1 /* 2 * linux/drivers/char/mem.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 * 6 * Added devfs support. 7 * Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu> 8 * Shared /dev/zero mmaping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com> 9 */ 10 11 #include <linux/config.h> 12 #include <linux/mm.h> 13 #include <linux/miscdevice.h> 14 #include <linux/slab.h> 15 #include <linux/vmalloc.h> 16 #include <linux/mman.h> 17 #include <linux/random.h> 18 #include <linux/init.h> 19 #include <linux/raw.h> 20 #include <linux/tty.h> 21 #include <linux/capability.h> 22 #include <linux/smp_lock.h> 23 #include <linux/devfs_fs_kernel.h> 24 #include <linux/ptrace.h> 25 #include <linux/device.h> 26 #include <linux/highmem.h> 27 #include <linux/crash_dump.h> 28 #include <linux/backing-dev.h> 29 #include <linux/bootmem.h> 30 31 #include <asm/uaccess.h> 32 #include <asm/io.h> 33 34 #ifdef CONFIG_IA64 35 # include <linux/efi.h> 36 #endif 37 38 /* 39 * Architectures vary in how they handle caching for addresses 40 * outside of main memory. 41 * 42 */ 43 static inline int uncached_access(struct file *file, unsigned long addr) 44 { 45 #if defined(__i386__) 46 /* 47 * On the PPro and successors, the MTRRs are used to set 48 * memory types for physical addresses outside main memory, 49 * so blindly setting PCD or PWT on those pages is wrong. 50 * For Pentiums and earlier, the surround logic should disable 51 * caching for the high addresses through the KEN pin, but 52 * we maintain the tradition of paranoia in this code. 53 */ 54 if (file->f_flags & O_SYNC) 55 return 1; 56 return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) || 57 test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) || 58 test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) || 59 test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) ) 60 && addr >= __pa(high_memory); 61 #elif defined(__x86_64__) 62 /* 63 * This is broken because it can generate memory type aliases, 64 * which can cause cache corruptions 65 * But it is only available for root and we have to be bug-to-bug 66 * compatible with i386. 67 */ 68 if (file->f_flags & O_SYNC) 69 return 1; 70 /* same behaviour as i386. PAT always set to cached and MTRRs control the 71 caching behaviour. 72 Hopefully a full PAT implementation will fix that soon. */ 73 return 0; 74 #elif defined(CONFIG_IA64) 75 /* 76 * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases. 77 */ 78 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); 79 #else 80 /* 81 * Accessing memory above the top the kernel knows about or through a file pointer 82 * that was marked O_SYNC will be done non-cached. 83 */ 84 if (file->f_flags & O_SYNC) 85 return 1; 86 return addr >= __pa(high_memory); 87 #endif 88 } 89 90 #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE 91 static inline int valid_phys_addr_range(unsigned long addr, size_t *count) 92 { 93 unsigned long end_mem; 94 95 end_mem = __pa(high_memory); 96 if (addr >= end_mem) 97 return 0; 98 99 if (*count > end_mem - addr) 100 *count = end_mem - addr; 101 102 return 1; 103 } 104 #endif 105 106 /* 107 * This funcion reads the *physical* memory. The f_pos points directly to the 108 * memory location. 109 */ 110 static ssize_t read_mem(struct file * file, char __user * buf, 111 size_t count, loff_t *ppos) 112 { 113 unsigned long p = *ppos; 114 ssize_t read, sz; 115 char *ptr; 116 117 if (!valid_phys_addr_range(p, &count)) 118 return -EFAULT; 119 read = 0; 120 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 121 /* we don't have page 0 mapped on sparc and m68k.. */ 122 if (p < PAGE_SIZE) { 123 sz = PAGE_SIZE - p; 124 if (sz > count) 125 sz = count; 126 if (sz > 0) { 127 if (clear_user(buf, sz)) 128 return -EFAULT; 129 buf += sz; 130 p += sz; 131 count -= sz; 132 read += sz; 133 } 134 } 135 #endif 