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