[PATCH] kdump: cleanups for dump file access in linear raw format
[linux-2.6.git] / drivers / char / mem.c
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/highmem.h>
27 #include <linux/crash_dump.h>
28 #include <linux/backing-dev.h>
29 #include <linux/bootmem.h>
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)
39 extern 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  */
47 static 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
95 static 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  */
114 static 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
171 static 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
235 static 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
262 static 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
279 #ifdef CONFIG_CRASH_DUMP
280 /*
281  * Read memory corresponding to the old kernel.
282  */
283 static ssize_t read_oldmem(struct file *file, char __user *buf,
284                                 size_t count, loff_t *ppos)
285 {
286         unsigned long pfn, offset;
287         size_t read = 0, csize;
288         int rc = 0;
289
290         while(count) {
291                 pfn = *ppos / PAGE_SIZE;
292                 if (pfn > saved_max_pfn)
293                         return read;
294
295                 offset = (unsigned long)(*ppos % PAGE_SIZE);
296                 if (count > PAGE_SIZE - offset)
297                         csize = PAGE_SIZE - offset;
298                 else
299                         csize = count;
300
301                 rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
302                 if (rc < 0)
303                         return rc;
304                 buf += csize;
305                 *ppos += csize;
306                 read += csize;
307                 count -= csize;
308         }
309         return read;
310 }
311 #endif
312
313 extern long vread(char *buf, char *addr, unsigned long count);
314 extern long vwrite(char *buf, char *addr, unsigned long count);
315
316 /*
317  * This function reads the *virtual* memory as seen by the kernel.
318  */
319 static 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
402 static inline ssize_t
403 do_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  */
468 static 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
524 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
525 static 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
543 static 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
564 static ssize_t read_null(struct file * file, char __user * buf,
565                          size_t count, loff_t *ppos)
566 {
567         return 0;
568 }
569
570 static 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  */
580 static 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;
625 out_up:
626         up_read(&mm->mmap_sem);
627         return size;
628 }
629
630 static 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;
664 out:
665         return written ? written : -EFAULT;
666 }
667
668 static 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 */
677 static 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
696 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
697 {
698         return -ENOSYS;
699 }
700 #endif /* CONFIG_MMU */
701
702 static 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
714 static 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  */
727 static 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
750 static 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
761 #define open_oldmem     open_mem
762
763 static 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
771 static 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
779 static struct file_operations null_fops = {
780         .llseek         = null_lseek,
781         .read           = read_null,
782         .write          = write_null,
783 };
784
785 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
786 static 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
794 static struct file_operations zero_fops = {
795         .llseek         = zero_lseek,
796         .read           = read_zero,
797         .write          = write_zero,
798         .mmap           = mmap_zero,
799 };
800
801 static struct backing_dev_info zero_bdi = {
802         .capabilities   = BDI_CAP_MAP_COPY,
803 };
804
805 static struct file_operations full_fops = {
806         .llseek         = full_lseek,
807         .read           = read_full,
808         .write          = write_full,
809 };
810
811 #ifdef CONFIG_CRASH_DUMP
812 static struct file_operations oldmem_fops = {
813         .read   = read_oldmem,
814         .open   = open_oldmem,
815 };
816 #endif
817
818 static 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
836 static struct file_operations kmsg_fops = {
837         .write =        kmsg_write,
838 };
839
840 static 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;
852 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
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;
873 #ifdef CONFIG_CRASH_DUMP
874                 case 12:
875                         filp->f_op = &oldmem_fops;
876                         break;
877 #endif
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
886 static struct file_operations memory_fops = {
887         .open           = memory_open,  /* just a selector for the real open */
888 };
889
890 static 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},
899 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
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},
907 #ifdef CONFIG_CRASH_DUMP
908         {12,"oldmem",    S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops},
909 #endif
910 };
911
912 static struct class *mem_class;
913
914 static 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
921         mem_class = class_create(THIS_MODULE, "mem");
922         for (i = 0; i < ARRAY_SIZE(devlist); i++) {
923                 class_device_create(mem_class, MKDEV(MEM_MAJOR, devlist[i].minor),
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
932 fs_initcall(chr_dev_init);