p < PAGE_SIZE && low_count > 0) {
412 sz = size_inside_page(p, low_count);
413 if (clear_user(buf, sz))
414 return -EFAULT;
415 buf += sz;
416 p += sz;
417 read += sz;
418 low_count -= sz;
419 count -= sz;
420 }
421#endif
422 while (low_count > 0) {
423 sz = size_inside_page(p, low_count);
424
425 /*
426 * On ia64 if a page has been mapped somewhere as
427 * uncached, then it must also be accessed uncached
428 * by the kernel or data corruption may occur
429 */
430 kbuf = xlate_dev_kmem_ptr((char *)p);
431
432 if (copy_to_user(buf, kbuf, sz))
433 return -EFAULT;
434 buf += sz;
435 p += sz;
436 read += sz;
437 low_count -= sz;
438 count -= sz;
439 }
440 }
441
442 if (count > 0) {
443 kbuf = (char *)__get_free_page(GFP_KERNEL);
444 if (!kbuf)
445 return -ENOMEM;
446 while (count > 0) {
447 sz = size_inside_page(p, count);
448 if (!is_vmalloc_or_module_addr((void *)p)) {
449 err = -ENXIO;
450 break;
451 }
452 sz = vread(kbuf, (char *)p, sz);
453 if (!sz)
454 break;
455 if (copy_to_user(buf, kbuf, sz)) {
456 err = -EFAULT;
457 break;
458 }
459 count -= sz;
460 buf += sz;
461 read += sz;
462 p += sz;
463 }
464 free_page((unsigned long)kbuf);
465 }
466 *ppos = p;
467 return read ? read : err;
468}
469
470
471static ssize_t do_write_kmem(unsigned long p, const char __user *buf,
472 size_t count, loff_t *ppos)
473{
474 ssize_t written, sz;
475 unsigned long copied;
476
477 written = 0;
478#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
479 /* we don't have page 0 mapped on sparc and m68k.. */
480 if (p < PAGE_SIZE) {
481 sz = size_inside_page(p, count);
482 /* Hmm. Do something? */
483 buf += sz;
484 p += sz;
485 count -= sz;
486 written += sz;
487 }
488#endif
489
490 while (count > 0) {
491 char *ptr;
492
493 sz = size_inside_page(p, count);
494
495 /*
496 * On ia64 if a page has been mapped somewhere as uncached, then
497 * it must also be accessed uncached by the kernel or data
498 * corruption may occur.
499 */
500 ptr = xlate_dev_kmem_ptr((char *)p);
501
502 copied = copy_from_user(ptr, buf, sz);
503 if (copied) {
504 written += sz - copied;
505 if (written)
506 break;
507 return -EFAULT;
508 }
509 buf += sz;
510 p += sz;
511 count -= sz;
512 written += sz;
513 }
514
515 *ppos += written;
516 return written;
517}
518
519/*
520 * This function writes to the *virtual* memory as seen by the kernel.
521 */
522static ssize_t write_kmem(struct file *file, const char __user *buf,
523 size_t count, loff_t *ppos)
524{
525 unsigned long p = *ppos;
526 ssize_t wrote = 0;
527 ssize_t virtr = 0;
528 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
529 int err = 0;
530
531 if (p < (unsigned long) high_memory) {
532 unsigned long to_write = min_t(unsigned long, count,
533 (unsigned long)high_memory - p);
534 wrote = do_write_kmem(p, buf, to_write, ppos);
535 if (wrote != to_write)
536 return wrote;
537 p += wrote;
538 buf += wrote;
539 count -= wrote;
540 }
541
542 if (count > 0) {
543 kbuf = (char *)__get_free_page(GFP_KERNEL);
544 if (!kbuf)
545 return wrote ? wrote : -ENOMEM;
546 while (count > 0) {
547 unsigned long sz = size_inside_page(p, count);
548 unsigned long n;
549
550 if (!is_vmalloc_or_module_addr((void *)p)) {
551 err = -ENXIO;
552 break;
553 }
554 n = copy_from_user(kbuf, buf, sz);
555 if (n) {
556 err = -EFAULT;
557 break;
558 }
559 vwrite(kbuf, (char *)p, sz);
