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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
33#include <linux/uaccess.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
100
101
102
103
104static ssize_t read_mem(struct file *file, char __user *buf,
105 size_t count, loff_t *ppos)
106{
107 phys_addr_t p = *ppos;
108 ssize_t read, sz;
109 void *ptr;
110
111 if (p != *ppos)
112 return 0;
113
114 if (!valid_phys_addr_range(p, count))
115 return -EFAULT;
116 read = 0;
117#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
118
119 if (p < PAGE_SIZE) {
120 sz = size_inside_page(p, count);
121 if (sz > 0) {
122 if (clear_user(buf, sz))
123 return -EFAULT;
124 buf += sz;
125 p += sz;
126 count -= sz;
127 read += sz;
128 }
129 }
130#endif
131
132 while (count > 0) {
133 unsigned long remaining;
134 int allowed;
135
136 sz = size_inside_page(p, count);
137
138 allowed = page_is_allowed(p >> PAGE_SHIFT);
139 if (!allowed)
140 return -EPERM;
141 if (allowed == 2) {
142
143 remaining = clear_user(buf, sz);
144 } else {
145
146
147
148
149
150 ptr = xlate_dev_mem_ptr(p);
151 if (!ptr)
152 return -EFAULT;
153
154 remaining = copy_to_user(buf, ptr, sz);
155
156 unxlate_dev_mem_ptr(p, ptr);
157 }
158
159 if (remaining)
160 return -EFAULT;
161
162 buf += sz;
163 p += sz;
164 count -= sz;
165 read += sz;
166 }
167
168 *ppos += read;
169 return read;
170}
171
172static ssize_t write_mem(struct file *file, const char __user *buf,
173 size_t count, loff_t *ppos)
174{
175 phys_addr_t p = *ppos;
176 ssize_t written, sz;
177 unsigned long copied;
178 void *ptr;
179
180 if (p != *ppos)
181 return -EFBIG;
182
183 if (!valid_phys_addr_range(p, count))
184 return -EFAULT;
185
186 written = 0;
187
188#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
189
190 if (p < PAGE_SIZE) {
191 sz = size_inside_page(p, count);
192
193 buf += sz;
194 p += sz;
195 count -= sz;
196 written += sz;
197 }
198#endif
199
200 while (count > 0) {
201 int allowed;
202
203 sz = size_inside_page(p, count);
204
205 allowed = page_is_allowed(p >> PAGE_SHIFT);
206 if (!allowed)
207 return -EPERM;
208
209
210 if (allowed == 1) {
211
212
213
214
215
216 ptr = xlate_dev_mem_ptr(p);
217 if (!ptr) {
218 if (written)
219 break;
220 return -EFAULT;
221 }
222
223 copied = copy_from_user(ptr, buf, sz);
224 unxlate_dev_mem_ptr(p, ptr);
225 if (copied) {
226 written += sz - copied;
227 if (written)
228 break;
229 return -EFAULT;
230 }
231 }
232
233 buf += sz;
234 p += sz;
235 count -= sz;
236 written += sz;
237 }
238
239 *ppos += written;
240 return written;
241}
242
243int __weak phys_mem_access_prot_allowed(struct file *file,
244 unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
245{
246 return 1;
247}
248
249#ifndef __HAVE_PHYS_MEM_ACCESS_PROT
250
251
252
253
254
255
256#ifdef pgprot_noncached
257static int uncached_access(struct file *file, phys_addr_t addr)
258{
259#if defined(CONFIG_IA64)
260
261
262
263
264 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
265#elif defined(CONFIG_MIPS)
266 {
267 extern int __uncached_access(struct file *file,
268 unsigned long addr);
269
270 return __uncached_access(file, addr);
271 }
272#else
273
274
275
276
277
278 if (file->f_flags & O_DSYNC)
279 return 1;
280 return addr >= __pa(high_memory);
281#endif
282}
283#endif
284
285static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
286 unsigned long size, pgprot_t vma_prot)
287{
288#ifdef pgprot_noncached
