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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/char/mem.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'drivers/char/mem.c')
-rw-r--r--drivers/char/mem.c880
1 files changed, 880 insertions, 0 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
new file mode 100644
index 000000000000..947cb3cef816
--- /dev/null
+++ b/drivers/char/mem.c
@@ -0,0 +1,880 @@
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 mmaping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com>
9 */
10
11#include <linux/config.h>
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/smp_lock.h>
23#include <linux/devfs_fs_kernel.h>
24#include <linux/ptrace.h>
25#include <linux/device.h>
26#include <linux/backing-dev.h>
27
28#include <asm/uaccess.h>
29#include <asm/io.h>
30
31#ifdef CONFIG_IA64
32# include <linux/efi.h>
33#endif
34
35#if defined(CONFIG_S390_TAPE) && defined(CONFIG_S390_TAPE_CHAR)
36extern void tapechar_init(void);
37#endif
38
39/*
40 * Architectures vary in how they handle caching for addresses
41 * outside of main memory.
42 *
43 */
44static inline int uncached_access(struct file *file, unsigned long addr)
45{
46#if defined(__i386__)
47 /*
48 * On the PPro and successors, the MTRRs are used to set
49 * memory types for physical addresses outside main memory,
50 * so blindly setting PCD or PWT on those pages is wrong.
51 * For Pentiums and earlier, the surround logic should disable
52 * caching for the high addresses through the KEN pin, but
53 * we maintain the tradition of paranoia in this code.
54 */
55 if (file->f_flags & O_SYNC)
56 return 1;
57 return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) ||
58 test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) ||
59 test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) ||
60 test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) )
61 && addr >= __pa(high_memory);
62#elif defined(__x86_64__)
63 /*
64 * This is broken because it can generate memory type aliases,
65 * which can cause cache corruptions
66 * But it is only available for root and we have to be bug-to-bug
67 * compatible with i386.
68 */
69 if (file->f_flags & O_SYNC)
70 return 1;
71 /* same behaviour as i386. PAT always set to cached and MTRRs control the
72 caching behaviour.
73 Hopefully a full PAT implementation will fix that soon. */
74 return 0;
75#elif defined(CONFIG_IA64)
76 /*
77 * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
78 */
79 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
80#else
81 /*
82 * Accessing memory above the top the kernel knows about or through a file pointer
83 * that was marked O_SYNC will be done non-cached.
84 */
85 if (file->f_flags & O_SYNC)
86 return 1;
87 return addr >= __pa(high_memory);
88#endif
89}
90
91#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
92static inline int valid_phys_addr_range(unsigned long addr, size_t *count)
93{
94 unsigned long end_mem;
95
96 end_mem = __pa(high_memory);
97 if (addr >= end_mem)
98 return 0;
99
100 if (*count > end_mem - addr)
101 *count = end_mem - addr;
102
103 return 1;
104}
105#endif
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 unsigned long p = *ppos;
115 ssize_t read, sz;
116 char *ptr;
117
118 if (!valid_phys_addr_range(p, &count))
119 return -EFAULT;
120 read = 0;
121#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
122 /* we don't have page 0 mapped on sparc and m68k.. */
123 if (p < PAGE_SIZE) {
124 sz = PAGE_SIZE - p;
125 if (sz > count)
126 sz = count;
127 if (sz > 0) {
128 if (clear_user(buf, sz))
