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/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/smp_lock.h> 22 #include <linux/ptrace.h> 23 #include <linux/device.h> 24 #include <linux/highmem.h> 25 #include <linux/crash_dump.h> 26 #include <linux/backing-dev.h> 27 #include <linux/bootmem.h> 28 #include <linux/pipe_fs_i.h> 29 #include <linux/pfn.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 pfn, 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 #ifndef CONFIG_MMU 243 static unsigned long get_unmapped_area_mem(struct file *file, 244 unsigned long addr, 245 unsigned long len, 246 unsigned long pgoff, 247 unsigned long flags) 248 { 249 if (!valid_mmap_phys_addr_range(pgoff, len)) 250 return (unsigned long) -EINVAL; 251 return pgoff; 252 } 253 254 /* can't do an in-place private mapping if there's no MMU */ 255 static inline int private_mapping_ok(struct vm_area_struct *vma) 256 { 257 return vma->vm_flags & VM_MAYSHARE; 258 } 259 #else 260 #define get_unmapped_area_mem NULL 261 262 static inline int private_mapping_ok(struct vm_area_struct *vma) 263 { 264 return 1; 265 } 266 #endif 267 268 static int mmap_mem(struct file * file, struct vm_area_struct * vma) 269 { 270 size_t size = vma->vm_end - vma->vm_start; 271 272 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) 273 return -EINVAL; 274 275 if (!private_mapping_ok(vma)) 276 return -ENOSYS; 277 278 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, 279 size, 280 vma->vm_page_prot); 281 282 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ 283 if (remap_pfn_range(vma, 284 vma->vm_start, 285 vma->vm_pgoff, 286 size, 287 vma->vm_page_prot)) 288 return -EAGAIN; 289 return 0; 290 } 291 292 static int mmap_kmem(struct file * file, struct vm_area_struct * vma) 293 { 294 unsigned long pfn; 295 296 /* Turn a pfn offset into an absolute pfn */ 297 pfn = PFN_DOWN(virt_to_phys((void *)PAGE_OFFSET)) + vma->vm_pgoff; 298 299 /* 300 * RED-PEN: on some architectures there is more mapped memory 301 * than available in mem_map which pfn_valid checks 302 * for. Perhaps should add a new macro here. 303 * 304 * RED-PEN: vmalloc is not supported right now. 305 */ 306 if (!pfn_valid(pfn)) 307 return -EIO; 308 309 vma->vm_pgoff = pfn; 310 return mmap_mem(file, vma); 311 } 312 313 #ifdef CONFIG_CRASH_DUMP 314 /* 315 * Read memory corresponding to the old kernel. 316 */ 317 static ssize_t read_oldmem(struct file *file, char __user *buf, 318 size_t count, loff_t *ppos) 319 { 320 unsigned long pfn, offset; 321 size_t read = 0, csize; 322 int rc = 0; 323 324 while (count) { 325 pfn = *ppos / PAGE_SIZE; 326 if (pfn > saved_max_pfn) 327 return read; 328 329 offset = (unsigned long)(*ppos % PAGE_SIZE); 330 if (count > PAGE_SIZE - offset) 331 csize = PAGE_SIZE - offset; 332 else 333 csize = count; 334 335 rc = copy_oldmem_page(pfn, buf, csize, offset, 1); 336 if (rc < 0) 337 return rc; 338 buf += csize; 339 *ppos += csize; 340 read += csize; 341 count -= csize; 342 } 343 return read; 344 } 345 #endif 346 347 extern long vread(char *buf, char *addr, unsigned long count); 348 extern long vwrite(char *buf, char *addr, unsigned long count); 349 350 /* 351 * This function reads the *virtual* memory as seen by the kernel. 