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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/drivers/char/mem.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 *
7 * Added devfs support.
8 * Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu>
9 * Shared /dev/zero mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com>
10 */
11
12#include <linux/mm.h>
13#include <linux/miscdevice.h>
14#include <linux/slab.h>
15#include <linux/vmalloc.h>
16#include <linux/mman.h>
17#include <linux/random.h>
18#include <linux/init.h>
19#include <linux/raw.h>
20#include <linux/tty.h>
21#include <linux/capability.h>
22#include <linux/ptrace.h>
23#include <linux/device.h>
24#include <linux/highmem.h>
25#include <linux/backing-dev.h>
26#include <linux/shmem_fs.h>
27#include <linux/splice.h>
28#include <linux/pfn.h>
29#include <linux/export.h>
30#include <linux/io.h>
31#include <linux/uio.h>
32#include <linux/uaccess.h>
33#include <linux/security.h>
34
35#ifdef CONFIG_IA64
36# include <linux/efi.h>
37#endif
38
39#define DEVPORT_MINOR 4
40
41static inline unsigned long size_inside_page(unsigned long start,
42 unsigned long size)
43{
44 unsigned long sz;
45
46 sz = PAGE_SIZE - (start & (PAGE_SIZE - 1));
47
48 return min(sz, size);
49}
50
51#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
52static inline int valid_phys_addr_range(phys_addr_t addr, size_t count)
53{
54 return addr + count <= __pa(high_memory);
55}
56
57static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
58{
59 return 1;
60}
61#endif
62
63#ifdef CONFIG_STRICT_DEVMEM
64static inline int page_is_allowed(unsigned long pfn)
65{
66 return devmem_is_allowed(pfn);
67}
68static inline int range_is_allowed(unsigned long pfn, unsigned long size)
69{
70 u64 from = ((u64)pfn) << PAGE_SHIFT;
71 u64 to = from + size;
72 u64 cursor = from;
73
74 while (cursor < to) {
75 if (!devmem_is_allowed(pfn))
76 return 0;
77 cursor += PAGE_SIZE;
78 pfn++;
79 }
80 return 1;
81}
82#else
83static inline int page_is_allowed(unsigned long pfn)
84{
85 return 1;
86}
87static inline int range_is_allowed(unsigned long pfn, unsigned long size)
88{
89 return 1;
90}
91#endif
92
93#ifndef unxlate_dev_mem_ptr
94#define unxlate_dev_mem_ptr unxlate_dev_mem_ptr
95void __weak unxlate_dev_mem_ptr(phys_addr_t phys, void *addr)
96{
97}
98#endif
99
100static inline bool should_stop_iteration(void)
101{
102 if (need_resched())
103 cond_resched();
104 return fatal_signal_pending(current);
105}
106
107/*
108 * This funcion reads the *physical* memory. The f_pos points directly to the
109 * memory location.
110 */
111static ssize_t read_mem(struct file *file, char __user *buf,
112 size_t count, loff_t *ppos)
113{
114 phys_addr_t p = *ppos;
115 ssize_t read, sz;
116 void *ptr;
117 char *bounce;
118 int err;
119
120 if (p != *ppos)
121 return 0;
122
123 if (!valid_phys_addr_range(p, count))
124 return -EFAULT;
125 read = 0;
126#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
127 /* we don't have page 0 mapped on sparc and m68k.. */
128 if (p < PAGE_SIZE) {
129 sz = size_inside_page(p, count);
130 if (sz > 0) {
131 if (clear_user(buf, sz))
132 return -EFAULT;
133 buf += sz;
134 p += sz;
135 count -= sz;
136 read += sz;
137 }
138 }
139#endif
140
141 bounce = kmalloc(PAGE_SIZE, GFP_KERNEL);
142 if (!bounce)
143 return -ENOMEM;
144
145 while (count > 0) {
146 unsigned long remaining;
147 int allowed, probe;
148
149 sz = size_inside_page(p, count);
150
151 err = -EPERM;
152 allowed = page_is_allowed(p >> PAGE_SHIFT);
153 if (!allowed)
154 goto failed;
155
156 err = -EFAULT;
157 if (allowed == 2) {
158 /* Show zeros for restricted memory. */
159 remaining = clear_user(buf, sz);
160 } else {
161 /*
162 * On ia64 if a page has been mapped somewhere as
163 * uncached, then it must also be accessed uncached
164 * by the kernel or data corruption may occur.