136 137 while (count > 0) { 138 /* 139 * Handle first page in case it's not aligned 140 */ 141 if (-p & (PAGE_SIZE - 1)) 142 sz = -p & (PAGE_SIZE - 1); 143 else 144 sz = PAGE_SIZE; 145 146 sz = min_t(unsigned long, sz, count); 147 148 /* 149 * On ia64 if a page has been mapped somewhere as 150 * uncached, then it must also be accessed uncached 151 * by the kernel or data corruption may occur 152 */ 153 ptr = xlate_dev_mem_ptr(p); 154 155 if (copy_to_user(buf, ptr, sz)) 156 return -EFAULT; 157 buf += sz; 158 p += sz; 159 count -= sz; 160 read += sz; 161 } 162 163 *ppos += read; 164 return read; 165 } 166 167 static ssize_t write_mem(struct file * file, const char __user * buf, 168 size_t count, loff_t *ppos) 169 { 170 unsigned long p = *ppos; 171 ssize_t written, sz; 172 unsigned long copied; 173 void *ptr; 174 175 if (!valid_phys_addr_range(p, &count)) 176 return -EFAULT; 177 178 written = 0; 179 180 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 181 /* we don't have page 0 mapped on sparc and m68k.. */ 182 if (p < PAGE_SIZE) { 183 unsigned long sz = PAGE_SIZE - p; 184 if (sz > count) 185 sz = count; 186 /* Hmm. Do something? */ 187 buf += sz; 188 p += sz; 189 count -= sz; 190 written += sz; 191 } 192 #endif 193 194 while (count > 0) { 195 /* 196 * Handle first page in case it's not aligned 197 */ 198 if (-p & (PAGE_SIZE - 1)) 199 sz = -p & (PAGE_SIZE - 1); 200 else 201 sz = PAGE_SIZE; 202 203 sz = min_t(unsigned long, sz, count); 204 205 /* 206 * On ia64 if a page has been mapped somewhere as 207 * uncached, then it must also be accessed uncached 208 * by the kernel or data corruption may occur 209 */ 210 ptr = xlate_dev_mem_ptr(p); 211 212 copied = copy_from_user(ptr, buf, sz); 213 if (copied) { 214 ssize_t ret; 215 216 ret = written + (sz - copied); 217 if (ret) 218 return ret; 219 return -EFAULT; 220 } 221 buf += sz; 222 p += sz; 223 count -= sz; 224 written += sz; 225 } 226 227 *ppos += written; 228 return written; 229 } 230 231 static int mmap_mem(struct file * file, struct vm_area_struct * vma) 232 { 233 #if defined(__HAVE_PHYS_MEM_ACCESS_PROT) 234 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, 235 vma->vm_end - vma->vm_start, 236 vma->vm_page_prot); 237 #elif defined(pgprot_noncached) 238 unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; 239 int uncached; 240 241 uncached = uncached_access(file, offset); 242 if (uncached) 243 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 244 #endif 245 246 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ 247 if (remap_pfn_range(vma, 248 vma->vm_start, 249 vma->vm_pgoff, 250 vma->vm_end-vma->vm_start, 251 vma->vm_page_prot)) 252 return -EAGAIN; 253 return 0; 254 } 255 256 static int mmap_kmem(struct file * file, struct vm_area_struct * vma) 257 { 258 unsigned long pfn; 259 260 /* Turn a kernel-virtual address into a physical page frame */ 261 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; 262 263 /* 264 * RED-PEN: on some architectures there is more mapped memory 265 * than available in mem_map which pfn_valid checks 266 * for. Perhaps should add a new macro here. 267 * 268 * RED-PEN: vmalloc is not supported right now. 269 */ 270 if (!pfn_valid(pfn)) 271 return -EIO; 272 273 vma->vm_pgoff = pfn; 274 return mmap_mem(file, vma); 275 } 276 277 #ifdef CONFIG_CRASH_DUMP 278 /* 279 * Read memory corresponding to the old kernel. 280 */ 281 static ssize_t read_oldmem(struct file *file, char __user *buf, 282 size_t count, loff_t *ppos) 283 { 284 unsigned long pfn, offset; 285 size_t read = 0, csize; 286 int rc = 0; 287 288 while (count) { 289 pfn = *ppos / PAGE_SIZE; 290 if (pfn > saved_max_pfn) 291 return read; 292 293 offset = (unsigned long)(*ppos % PAGE_SIZE); 294 if (count > PAGE_SIZE - offset) 295 csize = PAGE_SIZE - offset; 296 else 297 csize = count; 298 299 rc = copy_oldmem_page(pfn, buf, csize, offset, 1); 300 if (rc < 0) 301 return rc; 302 buf += csize; 303 *ppos += csize; 304 read += csize; 305 count -= csize; 306 } 307 return read; 308 } 309 #endif 310 311 extern long vread(char *buf, char *addr, unsigned long count); 312 extern long vwrite(char *buf, char *addr, unsigned long count); 313 314 /* 315 * This function reads the *virtual* memory as seen by the kernel. 