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[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / char / mem.c
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1da177e4
LT		 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>
50b1fdbd
VG		 26#include <linux/highmem.h>
27#include <linux/crash_dump.h>
1da177e4 28#include <linux/backing-dev.h>
315c215c 29#include <linux/bootmem.h>
1da177e4
LT		 30
31#include <asm/uaccess.h>
32#include <asm/io.h>
33
34#ifdef CONFIG_IA64
35# include <linux/efi.h>
36#endif
37
38#if defined(CONFIG_S390_TAPE) && defined(CONFIG_S390_TAPE_CHAR)
39extern void tapechar_init(void);
40#endif
41
42/*
43 * Architectures vary in how they handle caching for addresses
44 * outside of main memory.
45 *
46 */
47static inline int uncached_access(struct file *file, unsigned long addr)
48{
49#if defined(__i386__)
50 /*
51 * On the PPro and successors, the MTRRs are used to set
52 * memory types for physical addresses outside main memory,
53 * so blindly setting PCD or PWT on those pages is wrong.
54 * For Pentiums and earlier, the surround logic should disable
55 * caching for the high addresses through the KEN pin, but
56 * we maintain the tradition of paranoia in this code.
57 */
58 if (file->f_flags & O_SYNC)
59 return 1;
60 return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) ||
61 test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) ||
62 test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) ||
63 test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) )
64 && addr >= __pa(high_memory);
65#elif defined(__x86_64__)
66 /*
67 * This is broken because it can generate memory type aliases,
68 * which can cause cache corruptions
69 * But it is only available for root and we have to be bug-to-bug
70 * compatible with i386.
71 */
72 if (file->f_flags & O_SYNC)
73 return 1;
74 /* same behaviour as i386. PAT always set to cached and MTRRs control the
75 caching behaviour.
76 Hopefully a full PAT implementation will fix that soon. */
77 return 0;
78#elif defined(CONFIG_IA64)
79 /*
80 * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
81 */
82 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
83#else
84 /*
85 * Accessing memory above the top the kernel knows about or through a file pointer
86 * that was marked O_SYNC will be done non-cached.
87 */
88 if (file->f_flags & O_SYNC)
89 return 1;
90 return addr >= __pa(high_memory);
91#endif
92}
93
94#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
95static inline int valid_phys_addr_range(unsigned long addr, size_t *count)
96{
97 unsigned long end_mem;
98
99 end_mem = __pa(high_memory);
100 if (addr >= end_mem)
101 return 0;
102
103 if (*count > end_mem - addr)
104 *count = end_mem - addr;
105
106 return 1;
107}
108#endif
109
110/*
111 * This funcion reads the *physical* memory. The f_pos points directly to the
112 * memory location.
113 */
114static ssize_t read_mem(struct file * file, char __user * buf,
115 size_t count, loff_t *ppos)
116{
117 unsigned long p = *ppos;
118 ssize_t read, sz;
119 char *ptr;
120
121 if (!valid_phys_addr_range(p, &count))
122 return -EFAULT;
123 read = 0;
124#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
125 /* we don't have page 0 mapped on sparc and m68k.. */
126 if (p < PAGE_SIZE) {
127 sz = PAGE_SIZE - p;
128 if (sz > count)
129 sz = 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 while (count > 0) {
142 /*
143 * Handle first page in case it's not aligned
144 */
145 if (-p & (PAGE_SIZE - 1))
146 sz = -p & (PAGE_SIZE - 1);
147 else
148 sz = PAGE_SIZE;
149
150 sz = min_t(unsigned long, sz, count);
151
152 /*
153 * On ia64 if a page has been mapped somewhere as
154 * uncached, then it must also be accessed uncached
155 * by the kernel or data corruption may occur
156 */
157 ptr = xlate_dev_mem_ptr(p);
158
159 if (copy_to_user(buf, ptr, sz))
160 return -EFAULT;