165 */
166 ptr = xlate_dev_mem_ptr(p);
167 if (!ptr)
168 goto failed;
169
170 probe = probe_kernel_read(bounce, ptr, sz);
171 unxlate_dev_mem_ptr(p, ptr);
172 if (probe)
173 goto failed;
174
175 remaining = copy_to_user(buf, bounce, sz);
176 }
177
178 if (remaining)
179 goto failed;
180
181 buf += sz;
182 p += sz;
183 count -= sz;
184 read += sz;
185 if (should_stop_iteration())
186 break;
187 }
188 kfree(bounce);
189
190 *ppos += read;
191 return read;
192
193failed:
194 kfree(bounce);
195 return err;
196}
197
198static ssize_t write_mem(struct file *file, const char __user *buf,
199 size_t count, loff_t *ppos)
200{
201 phys_addr_t p = *ppos;
202 ssize_t written, sz;
203 unsigned long copied;
204 void *ptr;
205
206 if (p != *ppos)
207 return -EFBIG;
208
209 if (!valid_phys_addr_range(p, count))
210 return -EFAULT;
211
212 written = 0;
213
214#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
215 /* we don't have page 0 mapped on sparc and m68k.. */
216 if (p < PAGE_SIZE) {
217 sz = size_inside_page(p, count);
218 /* Hmm. Do something? */
219 buf += sz;
220 p += sz;
221 count -= sz;
222 written += sz;
223 }
224#endif
225
226 while (count > 0) {
227 int allowed;
228
229 sz = size_inside_page(p, count);
230
231 allowed = page_is_allowed(p >> PAGE_SHIFT);
232 if (!allowed)
233 return -EPERM;
234
235 /* Skip actual writing when a page is marked as restricted. */
236 if (allowed == 1) {
237 /*
238 * On ia64 if a page has been mapped somewhere as
239 * uncached, then it must also be accessed uncached
240 * by the kernel or data corruption may occur.
241 */
242 ptr = xlate_dev_mem_ptr(p);
243 if (!ptr) {
244 if (written)
245 break;
246 return -EFAULT;
247 }
248
249 copied = copy_from_user(ptr, buf, sz);
250 unxlate_dev_mem_ptr(p, ptr);
251 if (copied) {
252 written += sz - copied;
253 if (written)
254 break;
255 return -EFAULT;
256 }
257 }
258
259 buf += sz;
260 p += sz;
261 count -= sz;
262 written += sz;
263 if (should_stop_iteration())
264 break;
265 }
266
267 *ppos += written;
268 return written;
269}
270
271int __weak phys_mem_access_prot_allowed(struct file *file,
272 unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
273{
274 return 1;
275}
276
277#ifndef __HAVE_PHYS_MEM_ACCESS_PROT
278
279/*
280 * Architectures vary in how they handle caching for addresses
281 * outside of main memory.
282 *
283 */
284#ifdef pgprot_noncached
285static int uncached_access(struct file *file, phys_addr_t addr)
286{
287#if defined(CONFIG_IA64)
288 /*
289 * On ia64, we ignore O_DSYNC because we cannot tolerate memory
290 * attribute aliases.
291 */
292 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
293#elif defined(CONFIG_MIPS)
294 {
295 extern int __uncached_access(struct file *file,
296 unsigned long addr);
297
298 return __uncached_access(file, addr);
299 }
300#else
301 /*
302 * Accessing memory above the top the kernel knows about or through a
303 * file pointer
304 * that was marked O_DSYNC will be done non-cached.