352 */ 353 static ssize_t read_kmem(struct file *file, char __user *buf, 354 size_t count, loff_t *ppos) 355 { 356 unsigned long p = *ppos; 357 ssize_t low_count, read, sz; 358 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ 359 360 read = 0; 361 if (p < (unsigned long) high_memory) { 362 low_count = count; 363 if (count > (unsigned long) high_memory - p) 364 low_count = (unsigned long) high_memory - p; 365 366 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 367 /* we don't have page 0 mapped on sparc and m68k.. */ 368 if (p < PAGE_SIZE && low_count > 0) { 369 size_t tmp = PAGE_SIZE - p; 370 if (tmp > low_count) tmp = low_count; 371 if (clear_user(buf, tmp)) 372 return -EFAULT; 373 buf += tmp; 374 p += tmp; 375 read += tmp; 376 low_count -= tmp; 377 count -= tmp; 378 } 379 #endif 380 while (low_count > 0) { 381 /* 382 * Handle first page in case it's not aligned 383 */ 384 if (-p & (PAGE_SIZE - 1)) 385 sz = -p & (PAGE_SIZE - 1); 386 else 387 sz = PAGE_SIZE; 388 389 sz = min_t(unsigned long, sz, low_count); 390 391 /* 392 * On ia64 if a page has been mapped somewhere as 393 * uncached, then it must also be accessed uncached 394 * by the kernel or data corruption may occur 395 */ 396 kbuf = xlate_dev_kmem_ptr((char *)p); 397 398 if (copy_to_user(buf, kbuf, sz)) 399 return -EFAULT; 400 buf += sz; 401 p += sz; 402 read += sz; 403 low_count -= sz; 404 count -= sz; 405 } 406 } 407 408 if (count > 0) { 409 kbuf = (char *)__get_free_page(GFP_KERNEL); 410 if (!kbuf) 411 return -ENOMEM; 412 while (count > 0) { 413 int len = count; 414 415 if (len > PAGE_SIZE) 416 len = PAGE_SIZE; 417 len = vread(kbuf, (char *)p, len); 418 if (!len) 419 break; 420 if (copy_to_user(buf, kbuf, len)) { 421 free_page((unsigned long)kbuf); 422 return -EFAULT; 423 } 424 count -= len; 425 buf += len; 426 read += len; 427 p += len; 428 } 429 free_page((unsigned long)kbuf); 430 } 431 *ppos = p; 432 return read; 433 } 434 435 436 static inline ssize_t 437 do_write_kmem(void *p, unsigned long realp, const char __user * buf, 438 size_t count, loff_t *ppos) 439 { 440 ssize_t written, sz; 441 unsigned long copied; 442 443 written = 0; 444 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 445 /* we don't have page 0 mapped on sparc and m68k.. */ 446 if (realp < PAGE_SIZE) { 447 unsigned long sz = PAGE_SIZE - realp; 448 if (sz > count) 449 sz = count; 450 /* Hmm. Do something? */ 451 buf += sz; 452 p += sz; 453 realp += sz; 454 count -= sz; 455 written += sz; 456 } 457 #endif 458 459 while (count > 0) { 460 char *ptr; 461 /* 462 * Handle first page in case it's not aligned 463 */ 464 if (-realp & (PAGE_SIZE - 1)) 465 sz = -realp & (PAGE_SIZE - 1); 466 else 467 sz = PAGE_SIZE; 468 469 sz = min_t(unsigned long, sz, count); 470 471 /* 472 * On ia64 if a page has been mapped somewhere as 473 * uncached, then it must also be accessed uncached 474 * by the kernel or data corruption may occur 475 */ 476 ptr = xlate_dev_kmem_ptr(p); 477 478 copied = copy_from_user(ptr, buf, sz); 479 if (copied) { 480 written += sz - copied; 481 if (written) 482 break; 483 return -EFAULT; 484 } 485 buf += sz; 486 p += sz; 487 realp += sz; 488 count -= sz; 489 written += sz; 490 } 491 492 *ppos += written; 493 return written; 494 } 495 496 497 /* 498 * This function writes to the *virtual* memory as seen by the kernel. 499 */ 500 static ssize_t write_kmem(struct file * file, const char __user * buf, 501 size_t count, loff_t *ppos) 502 { 503 unsigned long p = *ppos; 504 ssize_t wrote = 0; 505 ssize_t virtr = 0; 506 ssize_t written; 507 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ 508 509 if (p < (unsigned long) high_memory) { 510 511 wrote = count; 512 if (count > (unsigned long) high_memory - p) 513 wrote = (unsigned long) high_memory - p; 514 515 written = do_write_kmem((void*)p, p, buf, wrote, ppos); 516 if (written != wrote) 517 return written; 518 wrote = written; 519 p += wrote; 520 buf += wrote; 521 count -= wrote; 522 } 523 524 if (count > 0) { 525 kbuf = (char *)__get_free_page(GFP_KERNEL); 526 if (!kbuf) 527 return wrote ? wrote : -ENOMEM; 528 while (count > 0) { 