device create: char: convert device_create_drvdata to device_create
[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/mm.h>
12 #include <linux/miscdevice.h>
13 #include <linux/slab.h>
14 #include <linux/vmalloc.h>
15 #include <linux/mman.h>
16 #include <linux/random.h>
17 #include <linux/init.h>
18 #include <linux/raw.h>
19 #include <linux/tty.h>
20 #include <linux/capability.h>
21 #include <linux/ptrace.h>
22 #include <linux/device.h>
23 #include <linux/highmem.h>
24 #include <linux/crash_dump.h>
25 #include <linux/backing-dev.h>
26 #include <linux/bootmem.h>
27 #include <linux/splice.h>
28 #include <linux/pfn.h>
29 #include <linux/smp_lock.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(CONFIG_IA64)
46         /*
47          * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
48          */
49         return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
50 #elif defined(CONFIG_MIPS)
51         {
52                 extern int __uncached_access(struct file *file,
53                                              unsigned long addr);
54
55                 return __uncached_access(file, addr);
56         }
57 #else
58         /*
59          * Accessing memory above the top the kernel knows about or through a file pointer
60          * that was marked O_SYNC will be done non-cached.
61          */
62         if (file->f_flags & O_SYNC)
63                 return 1;
64         return addr >= __pa(high_memory);
65 #endif
66 }
67
68 #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
69 static inline int valid_phys_addr_range(unsigned long addr, size_t count)
70 {
71         if (addr + count > __pa(high_memory))
72                 return 0;
73
74         return 1;
75 }
76
77 static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
78 {
79         return 1;
80 }
81 #endif
82
83 #ifdef CONFIG_STRICT_DEVMEM
84 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
85 {
86         u64 from = ((u64)pfn) << PAGE_SHIFT;
87         u64 to = from + size;
88         u64 cursor = from;
89
90         while (cursor < to) {
91                 if (!devmem_is_allowed(pfn)) {
92                         printk(KERN_INFO
93                 "Program %s tried to access /dev/mem between %Lx->%Lx.\n",
94                                 current->comm, from, to);
95                         return 0;
96                 }
97                 cursor += PAGE_SIZE;
98                 pfn++;
99         }
100         return 1;
101 }
102 #else
103 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
104 {
105         return 1;
106 }
107 #endif
108
109 void __attribute__((weak)) unxlate_dev_mem_ptr(unsigned long phys, void *addr)
110 {
111 }
112
113 /*
114  * This funcion reads the *physical* memory. The f_pos points directly to the 
115  * memory location. 
116  */
117 static ssize_t read_mem(struct file * file, char __user * buf,
118                         size_t count, loff_t *ppos)
119 {
120         unsigned long p = *ppos;
121         ssize_t read, sz;
122         char *ptr;
123
124         if (!valid_phys_addr_range(p, count))
125                 return -EFAULT;
126         read = 0;
127 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
128         /* we don't have page 0 mapped on sparc and m68k.. */
129         if (p < PAGE_SIZE) {
130                 sz = PAGE_SIZE - p;
131                 if (sz > count) 
132                         sz = count; 
133                 if (sz > 0) {
134                         if (clear_user(buf, sz))
135                                 return -EFAULT;
136                         buf += sz; 
137                         p += sz; 
138                         count -= sz; 
139                         read += sz; 
140                 }
141         }
142 #endif
143
144         while (count > 0) {
145                 /*
146                  * Handle first page in case it's not aligned
147                  */
148                 if (-p & (PAGE_SIZE - 1))
149                         sz = -p & (PAGE_SIZE - 1);
150                 else
151                         sz = PAGE_SIZE;
152
153                 sz = min_t(unsigned long, sz, count);
154
155                 if (!range_is_allowed(p >> PAGE_SHIFT, count))
156                         return -EPERM;
157
158                 /*
159                  * On ia64 if a page has been mapped somewhere as
160                  * uncached, then it must also be accessed uncached
161                  * by the kernel or data corruption may occur
