Fix up mmap of /dev/kmem
[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 pfn;
265
266         /* Turn a kernel-virtual address into a physical page frame */
267         pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
268
269         /*
270          * RED-PEN: on some architectures there is more mapped memory
271          * than available in mem_map which pfn_valid checks
272          * for. Perhaps should add a new macro here.
273          *
274          * RED-PEN: vmalloc is not supported right now.
275          */
276         if (!pfn_valid(pfn))
277                 return -EIO;
278
279         vma->vm_pgoff = pfn;
280         return mmap_mem(file, vma);
281 }
282
283 #ifdef CONFIG_CRASH_DUMP
284 /*
285  * Read memory corresponding to the old kernel.
286  */
287 static ssize_t read_oldmem(struct file *file, char __user *buf,
288                                 size_t count, loff_t *ppos)
289 {
290         unsigned long pfn, offset;
291         size_t read = 0, csize;
292         int rc = 0;
293
294         while (count) {
295                 pfn = *ppos / PAGE_SIZE;
296                 if (pfn > saved_max_pfn)
297                         return read;
298
299                 offset = (unsigned long)(*ppos % PAGE_SIZE);
300                 if (count > PAGE_SIZE - offset)
301                         csize = PAGE_SIZE - offset;
302                 else
303                         csize = count;
304
305                 rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
306                 if (rc < 0)
307                         return rc;
308                 buf += csize;
309                 *ppos += csize;
310                 read += csize;
311                 count -= csize;
312         }
313         return read;
314 }
315 #endif
316
317 extern long vread(char *buf, char *addr, unsigned long count);
318 extern long vwrite(char *buf, char *addr, unsigned long count);
319
320 /*
321  * This function reads the *virtual* memory as seen by the kernel.
322  */
323 static ssize_t read_kmem(struct file *file, char __user *buf, 
324                          size_t count, loff_t *ppos)
325 {
326         unsigned long p = *ppos;
327         ssize_t low_count, read, sz;
328         char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
329
330         read = 0;
331         if (p < (unsigned long) high_memory) {
332                 low_count = count;
333                 if (count > (unsigned long) high_memory - p)
334                         low_count = (unsigned long) high_memory - p;
335
336 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
337                 /* we don't have page 0 mapped on sparc and m68k.. */
338                 if (p < PAGE_SIZE && low_count > 0) {
339                         size_t tmp = PAGE_SIZE - p;
340                         if (tmp > low_count) tmp = low_count;
341                         if (clear_user(buf, tmp))
342                                 return -EFAULT;
343                         buf += tmp;
344                         p += tmp;
345                         read += tmp;
346                         low_count -= tmp;
347                         count -= tmp;
348                 }
349 #endif
350                 while (low_count > 0) {
351                         /*
352                          * Handle first page in case it's not aligned
353                          */
354                         if (-p & (PAGE_SIZE - 1))
355                                 sz = -p & (PAGE_SIZE - 1);
356                         else
357                                 sz = PAGE_SIZE;
358
359                         sz = min_t(unsigned long, sz, low_count);
360
361                         /*
362                          * On ia64 if a page has been mapped somewhere as
363                          * uncached, then it must also be accessed uncached
364                          * by the kernel or data corruption may occur
365                          */
366                         kbuf = xlate_dev_kmem_ptr((char *)p);
367
368                         if (copy_to_user(buf, kbuf, sz))
369                                 return -EFAULT;
370                         buf += sz;
371                         p += sz;
372                         read += sz;
373                         low_count -= sz;
374                         count -= sz;
375                 }
376         }
377
378         if (count > 0) {
379                 kbuf = (char *)__get_free_page(GFP_KERNEL);
380                 if (!kbuf)
381                         return -ENOMEM;
382                 while (count > 0) {
383                         int len = count;
384
385                         if (len > PAGE_SIZE)
386                                 len = PAGE_SIZE;
