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