129 return -EFAULT;
130 buf += sz;
131 p += sz;
132 count -= sz;
133 read += sz;
134 }
135 }
136#endif
137
138 while (count > 0) {
139 /*
140 * Handle first page in case it's not aligned
141 */
142 if (-p & (PAGE_SIZE - 1))
143 sz = -p & (PAGE_SIZE - 1);
144 else
145 sz = PAGE_SIZE;
146
147 sz = min_t(unsigned long, sz, count);
148
149 /*
150 * On ia64 if a page has been mapped somewhere as
151 * uncached, then it must also be accessed uncached
152 * by the kernel or data corruption may occur
153 */
154 ptr = xlate_dev_mem_ptr(p);
155
156 if (copy_to_user(buf, ptr, sz))
157 return -EFAULT;
158 buf += sz;
159 p += sz;
160 count -= sz;
161 read += sz;
162 }
163
164 *ppos += read;
165 return read;
166}
167
168static ssize_t write_mem(struct file * file, const char __user * buf,
169 size_t count, loff_t *ppos)
170{
171 unsigned long p = *ppos;
172 ssize_t written, sz;
173 unsigned long copied;
174 void *ptr;
175
176 if (!valid_phys_addr_range(p, &count))
177 return -EFAULT;
178
179 written = 0;
180
181#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
182 /* we don't have page 0 mapped on sparc and m68k.. */
183 if (p < PAGE_SIZE) {
184 unsigned long sz = PAGE_SIZE - p;
185 if (sz > count)
186 sz = count;
187 /* Hmm. Do something? */
188 buf += sz;
189 p += sz;
190 count -= sz;
191 written += sz;
192 }
193#endif
194
195 while (count > 0) {
196 /*
197 * Handle first page in case it's not aligned
198 */
199 if (-p & (PAGE_SIZE - 1))
200 sz = -p & (PAGE_SIZE - 1);
201 else
202 sz = PAGE_SIZE;
203
204 sz = min_t(unsigned long, sz, count);
205
206 /*
207 * On ia64 if a page has been mapped somewhere as
208 * uncached, then it must also be accessed uncached
209 * by the kernel or data corruption may occur
210 */
211 ptr = xlate_dev_mem_ptr(p);
212
213 copied = copy_from_user(ptr, buf, sz);
214 if (copied) {
215 ssize_t ret;
216
217 ret = written + (sz - copied);
218 if (ret)
219 return ret;
220 return -EFAULT;
221 }
222 buf += sz;
223 p += sz;
224 count -= sz;
225 written += sz;
226 }
227
228 *ppos += written;
229 return written;
230}
231
232static int mmap_mem(struct file * file, struct vm_area_struct * vma)
233{
234#if defined(__HAVE_PHYS_MEM_ACCESS_PROT)
235 unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
236
237 vma->vm_page_prot = phys_mem_access_prot(file, offset,
238 vma->vm_end - vma->vm_start,
239 vma->vm_page_prot);
240#elif defined(pgprot_noncached)
241 unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
242 int uncached;
243
244 uncached = uncached_access(file, offset);
245 if (uncached)
246 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
247#endif
248
249 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
250 if (remap_pfn_range(vma,
251 vma->vm_start,
252 vma->vm_pgoff,
253 vma->vm_end-vma->vm_start,
254 vma->vm_page_prot))
255 return -EAGAIN;
256 return 0;
257}
258
259static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
260{
261 unsigned long long val;
262 /*
263 * RED-PEN: on some architectures there is more mapped memory
264 * than available in mem_map which pfn_valid checks
265 * for. Perhaps should add a new macro here.
266 *
267 * RED-PEN: vmalloc is not supported right now.
268 */
269 if (!pfn_valid(vma->vm_pgoff))
270 return -EIO;
271 val = (u64)vma->vm_pgoff << PAGE_SHIFT;
272 vma->vm_pgoff = __pa(val) >> PAGE_SHIFT;
273 return mmap_mem(file, vma);
274}
275
276extern long vread(char *buf, char *addr, unsigned long count);
277extern long vwrite(char *buf, char *addr, unsigned long count);
278
279/*
280 * This function reads the *virtual* memory as seen by the kernel.
