[PATCH] EFI, /dev/mem: simplify efi_mem_attribute_range()
[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 /*
39  * Architectures vary in how they handle caching for addresses
40  * outside of main memory.
41  *
42  */
43 static inline int uncached_access(struct file *file, unsigned long addr)
44 {
45 #if defined(__i386__)
46         /*
47          * On the PPro and successors, the MTRRs are used to set
48          * memory types for physical addresses outside main memory,
49          * so blindly setting PCD or PWT on those pages is wrong.
50          * For Pentiums and earlier, the surround logic should disable
51          * caching for the high addresses through the KEN pin, but
52          * we maintain the tradition of paranoia in this code.
53          */
54         if (file->f_flags & O_SYNC)
55                 return 1;
56         return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) ||
57                   test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) ||
58                   test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) ||
59                   test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) )
60           && addr >= __pa(high_memory);
61 #elif defined(__x86_64__)
62         /* 
63          * This is broken because it can generate memory type aliases,
64          * which can cause cache corruptions
65          * But it is only available for root and we have to be bug-to-bug
66          * compatible with i386.
67          */
68         if (file->f_flags & O_SYNC)
69                 return 1;
70         /* same behaviour as i386. PAT always set to cached and MTRRs control the
71            caching behaviour. 
72            Hopefully a full PAT implementation will fix that soon. */      
73         return 0;
74 #elif defined(CONFIG_IA64)
75         /*
76          * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
77          */
78         return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
79 #else
80         /*
81          * Accessing memory above the top the kernel knows about or through a file pointer
82          * that was marked O_SYNC will be done non-cached.
83          */
84         if (file->f_flags & O_SYNC)
85                 return 1;
86         return addr >= __pa(high_memory);
87 #endif
88 }
89
90 #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
91 static inline int valid_phys_addr_range(unsigned long addr, size_t count)
92 {
93         if (addr + count > __pa(high_memory))
94                 return 0;
95
96         return 1;
97 }
98
99 static inline int valid_mmap_phys_addr_range(unsigned long addr, size_t size)
100 {
101         return 1;
102 }
103 #endif
104
105 /*
106  * This funcion reads the *physical* memory. The f_pos points directly to the 
107  * memory location. 
108  */
109 static ssize_t read_mem(struct file * file, char __user * buf,
110                         size_t count, loff_t *ppos)
111 {
112         unsigned long p = *ppos;
113         ssize_t read, sz;
114         char *ptr;
115
116         if (!valid_phys_addr_range(p, count))
117                 return -EFAULT;
118         read = 0;
119 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
120         /* we don't have page 0 mapped on sparc and m68k.. */
121         if (p < PAGE_SIZE) {
122                 sz = PAGE_SIZE - p;
123                 if (sz > count) 
124                         sz = count; 
125                 if (sz > 0) {
126                         if (clear_user(buf, sz))
127                                 return -EFAULT;
128                         buf += sz; 
129                         p += sz; 
130                         count -= sz; 
131                         read += sz; 
132                 }
133         }
134 #endif
135
136         while (count > 0) {
137                 /*
138                  * Handle first page in case it's not aligned
139                  */
140                 if (-p & (PAGE_SIZE - 1))
141                         sz = -p & (PAGE_SIZE - 1);
142                 else
143                         sz = PAGE_SIZE;
144
145                 sz = min_t(unsigned long, sz, count);
146
147                 /*
148                  * On ia64 if a page has been mapped somewhere as
149                  * uncached, then it must also be accessed uncached
150                  * by the kernel or data corruption may occur
151                  */
152                 ptr = xlate_dev_mem_ptr(p);
