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 mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com> 9 */ 10 11#include <linux/mm.h> 12#include <linux/miscdevice.h> 13#include <linux/slab.h> 14#include <linux/vmalloc.h> 15#include <linux/mman.h> 16#include <linux/random.h> 17#include <linux/init.h> 18#include <linux/raw.h> 19#include <linux/tty.h> 20#include <linux/capability.h> 21#include <linux/ptrace.h> 22#include <linux/device.h> 23#include <linux/highmem.h> 24#include <linux/backing-dev.h> 25#include <linux/splice.h> 26#include <linux/pfn.h> 27#include <linux/export.h> 28#include <linux/io.h> 29#include <linux/uio.h> 30 31#include <linux/uaccess.h> 32 33#ifdef CONFIG_IA64 34# include <linux/efi.h> 35#endif 36 37#define DEVPORT_MINOR 4 38 39static inline unsigned long size_inside_page(unsigned long start, 40 unsigned long size) 41{ 42 unsigned long sz; 43 44 sz = PAGE_SIZE - (start & (PAGE_SIZE - 1)); 45 46 return min(sz, size); 47} 48 49#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE 50static inline int valid_phys_addr_range(phys_addr_t addr, size_t count) 51{ 52 return addr + count <= __pa(high_memory); 53} 54 55static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) 56{ 57 return 1; 58} 59#endif 60 61#ifdef CONFIG_STRICT_DEVMEM 62static inline int range_is_allowed(unsigned long pfn, unsigned long size) 63{ 64 u64 from = ((u64)pfn) << PAGE_SHIFT; 65 u64 to = from + size; 66 u64 cursor = from; 67 68 while (cursor < to) { 69 if (!devmem_is_allowed(pfn)) { 70 printk(KERN_INFO 71 "Program %s tried to access /dev/mem between %Lx->%Lx.\n", 72 current->comm, from, to); 73 return 0; 74 } 75 cursor += PAGE_SIZE; 76 pfn++; 77 } 78 return 1; 79} 80#else 81static inline int range_is_allowed(unsigned long pfn, unsigned long size) 82{ 83 return 1; 84} 85#endif 86 87#ifndef unxlate_dev_mem_ptr 88#define unxlate_dev_mem_ptr unxlate_dev_mem_ptr 89void __weak unxlate_dev_mem_ptr(phys_addr_t phys, void *addr) 90{ 91} 92#endif 93 94/* 95 * This funcion reads the *physical* memory. The f_pos points directly to the 96 * memory location. 97 */ 98static ssize_t read_mem(struct file *file, char __user *buf, 99 size_t count, loff_t *ppos) 100{ 101 phys_addr_t p = *ppos; 102 ssize_t read, sz; 103 void *ptr; 104 105 if (p != *ppos) 106 return 0; 107 108 if (!valid_phys_addr_range(p, count)) 109 return -EFAULT; 110 read = 0; 111#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 112 /* we don't have page 0 mapped on sparc and m68k.. */ 113 if (p < PAGE_SIZE) { 114 sz = size_inside_page(p, count); 115 if (sz > 0) { 116 if (clear_user(buf, sz)) 117 return -EFAULT; 118 buf += sz; 119 p += sz; 120 count -= sz; 121 read += sz; 122 } 123 } 124#endif 125 126 while (count > 0) { 127 unsigned long remaining; 128 129 sz = size_inside_page(p, count); 130 131 if (!range_is_allowed(p >> PAGE_SHIFT, count)) 132 return -EPERM; 133 134 /* 135 * On ia64 if a page has been mapped somewhere as uncached, then 136 * it must also be accessed uncached by the kernel or data 137 * corruption may occur. 