281 */
282static ssize_t read_kmem(struct file *file, char __user *buf,
283 size_t count, loff_t *ppos)
284{
285 unsigned long p = *ppos;
286 ssize_t low_count, read, sz;
287 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
288
289 read = 0;
290 if (p < (unsigned long) high_memory) {
291 low_count = count;
292 if (count > (unsigned long) high_memory - p)
293 low_count = (unsigned long) high_memory - p;
294
295#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
296 /* we don't have page 0 mapped on sparc and m68k.. */
297 if (p < PAGE_SIZE && low_count > 0) {
298 size_t tmp = PAGE_SIZE - p;
299 if (tmp > low_count) tmp = low_count;
300 if (clear_user(buf, tmp))
301 return -EFAULT;
302 buf += tmp;
303 p += tmp;
304 read += tmp;
305 low_count -= tmp;
306 count -= tmp;
307 }
308#endif
309 while (low_count > 0) {
310 /*
311 * Handle first page in case it's not aligned
312 */
313 if (-p & (PAGE_SIZE - 1))
314 sz = -p & (PAGE_SIZE - 1);
315 else
316 sz = PAGE_SIZE;
317
318 sz = min_t(unsigned long, sz, low_count);
319
320 /*
321 * On ia64 if a page has been mapped somewhere as
322 * uncached, then it must also be accessed uncached
323 * by the kernel or data corruption may occur
324 */
325 kbuf = xlate_dev_kmem_ptr((char *)p);
326
327 if (copy_to_user(buf, kbuf, sz))
328 return -EFAULT;
329 buf += sz;
330 p += sz;
331 read += sz;
332 low_count -= sz;
333 count -= sz;
334 }
335 }
336
337 if (count > 0) {
338 kbuf = (char *)__get_free_page(GFP_KERNEL);
339 if (!kbuf)
340 return -ENOMEM;
341 while (count > 0) {
342 int len = count;
343
344 if (len > PAGE_SIZE)
345 len = PAGE_SIZE;
346 len = vread(kbuf, (char *)p, len);
347 if (!len)
348 break;
349 if (copy_to_user(buf, kbuf, len)) {
350 free_page((unsigned long)kbuf);
351 return -EFAULT;
352 }
353 count -= len;
354 buf += len;
355 read += len;
356 p += len;
357 }
358 free_page((unsigned long)kbuf);
359 }
360 *ppos = p;
361 return read;
362}
363
364
365static inline ssize_t
366do_write_kmem(void *p, unsigned long realp, const char __user * buf,
367 size_t count, loff_t *ppos)
368{
369 ssize_t written, sz;
370 unsigned long copied;
371
372 written = 0;
373#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
374 /* we don't have page 0 mapped on sparc and m68k.. */
375 if (realp < PAGE_SIZE) {
376 unsigned long sz = PAGE_SIZE - realp;
377 if (sz > count)
378 sz = count;
379 /* Hmm. Do something? */
380 buf += sz;
381 p += sz;
382 realp += sz;
383 count -= sz;
384 written += sz;
385 }
386#endif
387
388 while (count > 0) {
389 char *ptr;
390 /*
391 * Handle first page in case it's not aligned
392 */
393 if (-realp & (PAGE_SIZE - 1))
394 sz = -realp & (PAGE_SIZE - 1);
395 else
396 sz = PAGE_SIZE;
397
398 sz = min_t(unsigned long, sz, count);
399
400 /*
401 * On ia64 if a page has been mapped somewhere as
402 * uncached, then it must also be accessed uncached
403 * by the kernel or data corruption may occur
404 */
405 ptr = xlate_dev_kmem_ptr(p);
406
407 copied = copy_from_user(ptr, buf, sz);
408 if (copied) {
409 ssize_t ret;
410
411 ret = written + (sz - copied);
412 if (ret)
413 return ret;
414 return -EFAULT;
415 }
416 buf += sz;
417 p += sz;
418 realp += sz;
419 count -= sz;
420 written += sz;
421 }
422
423 *ppos += written;
424 return written;
425}
426
427
428/*
429 * This function writes to the *virtual* memory as seen by the kernel.