289 phys_addr_t offset = pfn << PAGE_SHIFT;
290
291 if (uncached_access(file, offset))
292 return pgprot_noncached(vma_prot);
293#endif
294 return vma_prot;
295}
296#endif
297
298#ifndef CONFIG_MMU
299static unsigned long get_unmapped_area_mem(struct file *file,
300 unsigned long addr,
301 unsigned long len,
302 unsigned long pgoff,
303 unsigned long flags)
304{
305 if (!valid_mmap_phys_addr_range(pgoff, len))
306 return (unsigned long) -EINVAL;
307 return pgoff << PAGE_SHIFT;
308}
309
310
311static unsigned memory_mmap_capabilities(struct file *file)
312{
313 return NOMMU_MAP_DIRECT |
314 NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC;
315}
316
317static unsigned zero_mmap_capabilities(struct file *file)
318{
319 return NOMMU_MAP_COPY;
320}
321
322
323static inline int private_mapping_ok(struct vm_area_struct *vma)
324{
325 return vma->vm_flags & VM_MAYSHARE;
326}
327#else
328
329static inline int private_mapping_ok(struct vm_area_struct *vma)
330{
331 return 1;
332}
333#endif
334
335static const struct vm_operations_struct mmap_mem_ops = {
336#ifdef CONFIG_HAVE_IOREMAP_PROT
337 .access = generic_access_phys
338#endif
339};
340
341static int mmap_mem(struct file *file, struct vm_area_struct *vma)
342{
343 size_t size = vma->vm_end - vma->vm_start;
344 phys_addr_t offset = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;
345
346
347 if (offset + (phys_addr_t)size - 1 < offset)
348 return -EINVAL;
349
350 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
351 return -EINVAL;
352
353 if (!private_mapping_ok(vma))
354 return -ENOSYS;
355
356 if (!range_is_allowed(vma->vm_pgoff, size))
357 return -EPERM;
358
359 if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
360 &vma->vm_page_prot))
361 return -EINVAL;
362
363 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
364 size,
365 vma->vm_page_prot);
366
367 vma->vm_ops = &mmap_mem_ops;
368
369
370 if (remap_pfn_range(vma,
371 vma->vm_start,
372 vma->vm_pgoff,
373 size,
374 vma->vm_page_prot)) {
375 return -EAGAIN;
376 }
377 return 0;
378}
379
380static int mmap_kmem(struct file *file, struct vm_area_struct *vma)
381{
382 unsigned long pfn;
383
384
385 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
386
387
388
389
390
391
392
393
394 if (!pfn_valid(pfn))
395 return -EIO;
396
397 vma->vm_pgoff = pfn;
398 return mmap_mem(file, vma);
399}
400
401
402
403
404static ssize_t read_kmem(struct file *file, char __user *buf,
405 size_t count, loff_t *ppos)
406{
407 unsigned long p = *ppos;
408 ssize_t low_count, read, sz;
409 char *kbuf;
410 int err = 0;
411
412 read = 0;
413 if (p < (unsigned long) high_memory) {
414 low_count = count;
415 if (count > (unsigned long)high_memory - p)
416 low_count = (unsigned long)high_memory - p;
417
418#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
419
420 if (p < PAGE_SIZE && low_count > 0) {
421 sz = size_inside_page(p, low_count);
422 if (clear_user(buf, sz))
423 return -EFAULT;
424 buf += sz;
425 p += sz;
426 read += sz;
427 low_count -= sz;
428 count -= sz;
429 }
430#endif
431 while (low_count > 0) {
432 sz = size_inside_page(p, low_count);
433
434
435
436
437
438
439 kbuf = xlate_dev_kmem_ptr((void *)p);
440 if (!virt_addr_valid(kbuf))
441 return -ENXIO;
442
443 if (copy_to_user(buf, kbuf, sz))
444 return -EFAULT;
445 buf += sz;
446 p += sz;
447 read += sz;
448 low_count -= sz;
449 count -= sz;
450 }
451 }
452
453 if (count > 0) {
