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
  29 #include <asm/uaccess.h>
  30 #include <asm/io.h>
  31
  32 #ifdef CONFIG_IA64
  33 # include <linux/efi.h>
  34 #endif
  35
  36 #if defined(CONFIG_S390_TAPE) && defined(CONFIG_S390_TAPE_CHAR)
  37 extern void tapechar_init(void);
  38 #endif
  39
  40 /*
  41  * Architectures vary in how they handle caching for addresses
  42  * outside of main memory.
  43  *
  44  */
  45 static inline int uncached_access(struct file *file, unsigned long addr)
  46 {
  47 #if defined(__i386__)
  48         /*
  49          * On the PPro and successors, the MTRRs are used to set
  50          * memory types for physical addresses outside main memory,
  51          * so blindly setting PCD or PWT on those pages is wrong.
  52          * For Pentiums and earlier, the surround logic should disable
  53          * caching for the high addresses through the KEN pin, but
  54          * we maintain the tradition of paranoia in this code.
  55          */
  56         if (file->f_flags & O_SYNC)
  57                 return 1;
  58         return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) ||
  59                   test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) ||
  60                   test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) ||
  61                   test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) )
  62           && addr >= __pa(high_memory);
  63 #elif defined(__x86_64__)
  64         /*
  65          * This is broken because it can generate memory type aliases,
  66          * which can cause cache corruptions
  67          * But it is only available for root and we have to be bug-to-bug
  68          * compatible with i386.
  69          */
  70         if (file->f_flags & O_SYNC)
  71                 return 1;
  72         /* same behaviour as i386. PAT always set to cached and MTRRs control the
  73            caching behaviour.
  74            Hopefully a full PAT implementation will fix that soon. */
  75         return 0;
  76 #elif defined(CONFIG_IA64)
  77         /*
  78          * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
  79          */
  80         return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
  81 #elif defined(CONFIG_PPC64)
  82         /* On PPC64, we always do non-cacheable access to the IO hole and
  83          * cacheable elsewhere. Cache paradox can checkstop the CPU and
  84          * the high_memory heuristic below is wrong on machines with memory
  85          * above the IO hole... Ah, and of course, XFree86 doesn't pass
  86          * O_SYNC when mapping us to tap IO space. Surprised ?
  87          */
  88         return !page_is_ram(addr >> PAGE_SHIFT);
  89 #else
  90         /*
  91          * Accessing memory above the top the kernel knows about or through a file pointer
  92          * that was marked O_SYNC will be done non-cached.
  93          */
  94         if (file->f_flags & O_SYNC)
  95                 return 1;
  96         return addr >= __pa(high_memory);
  97 #endif
  98 }
  99
 100 #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
 101 static inline int valid_phys_addr_range(unsigned long addr, size_t *count)
 102 {
 103         unsigned long end_mem;
 104
 105         end_mem = __pa(high_memory);
 106         if (addr >= end_mem)
 107                 return 0;
 108
 109         if (*count > end_mem - addr)
 110                 *count = end_mem - addr;
 111
 112         return 1;
 113 }
 114 #endif
 115
 116 static inline int range_is_allowed(unsigned long from, unsigned long to)
 117 {
 118         unsigned long cursor;
 119
 120         cursor = from >> PAGE_SHIFT;
 121         while ((cursor << PAGE_SHIFT) < to) {
 122                 if (!devmem_is_allowed(cursor))
 123                         return 0;
 124                 cursor++;
 125         }
 126         return 1;
 127 }
 128 static ssize_t do_write_mem(void *p, unsigned long realp,
 129                             const char __user * buf, size_t count, loff_t *ppos)
 130 {
 131         ssize_t written;
 132         unsigned long copied;
 133
 134         written = 0;
 135 #if defined(__sparc__) || (defined(__mc68000__) && defined(CONFIG_MMU))
 136         /* we don't have page 0 mapped on sparc and m68k.. */
 137         if (realp < PAGE_SIZE) {
 138                 unsigned long sz = PAGE_SIZE-realp;
 139                 if (sz > count) sz = count;
 140                 /* Hmm. Do something? */
 141                 buf+=sz;
 142                 p+=sz;
 143                 count-=sz;
 144                 written+=sz;
 145         }
 146 #endif
 147         if (!range_is_allowed(realp, realp+count))
 148                 return -EPERM;
 149         copied = copy_from_user(p, buf, count);
 150         if (copied) {
 151                 ssize_t ret = written + (count - copied);
 152
 153                 if (ret)
 154                         return ret;
 155                 return -EFAULT;
 156         }
 157         written += count;
 158         *ppos += written;
 159         return written;
 160 }
 161
 162
 163 /*
 164  * This funcion reads the *physical* memory. The f_pos points directly to the
 165  * memory location.