430 */
431static ssize_t write_kmem(struct file * file, const char __user * buf,
432 size_t count, loff_t *ppos)
433{
434 unsigned long p = *ppos;
435 ssize_t wrote = 0;
436 ssize_t virtr = 0;
437 ssize_t written;
438 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
439
440 if (p < (unsigned long) high_memory) {
441
442 wrote = count;
443 if (count > (unsigned long) high_memory - p)
444 wrote = (unsigned long) high_memory - p;
445
446 written = do_write_kmem((void*)p, p, buf, wrote, ppos);
447 if (written != wrote)
448 return written;
449 wrote = written;
450 p += wrote;
451 buf += wrote;
452 count -= wrote;
453 }
454
455 if (count > 0) {
456 kbuf = (char *)__get_free_page(GFP_KERNEL);
457 if (!kbuf)
458 return wrote ? wrote : -ENOMEM;
459 while (count > 0) {
460 int len = count;
461
462 if (len > PAGE_SIZE)
463 len = PAGE_SIZE;
464 if (len) {
465 written = copy_from_user(kbuf, buf, len);
466 if (written) {
467 ssize_t ret;
468
469 free_page((unsigned long)kbuf);
470 ret = wrote + virtr + (len - written);
471 return ret ? ret : -EFAULT;
472 }
473 }
474 len = vwrite(kbuf, (char *)p, len);
475 count -= len;
476 buf += len;
477 virtr += len;
478 p += len;
479 }
480 free_page((unsigned long)kbuf);
481 }
482
483 *ppos = p;
484 return virtr + wrote;
485}
486
487#if defined(CONFIG_ISA) || !defined(__mc68000__)
488static ssize_t read_port(struct file * file, char __user * buf,
489 size_t count, loff_t *ppos)
490{
491 unsigned long i = *ppos;
492 char __user *tmp = buf;
493
494 if (!access_ok(VERIFY_WRITE, buf, count))
495 return -EFAULT;
496 while (count-- > 0 && i < 65536) {
497 if (__put_user(inb(i),tmp) < 0)
498 return -EFAULT;
499 i++;
500 tmp++;
501 }
502 *ppos = i;
503 return tmp-buf;
504}
505
506static ssize_t write_port(struct file * file, const char __user * buf,
507 size_t count, loff_t *ppos)
508{
509 unsigned long i = *ppos;
510 const char __user * tmp = buf;
511
512 if (!access_ok(VERIFY_READ,buf,count))
513 return -EFAULT;
514 while (count-- > 0 && i < 65536) {
515 char c;
516 if (__get_user(c, tmp))
517 return -EFAULT;
518 outb(c,i);
519 i++;
520 tmp++;
521 }
522 *ppos = i;
523 return tmp-buf;
524}
525#endif
526
527static ssize_t read_null(struct file * file, char __user * buf,
528 size_t count, loff_t *ppos)
529{
530 return 0;
531}
532
533static ssize_t write_null(struct file * file, const char __user * buf,
534 size_t count, loff_t *ppos)
535{
536 return count;
537}
538
539#ifdef CONFIG_MMU
540/*
541 * For fun, we are using the MMU for this.
542 */
543static inline size_t read_zero_pagealigned(char __user * buf, size_t size)
544{
545 struct mm_struct *mm;
546 struct vm_area_struct * vma;
547 unsigned long addr=(unsigned long)buf;
548
549 mm = current->mm;
550 /* Oops, this was forgotten before. -ben */
551 down_read(&mm->mmap_sem);
552
553 /* For private mappings, just map in zero pages. */
554 for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
555 unsigned long count;
556
557 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0)
558 goto out_up;
559 if (vma->vm_flags & (VM_SHARED | VM_HUGETLB))
560 break;
561 count = vma->vm_end - addr;
562 if (count > size)
563 count = size;
564
565 zap_page_range(vma, addr, count, NULL);
566 zeromap_page_range(vma, addr, count, PAGE_COPY);
567
568 size -= count;
569 buf += count;
570 addr += count;
571 if (size == 0)
572 goto out_up;
573 }
574
575 up_read(&mm->mmap_sem);
576
577 /* The shared case is hard. Let's do the conventional zeroing. */
578 do {
579 unsigned long unwritten = clear_user(buf, PAGE_SIZE);
580 if (unwritten)
581 return size + unwritten - PAGE_SIZE;
582 cond_resched();