138 */ 139 ptr = xlate_dev_mem_ptr(p); 140 if (!ptr) 141 return -EFAULT; 142 143 remaining = copy_to_user(buf, ptr, sz); 144 unxlate_dev_mem_ptr(p, ptr); 145 if (remaining) 146 return -EFAULT; 147 148 buf += sz; 149 p += sz; 150 count -= sz; 151 read += sz; 152 } 153 154 *ppos += read; 155 return read; 156} 157 158static ssize_t write_mem(struct file *file, const char __user *buf, 159 size_t count, loff_t *ppos) 160{ 161 phys_addr_t p = *ppos; 162 ssize_t written, sz; 163 unsigned long copied; 164 void *ptr; 165 166 if (p != *ppos) 167 return -EFBIG; 168 169 if (!valid_phys_addr_range(p, count)) 170 return -EFAULT; 171 172 written = 0; 173 174#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 175 /* we don't have page 0 mapped on sparc and m68k.. */ 176 if (p < PAGE_SIZE) { 177 sz = size_inside_page(p, count); 178 /* Hmm. Do something? */ 179 buf += sz; 180 p += sz; 181 count -= sz; 182 written += sz; 183 } 184#endif 185 186 while (count > 0) { 187 sz = size_inside_page(p, count); 188 189 if (!range_is_allowed(p >> PAGE_SHIFT, sz)) 190 return -EPERM; 191 192 /* 193 * On ia64 if a page has been mapped somewhere as uncached, then 194 * it must also be accessed uncached by the kernel or data 195 * corruption may occur. 196 */ 197 ptr = xlate_dev_mem_ptr(p); 198 if (!ptr) { 199 if (written) 200 break; 201 return -EFAULT; 202 } 203 204 copied = copy_from_user(ptr, buf, sz); 205 unxlate_dev_mem_ptr(p, ptr); 206 if (copied) { 207 written += sz - copied; 208 if (written) 209 break; 210 return -EFAULT; 211 } 212 213 buf += sz; 214 p += sz; 215 count -= sz; 216 written += sz; 217 } 218 219 *ppos += written; 220 return written; 221} 222 223int __weak phys_mem_access_prot_allowed(struct file *file, 224 unsigned long pfn, unsigned long size, pgprot_t *vma_prot) 225{ 226 return 1; 227} 228 229#ifndef __HAVE_PHYS_MEM_ACCESS_PROT 230 231/* 232 * Architectures vary in how they handle caching for addresses 233 * outside of main memory. 234 * 235 */ 236#ifdef pgprot_noncached 237static int uncached_access(struct file *file, phys_addr_t addr) 238{ 239#if defined(CONFIG_IA64) 240 /* 241 * On ia64, we ignore O_DSYNC because we cannot tolerate memory 242 * attribute aliases. 243 */ 244 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); 245#elif defined(CONFIG_MIPS) 246 { 247 extern int __uncached_access(struct file *file, 248 unsigned long addr); 249 250 return __uncached_access(file, addr); 251 } 252#else 253 /* 254 * Accessing memory above the top the kernel knows about or through a 255 * file pointer 256 * that was marked O_DSYNC will be done non-cached. 257 */ 258 if (file->f_flags & O_DSYNC) 259 return 1; 260 return addr >= __pa(high_memory); 261#endif 262} 263#endif 264 265static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 266 unsigned long size, pgprot_t vma_prot) 267{ 268#ifdef pgprot_noncached 269 phys_addr_t offset = pfn << PAGE_SHIFT; 270 271 if (uncached_access(file, offset)) 272 return pgprot_noncached(vma_prot); 273#endif 274 return vma_prot; 275} 276#endif 277 278#ifndef CONFIG_MMU 279static unsigned long get_unmapped_area_mem(struct file *file, 280 unsigned long addr, 281 unsigned long len, 282 unsigned long pgoff, 283 unsigned long flags) 284{ 285 if (!valid_mmap_phys_addr_range(pgoff, len)) 286 return (unsigned long) -EINVAL; 287 return pgoff << PAGE_SHIFT; 288} 289 290/* permit direct mmap, for read, write or exec */ 291static unsigned memory_mmap_capabilities(struct file *file) 292{ 293 return NOMMU_MAP_DIRECT | 294 NOMMU_MAP_READ | NOMMU_MAP_WRITE | NOMMU_MAP_EXEC; 295} 296 297static unsigned zero_mmap_capabilities(struct file *file) 298{ 299 return NOMMU_MAP_COPY; 300} 301 302/* can't do an in-place private mapping if there's no MMU */ 303static inline int private_mapping_ok(struct vm_area_struct *vma) 304{ 305 return vma->vm_flags & VM_MAYSHARE; 