305 */
306 if (file->f_flags & O_DSYNC)
307 return 1;
308 return addr >= __pa(high_memory);
309#endif
310}
311#endif
312
313static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
314 unsigned long size, pgprot_t vma_prot)
315{
316#ifdef pgprot_noncached
317 phys_addr_t offset = pfn << PAGE_SHIFT;
318
319 if (uncached_access(file, offset))
320 return pgprot_noncached(vma_prot);
321#endif
322 return vma_prot;
323}
324#endif
325
326#ifndef CONFIG_MMU
327static unsigned long get_unmapped_area_mem(struct file *file,
328 unsigned long addr,
329 unsigned long len,
330 unsigned long pgoff,
331 unsigned long flags)
332{
333 if (!valid_mmap_phys_addr_range(pgoff, len))
334 return (unsigned long) -EINVAL;
335 return pgoff << PAGE_SHIFT;
336}
337
338/* permit direct mmap, for read, write or exec */
339static unsigned memory_mmap_capabilities(struct file *file)
340{
341 return NOMMU_MAP_DIRECT |
342 NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC;
343}
344
345static unsigned zero_mmap_capabilities(struct file *file)
346{
347 return NOMMU_MAP_COPY;
348}
349
350/* can't do an in-place private mapping if there's no MMU */
351static inline int private_mapping_ok(struct vm_area_struct *vma)
352{
353 return vma->vm_flags & VM_MAYSHARE;
354}
355#else
356
357static inline int private_mapping_ok(struct vm_area_struct *vma)
358{
359 return 1;
360}
361#endif
362
363static const struct vm_operations_struct mmap_mem_ops = {
364#ifdef CONFIG_HAVE_IOREMAP_PROT
365 .access = generic_access_phys
366#endif
367};
368
369static int mmap_mem(struct file *file, struct vm_area_struct *vma)
370{
371 size_t size = vma->vm_end - vma->vm_start;
372 phys_addr_t offset = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;
373
374 /* Does it even fit in phys_addr_t? */
375 if (offset >> PAGE_SHIFT != vma->vm_pgoff)
376 return -EINVAL;
377
378 /* It's illegal to wrap around the end of the physical address space. */
379 if (offset + (phys_addr_t)size - 1 < offset)
380 return -EINVAL;
381
382 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
383 return -EINVAL;
384
385 if (!private_mapping_ok(vma))
386 return -ENOSYS;
387
388 if (!range_is_allowed(vma->vm_pgoff, size))
389 return -EPERM;
390
391 if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
392 &vma->vm_page_prot))
393 return -EINVAL;
394
395 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
396 size,
397 vma->vm_page_prot);
398
399 vma->vm_ops = &mmap_mem_ops;
400
401 /* Remap-pfn-range will mark the range VM_IO */
402 if (remap_pfn_range(vma,
403 vma->vm_start,
404 vma->vm_pgoff,
405 size,
406 vma->vm_page_prot)) {
407 return -EAGAIN;
408 }
409 return 0;
410}
411
412static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
413{
414 unsigned long pfn;
415
416 /* Turn a kernel-virtual address into a physical page frame */
417 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
418
419 /*
420 * RED-PEN: on some architectures there is more mapped memory than
421 * available in mem_map which pfn_valid checks for. Perhaps should add a
422 * new macro here.
423 *
424 * RED-PEN: vmalloc is not supported right now.
425 */
426 if (!pfn_valid(pfn))
427 return -EIO;
428
429 vma->vm_pgoff = pfn;
430 return mmap_mem(file, vma);
431}
432
433/*
434 * This function reads the *virtual* memory as seen by the kernel.
