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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/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
30#include <asm/uaccess.h>
31#include <asm/io.h>
32
33#ifdef CONFIG_IA64
34# include <linux/efi.h>
35#endif
36
37static inline unsigned long size_inside_page(unsigned long start,
38 unsigned long size)
39{
40 unsigned long sz;
41
42 sz = PAGE_SIZE - (start & (PAGE_SIZE - 1));
43
44 return min(sz, size);
45}
46
47#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
48static inline int valid_phys_addr_range(unsigned long addr, size_t count)
49{
50 return addr + count <= __pa(high_memory);
51}
52
53static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
54{
55 return 1;
56}
57#endif
58
59#ifdef CONFIG_STRICT_DEVMEM
60static inline int range_is_allowed(unsigned long pfn, unsigned long size)
61{
62 u64 from = ((u64)pfn) << PAGE_SHIFT;
63 u64 to = from + size;
64 u64 cursor = from;
65
66 while (cursor < to) {
67 if (!devmem_is_allowed(pfn)) {
68 printk(KERN_INFO
69 "Program %s tried to access /dev/mem between %Lx->%Lx.\n",
70 current->comm, from, to);
71 return 0;
72 }
73 cursor += PAGE_SIZE;
74 pfn++;
75 }
76 return 1;
77}
78#else
79static inline int range_is_allowed(unsigned long pfn, unsigned long size)
80{
81 return 1;
82}
83#endif
84
85void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr)
86{
87}
88
89/*
90 * This funcion reads the *physical* memory. The f_pos points directly to the
91 * memory location.
92 */
93static ssize_t read_mem(struct file *file, char __user *buf,
94 size_t count, loff_t *ppos)
95{
96 unsigned long p = *ppos;
97 ssize_t read, sz;
98 char *ptr;
99
100 if (!valid_phys_addr_range(p, count))
101 return -EFAULT;
102 read = 0;
103#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
104 /* we don't have page 0 mapped on sparc and m68k.. */
105 if (p < PAGE_SIZE) {
106 sz = size_inside_page(p, count);
107 if (sz > 0) {
108 if (clear_user(buf, sz))
109 return -EFAULT;
110 buf += sz;
111 p += sz;
112 count -= sz;
113 read += sz;
114 }
115 }
116#endif
117
118 while (count > 0) {
119 unsigned long remaining;
120
121 sz = size_inside_page(p, count);
122
123 if (!range_is_allowed(p >> PAGE_SHIFT, count))
124 return -EPERM;
125
126 /*
127 * On ia64 if a page has been mapped somewhere as uncached, then
128 * it must also be accessed uncached by the kernel or data
129 * corruption may occur.
130 */
131 ptr = xlate_dev_mem_ptr(p);
132 if (!ptr)
133 return -EFAULT;
134
135 remaining = copy_to_user(buf, ptr, sz);
136 unxlate_dev_mem_ptr(p, ptr);
137 if (remaining)
138 return -EFAULT;
139
140 buf += sz;
141 p += sz;
142 count -= sz;
143 read += sz;
144 }
145
146 *ppos += read;
147 return read;
148}
149
150static ssize_t write_mem(struct file *file, const char __user *buf,
151 size_t count, loff_t *ppos)
152{
153 unsigned long p = *ppos;
154 ssize_t written, sz;
155 unsigned long copied;
156 void *ptr;
157
158 if (!valid_phys_addr_range(p, count))
159 return -EFAULT;
160
161 written = 0;
162
163#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
164 /* we don't have page 0 mapped on sparc and m68k.. */
165 if (p < PAGE_SIZE) {
166 sz = size_inside_page(p, count);
167 /* Hmm. Do something? */
168 buf += sz;
169 p += sz;
170 count -= sz;
171 written += sz;
172 }
173#endif
174
175 while (count > 0) {
176 sz = size_inside_page(p, count);
177
178 if (!range_is_allowed(p >> PAGE_SHIFT, sz))
179 return -EPERM;
180
181 /*
182 * On ia64 if a page has been mapped somewhere as uncached, then
183 * it must also be accessed uncached by the kernel or data
184 * corruption may occur.
