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/ptrace.h> 24 #include <linux/device.h> 25 #include <linux/highmem.h> 26 #include <linux/crash_dump.h> 27 #include <linux/backing-dev.h> 28 #include <linux/bootmem.h> 29 #include <linux/pipe_fs_i.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 if (addr + count > __pa(high_memory)) 94 return 0; 95 96 return 1; 97 } 98 99 static inline int valid_mmap_phys_addr_range(unsigned long addr, size_t size) 100 { 101 return 1; 102 } 103 #endif 104 105 /* 106 * This funcion reads the *physical* memory. The f_pos points directly to the 107 * memory location. 108 */ 109 static ssize_t read_mem(struct file * file, char __user * buf, 110 size_t count, loff_t *ppos) 111 { 112 unsigned long p = *ppos; 113 ssize_t read, sz; 114 char *ptr; 115 116 if (!valid_phys_addr_range(p, count)) 117 return -EFAULT; 118 read = 0; 119 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 120 /* we don't have page 0 mapped on sparc and m68k.. */ 121 if (p < PAGE_SIZE) { 122 sz = PAGE_SIZE - p; 123 if (sz > count) 124 sz = count; 125 if (sz > 0) { 126 if (clear_user(buf, sz)) 127 return -EFAULT; 128 buf += sz; 129 p += sz; 130 count -= sz; 131 read += sz; 132 } 133 } 134 #endif 135 136 while (count > 0) { 137 /* 138 * Handle first page in case it's not aligned 139 */ 140 if (-p & (PAGE_SIZE - 1)) 141 sz = -p & (PAGE_SIZE - 1); 142 else 143 sz = PAGE_SIZE; 144 145 sz = min_t(unsigned long, sz, count); 146 147 /* 148 * On ia64 if a page has been mapped somewhere as 149 * uncached, then it must also be accessed uncached 150 * by the kernel or data corruption may occur 151 */ 152 ptr = xlate_dev_mem_ptr(p); 153 154 if (copy_to_user(buf, ptr, sz)) 155 return -EFAULT; 156 buf += sz; 157 p += sz; 158 count -= sz; 159 read += sz; 160 } 161 162 *ppos += read; 163 return read; 164 } 165 166 static ssize_t write_mem(struct file * file, const char __user * buf, 167 size_t count, loff_t *ppos) 168 { 169 unsigned long p = *ppos; 170 ssize_t written, sz; 171 unsigned long copied; 172 void *ptr; 173 174 if (!valid_phys_addr_range(p, count)) 175 return -EFAULT; 176 177 written = 0; 178 179 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 180 /* we don't have page 0 mapped on sparc and m68k.. */ 181 if (p < PAGE_SIZE) { 182 unsigned long sz = PAGE_SIZE - p; 183 if (sz > count) 184 sz = count; 185 /* Hmm. Do something? */ 186 buf += sz; 187 p += sz; 188 count -= sz; 189 written += sz; 190 } 191 #endif 192 193 while (count > 0) { 194 /* 195 * Handle first page in case it's not aligned 196 */ 197 if (-p & (PAGE_SIZE - 1)) 198 sz = -p & (PAGE_SIZE - 1); 199 else 200 sz = PAGE_SIZE; 201 202 sz = min_t(unsigned long, sz, count); 203 204 /* 205 * On ia64 if a page has been mapped somewhere as 206 * uncached, then it must also be accessed uncached 207 * by the kernel or data corruption may occur 208 */ 209 ptr = xlate_dev_mem_ptr(p); 210 211 copied = copy_from_user(ptr, buf, sz); 212 if (copied) { 213 written += sz - copied; 214 if (written) 215 break; 216 return -EFAULT; 217 } 218 buf += sz; 219 p += sz; 220 count -= sz; 221 written += sz; 222 } 223 224 *ppos += written; 225 return written; 226 } 227 228 #ifndef __HAVE_PHYS_MEM_ACCESS_PROT 229 static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 230 unsigned long size, pgprot_t vma_prot) 231 { 232 #ifdef pgprot_noncached 233 unsigned long offset = pfn << PAGE_SHIFT; 234 235 if (uncached_access(file, offset)) 236 return