161 buf += sz;
162 p += sz;
163 count -= sz;
164 read += sz;
165 }
166
167 *ppos += read;
168 return read;
169}
170
171static ssize_t write_mem(struct file * file, const char __user * buf,
172 size_t count, loff_t *ppos)
173{
174 unsigned long p = *ppos;
175 ssize_t written, sz;
176 unsigned long copied;
177 void *ptr;
178
179 if (!valid_phys_addr_range(p, &count))
180 return -EFAULT;
181
182 written = 0;
183
184#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
185 /* we don't have page 0 mapped on sparc and m68k.. */
186 if (p < PAGE_SIZE) {
187 unsigned long sz = PAGE_SIZE - p;
188 if (sz > count)
189 sz = count;
190 /* Hmm. Do something? */
191 buf += sz;
192 p += sz;
193 count -= sz;
194 written += sz;
195 }
196#endif
197
198 while (count > 0) {
199 /*
200 * Handle first page in case it's not aligned
201 */
202 if (-p & (PAGE_SIZE - 1))
203 sz = -p & (PAGE_SIZE - 1);
204 else
205 sz = PAGE_SIZE;
206
207 sz = min_t(unsigned long, sz, count);
208
209 /*
210 * On ia64 if a page has been mapped somewhere as
211 * uncached, then it must also be accessed uncached
212 * by the kernel or data corruption may occur
213 */
214 ptr = xlate_dev_mem_ptr(p);
215
216 copied = copy_from_user(ptr, buf, sz);
217 if (copied) {
218 ssize_t ret;
219
220 ret = written + (sz - copied);
221 if (ret)
222 return ret;
223 return -EFAULT;
224 }
225 buf += sz;
226 p += sz;
227 count -= sz;
228 written += sz;
229 }
230
231 *ppos += written;
232 return written;
233}
234
235static int mmap_mem(struct file * file, struct vm_area_struct * vma)
236{
237#if defined(__HAVE_PHYS_MEM_ACCESS_PROT)
238 unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
239
240 vma->vm_page_prot = phys_mem_access_prot(file, offset,
241 vma->vm_end - vma->vm_start,
242 vma->vm_page_prot);
243#elif defined(pgprot_noncached)
244 unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
245 int uncached;
246
247 uncached = uncached_access(file, offset);
248 if (uncached)
249 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
250#endif
251
252 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
253 if (remap_pfn_range(vma,
254 vma->vm_start,
255 vma->vm_pgoff,
256 vma->vm_end-vma->vm_start,
257 vma->vm_page_prot))
258 return -EAGAIN;
259 return 0;
260}
261
262static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
263{
264 unsigned long long val;
265 /*
266 * RED-PEN: on some architectures there is more mapped memory
267 * than available in mem_map which pfn_valid checks
268 * for. Perhaps should add a new macro here.
269 *
270 * RED-PEN: vmalloc is not supported right now.
271 */
272 if (!pfn_valid(vma->vm_pgoff))
273 return -EIO;
274 val = (u64)vma->vm_pgoff << PAGE_SHIFT;
275 vma->vm_pgoff = __pa(val) >> PAGE_SHIFT;
276 return mmap_mem(file, vma);
277}
278
50b1fdbd
VG		 279#ifdef CONFIG_CRASH_DUMP
280/*
281 * Read memory corresponding to the old kernel.
50b1fdbd 282 */
315c215c 283static ssize_t read_oldmem(struct file *file, char __user *buf,
50b1fdbd
VG		 284 size_t count, loff_t *ppos)
285{
315c215c
VG		 286 unsigned long pfn, offset;
287 size_t read = 0, csize;
288 int rc = 0;
50b1fdbd
VG		 289
290 while(count) {
291 pfn = *ppos / PAGE_SIZE;
315c215c
VG		 292 if (pfn > saved_max_pfn)
293 return read;
50b1fdbd 294
315c215c
VG		 295 offset = (unsigned long)(*ppos % PAGE_SIZE);
296 if (count > PAGE_SIZE - offset)
297 csize = PAGE_SIZE - offset;
298 else
299 csize = count;
50b1fdbd 300
315c215c
VG		 301 rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
302 if (rc < 0)
303 return rc;
50b1fdbd
VG		 304 buf += csize;
305 *ppos += csize;
306 read += csize;
307 count -= csize;
308 }
50b1fdbd
VG		 309 return read;
310}
311#endif
312
1da177e4
LT		 313extern long vread(char *buf, char *addr, unsigned long count);
314extern long vwrite(char *buf, char *addr, unsigned long count);
315
316/*
317 * This function reads the *virtual* memory as seen by the kernel.