185 */
186 ptr = xlate_dev_mem_ptr(p);
187 if (!ptr) {
188 if (written)
189 break;
190 return -EFAULT;
191 }
192
193 copied = copy_from_user(ptr, buf, sz);
194 unxlate_dev_mem_ptr(p, ptr);
195 if (copied) {
196 written += sz - copied;
197 if (written)
198 break;
199 return -EFAULT;
200 }
201
202 buf += sz;
203 p += sz;
204 count -= sz;
205 written += sz;
206 }
207
208 *ppos += written;
209 return written;
210}
211
212int __weak phys_mem_access_prot_allowed(struct file *file,
213 unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
214{
215 return 1;
216}
217
218#ifndef __HAVE_PHYS_MEM_ACCESS_PROT
219
220/*
221 * Architectures vary in how they handle caching for addresses
222 * outside of main memory.
223 *
224 */
225#ifdef pgprot_noncached
226static int uncached_access(struct file *file, unsigned long addr)
227{
228#if defined(CONFIG_IA64)
229 /*
230 * On ia64, we ignore O_DSYNC because we cannot tolerate memory
231 * attribute aliases.
232 */
233 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
234#elif defined(CONFIG_MIPS)
235 {
236 extern int __uncached_access(struct file *file,
237 unsigned long addr);
238
239 return __uncached_access(file, addr);
240 }
241#else
242 /*
243 * Accessing memory above the top the kernel knows about or through a
244 * file pointer
245 * that was marked O_DSYNC will be done non-cached.
246 */
247 if (file->f_flags & O_DSYNC)
248 return 1;
249 return addr >= __pa(high_memory);
250#endif
251}
252#endif
253
254static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
255 unsigned long size, pgprot_t vma_prot)
256{
257#ifdef pgprot_noncached
258 unsigned long offset = pfn << PAGE_SHIFT;
259
260 if (uncached_access(file, offset))
261 return pgprot_noncached(vma_prot);
262#endif
263 return vma_prot;
264}
265#endif
266
267#ifndef CONFIG_MMU
268static unsigned long get_unmapped_area_mem(struct file *file,
269 unsigned long addr,
270 unsigned long len,
271 unsigned long pgoff,
272 unsigned long flags)
273{
274 if (!valid_mmap_phys_addr_range(pgoff, len))
275 return (unsigned long) -EINVAL;
276 return pgoff << PAGE_SHIFT;
277}
278
279/* can't do an in-place private mapping if there's no MMU */
280static inline int private_mapping_ok(struct vm_area_struct *vma)
281{
282 return vma->vm_flags & VM_MAYSHARE;
283}
284#else
285#define get_unmapped_area_mem NULL
286
287static inline int private_mapping_ok(struct vm_area_struct *vma)
288{
289 return 1;
290}
291#endif
292
293static const struct vm_operations_struct mmap_mem_ops = {
294#ifdef CONFIG_HAVE_IOREMAP_PROT
295 .access = generic_access_phys
296#endif
297};
298
299static int mmap_mem(struct file *file, struct vm_area_struct *vma)
300{
301 size_t size = vma->vm_end - vma->vm_start;
302
303 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
304 return -EINVAL;
305
306 if (!private_mapping_ok(vma))
307 return -ENOSYS;
308
309 if (!range_is_allowed(vma->vm_pgoff, size))
310 return -EPERM;
311
312 if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
313 &vma->vm_page_prot))
314 return -EINVAL;
315
316 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
317 size,
318 vma->vm_page_prot);
319
320 vma->vm_ops = &mmap_mem_ops;
321
322 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
323 if (remap_pfn_range(vma,
324 vma->vm_start,
325 vma->vm_pgoff,
326 size,
327 vma->vm_page_prot)) {
328 return -EAGAIN;
329 }
330 return 0;
331}
332
333#ifdef CONFIG_DEVKMEM
334static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
335{
336 unsigned long pfn;
337
338 /* Turn a kernel-virtual address into a physical page frame */
339 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
340
341 /*
342 * RED-PEN: on some architectures there is more mapped memory than
343 * available in mem_map which pfn_valid checks for. Perhaps should add a
344 * new macro here.
