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
  27 #include <asm/uaccess.h>
  28 #include <asm/io.h>
  29
  30 #ifdef CONFIG_IA64
  31 # include <linux/efi.h>
  32 #endif
  33
  34 #ifdef CONFIG_FB
  35 extern void fbmem_init(void);
  36 #endif
  37 #if defined(CONFIG_S390_TAPE) && defined(CONFIG_S390_TAPE_CHAR)
  38 extern void tapechar_init(void);
  39 #endif
  40
  41 /*
  42  * Architectures vary in how they handle caching for addresses
  43  * outside of main memory.
  44  *
  45  */
  46 static inline int uncached_access(struct file *file, unsigned long addr)
  47 {
  48 #if defined(__i386__)
  49         /*
  50          * On the PPro and successors, the MTRRs are used to set
  51          * memory types for physical addresses outside main memory,
  52          * so blindly setting PCD or PWT on those pages is wrong.
  53          * For Pentiums and earlier, the surround logic should disable
  54          * caching for the high addresses through the KEN pin, but
  55          * we maintain the tradition of paranoia in this code.
  56          */
  57         if (file->f_flags & O_SYNC)
  58                 return 1;
  59         return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) ||
  60                   test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) ||
  61                   test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) ||
  62                   test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) )
  63           && addr >= __pa(high_memory);
  64 #elif defined(__x86_64__)
  65         /*
  66          * This is broken because it can generate memory type aliases,
  67          * which can cause cache corruptions
  68          * But it is only available for root and we have to be bug-to-bug
  69          * compatible with i386.
  70          */
  71         if (file->f_flags & O_SYNC)
  72                 return 1;
  73         /* same behaviour as i386. PAT always set to cached and MTRRs control the
  74            caching behaviour.
  75            Hopefully a full PAT implementation will fix that soon. */
  76         return 0;
  77 #elif defined(CONFIG_IA64)
  78         /*
  79          * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
  80          */
  81         return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
  82 #elif defined(CONFIG_PPC64)
  83         /* On PPC64, we always do non-cacheable access to the IO hole and
  84          * cacheable elsewhere. Cache paradox can checkstop the CPU and
  85          * the high_memory heuristic below is wrong on machines with memory
  86          * above the IO hole... Ah, and of course, XFree86 doesn't pass
  87          * O_SYNC when mapping us to tap IO space. Surprised ?
  88          */
  89         return !page_is_ram(addr);
  90 #else
  91         /*
  92          * Accessing memory above the top the kernel knows about or through a file pointer
  93          * that was marked O_SYNC will be done non-cached.
  94          */
  95         if (file->f_flags & O_SYNC)
  96                 return 1;
  97         return addr >= __pa(high_memory);
  98 #endif
  99 }
 100
 101 #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
 102 static inline int valid_phys_addr_range(unsigned long addr, size_t *count)
 103 {
 104         unsigned long end_mem;
 105
 106         end_mem = __pa(high_memory);
 107         if (addr >= end_mem)
 108                 return 0;
 109
 110         if (*count > end_mem - addr)
 111                 *count = end_mem - addr;
 112
 113         return 1;
 114 }
 115 #endif
 116
 117 extern int page_is_ram(unsigned long pagenr);
 118
 119 static inline int page_is_allowed(unsigned long pagenr)
 120 {
 121  #ifdef CONFIG_X86
 122         if (pagenr <= 256)
 123                 return 1;
 124         if (!page_is_ram(pagenr))
 125                 return 1;
 126         printk("Access to 0x%lx by %s denied \n", pagenr << PAGE_SHIFT, current->comm);
 127         return 0;
 128  #else
 129        return 1;
 130  #endif
 131 }
 132
 133 static inline int range_is_allowed(unsigned long from, unsigned long to)
 134 {
 135         unsigned long cursor;
 136
 137         cursor = from >> PAGE_SHIFT;
 138         while ( (cursor << PAGE_SHIFT) < to) {
 139                 if (!page_is_allowed(cursor))
 140                         return 0;
 141                 cursor++;
 142         }
 143         return 1;
 144 }
 145 static ssize_t do_write_mem(void *p, unsigned long realp,
 146                             const char __user * buf, size_t count, loff_t *ppos)
 147 {
 148         ssize_t written;
 149         unsigned long copied;
 150
 151         written = 0;
 152 #if defined(__sparc__) || (defined(__mc68000__) && defined(CONFIG_MMU))
 153         /* we don't have page 0 mapped on sparc and m68k.. */
 154         if (realp < PAGE_SIZE) {
 155                 unsigned long sz = PAGE_SIZE-realp;
 156                 if (sz > count) sz = count;
 157                 /* Hmm. Do something? */
 158                 buf+=sz;
 159                 p+=sz;
 160                 count-=sz;
 161                 written+=sz;
 162         }
 163 #endif
 164         if (!range_is_allowed(realp, realp+count))
 165                 return -EFAULT;
 166         copied = copy_from_user(p, buf, count);
 167         if (copied) {
 168                 ssize_t ret = written + (count - copied);
 169
 170                 if (ret)
 171                         return ret;
 172                 return -EFAULT;
 173         }
 174         written += count;
 175         *ppos += written;
 176         return written;
 177 }
 178
 179
 180 /*
 181  * This funcion reads the *physical* memory. The f_pos points directly to the
 182  * memory location.