529 int len = count; 530 531 if (len > PAGE_SIZE) 532 len = PAGE_SIZE; 533 if (len) { 534 written = copy_from_user(kbuf, buf, len); 535 if (written) { 536 if (wrote + virtr) 537 break; 538 free_page((unsigned long)kbuf); 539 return -EFAULT; 540 } 541 } 542 len = vwrite(kbuf, (char *)p, len); 543 count -= len; 544 buf += len; 545 virtr += len; 546 p += len; 547 } 548 free_page((unsigned long)kbuf); 549 } 550 551 *ppos = p; 552 return virtr + wrote; 553 } 554 555 #if (defined(CONFIG_ISA) || defined(CONFIG_PCI)) && !defined(__mc68000__) 556 static 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 } 573 574 static 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 if (__get_user(c, tmp)) { 585 if (tmp > buf) 586 break; 587 return -EFAULT; 588 } 589 outb(c,i); 590 i++; 591 tmp++; 592 } 593 *ppos = i; 594 return tmp-buf; 595 } 596 #endif 597 598 static ssize_t read_null(struct file * file, char __user * buf, 599 size_t count, loff_t *ppos) 600 { 601 return 0; 602 } 603 604 static ssize_t write_null(struct file * file, const char __user * buf, 605 size_t count, loff_t *ppos) 606 { 607 return count; 608 } 609 610 static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, 611 struct splice_desc *sd) 612 { 613 return sd->len; 614 } 615 616 static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out, 617 loff_t *ppos, size_t len, unsigned int flags) 618 { 619 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); 620 } 621 622 #ifdef CONFIG_MMU 623 /* 624 * For fun, we are using the MMU for this. 625 */ 626 static inline size_t read_zero_pagealigned(char __user * buf, size_t size) 627 { 628 struct mm_struct *mm; 629 struct vm_area_struct * vma; 630 unsigned long addr=(unsigned long)buf; 631 632 mm = current->mm; 633 /* Oops, this was forgotten before. -ben */ 634 down_read(&mm->mmap_sem); 635 636 /* For private mappings, just map in zero pages. */ 637 for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) { 638 unsigned long count; 639 640 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0) 641 goto out_up; 642 if (vma->vm_flags & (VM_SHARED | VM_HUGETLB)) 643 break; 644 count = vma->vm_end - addr; 645 if (count > size) 646 count = size; 647 648 zap_page_range(vma, addr, count, NULL); 649 zeromap_page_range(vma, addr, count, PAGE_COPY); 650 651 size -= count; 652 buf += count; 653 addr += count; 654 if (size == 0) 655 goto out_up; 656 } 657 658 up_read(&mm->mmap_sem); 659 660 /* The shared case is hard. Let's do the conventional zeroing. */ 661 do { 662 unsigned long unwritten = clear_user(buf, PAGE_SIZE); 663 if (unwritten) 664 return size + unwritten - PAGE_SIZE; 665 cond_resched(); 666 buf += PAGE_SIZE; 667 size -= PAGE_SIZE; 668 } while (size); 669 670 return size; 671 out_up: 672 up_read(&mm->mmap_sem); 673 return size; 674 } 675 676 static ssize_t read_zero(struct file * file, char __user * buf, 677 size_t count, loff_t *ppos) 678 { 679 unsigned long left, unwritten, written = 0; 680 681 if (!count) 682 return 0; 683 684 if (!access_ok(VERIFY_WRITE, buf, count)) 685 return -EFAULT; 686 687 left = count; 688 689 /* do we want to be clever? Arbitrary cut-off */ 690 if (count >= PAGE_SIZE*4) { 691 unsigned long partial; 692 693 /* How much left of the page? */ 694 partial = (PAGE_SIZE-1) & -(unsigned long) buf; 695 unwritten = clear_user(buf, partial); 696 written = partial - unwritten; 697 if (unwritten) 698 goto out; 699 left -= partial; 700 buf += partial; 701 unwritten = read_zero_pagealigned(buf, left & PAGE_MASK); 702 written += (left & PAGE_MASK) - unwritten; 703 if (unwritten) 704 goto out; 705 buf += left & PAGE_MASK; 706 left &= ~PAGE_MASK; 707 } 708 unwritten = clear_user(buf, left); 