316 */ 317 static ssize_t read_kmem(struct file *file, char __user *buf, 318 size_t count, loff_t *ppos) 319 { 320 unsigned long p = *ppos; 321 ssize_t low_count, read, sz; 322 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ 323 324 read = 0; 325 if (p < (unsigned long) high_memory) { 326 low_count = count; 327 if (count > (unsigned long) high_memory - p) 328 low_count = (unsigned long) high_memory - p; 329 330 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 331 /* we don't have page 0 mapped on sparc and m68k.. */ 332 if (p < PAGE_SIZE && low_count > 0) { 333 size_t tmp = PAGE_SIZE - p; 334 if (tmp > low_count) tmp = low_count; 335 if (clear_user(buf, tmp)) 336 return -EFAULT; 337 buf += tmp; 338 p += tmp; 339 read += tmp; 340 low_count -= tmp; 341 count -= tmp; 342 } 343 #endif 344 while (low_count > 0) { 345 /* 346 * Handle first page in case it's not aligned 347 */ 348 if (-p & (PAGE_SIZE - 1)) 349 sz = -p & (PAGE_SIZE - 1); 350 else 351 sz = PAGE_SIZE; 352 353 sz = min_t(unsigned long, sz, low_count); 354 355 /* 356 * On ia64 if a page has been mapped somewhere as 357 * uncached, then it must also be accessed uncached 358 * by the kernel or data corruption may occur 359 */ 360 kbuf = xlate_dev_kmem_ptr((char *)p); 361 362 if (copy_to_user(buf, kbuf, sz)) 363 return -EFAULT; 364 buf += sz; 365 p += sz; 366 read += sz; 367 low_count -= sz; 368 count -= sz; 369 } 370 } 371 372 if (count > 0) { 373 kbuf = (char *)__get_free_page(GFP_KERNEL); 374 if (!kbuf) 375 return -ENOMEM; 376 while (count > 0) { 377 int len = count; 378 379 if (len > PAGE_SIZE) 380 len = PAGE_SIZE; 381 len = vread(kbuf, (char *)p, len); 382 if (!len) 383 break; 384 if (copy_to_user(buf, kbuf, len)) { 385 free_page((unsigned long)kbuf); 386 return -EFAULT; 387 } 388 count -= len; 389 buf += len; 390 read += len; 391 p += len; 392 } 393 free_page((unsigned long)kbuf); 394 } 395 *ppos = p; 396 return read; 397 } 398 399 400 static inline ssize_t 401 do_write_kmem(void *p, unsigned long realp, const char __user * buf, 402 size_t count, loff_t *ppos) 403 { 404 ssize_t written, sz; 405 unsigned long copied; 406 407 written = 0; 408 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 409 /* we don't have page 0 mapped on sparc and m68k.. */ 410 if (realp < PAGE_SIZE) { 411 unsigned long sz = PAGE_SIZE - realp; 412 if (sz > count) 413 sz = count; 414 /* Hmm. Do something? */ 415 buf += sz; 416 p += sz; 417 realp += sz; 418 count -= sz; 419 written += sz; 420 } 421 #endif 422 423 while (count > 0) { 424 char *ptr; 425 /* 426 * Handle first page in case it's not aligned 427 */ 428 if (-realp & (PAGE_SIZE - 1)) 429 sz = -realp & (PAGE_SIZE - 1); 430 else 431 sz = PAGE_SIZE; 432 433 sz = min_t(unsigned long, sz, count); 434 435 /* 436 * On ia64 if a page has been mapped somewhere as 437 * uncached, then it must also be accessed uncached 438 * by the kernel or data corruption may occur 439 */ 440 ptr = xlate_dev_kmem_ptr(p); 441 442 copied = copy_from_user(ptr, buf, sz); 443 if (copied) { 444 ssize_t ret; 445 446 ret = written + (sz - copied); 447 if (ret) 448 return ret; 449 return -EFAULT; 450 } 451 buf += sz; 452 p += sz; 453 realp += sz; 454 count -= sz; 455 written += sz; 456 } 457 458 *ppos += written; 459 return written; 460 } 461 462 463 /* 464 * This function writes to the *virtual* memory as seen by the kernel. 