153
154                 if (copy_to_user(buf, ptr, sz))
155                         return -EFAULT;
156                 buf += sz;
157                 p += sz;
158                 count -= sz;
159                 read += sz;
160         }
161
162         *ppos += read;
163         return read;
164 }
165
166 static ssize_t write_mem(struct file * file, const char __user * buf, 
167                          size_t count, loff_t *ppos)
168 {
169         unsigned long p = *ppos;
170         ssize_t written, sz;
171         unsigned long copied;
172         void *ptr;
173
174         if (!valid_phys_addr_range(p, count))
175                 return -EFAULT;
176
177         written = 0;
178
179 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
180         /* we don't have page 0 mapped on sparc and m68k.. */
181         if (p < PAGE_SIZE) {
182                 unsigned long sz = PAGE_SIZE - p;
183                 if (sz > count)
184                         sz = count;
185                 /* Hmm. Do something? */
186                 buf += sz;
187                 p += sz;
188                 count -= sz;
189                 written += sz;
190         }
191 #endif
192
193         while (count > 0) {
194                 /*
195                  * Handle first page in case it's not aligned
196                  */
197                 if (-p & (PAGE_SIZE - 1))
198                         sz = -p & (PAGE_SIZE - 1);
199                 else
200                         sz = PAGE_SIZE;
201
202                 sz = min_t(unsigned long, sz, count);
203
204                 /*
205                  * On ia64 if a page has been mapped somewhere as
206                  * uncached, then it must also be accessed uncached
207                  * by the kernel or data corruption may occur
208                  */
209                 ptr = xlate_dev_mem_ptr(p);
210
211                 copied = copy_from_user(ptr, buf, sz);
212                 if (copied) {
213                         written += sz - copied;
214                         if (written)
215                                 break;
216                         return -EFAULT;
217                 }
218                 buf += sz;
219                 p += sz;
220                 count -= sz;
221                 written += sz;
222         }
223
224         *ppos += written;
225         return written;
226 }
227
228 #ifndef __HAVE_PHYS_MEM_ACCESS_PROT
229 static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
230                                      unsigned long size, pgprot_t vma_prot)
231 {
232 #ifdef pgprot_noncached
233         unsigned long offset = pfn << PAGE_SHIFT;
234
235         if (uncached_access(file, offset))
236                 return pgprot_noncached(vma_prot);
237 #endif
238         return vma_prot;
239 }
240 #endif
241
242 static int mmap_mem(struct file * file, struct vm_area_struct * vma)
243 {
244         size_t size = vma->vm_end - vma->vm_start;
245
246         if (!valid_mmap_phys_addr_range(vma->vm_pgoff << PAGE_SHIFT, size))
247                 return -EINVAL;
248
249         vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
250                                                  size,
251                                                  vma->vm_page_prot);
252
253         /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
254         if (remap_pfn_range(vma,
255                             vma->vm_start,
256                             vma->vm_pgoff,
257                             size,
258                             vma->vm_page_prot))
259                 return -EAGAIN;
260         return 0;
261 }
262
263 static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
264 {
265         unsigned long pfn;
266
267         /* Turn a kernel-virtual address into a physical page frame */
268         pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
269
270         /*
271          * RED-PEN: on some architectures there is more mapped memory
272          * than available in mem_map which pfn_valid checks
273          * for. Perhaps should add a new macro here.
274          *
275          * RED-PEN: vmalloc is not supported right now.
276          */
277         if (!pfn_valid(pfn))
278                 return -EIO;
279
280         vma->vm_pgoff = pfn;
281         return mmap_mem(file, vma);
282 }
283
284 #ifdef CONFIG_CRASH_DUMP
285 /*
286  * Read memory corresponding to the old kernel.