454 kbuf = (char *)__get_free_page(GFP_KERNEL);
455 if (!kbuf)
456 return -ENOMEM;
457 while (count > 0) {
458 sz = size_inside_page(p, count);
459 if (!is_vmalloc_or_module_addr((void *)p)) {
460 err = -ENXIO;
461 break;
462 }
463 sz = vread(kbuf, (char *)p, sz);
464 if (!sz)
465 break;
466 if (copy_to_user(buf, kbuf, sz)) {
467 err = -EFAULT;
468 break;
469 }
470 count -= sz;
471 buf += sz;
472 read += sz;
473 p += sz;
474 }
475 free_page((unsigned long)kbuf);
476 }
477 *ppos = p;
478 return read ? read : err;
479}
480
481
482static ssize_t do_write_kmem(unsigned long p, const char __user *buf,
483 size_t count, loff_t *ppos)
484{
485 ssize_t written, sz;
486 unsigned long copied;
487
488 written = 0;
489#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
490
491 if (p < PAGE_SIZE) {
492 sz = size_inside_page(p, count);
493
494 buf += sz;
495 p += sz;
496 count -= sz;
497 written += sz;
498 }
499#endif
500
501 while (count > 0) {
502 void *ptr;
503
504 sz = size_inside_page(p, count);
505
506
507
508
509
510
511 ptr = xlate_dev_kmem_ptr((void *)p);
512 if (!virt_addr_valid(ptr))
513 return -ENXIO;
514
515 copied = copy_from_user(ptr, buf, sz);
516 if (copied) {
517 written += sz - copied;
518 if (written)
519 break;
520 return -EFAULT;
521 }
522 buf += sz;
523 p += sz;
524 count -= sz;
525 written += sz;
526 }
527
528 *ppos += written;
529 return written;
530}
531
532
533
534
535static ssize_t write_kmem(struct file *file, const char __user *buf,
536 size_t count, loff_t *ppos)
537{
538 unsigned long p = *ppos;
539 ssize_t wrote = 0;
540 ssize_t virtr = 0;
541 char *kbuf;
542 int err = 0;
543
544 if (p < (unsigned long) high_memory) {
545 unsigned long to_write = min_t(unsigned long, count,
546 (unsigned long)high_memory - p);
547 wrote = do_write_kmem(p, buf, to_write, ppos);
548 if (wrote != to_write)
549 return wrote;
550 p += wrote;
551 buf += wrote;
552 count -= wrote;
553 }
554
555 if (count > 0) {
556 kbuf = (char *)__get_free_page(GFP_KERNEL);
557 if (!kbuf)
558 return wrote ? wrote : -ENOMEM;
559 while (count > 0) {
560 unsigned long sz = size_inside_page(p, count);
561 unsigned long n;
562
563 if (!is_vmalloc_or_module_addr((void *)p)) {
564 err = -ENXIO;
565 break;
566 }
567 n = copy_from_user(kbuf, buf, sz);
568 if (n) {
569 err = -EFAULT;
570 break;
571 }
572 vwrite(kbuf, (char *)p, sz);
573 count -= sz;
574 buf += sz;
575 virtr += sz;
576 p += sz;
577 }
578 free_page((unsigned long)kbuf);
579 }
580
581 *ppos = p;
582 return virtr + wrote ? : err;
583}
584
585static ssize_t read_port(struct file *file, char __user *buf,
586 size_t count, loff_t *ppos)
587{
588 unsigned long i = *ppos;
589 char __user *tmp = buf;
590
591 if (!access_ok(VERIFY_WRITE, buf, count))
592 return -EFAULT;
593 while (count-- > 0 && i < 65536) {
594 if (__put_user(inb(i), tmp) < 0)
595 return -EFAULT;
596 i++;
597 tmp++;
598 }
599 *ppos = i;
600 return tmp-buf;
601}
602
603static ssize_t write_port(struct file *file, const char __user *buf,
604 size_t count, loff_t *ppos)
605{
606 unsigned long i = *ppos;
607 const char __user *tmp = buf;
608
609 if (!access_ok(VERIFY_READ, buf, count))
610 return -EFAULT;
611 while (count-- > 0 && i < 65536) {
612 char c;
613
614 if (__get_user(c, tmp)) {
615 if (tmp > buf)
616 break;
617 return -EFAULT;
618 }
619 outb(c, i);
620 i++;
621 tmp++;
622 }
623 *ppos = i;
624 return tmp-buf;
625}
626
627static ssize_t read_null(struct file *file, char __user *buf,