465 */ 466 static ssize_t write_kmem(struct file * file, const char __user * buf, 467 size_t count, loff_t *ppos) 468 { 469 unsigned long p = *ppos; 470 ssize_t wrote = 0; 471 ssize_t virtr = 0; 472 ssize_t written; 473 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ 474 475 if (p < (unsigned long) high_memory) { 476 477 wrote = count; 478 if (count > (unsigned long) high_memory - p) 479 wrote = (unsigned long) high_memory - p; 480 481 written = do_write_kmem((void*)p, p, buf, wrote, ppos); 482 if (written != wrote) 483 return written; 484 wrote = written; 485 p += wrote; 486 buf += wrote; 487 count -= wrote; 488 } 489 490 if (count > 0) { 491 kbuf = (char *)__get_free_page(GFP_KERNEL); 492 if (!kbuf) 493 return wrote ? wrote : -ENOMEM; 494 while (count > 0) { 495 int len = count; 496 497 if (len > PAGE_SIZE) 498 len = PAGE_SIZE; 499 if (len) { 500 written = copy_from_user(kbuf, buf, len); 501 if (written) { 502 ssize_t ret; 503 504 free_page((unsigned long)kbuf); 505 ret = wrote + virtr + (len - written); 506 return ret ? ret : -EFAULT; 507 } 508 } 509 len = vwrite(kbuf, (char *)p, len); 510 count -= len; 511 buf += len; 512 virtr += len; 513 p += len; 514 } 515 free_page((unsigned long)kbuf); 516 } 517 518 *ppos = p; 519 return virtr + wrote; 520 } 521 522 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI)) 523 static ssize_t read_port(struct file * file, char __user * buf, 524 size_t count, loff_t *ppos) 525 { 526 unsigned long i = *ppos; 527 char __user *tmp = buf; 528 529 if (!access_ok(VERIFY_WRITE, buf, count)) 530 return -EFAULT; 531 while (count-- > 0 && i < 65536) { 532 if (__put_user(inb(i),tmp) < 0) 533 return -EFAULT; 534 i++; 535 tmp++; 536 } 537 *ppos = i; 538 return tmp-buf; 539 } 540 541 static ssize_t write_port(struct file * file, const char __user * buf, 542 size_t count, loff_t *ppos) 543 { 544 unsigned long i = *ppos; 545 const char __user * tmp = buf; 546 547 if (!access_ok(VERIFY_READ,buf,count)) 548 return -EFAULT; 549 while (count-- > 0 && i < 65536) { 550 char c; 551 if (__get_user(c, tmp)) 552 return -EFAULT; 553 outb(c,i); 554 i++; 555 tmp++; 556 } 557 *ppos = i; 558 return tmp-buf; 559 } 560 #endif 561 562 static ssize_t read_null(struct file * file, char __user * buf, 563 size_t count, loff_t *ppos) 564 { 565 return 0; 566 } 567 568 static ssize_t write_null(struct file * file, const char __user * buf, 569 size_t count, loff_t *ppos) 570 { 571 return count; 572 } 573 574 #ifdef CONFIG_MMU 575 /* 576 * For fun, we are using the MMU for this. 577 */ 578 static inline size_t read_zero_pagealigned(char __user * buf, size_t size) 579 { 580 struct mm_struct *mm; 581 struct vm_area_struct * vma; 582 unsigned long addr=(unsigned long)buf; 583 584 mm = current->mm; 585 /* Oops, this was forgotten before. -ben */ 586 down_read(&mm->mmap_sem); 587 588 /* For private mappings, just map in zero pages. */ 589 for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) { 590 unsigned long count; 591 592 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0) 593 goto out_up; 594 if (vma->vm_flags & (VM_SHARED | VM_HUGETLB)) 595 break; 596 count = vma->vm_end - addr; 597 if (count > size) 598 count = size; 599 600 zap_page_range(vma, addr, count, NULL); 601 zeromap_page_range(vma, addr, count, PAGE_COPY); 602 603 size -= count; 604 buf += count; 605 addr += count; 606 if (size == 0) 607 goto out_up; 608 } 609 610 up_read(&mm->mmap_sem); 611 612 /* The shared case is hard. Let's do the conventional zeroing. */ 613 do { 614 unsigned long unwritten = clear_user(buf, PAGE_SIZE); 615 if (unwritten) 616 return size + unwritten - PAGE_SIZE; 617 cond_resched(); 618 buf += PAGE_SIZE; 619 size -= PAGE_SIZE; 620 } while (size); 621 622 return size; 623 out_up: 624 up_read(&mm->mmap_sem); 625 return size; 626 } 627 628 static ssize_t read_zero(struct file * file, char __user * buf, 629 size_t count, loff_t *ppos) 