435 */
436static ssize_t read_kmem(struct file *file, char __user *buf,
437 size_t count, loff_t *ppos)
438{
439 unsigned long p = *ppos;
440 ssize_t low_count, read, sz;
441 char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
442 int err = 0;
443
444 read = 0;
445 if (p < (unsigned long) high_memory) {
446 low_count = count;
447 if (count > (unsigned long)high_memory - p)
448 low_count = (unsigned long)high_memory - p;
449
450#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
451 /* we don't have page 0 mapped on sparc and m68k.. */
452 if (p < PAGE_SIZE && low_count > 0) {
453 sz = size_inside_page(p, low_count);
454 if (clear_user(buf, sz))
455 return -EFAULT;
456 buf += sz;
457 p += sz;
458 read += sz;
459 low_count -= sz;
460 count -= sz;
461 }
462#endif
463 while (low_count > 0) {
464 sz = size_inside_page(p, low_count);
465
466 /*
467 * On ia64 if a page has been mapped somewhere as
468 * uncached, then it must also be accessed uncached
469 * by the kernel or data corruption may occur
470 */
471 kbuf = xlate_dev_kmem_ptr((void *)p);
472 if (!virt_addr_valid(kbuf))
473 return -ENXIO;
474
475 if (copy_to_user(buf, kbuf, sz))
476 return -EFAULT;
477 buf += sz;
478 p += sz;
479 read += sz;
480 low_count -= sz;
481 count -= sz;
482 if (should_stop_iteration()) {
483 count = 0;
484 break;
485 }
486 }
487 }
488
489 if (count > 0) {
490 kbuf = (char *)__get_free_page(GFP_KERNEL);
491 if (!kbuf)
492 return -ENOMEM;
493 while (count > 0) {
494 sz = size_inside_page(p, count);
495 if (!is_vmalloc_or_module_addr((void *)p)) {
496 err = -ENXIO;
497 break;
498 }
499 sz = vread(kbuf, (char *)p, sz);
500 if (!sz)
501 break;
502 if (copy_to_user(buf, kbuf, sz)) {
503 err = -EFAULT;
504 break;
505 }
506 count -= sz;
507 buf += sz;
508 read += sz;
509 p += sz;
510 if (should_stop_iteration())
511 break;
512 }
513 free_page((unsigned long)kbuf);
514 }
515 *ppos = p;
516 return read ? read : err;
517}
518
519
520static ssize_t do_write_kmem(unsigned long p, const char __user *buf,
521 size_t count, loff_t *ppos)
522{
523 ssize_t written, sz;
524 unsigned long copied;
525
526 written = 0;
527#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
528 /* we don't have page 0 mapped on sparc and m68k.. */
529 if (p < PAGE_SIZE) {
530 sz = size_inside_page(p, count);
531 /* Hmm. Do something? */
532 buf += sz;
533 p += sz;
534 count -= sz;
535 written += sz;
536 }
537#endif
538
539 while (count > 0) {
540 void *ptr;
541
542 sz = size_inside_page(p, count);
543
544 /*
545 * On ia64 if a page has been mapped somewhere as uncached, then
546 * it must also be accessed uncached by the kernel or data
547 * corruption may occur.
548 */
549 ptr = xlate_dev_kmem_ptr((void *)p);
550 if (!virt_addr_valid(ptr))
551 return -ENXIO;
552
553 copied = copy_from_user(ptr, buf, sz);
554 if (copied) {
555 written += sz - copied;
556 if (written)
557 break;
558 return -EFAULT;
559 }
560 buf += sz;
561 p += sz;
562 count -= sz;
563 written += sz;
564 if (should_stop_iteration())
565 break;
566 }
567
568 *ppos += written;
569 return written;
570}
571
572/*
573 * This function writes to the *virtual* memory as seen by the kernel.