 166  */
 167 static ssize_t read_mem(struct file * file, char __user * buf,
 168                         size_t count, loff_t *ppos)
 169 {
 170         unsigned long p = *ppos;
 171         ssize_t read;
 172
 173         if (!valid_phys_addr_range(p, &count))
 174                 return -EFAULT;
 175         read = 0;
 176 #if defined(__sparc__) || (defined(__mc68000__) && defined(CONFIG_MMU))
 177         /* we don't have page 0 mapped on sparc and m68k.. */
 178         if (p < PAGE_SIZE) {
 179                 unsigned long sz = PAGE_SIZE-p;
 180                 if (sz > count)
 181                         sz = count;
 182                 if (sz > 0) {
 183                         if (clear_user(buf, sz))
 184                                 return -EFAULT;
 185                         buf += sz;
 186                         p += sz;
 187                         count -= sz;
 188                         read += sz;
 189                 }
 190         }
 191 #endif
 192         if (!range_is_allowed(p, p+count))
 193                 return -EPERM;
 194         if (copy_to_user(buf, __va(p), count))
 195                 return -EFAULT;
 196         read += count;
 197         *ppos += read;
 198         return read;
 199 }
 200
 201 static ssize_t write_mem(struct file * file, const char __user * buf,
 202                          size_t count, loff_t *ppos)
 203 {
 204         unsigned long p = *ppos;
 205
 206         if (!valid_phys_addr_range(p, &count))
 207                 return -EFAULT;
 208         return do_write_mem(__va(p), p, buf, count, ppos);
 209 }
 210
 211 static int mmap_mem(struct file * file, struct vm_area_struct * vma)
 212 {
 213 #ifdef pgprot_noncached
 214         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 215         int uncached;
 216
 217         uncached = uncached_access(file, offset);
 218         if (uncached)
 219                 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 220 #endif
 221
 222         /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
 223         if (remap_pfn_range(vma,
 224                             vma->vm_start,
 225                             vma->vm_pgoff,
 226                             vma->vm_end-vma->vm_start,
 227                             vma->vm_page_prot))
 228                 return -EAGAIN;
 229         return 0;
 230 }
 231
 232 #ifdef CONFIG_CRASH_DUMP
 233 /*
 234  * Read memory corresponding to the old kernel.
 235  * If we are reading from the reserved section, which is
 236  * actually used by the current kernel, we just return zeroes.
 237  * Or if we are reading from the first 640k, we return from the
 238  * backed up area.
 239  */
 240 static ssize_t read_oldmem(struct file * file, char * buf,
 241                                 size_t count, loff_t *ppos)
 242 {
 243         unsigned long pfn;
 244         unsigned backup_start, backup_end, relocate_start;
 245         size_t read=0, csize;
 246
 247         backup_start = CRASH_BACKUP_BASE / PAGE_SIZE;
 248         backup_end = backup_start + (CRASH_BACKUP_SIZE / PAGE_SIZE);
 249         relocate_start = (CRASH_BACKUP_BASE + CRASH_BACKUP_SIZE) / PAGE_SIZE;
 250
 251         while(count) {
 252                 pfn = *ppos / PAGE_SIZE;
 253
 254                 csize = (count > PAGE_SIZE) ? PAGE_SIZE : count;
 255
 256                 /* Perform translation (see comment above) */
 257                 if ((pfn >= backup_start) && (pfn < backup_end)) {
 258                         if (clear_user(buf, csize)) {
 259                                 read = -EFAULT;
 260                                 goto done;
 261                         }
 262
 263                         goto copy_done;
 264                 } else if (pfn < (CRASH_RELOCATE_SIZE / PAGE_SIZE))
 265                         pfn += relocate_start;
 266
 267                 if (pfn > saved_max_pfn) {
 268                         read = 0;
 269                         goto done;
 270                 }
 271
 272                 if (copy_oldmem_page(pfn, buf, csize, 1)) {
 273                         read = -EFAULT;
 274                         goto done;
 275                 }
 276
 277 copy_done:
 278                 buf += csize;
 279                 *ppos += csize;
 280                 read += csize;
 281                 count -= csize;
 282         }
 283 done:
 284         return read;
 285 }
 286 #endif
 287
 288 extern long vread(char *buf, char *addr, unsigned long count);
 289 extern long vwrite(char *buf, char *addr, unsigned long count);
 290
 291 /*
 292  * This function reads the *virtual* memory as seen by the kernel.