162                  */
163                 ptr = xlate_dev_mem_ptr(p);
164                 if (!ptr)
165                         return -EFAULT;
166
167                 if (copy_to_user(buf, ptr, sz)) {
168                         unxlate_dev_mem_ptr(p, ptr);
169                         return -EFAULT;
170                 }
171
172                 unxlate_dev_mem_ptr(p, ptr);
173
174                 buf += sz;
175                 p += sz;
176                 count -= sz;
177                 read += sz;
178         }
179
180         *ppos += read;
181         return read;
182 }
183
184 static ssize_t write_mem(struct file * file, const char __user * buf, 
185                          size_t count, loff_t *ppos)
186 {
187         unsigned long p = *ppos;
188         ssize_t written, sz;
189         unsigned long copied;
190         void *ptr;
191
192         if (!valid_phys_addr_range(p, count))
193                 return -EFAULT;
194
195         written = 0;
196
197 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
198         /* we don't have page 0 mapped on sparc and m68k.. */
199         if (p < PAGE_SIZE) {
200                 unsigned long sz = PAGE_SIZE - p;
201                 if (sz > count)
202                         sz = count;
203                 /* Hmm. Do something? */
204                 buf += sz;
205                 p += sz;
206                 count -= sz;
207                 written += sz;
208         }
209 #endif
210
211         while (count > 0) {
212                 /*
213                  * Handle first page in case it's not aligned
214                  */
215                 if (-p & (PAGE_SIZE - 1))
216                         sz = -p & (PAGE_SIZE - 1);
217                 else
218                         sz = PAGE_SIZE;
219
220                 sz = min_t(unsigned long, sz, count);
221
222                 if (!range_is_allowed(p >> PAGE_SHIFT, sz))
223                         return -EPERM;
224
225                 /*
226                  * On ia64 if a page has been mapped somewhere as
227                  * uncached, then it must also be accessed uncached
228                  * by the kernel or data corruption may occur
229                  */
230                 ptr = xlate_dev_mem_ptr(p);
231                 if (!ptr) {
232                         if (written)
233                                 break;
234                         return -EFAULT;
235                 }
236
237                 copied = copy_from_user(ptr, buf, sz);
238                 if (copied) {
239                         written += sz - copied;
240                         unxlate_dev_mem_ptr(p, ptr);
241                         if (written)
242                                 break;
243                         return -EFAULT;
244                 }
245
246                 unxlate_dev_mem_ptr(p, ptr);
247
248                 buf += sz;
249                 p += sz;
250                 count -= sz;
251                 written += sz;
252         }
253
254         *ppos += written;
255         return written;
256 }
257
258 int __attribute__((weak)) phys_mem_access_prot_allowed(struct file *file,
259         unsigned long pfn, unsigned long size, pgprot_t *vma_prot)
260 {
261         return 1;
262 }
263
264 #ifndef __HAVE_PHYS_MEM_ACCESS_PROT
265 static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
266                                      unsigned long size, pgprot_t vma_prot)
267 {
268 #ifdef pgprot_noncached
269         unsigned long offset = pfn << PAGE_SHIFT;
270
271         if (uncached_access(file, offset))
272                 return pgprot_noncached(vma_prot);
273 #endif
274         return vma_prot;
275 }
276 #endif
277
278 #ifndef CONFIG_MMU
279 static unsigned long get_unmapped_area_mem(struct file *file,
280                                            unsigned long addr,
281                                            unsigned long len,
282                                            unsigned long pgoff,
283                                            unsigned long flags)
284 {
285         if (!valid_mmap_phys_addr_range(pgoff, len))
286                 return (unsigned long) -EINVAL;
287         return pgoff << PAGE_SHIFT;
288 }
289
290 /* can't do an in-place private mapping if there's no MMU */
291 static inline int private_mapping_ok(struct vm_area_struct *vma)
292 {
293         return vma->vm_flags & VM_MAYSHARE;
294 }
295 #else
296 #define get_unmapped_area_mem   NULL