628 size_t count, loff_t *ppos)
629{
630 return 0;
631}
632
633static ssize_t write_null(struct file *file, const char __user *buf,
634 size_t count, loff_t *ppos)
635{
636 return count;
637}
638
639static ssize_t read_iter_null(struct kiocb *iocb, struct iov_iter *to)
640{
641 return 0;
642}
643
644static ssize_t write_iter_null(struct kiocb *iocb, struct iov_iter *from)
645{
646 size_t count = iov_iter_count(from);
647 iov_iter_advance(from, count);
648 return count;
649}
650
651static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
652 struct splice_desc *sd)
653{
654 return sd->len;
655}
656
657static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out,
658 loff_t *ppos, size_t len, unsigned int flags)
659{
660 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
661}
662
663static ssize_t read_iter_zero(struct kiocb *iocb, struct iov_iter *iter)
664{
665 size_t written = 0;
666
667 while (iov_iter_count(iter)) {
668 size_t chunk = iov_iter_count(iter), n;
669
670 if (chunk > PAGE_SIZE)
671 chunk = PAGE_SIZE;
672 n = iov_iter_zero(chunk, iter);
673 if (!n && iov_iter_count(iter))
674 return written ? written : -EFAULT;
675 written += n;
676 if (signal_pending(current))
677 return written ? written : -ERESTARTSYS;
678 cond_resched();
679 }
680 return written;
681}
682
683static int mmap_zero(struct file *file, struct vm_area_struct *vma)
684{
685#ifndef CONFIG_MMU
686 return -ENOSYS;
687#endif
688 if (vma->vm_flags & VM_SHARED)
689 return shmem_zero_setup(vma);
690 return 0;
691}
692
693static unsigned long get_unmapped_area_zero(struct file *file,
694 unsigned long addr, unsigned long len,
695 unsigned long pgoff, unsigned long flags)
696{
697#ifdef CONFIG_MMU
698 if (flags & MAP_SHARED) {
699
700
701
702
703
704
705 return shmem_get_unmapped_area(NULL, addr, len, pgoff, flags);
706 }
707
708
709 return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
710#else
711 return -ENOSYS;
712#endif
713}
714
715static ssize_t write_full(struct file *file, const char __user *buf,
716 size_t count, loff_t *ppos)
717{
718 return -ENOSPC;
719}
720
721
722
723
724
725
726static loff_t null_lseek(struct file *file, loff_t offset, int orig)
727{
728 return file->f_pos = 0;
729}
730
731
732
733
734
735
736
737
738
739static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
740{
741 loff_t ret;
742
743 inode_lock(file_inode(file));
744 switch (orig) {
745 case SEEK_CUR:
746 offset += file->f_pos;
747 case SEEK_SET:
748
749 if ((unsigned long long)offset >= -MAX_ERRNO) {
750 ret = -EOVERFLOW;
751 break;
752 }
753 file->f_pos = offset;
754 ret = file->f_pos;
755 force_successful_syscall_return();
756 break;
757 default:
758 ret = -EINVAL;
759 }
760 inode_unlock(file_inode(file));
761 return ret;
762}
763
764static int open_port(struct inode *inode, struct file *filp)
765{
766 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
767}
768
769#define zero_lseek null_lseek
770#define full_lseek null_lseek
771#define write_zero write_null
772#define write_iter_zero write_iter_null
773#define open_mem open_port
774#define open_kmem open_mem
775
776static const struct file_operations __maybe_unused mem_fops = {
777 .llseek = memory_lseek,
778 .read = read_mem,
779 .write = write_mem,
780 .mmap = mmap_mem,
781 .open = open_mem,
782#ifndef CONFIG_MMU
783 .get_unmapped_area = get_unmapped_area_mem,
784 .mmap_capabilities = memory_mmap_capabilities,
785#endif
786};
787