574 */
575static ssize_t write_kmem(struct file *file, const char __user *buf,
576 size_t count, loff_t *ppos)
577{
578 unsigned long p = *ppos;
579 ssize_t wrote = 0;
580 ssize_t virtr = 0;
581 char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
582 int err = 0;
583
584 if (p < (unsigned long) high_memory) {
585 unsigned long to_write = min_t(unsigned long, count,
586 (unsigned long)high_memory - p);
587 wrote = do_write_kmem(p, buf, to_write, ppos);
588 if (wrote != to_write)
589 return wrote;
590 p += wrote;
591 buf += wrote;
592 count -= wrote;
593 }
594
595 if (count > 0) {
596 kbuf = (char *)__get_free_page(GFP_KERNEL);
597 if (!kbuf)
598 return wrote ? wrote : -ENOMEM;
599 while (count > 0) {
600 unsigned long sz = size_inside_page(p, count);
601 unsigned long n;
602
603 if (!is_vmalloc_or_module_addr((void *)p)) {
604 err = -ENXIO;
605 break;
606 }
607 n = copy_from_user(kbuf, buf, sz);
608 if (n) {
609 err = -EFAULT;
610 break;
611 }
612 vwrite(kbuf, (char *)p, sz);
613 count -= sz;
614 buf += sz;
615 virtr += sz;
616 p += sz;
617 if (should_stop_iteration())
618 break;
619 }
620 free_page((unsigned long)kbuf);
621 }
622
623 *ppos = p;
624 return virtr + wrote ? : err;
625}
626
627static ssize_t read_port(struct file *file, char __user *buf,
628 size_t count, loff_t *ppos)
629{
630 unsigned long i = *ppos;
631 char __user *tmp = buf;
632
633 if (!access_ok(buf, count))
634 return -EFAULT;
635 while (count-- > 0 && i < 65536) {
636 if (__put_user(inb(i), tmp) < 0)
637 return -EFAULT;
638 i++;
639 tmp++;
640 }
641 *ppos = i;
642 return tmp-buf;
643}
644
645static ssize_t write_port(struct file *file, const char __user *buf,
646 size_t count, loff_t *ppos)
647{
648 unsigned long i = *ppos;
649 const char __user *tmp = buf;
650
651 if (!access_ok(buf, count))
652 return -EFAULT;
653 while (count-- > 0 && i < 65536) {
654 char c;
655
656 if (__get_user(c, tmp)) {
657 if (tmp > buf)
658 break;
659 return -EFAULT;
660 }
661 outb(c, i);
662 i++;
663 tmp++;
664 }
665 *ppos = i;
666 return tmp-buf;
667}
668
669static ssize_t read_null(struct file *file, char __user *buf,
670 size_t count, loff_t *ppos)
671{
672 return 0;
673}
674
675static ssize_t write_null(struct file *file, const char __user *buf,
676 size_t count, loff_t *ppos)
677{
678 return count;
679}
680
681static ssize_t read_iter_null(struct kiocb *iocb, struct iov_iter *to)
682{
683 return 0;
684}
685
686static ssize_t write_iter_null(struct kiocb *iocb, struct iov_iter *from)
687{
688 size_t count = iov_iter_count(from);
689 iov_iter_advance(from, count);
690 return count;
691}
692
693static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
694 struct splice_desc *sd)
695{
696 return sd->len;
697}
698
699static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out,
700 loff_t *ppos, size_t len, unsigned int flags)
701{
702 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
703}
704
705static ssize_t read_iter_zero(struct kiocb *iocb, struct iov_iter *iter)
706{
707 size_t written = 0;
708
709 while (iov_iter_count(iter)) {
710 size_t chunk = iov_iter_count(iter), n;
711
712 if (chunk > PAGE_SIZE)
713 chunk = PAGE_SIZE; /* Just for latency reasons */
714 n = iov_iter_zero(chunk, iter);
715 if (!n && iov_iter_count(iter))
716 return written ? written : -EFAULT;
717 written += n;
718 if (signal_pending(current))
719 return written ? written : -ERESTARTSYS;
720 cond_resched();
721 }
722 return written;
723}
724
725static int mmap_zero(struct file *file, struct vm_area_struct *vma)
726{
727#ifndef CONFIG_MMU
728 return -ENOSYS;
729#endif
730 if (vma->vm_flags & VM_SHARED)
731 return shmem_zero_setup(vma);
732 vma_set_anonymous(vma);
733 return 0;
734}
735
736static unsigned long get_unmapped_area_zero(struct file *file,
737 unsigned long addr, unsigned long len,
738 unsigned long pgoff, unsigned long flags)
739{
740#ifdef CONFIG_MMU
741 if (flags & MAP_SHARED) {
742 /*
743 * mmap_zero() will call shmem_zero_setup() to create a file,
744 * so use shmem's get_unmapped_area in case it can be huge;
745 * and pass NULL for file as in mmap.c's get_unmapped_area(),
746 * so as not to confuse shmem with our handle on "/dev/zero".