 293  */
 294 static ssize_t read_kmem(struct file *file, char __user *buf,
 295                          size_t count, loff_t *ppos)
 296 {
 297         unsigned long p = *ppos;
 298         ssize_t read = 0;
 299         ssize_t virtr = 0;
 300         char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
 301
 302         return -EPERM;
 303
 304         if (p < (unsigned long) high_memory) {
 305                 read = count;
 306                 if (count > (unsigned long) high_memory - p)
 307                         read = (unsigned long) high_memory - p;
 308
 309 #if defined(__sparc__) || (defined(__mc68000__) && defined(CONFIG_MMU))
 310                 /* we don't have page 0 mapped on sparc and m68k.. */
 311                 if (p < PAGE_SIZE && read > 0) {
 312                         size_t tmp = PAGE_SIZE - p;
 313                         if (tmp > read) tmp = read;
 314                         if (clear_user(buf, tmp))
 315                                 return -EFAULT;
 316                         buf += tmp;
 317                         p += tmp;
 318                         read -= tmp;
 319                         count -= tmp;
 320                 }
 321 #endif
 322                 if (copy_to_user(buf, (char *)p, read))
 323                         return -EFAULT;
 324                 p += read;
 325                 buf += read;
 326                 count -= read;
 327         }
 328
 329         if (count > 0) {
 330                 kbuf = (char *)__get_free_page(GFP_KERNEL);
 331                 if (!kbuf)
 332                         return -ENOMEM;
 333                 while (count > 0) {
 334                         int len = count;
 335
 336                         if (len > PAGE_SIZE)
 337                                 len = PAGE_SIZE;
 338                         len = vread(kbuf, (char *)p, len);
 339                         if (!len)
 340                                 break;
 341                         if (copy_to_user(buf, kbuf, len)) {
 342                                 free_page((unsigned long)kbuf);
 343                                 return -EFAULT;
 344                         }
 345                         count -= len;
 346                         buf += len;
 347                         virtr += len;
 348                         p += len;
 349                 }
 350                 free_page((unsigned long)kbuf);
 351         }
 352         *ppos = p;
 353         return virtr + read;
 354 }
 355
 356 #if defined(CONFIG_ISA) || !defined(__mc68000__)
 357 static ssize_t read_port(struct file * file, char __user * buf,
 358                          size_t count, loff_t *ppos)
 359 {
 360         unsigned long i = *ppos;
 361         char __user *tmp = buf;
 362
 363         if (verify_area(VERIFY_WRITE,buf,count))
 364                 return -EFAULT;
 365         while (count-- > 0 && i < 65536) {
 366                 if (__put_user(inb(i),tmp) < 0)
 367                         return -EFAULT;
 368                 i++;
 369                 tmp++;
 370         }
 371         *ppos = i;
 372         return tmp-buf;
 373 }
 374
 375 static ssize_t write_port(struct file * file, const char __user * buf,
 376                           size_t count, loff_t *ppos)
 377 {
 378         unsigned long i = *ppos;
 379         const char __user * tmp = buf;
 380
 381         if (verify_area(VERIFY_READ,buf,count))
 382                 return -EFAULT;
 383         while (count-- > 0 && i < 65536) {
 384                 char c;
 385                 if (__get_user(c, tmp))
 386                         return -EFAULT;
 387                 outb(c,i);
 388                 i++;
 389                 tmp++;
 390         }
 391         *ppos = i;
 392         return tmp-buf;
 393 }
 394 #endif
 395
 396 static ssize_t read_null(struct file * file, char __user * buf,
 397                          size_t count, loff_t *ppos)
 398 {
 399         return 0;
 400 }
 401
 402 static ssize_t write_null(struct file * file, const char __user * buf,
 403                           size_t count, loff_t *ppos)
 404 {
 405         return count;
 406 }
 407
 408 #ifdef CONFIG_MMU
 409 /*
 410  * For fun, we are using the MMU for this.