 183  */
 184 static ssize_t read_mem(struct file * file, char __user * buf,
 185                         size_t count, loff_t *ppos)
 186 {
 187         unsigned long p = *ppos;
 188         ssize_t read;
 189
 190         if (!valid_phys_addr_range(p, &count))
 191                 return -EFAULT;
 192         read = 0;
 193 #if defined(__sparc__) || (defined(__mc68000__) && defined(CONFIG_MMU))
 194         /* we don't have page 0 mapped on sparc and m68k.. */
 195         if (p < PAGE_SIZE) {
 196                 unsigned long sz = PAGE_SIZE-p;
 197                 if (sz > count)
 198                         sz = count;
 199                 if (sz > 0) {
 200                         if (clear_user(buf, sz))
 201                                 return -EFAULT;
 202                         buf += sz;
 203                         p += sz;
 204                         count -= sz;
 205                         read += sz;
 206                 }
 207         }
 208 #endif
 209         if (!range_is_allowed(p, p+count))
 210                 return -EFAULT;
 211         if (copy_to_user(buf, __va(p), count))
 212                 return -EFAULT;
 213         read += count;
 214         *ppos += read;
 215         return read;
 216 }
 217
 218 static ssize_t write_mem(struct file * file, const char __user * buf,
 219                          size_t count, loff_t *ppos)
 220 {
 221         unsigned long p = *ppos;
 222
 223         if (!valid_phys_addr_range(p, &count))
 224                 return -EFAULT;
 225         return do_write_mem(__va(p), p, buf, count, ppos);
 226 }
 227
 228 static int mmap_mem(struct file * file, struct vm_area_struct * vma)
 229 {
 230         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 231         int uncached;
 232         unsigned long cursor;
 233
 234         uncached = uncached_access(file, offset);
 235 #ifdef pgprot_noncached
 236         if (uncached)
 237                 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 238 #endif
 239
 240         /* Don't try to swap out physical pages.. */
 241         vma->vm_flags |= VM_RESERVED;
 242
 243         /*
 244          * Don't dump addresses that are not real memory to a core file.
 245          */
 246         if (uncached)
 247                 vma->vm_flags |= VM_IO;
 248
 249         cursor = vma->vm_pgoff;
 250         while ((cursor << PAGE_SHIFT) < offset + vma->vm_end-vma->vm_start) {
 251                 if (!page_is_allowed(cursor))
 252                         return -EFAULT;
 253                 cursor++;
 254         }
 255
 256         if (remap_page_range(vma, vma->vm_start, offset, vma->vm_end-vma->vm_start,
 257                              vma->vm_page_prot))
 258                 return -EAGAIN;
 259         return 0;
 260 }
 261
 262 extern long vread(char *buf, char *addr, unsigned long count);
 263 extern long vwrite(char *buf, char *addr, unsigned long count);
 264
 265 /*
 266  * This function reads the *virtual* memory as seen by the kernel.