345 *
346 * RED-PEN: vmalloc is not supported right now.
347 */
348 if (!pfn_valid(pfn))
349 return -EIO;
350
351 vma->vm_pgoff = pfn;
352 return mmap_mem(file, vma);
353}
354#endif
355
356#ifdef CONFIG_CRASH_DUMP
357/*
358 * Read memory corresponding to the old kernel.
359 */
360static ssize_t read_oldmem(struct file *file, char __user *buf,
361 size_t count, loff_t *ppos)
362{
363 unsigned long pfn, offset;
364 size_t read = 0, csize;
365 int rc = 0;
366
367 while (count) {
368 pfn = *ppos / PAGE_SIZE;
369 if (pfn > saved_max_pfn)
370 return read;
371
372 offset = (unsigned long)(*ppos % PAGE_SIZE);
373 if (count > PAGE_SIZE - offset)
374 csize = PAGE_SIZE - offset;
375 else
376 csize = count;
377
378 rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
379 if (rc < 0)
380 return rc;
381 buf += csize;
382 *ppos += csize;
383 read += csize;
384 count -= csize;
385 }
386 return read;
387}
388#endif
389
390#ifdef CONFIG_DEVKMEM
391/*
392 * This function reads the *virtual* memory as seen by the kernel.
393 */
394static ssize_t read_kmem(struct file *file, char __user *buf,
395 size_t count, loff_t *ppos)
396{
397 unsigned long p = *ppos;
398 ssize_t low_count, read, sz;
399 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
400 int err = 0;
401
402 read = 0;
403 if (p < (unsigned long) high_memory) {
404 low_count = count;
405 if (count > (unsigned long)high_memory - p)
406 low_count = (unsigned long)high_memory - p;
407
408#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
409 /* we don't have page 0 mapped on sparc and m68k.. */
410 if (p < PAGE_SIZE && low_count > 0) {
411 sz = size_inside_page(p, low_count);
412 if (clear_user(buf, sz))
413 return -EFAULT;
414 buf += sz;
415 p += sz;
416 read += sz;
417 low_count -= sz;
418 count -= sz;
419 }
420#endif
421 while (low_count > 0) {
422 sz = size_inside_page(p, low_count);
423
424 /*
425 * On ia64 if a page has been mapped somewhere as
426 * uncached, then it must also be accessed uncached
427 * by the kernel or data corruption may occur
428 */
429 kbuf = xlate_dev_kmem_ptr((char *)p);
430
431 if (copy_to_user(buf, kbuf, sz))
432 return -EFAULT;
433 buf += sz;
434 p += sz;
435 read += sz;
436 low_count -= sz;
437 count -= sz;
438 }
439 }
440
441 if (count > 0) {
442 kbuf = (char *)__get_free_page(GFP_KERNEL);
443 if (!kbuf)
444 return -ENOMEM;
445 while (count > 0) {
446 sz = size_inside_page(p, count);
447 if (!is_vmalloc_or_module_addr((void *)p)) {
448 err = -ENXIO;
449 break;
450 }
451 sz = vread(kbuf, (char *)p, sz);
452 if (!sz)
453 break;
454 if (copy_to_user(buf, kbuf, sz)) {
455 err = -EFAULT;
456 break;
457 }
458 count -= sz;
459 buf += sz;
460 read += sz;
461 p += sz;
462 }
463 free_page((unsigned long)kbuf);
464 }
465 *ppos = p;
466 return read ? read : err;
467}
468
469
470static ssize_t do_write_kmem(unsigned long p, const char __user *buf,
471 size_t count, loff_t *ppos)
472{
473 ssize_t written, sz;
474 unsigned long copied;
475
476 written = 0;
477#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
478 /* we don't have page 0 mapped on sparc and m68k.. */
479 if (p < PAGE_SIZE) {
480 sz = size_inside_page(p, count);
481 /* Hmm. Do something? */
482 buf += sz;
483 p += sz;
484 count -= sz;
485 written += sz;
486 }
487#endif
488
489 while (count > 0) {
490 char *ptr;
491
492 sz = size_inside_page(p, count);
493
494 /*
495 * On ia64 if a page has been mapped somewhere as uncached, then
496 * it must also be accessed uncached by the kernel or data
497 * corruption may occur.
