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 30 #include <asm/uaccess.h> 31 #include <asm/io.h> 32 33 #ifdef CONFIG_IA64 34 # include <linux/efi.h> 35 #endif 36 37 /* 38 * Architectures vary in how they handle caching for addresses 39 * outside of main memory. 40 * 41 */ 42 static inline int uncached_access(struct file *file, unsigned long addr) 43 { 44 #if defined(__i386__) 45 /* 46 * On the PPro and successors, the MTRRs are used to set 47 * memory types for physical addresses outside main memory, 48 * so blindly setting PCD or PWT on those pages is wrong. 49 * For Pentiums and earlier, the surround logic should disable 50 * caching for the high addresses through the KEN pin, but 51 * we maintain the tradition of paranoia in this code. 52 */ 53 if (file->f_flags & O_SYNC) 54 return 1; 55 return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) || 56 test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) || 57 test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) || 58 test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) ) 59 && addr >= __pa(high_memory); 60 #elif defined(__x86_64__) 61 /* 62 * This is broken because it can generate memory type aliases, 63 * which can cause cache corruptions 64 * But it is only available for root and we have to be bug-to-bug 65 * compatible with i386. 66 */ 67 if (file->f_flags & O_SYNC) 68 return 1; 69 /* same behaviour as i386. PAT always set to cached and MTRRs control the 70 caching behaviour. 71 Hopefully a full PAT implementation will fix that soon. */ 72 return 0; 73 #elif defined(CONFIG_IA64) 74 /* 75 * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases. 76 */ 77 return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); 78 #else 79 /* 80 * Accessing memory above the top the kernel knows about or through a file pointer 81 * that was marked O_SYNC will be done non-cached. 82 */ 83 if (file->f_flags & O_SYNC) 84 return 1; 85 return addr >= __pa(high_memory); 86 #endif 87 } 88 89 #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE 90 static inline int valid_phys_addr_range(unsigned long addr, size_t count) 91 { 92 if (addr + count > __pa(high_memory)) 93 return 0; 94 95 return 1; 96 } 97 98 static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) 99 { 100 return 1; 101 } 102 #endif 103 104 /* 105 * This funcion reads the *physical* memory. The f_pos points directly to the 106 * memory location. 107 */ 108 static ssize_t read_mem(struct file * file, char __user * buf, 109 size_t count, loff_t *ppos) 110 { 111 unsigned long p = *ppos; 112 ssize_t read, sz; 113 char *ptr; 114 115 if (!valid_phys_addr_range(p, count)) 116 return -EFAULT; 117 read = 0; 118 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 119 /* we don't have page 0 mapped on sparc and m68k.. */ 120 if (p < PAGE_SIZE) { 121 sz = PAGE_SIZE - p; 122 if (sz > count) 123 sz = count; 124 if (sz > 0) { 125 if (clear_user(buf, sz)) 126 return -EFAULT; 127 buf += sz; 128 p += sz; 129 count -= sz; 130 read += sz; 131 } 132 } 133 #endif 134 135 while (count > 0) { 136 /* 137 * Handle first page in case it's not aligned 138 */ 139 if (-p & (PAGE_SIZE - 1)) 140 sz = -p & (PAGE_SIZE - 1); 141 else 142 sz = PAGE_SIZE; 143 144 sz = min_t(unsigned long, sz, count); 145 146 /* 147 * On ia64 if a page has been mapped somewhere as 148 * uncached, then it must also be accessed uncached 149 * by the kernel or data corruption may occur 150 */ 151 ptr = xlate_dev_mem_ptr(p); 152 153 if (copy_to_user(buf, ptr, sz)) 154 return -EFAULT; 155 buf += sz; 156 p += sz; 157 count -= sz; 158 read += sz; 159 } 160 161 *ppos += read; 162 return read; 163 } 164 165 static ssize_t write_mem(struct file * file, const char __user * buf, 166 size_t count, loff_t *ppos) 167 { 168 unsigned long p = *ppos; 169 ssize_t written, sz; 170 unsigned long copied; 171 void *ptr; 172 173 if (!valid_phys_addr_range(p, count)) 174 return -EFAULT; 175 176 written = 0; 177 178 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 