560 count -= sz;
561 buf += sz;
562 virtr += sz;
563 p += sz;
564 }
565 free_page((unsigned long)kbuf);
566 }
567
568 *ppos = p;
569 return virtr + wrote ? : err;
570}
571#endif
572
573#ifdef CONFIG_DEVPORT
574static ssize_t read_port(struct file *file, char __user *buf,
575 size_t count, loff_t *ppos)
576{
577 unsigned long i = *ppos;
578 char __user *tmp = buf;
579
580 if (!access_ok(VERIFY_WRITE, buf, count))
581 return -EFAULT;
582 while (count-- > 0 && i < 65536) {
583 if (__put_user(inb(i), tmp) < 0)
584 return -EFAULT;
585 i++;
586 tmp++;
587 }
588 *ppos = i;
589 return tmp-buf;
590}
591
592static ssize_t write_port(struct file *file, const char __user *buf,
593 size_t count, loff_t *ppos)
594{
595 unsigned long i = *ppos;
596 const char __user * tmp = buf;
597
598 if (!access_ok(VERIFY_READ, buf, count))
599 return -EFAULT;
600 while (count-- > 0 && i < 65536) {
601 char c;
602 if (__get_user(c, tmp)) {
603 if (tmp > buf)
604 break;
605 return -EFAULT;
606 }
607 outb(c, i);
608 i++;
609 tmp++;
610 }
611 *ppos = i;
612 return tmp-buf;
613}
614#endif
615
616static ssize_t read_null(struct file *file, char __user *buf,
617 size_t count, loff_t *ppos)
618{
619 return 0;
620}
621
622static ssize_t write_null(struct file *file, const char __user *buf,
623 size_t count, loff_t *ppos)
624{
625 return count;
626}
627
628static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
629 struct splice_desc *sd)
630{
631 return sd->len;
632}
633
634static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out,
635 loff_t *ppos, size_t len, unsigned int flags)
636{
637 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
638}
639
640static ssize_t read_zero(struct file *file, char __user *buf,
641 size_t count, loff_t *ppos)
642{
643 size_t written;
644
645 if (!count)
646 return 0;
647
648 if (!access_ok(VERIFY_WRITE, buf, count))
649 return -EFAULT;
650
651 written = 0;
652 while (count) {
653 unsigned long unwritten;
654 size_t chunk = count;
655
656 if (chunk > PAGE_SIZE)
657 chunk = PAGE_SIZE; /* Just for latency reasons */
658 unwritten = __clear_user(buf, chunk);
659 written += chunk - unwritten;
660 if (unwritten)
661 break;
662 if (signal_pending(current))
663 return written ? written : -ERESTARTSYS;
664 buf += chunk;
665 count -= chunk;
666 cond_resched();
667 }
668 return written ? written : -EFAULT;
669}
670
671static int mmap_zero(struct file *file, struct vm_area_struct *vma)
672{
673#ifndef CONFIG_MMU
674 return -ENOSYS;
675#endif
676 if (vma->vm_flags & VM_SHARED)
677 return shmem_zero_setup(vma);
678 return 0;
679}
680
681static ssize_t write_full(struct file *file, const char __user *buf,
682 size_t count, loff_t *ppos)
683{
684 return -ENOSPC;
685}
686
687/*
688 * Special lseek() function for /dev/null and /dev/zero. Most notably, you
689 * can fopen() both devices with "a" now. This was previously impossible.
690 * -- SRB.
691 */
692static loff_t null_lseek(struct file *file, loff_t offset, int orig)
693{
694 return file->f_pos = 0;
695}
696
697/*
698 * The memory devices use the full 32/64 bits of the offset, and so we cannot
699 * check against negative addresses: they are ok. The return value is weird,
700 * though, in that case (0).
701 *
702 * also note that seeking relative to the "end of file" isn't supported:
703 * it has no meaning, so it returns -EINVAL.