498 */
499 ptr = xlate_dev_kmem_ptr((char *)p);
500
501 copied = copy_from_user(ptr, buf, sz);
502 if (copied) {
503 written += sz - copied;
504 if (written)
505 break;
506 return -EFAULT;
507 }
508 buf += sz;
509 p += sz;
510 count -= sz;
511 written += sz;
512 }
513
514 *ppos += written;
515 return written;
516}
517
518/*
519 * This function writes to the *virtual* memory as seen by the kernel.
520 */
521static ssize_t write_kmem(struct file *file, const char __user *buf,
522 size_t count, loff_t *ppos)
523{
524 unsigned long p = *ppos;
525 ssize_t wrote = 0;
526 ssize_t virtr = 0;
527 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
528 int err = 0;
529
530 if (p < (unsigned long) high_memory) {
531 unsigned long to_write = min_t(unsigned long, count,
532 (unsigned long)high_memory - p);
533 wrote = do_write_kmem(p, buf, to_write, ppos);
534 if (wrote != to_write)
535 return wrote;
536 p += wrote;
537 buf += wrote;
538 count -= wrote;
539 }
540
541 if (count > 0) {
542 kbuf = (char *)__get_free_page(GFP_KERNEL);
543 if (!kbuf)
544 return wrote ? wrote : -ENOMEM;
545 while (count > 0) {
546 unsigned long sz = size_inside_page(p, count);
547 unsigned long n;
548
549 if (!is_vmalloc_or_module_addr((void *)p)) {
550 err = -ENXIO;
551 break;
552 }
553 n = copy_from_user(kbuf, buf, sz);
554 if (n) {
555 err = -EFAULT;
556 break;
557 }
558 vwrite(kbuf, (char *)p, sz);
559 count -= sz;
560 buf += sz;
561 virtr += sz;
562 p += sz;
563 }
564 free_page((unsigned long)kbuf);
565 }
566
567 *ppos = p;
568 return virtr + wrote ? : err;
569}
570#endif
571
572#ifdef CONFIG_DEVPORT
573static ssize_t read_port(struct file *file, char __user *buf,
574 size_t count, loff_t *ppos)
575{
576 unsigned long i = *ppos;
577 char __user *tmp = buf;
578
579 if (!access_ok(VERIFY_WRITE, buf, count))
580 return -EFAULT;
581 while (count-- > 0 && i < 65536) {
582 if (__put_user(inb(i), tmp) < 0)
583 return -EFAULT;
584 i++;
585 tmp++;
586 }
587 *ppos = i;
588 return tmp-buf;
589}
590
591static ssize_t write_port(struct file *file, const char __user *buf,
592 size_t count, loff_t *ppos)
593{
594 unsigned long i = *ppos;
595 const char __user * tmp = buf;
596
597 if (!access_ok(VERIFY_READ, buf, count))
598 return -EFAULT;
599 while (count-- > 0 && i < 65536) {
600 char c;
601 if (__get_user(c, tmp)) {
602 if (tmp > buf)
603 break;
604 return -EFAULT;
605 }
606 outb(c, i);
607 i++;
608 tmp++;
609 }
610 *ppos = i;
611 return tmp-buf;
612}
613#endif
614
615static ssize_t read_null(struct file *file, char __user *buf,
616 size_t count, loff_t *ppos)
617{
618 return 0;
619}
620
621static ssize_t write_null(struct file *file, const char __user *buf,
622 size_t count, loff_t *ppos)
623{
624 return count;
625}
626
627static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
628 struct splice_desc *sd)
629{
630 return sd->len;
631}
632
633static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out,
634 loff_t *ppos, size_t len, unsigned int flags)
635{
636 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
637}
638
639static ssize_t read_zero(struct file *file, char __user *buf,
640 size_t count, loff_t *ppos)
641{
642 size_t written;
643
644 if (!count)
645 return 0;
646
647 if (!access_ok(VERIFY_WRITE, buf, count))
648 return -EFAULT;
649
650 written = 0;
651 while (count) {
652 unsigned long unwritten;
653 size_t chunk = count;
654
655 if (chunk > PAGE_SIZE)
656 chunk = PAGE_SIZE; /* Just for latency reasons */
657 unwritten = __clear_user(buf, chunk);
658 written += chunk - unwritten;
659 if (unwritten)
660 break;
661 if (signal_pending(current))
662 return written ? written : -ERESTARTSYS;
663 buf += chunk;
664 count -= chunk;
665 cond_resched();
666 }
667 return written ? written : -EFAULT;
668}
669
670static int mmap_zero(struct file *file, struct vm_area_struct *vma)
671{
672#ifndef CONFIG_MMU
673 return -ENOSYS;
674#endif
675 if (vma->vm_flags & VM_SHARED)
676 return shmem_zero_setup(vma);
677 return 0;
678}
679
680static ssize_t write_full(struct file *file, const char __user *buf,
681 size_t count, loff_t *ppos)
682{
683 return -ENOSPC;
684}
685
686/*
687 * Special lseek() function for /dev/null and /dev/zero. Most notably, you
688 * can fopen() both devices with "a" now. This was previously impossible.