583 buf += PAGE_SIZE;
584 size -= PAGE_SIZE;
585 } while (size);
586
587 return size;
588out_up:
589 up_read(&mm->mmap_sem);
590 return size;
591}
592
593static ssize_t read_zero(struct file * file, char __user * buf,
594 size_t count, loff_t *ppos)
595{
596 unsigned long left, unwritten, written = 0;
597
598 if (!count)
599 return 0;
600
601 if (!access_ok(VERIFY_WRITE, buf, count))
602 return -EFAULT;
603
604 left = count;
605
606 /* do we want to be clever? Arbitrary cut-off */
607 if (count >= PAGE_SIZE*4) {
608 unsigned long partial;
609
610 /* How much left of the page? */
611 partial = (PAGE_SIZE-1) & -(unsigned long) buf;
612 unwritten = clear_user(buf, partial);
613 written = partial - unwritten;
614 if (unwritten)
615 goto out;
616 left -= partial;
617 buf += partial;
618 unwritten = read_zero_pagealigned(buf, left & PAGE_MASK);
619 written += (left & PAGE_MASK) - unwritten;
620 if (unwritten)
621 goto out;
622 buf += left & PAGE_MASK;
623 left &= ~PAGE_MASK;
624 }
625 unwritten = clear_user(buf, left);
626 written += left - unwritten;
627out:
628 return written ? written : -EFAULT;
629}
630
631static int mmap_zero(struct file * file, struct vm_area_struct * vma)
632{
633 if (vma->vm_flags & VM_SHARED)
634 return shmem_zero_setup(vma);
635 if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot))
636 return -EAGAIN;
637 return 0;
638}
639#else /* CONFIG_MMU */
640static ssize_t read_zero(struct file * file, char * buf,
641 size_t count, loff_t *ppos)
642{
643 size_t todo = count;
644
645 while (todo) {
646 size_t chunk = todo;
647
648 if (chunk > 4096)
649 chunk = 4096; /* Just for latency reasons */
650 if (clear_user(buf, chunk))
651 return -EFAULT;
652 buf += chunk;
653 todo -= chunk;
654 cond_resched();
655 }
656 return count;
657}
658
659static int mmap_zero(struct file * file, struct vm_area_struct * vma)
660{
661 return -ENOSYS;
662}
663#endif /* CONFIG_MMU */
664
665static ssize_t write_full(struct file * file, const char __user * buf,
666 size_t count, loff_t *ppos)
667{
668 return -ENOSPC;
669}
670
671/*
672 * Special lseek() function for /dev/null and /dev/zero. Most notably, you
673 * can fopen() both devices with "a" now. This was previously impossible.
674 * -- SRB.
675 */
676
677static loff_t null_lseek(struct file * file, loff_t offset, int orig)
678{
679 return file->f_pos = 0;
680}
681
682/*
683 * The memory devices use the full 32/64 bits of the offset, and so we cannot
684 * check against negative addresses: they are ok. The return value is weird,
685 * though, in that case (0).
686 *
687 * also note that seeking relative to the "end of file" isn't supported:
688 * it has no meaning, so it returns -EINVAL.
689 */
690static loff_t memory_lseek(struct file * file, loff_t offset, int orig)
691{
692 loff_t ret;
693
694 down(&file->f_dentry->d_inode->i_sem);
695 switch (orig) {
696 case 0:
697 file->f_pos = offset;
698 ret = file->f_pos;
699 force_successful_syscall_return();
700 break;
701 case 1:
702 file->f_pos += offset;
703 ret = file->f_pos;
704 force_successful_syscall_return();
705 break;
706 default:
707 ret = -EINVAL;
708 }
709 up(&file->f_dentry->d_inode->i_sem);
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 read_full read_zero
722#define open_mem open_port
723#define open_kmem open_mem
724
725static struct file_operations mem_fops = {
726 .llseek = memory_lseek,
727 .read = read_mem,
728 .write = write_mem,
729 .mmap = mmap_mem,
730 .open = open_mem,
731};
732
733static struct file_operations kmem_fops = {
734 .llseek = memory_lseek,
735 .read = read_kmem,
736 .write = write_kmem,
737 .mmap = mmap_kmem,