704 */
705static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
706{
707 loff_t ret;
708
709 mutex_lock(&file->f_path.dentry->d_inode->i_mutex);
710 switch (orig) {
711 case SEEK_CUR:
712 offset += file->f_pos;
713 case SEEK_SET:
714 /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */
715 if ((unsigned long long)offset >= ~0xFFFULL) {
716 ret = -EOVERFLOW;
717 break;
718 }
719 file->f_pos = offset;
720 ret = file->f_pos;
721 force_successful_syscall_return();
722 break;
723 default:
724 ret = -EINVAL;
725 }
726 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
727 return ret;
728}
729
730static int open_port(struct inode * inode, struct file * filp)
731{
732 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
733}
734
735#define zero_lseek null_lseek
736#define full_lseek null_lseek
737#define write_zero write_null
738#define read_full read_zero
739#define open_mem open_port
740#define open_kmem open_mem
741#define open_oldmem open_mem
742
743static const struct file_operations mem_fops = {
744 .llseek = memory_lseek,
745 .read = read_mem,
746 .write = write_mem,
747 .mmap = mmap_mem,
748 .open = open_mem,
749 .get_unmapped_area = get_unmapped_area_mem,
750};
751
752#ifdef CONFIG_DEVKMEM
753static const struct file_operations kmem_fops = {
754 .llseek = memory_lseek,
755 .read = read_kmem,
756 .write = write_kmem,
757 .mmap = mmap_kmem,
758 .open = open_kmem,
759 .get_unmapped_area = get_unmapped_area_mem,
760};
761#endif
762
763static const struct file_operations null_fops = {
764 .llseek = null_lseek,
765 .read = read_null,
766 .write = write_null,
767 .splice_write = splice_write_null,
768};
769
770#ifdef CONFIG_DEVPORT
771static const struct file_operations port_fops = {
772 .llseek = memory_lseek,
773 .read = read_port,
774 .write = write_port,
775 .open = open_port,
776};
777#endif
778
779static const struct file_operations zero_fops = {
780 .llseek = zero_lseek,
781 .read = read_zero,
782 .write = write_zero,
783 .mmap = mmap_zero,
784};
785
786/*
787 * capabilities for /dev/zero
788 * - permits private mappings, "copies" are taken of the source of zeros
789 * - no writeback happens
790 */
791static struct backing_dev_info zero_bdi = {
792 .name = "char/mem",
793 .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK,
794};
795
796static const struct file_operations full_fops = {
797 .llseek = full_lseek,
798 .read = read_full,
799 .write = write_full,
800};
801
802#ifdef CONFIG_CRASH_DUMP
803static const struct file_operations oldmem_fops = {
804 .read = read_oldmem,
805 .open = open_oldmem,
806 .llseek = default_llseek,
807};
808#endif
809
810static const struct memdev {
811 const char *name;
812 umode_t mode;
813 const struct file_operations *fops;
814 struct backing_dev_info *dev_info;
815} devlist[] = {
816 [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi },
817#ifdef CONFIG_DEVKMEM
818 [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi },
819#endif
820 [3] = { "null", 0666, &null_fops, NULL },
821#ifdef CONFIG_DEVPORT
822 [4] = { "port", 0, &port_fops, NULL },
823#endif
824 [5] = { "zero", 0666, &zero_fops, &zero_bdi },
825 [7] = { "full", 0666, &full_fops, NULL },
826 [8] = { "random", 0666, &random_fops, NULL },
827 [9] = { "urandom", 0666, &urandom_fops, NULL },
828#ifdef CONFIG_PRINTK
829 [11] = { "kmsg", 0644, &kmsg_fops, NULL },
830#endif
831#ifdef CONFIG_CRASH_DUMP
832 [12] = { "oldmem", 0, &oldmem_fops, NULL },
833#endif
834};
835
836static int memory_open(struct inode *inode, struct file *filp)
837{
838 int minor;
839 const struct memdev *dev;
840
841 minor = iminor(inode);
842 if (minor >= ARRAY_SIZE(devlist))
843 return -ENXIO;
844
845 dev = &devlist[minor];
846 if (!dev->fops)
847 return -ENXIO;
848
849 filp->f_op = dev->fops;
850 if (dev->dev_info)
851 filp->f_mapping->backing_dev_info = dev->dev_info;
852
853 /* Is /dev/mem or /dev/kmem ? */
854 if (dev->dev_info == &directly_mappable_cdev_bdi)
855 filp->f_mode |= FMODE_UNSIGNED_OFFSET;
856
857 if (dev->fops->open)
858 return dev->fops->open(inode, filp);
859
860 return 0;
861}
862
863static const struct file_operations memory_fops = {
864 .open = memory_open,
865 .llseek = noop_llseek,
866};
867
868static char *mem_devnode(struct device *dev, umode_t *mode)
869{
870 if (mode && devlist[MINOR(dev->devt)].mode)
871 *mode = devlist[MINOR(dev->devt)].mode;
872 return NULL;
873}
874
875static struct class *mem_class;
876
877static int __init chr_dev_init(void)
878{
879 int minor;
880 int err;
881
882 err = bdi_init(&zero_bdi);
883 if (err)
884 return err;
885
886 if (register_chrdev(MEM_MAJOR, "mem", &memory_fops))
887 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
888
889 mem_class = class_create(THIS_MODULE, "mem");
890 if (IS_ERR(mem_class))
891 return PTR_ERR(mem_class);
892
893 mem_class->devnode = mem_devnode;
894 for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
895 if (!devlist[minor].name)
896 continue;
897 device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
898 NULL, devlist[minor].name);
899 }
900
901 return tty_init();
902}
903
904fs_initcall(chr_dev_init);