630 { 631 unsigned long left, unwritten, written = 0; 632 633 if (!count) 634 return 0; 635 636 if (!access_ok(VERIFY_WRITE, buf, count)) 637 return -EFAULT; 638 639 left = count; 640 641 /* do we want to be clever? Arbitrary cut-off */ 642 if (count >= PAGE_SIZE*4) { 643 unsigned long partial; 644 645 /* How much left of the page? */ 646 partial = (PAGE_SIZE-1) & -(unsigned long) buf; 647 unwritten = clear_user(buf, partial); 648 written = partial - unwritten; 649 if (unwritten) 650 goto out; 651 left -= partial; 652 buf += partial; 653 unwritten = read_zero_pagealigned(buf, left & PAGE_MASK); 654 written += (left & PAGE_MASK) - unwritten; 655 if (unwritten) 656 goto out; 657 buf += left & PAGE_MASK; 658 left &= ~PAGE_MASK; 659 } 660 unwritten = clear_user(buf, left); 661 written += left - unwritten; 662 out: 663 return written ? written : -EFAULT; 664 } 665 666 static int mmap_zero(struct file * file, struct vm_area_struct * vma) 667 { 668 if (vma->vm_flags & VM_SHARED) 669 return shmem_zero_setup(vma); 670 if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot)) 671 return -EAGAIN; 672 return 0; 673 } 674 #else /* CONFIG_MMU */ 675 static ssize_t read_zero(struct file * file, char * buf, 676 size_t count, loff_t *ppos) 677 { 678 size_t todo = count; 679 680 while (todo) { 681 size_t chunk = todo; 682 683 if (chunk > 4096) 684 chunk = 4096; /* Just for latency reasons */ 685 if (clear_user(buf, chunk)) 686 return -EFAULT; 687 buf += chunk; 688 todo -= chunk; 689 cond_resched(); 690 } 691 return count; 692 } 693 694 static int mmap_zero(struct file * file, struct vm_area_struct * vma) 695 { 696 return -ENOSYS; 697 } 698 #endif /* CONFIG_MMU */ 699 700 static ssize_t write_full(struct file * file, const char __user * buf, 701 size_t count, loff_t *ppos) 702 { 703 return -ENOSPC; 704 } 705 706 /* 707 * Special lseek() function for /dev/null and /dev/zero. Most notably, you 708 * can fopen() both devices with "a" now. This was previously impossible. 709 * -- SRB. 710 */ 711 712 static loff_t null_lseek(struct file * file, loff_t offset, int orig) 713 { 714 return file->f_pos = 0; 715 } 716 717 /* 718 * The memory devices use the full 32/64 bits of the offset, and so we cannot 719 * check against negative addresses: they are ok. The return value is weird, 720 * though, in that case (0). 721 * 722 * also note that seeking relative to the "end of file" isn't supported: 723 * it has no meaning, so it returns -EINVAL. 724 */ 725 static loff_t memory_lseek(struct file * file, loff_t offset, int orig) 726 { 727 loff_t ret; 728 729 down(&file->f_dentry->d_inode->i_sem); 730 switch (orig) { 731 case 0: 732 file->f_pos = offset; 733 ret = file->f_pos; 734 force_successful_syscall_return(); 735 break; 736 case 1: 737 file->f_pos += offset; 738 ret = file->f_pos; 739 force_successful_syscall_return(); 740 break; 741 default: 742 ret = -EINVAL; 743 } 744 up(&file->f_dentry->d_inode->i_sem); 745 return ret; 746 } 747 748 static int open_port(struct inode * inode, struct file * filp) 749 { 750 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; 751 } 752 753 #define zero_lseek null_lseek 754 #define full_lseek null_lseek 755 #define write_zero write_null 756 #define read_full read_zero 757 #define open_mem open_port 758 #define open_kmem open_mem 759 #define open_oldmem open_mem 760 761 static struct file_operations mem_fops = { 762 .llseek = memory_lseek, 763 .read = read_mem, 764 .write = write_mem, 765 .mmap = mmap_mem, 766 .open = open_mem, 767 }; 768 769 static struct file_operations kmem_fops = { 770 .llseek = memory_lseek, 771 .read = read_kmem, 772 .write = write_kmem, 773 .mmap = mmap_kmem, 774 .open = open_kmem, 775 }; 776 777 static struct file_operations null_fops = { 778 .llseek = null_lseek, 779 .read = read_null, 780 .write = write_null, 781 }; 782 783 