287  */
288 static ssize_t read_oldmem(struct file *file, char __user *buf,
289                                 size_t count, loff_t *ppos)
290 {
291         unsigned long pfn, offset;
292         size_t read = 0, csize;
293         int rc = 0;
294
295         while (count) {
296                 pfn = *ppos / PAGE_SIZE;
297                 if (pfn > saved_max_pfn)
298                         return read;
299
300                 offset = (unsigned long)(*ppos % PAGE_SIZE);
301                 if (count > PAGE_SIZE - offset)
302                         csize = PAGE_SIZE - offset;
303                 else
304                         csize = count;
305
306                 rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
307                 if (rc < 0)
308                         return rc;
309                 buf += csize;
310                 *ppos += csize;
311                 read += csize;
312                 count -= csize;
313         }
314         return read;
315 }
316 #endif
317
318 extern long vread(char *buf, char *addr, unsigned long count);
319 extern long vwrite(char *buf, char *addr, unsigned long count);
320
321 /*
322  * This function reads the *virtual* memory as seen by the kernel.
323  */
324 static ssize_t read_kmem(struct file *file, char __user *buf, 
325                          size_t count, loff_t *ppos)
326 {
327         unsigned long p = *ppos;
328         ssize_t low_count, read, sz;
329         char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
330
331         read = 0;
332         if (p < (unsigned long) high_memory) {
333                 low_count = count;
334                 if (count > (unsigned long) high_memory - p)
335                         low_count = (unsigned long) high_memory - p;
336
337 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
338                 /* we don't have page 0 mapped on sparc and m68k.. */
339                 if (p < PAGE_SIZE && low_count > 0) {
340                         size_t tmp = PAGE_SIZE - p;
341                         if (tmp > low_count) tmp = low_count;
342                         if (clear_user(buf, tmp))
343                                 return -EFAULT;
344                         buf += tmp;
345                         p += tmp;
346                         read += tmp;
347                         low_count -= tmp;
348                         count -= tmp;
349                 }
350 #endif
351                 while (low_count > 0) {
352                         /*
353                          * Handle first page in case it's not aligned
354                          */
355                         if (-p & (PAGE_SIZE - 1))
356                                 sz = -p & (PAGE_SIZE - 1);
357                         else
358                                 sz = PAGE_SIZE;
359
360                         sz = min_t(unsigned long, sz, low_count);
361
362                         /*
363                          * On ia64 if a page has been mapped somewhere as
364                          * uncached, then it must also be accessed uncached
365                          * by the kernel or data corruption may occur
366                          */
367                         kbuf = xlate_dev_kmem_ptr((char *)p);
368
369                         if (copy_to_user(buf, kbuf, sz))
370                                 return -EFAULT;
371                         buf += sz;
372                         p += sz;
373                         read += sz;
374                         low_count -= sz;
375                         count -= sz;
376                 }
377         }
378
379         if (count > 0) {
380                 kbuf = (char *)__get_free_page(GFP_KERNEL);
381                 if (!kbuf)
382                         return -ENOMEM;
383                 while (count > 0) {
384                         int len = count;
385
386                         if (len > PAGE_SIZE)
387                                 len = PAGE_SIZE;
388                         len = vread(kbuf, (char *)p, len);
389                         if (!len)
390                                 break;
391                         if (copy_to_user(buf, kbuf, len)) {
392                                 free_page((unsigned long)kbuf);
393                                 return -EFAULT;
394                         }
395                         count -= len;
396                         buf += len;
397                         read += len;
398                         p += len;
399                 }
400                 free_page((unsigned long)kbuf);
401         }
402         *ppos = p;
403         return read;
404 }
405
406
407 static inline ssize_t
408 do_write_kmem(void *p, unsigned long realp, const char __user * buf,
409               size_t count, loff_t *ppos)
410 {
411         ssize_t written, sz;
412         unsigned long copied;
413
414         written = 0;
415 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
416         /* we don't have page 0 mapped on sparc and m68k.. */
417         if (realp < PAGE_SIZE) {
418                 unsigned long sz = PAGE_SIZE - realp;
419                 if (sz > count)
420                         sz = count;
421                 /* Hmm. Do something? */
422                 buf += sz;
423                 p += sz;
424                 realp += sz;
425                 count -= sz;
426                 written += sz;
427         }
428 #endif
429
430         while (count > 0) {
431                 char *ptr;
432                 /*
433                  * Handle first page in case it's not aligned
434                  */
435                 if (-realp & (PAGE_SIZE - 1))
436                         sz = -realp & (PAGE_SIZE - 1);
437                 else
438                         sz = PAGE_SIZE;
439
440                 sz = min_t(unsigned long, sz, count);
441
442                 /*
443                  * On ia64 if a page has been mapped somewhere as
444                  * uncached, then it must also be accessed uncached
445                  * by the kernel or data corruption may occur
446                  */
447                 ptr = xlate_dev_kmem_ptr(p);
448
449                 copied = copy_from_user(ptr, buf, sz);
450                 if (copied) {
451                         written += sz - copied;
452                         if (written)
453                                 break;
454                         return -EFAULT;
455                 }
456                 buf += sz;
457                 p += sz;
458                 realp += sz;
459                 count -= sz;
460                 written += sz;
461         }
462
463         *ppos += written;
464         return written;
465 }
466
467
468 /*
469  * This function writes to the *virtual* memory as seen by the kernel.