738 .open = open_kmem,
739};
740
741static struct file_operations null_fops = {
742 .llseek = null_lseek,
743 .read = read_null,
744 .write = write_null,
745};
746
747#if defined(CONFIG_ISA) || !defined(__mc68000__)
748static struct file_operations port_fops = {
749 .llseek = memory_lseek,
750 .read = read_port,
751 .write = write_port,
752 .open = open_port,
753};
754#endif
755
756static struct file_operations zero_fops = {
757 .llseek = zero_lseek,
758 .read = read_zero,
759 .write = write_zero,
760 .mmap = mmap_zero,
761};
762
763static struct backing_dev_info zero_bdi = {
764 .capabilities = BDI_CAP_MAP_COPY,
765};
766
767static struct file_operations full_fops = {
768 .llseek = full_lseek,
769 .read = read_full,
770 .write = write_full,
771};
772
773static ssize_t kmsg_write(struct file * file, const char __user * buf,
774 size_t count, loff_t *ppos)
775{
776 char *tmp;
777 int ret;
778
779 tmp = kmalloc(count + 1, GFP_KERNEL);
780 if (tmp == NULL)
781 return -ENOMEM;
782 ret = -EFAULT;
783 if (!copy_from_user(tmp, buf, count)) {
784 tmp[count] = 0;
785 ret = printk("%s", tmp);
786 }
787 kfree(tmp);
788 return ret;
789}
790
791static struct file_operations kmsg_fops = {
792 .write = kmsg_write,
793};
794
795static int memory_open(struct inode * inode, struct file * filp)
796{
797 switch (iminor(inode)) {
798 case 1:
799 filp->f_op = &mem_fops;
800 break;
801 case 2:
802 filp->f_op = &kmem_fops;
803 break;
804 case 3:
805 filp->f_op = &null_fops;
806 break;
807#if defined(CONFIG_ISA) || !defined(__mc68000__)
808 case 4:
809 filp->f_op = &port_fops;
810 break;
811#endif
812 case 5:
813 filp->f_mapping->backing_dev_info = &zero_bdi;
814 filp->f_op = &zero_fops;
815 break;
816 case 7:
817 filp->f_op = &full_fops;
818 break;
819 case 8:
820 filp->f_op = &random_fops;
821 break;
822 case 9:
823 filp->f_op = &urandom_fops;
824 break;
825 case 11:
826 filp->f_op = &kmsg_fops;
827 break;
828 default:
829 return -ENXIO;
830 }
831 if (filp->f_op && filp->f_op->open)
832 return filp->f_op->open(inode,filp);
833 return 0;
834}
835
836static struct file_operations memory_fops = {
837 .open = memory_open, /* just a selector for the real open */
838};
839
840static const struct {
841 unsigned int minor;
842 char *name;
843 umode_t mode;
844 struct file_operations *fops;
845} devlist[] = { /* list of minor devices */
846 {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
847 {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops},
848 {3, "null", S_IRUGO | S_IWUGO, &null_fops},
849#if defined(CONFIG_ISA) || !defined(__mc68000__)
850 {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops},
851#endif
852 {5, "zero", S_IRUGO | S_IWUGO, &zero_fops},
853 {7, "full", S_IRUGO | S_IWUGO, &full_fops},
854 {8, "random", S_IRUGO | S_IWUSR, &random_fops},
855 {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops},
856 {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops},
857};
858
859static struct class_simple *mem_class;
860
861static int __init chr_dev_init(void)
862{
863 int i;
864
865 if (register_chrdev(MEM_MAJOR,"mem",&memory_fops))
866 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
867
868 mem_class = class_simple_create(THIS_MODULE, "mem");
869 for (i = 0; i < ARRAY_SIZE(devlist); i++) {
870 class_simple_device_add(mem_class,
871 MKDEV(MEM_MAJOR, devlist[i].minor),
872 NULL, devlist[i].name);
873 devfs_mk_cdev(MKDEV(MEM_MAJOR, devlist[i].minor),
874 S_IFCHR | devlist[i].mode, devlist[i].name);
875 }
876
877 return 0;
878}
879
880fs_initcall(chr_dev_init);
generated by cgit v1.2.2 (git 2.25.0) at 2025-10-25 12:31:40 -0400