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI)) 784 static struct file_operations port_fops = { 785 .llseek = memory_lseek, 786 .read = read_port, 787 .write = write_port, 788 .open = open_port, 789 }; 790 #endif 791 792 static struct file_operations zero_fops = { 793 .llseek = zero_lseek, 794 .read = read_zero, 795 .write = write_zero, 796 .mmap = mmap_zero, 797 }; 798 799 static struct backing_dev_info zero_bdi = { 800 .capabilities = BDI_CAP_MAP_COPY, 801 }; 802 803 static struct file_operations full_fops = { 804 .llseek = full_lseek, 805 .read = read_full, 806 .write = write_full, 807 }; 808 809 #ifdef CONFIG_CRASH_DUMP 810 static struct file_operations oldmem_fops = { 811 .read = read_oldmem, 812 .open = open_oldmem, 813 }; 814 #endif 815 816 static ssize_t kmsg_write(struct file * file, const char __user * buf, 817 size_t count, loff_t *ppos) 818 { 819 char *tmp; 820 int ret; 821 822 tmp = kmalloc(count + 1, GFP_KERNEL); 823 if (tmp == NULL) 824 return -ENOMEM; 825 ret = -EFAULT; 826 if (!copy_from_user(tmp, buf, count)) { 827 tmp[count] = 0; 828 ret = printk("%s", tmp); 829 } 830 kfree(tmp); 831 return ret; 832 } 833 834 static struct file_operations kmsg_fops = { 835 .write = kmsg_write, 836 }; 837 838 static int memory_open(struct inode * inode, struct file * filp) 839 { 840 switch (iminor(inode)) { 841 case 1: 842 filp->f_op = &mem_fops; 843 break; 844 case 2: 845 filp->f_op = &kmem_fops; 846 break; 847 case 3: 848 filp->f_op = &null_fops; 849 break; 850 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI)) 851 case 4: 852 filp->f_op = &port_fops; 853 break; 854 #endif 855 case 5: 856 filp->f_mapping->backing_dev_info = &zero_bdi; 857 filp->f_op = &zero_fops; 858 break; 859 case 7: 860 filp->f_op = &full_fops; 861 break; 862 case 8: 863 filp->f_op = &random_fops; 864 break; 865 case 9: 866 filp->f_op = &urandom_fops; 867 break; 868 case 11: 869 filp->f_op = &kmsg_fops; 870 break; 871 #ifdef CONFIG_CRASH_DUMP 872 case 12: 873 filp->f_op = &oldmem_fops; 874 break; 875 #endif 876 default: 877 return -ENXIO; 878 } 879 if (filp->f_op && filp->f_op->open) 880 return filp->f_op->open(inode,filp); 881 return 0; 882 } 883 884 static struct file_operations memory_fops = { 885 .open = memory_open, /* just a selector for the real open */ 886 }; 887 888 static const struct { 889 unsigned int minor; 890 char *name; 891 umode_t mode; 892 struct file_operations *fops; 893 } devlist[] = { /* list of minor devices */ 894 {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops}, 895 {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops}, 896 {3, "null", S_IRUGO | S_IWUGO, &null_fops}, 897 #if (defined(CONFIG_ISA) || !defined(__mc68000__)) && (!defined(CONFIG_PPC_ISERIES) || defined(CONFIG_PCI)) 898 {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops}, 899 #endif 900 {5, "zero", S_IRUGO | S_IWUGO, &zero_fops}, 901 {7, "full", S_IRUGO | S_IWUGO, &full_fops}, 902 {8, "random", S_IRUGO | S_IWUSR, &random_fops}, 903 {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops}, 904 {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops}, 905 #ifdef CONFIG_CRASH_DUMP 906 {12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops}, 907 #endif 908 }; 909 910 static struct class *mem_class; 911 912 static int __init chr_dev_init(void) 913 { 914 int i; 915 916 if (register_chrdev(MEM_MAJOR,"mem",&memory_fops)) 917 printk("unable to get major %d for memory devs\n", MEM_MAJOR); 918 919 mem_class = class_create(THIS_MODULE, "mem"); 920 for (i = 0; i < ARRAY_SIZE(devlist); i++) { 921 class_device_create(mem_class, NULL, 922 MKDEV(MEM_MAJOR, devlist[i].minor), 923 NULL, devlist[i].name); 924 devfs_mk_cdev(MKDEV(MEM_MAJOR, devlist[i].minor), 925 S_IFCHR | devlist[i].mode, devlist[i].name); 926 } 927 928 return 0; 929 } 930 931 fs_initcall(chr_dev_init); 932