297
298 static inline int private_mapping_ok(struct vm_area_struct *vma)
299 {
300         return 1;
301 }
302 #endif
303
304 void __attribute__((weak))
305 map_devmem(unsigned long pfn, unsigned long len, pgprot_t prot)
306 {
307         /* nothing. architectures can override. */
308 }
309
310 void __attribute__((weak))
311 unmap_devmem(unsigned long pfn, unsigned long len, pgprot_t prot)
312 {
313         /* nothing. architectures can override. */
314 }
315
316 static void mmap_mem_open(struct vm_area_struct *vma)
317 {
318         map_devmem(vma->vm_pgoff,  vma->vm_end - vma->vm_start,
319                         vma->vm_page_prot);
320 }
321
322 static void mmap_mem_close(struct vm_area_struct *vma)
323 {
324         unmap_devmem(vma->vm_pgoff,  vma->vm_end - vma->vm_start,
325                         vma->vm_page_prot);
326 }
327
328 static struct vm_operations_struct mmap_mem_ops = {
329         .open  = mmap_mem_open,
330         .close = mmap_mem_close,
331 #ifdef CONFIG_HAVE_IOREMAP_PROT
332         .access = generic_access_phys
333 #endif
334 };
335
336 static int mmap_mem(struct file * file, struct vm_area_struct * vma)
337 {
338         size_t size = vma->vm_end - vma->vm_start;
339
340         if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
341                 return -EINVAL;
342
343         if (!private_mapping_ok(vma))
344                 return -ENOSYS;
345
346         if (!range_is_allowed(vma->vm_pgoff, size))
347                 return -EPERM;
348
349         if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size,
350                                                 &vma->vm_page_prot))
351                 return -EINVAL;
352
353         vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
354                                                  size,
355                                                  vma->vm_page_prot);
356
357         vma->vm_ops = &mmap_mem_ops;
358
359         /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
360         if (remap_pfn_range(vma,
361                             vma->vm_start,
362                             vma->vm_pgoff,
363                             size,
364                             vma->vm_page_prot)) {
365                 unmap_devmem(vma->vm_pgoff, size, vma->vm_page_prot);
366                 return -EAGAIN;
367         }
368         return 0;
369 }
370
371 #ifdef CONFIG_DEVKMEM
372 static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
373 {
374         unsigned long pfn;
375
376         /* Turn a kernel-virtual address into a physical page frame */
377         pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
378
379         /*
380          * RED-PEN: on some architectures there is more mapped memory
381          * than available in mem_map which pfn_valid checks
382          * for. Perhaps should add a new macro here.
383          *
384          * RED-PEN: vmalloc is not supported right now.
385          */
386         if (!pfn_valid(pfn))
387                 return -EIO;
388
389         vma->vm_pgoff = pfn;
390         return mmap_mem(file, vma);
391 }
392 #endif
393
394 #ifdef CONFIG_CRASH_DUMP
395 /*
396  * Read memory corresponding to the old kernel.
397  */
398 static ssize_t read_oldmem(struct file *file, char __user *buf,
399                                 size_t count, loff_t *ppos)
400 {
401         unsigned long pfn, offset;
402         size_t read = 0, csize;
403         int rc = 0;
404
405         while (count) {
406                 pfn = *ppos / PAGE_SIZE;
407                 if (pfn > saved_max_pfn)
408                         return read;
409
410                 offset = (unsigned long)(*ppos % PAGE_SIZE);
411                 if (count > PAGE_SIZE - offset)
412                         csize = PAGE_SIZE - offset;
413                 else
414                         csize = count;
415
416                 rc = copy_oldmem_page(pfn, buf, csize, offset, 1);
417                 if (rc < 0)
418                         return rc;
419                 buf += csize;
420                 *ppos += csize;
421                 read += csize;
422                 count -= csize;
423         }
424         return read;
425 }
426 #endif
427
428 extern long vread(char *buf, char *addr, unsigned long count);
429 extern long vwrite(char *buf, char *addr, unsigned long count);
430
431 #ifdef CONFIG_DEVKMEM
432 /*
433  * This function reads the *virtual* memory as seen by the kernel.