387                         len = vread(kbuf, (char *)p, len);
388                         if (!len)
389                                 break;
390                         if (copy_to_user(buf, kbuf, len)) {
391                                 free_page((unsigned long)kbuf);
392                                 return -EFAULT;
393                         }
394                         count -= len;
395                         buf += len;
396                         read += len;
397                         p += len;
398                 }
399                 free_page((unsigned long)kbuf);
400         }
401         *ppos = p;
402         return read;
403 }
404
405
406 static inline ssize_t
407 do_write_kmem(void *p, unsigned long realp, const char __user * buf,
408               size_t count, loff_t *ppos)
409 {
410         ssize_t written, sz;
411         unsigned long copied;
412
413         written = 0;
414 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
415         /* we don't have page 0 mapped on sparc and m68k.. */
416         if (realp < PAGE_SIZE) {
417                 unsigned long sz = PAGE_SIZE - realp;
418                 if (sz > count)
419                         sz = count;
420                 /* Hmm. Do something? */
421                 buf += sz;
422                 p += sz;
423                 realp += sz;
424                 count -= sz;
425                 written += sz;
426         }
427 #endif
428
429         while (count > 0) {
430                 char *ptr;
431                 /*
432                  * Handle first page in case it's not aligned
433                  */
434                 if (-realp & (PAGE_SIZE - 1))
435                         sz = -realp & (PAGE_SIZE - 1);
436                 else
437                         sz = PAGE_SIZE;
438
439                 sz = min_t(unsigned long, sz, count);
440
441                 /*
442                  * On ia64 if a page has been mapped somewhere as
443                  * uncached, then it must also be accessed uncached
444                  * by the kernel or data corruption may occur
445                  */
446                 ptr = xlate_dev_kmem_ptr(p);
447
448                 copied = copy_from_user(ptr, buf, sz);
449                 if (copied) {
450                         ssize_t ret;
451
452                         ret = written + (sz - copied);
453                         if (ret)
454                                 return ret;
455                         return -EFAULT;
456                 }
457                 buf += sz;
458                 p += sz;
459                 realp += sz;
460                 count -= sz;
461                 written += sz;
462         }
463
464         *ppos += written;
465         return written;
466 }
467
468
469 /*
470  * This function writes to the *virtual* memory as seen by the kernel.
471  */
472 static ssize_t write_kmem(struct file * file, const char __user * buf, 
473                           size_t count, loff_t *ppos)
474 {
475         unsigned long p = *ppos;
476         ssize_t wrote = 0;
477         ssize_t virtr = 0;
478         ssize_t written;
479         char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
480
481         if (p < (unsigned long) high_memory) {
482
483                 wrote = count;
484                 if (count > (unsigned long) high_memory - p)
485                         wrote = (unsigned long) high_memory - p;
486
487                 written = do_write_kmem((void*)p, p, buf, wrote, ppos);
488                 if (written != wrote)
489                         return written;
490                 wrote = written;
491                 p += wrote;
492                 buf += wrote;
493                 count -= wrote;
494         }
495
496         if (count > 0) {
497                 kbuf = (char *)__get_free_page(GFP_KERNEL);
498                 if (!kbuf)
499                         return wrote ? wrote : -ENOMEM;
500                 while (count > 0) {
501                         int len = count;
502
503                         if (len > PAGE_SIZE)
504                                 len = PAGE_SIZE;
505                         if (len) {
506                                 written = copy_from_user(kbuf, buf, len);
507                                 if (written) {
508                                         ssize_t ret;
509
510                                         free_page((unsigned long)kbuf);
511                                         ret = wrote + virtr + (len - written);
512                                         return ret ? ret : -EFAULT;
513                                 }
514                         }
515                         len = vwrite(kbuf, (char *)p, len);
516                         count -= len;