318 */
319static ssize_t read_kmem(struct file *file, char __user *buf,
320 size_t count, loff_t *ppos)
321{
322 unsigned long p = *ppos;
323 ssize_t low_count, read, sz;
324 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
325
326 read = 0;
327 if (p < (unsigned long) high_memory) {
328 low_count = count;
329 if (count > (unsigned long) high_memory - p)
330 low_count = (unsigned long) high_memory - p;
331
332#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
333 /* we don't have page 0 mapped on sparc and m68k.. */
334 if (p < PAGE_SIZE && low_count > 0) {
335 size_t tmp = PAGE_SIZE - p;
336 if (tmp > low_count) tmp = low_count;
337 if (clear_user(buf, tmp))
338 return -EFAULT;
339 buf += tmp;
340 p += tmp;
341 read += tmp;
342 low_count -= tmp;
343 count -= tmp;
344 }
345#endif
346 while (low_count > 0) {
347 /*
348 * Handle first page in case it's not aligned
349 */
350 if (-p & (PAGE_SIZE - 1))
351 sz = -p & (PAGE_SIZE - 1);
352 else
353 sz = PAGE_SIZE;
354
355 sz = min_t(unsigned long, sz, low_count);
356
357 /*
358 * On ia64 if a page has been mapped somewhere as
359 * uncached, then it must also be accessed uncached
360 * by the kernel or data corruption may occur
361 */
362 kbuf = xlate_dev_kmem_ptr((char *)p);
363
364 if (copy_to_user(buf, kbuf, sz))
365 return -EFAULT;
366 buf += sz;
367 p += sz;
368 read += sz;
369 low_count -= sz;
370 count -= sz;
371 }
372 }
373
374 if (count > 0) {
375 kbuf = (char *)__get_free_page(GFP_KERNEL);
376 if (!kbuf)
377 return -ENOMEM;
378 while (count > 0) {
379 int len = count;
380
381 if (len > PAGE_SIZE)
382 len = PAGE_SIZE;
383 len = vread(kbuf, (char *)p, len);
384 if (!len)
385 break;
386 if (copy_to_user(buf, kbuf, len)) {
387 free_page((unsigned long)kbuf);
388 return -EFAULT;
389 }
390 count -= len;
391 buf += len;
392 read += len;
393 p += len;
394 }
395 free_page((unsigned long)kbuf);
396 }
397 *ppos = p;
398 return read;
399}
400
401
402static inline ssize_t
403do_write_kmem(void *p, unsigned long realp, const char __user * buf,
404 size_t count, loff_t *ppos)
405{
406 ssize_t written, sz;
407 unsigned long copied;
408
409 written = 0;
410#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
411 /* we don't have page 0 mapped on sparc and m68k.. */
412 if (realp < PAGE_SIZE) {
413 unsigned long sz = PAGE_SIZE - realp;
414 if (sz > count)
415 sz = count;
416 /* Hmm. Do something? */
417 buf += sz;
418 p += sz;
419 realp += sz;
420 count -= sz;
421 written += sz;
422 }
423#endif
424
425 while (count > 0) {
426 char *ptr;
427 /*
428 * Handle first page in case it's not aligned
429 */
430 if (-realp & (PAGE_SIZE - 1))
431 sz = -realp & (PAGE_SIZE - 1);
432 else
433 sz = PAGE_SIZE;
434
435 sz = min_t(unsigned long, sz, count);
436
437 /*
438 * On ia64 if a page has been mapped somewhere as
439 * uncached, then it must also be accessed uncached
440 * by the kernel or data corruption may occur
441 */
442 ptr = xlate_dev_kmem_ptr(p);
443
444 copied = copy_from_user(ptr, buf, sz);
445 if (copied) {
446 ssize_t ret;
447
448 ret = written + (sz - copied);
449 if (ret)
450 return ret;
451 return -EFAULT;
452 }
453 buf += sz;
454 p += sz;
455 realp += sz;
456 count -= sz;
457 written += sz;
458 }
459
460 *ppos += written;
461 return written;
462}
463
464
465/*
466 * This function writes to the *virtual* memory as seen by the kernel.