pgprot_noncached(vma_prot); 237 #endif 238 return vma_prot; 239 } 240 #endif 241 242 static int mmap_mem(struct file * file, struct vm_area_struct * vma) 243 { 244 size_t size = vma->vm_end - vma->vm_start; 245 246 if (!valid_mmap_phys_addr_range(vma->vm_pgoff << PAGE_SHIFT, size)) 247 return -EINVAL; 248 249 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, 250 size, 251 vma->vm_page_prot); 252 253 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ 254 if (remap_pfn_range(vma, 255 vma->vm_start, 256 vma->vm_pgoff, 257 size, 258 vma->vm_page_prot)) 259 return -EAGAIN; 260 return 0; 261 } 262 263 static int mmap_kmem(struct file * file, struct vm_area_struct * vma) 264 { 265 unsigned long pfn; 266 267 /* Turn a kernel-virtual address into a physical page frame */ 268 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; 269 270 /* 271 * RED-PEN: on some architectures there is more mapped memory 272 * than available in mem_map which pfn_valid checks 273 * for. Perhaps should add a new macro here. 274 * 275 * RED-PEN: vmalloc is not supported right now. 276 */ 277 if (!pfn_valid(pfn)) 278 return -EIO; 279 280 vma->vm_pgoff = pfn; 281 return mmap_mem(file, vma); 282 } 283 284 #ifdef CONFIG_CRASH_DUMP 285 /* 286 * Read memory corresponding to the old kernel. 287 */ 288 static ssize_t read_oldmem(struct file *file, char __user *buf, 289 size_t count, loff_t *ppos) 290 { 291 unsigned long pfn, offset; 292 size_t read = 0, csize; 293 int rc = 0; 294 295 while (count) { 296 pfn = *ppos / PAGE_SIZE; 297 if (pfn > saved_max_pfn) 298 return read; 299 300 offset = (unsigned long)(*ppos % PAGE_SIZE); 301 if (count > PAGE_SIZE - offset) 302 csize = PAGE_SIZE - offset; 303 else 304 csize = count; 305 306 rc = copy_oldmem_page(pfn, buf, csize, offset, 1); 307 if (rc < 0) 308 return rc; 309 buf += csize; 310 *ppos += csize; 311 read += csize; 312 count -= csize; 313 } 314 return read; 315 } 316 #endif 317 318 extern long vread(char *buf, char *addr, unsigned long count); 319 extern long vwrite(char *buf, char *addr, unsigned long count); 320 321 /* 322 * This function reads the *virtual* memory as seen by the kernel. 323 */ 324 static ssize_t read_kmem(struct file *file, char __user *buf, 325 size_t count, loff_t *ppos) 326 { 327 unsigned long p = *ppos; 328 ssize_t low_count, read, sz; 329 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ 330 331 read = 0; 332 if (p < (unsigned long) high_memory) { 333 low_count = count; 334 if (count > (unsigned long) high_memory - p) 335 low_count = (unsigned long) high_memory - p; 336 337 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 338 /* we don't have page 0 mapped on sparc and m68k.. */ 339 if (p < PAGE_SIZE && low_count > 0) { 340 size_t tmp = PAGE_SIZE - p; 341 if (tmp > low_count) tmp = low_count; 342 if (clear_user(buf, tmp)) 343 return -EFAULT; 344 buf += tmp; 345 p += tmp; 346 read += tmp; 347 low_count -= tmp; 348 count -= tmp; 349 } 350 #endif 351 while (low_count > 0) { 352 /* 353 * Handle first page in case it's not aligned 354 */ 355 if (-p & (PAGE_SIZE - 1)) 356 sz = -p & (PAGE_SIZE - 1); 357 else 358 sz = PAGE_SIZE; 359 360 sz = min_t(unsigned long, sz, low_count); 361 362 /* 363 * On ia64 if a page has been mapped somewhere as 364 * uncached, then it must also be accessed uncached 365 * by the kernel or data corruption may occur 366 */ 367 kbuf = xlate_dev_kmem_ptr((char *)p); 368 369 if (copy_to_user(buf, kbuf, sz)) 370 return -EFAULT; 371 buf += sz; 372 p += sz; 373 read += sz; 374 low_count -= sz; 375 count -= sz; 376 } 377 } 378 379 if (count > 0) { 380 kbuf = (char *)__get_free_page(GFP_KERNEL); 381 if (!kbuf) 382 return -ENOMEM; 383 while (count > 0) { 384 int len = count; 385 386 if (len > PAGE_SIZE) 387 len = PAGE_SIZE; 388 len = vread(kbuf, (char *)p, len); 389 if (!len) 390 break; 391 if (copy_to_user(buf, kbuf, len)) { 392 free_page((unsigned long)kbuf); 393 return -EFAULT; 394 } 395 count -= len; 396 buf += len; 397 read += len; 398 p += len; 399 } 400 free_page((unsigned long)kbuf); 401 } 402 *ppos = p; 403 return read; 404 } 405 406 407 static inline ssize_t 408 do_write_kmem(void *p, unsigned long realp, const char __user * buf, 409 size_t count, loff_t *ppos) 410 { 411 ssize_t written, sz; 412 unsigned long copied; 413 414 written = 0; 415 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 416 /* we don't have page 0 mapped on sparc and m68k.. */ 417 if (realp < PAGE_SIZE) { 418 unsigned long sz = PAGE_SIZE - realp; 419 if (sz > count) 420 sz = count; 421 /* Hmm. Do something? */ 422 buf += sz; 423 p += sz; 424 realp += sz; 425 count -= sz; 426 written += sz; 427 } 428 #endif 429 430 while (count > 0) { 431 char *ptr; 432 /* 433 * Handle first page in case it's not aligned 434 */ 435 if (-realp & (PAGE_SIZE - 1)) 436 sz = -realp & (PAGE_SIZE - 1); 437 else 438 sz = PAGE_SIZE; 439 440 sz = min_t(unsigned long, sz, count); 441 442 /* 443 * On ia64 if a page has been mapped somewhere as 444 * uncached, then it must also be accessed uncached 445 * by the kernel or data corruption may occur 446 */ 447 ptr = xlate_dev_kmem_ptr(p); 448 449 copied = copy_from_user(ptr, buf, sz); 450 if (copied) { 451 written += sz - copied; 452 if (written) 453 break; 454 return -EFAULT; 455 } 456 buf += sz; 457 p += sz; 458 realp += sz; 459 count -= sz; 460 written += sz; 461 } 462 463 *ppos += written; 464 return written; 465 } 466 467 468 /* 469 * This function writes to the *virtual* memory as seen by the kernel. 470 */ 471 static ssize_t write_kmem(struct file * file, const char __user * buf, 472 size_t count, loff_t *ppos) 473 { 474 unsigned long p = *ppos; 475 ssize_t wrote = 0; 476 ssize_t virtr = 0; 477 ssize_t written; 478 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ 479 480 if (p < (unsigned long) high_memory) { 481 482 wrote = count; 483 if (count > (unsigned long) high_memory - p) 484 wrote = (unsigned long) high_memory - p; 485 486 written = do_write_kmem((void*)p, p, buf, wrote, ppos); 487 if (written != wrote) 488 return written; 489 wrote = written; 490 p += wrote; 491 buf += wrote; 492 count -= wrote; 493 } 494 495 if (count > 0) { 496 kbuf = (char *)__get_free_page(GFP_KERNEL); 497 if (!kbuf) 498 return wrote ? wrote : -ENOMEM; 499 while (count > 0) { 500 int len = count; 501 502 if (len > PAGE_SIZE) 503 len = PAGE_SIZE; 504 if (len) { 505 written = copy_from_user(kbuf, buf, len); 506 if (written) { 507 if (wrote + virtr) 508 break; 509 free_page((unsigned long)kbuf); 510 return -EFAULT; 511 } 512 } 513 len = vwrite(kbuf, (char *)p, len); 514 count -= len; 515 buf += len; 516 virtr += len; 517 p += len; 518 } 519 free_page((unsigned long)kbuf); 520 } 521 522 *ppos = p; 523 return virtr + wrote; 524 } 525 526 #if defined(CONFIG_ISA) || !defined(__mc68000__) 527 static ssize_t read_port(struct file * file, char __user * buf, 528 size_t count, loff_t *ppos) 529 { 530 unsigned long i = *ppos; 531 char __user *tmp = buf; 532 533 if (!access_ok(VERIFY_WRITE, buf, count)) 534 return -EFAULT; 535 while (count-- > 0 && i < 65536) { 536 if (__put_user(inb(i),tmp) < 0) 537 return -EFAULT; 538 i++; 539 tmp++; 540 } 541 *ppos = i; 542 return tmp-buf; 543 } 544 545 static ssize_t write_port(struct file * file, const char __user * buf, 546 size_t count, loff_t *ppos) 547 { 548 unsigned long i = *ppos; 549 const char __user * tmp = buf; 550 551 if (!access_ok(VERIFY_READ,buf,count)) 552 return -EFAULT; 553 while (count-- > 0 && i < 65536) { 554 char c; 555 if (__get_user(c, tmp)) { 556 if (tmp > buf) 557 break; 558 return -EFAULT; 559 } 560 outb(c,i); 561 i++; 562 tmp++; 563 } 564 *ppos = i; 565 return tmp-buf; 566 } 567 #endif 568 569 static ssize_t read_null(struct file * file, char __user * buf, 570 size_t count, loff_t *ppos) 571 { 572 return 0; 573 } 574 575 static ssize_t write_null(struct file * file, const char __user * buf, 576 size_t count, loff_t *ppos) 577 { 578 return count; 579 } 580 581 static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, 582 struct splice_desc *sd) 583 { 584 return sd->len; 585 } 586 587 static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out, 588 loff_t *ppos, size_t len, unsigned int flags) 589 { 590 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); 591 } 592 593 #ifdef CONFIG_MMU 594 /* 595 * For fun, we are using the MMU for this. 596 */ 597 static inline size_t read_zero_pagealigned(char __user * buf, size_t size) 598 { 599 struct mm_struct *mm; 600 struct vm_area_struct * vma; 601 unsigned long addr=(unsigned long)buf; 602 603 mm = current->mm; 604 /* Oops, this was forgotten before. -ben */ 605 down_read(&mm->mmap_sem); 606 607 /* For private mappings, just map in zero pages. */ 608 for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) { 609 unsigned long count; 610 611 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0) 612 goto out_up; 613 if (vma->vm_flags & (VM_SHARED | VM_HUGETLB)) 614 break; 615 count = vma->vm_end - addr; 616 if (count > size) 617 count = size; 618 619 zap_page_range(vma, addr, count, NULL); 620 zeromap_page_range(vma, addr, count, PAGE_COPY); 621 622 size -= count; 623 buf += count; 624 addr += count; 625 if (size == 0) 626 goto out_up; 627 } 628 629 up_read(&mm->mmap_sem); 630 631 /* The shared case is hard. Let's do the conventional zeroing. */ 632 do { 633 unsigned long unwritten = clear_user(buf, PAGE_SIZE); 634 if (unwritten) 635 return size + unwritten - PAGE_SIZE; 636 cond_resched(); 637 buf += PAGE_SIZE; 638 size -= PAGE_SIZE; 639 } while (size); 640 641 return size; 642 out_up: 643 up_read(&mm->mmap_sem); 644 return size; 645 } 646 647 static ssize_t read_zero(struct file * file, char __user * buf, 648 size_t count, loff_t *ppos) 649 { 650 unsigned long left, unwritten, written = 0; 651 652 if (!count) 653 return 0; 654 655 if (!access_ok(VERIFY_WRITE, buf, count)) 656 return -EFAULT; 657 658 left = count; 659 660 /* do we want to be clever? Arbitrary cut-off */ 661 if (count >= PAGE_SIZE*4) { 662 unsigned long partial; 663 664 /* How much left of the page? */ 665 partial = (PAGE_SIZE-1) & -(unsigned long) buf; 666 unwritten = clear_user(buf, partial); 667 written = partial - unwritten; 668 if (unwritten) 669 goto out; 670 left -= partial; 671 buf += partial; 672 unwritten = read_zero_pagealigned(buf, left & PAGE_MASK); 673 written += (left & PAGE_MASK) - unwritten; 674 if (unwritten) 675 goto out; 676 buf += left & PAGE_MASK; 677 left &= ~PAGE_MASK; 678 } 679 unwritten = clear_user(buf, left); 680 written += left - unwritten; 681 out: 682 return written ? written : -EFAULT; 683 } 684 685 static int mmap_zero(struct file * file, struct vm_area_struct * vma) 686 { 687 if (vma->vm_flags & VM_SHARED) 688 return shmem_zero_setup(vma); 689 if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot)) 690 return -EAGAIN; 691 return 0; 692 } 693 #else /* CONFIG_MMU */ 694 static ssize_t read_zero(struct file * file, char * buf, 695 size_t count, loff_t *ppos) 696 { 697 size_t todo = count; 698 699 while (todo) { 700 size_t chunk = todo; 701 702 if (chunk > 4096) 703 chunk = 4096; /* Just for latency reasons */ 704 if (clear_user(buf, chunk)) 705 return -EFAULT; 706 buf += chunk; 707 todo -= chunk; 708 cond_resched(); 709 } 710 return count; 711 } 712 713 static int mmap_zero(struct file * file, struct vm_area_struct * vma) 714 { 715 return -ENOSYS; 716 } 717 #endif /* CONFIG_MMU */ 718 719 static ssize_t write_full(struct file * file, const char __user * buf, 720 size_t count, loff_t *ppos) 721 { 722 return -ENOSPC; 723 } 724 725 /* 726 * Special lseek() function for /dev/null and /dev/zero. Most notably, you 727 * can fopen() both devices with "a" now. This was previously impossible. 728 * -- SRB. 729 */ 730 731 static loff_t null_lseek(struct file * file, loff_t offset, int orig) 732 { 733 return file->f_pos = 0; 734 } 735 736 /* 737 * The memory devices use the full 32/64 bits of the offset, and so we cannot 738 * check against negative addresses: they are ok. The return value is weird, 739 * though, in that case (0). 740 * 741 * also note that seeking relative to the "end of file" isn't supported: 742 * it has no meaning, so it returns -EINVAL. 743 */ 744 static loff_t memory_lseek(struct file * file, loff_t offset, int orig) 745 { 746 loff_t ret; 747 748 mutex_lock(&file->f_dentry->d_inode->i_mutex); 749 switch (orig) { 750 case 0: 751 file->f_pos = offset; 752 ret = file->f_pos; 753 force_successful_syscall_return(); 754 break; 755 case 1: 756 file->f_pos += offset; 757 ret = file->f_pos; 758 force_successful_syscall_return(); 759 break; 760 default: 761 ret = -EINVAL; 762 } 763 mutex_unlock(&file->f_dentry->d_inode->i_mutex); 764 return ret; 765 } 766 767 static int open_port(struct inode * inode, struct file * filp) 768 { 769 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; 770 } 771 772 #define zero_lseek null_lseek 773 #define full_lseek null_lseek 774 #define write_zero write_null 775 #define read_full read_zero 776 #define open_mem open_port 777 #define open_kmem open_mem 778 #define open_oldmem open_mem 779 780 static struct file_operations mem_fops = { 781 .llseek = memory_lseek, 782 .read = read_mem, 783 .write = write_mem, 784 .mmap = mmap_mem, 785 .open = open_mem, 786 }; 787 788 static struct file_operations kmem_fops = { 789 .llseek = memory_lseek, 790 .read = read_kmem, 791 .write = write_kmem, 792 .mmap = mmap_kmem, 793 .open = open_kmem, 794 }; 795 796 static struct file_operations null_fops = { 797 .llseek = null_lseek, 798 .read = read_null, 799 .write = write_null, 800 .splice_write = splice_write_null, 801 }; 802 803 #if defined(CONFIG_ISA) || !defined(__mc68000__) 804 static struct file_operations port_fops = { 805 .llseek = memory_lseek, 806 .read = read_port, 807 .write = write_port, 808 .open = open_port, 809 }; 810 #endif 811 812 static struct file_operations zero_fops = { 