689 * -- SRB.
690 */
691static loff_t null_lseek(struct file *file, loff_t offset, int orig)
692{
693 return file->f_pos = 0;
694}
695
696/*
697 * The memory devices use the full 32/64 bits of the offset, and so we cannot
698 * check against negative addresses: they are ok. The return value is weird,
699 * though, in that case (0).
700 *
701 * also note that seeking relative to the "end of file" isn't supported:
702 * it has no meaning, so it returns -EINVAL.
703 */
704static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
705{
706 loff_t ret;
707
708 mutex_lock(&file->f_path.dentry->d_inode->i_mutex);
709 switch (orig) {
710 case SEEK_CUR:
711 offset += file->f_pos;
712 case SEEK_SET:
713 /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */
714 if ((unsigned long long)offset >= ~0xFFFULL) {
715 ret = -EOVERFLOW;
716 break;
717 }
718 file->f_pos = offset;
719 ret = file->f_pos;
720 force_successful_syscall_return();
721 break;
722 default:
723 ret = -EINVAL;
724 }
725 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
726 return ret;
727}
728
729static int open_port(struct inode * inode, struct file * filp)
730{
731 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
732}
733
734#define zero_lseek null_lseek
735#define full_lseek null_lseek
736#define write_zero write_null
737#define read_full read_zero
738#define open_mem open_port
739#define open_kmem open_mem
740#define open_oldmem open_mem
741
742static const struct file_operations mem_fops = {
743 .llseek = memory_lseek,
744 .read = read_mem,
745 .write = write_mem,
746 .mmap = mmap_mem,
747 .open = open_mem,
748 .get_unmapped_area = get_unmapped_area_mem,
749};
750
751#ifdef CONFIG_DEVKMEM
752static const struct file_operations kmem_fops = {
753 .llseek = memory_lseek,
754 .read = read_kmem,
755 .write = write_kmem,
756 .mmap = mmap_kmem,
757 .open = open_kmem,
758 .get_unmapped_area = get_unmapped_area_mem,
759};
760#endif
761
762static const struct file_operations null_fops = {
763 .llseek = null_lseek,
764 .read = read_null,
765 .write = write_null,
766 .splice_write = splice_write_null,
767};
768
769#ifdef CONFIG_DEVPORT
770static const struct file_operations port_fops = {
771 .llseek = memory_lseek,
772 .read = read_port,
773 .write = write_port,
774 .open = open_port,
775};
776#endif
777
778static const struct file_operations zero_fops = {
779 .llseek = zero_lseek,
780 .read = read_zero,
781 .write = write_zero,
782 .mmap = mmap_zero,
783};
784
785/*
786 * capabilities for /dev/zero
787 * - permits private mappings, "copies" are taken of the source of zeros
788 * - no writeback happens
789 */
790static struct backing_dev_info zero_bdi = {
791 .name = "char/mem",
792 .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK,
793};
794
795static const struct file_operations full_fops = {
796 .llseek = full_lseek,
797 .read = read_full,
798 .write = write_full,
799};
800
801#ifdef CONFIG_CRASH_DUMP
802static const struct file_operations oldmem_fops = {
803 .read = read_oldmem,
804 .open = open_oldmem,
805 .llseek = default_llseek,
806};
807#endif
808
809static ssize_t kmsg_writev(struct kiocb *iocb, const struct iovec *iv,
810 unsigned long count, loff_t pos)
811{
812 char *line, *p;
813 int i;