517                         buf += len;
518                         virtr += len;
519                         p += len;
520                 }
521                 free_page((unsigned long)kbuf);
522         }
523
524         *ppos = p;
525         return virtr + wrote;
526 }
527
528 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
529 static ssize_t read_port(struct file * file, char __user * buf,
530                          size_t count, loff_t *ppos)
531 {
532         unsigned long i = *ppos;
533         char __user *tmp = buf;
534
535         if (!access_ok(VERIFY_WRITE, buf, count))
536                 return -EFAULT; 
537         while (count-- > 0 && i < 65536) {
538                 if (__put_user(inb(i),tmp) < 0) 
539                         return -EFAULT;  
540                 i++;
541                 tmp++;
542         }
543         *ppos = i;
544         return tmp-buf;
545 }
546
547 static ssize_t write_port(struct file * file, const char __user * buf,
548                           size_t count, loff_t *ppos)
549 {
550         unsigned long i = *ppos;
551         const char __user * tmp = buf;
552
553         if (!access_ok(VERIFY_READ,buf,count))
554                 return -EFAULT;
555         while (count-- > 0 && i < 65536) {
556                 char c;
557                 if (__get_user(c, tmp)) 
558                         return -EFAULT; 
559                 outb(c,i);
560                 i++;
561                 tmp++;
562         }
563         *ppos = i;
564         return tmp-buf;
565 }
566 #endif
567
568 static ssize_t read_null(struct file * file, char __user * buf,
569                          size_t count, loff_t *ppos)
570 {
571         return 0;
572 }
573
574 static ssize_t write_null(struct file * file, const char __user * buf,
575                           size_t count, loff_t *ppos)
576 {
577         return count;
578 }
579
580 #ifdef CONFIG_MMU
581 /*
582  * For fun, we are using the MMU for this.
583  */
584 static inline size_t read_zero_pagealigned(char __user * buf, size_t size)
585 {
586         struct mm_struct *mm;
587         struct vm_area_struct * vma;
588         unsigned long addr=(unsigned long)buf;
589
590         mm = current->mm;
591         /* Oops, this was forgotten before. -ben */
592         down_read(&mm->mmap_sem);
593
594         /* For private mappings, just map in zero pages. */
595         for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
596                 unsigned long count;
597
598                 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0)
599                         goto out_up;
600                 if (vma->vm_flags & (VM_SHARED | VM_HUGETLB))
601                         break;
602                 count = vma->vm_end - addr;
603                 if (count > size)
604                         count = size;
605
606                 zap_page_range(vma, addr, count, NULL);
607                 zeromap_page_range(vma, addr, count, PAGE_COPY);
608
609                 size -= count;
610                 buf += count;
611                 addr += count;
612                 if (size == 0)
613                         goto out_up;
614         }
615
616         up_read(&mm->mmap_sem);
617         
618         /* The shared case is hard. Let's do the conventional zeroing. */ 
619         do {
620                 unsigned long unwritten = clear_user(buf, PAGE_SIZE);
621                 if (unwritten)
622                         return size + unwritten - PAGE_SIZE;
623                 cond_resched();
624                 buf += PAGE_SIZE;
625                 size -= PAGE_SIZE;
626         } while (size);
627
628         return size;
629 out_up:
630         up_read(&mm->mmap_sem);
631         return size;
632 }
633
634 static ssize_t read_zero(struct file * file, char __user * buf, 
635                          size_t count, loff_t *ppos)
636 {
637         unsigned long left, unwritten, written = 0;
638
639         if (!count)
640                 return 0;
641
642         if (!access_ok(VERIFY_WRITE, buf, count))
643                 return -EFAULT;
644
645         left = count;
646
647         /* do we want to be clever? Arbitrary cut-off */
648         if (count >= PAGE_SIZE*4) {
649                 unsigned long partial;
650
651                 /* How much left of the page? */
652                 partial = (PAGE_SIZE-1) & -(unsigned long) buf;
653                 unwritten = clear_user(buf, partial);
654                 written = partial - unwritten;
655                 if (unwritten)
656                         goto out;
657                 left -= partial;
658                 buf += partial;
659                 unwritten = read_zero_pagealigned(buf, left & PAGE_MASK);
660                 written += (left & PAGE_MASK) - unwritten;