 267  */
 268 static ssize_t read_kmem(struct file *file, char __user *buf,
 269                          size_t count, loff_t *ppos)
 270 {
 271         unsigned long p = *ppos;
 272         ssize_t read = 0;
 273         ssize_t virtr = 0;
 274         char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
 275
 276         return -EPERM;
 277
 278         if (p < (unsigned long) high_memory) {
 279                 read = count;
 280                 if (count > (unsigned long) high_memory - p)
 281                         read = (unsigned long) high_memory - p;
 282
 283 #if defined(__sparc__) || (defined(__mc68000__) && defined(CONFIG_MMU))
 284                 /* we don't have page 0 mapped on sparc and m68k.. */
 285                 if (p < PAGE_SIZE && read > 0) {
 286                         size_t tmp = PAGE_SIZE - p;
 287                         if (tmp > read) tmp = read;
 288                         if (clear_user(buf, tmp))
 289                                 return -EFAULT;
 290                         buf += tmp;
 291                         p += tmp;
 292                         read -= tmp;
 293                         count -= tmp;
 294                 }
 295 #endif
 296                 if (copy_to_user(buf, (char *)p, read))
 297                         return -EFAULT;
 298                 p += read;
 299                 buf += read;
 300                 count -= read;
 301         }
 302
 303         if (count > 0) {
 304                 kbuf = (char *)__get_free_page(GFP_KERNEL);
 305                 if (!kbuf)
 306                         return -ENOMEM;
 307                 while (count > 0) {
 308                         int len = count;
 309
 310                         if (len > PAGE_SIZE)
 311                                 len = PAGE_SIZE;
 312                         len = vread(kbuf, (char *)p, len);
 313                         if (!len)
 314                                 break;
 315                         if (copy_to_user(buf, kbuf, len)) {
 316                                 free_page((unsigned long)kbuf);
 317                                 return -EFAULT;
 318                         }
 319                         count -= len;
 320                         buf += len;
 321                         virtr += len;
 322                         p += len;
 323                 }
 324                 free_page((unsigned long)kbuf);
 325         }
 326         *ppos = p;
 327         return virtr + read;
 328 }
 329
 330 /*
 331  * This function writes to the *virtual* memory as seen by the kernel.
 332  */
 333 static ssize_t write_kmem(struct file * file, const char __user * buf,
 334                           size_t count, loff_t *ppos)
 335 {
 336         unsigned long p = *ppos;
 337         ssize_t wrote = 0;
 338         ssize_t virtr = 0;
 339         ssize_t written;
 340         char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
 341
 342         return -EPERM;
 343
 344         if (p < (unsigned long) high_memory) {
 345
 346                 wrote = count;
 347                 if (count > (unsigned long) high_memory - p)
 348                         wrote = (unsigned long) high_memory - p;
 349
 350                 written = do_write_mem((void*)p, p, buf, wrote, ppos);
 351                 if (written != wrote)
 352                         return written;
 353                 wrote = written;
 354                 p += wrote;
 355                 buf += wrote;
 356                 count -= wrote;
 357         }
 358
 359         if (count > 0) {
 360                 kbuf = (char *)__get_free_page(GFP_KERNEL);
 361                 if (!kbuf)
 362                         return wrote ? wrote : -ENOMEM;
 363                 while (count > 0) {
 364                         int len = count;
 365
 366                         if (len > PAGE_SIZE)
 367                                 len = PAGE_SIZE;
 368                         if (len) {
 369                                 written = copy_from_user(kbuf, buf, len);
 370                                 if (written) {
 371                                         ssize_t ret;
 372
 373                                         free_page((unsigned long)kbuf);
 374                                         ret = wrote + virtr + (len - written);
 375                                         return ret ? ret : -EFAULT;
 376                                 }
 377                         }
 378                         len = vwrite(kbuf, (char *)p, len);
 379                         count -= len;
 380                         buf += len;
 381                         virtr += len;