306} 307#else 308 309static inline int private_mapping_ok(struct vm_area_struct *vma) 310{ 311 return 1; 312} 313#endif 314 315static const struct vm_operations_struct mmap_mem_ops = { 316#ifdef CONFIG_HAVE_IOREMAP_PROT 317 .access = generic_access_phys 318#endif 319}; 320 321static int mmap_mem(struct file *file, struct vm_area_struct *vma) 322{ 323 size_t size = vma->vm_end - vma->vm_start; 324 325 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) 326 return -EINVAL; 327 328 if (!private_mapping_ok(vma)) 329 return -ENOSYS; 330 331 if (!range_is_allowed(vma->vm_pgoff, size)) 332 return -EPERM; 333 334 if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, 335 &vma->vm_page_prot)) 336 return -EINVAL; 337 338 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, 339 size, 340 vma->vm_page_prot); 341 342 vma->vm_ops = &mmap_mem_ops; 343 344 /* Remap-pfn-range will mark the range VM_IO */ 345 if (remap_pfn_range(vma, 346 vma->vm_start, 347 vma->vm_pgoff, 348 size, 349 vma->vm_page_prot)) { 350 return -EAGAIN; 351 } 352 return 0; 353} 354 355static int mmap_kmem(struct file *file, struct vm_area_struct *vma) 356{ 357 unsigned long pfn; 358 359 /* Turn a kernel-virtual address into a physical page frame */ 360 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; 361 362 /* 363 * RED-PEN: on some architectures there is more mapped memory than 364 * available in mem_map which pfn_valid checks for. Perhaps should add a 365 * new macro here. 366 * 367 * RED-PEN: vmalloc is not supported right now. 368 */ 369 if (!pfn_valid(pfn)) 370 return -EIO; 371 372 vma->vm_pgoff = pfn; 373 return mmap_mem(file, vma); 374} 375 376/* 377 * This function reads the *virtual* memory as seen by the kernel. 378 */ 379static ssize_t read_kmem(struct file *file, char __user *buf, 380 size_t count, loff_t *ppos) 381{ 382 unsigned long p = *ppos; 383 ssize_t low_count, read, sz; 384 char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ 385 int err = 0; 386 387 read = 0; 388 if (p < (unsigned long) high_memory) { 389 low_count = count; 390 if (count > (unsigned long)high_memory - p) 391 low_count = (unsigned long)high_memory - p; 392 393#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 394 /* we don't have page 0 mapped on sparc and m68k.. */ 395 if (p < PAGE_SIZE && low_count > 0) { 396 sz = size_inside_page(p, low_count); 397 if (clear_user(buf, sz)) 398 return -EFAULT; 399 buf += sz; 400 p += sz; 401 read += sz; 402 low_count -= sz; 403 count -= sz; 404 } 405#endif 406 while (low_count > 0) { 407 sz = size_inside_page(p, low_count); 408 409 /* 410 * On ia64 if a page has been mapped somewhere as 411 * uncached, then it must also be accessed uncached 412 * by the kernel or data corruption may occur 413 */ 414 kbuf = xlate_dev_kmem_ptr((void *)p); 415 416 if (copy_to_user(buf, kbuf, sz)) 417 return -EFAULT; 418 buf += sz; 419 p += sz; 420 read += sz; 421 low_count -= sz; 422 count -= sz; 423 } 424 } 425 426 if (count > 0) { 427 kbuf = (char *)__get_free_page(GFP_KERNEL); 428 if (!kbuf) 429 return -ENOMEM; 430 while (count > 0) { 431 sz = size_inside_page(p, count); 432 if (!is_vmalloc_or_module_addr((void *)p)) { 433 err = -ENXIO; 434 break; 435 } 436 sz = vread(kbuf, (char *)p, sz); 437 if (!sz) 438 break; 439 if (copy_to_user(buf, kbuf, sz)) { 440 err = -EFAULT; 441 break; 442 } 443 count -= sz; 444 buf += sz; 445 read += sz; 446 p += sz; 447 } 448 free_page((unsigned long)kbuf); 