709 written += left - unwritten; 710 out: 711 return written ? written : -EFAULT; 712 } 713 714 static int mmap_zero(struct file * file, struct vm_area_struct * vma) 715 { 716 if (vma->vm_flags & VM_SHARED) 717 return shmem_zero_setup(vma); 718 if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot)) 719 return -EAGAIN; 720 return 0; 721 } 722 #else /* CONFIG_MMU */ 723 static ssize_t read_zero(struct file * file, char * buf, 724 size_t count, loff_t *ppos) 725 { 726 size_t todo = count; 727 728 while (todo) { 729 size_t chunk = todo; 730 731 if (chunk > 4096) 732 chunk = 4096; /* Just for latency reasons */ 733 if (clear_user(buf, chunk)) 734 return -EFAULT; 735 buf += chunk; 736 todo -= chunk; 737 cond_resched(); 738 } 739 return count; 740 } 741 742 static int mmap_zero(struct file * file, struct vm_area_struct * vma) 743 { 744 return -ENOSYS; 745 } 746 #endif /* CONFIG_MMU */ 747 748 static ssize_t write_full(struct file * file, const char __user * buf, 749 size_t count, loff_t *ppos) 750 { 751 return -ENOSPC; 752 } 753 754 /* 755 * Special lseek() function for /dev/null and /dev/zero. Most notably, you 756 * can fopen() both devices with "a" now. This was previously impossible. 757 * -- SRB. 758 */ 759 760 static loff_t null_lseek(struct file * file, loff_t offset, int orig) 761 { 762 return file->f_pos = 0; 763 } 764 765 /* 766 * The memory devices use the full 32/64 bits of the offset, and so we cannot 767 * check against negative addresses: they are ok. The return value is weird, 768 * though, in that case (0). 769 * 770 * also note that seeking relative to the "end of file" isn't supported: 771 * it has no meaning, so it returns -EINVAL. 772 */ 773 static loff_t memory_lseek(struct file * file, loff_t offset, int orig) 774 { 775 loff_t ret; 776 777 mutex_lock(&file->f_path.dentry->d_inode->i_mutex); 778 switch (orig) { 779 case 0: 780 file->f_pos = offset; 781 ret = file->f_pos; 782 force_successful_syscall_return(); 783 break; 784 case 1: 785 file->f_pos += offset; 786 ret = file->f_pos; 787 force_successful_syscall_return(); 788 break; 789 default: 790 ret = -EINVAL; 791 } 792 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); 793 return ret; 794 } 795 796 static int open_port(struct inode * inode, struct file * filp) 797 { 798 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; 799 } 800 801 #define zero_lseek null_lseek 802 #define full_lseek null_lseek 803 #define write_zero write_null 804 #define read_full read_zero 805 #define open_mem open_port 806 #define open_kmem open_mem 807 #define open_oldmem open_mem 808 809 static const struct file_operations mem_fops = { 810 .llseek = memory_lseek, 811 .read = read_mem, 812 .write = write_mem, 813 .mmap = mmap_mem, 814 .open = open_mem, 815 .get_unmapped_area = get_unmapped_area_mem, 816 }; 817 818 static const struct file_operations kmem_fops = { 819 .llseek = memory_lseek, 820 .read = read_kmem, 821 .write = write_kmem, 822 .mmap = mmap_kmem, 823 .open = open_kmem, 824 .get_unmapped_area = get_unmapped_area_mem, 825 }; 826 827 static const struct file_operations null_fops = { 828 .llseek = null_lseek, 829 .read = read_null, 830 .write = write_null, 831 .splice_write = splice_write_null, 832 }; 833 834 #if (defined(CONFIG_ISA) || defined(CONFIG_PCI)) && !defined(__mc68000__) 835 static const struct file_operations port_fops = { 836 .llseek = memory_lseek, 837 .read = read_port, 838 .write = write_port, 839 .open = open_port, 840 }; 841 #endif 842 843 static const struct file_operations zero_fops = { 844 .llseek = zero_lseek, 845 .read = read_zero, 846 .write = write_zero, 847 .mmap = mmap_zero, 848 }; 849 850 /* 851 * capabilities for /dev/zero 852 * - permits private mappings, "copies" are taken of the source of zeros 853 */ 854 static struct backing_dev_info zero_bdi = { 855 .capabilities = BDI_CAP_MAP_COPY, 856 }; 857 858 static const struct file_operations full_fops = { 859 .llseek = full_lseek, 860 .read = read_full, 861 .write = write_full, 862 }; 863 864 #ifdef CONFIG_CRASH_DUMP 865 static const struct file_operations oldmem_fops = { 866 .read = read_oldmem, 867 .open = open_oldmem, 868 }; 869 #endif 870 871 static ssize_t kmsg_write(struct file * file, const char __user * buf, 872 size_t count, loff_t *ppos) 873 { 874 char *tmp; 875 ssize_t ret; 876 877 tmp = kmalloc(count + 1, GFP_KERNEL); 878 if (tmp == NULL) 879 return -ENOMEM; 880 ret = -EFAULT; 881 if (!copy_from_user(tmp, buf, count)) { 882 tmp[count] = 0; 883 ret = printk("%s", tmp); 884 if (ret > count) 885 /* printk can add a prefix */ 886 ret = count; 887 } 888 kfree(tmp); 889 return ret; 890 } 891 892 static const struct file_operations kmsg_fops = { 893 .write = kmsg_write, 894 }; 895 896 static int memory_open(struct inode * inode, struct file * filp) 897 { 898 switch (iminor(inode)) { 899 case 1: 900 filp->f_op = &mem_fops; 901 filp->f_mapping->backing_dev_info = 902 &directly_mappable_cdev_bdi; 903 break; 904 case 2: 905 filp->f_op = &kmem_fops; 906 filp->f_mapping->backing_dev_info = 907 &directly_mappable_cdev_bdi; 908 break; 909 case 3: 910 filp->f_op = &null_fops; 911 break; 912 #if (defined(CONFIG_ISA) || defined(CONFIG_PCI)) && !defined(__mc68000__) 913 case 4: 914 filp->f_op = &port_fops; 915 break; 916 #endif 917 case 5: 918 filp->f_mapping->backing_dev_info = &zero_bdi; 919 filp->f_op = &zero_fops; 920 break; 921 case 7: 922 filp->f_op = &full_fops; 923 break; 924 case 8: 925 filp->f_op = &random_fops; 926 break; 927 case 9: 928 filp->f_op = &urandom_fops; 929 break; 930 case 11: 931 filp->f_op = &kmsg_fops; 932 break; 933 #ifdef CONFIG_CRASH_DUMP 934 case 12: 935 filp->f_op = &oldmem_fops; 936 break; 937 #endif 938 default: 939 return -ENXIO; 940 } 941 if (filp->f_op && filp->f_op->open) 942 return filp->f_op->open(inode,filp); 943 return 0; 944 } 945 946 static const struct file_operations memory_fops = { 947 .open = memory_open, /* just a selector for the real open */ 948 }; 949 950 static const struct { 951 unsigned int minor; 952 char *name; 953 umode_t mode; 954 const struct file_operations *fops; 955 } devlist[] = { /* list of minor devices */ 956 {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops}, 957 {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops}, 958 {3, "null", S_IRUGO | S_IWUGO, &null_fops}, 959 #if (defined(CONFIG_ISA) || defined(CONFIG_PCI)) && !defined(__mc68000__) 960 {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops}, 961 #endif 962 {5, "zero", S_IRUGO | S_IWUGO, &zero_fops}, 963 {7, "full", S_IRUGO | S_IWUGO, &full_fops}, 964 {8, "random", S_IRUGO | S_IWUSR, &random_fops}, 965 {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops}, 966 {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops}, 967 #ifdef CONFIG_CRASH_DUMP 968 {12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops}, 969 #endif 970 }; 971 972 static struct class *mem_class; 973 974 static int __init chr_dev_init(void) 975 { 976 int i; 977 978 if (register_chrdev(MEM_MAJOR,"mem",&memory_fops)) 979 printk("unable to get major %d for memory devs\n", MEM_MAJOR); 980 981 mem_class = class_create(THIS_MODULE, "mem"); 982 for (i = 0; i < ARRAY_SIZE(devlist); i++) 983 device_create(mem_class, NULL, 984 MKDEV(MEM_MAJOR, devlist[i].minor), 985 devlist[i].name); 986 987 return 0; 988 } 989 990 fs_initcall(chr_dev_init); 991