470  */
471 static ssize_t write_kmem(struct file * file, const char __user * buf, 
472                           size_t count, loff_t *ppos)
473 {
474         unsigned long p = *ppos;
475         ssize_t wrote = 0;
476         ssize_t virtr = 0;
477         ssize_t written;
478         char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
479
480         if (p < (unsigned long) high_memory) {
481
482                 wrote = count;
483                 if (count > (unsigned long) high_memory - p)
484                         wrote = (unsigned long) high_memory - p;
485
486                 written = do_write_kmem((void*)p, p, buf, wrote, ppos);
487                 if (written != wrote)
488                         return written;
489                 wrote = written;
490                 p += wrote;
491                 buf += wrote;
492                 count -= wrote;
493         }
494
495         if (count > 0) {
496                 kbuf = (char *)__get_free_page(GFP_KERNEL);
497                 if (!kbuf)
498                         return wrote ? wrote : -ENOMEM;
499                 while (count > 0) {
500                         int len = count;
501
502                         if (len > PAGE_SIZE)
503                                 len = PAGE_SIZE;
504                         if (len) {
505                                 written = copy_from_user(kbuf, buf, len);
506                                 if (written) {
507                                         if (wrote + virtr)
508                                                 break;
509                                         free_page((unsigned long)kbuf);
510                                         return -EFAULT;
511                                 }
512                         }
513                         len = vwrite(kbuf, (char *)p, len);
514                         count -= len;
515                         buf += len;
516                         virtr += len;
517                         p += len;
518                 }
519                 free_page((unsigned long)kbuf);
520         }
521
522         *ppos = p;
523         return virtr + wrote;
524 }
525
526 #if defined(CONFIG_ISA) || !defined(__mc68000__)
527 static ssize_t read_port(struct file * file, char __user * buf,
528                          size_t count, loff_t *ppos)
529 {
530         unsigned long i = *ppos;
531         char __user *tmp = buf;
532
533         if (!access_ok(VERIFY_WRITE, buf, count))
534                 return -EFAULT; 
535         while (count-- > 0 && i < 65536) {
536                 if (__put_user(inb(i),tmp) < 0) 
537                         return -EFAULT;  
538                 i++;
539                 tmp++;
540         }
541         *ppos = i;
542         return tmp-buf;
543 }
544
545 static ssize_t write_port(struct file * file, const char __user * buf,
546                           size_t count, loff_t *ppos)
547 {
548         unsigned long i = *ppos;
549         const char __user * tmp = buf;
550
551         if (!access_ok(VERIFY_READ,buf,count))
552                 return -EFAULT;
553         while (count-- > 0 && i < 65536) {
554                 char c;
555                 if (__get_user(c, tmp)) {
556                         if (tmp > buf)
557                                 break;
558                         return -EFAULT; 
559                 }
560                 outb(c,i);
561                 i++;
562                 tmp++;
563         }
564         *ppos = i;
565         return tmp-buf;
566 }
567 #endif
568
569 static ssize_t read_null(struct file * file, char __user * buf,
570                          size_t count, loff_t *ppos)
571 {
572         return 0;
573 }
574
575 static ssize_t write_null(struct file * file, const char __user * buf,
576                           size_t count, loff_t *ppos)
577 {
578         return count;
579 }
580
581 #ifdef CONFIG_MMU
582 /*
583  * For fun, we are using the MMU for this.