 382                         p += len;
 383                 }
 384                 free_page((unsigned long)kbuf);
 385         }
 386
 387         *ppos = p;
 388         return virtr + wrote;
 389 }
 390
 391 #if defined(CONFIG_ISA) || !defined(__mc68000__)
 392 static ssize_t read_port(struct file * file, char __user * buf,
 393                          size_t count, loff_t *ppos)
 394 {
 395         unsigned long i = *ppos;
 396         char __user *tmp = buf;
 397
 398         if (verify_area(VERIFY_WRITE,buf,count))
 399                 return -EFAULT;
 400         while (count-- > 0 && i < 65536) {
 401                 if (__put_user(inb(i),tmp) < 0)
 402                         return -EFAULT;
 403                 i++;
 404                 tmp++;
 405         }
 406         *ppos = i;
 407         return tmp-buf;
 408 }
 409
 410 static ssize_t write_port(struct file * file, const char __user * buf,
 411                           size_t count, loff_t *ppos)
 412 {
 413         unsigned long i = *ppos;
 414         const char __user * tmp = buf;
 415
 416         if (verify_area(VERIFY_READ,buf,count))
 417                 return -EFAULT;
 418         while (count-- > 0 && i < 65536) {
 419                 char c;
 420                 if (__get_user(c, tmp))
 421                         return -EFAULT;
 422                 outb(c,i);
 423                 i++;
 424                 tmp++;
 425         }
 426         *ppos = i;
 427         return tmp-buf;
 428 }
 429 #endif
 430
 431 static ssize_t read_null(struct file * file, char __user * buf,
 432                          size_t count, loff_t *ppos)
 433 {
 434         return 0;
 435 }
 436
 437 static ssize_t write_null(struct file * file, const char __user * buf,
 438                           size_t count, loff_t *ppos)
 439 {
 440         return count;
 441 }
 442
 443 #ifdef CONFIG_MMU
 444 /*
 445  * For fun, we are using the MMU for this.
 446  */
 447 static inline size_t read_zero_pagealigned(char __user * buf, size_t size)
 448 {
 449         struct mm_struct *mm;
 450         struct vm_area_struct * vma;
 451         unsigned long addr=(unsigned long)buf;
 452
 453         mm = current->mm;
 454         /* Oops, this was forgotten before. -ben */
 455         down_read(&mm->mmap_sem);
 456
 457         /* For private mappings, just map in zero pages. */
 458         for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
 459                 unsigned long count;
 460
 461                 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0)
 462                         goto out_up;
 463                 if (vma->vm_flags & VM_SHARED)
 464                         break;
 465                 count = vma->vm_end - addr;
 466                 if (count > size)
 467                         count = size;
 468
 469                 zap_page_range(vma, addr, count, NULL);
 470                 zeromap_page_range(vma, addr, count, PAGE_COPY);
 471
 472                 size -= count;
 473                 buf += count;
 474                 addr += count;
 475                 if (size == 0)
 476                         goto out_up;
 477         }
 478
 479         up_read(&mm->mmap_sem);
 480
 481         /* The shared case is hard. Let's do the conventional zeroing. */
 482         do {
 483                 unsigned long unwritten = clear_user(buf, PAGE_SIZE);
 484                 if (unwritten)
 485                         return size + unwritten - PAGE_SIZE;
 486                 cond_resched();
 487                 buf += PAGE_SIZE;
 488                 size -= PAGE_SIZE;
 489         } while (size);
 490
 491         return size;
 492 out_up:
 493         up_read(&mm->mmap_sem);
 494         return size;
 495 }
 496
 497 static ssize_t read_zero(struct file * file, char __user * buf,
 498                          size_t count, loff_t *ppos)
 499 {
 500         unsigned long left, unwritten, written = 0;
 501
 502         if (!count)
 503                 return 0;
 504
 505         if (!access_ok(VERIFY_WRITE, buf, count))
 506                 return -EFAULT;
 507
 508         left = count;
 509
 510         /* do we want to be clever? Arbitrary cut-off */
 511         if (count >= PAGE_SIZE*4) {
 512                 unsigned long partial;
 513
 514                 /* How much left of the page? */
 515                 partial = (PAGE_SIZE-1) & -(unsigned long) buf;
 516                 unwritten = clear_user(buf, partial);
 517                 written = partial - unwritten;
 518                 if (unwritten)
 519                         goto out;
 520                 left -= partial;
 521                 buf += partial;