788static const struct file_operations __maybe_unused kmem_fops = {
789 .llseek = memory_lseek,
790 .read = read_kmem,
791 .write = write_kmem,
792 .mmap = mmap_kmem,
793 .open = open_kmem,
794#ifndef CONFIG_MMU
795 .get_unmapped_area = get_unmapped_area_mem,
796 .mmap_capabilities = memory_mmap_capabilities,
797#endif
798};
799
800static const struct file_operations null_fops = {
801 .llseek = null_lseek,
802 .read = read_null,
803 .write = write_null,
804 .read_iter = read_iter_null,
805 .write_iter = write_iter_null,
806 .splice_write = splice_write_null,
807};
808
809static const struct file_operations __maybe_unused port_fops = {
810 .llseek = memory_lseek,
811 .read = read_port,
812 .write = write_port,
813 .open = open_port,
814};
815
816static const struct file_operations zero_fops = {
817 .llseek = zero_lseek,
818 .write = write_zero,
819 .read_iter = read_iter_zero,
820 .write_iter = write_iter_zero,
821 .mmap = mmap_zero,
822 .get_unmapped_area = get_unmapped_area_zero,
823#ifndef CONFIG_MMU
824 .mmap_capabilities = zero_mmap_capabilities,
825#endif
826};
827
828static const struct file_operations full_fops = {
829 .llseek = full_lseek,
830 .read_iter = read_iter_zero,
831 .write = write_full,
832};
833
834static const struct memdev {
835 const char *name;
836 umode_t mode;
837 const struct file_operations *fops;
838 fmode_t fmode;
839} devlist[] = {
840#ifdef CONFIG_DEVMEM
841 [1] = { "mem", 0, &mem_fops, FMODE_UNSIGNED_OFFSET },
842#endif
843#ifdef CONFIG_DEVKMEM
844 [2] = { "kmem", 0, &kmem_fops, FMODE_UNSIGNED_OFFSET },
845#endif
846 [3] = { "null", 0666, &null_fops, 0 },
847#ifdef CONFIG_DEVPORT
848 [4] = { "port", 0, &port_fops, 0 },
849#endif
850 [5] = { "zero", 0666, &zero_fops, 0 },
851 [7] = { "full", 0666, &full_fops, 0 },
852 [8] = { "random", 0666, &random_fops, 0 },
853 [9] = { "urandom", 0666, &urandom_fops, 0 },
854#ifdef CONFIG_PRINTK
855 [11] = { "kmsg", 0644, &kmsg_fops, 0 },
856#endif
857};
858
859static int memory_open(struct inode *inode, struct file *filp)
860{
861 int minor;
862 const struct memdev *dev;
863
864 minor = iminor(inode);
865 if (minor >= ARRAY_SIZE(devlist))
866 return -ENXIO;
867
868 dev = &devlist[minor];
869 if (!dev->fops)
870 return -ENXIO;
871
872 filp->f_op = dev->fops;
873 filp->f_mode |= dev->fmode;
874
875 if (dev->fops->open)
876 return dev->fops->open(inode, filp);
877
878 return 0;
879}
880
881static const struct file_operations memory_fops = {
882 .open = memory_open,
883 .llseek = noop_llseek,
884};
885
886static char *mem_devnode(struct device *dev, umode_t *mode)
887{
888 if (mode && devlist[MINOR(dev->devt)].mode)
889 *mode = devlist[MINOR(dev->devt)].mode;
890 return NULL;
891}
892
893static struct class *mem_class;
894
895static int __init chr_dev_init(void)
896{
897 int minor;
898
899 if (register_chrdev(MEM_MAJOR, "mem", &memory_fops))
900 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
901
902 mem_class = class_create(THIS_MODULE, "mem");
903 if (IS_ERR(mem_class))
904 return PTR_ERR(mem_class);
905
906 mem_class->devnode = mem_devnode;
907 for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
908 if (!devlist[minor].name)
909 continue;
910
911
912
913
914 if ((minor == DEVPORT_MINOR) && !arch_has_dev_port())
915 continue;
916
917 device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
918 NULL, devlist[minor].name);
919 }
920
921 return tty_init();
922}
923
924fs_initcall(chr_dev_init);
925