584  */
585 static inline size_t read_zero_pagealigned(char __user * buf, size_t size)
586 {
587         struct mm_struct *mm;
588         struct vm_area_struct * vma;
589         unsigned long addr=(unsigned long)buf;
590
591         mm = current->mm;
592         /* Oops, this was forgotten before. -ben */
593         down_read(&mm->mmap_sem);
594
595         /* For private mappings, just map in zero pages. */
596         for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
597                 unsigned long count;
598
599                 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0)
600                         goto out_up;
601                 if (vma->vm_flags & (VM_SHARED | VM_HUGETLB))
602                         break;
603                 count = vma->vm_end - addr;
604                 if (count > size)
605                         count = size;
606
607                 zap_page_range(vma, addr, count, NULL);
608                 zeromap_page_range(vma, addr, count, PAGE_COPY);
609
610                 size -= count;
611                 buf += count;
612                 addr += count;
613                 if (size == 0)
614                         goto out_up;
615         }
616
617         up_read(&mm->mmap_sem);
618         
619         /* The shared case is hard. Let's do the conventional zeroing. */ 
620         do {
621                 unsigned long unwritten = clear_user(buf, PAGE_SIZE);
622                 if (unwritten)
623                         return size + unwritten - PAGE_SIZE;
624                 cond_resched();
625                 buf += PAGE_SIZE;
626                 size -= PAGE_SIZE;
627         } while (size);
628
629         return size;
630 out_up:
631         up_read(&mm->mmap_sem);
632         return size;
633 }
634
635 static ssize_t read_zero(struct file * file, char __user * buf, 
636                          size_t count, loff_t *ppos)
637 {
638         unsigned long left, unwritten, written = 0;
639
640         if (!count)
641                 return 0;
642
643         if (!access_ok(VERIFY_WRITE, buf, count))
644                 return -EFAULT;
645
646         left = count;
647
648         /* do we want to be clever? Arbitrary cut-off */
649         if (count >= PAGE_SIZE*4) {
650                 unsigned long partial;
651
652                 /* How much left of the page? */
653                 partial = (PAGE_SIZE-1) & -(unsigned long) buf;
654                 unwritten = clear_user(buf, partial);
655                 written = partial - unwritten;
656                 if (unwritten)
657                         goto out;
658                 left -= partial;
659                 buf += partial;
660                 unwritten = read_zero_pagealigned(buf, left & PAGE_MASK);
661                 written += (left & PAGE_MASK) - unwritten;
662                 if (unwritten)
663                         goto out;
664                 buf += left & PAGE_MASK;
665                 left &= ~PAGE_MASK;
666         }
667         unwritten = clear_user(buf, left);
668         written += left - unwritten;
669 out:
670         return written ? written : -EFAULT;
671 }
672
673 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
674 {
675         if (vma->vm_flags & VM_SHARED)
676                 return shmem_zero_setup(vma);
677         if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot))
678                 return -EAGAIN;
679         return 0;
680 }
681 #else /* CONFIG_MMU */
682 static ssize_t read_zero(struct file * file, char * buf, 
683                          size_t count, loff_t *ppos)
684 {
685         size_t todo = count;
686
687         while (todo) {
688                 size_t chunk = todo;
689
690                 if (chunk > 4096)
691                         chunk = 4096;   /* Just for latency reasons */
692                 if (clear_user(buf, chunk))
693                         return -EFAULT;
694                 buf += chunk;
695                 todo -= chunk;
696                 cond_resched();
697         }
698         return count;
699 }
700
701 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
702 {
703         return -ENOSYS;
704 }
705 #endif /* CONFIG_MMU */
706
707 static ssize_t write_full(struct file * file, const char __user * buf,
708                           size_t count, loff_t *ppos)
709 {
710         return -ENOSPC;
711 }
712
713 /*
714  * Special lseek() function for /dev/null and /dev/zero.  Most notably, you
715  * can fopen() both devices with "a" now.  This was previously impossible.