434  */
435 static ssize_t read_kmem(struct file *file, char __user *buf, 
436                          size_t count, loff_t *ppos)
437 {
438         unsigned long p = *ppos;
439         ssize_t low_count, read, sz;
440         char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
441
442         read = 0;
443         if (p < (unsigned long) high_memory) {
444                 low_count = count;
445                 if (count > (unsigned long) high_memory - p)
446                         low_count = (unsigned long) high_memory - p;
447
448 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
449                 /* we don't have page 0 mapped on sparc and m68k.. */
450                 if (p < PAGE_SIZE && low_count > 0) {
451                         size_t tmp = PAGE_SIZE - p;
452                         if (tmp > low_count) tmp = low_count;
453                         if (clear_user(buf, tmp))
454                                 return -EFAULT;
455                         buf += tmp;
456                         p += tmp;
457                         read += tmp;
458                         low_count -= tmp;
459                         count -= tmp;
460                 }
461 #endif
462                 while (low_count > 0) {
463                         /*
464                          * Handle first page in case it's not aligned
465                          */
466                         if (-p & (PAGE_SIZE - 1))
467                                 sz = -p & (PAGE_SIZE - 1);
468                         else
469                                 sz = PAGE_SIZE;
470
471                         sz = min_t(unsigned long, sz, low_count);
472
473                         /*
474                          * On ia64 if a page has been mapped somewhere as
475                          * uncached, then it must also be accessed uncached
476                          * by the kernel or data corruption may occur
477                          */
478                         kbuf = xlate_dev_kmem_ptr((char *)p);
479
480                         if (copy_to_user(buf, kbuf, sz))
481                                 return -EFAULT;
482                         buf += sz;
483                         p += sz;
484                         read += sz;
485                         low_count -= sz;
486                         count -= sz;
487                 }
488         }
489
490         if (count > 0) {
491                 kbuf = (char *)__get_free_page(GFP_KERNEL);
492                 if (!kbuf)
493                         return -ENOMEM;
494                 while (count > 0) {
495                         int len = count;
496
497                         if (len > PAGE_SIZE)
498                                 len = PAGE_SIZE;
499                         len = vread(kbuf, (char *)p, len);
500                         if (!len)
501                                 break;
502                         if (copy_to_user(buf, kbuf, len)) {
503                                 free_page((unsigned long)kbuf);
504                                 return -EFAULT;
505                         }
506                         count -= len;
507                         buf += len;
508                         read += len;
509                         p += len;
510                 }
511                 free_page((unsigned long)kbuf);
512         }
513         *ppos = p;
514         return read;
515 }
516
517
518 static inline ssize_t
519 do_write_kmem(void *p, unsigned long realp, const char __user * buf,
520               size_t count, loff_t *ppos)
521 {
522         ssize_t written, sz;
523         unsigned long copied;
524
525         written = 0;
526 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
527         /* we don't have page 0 mapped on sparc and m68k.. */
528         if (realp < PAGE_SIZE) {
529                 unsigned long sz = PAGE_SIZE - realp;
530                 if (sz > count)
531                         sz = count;
532                 /* Hmm. Do something? */
533                 buf += sz;
534                 p += sz;
535                 realp += sz;
536                 count -= sz;
537                 written += sz;
538         }
539 #endif
540
541         while (count > 0) {
542                 char *ptr;
543                 /*
544                  * Handle first page in case it's not aligned
545                  */
546                 if (-realp & (PAGE_SIZE - 1))
547                         sz = -realp & (PAGE_SIZE - 1);
548                 else
549                         sz = PAGE_SIZE;
550
551                 sz = min_t(unsigned long, sz, count);
552
553                 /*
554                  * On ia64 if a page has been mapped somewhere as
555                  * uncached, then it must also be accessed uncached
556                  * by the kernel or data corruption may occur
557                  */
558                 ptr = xlate_dev_kmem_ptr(p);
559
560                 copied = copy_from_user(ptr, buf, sz);
561                 if (copied) {
562                         written += sz - copied;
563                         if (written)
564                                 break;
565                         return -EFAULT;
566                 }
567                 buf += sz;
568                 p += sz;
569                 realp += sz;
570                 count -= sz;
571                 written += sz;
572         }
573
574         *ppos += written;
575         return written;
576 }
577
578
579 /*
580  * This function writes to the *virtual* memory as seen by the kernel.