813 .llseek = zero_lseek, 814 .read = read_zero, 815 .write = write_zero, 816 .mmap = mmap_zero, 817 }; 818 819 static struct backing_dev_info zero_bdi = { 820 .capabilities = BDI_CAP_MAP_COPY, 821 }; 822 823 static struct file_operations full_fops = { 824 .llseek = full_lseek, 825 .read = read_full, 826 .write = write_full, 827 }; 828 829 #ifdef CONFIG_CRASH_DUMP 830 static struct file_operations oldmem_fops = { 831 .read = read_oldmem, 832 .open = open_oldmem, 833 }; 834 #endif 835 836 static ssize_t kmsg_write(struct file * file, const char __user * buf, 837 size_t count, loff_t *ppos) 838 { 839 char *tmp; 840 ssize_t ret; 841 842 tmp = kmalloc(count + 1, GFP_KERNEL); 843 if (tmp == NULL) 844 return -ENOMEM; 845 ret = -EFAULT; 846 if (!copy_from_user(tmp, buf, count)) { 847 tmp[count] = 0; 848 ret = printk("%s", tmp); 849 if (ret > count) 850 /* printk can add a prefix */ 851 ret = count; 852 } 853 kfree(tmp); 854 return ret; 855 } 856 857 static struct file_operations kmsg_fops = { 858 .write = kmsg_write, 859 }; 860 861 static int memory_open(struct inode * inode, struct file * filp) 862 { 863 switch (iminor(inode)) { 864 case 1: 865 filp->f_op = &mem_fops; 866 break; 867 case 2: 868 filp->f_op = &kmem_fops; 869 break; 870 case 3: 871 filp->f_op = &null_fops; 872 break; 873 #if defined(CONFIG_ISA) || !defined(__mc68000__) 874 case 4: 875 filp->f_op = &port_fops; 876 break; 877 #endif 878 case 5: 879 filp->f_mapping->backing_dev_info = &zero_bdi; 880 filp->f_op = &zero_fops; 881 break; 882 case 7: 883 filp->f_op = &full_fops; 884 break; 885 case 8: 886 filp->f_op = &random_fops; 887 break; 888 case 9: 889 filp->f_op = &urandom_fops; 890 break; 891 case 11: 892 filp->f_op = &kmsg_fops; 893 break; 894 #ifdef CONFIG_CRASH_DUMP 895 case 12: 896 filp->f_op = &oldmem_fops; 897 break; 898 #endif 899 default: 900 return -ENXIO; 901 } 902 if (filp->f_op && filp->f_op->open) 903 return filp->f_op->open(inode,filp); 904 return 0; 905 } 906 907 static struct file_operations memory_fops = { 908 .open = memory_open, /* just a selector for the real open */ 909 }; 910 911 static const struct { 912 unsigned int minor; 913 char *name; 914 umode_t mode; 915 const struct file_operations *fops; 916 } devlist[] = { /* list of minor devices */ 917 {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops}, 918 {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops}, 919 {3, "null", S_IRUGO | S_IWUGO, &null_fops}, 920 #if defined(CONFIG_ISA) || !defined(__mc68000__) 921 {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops}, 922 #endif 923 {5, "zero", S_IRUGO | S_IWUGO, &zero_fops}, 924 {7, "full", S_IRUGO | S_IWUGO, &full_fops}, 925 {8, "random", S_IRUGO | S_IWUSR, &random_fops}, 926 {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops}, 927 {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops}, 928 #ifdef CONFIG_CRASH_DUMP 929 {12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops}, 930 #endif 931 }; 932 933 static struct class *mem_class; 934 935 static int __init chr_dev_init(void) 936 { 937 int i; 938 939 if (register_chrdev(MEM_MAJOR,"mem",&memory_fops)) 940 printk("unable to get major %d for memory devs\n", MEM_MAJOR); 941 942 mem_class = class_create(THIS_MODULE, "mem"); 943 for (i = 0; i < ARRAY_SIZE(devlist); i++) 944 class_device_create(mem_class, NULL, 945 MKDEV(MEM_MAJOR, devlist[i].minor), 946 NULL, devlist[i].name); 947 948 return 0; 949 } 950 951 fs_initcall(chr_dev_init); 952