449 } 450 *ppos = p; 451 return read ? read : err; 452} 453 454 455static ssize_t do_write_kmem(unsigned long p, const char __user *buf, 456 size_t count, loff_t *ppos) 457{ 458 ssize_t written, sz; 459 unsigned long copied; 460 461 written = 0; 462#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 463 /* we don't have page 0 mapped on sparc and m68k.. */ 464 if (p < PAGE_SIZE) { 465 sz = size_inside_page(p, count); 466 /* Hmm. Do something? */ 467 buf += sz; 468 p += sz; 469 count -= sz; 470 written += sz; 471 } 472#endif 473 474 while (count > 0) { 475 void *ptr; 476 477 sz = size_inside_page(p, count); 478 479 /* 480 * On ia64 if a page has been mapped somewhere as uncached, then 481 * it must also be accessed uncached by the kernel or data 482 * corruption may occur. 483 */ 484 ptr = xlate_dev_kmem_ptr((void *)p); 485 486 copied = copy_from_user(ptr, buf, sz); 487 if (copied) { 488 written += sz - copied; 489 if (written) 490 break; 491 return -EFAULT; 492 } 493 buf += sz; 494 p += sz; 495 count -= sz; 496 written += sz; 497 } 498 499 *ppos += written; 500 return written; 501} 502 503/* 504 * This function writes to the *virtual* memory as seen by the kernel. 505 */ 506static ssize_t write_kmem(struct file *file, const char __user *buf, 507 size_t count, loff_t *ppos) 508{ 509 unsigned long p = *ppos; 510 ssize_t wrote = 0; 511 ssize_t virtr = 0; 512 char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ 513 int err = 0; 514 515 if (p < (unsigned long) high_memory) { 516 unsigned long to_write = min_t(unsigned long, count, 517 (unsigned long)high_memory - p); 518 wrote = do_write_kmem(p, buf, to_write, ppos); 519 if (wrote != to_write) 520 return wrote; 521 p += wrote; 522 buf += wrote; 523 count -= wrote; 524 } 525 526 if (count > 0) { 527 kbuf = (char *)__get_free_page(GFP_KERNEL); 528 if (!kbuf) 529 return wrote ? wrote : -ENOMEM; 530 while (count > 0) { 531 unsigned long sz = size_inside_page(p, count); 532 unsigned long n; 533 534 if (!is_vmalloc_or_module_addr((void *)p)) { 535 err = -ENXIO; 536 break; 537 } 538 n = copy_from_user(kbuf, buf, sz); 539 if (n) { 540 err = -EFAULT; 541 break; 542 } 543 vwrite(kbuf, (char *)p, sz); 544 count -= sz; 545 buf += sz; 546 virtr += sz; 547 p += sz; 548 } 549 free_page((unsigned long)kbuf); 550 } 551 552 *ppos = p; 553 return virtr + wrote ? : err; 554} 555 556static ssize_t read_port(struct file *file, char __user *buf, 557 size_t count, loff_t *ppos) 558{ 559 unsigned long i = *ppos; 560 char __user *tmp = buf; 561 562 if (!access_ok(VERIFY_WRITE, buf, count)) 563 return -EFAULT; 564 while (count-- > 0 && i < 65536) { 565 if (__put_user(inb(i), tmp) < 0) 566 return -EFAULT; 567 i++; 568 tmp++; 569 } 570 *ppos = i; 571 return tmp-buf; 572} 573 574static ssize_t write_port(struct file *file, const char __user *buf, 575 size_t count, loff_t *ppos) 576{ 577 unsigned long i = *ppos; 578 const char __user *tmp = buf; 579 580 if (!access_ok(VERIFY_READ, buf, count)) 581 return -EFAULT; 582 while (count-- > 0 && i < 65536) { 583 char c; 584 585 if (__get_user(c, tmp)) { 586 if (tmp > buf) 587 break; 588 return -EFAULT; 589 } 590 outb(c, i); 591 i++; 592 tmp++; 593 } 594 *ppos = i; 595 return tmp-buf; 596} 597 598static ssize_t read_null(struct file *file, char __user *buf, 599 size_t count, loff_t *ppos) 600{ 601 return 0; 602} 603 604static ssize_t write_null(struct file *file, const char __user *buf, 605 size_t