814 ssize_t ret = -EFAULT;
815 size_t len = iov_length(iv, count);
816
817 line = kmalloc(len + 1, GFP_KERNEL);
818 if (line == NULL)
819 return -ENOMEM;
820
821 /*
822 * copy all vectors into a single string, to ensure we do
823 * not interleave our log line with other printk calls
824 */
825 p = line;
826 for (i = 0; i < count; i++) {
827 if (copy_from_user(p, iv[i].iov_base, iv[i].iov_len))
828 goto out;
829 p += iv[i].iov_len;
830 }
831 p[0] = '\0';
832
833 ret = printk("%s", line);
834 /* printk can add a prefix */
835 if (ret > len)
836 ret = len;
837out:
838 kfree(line);
839 return ret;
840}
841
842static const struct file_operations kmsg_fops = {
843 .aio_write = kmsg_writev,
844 .llseek = noop_llseek,
845};
846
847static const struct memdev {
848 const char *name;
849 mode_t mode;
850 const struct file_operations *fops;
851 struct backing_dev_info *dev_info;
852} devlist[] = {
853 [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi },
854#ifdef CONFIG_DEVKMEM
855 [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi },
856#endif
857 [3] = { "null", 0666, &null_fops, NULL },
858#ifdef CONFIG_DEVPORT
859 [4] = { "port", 0, &port_fops, NULL },
860#endif
861 [5] = { "zero", 0666, &zero_fops, &zero_bdi },
862 [7] = { "full", 0666, &full_fops, NULL },
863 [8] = { "random", 0666, &random_fops, NULL },
864 [9] = { "urandom", 0666, &urandom_fops, NULL },
865 [11] = { "kmsg", 0, &kmsg_fops, NULL },
866#ifdef CONFIG_CRASH_DUMP
867 [12] = { "oldmem", 0, &oldmem_fops, NULL },
868#endif
869};
870
871static int memory_open(struct inode *inode, struct file *filp)
872{
873 int minor;
874 const struct memdev *dev;
875
876 minor = iminor(inode);
877 if (minor >= ARRAY_SIZE(devlist))
878 return -ENXIO;
879
880 dev = &devlist[minor];
881 if (!dev->fops)
882 return -ENXIO;
883
884 filp->f_op = dev->fops;
885 if (dev->dev_info)
886 filp->f_mapping->backing_dev_info = dev->dev_info;
887
888 /* Is /dev/mem or /dev/kmem ? */
889 if (dev->dev_info == &directly_mappable_cdev_bdi)
890 filp->f_mode |= FMODE_UNSIGNED_OFFSET;
891
892 if (dev->fops->open)
893 return dev->fops->open(inode, filp);
894
895 return 0;
896}
897
898static const struct file_operations memory_fops = {
899 .open = memory_open,
900 .llseek = noop_llseek,
901};
902
903static char *mem_devnode(struct device *dev, mode_t *mode)
904{
905 if (mode && devlist[MINOR(dev->devt)].mode)
906 *mode = devlist[MINOR(dev->devt)].mode;
907 return NULL;
908}
909
910static struct class *mem_class;
911
912static int __init chr_dev_init(void)
913{
914 int minor;
915 int err;
916
917 err = bdi_init(&zero_bdi);
918 if (err)
919 return err;
920
921 if (register_chrdev(MEM_MAJOR, "mem", &memory_fops))
922 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
923
924 mem_class = class_create(THIS_MODULE, "mem");
925 if (IS_ERR(mem_class))
926 return PTR_ERR(mem_class);
927
928 mem_class->devnode = mem_devnode;
929 for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
930 if (!devlist[minor].name)
931 continue;
932 device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
933 NULL, devlist[minor].name);
934 }
935
936 return tty_init();
937}
938
939fs_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/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);