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