581  */
582 static ssize_t write_kmem(struct file * file, const char __user * buf, 
583                           size_t count, loff_t *ppos)
584 {
585         unsigned long p = *ppos;
586         ssize_t wrote = 0;
587         ssize_t virtr = 0;
588         ssize_t written;
589         char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
590
591         if (p < (unsigned long) high_memory) {
592
593                 wrote = count;
594                 if (count > (unsigned long) high_memory - p)
595                         wrote = (unsigned long) high_memory - p;
596
597                 written = do_write_kmem((void*)p, p, buf, wrote, ppos);
598                 if (written != wrote)
599                         return written;
600                 wrote = written;
601                 p += wrote;
602                 buf += wrote;
603                 count -= wrote;
604         }
605
606         if (count > 0) {
607                 kbuf = (char *)__get_free_page(GFP_KERNEL);
608                 if (!kbuf)
609                         return wrote ? wrote : -ENOMEM;
610                 while (count > 0) {
611                         int len = count;
612
613                         if (len > PAGE_SIZE)
614                                 len = PAGE_SIZE;
615                         if (len) {
616                                 written = copy_from_user(kbuf, buf, len);
617                                 if (written) {
618                                         if (wrote + virtr)
619                                                 break;
620                                         free_page((unsigned long)kbuf);
621                                         return -EFAULT;
622                                 }
623                         }
624                         len = vwrite(kbuf, (char *)p, len);
625                         count -= len;
626                         buf += len;
627                         virtr += len;
628                         p += len;
629                 }
630                 free_page((unsigned long)kbuf);
631         }
632
633         *ppos = p;
634         return virtr + wrote;
635 }
636 #endif
637
638 #ifdef CONFIG_DEVPORT
639 static ssize_t read_port(struct file * file, char __user * buf,
640                          size_t count, loff_t *ppos)
641 {
642         unsigned long i = *ppos;
643         char __user *tmp = buf;
644
645         if (!access_ok(VERIFY_WRITE, buf, count))
646                 return -EFAULT; 
647         while (count-- > 0 && i < 65536) {
648                 if (__put_user(inb(i),tmp) < 0) 
649                         return -EFAULT;  
650                 i++;
651                 tmp++;
652         }
653         *ppos = i;
654         return tmp-buf;
655 }
656
657 static ssize_t write_port(struct file * file, const char __user * buf,
658                           size_t count, loff_t *ppos)
659 {
660         unsigned long i = *ppos;
661         const char __user * tmp = buf;
662
663         if (!access_ok(VERIFY_READ,buf,count))
664                 return -EFAULT;
665         while (count-- > 0 && i < 65536) {
666                 char c;
667                 if (__get_user(c, tmp)) {
668                         if (tmp > buf)
669                                 break;
670                         return -EFAULT; 
671                 }
672                 outb(c,i);
673                 i++;
674                 tmp++;
675         }
676         *ppos = i;
677         return tmp-buf;
678 }
679 #endif
680
681 static ssize_t read_null(struct file * file, char __user * buf,
682                          size_t count, loff_t *ppos)
683 {
684         return 0;
685 }
686
687 static ssize_t write_null(struct file * file, const char __user * buf,
688                           size_t count, loff_t *ppos)
689 {
690         return count;
691 }
692
693 static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
694                         struct splice_desc *sd)
695 {
696         return sd->len;
697 }
698
699 static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out,
700                                  loff_t *ppos, size_t len, unsigned int flags)
701 {
702         return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
703 }
704
705 static ssize_t read_zero(struct file * file, char __user * buf, 
706                          size_t count, loff_t *ppos)
707 {
708         size_t written;
709
710         if (!count)
711                 return 0;
712
713         if (!access_ok(VERIFY_WRITE, buf, count))
714                 return -EFAULT;
715
716         written = 0;
717         while (count) {
718                 unsigned long unwritten;
719                 size_t chunk = count;
720
721                 if (chunk > PAGE_SIZE)
722                         chunk = PAGE_SIZE;      /* Just for latency reasons */
723                 unwritten = clear_user(buf, chunk);
724                 written += chunk - unwritten;
725                 if (unwritten)
726                         break;
727                 buf += chunk;
728                 count -= chunk;
729                 cond_resched();
730         }
731         return written ? written : -EFAULT;
732 }
733
734 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
735 {
736 #ifndef CONFIG_MMU
737         return -ENOSYS;
738 #endif
739         if (vma->vm_flags & VM_SHARED)
740                 return shmem_zero_setup(vma);
741         return 0;
742 }
743
744 static ssize_t write_full(struct file * file, const char __user * buf,
745                           size_t count, loff_t *ppos)
746 {
747         return -ENOSPC;
748 }
749
750 /*
751  * Special lseek() function for /dev/null and /dev/zero.  Most notably, you
752  * can fopen() both devices with "a" now.  This was previously impossible.