661                 if (unwritten)
662                         goto out;
663                 buf += left & PAGE_MASK;
664                 left &= ~PAGE_MASK;
665         }
666         unwritten = clear_user(buf, left);
667         written += left - unwritten;
668 out:
669         return written ? written : -EFAULT;
670 }
671
672 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
673 {
674         if (vma->vm_flags & VM_SHARED)
675                 return shmem_zero_setup(vma);
676         if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot))
677                 return -EAGAIN;
678         return 0;
679 }
680 #else /* CONFIG_MMU */
681 static ssize_t read_zero(struct file * file, char * buf, 
682                          size_t count, loff_t *ppos)
683 {
684         size_t todo = count;
685
686         while (todo) {
687                 size_t chunk = todo;
688
689                 if (chunk > 4096)
690                         chunk = 4096;   /* Just for latency reasons */
691                 if (clear_user(buf, chunk))
692                         return -EFAULT;
693                 buf += chunk;
694                 todo -= chunk;
695                 cond_resched();
696         }
697         return count;
698 }
699
700 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
701 {
702         return -ENOSYS;
703 }
704 #endif /* CONFIG_MMU */
705
706 static ssize_t write_full(struct file * file, const char __user * buf,
707                           size_t count, loff_t *ppos)
708 {
709         return -ENOSPC;
710 }
711
712 /*
713  * Special lseek() function for /dev/null and /dev/zero.  Most notably, you
714  * can fopen() both devices with "a" now.  This was previously impossible.
715  * -- SRB.
716  */
717
718 static loff_t null_lseek(struct file * file, loff_t offset, int orig)
719 {
720         return file->f_pos = 0;
721 }
722
723 /*
724  * The memory devices use the full 32/64 bits of the offset, and so we cannot
725  * check against negative addresses: they are ok. The return value is weird,
726  * though, in that case (0).
727  *
728  * also note that seeking relative to the "end of file" isn't supported:
729  * it has no meaning, so it returns -EINVAL.
730  */
731 static loff_t memory_lseek(struct file * file, loff_t offset, int orig)
732 {
733         loff_t ret;
734
735         down(&file->f_dentry->d_inode->i_sem);
736         switch (orig) {
737                 case 0:
738                         file->f_pos = offset;
739                         ret = file->f_pos;
740                         force_successful_syscall_return();
741                         break;
742                 case 1:
743                         file->f_pos += offset;
744                         ret = file->f_pos;
745                         force_successful_syscall_return();
746                         break;
747                 default:
748                         ret = -EINVAL;
749         }
750         up(&file->f_dentry->d_inode->i_sem);
751         return ret;
752 }
753
754 static int open_port(struct inode * inode, struct file * filp)
755 {
756         return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
757 }
758
759 #define zero_lseek      null_lseek
760 #define full_lseek      null_lseek
761 #define write_zero      write_null
762 #define read_full       read_zero
763 #define open_mem        open_port
764 #define open_kmem       open_mem
765 #define open_oldmem     open_mem
766
767 static struct file_operations mem_fops = {
768         .llseek         = memory_lseek,
769         .read           = read_mem,
770         .write          = write_mem,
771         .mmap           = mmap_mem,
772         .open           = open_mem,
773 };
774
775 static struct file_operations kmem_fops = {
776         .llseek         = memory_lseek,
777         .read           = read_kmem,
778         .write          = write_kmem,
779         .mmap           = mmap_kmem,
780         .open           = open_kmem,
781 };
782
783 static struct file_operations null_fops = {
784         .llseek         = null_lseek,
785         .read           = read_null,
786         .write          = write_null,
787 };
788
789 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
790 static struct file_operations port_fops = {
791         .llseek         = memory_lseek,
792         .read           = read_port,
793         .write          = write_port,
794         .open           = open_port,
795 };
796 #endif
797
798 static struct file_operations zero_fops = {
799         .llseek         = zero_lseek,
800         .read           = read_zero,
801         .write          = write_zero,
802         .mmap           = mmap_zero,
803 };
804
805 static struct backing_dev_info zero_bdi = {