467 */
468static ssize_t write_kmem(struct file * file, const char __user * buf,
469 size_t count, loff_t *ppos)
470{
471 unsigned long p = *ppos;
472 ssize_t wrote = 0;
473 ssize_t virtr = 0;
474 ssize_t written;
475 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
476
477 if (p < (unsigned long) high_memory) {
478
479 wrote = count;
480 if (count > (unsigned long) high_memory - p)
481 wrote = (unsigned long) high_memory - p;
482
483 written = do_write_kmem((void*)p, p, buf, wrote, ppos);
484 if (written != wrote)
485 return written;
486 wrote = written;
487 p += wrote;
488 buf += wrote;
489 count -= wrote;
490 }
491
492 if (count > 0) {
493 kbuf = (char *)__get_free_page(GFP_KERNEL);
494 if (!kbuf)
495 return wrote ? wrote : -ENOMEM;
496 while (count > 0) {
497 int len = count;
498
499 if (len > PAGE_SIZE)
500 len = PAGE_SIZE;
501 if (len) {
502 written = copy_from_user(kbuf, buf, len);
503 if (written) {
504 ssize_t ret;
505
506 free_page((unsigned long)kbuf);
507 ret = wrote + virtr + (len - written);
508 return ret ? ret : -EFAULT;
509 }
510 }
511 len = vwrite(kbuf, (char *)p, len);
512 count -= len;
513 buf += len;
514 virtr += len;
515 p += len;
516 }
517 free_page((unsigned long)kbuf);
518 }
519
520 *ppos = p;
521 return virtr + wrote;
522}
523
145d01e4 524#if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
1da177e4
LT		 525static ssize_t read_port(struct file * file, char __user * buf,
526 size_t count, loff_t *ppos)
527{
528 unsigned long i = *ppos;
529 char __user *tmp = buf;
530
531 if (!access_ok(VERIFY_WRITE, buf, count))
532 return -EFAULT;
533 while (count-- > 0 && i < 65536) {
534 if (__put_user(inb(i),tmp) < 0)
535 return -EFAULT;
536 i++;
537 tmp++;
538 }
539 *ppos = i;
540 return tmp-buf;
541}
542
543static ssize_t write_port(struct file * file, const char __user * buf,
544 size_t count, loff_t *ppos)
545{
546 unsigned long i = *ppos;
547 const char __user * tmp = buf;
548
549 if (!access_ok(VERIFY_READ,buf,count))
550 return -EFAULT;
551 while (count-- > 0 && i < 65536) {
552 char c;
553 if (__get_user(c, tmp))
554 return -EFAULT;
555 outb(c,i);
556 i++;
557 tmp++;
558 }
559 *ppos = i;
560 return tmp-buf;
561}
562#endif
563
564static ssize_t read_null(struct file * file, char __user * buf,
565 size_t count, loff_t *ppos)
566{
567 return 0;
568}
569
570static ssize_t write_null(struct file * file, const char __user * buf,
571 size_t count, loff_t *ppos)
572{
573 return count;
574}
575
576#ifdef CONFIG_MMU
577/*
578 * For fun, we are using the MMU for this.
579 */
580static inline size_t read_zero_pagealigned(char __user * buf, size_t size)
581{
582 struct mm_struct *mm;
583 struct vm_area_struct * vma;
584 unsigned long addr=(unsigned long)buf;
585
586 mm = current->mm;
587 /* Oops, this was forgotten before. -ben */
588 down_read(&mm->mmap_sem);
589
590 /* For private mappings, just map in zero pages. */
591 for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
592 unsigned long count;
593
594 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0)
595 goto out_up;
596 if (vma->vm_flags & (VM_SHARED | VM_HUGETLB))
597 break;
598 count = vma->vm_end - addr;
599 if (count > size)
600 count = size;
601
602 zap_page_range(vma, addr, count, NULL);
603 zeromap_page_range(vma, addr, count, PAGE_COPY);
604
605 size -= count;
606 buf += count;
607 addr += count;
608 if (size == 0)
609 goto out_up;
610 }
611
612 up_read(&mm->mmap_sem);
613
614 /* The shared case is hard. Let's do the conventional zeroing. */
615 do {
616 unsigned long unwritten = clear_user(buf, PAGE_SIZE);
617 if (unwritten)
618 return size + unwritten - PAGE_SIZE;
619 cond_resched();
620 buf += PAGE_SIZE;
621 size -= PAGE_SIZE;
622 } while (size);
623
624 return size;
625out_up:
626 up_read(&mm->mmap_sem);
627 return size;
628}
629
630static ssize_t read_zero(struct file * file, char __user * buf,
631 size_t count, loff_t *ppos)