747 */
748 return shmem_get_unmapped_area(NULL, addr, len, pgoff, flags);
749 }
750
751 /* Otherwise flags & MAP_PRIVATE: with no shmem object beneath it */
752 return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
753#else
754 return -ENOSYS;
755#endif
756}
757
758static ssize_t write_full(struct file *file, const char __user *buf,
759 size_t count, loff_t *ppos)
760{
761 return -ENOSPC;
762}
763
764/*
765 * Special lseek() function for /dev/null and /dev/zero. Most notably, you
766 * can fopen() both devices with "a" now. This was previously impossible.
767 * -- SRB.
768 */
769static loff_t null_lseek(struct file *file, loff_t offset, int orig)
770{
771 return file->f_pos = 0;
772}
773
774/*
775 * The memory devices use the full 32/64 bits of the offset, and so we cannot
776 * check against negative addresses: they are ok. The return value is weird,
777 * though, in that case (0).
778 *
779 * also note that seeking relative to the "end of file" isn't supported:
780 * it has no meaning, so it returns -EINVAL.
781 */
782static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
783{
784 loff_t ret;
785
786 inode_lock(file_inode(file));
787 switch (orig) {
788 case SEEK_CUR:
789 offset += file->f_pos;
790 /* fall through */
791 case SEEK_SET:
792 /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */
793 if ((unsigned long long)offset >= -MAX_ERRNO) {
794 ret = -EOVERFLOW;
795 break;
796 }
797 file->f_pos = offset;
798 ret = file->f_pos;
799 force_successful_syscall_return();
800 break;
801 default:
802 ret = -EINVAL;
803 }
804 inode_unlock(file_inode(file));
805 return ret;
806}
807
808static int open_port(struct inode *inode, struct file *filp)
809{
810 if (!capable(CAP_SYS_RAWIO))
811 return -EPERM;
812
813 return security_locked_down(LOCKDOWN_DEV_MEM);
814}
815
816#define zero_lseek null_lseek
817#define full_lseek null_lseek
818#define write_zero write_null
819#define write_iter_zero write_iter_null
820#define open_mem open_port
821#define open_kmem open_mem
822
823static const struct file_operations __maybe_unused mem_fops = {
824 .llseek = memory_lseek,
825 .read = read_mem,
826 .write = write_mem,
827 .mmap = mmap_mem,
828 .open = open_mem,
829#ifndef CONFIG_MMU
830 .get_unmapped_area = get_unmapped_area_mem,
831 .mmap_capabilities = memory_mmap_capabilities,
832#endif
833};
834
835static const struct file_operations __maybe_unused kmem_fops = {
836 .llseek = memory_lseek,
837 .read = read_kmem,
838 .write = write_kmem,
839 .mmap = mmap_kmem,
840 .open = open_kmem,
841#ifndef CONFIG_MMU
842 .get_unmapped_area = get_unmapped_area_mem,
843 .mmap_capabilities = memory_mmap_capabilities,
844#endif
845};
846
847static const struct file_operations null_fops = {
848 .llseek = null_lseek,
849 .read = read_null,
850 .write = write_null,
851 .read_iter = read_iter_null,
852 .write_iter = write_iter_null,
853 .splice_write = splice_write_null,
854};
855