806         .capabilities   = BDI_CAP_MAP_COPY,
807 };
808
809 static struct file_operations full_fops = {
810         .llseek         = full_lseek,
811         .read           = read_full,
812         .write          = write_full,
813 };
814
815 #ifdef CONFIG_CRASH_DUMP
816 static struct file_operations oldmem_fops = {
817         .read   = read_oldmem,
818         .open   = open_oldmem,
819 };
820 #endif
821
822 static ssize_t kmsg_write(struct file * file, const char __user * buf,
823                           size_t count, loff_t *ppos)
824 {
825         char *tmp;
826         int ret;
827
828         tmp = kmalloc(count + 1, GFP_KERNEL);
829         if (tmp == NULL)
830                 return -ENOMEM;
831         ret = -EFAULT;
832         if (!copy_from_user(tmp, buf, count)) {
833                 tmp[count] = 0;
834                 ret = printk("%s", tmp);
835         }
836         kfree(tmp);
837         return ret;
838 }
839
840 static struct file_operations kmsg_fops = {
841         .write =        kmsg_write,
842 };
843
844 static int memory_open(struct inode * inode, struct file * filp)
845 {
846         switch (iminor(inode)) {
847                 case 1:
848                         filp->f_op = &mem_fops;
849                         break;
850                 case 2:
851                         filp->f_op = &kmem_fops;
852                         break;
853                 case 3:
854                         filp->f_op = &null_fops;
855                         break;
856 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
857                 case 4:
858                         filp->f_op = &port_fops;
859                         break;
860 #endif
861                 case 5:
862                         filp->f_mapping->backing_dev_info = &zero_bdi;
863                         filp->f_op = &zero_fops;
864                         break;
865                 case 7:
866                         filp->f_op = &full_fops;
867                         break;
868                 case 8:
869                         filp->f_op = &random_fops;
870                         break;
871                 case 9:
872                         filp->f_op = &urandom_fops;
873                         break;
874                 case 11:
875                         filp->f_op = &kmsg_fops;
876                         break;
877 #ifdef CONFIG_CRASH_DUMP
878                 case 12:
879                         filp->f_op = &oldmem_fops;
880                         break;
881 #endif
882                 default:
883                         return -ENXIO;
884         }
885         if (filp->f_op && filp->f_op->open)
886                 return filp->f_op->open(inode,filp);
887         return 0;
888 }
889
890 static struct file_operations memory_fops = {
891         .open           = memory_open,  /* just a selector for the real open */
892 };
893
894 static const struct {
895         unsigned int            minor;
896         char                    *name;
897         umode_t                 mode;
898         struct file_operations  *fops;
899 } devlist[] = { /* list of minor devices */
900         {1, "mem",     S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
901         {2, "kmem",    S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops},
902         {3, "null",    S_IRUGO | S_IWUGO,           &null_fops},
903 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI))
904         {4, "port",    S_IRUSR | S_IWUSR | S_IRGRP, &port_fops},
905 #endif
906         {5, "zero",    S_IRUGO | S_IWUGO,           &zero_fops},
907         {7, "full",    S_IRUGO | S_IWUGO,           &full_fops},
908         {8, "random",  S_IRUGO | S_IWUSR,           &random_fops},
909         {9, "urandom", S_IRUGO | S_IWUSR,           &urandom_fops},
910         {11,"kmsg",    S_IRUGO | S_IWUSR,           &kmsg_fops},
911 #ifdef CONFIG_CRASH_DUMP
912         {12,"oldmem",    S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops},
913 #endif
914 };
915
916 static struct class *mem_class;
917
918 static int __init chr_dev_init(void)
919 {
920         int i;
921
922         if (register_chrdev(MEM_MAJOR,"mem",&memory_fops))
923                 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
924
925         mem_class = class_create(THIS_MODULE, "mem");
926         for (i = 0; i < ARRAY_SIZE(devlist); i++) {
927                 class_device_create(mem_class, MKDEV(MEM_MAJOR, devlist[i].minor),
928                                         NULL, devlist[i].name);
929                 devfs_mk_cdev(MKDEV(MEM_MAJOR, devlist[i].minor),
930                                 S_IFCHR | devlist[i].mode, devlist[i].name);
931         }
932         
933         return 0;
934 }
935
936 fs_initcall(chr_dev_init);