632{
633 unsigned long left, unwritten, written = 0;
634
635 if (!count)
636 return 0;
637
638 if (!access_ok(VERIFY_WRITE, buf, count))
639 return -EFAULT;
640
641 left = count;
642
643 /* do we want to be clever? Arbitrary cut-off */
644 if (count >= PAGE_SIZE*4) {
645 unsigned long partial;
646
647 /* How much left of the page? */
648 partial = (PAGE_SIZE-1) & -(unsigned long) buf;
649 unwritten = clear_user(buf, partial);
650 written = partial - unwritten;
651 if (unwritten)
652 goto out;
653 left -= partial;
654 buf += partial;
655 unwritten = read_zero_pagealigned(buf, left & PAGE_MASK);
656 written += (left & PAGE_MASK) - unwritten;
657 if (unwritten)
658 goto out;
659 buf += left & PAGE_MASK;
660 left &= ~PAGE_MASK;
661 }
662 unwritten = clear_user(buf, left);
663 written += left - unwritten;
664out:
665 return written ? written : -EFAULT;
666}
667
668static int mmap_zero(struct file * file, struct vm_area_struct * vma)
669{
670 if (vma->vm_flags & VM_SHARED)
671 return shmem_zero_setup(vma);
672 if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot))
673 return -EAGAIN;
674 return 0;
675}
676#else /* CONFIG_MMU */
677static ssize_t read_zero(struct file * file, char * buf,
678 size_t count, loff_t *ppos)
679{
680 size_t todo = count;
681
682 while (todo) {
683 size_t chunk = todo;
684
685 if (chunk > 4096)
686 chunk = 4096; /* Just for latency reasons */
687 if (clear_user(buf, chunk))
688 return -EFAULT;
689 buf += chunk;
690 todo -= chunk;
691 cond_resched();
692 }
693 return count;
694}
695
696static int mmap_zero(struct file * file, struct vm_area_struct * vma)
697{
698 return -ENOSYS;
699}
700#endif /* CONFIG_MMU */
701
702static ssize_t write_full(struct file * file, const char __user * buf,
703 size_t count, loff_t *ppos)
704{
705 return -ENOSPC;
706}
707
708/*
709 * Special lseek() function for /dev/null and /dev/zero. Most notably, you
710 * can fopen() both devices with "a" now. This was previously impossible.
711 * -- SRB.
712 */
713
714static loff_t null_lseek(struct file * file, loff_t offset, int orig)
715{
716 return file->f_pos = 0;
717}
718
719/*
720 * The memory devices use the full 32/64 bits of the offset, and so we cannot
721 * check against negative addresses: they are ok. The return value is weird,
722 * though, in that case (0).
723 *
724 * also note that seeking relative to the "end of file" isn't supported:
725 * it has no meaning, so it returns -EINVAL.
726 */
727static loff_t memory_lseek(struct file * file, loff_t offset, int orig)
728{
729 loff_t ret;
730
731 down(&file->f_dentry->d_inode->i_sem);
732 switch (orig) {
733 case 0:
734 file->f_pos = offset;
735 ret = file->f_pos;
736 force_successful_syscall_return();
737 break;
738 case 1:
739 file->f_pos += offset;
740 ret = file->f_pos;
741 force_successful_syscall_return();
742 break;
743 default:
744 ret = -EINVAL;
745 }
746 up(&file->f_dentry->d_inode->i_sem);
747 return ret;
748}
749
750static int open_port(struct inode * inode, struct file * filp)
751{
752 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
753}
754
755#define zero_lseek null_lseek
756#define full_lseek null_lseek
757#define write_zero write_null
758#define read_full read_zero
759#define open_mem open_port
760#define open_kmem open_mem
50b1fdbd 761#define open_oldmem open_mem
1da177e4
LT		 762
763static struct file_operations mem_fops = {
764 .llseek = memory_lseek,
765 .read = read_mem,
766 .write = write_mem,
767 .mmap = mmap_mem,
768 .open = open_mem,
769};
770
771static struct file_operations kmem_fops = {
772 .llseek = memory_lseek,
773 .read = read_kmem,
774 .write = write_kmem,
775 .mmap = mmap_kmem,
776 .open = open_kmem,
777};
778
779static struct file_operations null_fops = {
780 .llseek = null_lseek,
781 .read = read_null,
782 .write = write_null,
783};
784
145d01e4 785#if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
1da177e4