716  * -- SRB.
717  */
718
719 static loff_t null_lseek(struct file * file, loff_t offset, int orig)
720 {
721         return file->f_pos = 0;
722 }
723
724 /*
725  * The memory devices use the full 32/64 bits of the offset, and so we cannot
726  * check against negative addresses: they are ok. The return value is weird,
727  * though, in that case (0).
728  *
729  * also note that seeking relative to the "end of file" isn't supported:
730  * it has no meaning, so it returns -EINVAL.
731  */
732 static loff_t memory_lseek(struct file * file, loff_t offset, int orig)
733 {
734         loff_t ret;
735
736         mutex_lock(&file->f_dentry->d_inode->i_mutex);
737         switch (orig) {
738                 case 0:
739                         file->f_pos = offset;
740                         ret = file->f_pos;
741                         force_successful_syscall_return();
742                         break;
743                 case 1:
744                         file->f_pos += offset;
745                         ret = file->f_pos;
746                         force_successful_syscall_return();
747                         break;
748                 default:
749                         ret = -EINVAL;
750         }
751         mutex_unlock(&file->f_dentry->d_inode->i_mutex);
752         return ret;
753 }
754
755 static int open_port(struct inode * inode, struct file * filp)
756 {
757         return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
758 }
759
760 #define zero_lseek      null_lseek
761 #define full_lseek      null_lseek
762 #define write_zero      write_null
763 #define read_full       read_zero
764 #define open_mem        open_port
765 #define open_kmem       open_mem
766 #define open_oldmem     open_mem
767
768 static struct file_operations mem_fops = {
769         .llseek         = memory_lseek,
770         .read           = read_mem,
771         .write          = write_mem,
772         .mmap           = mmap_mem,
773         .open           = open_mem,
774 };
775
776 static struct file_operations kmem_fops = {
777         .llseek         = memory_lseek,
778         .read           = read_kmem,
779         .write          = write_kmem,
780         .mmap           = mmap_kmem,
781         .open           = open_kmem,
782 };
783
784 static struct file_operations null_fops = {
785         .llseek         = null_lseek,
786         .read           = read_null,
787         .write          = write_null,
788 };
789
790 #if defined(CONFIG_ISA) || !defined(__mc68000__)
791 static struct file_operations port_fops = {
792         .llseek         = memory_lseek,
793         .read           = read_port,
794         .write          = write_port,
795         .open           = open_port,
796 };
797 #endif
798
799 static struct file_operations zero_fops = {
800         .llseek         = zero_lseek,
801         .read           = read_zero,
802         .write          = write_zero,
803         .mmap           = mmap_zero,
804 };
805
806 static struct backing_dev_info zero_bdi = {
807         .capabilities   = BDI_CAP_MAP_COPY,
808 };
809
810 static struct file_operations full_fops = {
811         .llseek         = full_lseek,
812         .read           = read_full,
813         .write          = write_full,
814 };
815
816 #ifdef CONFIG_CRASH_DUMP
817 static struct file_operations oldmem_fops = {
818         .read   = read_oldmem,
819         .open   = open_oldmem,
820 };
821 #endif
822
823 static ssize_t kmsg_write(struct file * file, const char __user * buf,
824                           size_t count, loff_t *ppos)
825 {
826         char *tmp;
827         ssize_t ret;
828
829         tmp = kmalloc(count + 1, GFP_KERNEL);
830         if (tmp == NULL)
831                 return -ENOMEM;
832         ret = -EFAULT;
833         if (!copy_from_user(tmp, buf, count)) {
834                 tmp[count] = 0;
835                 ret = printk("%s", tmp);
836                 if (ret > count)
837                         /* printk can add a prefix */
