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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
93
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
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
133
134
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
173 if (p < PAGE_SIZE) {
174 sz = size_inside_page(p, count);
175
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
191
192
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
230
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
239
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
252
253
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
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
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
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
357 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
358
359
360
361
362
363
364
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
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;
382 int err = 0;
383
384 if (!pfn_valid(PFN_DOWN(p)))
385 return -EIO;
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
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
411
412
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
464 if (p < PAGE_SIZE) {
465 sz = size_inside_page(p, count);
466
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
481
482
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
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;
513 int err = 0;
514
515 if (!pfn_valid(PFN_DOWN(p)))
516 return -EIO;
517
518 if (p < (unsigned long) high_memory) {
519 unsigned long to_write = min_t(unsigned long, count,
520 (unsigned long)high_memory - p);
521 wrote = do_write_kmem(p, buf, to_write, ppos);
522 if (wrote != to_write)
523 return wrote;
524 p += wrote;
525 buf += wrote;
526 count -= wrote;
527 }
528
529 if (count > 0) {
530 kbuf = (char *)__get_free_page(GFP_KERNEL);
531 if (!kbuf)
532 return wrote ? wrote : -ENOMEM;
533 while (count > 0) {
534 unsigned long sz = size_inside_page(p, count);
535 unsigned long n;
536
537 if (!is_vmalloc_or_module_addr((void *)p)) {
538 err = -ENXIO;
539 break;
540 }
541 n = copy_from_user(kbuf, buf, sz);
542 if (n) {
543 err = -EFAULT;
544 break;
545 }
546 vwrite(kbuf, (char *)p, sz);
547 count -= sz;
548 buf += sz;
549 virtr += sz;
550 p += sz;
551 }
552 free_page((unsigned long)kbuf);
553 }
554
555 *ppos = p;
556 return virtr + wrote ? : err;
557}
558
559static ssize_t read_port(struct file *file, char __user *buf,
560 size_t count, loff_t *ppos)
561{
562 unsigned long i = *ppos;
563 char __user *tmp = buf;
564
565 if (!access_ok(VERIFY_WRITE, buf, count))
566 return -EFAULT;
567 while (count-- > 0 && i < 65536) {
568 if (__put_user(inb(i), tmp) < 0)
569 return -EFAULT;
570 i++;
571 tmp++;
572 }
573 *ppos = i;
574 return tmp-buf;
575}
576
577static ssize_t write_port(struct file *file, const char __user *buf,
578 size_t count, loff_t *ppos)
579{
580 unsigned long i = *ppos;
581 const char __user *tmp = buf;
582
583 if (!access_ok(VERIFY_READ, buf, count))
584 return -EFAULT;
585 while (count-- > 0 && i < 65536) {
586 char c;
587
588 if (__get_user(c, tmp)) {
589 if (tmp > buf)
590 break;
591 return -EFAULT;
592 }
593 outb(c, i);
594 i++;
595 tmp++;
596 }
597 *ppos = i;
598 return tmp-buf;
599}
600
601static ssize_t read_null(struct file *file, char __user *buf,
602 size_t count, loff_t *ppos)
603{
604 return 0;
605}
606
607static ssize_t write_null(struct file *file, const char __user *buf,
608 size_t count, loff_t *ppos)
609{
610 return count;
611}
612
613static ssize_t read_iter_null(struct kiocb *iocb, struct iov_iter *to)
614{
615 return 0;
616}
617
618static ssize_t write_iter_null(struct kiocb *iocb, struct iov_iter *from)
619{
620 size_t count = iov_iter_count(from);
621 iov_iter_advance(from, count);
622 return count;
623}
624
625static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
626 struct splice_desc *sd)
627{
628 return sd->len;
629}
630
631static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out,
632 loff_t *ppos, size_t len, unsigned int flags)
633{
634 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
635}
636
637static ssize_t read_iter_zero(struct kiocb *iocb, struct iov_iter *iter)
638{
639 size_t written = 0;
640
641 while (iov_iter_count(iter)) {
642 size_t chunk = iov_iter_count(iter), n;
643
644 if (chunk > PAGE_SIZE)
645 chunk = PAGE_SIZE;
646 n = iov_iter_zero(chunk, iter);
647 if (!n && iov_iter_count(iter))
648 return written ? written : -EFAULT;
649 written += n;
650 if (signal_pending(current))
651 return written ? written : -ERESTARTSYS;
652 cond_resched();
653 }
654 return written;
655}
656
657static int mmap_zero(struct file *file, struct vm_area_struct *vma)
658{
659#ifndef CONFIG_MMU
660 return -ENOSYS;
661#endif
662 if (vma->vm_flags & VM_SHARED)
663 return shmem_zero_setup(vma);
664 return 0;
665}
666
667static unsigned long get_unmapped_area_zero(struct file *file,
668 unsigned long addr, unsigned long len,
669 unsigned long pgoff, unsigned long flags)
670{
671#ifdef CONFIG_MMU
672 if (flags & MAP_SHARED) {
673
674
675