753  * -- SRB.
754  */
755
756 static loff_t null_lseek(struct file * file, loff_t offset, int orig)
757 {
758         return file->f_pos = 0;
759 }
760
761 /*
762  * The memory devices use the full 32/64 bits of the offset, and so we cannot
763  * check against negative addresses: they are ok. The return value is weird,
764  * though, in that case (0).
765  *
766  * also note that seeking relative to the "end of file" isn't supported:
767  * it has no meaning, so it returns -EINVAL.
768  */
769 static loff_t memory_lseek(struct file * file, loff_t offset, int orig)
770 {
771         loff_t ret;
772
773         mutex_lock(&file->f_path.dentry->d_inode->i_mutex);
774         switch (orig) {
775                 case 0:
776                         file->f_pos = offset;
777                         ret = file->f_pos;
778                         force_successful_syscall_return();
779                         break;
780                 case 1:
781                         file->f_pos += offset;
782                         ret = file->f_pos;
783                         force_successful_syscall_return();
784                         break;
785                 default:
786                         ret = -EINVAL;
787         }
788         mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
789         return ret;
790 }
791
792 static int open_port(struct inode * inode, struct file * filp)
793 {
794         return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
795 }
796
797 #define zero_lseek      null_lseek
798 #define full_lseek      null_lseek
799 #define write_zero      write_null
800 #define read_full       read_zero
801 #define open_mem        open_port
802 #define open_kmem       open_mem
803 #define open_oldmem     open_mem
804
805 static const struct file_operations mem_fops = {
806         .llseek         = memory_lseek,
807         .read           = read_mem,
808         .write          = write_mem,
809         .mmap           = mmap_mem,
810         .open           = open_mem,
811         .get_unmapped_area = get_unmapped_area_mem,
812 };
813
814 #ifdef CONFIG_DEVKMEM
815 static const struct file_operations kmem_fops = {
816         .llseek         = memory_lseek,
817         .read           = read_kmem,
818         .write          = write_kmem,
819         .mmap           = mmap_kmem,
820         .open           = open_kmem,
821         .get_unmapped_area = get_unmapped_area_mem,
822 };
823 #endif
824
825 static const struct file_operations null_fops = {
826         .llseek         = null_lseek,
827         .read           = read_null,
828         .write          = write_null,
829         .splice_write   = splice_write_null,
830 };
831
832 #ifdef CONFIG_DEVPORT
833 static const struct file_operations port_fops = {
834         .llseek         = memory_lseek,
835         .read           = read_port,
836         .write          = write_port,
837         .open           = open_port,
838 };
839 #endif
840
841 static const struct file_operations zero_fops = {
842         .llseek         = zero_lseek,
843         .read           = read_zero,
844         .write          = write_zero,
845         .mmap           = mmap_zero,
846 };
847
848 /*
849  * capabilities for /dev/zero
850  * - permits private mappings, "copies" are taken of the source of zeros
851  */
852 static struct backing_dev_info zero_bdi = {
853         .capabilities   = BDI_CAP_MAP_COPY,
854 };
855
856 static const struct file_operations full_fops = {
857         .llseek         = full_lseek,
858         .read           = read_full,
859         .write          = write_full,
860 };
861
862 #ifdef CONFIG_CRASH_DUMP
863 static const struct file_operations oldmem_fops = {
864         .read   = read_oldmem,
865         .open   = open_oldmem,
866 };
867 #endif
868
869 static ssize_t kmsg_write(struct file * file, const char __user * buf,
870                           size_t count, loff_t *ppos)
871 {
872         char *tmp;
873         ssize_t ret;
874
875         tmp = kmalloc(count + 1, GFP_KERNEL);
876         if (tmp == NULL)
877                 return -ENOMEM;
878         ret = -EFAULT;
879         if (!copy_from_user(tmp, buf, count)) {
880                 tmp[count] = 0;
881                 ret = printk("%s", tmp);
882                 if (ret > count)
883                         /* printk can add a prefix */