 522                 unwritten = read_zero_pagealigned(buf, left & PAGE_MASK);
 523                 written += (left & PAGE_MASK) - unwritten;
 524                 if (unwritten)
 525                         goto out;
 526                 buf += left & PAGE_MASK;
 527                 left &= ~PAGE_MASK;
 528         }
 529         unwritten = clear_user(buf, left);
 530         written += left - unwritten;
 531 out:
 532         return written ? written : -EFAULT;
 533 }
 534
 535 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
 536 {
 537         if (vma->vm_flags & VM_SHARED)
 538                 return shmem_zero_setup(vma);
 539         if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot))
 540                 return -EAGAIN;
 541         return 0;
 542 }
 543 #else /* CONFIG_MMU */
 544 static ssize_t read_zero(struct file * file, char * buf,
 545                          size_t count, loff_t *ppos)
 546 {
 547         size_t todo = count;
 548
 549         while (todo) {
 550                 size_t chunk = todo;
 551
 552                 if (chunk > 4096)
 553                         chunk = 4096;   /* Just for latency reasons */
 554                 if (clear_user(buf, chunk))
 555                         return -EFAULT;
 556                 buf += chunk;
 557                 todo -= chunk;
 558                 cond_resched();
 559         }
 560         return count;
 561 }
 562
 563 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
 564 {
 565         return -ENOSYS;
 566 }
 567 #endif /* CONFIG_MMU */
 568
 569 static ssize_t write_full(struct file * file, const char __user * buf,
 570                           size_t count, loff_t *ppos)
 571 {
 572         return -ENOSPC;
 573 }
 574
 575 /*
 576  * Special lseek() function for /dev/null and /dev/zero.  Most notably, you
 577  * can fopen() both devices with "a" now.  This was previously impossible.
 578  * -- SRB.
 579  */
 580
 581 static loff_t null_lseek(struct file * file, loff_t offset, int orig)
 582 {
 583         return file->f_pos = 0;
 584 }
 585
 586 /*
 587  * The memory devices use the full 32/64 bits of the offset, and so we cannot
 588  * check against negative addresses: they are ok. The return value is weird,
 589  * though, in that case (0).
 590  *
 591  * also note that seeking relative to the "end of file" isn't supported:
 592  * it has no meaning, so it returns -EINVAL.
 593  */
 594 static loff_t memory_lseek(struct file * file, loff_t offset, int orig)
 595 {
 596         loff_t ret;
 597
 598         down(&file->f_dentry->d_inode->i_sem);
 599         switch (orig) {
 600                 case 0:
 601                         file->f_pos = offset;
 602                         ret = file->f_pos;
 603                         force_successful_syscall_return();
 604                         break;
 605                 case 1:
 606                         file->f_pos += offset;
 607                         ret = file->f_pos;
 608                         force_successful_syscall_return();
 609                         break;
 610                 default:
 611                         ret = -EINVAL;
 612         }
 613         up(&file->f_dentry->d_inode->i_sem);
 614         return ret;
 615 }
 616
 617 static int open_port(struct inode * inode, struct file * filp)
 618 {
 619         return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
 620 }
 621
 622 #define mmap_kmem       mmap_mem
 623 #define zero_lseek      null_lseek
 624 #define full_lseek      null_lseek
 625 #define write_zero      write_null
 626 #define read_full       read_zero
 627 #define open_mem        open_port
 628 #define open_kmem       open_mem
 629
 630 static struct file_operations mem_fops = {
 631         .llseek         = memory_lseek,
 632         .read           = read_mem,
 633         .write          = write_mem,
 634         .mmap           = mmap_mem,
 635         .open           = open_mem,
 636 };
 637
 638 static struct file_operations kmem_fops = {
 639         .llseek         = memory_lseek,
 640         .read           = read_kmem,
 641         .write          = write_kmem,
 642         .mmap           = mmap_kmem,
 643         .open           = open_kmem,
 644 };
 645
 646 static struct file_operations null_fops = {
 647         .llseek         = null_lseek,
 648         .read           = read_null,
 649         .write          = write_null,
 650 };
 651
 652 #if defined(CONFIG_ISA) || !defined(__mc68000__)
 653 static struct file_operations port_fops = {
 654         .llseek         = memory_lseek,
 655         .read           = read_port,
 656         .write          = write_port,