676
677
678
679 return shmem_get_unmapped_area(NULL, addr, len, pgoff, flags);
680 }
681
682
683 return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
684#else
685 return -ENOSYS;
686#endif
687}
688
689static ssize_t write_full(struct file *file, const char __user *buf,
690 size_t count, loff_t *ppos)
691{
692 return -ENOSPC;
693}
694
695
696
697
698
699
700static loff_t null_lseek(struct file *file, loff_t offset, int orig)
701{
702 return file->f_pos = 0;
703}
704
705
706
707
708
709
710
711
712
713static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
714{
715 loff_t ret;
716
717 inode_lock(file_inode(file));
718 switch (orig) {
719 case SEEK_CUR:
720 offset += file->f_pos;
721 case SEEK_SET:
722
723 if ((unsigned long long)offset >= -MAX_ERRNO) {
724 ret = -EOVERFLOW;
725 break;
726 }
727 file->f_pos = offset;
728 ret = file->f_pos;
729 force_successful_syscall_return();
730 break;
731 default:
732 ret = -EINVAL;
733 }
734 inode_unlock(file_inode(file));
735 return ret;
736}
737
738static int open_port(struct inode *inode, struct file *filp)
739{
740 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
741}
742
743#define zero_lseek null_lseek
744#define full_lseek null_lseek
745#define write_zero write_null
746#define write_iter_zero write_iter_null
747#define open_mem open_port
748#define open_kmem open_mem
749
750static const struct file_operations __maybe_unused mem_fops = {
751 .llseek = memory_lseek,
752 .read = read_mem,
753 .write = write_mem,
754 .mmap = mmap_mem,
755 .open = open_mem,
756#ifndef CONFIG_MMU
757 .get_unmapped_area = get_unmapped_area_mem,
758 .mmap_capabilities = memory_mmap_capabilities,
759#endif
760};
761
762static const struct file_operations __maybe_unused kmem_fops = {
763 .llseek = memory_lseek,
764 .read = read_kmem,
765 .write = write_kmem,
766 .mmap = mmap_kmem,
767 .open = open_kmem,
768#ifndef CONFIG_MMU
769 .get_unmapped_area = get_unmapped_area_mem,
770 .mmap_capabilities = memory_mmap_capabilities,
771#endif
772};
773
774static const struct file_operations null_fops = {
775 .llseek = null_lseek,
776 .read = read_null,
777 .write = write_null,
778 .read_iter = read_iter_null,
779 .write_iter = write_iter_null,
780 .splice_write = splice_write_null,
781};
782
783static const struct file_operations __maybe_unused port_fops = {
784 .llseek = memory_lseek,
785 .read = read_port,
786 .write = write_port,
787 .open = open_port,
788};
789
790static const struct file_operations zero_fops = {
791 .llseek = zero_lseek,
792 .write = write_zero,
793 .read_iter = read_iter_zero,
794 .write_iter = write_iter_zero,
795 .mmap = mmap_zero,
796 .get_unmapped_area = get_unmapped_area_zero,
797#ifndef CONFIG_MMU
798 .mmap_capabilities = zero_mmap_capabilities,
799#endif
800};
801
802static const struct file_operations full_fops = {
803 .llseek = full_lseek,
804 .read_iter = read_iter_zero,
805 .write = write_full,
806};
807
808static const struct memdev {
809 const char *name;
810 umode_t mode;
811 const struct file_operations *fops;
812 fmode_t fmode;
813} devlist[] = {
814#ifdef CONFIG_DEVMEM
815 [1] = { "mem", 0, &mem_fops, FMODE_UNSIGNED_OFFSET },
816#endif
817#ifdef CONFIG_DEVKMEM
818 [2] = { "kmem", 0, &kmem_fops, FMODE_UNSIGNED_OFFSET },
819#endif
820 [3] = { "null", 0666, &null_fops, 0 },
821#ifdef CONFIG_DEVPORT
822 [4] = { "port", 0, &port_fops, 0 },
823#endif
824 [5] = { "zero", 0666, &zero_fops, 0 },
825 [7] = { "full", 0666, &full_fops, 0 },
826 [8] = { "random", 0666, &random_fops, 0 },
827 [9] = { "urandom", 0666, &urandom_fops, 0 },
828#ifdef CONFIG_PRINTK
829 [11] = { "kmsg", 0644, &kmsg_fops, 0 },
830#endif
831};
832
833static int memory_open(struct inode *inode, struct file *filp)
834{
835 int minor;
836 const struct memdev *dev;
837
838 minor = iminor(inode);
839 if (minor >= ARRAY_SIZE(devlist))
840 return -ENXIO;
841
842 dev = &devlist[minor];
843 if (!dev->fops)
844 return -ENXIO;
845
846 filp->f_op = dev->fops;
847 filp->f_mode |= dev->fmode;
848
849 if (dev->fops->open)
850 return dev->fops->open(inode, filp);
851
852 return 0;
853}
854
855static const struct file_operations memory_fops = {
856 .open = memory_open,
857 .llseek = noop_llseek,
858};
859
860static char *mem_devnode(struct device *dev, umode_t *mode)
861{
862 if (mode && devlist[MINOR(dev->devt)].mode)
863 *mode = devlist[MINOR(dev->devt)].mode;
864 return NULL;
865}
866
867static struct class *mem_class;
868
869static int __init chr_dev_init(void)
870{
871 int minor;
872
873 if (register_chrdev(MEM_MAJOR, "mem", &memory_fops))
874 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
875
876 mem_class = class_create(THIS_MODULE, "mem");
877 if (IS_ERR(mem_class))
878 return PTR_ERR(mem_class);
879
880 mem_class->devnode = mem_devnode;
881 for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
882 if (!devlist[minor].name)
883 continue;
884
885
886
887
888 if ((minor == DEVPORT_MINOR) && !arch_has_dev_port())
889 continue;
890
891 device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
892 NULL, devlist[minor].name);
893 }
894
895 return tty_init();
896}
897
898fs_initcall(chr_dev_init);
899