884                         ret = count;
885         }
886         kfree(tmp);
887         return ret;
888 }
889
890 static const struct file_operations kmsg_fops = {
891         .write =        kmsg_write,
892 };
893
894 static int memory_open(struct inode * inode, struct file * filp)
895 {
896         int ret = 0;
897
898         lock_kernel();
899         switch (iminor(inode)) {
900                 case 1:
901                         filp->f_op = &mem_fops;
902                         filp->f_mapping->backing_dev_info =
903                                 &directly_mappable_cdev_bdi;
904                         break;
905 #ifdef CONFIG_DEVKMEM
906                 case 2:
907                         filp->f_op = &kmem_fops;
908                         filp->f_mapping->backing_dev_info =
909                                 &directly_mappable_cdev_bdi;
910                         break;
911 #endif
912                 case 3:
913                         filp->f_op = &null_fops;
914                         break;
915 #ifdef CONFIG_DEVPORT
916                 case 4:
917                         filp->f_op = &port_fops;
918                         break;
919 #endif
920                 case 5:
921                         filp->f_mapping->backing_dev_info = &zero_bdi;
922                         filp->f_op = &zero_fops;
923                         break;
924                 case 7:
925                         filp->f_op = &full_fops;
926                         break;
927                 case 8:
928                         filp->f_op = &random_fops;
929                         break;
930                 case 9:
931                         filp->f_op = &urandom_fops;
932                         break;
933                 case 11:
934                         filp->f_op = &kmsg_fops;
935                         break;
936 #ifdef CONFIG_CRASH_DUMP
937                 case 12:
938                         filp->f_op = &oldmem_fops;
939                         break;
940 #endif
941                 default:
942                         unlock_kernel();
943                         return -ENXIO;
944         }
945         if (filp->f_op && filp->f_op->open)
946                 ret = filp->f_op->open(inode,filp);
947         unlock_kernel();
948         return ret;
949 }
950
951 static const struct file_operations memory_fops = {
952         .open           = memory_open,  /* just a selector for the real open */
953 };
954
955 static const struct {
956         unsigned int            minor;
957         char                    *name;
958         umode_t                 mode;
959         const struct file_operations    *fops;
960 } devlist[] = { /* list of minor devices */
961         {1, "mem",     S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
962 #ifdef CONFIG_DEVKMEM
963         {2, "kmem",    S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops},
964 #endif
965         {3, "null",    S_IRUGO | S_IWUGO,           &null_fops},
966 #ifdef CONFIG_DEVPORT
967         {4, "port",    S_IRUSR | S_IWUSR | S_IRGRP, &port_fops},
968 #endif
969         {5, "zero",    S_IRUGO | S_IWUGO,           &zero_fops},
970         {7, "full",    S_IRUGO | S_IWUGO,           &full_fops},
971         {8, "random",  S_IRUGO | S_IWUSR,           &random_fops},
972         {9, "urandom", S_IRUGO | S_IWUSR,           &urandom_fops},
973         {11,"kmsg",    S_IRUGO | S_IWUSR,           &kmsg_fops},
974 #ifdef CONFIG_CRASH_DUMP
975         {12,"oldmem",    S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops},
976 #endif
977 };
978
979 static struct class *mem_class;
980
981 static int __init chr_dev_init(void)
982 {
983         int i;
984         int err;
985
986         err = bdi_init(&zero_bdi);
987         if (err)
988                 return err;
989
990         if (register_chrdev(MEM_MAJOR,"mem",&memory_fops))
991                 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
992
993         mem_class = class_create(THIS_MODULE, "mem");
994         for (i = 0; i < ARRAY_SIZE(devlist); i++)
995                 device_create(mem_class, NULL,
996                               MKDEV(MEM_MAJOR, devlist[i].minor), NULL,
997                               devlist[i].name);
998
999         return 0;
1000 }
1001
1002 fs_initcall(chr_dev_init);