 657         .open           = open_port,
 658 };
 659 #endif
 660
 661 static struct file_operations zero_fops = {
 662         .llseek         = zero_lseek,
 663         .read           = read_zero,
 664         .write          = write_zero,
 665         .mmap           = mmap_zero,
 666 };
 667
 668 static struct file_operations full_fops = {
 669         .llseek         = full_lseek,
 670         .read           = read_full,
 671         .write          = write_full,
 672 };
 673
 674 static ssize_t kmsg_write(struct file * file, const char __user * buf,
 675                           size_t count, loff_t *ppos)
 676 {
 677         char *tmp;
 678         int ret;
 679
 680         tmp = kmalloc(count + 1, GFP_KERNEL);
 681         if (tmp == NULL)
 682                 return -ENOMEM;
 683         ret = -EFAULT;
 684         if (!copy_from_user(tmp, buf, count)) {
 685                 tmp[count] = 0;
 686                 ret = printk("%s", tmp);
 687         }
 688         kfree(tmp);
 689         return ret;
 690 }
 691
 692 static struct file_operations kmsg_fops = {
 693         .write =        kmsg_write,
 694 };
 695
 696 static int memory_open(struct inode * inode, struct file * filp)
 697 {
 698         switch (iminor(inode)) {
 699                 case 1:
 700                         filp->f_op = &mem_fops;
 701                         break;
 702                 case 2:
 703                         filp->f_op = &kmem_fops;
 704                         break;
 705                 case 3:
 706                         filp->f_op = &null_fops;
 707                         break;
 708 #if defined(CONFIG_ISA) || !defined(__mc68000__)
 709                 case 4:
 710                         filp->f_op = &port_fops;
 711                         break;
 712 #endif
 713                 case 5:
 714                         filp->f_op = &zero_fops;
 715                         break;
 716                 case 7:
 717                         filp->f_op = &full_fops;
 718                         break;
 719                 case 8:
 720                         filp->f_op = &random_fops;
 721                         break;
 722                 case 9:
 723                         filp->f_op = &urandom_fops;
 724                         break;
 725                 case 11:
 726                         filp->f_op = &kmsg_fops;
 727                         break;
 728                 default:
 729                         return -ENXIO;
 730         }
 731         if (filp->f_op && filp->f_op->open)
 732                 return filp->f_op->open(inode,filp);
 733         return 0;
 734 }
 735
 736 static struct file_operations memory_fops = {
 737         .open           = memory_open,  /* just a selector for the real open */
 738 };
 739
 740 static const struct {
 741         unsigned int            minor;
 742         char                    *name;
 743         umode_t                 mode;
 744         struct file_operations  *fops;
 745 } devlist[] = { /* list of minor devices */
 746         {1, "mem",     S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
 747         {2, "kmem",    S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops},
 748         {3, "null",    S_IRUGO | S_IWUGO,           &null_fops},
 749 #if defined(CONFIG_ISA) || !defined(__mc68000__)
 750         {4, "port",    S_IRUSR | S_IWUSR | S_IRGRP, &port_fops},
 751 #endif
 752         {5, "zero",    S_IRUGO | S_IWUGO,           &zero_fops},
 753         {7, "full",    S_IRUGO | S_IWUGO,           &full_fops},
 754         {8, "random",  S_IRUGO | S_IWUSR,           &random_fops},
 755         {9, "urandom", S_IRUGO | S_IWUSR,           &urandom_fops},
 756         {11,"kmsg",    S_IRUGO | S_IWUSR,           &kmsg_fops},
 757 };
 758
 759 static struct class_simple *mem_class;
 760
 761 static int __init chr_dev_init(void)
 762 {
 763         int i;
 764
 765         if (register_chrdev(MEM_MAJOR,"mem",&memory_fops))
 766                 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
 767
 768         mem_class = class_simple_create(THIS_MODULE, "mem");
 769         for (i = 0; i < ARRAY_SIZE(devlist); i++) {
 770                 class_simple_device_add(mem_class,
 771                                         MKDEV(MEM_MAJOR, devlist[i].minor),
 772                                         NULL, devlist[i].name);
 773                 devfs_mk_cdev(MKDEV(MEM_MAJOR, devlist[i].minor),
 774                                 S_IFCHR | devlist[i].mode, devlist[i].name);
 775         }
 776
 777 #if defined (CONFIG_FB)
 778         fbmem_init();
 779 #endif
 780         return 0;
 781 }
 782
 783 fs_initcall(chr_dev_init);