count, loff_t *ppos) 606{ 607 return count; 608} 609 610static ssize_t read_iter_null(struct kiocb *iocb, struct iov_iter *to) 611{ 612 return 0; 613} 614 615static ssize_t write_iter_null(struct kiocb *iocb, struct iov_iter *from) 616{ 617 size_t count = iov_iter_count(from); 618 iov_iter_advance(from, count); 619 return count; 620} 621 622static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, 623 struct splice_desc *sd) 624{ 625 return sd->len; 626} 627 628static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out, 629 loff_t *ppos, size_t len, unsigned int flags) 630{ 631 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); 632} 633 634static ssize_t read_iter_zero(struct kiocb *iocb, struct iov_iter *iter) 635{ 636 size_t written = 0; 637 638 while (iov_iter_count(iter)) { 639 size_t chunk = iov_iter_count(iter), n; 640 641 if (chunk > PAGE_SIZE) 642 chunk = PAGE_SIZE; /* Just for latency reasons */ 643 n = iov_iter_zero(chunk, iter); 644 if (!n && iov_iter_count(iter)) 645 return written ? written : -EFAULT; 646 written += n; 647 if (signal_pending(current)) 648 return written ? written : -ERESTARTSYS; 649 cond_resched(); 650 } 651 return written; 652} 653 654static int mmap_zero(struct file *file, struct vm_area_struct *vma) 655{ 656#ifndef CONFIG_MMU 657 return -ENOSYS; 658#endif 659 if (vma->vm_flags & VM_SHARED) 660 return shmem_zero_setup(vma); 661 return 0; 662} 663 664static ssize_t write_full(struct file *file, const char __user *buf, 665 size_t count, loff_t *ppos) 666{ 667 return -ENOSPC; 668} 669 670/* 671 * Special lseek() function for /dev/null and /dev/zero. Most notably, you 672 * can fopen() both devices with "a" now. This was previously impossible. 673 * -- SRB. 674 */ 675static loff_t null_lseek(struct file *file, loff_t offset, int orig) 676{ 677 return file->f_pos = 0; 678} 679 680/* 681 * The memory devices use the full 32/64 bits of the offset, and so we cannot 682 * check against negative addresses: they are ok. The return value is weird, 683 * though, in that case (0). 684 * 685 * also note that seeking relative to the "end of file" isn't supported: 686 * it has no meaning, so it returns -EINVAL. 687 */ 688static loff_t memory_lseek(struct file *file, loff_t offset, int orig) 689{ 690 loff_t ret; 691 692 mutex_lock(&file_inode(file)->i_mutex); 693 switch (orig) { 694 case SEEK_CUR: 695 offset += file->f_pos; 696 case SEEK_SET: 697 /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */ 698 if (IS_ERR_VALUE((unsigned long long)offset)) { 699 ret = -EOVERFLOW; 700 break; 701 } 702 file->f_pos = offset; 703 ret = file->f_pos; 704 force_successful_syscall_return(); 705 break; 706 default: 707 ret = -EINVAL; 708 } 709 mutex_unlock(&file_inode(file)->i_mutex); 710 return ret; 711} 712 713static int open_port(struct inode *inode, struct file *filp) 714{ 715 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; 716} 717 718#define zero_lseek null_lseek 719#define full_lseek null_lseek 720#define write_zero write_null 721#define write_iter_zero write_iter_null 722#define open_mem open_port 723#define open_kmem open_mem 724 725static const struct file_operations __maybe_unused mem_fops = { 726 .llseek = memory_lseek, 727 .read = read_mem, 728 .write = write_mem, 729 .mmap = mmap_mem, 730 .open = open_mem, 731#ifndef CONFIG_MMU 732 .get_unmapped_area = get_unmapped_area_mem, 733 .mmap_capabilities = memory_mmap_capabilities, 734#endif 735}; 