838                         ret = count;
839         }
840         kfree(tmp);
841         return ret;
842 }
843
844 static struct file_operations kmsg_fops = {
845         .write =        kmsg_write,
846 };
847
848 static int memory_open(struct inode * inode, struct file * filp)
849 {
850         switch (iminor(inode)) {
851                 case 1:
852                         filp->f_op = &mem_fops;
853                         break;
854                 case 2:
855                         filp->f_op = &kmem_fops;
856                         break;
857                 case 3:
858                         filp->f_op = &null_fops;
859                         break;
860 #if defined(CONFIG_ISA) || !defined(__mc68000__)
861                 case 4:
862                         filp->f_op = &port_fops;
863                         break;
864 #endif
865                 case 5:
866                         filp->f_mapping->backing_dev_info = &zero_bdi;
867                         filp->f_op = &zero_fops;
868                         break;
869                 case 7:
870                         filp->f_op = &full_fops;
871                         break;
872                 case 8:
873                         filp->f_op = &random_fops;
874                         break;
875                 case 9:
876                         filp->f_op = &urandom_fops;
877                         break;
878                 case 11:
879                         filp->f_op = &kmsg_fops;
880                         break;
881 #ifdef CONFIG_CRASH_DUMP
882                 case 12:
883                         filp->f_op = &oldmem_fops;
884                         break;
885 #endif
886                 default:
887                         return -ENXIO;
888         }
889         if (filp->f_op && filp->f_op->open)
890                 return filp->f_op->open(inode,filp);
891         return 0;
892 }
893
894 static struct file_operations memory_fops = {
895         .open           = memory_open,  /* just a selector for the real open */
896 };
897
898 static const struct {
899         unsigned int            minor;
900         char                    *name;
901         umode_t                 mode;
902         struct file_operations  *fops;
903 } devlist[] = { /* list of minor devices */
904         {1, "mem",     S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
905         {2, "kmem",    S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops},
906         {3, "null",    S_IRUGO | S_IWUGO,           &null_fops},
907 #if defined(CONFIG_ISA) || !defined(__mc68000__)
908         {4, "port",    S_IRUSR | S_IWUSR | S_IRGRP, &port_fops},
909 #endif
910         {5, "zero",    S_IRUGO | S_IWUGO,           &zero_fops},
911         {7, "full",    S_IRUGO | S_IWUGO,           &full_fops},
912         {8, "random",  S_IRUGO | S_IWUSR,           &random_fops},
913         {9, "urandom", S_IRUGO | S_IWUSR,           &urandom_fops},
914         {11,"kmsg",    S_IRUGO | S_IWUSR,           &kmsg_fops},
915 #ifdef CONFIG_CRASH_DUMP
916         {12,"oldmem",    S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops},
917 #endif
918 };
919
920 static struct class *mem_class;
921
922 static int __init chr_dev_init(void)
923 {
924         int i;
925
926         if (register_chrdev(MEM_MAJOR,"mem",&memory_fops))
927                 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
928
929         mem_class = class_create(THIS_MODULE, "mem");
930         for (i = 0; i < ARRAY_SIZE(devlist); i++) {
931                 class_device_create(mem_class, NULL,
932                                         MKDEV(MEM_MAJOR, devlist[i].minor),
933                                         NULL, devlist[i].name);
934                 devfs_mk_cdev(MKDEV(MEM_MAJOR, devlist[i].minor),
935                                 S_IFCHR | devlist[i].mode, devlist[i].name);
936         }
937         
938         return 0;
939 }
940
941 fs_initcall(chr_dev_init);