 411  */
 412 static inline size_t read_zero_pagealigned(char __user * buf, size_t size)
 413 {
 414         struct mm_struct *mm;
 415         struct vm_area_struct * vma;
 416         unsigned long addr=(unsigned long)buf;
 417
 418         mm = current->mm;
 419         /* Oops, this was forgotten before. -ben */
 420         down_read(&mm->mmap_sem);
 421
 422         /* For private mappings, just map in zero pages. */
 423         for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
 424                 unsigned long count;
 425
 426                 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0)
 427                         goto out_up;
 428                 if (vma->vm_flags & (VM_SHARED | VM_HUGETLB))
 429                         break;
 430                 count = vma->vm_end - addr;
 431                 if (count > size)
 432                         count = size;
 433
 434                 zap_page_range(vma, addr, count, NULL);
 435                 zeromap_page_range(vma, addr, count, PAGE_COPY);
 436
 437                 size -= count;
 438                 buf += count;
 439                 addr += count;
 440                 if (size == 0)
 441                         goto out_up;
 442         }
 443
 444         up_read(&mm->mmap_sem);
 445
 446         /* The shared case is hard. Let's do the conventional zeroing. */
 447         do {
 448                 unsigned long unwritten = clear_user(buf, PAGE_SIZE);
 449                 if (unwritten)
 450                         return size + unwritten - PAGE_SIZE;
 451                 cond_resched();
 452                 buf += PAGE_SIZE;
 453                 size -= PAGE_SIZE;
 454         } while (size);
 455
 456         return size;
 457 out_up:
 458         up_read(&mm->mmap_sem);
 459         return size;
 460 }
 461
 462 static ssize_t read_zero(struct file * file, char __user * buf,
 463                          size_t count, loff_t *ppos)
 464 {
 465         unsigned long left, unwritten, written = 0;
 466
 467         if (!count)
 468                 return 0;
 469
 470         if (!access_ok(VERIFY_WRITE, buf, count))
 471                 return -EFAULT;
 472
 473         left = count;
 474
 475         /* do we want to be clever? Arbitrary cut-off */
 476         if (count >= PAGE_SIZE*4) {
 477                 unsigned long partial;
 478
 479                 /* How much left of the page? */
 480                 partial = (PAGE_SIZE-1) & -(unsigned long) buf;
 481                 unwritten = clear_user(buf, partial);
 482                 written = partial - unwritten;
 483                 if (unwritten)
 484                         goto out;
 485                 left -= partial;
 486                 buf += partial;
 487                 unwritten = read_zero_pagealigned(buf, left & PAGE_MASK);
 488                 written += (left & PAGE_MASK) - unwritten;
 489                 if (unwritten)
 490                         goto out;
 491                 buf += left & PAGE_MASK;
 492                 left &= ~PAGE_MASK;
 493         }
 494         unwritten = clear_user(buf, left);
 495         written += left - unwritten;
 496 out:
 497         return written ? written : -EFAULT;
 498 }
 499
 500 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
 501 {
 502         if (vma->vm_flags & VM_SHARED)
 503                 return shmem_zero_setup(vma);
 504         if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot))
 505                 return -EAGAIN;
 506         return 0;
 507 }
 508 #else /* CONFIG_MMU */
 509 static ssize_t read_zero(struct file * file, char * buf,
 510                          size_t count, loff_t *ppos)
 511 {
 512         size_t todo = count;
 513
 514         while (todo) {
 515                 size_t chunk = todo;
 516
 517                 if (chunk > 4096)
 518                         chunk = 4096;   /* Just for latency reasons */
 519                 if (clear_user(buf, chunk))
 520                         return -EFAULT;
 521                 buf += chunk;
 522                 todo -= chunk;
 523                 cond_resched();
 524         }
 525         return count;
 526 }
 527
 528 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
 529 {
 530         return -ENOSYS;
 531 }
 532 #endif /* CONFIG_MMU */
 533
 534 static ssize_t write_full(struct file * file, const char __user * buf,
 535                           size_t count, loff_t *ppos)
 536 {
 537         return -ENOSPC;
 538 }
 539
 540 /*
 541  * Special lseek() function for /dev/null and /dev/zero.  Most notably, you
 542  * can fopen() both devices with "a" now.  This was previously impossible.