736 737static const struct file_operations __maybe_unused kmem_fops = { 738 .llseek = memory_lseek, 739 .read = read_kmem, 740 .write = write_kmem, 741 .mmap = mmap_kmem, 742 .open = open_kmem, 743#ifndef CONFIG_MMU 744 .get_unmapped_area = get_unmapped_area_mem, 745 .mmap_capabilities = memory_mmap_capabilities, 746#endif 747}; 748 749static const struct file_operations null_fops = { 750 .llseek = null_lseek, 751 .read = read_null, 752 .write = write_null, 753 .read_iter = read_iter_null, 754 .write_iter = write_iter_null, 755 .splice_write = splice_write_null, 756}; 757 758static const struct file_operations __maybe_unused port_fops = { 759 .llseek = memory_lseek, 760 .read = read_port, 761 .write = write_port, 762 .open = open_port, 763}; 764 765static const struct file_operations zero_fops = { 766 .llseek = zero_lseek, 767 .write = write_zero, 768 .read_iter = read_iter_zero, 769 .write_iter = write_iter_zero, 770 .mmap = mmap_zero, 771#ifndef CONFIG_MMU 772 .mmap_capabilities = zero_mmap_capabilities, 773#endif 774}; 775 776static const struct file_operations full_fops = { 777 .llseek = full_lseek, 778 .read_iter = read_iter_zero, 779 .write = write_full, 780}; 781 782static const struct memdev { 783 const char *name; 784 umode_t mode; 785 const struct file_operations *fops; 786 fmode_t fmode; 787} devlist[] = { 788#ifdef CONFIG_DEVMEM 789 [1] = { "mem", 0, &mem_fops, FMODE_UNSIGNED_OFFSET }, 790#endif 791#ifdef CONFIG_DEVKMEM 792 [2] = { "kmem", 0, &kmem_fops, FMODE_UNSIGNED_OFFSET }, 793#endif 794 [3] = { "null", 0666, &null_fops, 0 }, 795#ifdef CONFIG_DEVPORT 796 [4] = { "port", 0, &port_fops, 0 }, 797#endif 798 [5] = { "zero", 0666, &zero_fops, 0 }, 799 [7] = { "full", 0666, &full_fops, 0 }, 800 [8] = { "random", 0666, &random_fops, 0 }, 801 [9] = { "urandom", 0666, &urandom_fops, 0 }, 802#ifdef CONFIG_PRINTK 803 [11] = { "kmsg", 0644, &kmsg_fops, 0 }, 804#endif 805}; 806 807static int memory_open(struct inode *inode, struct file *filp) 808{ 809 int minor; 810 const struct memdev *dev; 811 812 minor = iminor(inode); 813 if (minor >= ARRAY_SIZE(devlist)) 814 return -ENXIO; 815 816 dev = &devlist[minor]; 817 if (!dev->fops) 818 return -ENXIO; 819 820 filp->f_op = dev->fops; 821 filp->f_mode |= dev->fmode; 822 823 if (dev->fops->open) 824 return dev->fops->open(inode, filp); 825 826 return 0; 827} 828 829static const struct file_operations memory_fops = { 830 .open = memory_open, 831 .llseek = noop_llseek, 832}; 833 834static char *mem_devnode(struct device *dev, umode_t *mode) 835{ 836 if (mode && devlist[MINOR(dev->devt)].mode) 837 *mode = devlist[MINOR(dev->devt)].mode; 838 return NULL; 839} 840 841static struct class *mem_class; 842 843static int __init chr_dev_init(void) 844{ 845 int minor; 846 847 if (register_chrdev(MEM_MAJOR, "mem", &memory_fops)) 848 printk("unable to get major %d for memory devs\n", MEM_MAJOR); 849 850 mem_class = class_create(THIS_MODULE, "mem"); 851 if (IS_ERR(mem_class)) 852 return PTR_ERR(mem_class); 853 854 mem_class->devnode = mem_devnode; 855 for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) { 856 if (!devlist[minor].name) 857 continue; 858 859 /* 860 * Create /dev/port? 861 */ 862 if ((minor == DEVPORT_MINOR) && !arch_has_dev_port()) 863 continue; 864 865 device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor), 866 NULL, devlist[minor].name); 867 } 868 869 return tty_init(); 870} 871 872fs_initcall(chr_dev_init); 873