LT		 786static struct file_operations port_fops = {
787 .llseek = memory_lseek,
788 .read = read_port,
789 .write = write_port,
790 .open = open_port,
791};
792#endif
793
794static struct file_operations zero_fops = {
795 .llseek = zero_lseek,
796 .read = read_zero,
797 .write = write_zero,
798 .mmap = mmap_zero,
799};
800
801static struct backing_dev_info zero_bdi = {
802 .capabilities = BDI_CAP_MAP_COPY,
803};
804
805static struct file_operations full_fops = {
806 .llseek = full_lseek,
807 .read = read_full,
808 .write = write_full,
809};
810
50b1fdbd
VG		 811#ifdef CONFIG_CRASH_DUMP
812static struct file_operations oldmem_fops = {
813 .read = read_oldmem,
814 .open = open_oldmem,
815};
816#endif
817
1da177e4
LT		 818static ssize_t kmsg_write(struct file * file, const char __user * buf,
819 size_t count, loff_t *ppos)
820{
821 char *tmp;
822 int ret;
823
824 tmp = kmalloc(count + 1, GFP_KERNEL);
825 if (tmp == NULL)
826 return -ENOMEM;
827 ret = -EFAULT;
828 if (!copy_from_user(tmp, buf, count)) {
829 tmp[count] = 0;
830 ret = printk("%s", tmp);
831 }
832 kfree(tmp);
833 return ret;
834}
835
836static struct file_operations kmsg_fops = {
837 .write = kmsg_write,
838};
839
840static int memory_open(struct inode * inode, struct file * filp)
841{
842 switch (iminor(inode)) {
843 case 1:
844 filp->f_op = &mem_fops;
845 break;
846 case 2:
847 filp->f_op = &kmem_fops;
848 break;
849 case 3:
850 filp->f_op = &null_fops;
851 break;
145d01e4 852#if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
1da177e4
LT		 853 case 4:
854 filp->f_op = &port_fops;
855 break;
856#endif
857 case 5:
858 filp->f_mapping->backing_dev_info = &zero_bdi;
859 filp->f_op = &zero_fops;
860 break;
861 case 7:
862 filp->f_op = &full_fops;
863 break;
864 case 8:
865 filp->f_op = &random_fops;
866 break;
867 case 9:
868 filp->f_op = &urandom_fops;
869 break;
870 case 11:
871 filp->f_op = &kmsg_fops;
872 break;
50b1fdbd
VG		 873#ifdef CONFIG_CRASH_DUMP
874 case 12:
875 filp->f_op = &oldmem_fops;
876 break;
877#endif
1da177e4
LT		 878 default:
879 return -ENXIO;
880 }
881 if (filp->f_op && filp->f_op->open)
882 return filp->f_op->open(inode,filp);
883 return 0;
884}
885
886static struct file_operations memory_fops = {
887 .open = memory_open, /* just a selector for the real open */
888};
889
890static const struct {
891 unsigned int minor;
892 char *name;
893 umode_t mode;
894 struct file_operations *fops;
895} devlist[] = { /* list of minor devices */
896 {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
897 {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops},
898 {3, "null", S_IRUGO | S_IWUGO, &null_fops},
145d01e4 899#if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
1da177e4
LT		 900 {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops},
901#endif
902 {5, "zero", S_IRUGO | S_IWUGO, &zero_fops},
903 {7, "full", S_IRUGO | S_IWUGO, &full_fops},
904 {8, "random", S_IRUGO | S_IWUSR, &random_fops},
905 {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops},
906 {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops},
50b1fdbd
VG		 907#ifdef CONFIG_CRASH_DUMP
908 {12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops},
909#endif
1da177e4
LT		 910};
911
ca8eca68 912static struct class *mem_class;
1da177e4
LT		 913
914static int __init chr_dev_init(void)
915{
916 int i;
917
918 if (register_chrdev(MEM_MAJOR,"mem",&memory_fops))
919 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
920
ca8eca68 921 mem_class = class_create(THIS_MODULE, "mem");
1da177e4 922 for (i = 0; i < ARRAY_SIZE(devlist); i++) {
ca8eca68 923 class_device_create(mem_class, MKDEV(MEM_MAJOR, devlist[i].minor),
1da177e4
LT		 924 NULL, devlist[i].name);
925 devfs_mk_cdev(MKDEV(MEM_MAJOR, devlist[i].minor),
926 S_IFCHR | devlist[i].mode, devlist[i].name);
927 }
928
929 return 0;
930}
931
932fs_initcall(chr_dev_init);
kernel source for telekom puls (alcatel/mediatek)