 543  * -- SRB.
 544  */
 545
 546 static loff_t null_lseek(struct file * file, loff_t offset, int orig)
 547 {
 548         return file->f_pos = 0;
 549 }
 550
 551 /*
 552  * The memory devices use the full 32/64 bits of the offset, and so we cannot
 553  * check against negative addresses: they are ok. The return value is weird,
 554  * though, in that case (0).
 555  *
 556  * also note that seeking relative to the "end of file" isn't supported:
 557  * it has no meaning, so it returns -EINVAL.
 558  */
 559 static loff_t memory_lseek(struct file * file, loff_t offset, int orig)
 560 {
 561         loff_t ret;
 562
 563         down(&file->f_dentry->d_inode->i_sem);
 564         switch (orig) {
 565                 case 0:
 566                         file->f_pos = offset;
 567                         ret = file->f_pos;
 568                         force_successful_syscall_return();
 569                         break;
 570                 case 1:
 571                         file->f_pos += offset;
 572                         ret = file->f_pos;
 573                         force_successful_syscall_return();
 574                         break;
 575                 default:
 576                         ret = -EINVAL;
 577         }
 578         up(&file->f_dentry->d_inode->i_sem);
 579         return ret;
 580 }
 581
 582 static int open_port(struct inode * inode, struct file * filp)
 583 {
 584         return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
 585 }
 586
 587 #define mmap_kmem       mmap_mem
 588 #define zero_lseek      null_lseek
 589 #define full_lseek      null_lseek
 590 #define write_zero      write_null
 591 #define read_full       read_zero
 592 #define open_mem        open_port
 593 #define open_kmem       open_mem
 594 #define open_oldmem     open_mem
 595
 596 static struct file_operations mem_fops = {
 597         .llseek         = memory_lseek,
 598         .read           = read_mem,
 599         .write          = write_mem,
 600         .mmap           = mmap_mem,
 601         .open           = open_mem,
 602 };
 603
 604 static struct file_operations kmem_fops = {
 605         .llseek         = memory_lseek,
 606         .read           = read_kmem,
 607         .mmap           = mmap_kmem,
 608         .open           = open_kmem,
 609 };
 610
 611 static struct file_operations null_fops = {
 612         .llseek         = null_lseek,
 613         .read           = read_null,
 614         .write          = write_null,
 615 };
 616
 617 #if defined(CONFIG_ISA) || !defined(__mc68000__)
 618 static struct file_operations port_fops = {
 619         .llseek         = memory_lseek,
 620         .read           = read_port,
 621         .write          = write_port,
 622         .open           = open_port,
 623 };
 624 #endif
 625
 626 static struct file_operations zero_fops = {
 627         .llseek         = zero_lseek,
 628         .read           = read_zero,
 629         .write          = write_zero,
 630         .mmap           = mmap_zero,
 631 };
 632
 633 static struct file_operations full_fops = {
 634         .llseek         = full_lseek,
 635         .read           = read_full,
 636         .write          = write_full,
 637 };
 638
 639 #ifdef CONFIG_CRASH_DUMP
 640 static struct file_operations oldmem_fops = {
 641         .read   = read_oldmem,
 642         .open   = open_oldmem,
 643 };
 644 #endif
 645
 646 static ssize_t kmsg_write(struct file * file, const char __user * buf,
 647                           size_t count, loff_t *ppos)
 648 {
 649         char *tmp;
 650         int ret;
 651
 652         tmp = kmalloc(count + 1, GFP_KERNEL);
 653         if (tmp == NULL)
 654                 return -ENOMEM;
 655         ret = -EFAULT;
 656         if (!copy_from_user(tmp, buf, count)) {
 657                 tmp[count] = 0;
 658                 ret = printk("%s", tmp);