856static const struct file_operations __maybe_unused port_fops = {
857 .llseek = memory_lseek,
858 .read = read_port,
859 .write = write_port,
860 .open = open_port,
861};
862
863static const struct file_operations zero_fops = {
864 .llseek = zero_lseek,
865 .write = write_zero,
866 .read_iter = read_iter_zero,
867 .write_iter = write_iter_zero,
868 .mmap = mmap_zero,
869 .get_unmapped_area = get_unmapped_area_zero,
870#ifndef CONFIG_MMU
871 .mmap_capabilities = zero_mmap_capabilities,
872#endif
873};
874
875static const struct file_operations full_fops = {
876 .llseek = full_lseek,
877 .read_iter = read_iter_zero,
878 .write = write_full,
879};
880
881static const struct memdev {
882 const char *name;
883 umode_t mode;
884 const struct file_operations *fops;
885 fmode_t fmode;
886} devlist[] = {
887#ifdef CONFIG_DEVMEM
888 [1] = { "mem", 0, &mem_fops, FMODE_UNSIGNED_OFFSET },
889#endif
890#ifdef CONFIG_DEVKMEM
891 [2] = { "kmem", 0, &kmem_fops, FMODE_UNSIGNED_OFFSET },
892#endif
893 [3] = { "null", 0666, &null_fops, 0 },
894#ifdef CONFIG_DEVPORT
895 [4] = { "port", 0, &port_fops, 0 },
896#endif
897 [5] = { "zero", 0666, &zero_fops, 0 },
898 [7] = { "full", 0666, &full_fops, 0 },
899 [8] = { "random", 0666, &random_fops, 0 },
900 [9] = { "urandom", 0666, &urandom_fops, 0 },
901#ifdef CONFIG_PRINTK
902 [11] = { "kmsg", 0644, &kmsg_fops, 0 },
903#endif
904};
905
906static int memory_open(struct inode *inode, struct file *filp)
907{
908 int minor;
909 const struct memdev *dev;
910
911 minor = iminor(inode);
912 if (minor >= ARRAY_SIZE(devlist))
913 return -ENXIO;
914
915 dev = &devlist[minor];
916 if (!dev->fops)
917 return -ENXIO;
918
919 filp->f_op = dev->fops;
920 filp->f_mode |= dev->fmode;
921
922 if (dev->fops->open)
923 return dev->fops->open(inode, filp);
924
925 return 0;
926}
927
928static const struct file_operations memory_fops = {
929 .open = memory_open,
930 .llseek = noop_llseek,
931};
932
933static char *mem_devnode(struct device *dev, umode_t *mode)
934{
935 if (mode && devlist[MINOR(dev->devt)].mode)
936 *mode = devlist[MINOR(dev->devt)].mode;
937 return NULL;
938}
939
940static struct class *mem_class;
941
942static int __init chr_dev_init(void)
943{
944 int minor;
945
946 if (register_chrdev(MEM_MAJOR, "mem", &memory_fops))
947 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
948
949 mem_class = class_create(THIS_MODULE, "mem");
950 if (IS_ERR(mem_class))
951 return PTR_ERR(mem_class);
952
953 mem_class->devnode = mem_devnode;
954 for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
955 if (!devlist[minor].name)
956 continue;
957
958 /*
959 * Create /dev/port?
960 */
961 if ((minor == DEVPORT_MINOR) && !arch_has_dev_port())
962 continue;
963
964 device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
965 NULL, devlist[minor].name);
966 }
967
968 return tty_init();
969}
970
971fs_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);