 659         }
 660         kfree(tmp);
 661         return ret;
 662 }
 663
 664 static struct file_operations kmsg_fops = {
 665         .write =        kmsg_write,
 666 };
 667
 668 static int memory_open(struct inode * inode, struct file * filp)
 669 {
 670         switch (iminor(inode)) {
 671                 case 1:
 672                         filp->f_op = &mem_fops;
 673                         break;
 674                 case 2:
 675                         filp->f_op = &kmem_fops;
 676                         break;
 677                 case 3:
 678                         filp->f_op = &null_fops;
 679                         break;
 680 #if defined(CONFIG_ISA) || !defined(__mc68000__)
 681                 case 4:
 682                         filp->f_op = &port_fops;
 683                         break;
 684 #endif
 685                 case 5:
 686                         filp->f_op = &zero_fops;
 687                         break;
 688                 case 7:
 689                         filp->f_op = &full_fops;
 690                         break;
 691                 case 8:
 692                         filp->f_op = &random_fops;
 693                         break;
 694                 case 9:
 695                         filp->f_op = &urandom_fops;
 696                         break;
 697                 case 11:
 698                         filp->f_op = &kmsg_fops;
 699                         break;
 700 #ifdef CONFIG_CRASH_DUMP
 701                 case 12:
 702                         filp->f_op = &oldmem_fops;
 703                         break;
 704 #endif
 705                 default:
 706                         return -ENXIO;
 707         }
 708         if (filp->f_op && filp->f_op->open)
 709                 return filp->f_op->open(inode,filp);
 710         return 0;
 711 }
 712
 713 static struct file_operations memory_fops = {
 714         .open           = memory_open,  /* just a selector for the real open */
 715 };
 716
 717 static const struct {
 718         unsigned int            minor;
 719         char                    *name;
 720         umode_t                 mode;
 721         struct file_operations  *fops;
 722 } devlist[] = { /* list of minor devices */
 723         {1, "mem",     S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
 724         {3, "null",    S_IRUGO | S_IWUGO,           &null_fops},
 725 #if defined(CONFIG_ISA) || !defined(__mc68000__)
 726         {4, "port",    S_IRUSR | S_IWUSR | S_IRGRP, &port_fops},
 727 #endif
 728         {5, "zero",    S_IRUGO | S_IWUGO,           &zero_fops},
 729         {7, "full",    S_IRUGO | S_IWUGO,           &full_fops},
 730         {8, "random",  S_IRUGO | S_IWUSR,           &random_fops},
 731         {9, "urandom", S_IRUGO | S_IWUSR,           &urandom_fops},
 732         {11,"kmsg",    S_IRUGO | S_IWUSR,           &kmsg_fops},
 733 #ifdef CONFIG_CRASH_DUMP
 734         {12,"oldmem",    S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops},
 735 #endif
 736 };
 737
 738 static struct class_simple *mem_class;
 739
 740 static int __init chr_dev_init(void)
 741 {
 742         int i;
 743
 744         if (register_chrdev(MEM_MAJOR,"mem",&memory_fops))
 745                 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
 746
 747         mem_class = class_simple_create(THIS_MODULE, "mem");
 748         for (i = 0; i < ARRAY_SIZE(devlist); i++) {
 749                 class_simple_device_add(mem_class,
 750                                         MKDEV(MEM_MAJOR, devlist[i].minor),
 751                                         NULL, devlist[i].name);
 752                 devfs_mk_cdev(MKDEV(MEM_MAJOR, devlist[i].minor),
 753                                 S_IFCHR | devlist[i].mode, devlist[i].name);
 754         }
 755
 756         return 0;
 757 }
 758
 759 fs_initcall(chr_dev_init);