179 /* we don't have page 0 mapped on sparc and m68k.. */ 180 if (p < PAGE_SIZE) { 181 unsigned long sz = PAGE_SIZE - p; 182 if (sz > count) 183 sz = count; 184 /* Hmm. Do something? */ 185 buf += sz; 186 p += sz; 187 count -= sz; 188 written += sz; 189 } 190 #endif 191 192 while (count > 0) { 193 /* 194 * Handle first page in case it's not aligned 195 */ 196 if (-p & (PAGE_SIZE - 1)) 197 sz = -p & (PAGE_SIZE - 1); 198 else 199 sz = PAGE_SIZE; 200 201 sz = min_t(unsigned long, sz, count); 202 203 /* 204 * On ia64 if a page has been mapped somewhere as 205 * uncached, then it must also be accessed uncached 206 * by the kernel or data corruption may occur 207 */ 208 ptr = xlate_dev_mem_ptr(p); 209 210 copied = copy_from_user(ptr, buf, sz); 211 if (copied) { 212 written += sz - copied; 213 if (written) 214 break; 215 return -EFAULT; 216 } 217 buf += sz; 218 p += sz; 219 count -= sz; 220 written += sz; 221 } 222 223 *ppos += written; 224 return written; 225 } 226 227 #ifndef __HAVE_PHYS_MEM_ACCESS_PROT 228 static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 229 unsigned long size, pgprot_t vma_prot) 230 { 231 #ifdef pgprot_noncached 232 unsigned long offset = pfn << PAGE_SHIFT; 233 234 if (uncached_access(file, offset)) 235 return pgprot_noncached(vma_prot); 236 #endif 237 return vma_prot; 238 } 239 #endif 240 241 static int mmap_mem(struct file * file, struct vm_area_struct * vma) 242 { 243 size_t size = vma->vm_end - vma->vm_start; 244 245 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) 246 return -EINVAL; 247 248 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, 249 size, 250 vma->vm_page_prot); 251 252 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ 253 if (remap_pfn_range(vma, 254 vma->vm_start, 255 vma->vm_pgoff, 256 size, 257 vma->vm_page_prot)) 258 return -EAGAIN; 259 return 0; 260 } 261 262 static int mmap_kmem(struct file * file, struct vm_area_struct * vma) 263 { 264 unsigned long pfn; 265 266 /* Turn a kernel-virtual address into a physical page frame */ 267 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; 268 269 /* 270 * RED-PEN: on some architectures there is more mapped memory 271 * than available in mem_map which pfn_valid checks 272 * for. Perhaps should add a new macro here. 273 * 274 * RED-PEN: vmalloc is not supported right now. 275 */ 276 if (!pfn_valid(pfn)) 277 return -EIO; 278 279 vma->vm_pgoff = pfn; 280 return mmap_mem(file, vma); 281 } 282 283 #ifdef CONFIG_CRASH_DUMP 284 /* 285 * Read memory corresponding to the old kernel. 286 */ 287 static ssize_t read_oldmem(struct file *file, char __user *buf, 288 size_t count, loff_t *ppos) 289 { 290 unsigned long pfn, offset; 291 size_t read = 0, csize; 292 int rc = 0; 293 294 while (count) { 295 pfn = *ppos / PAGE_SIZE; 296 if (pfn > saved_max_pfn) 297 return read; 298 299 offset = (unsigned long)(*ppos % PAGE_SIZE); 300 if (count > PAGE_SIZE - offset) 301 csize = PAGE_SIZE - offset; 302 else 303 csize = count; 304 305 rc = copy_oldmem_page(pfn, buf, csize, offset, 1); 306 if (rc < 0) 307 return rc; 308 buf += csize; 309 *ppos += csize; 310 read += csize; 311 count -= csize; 312 } 313 return read; 314 } 315 #endif 316 317 extern long vread(char *buf, char *addr, unsigned long count); 318 extern long vwrite(char *buf, char *addr, unsigned long count); 319 320 /* 321 * This function reads the *virtual* memory as seen by the kernel. 322 */ 323 static ssize_t read_kmem(struct file *file, char __user *buf, 324 size_t count, loff_t *ppos) 325 { 326 unsigned long p = *ppos; 327 ssize_t low_count, read, sz; 328 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ 329 330 read = 0; 331 if (p < (unsigned long) high_memory) { 332 low_count = count; 333 if (count > (unsigned long) high_memory - p) 334 low_count = (unsigned long) high_memory - p; 335 336 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 337 /* we don't have page 0 mapped on sparc and m68k.. */ 338 if (p < PAGE_SIZE && low_count > 0) { 339 size_t tmp = PAGE_SIZE - p; 340 if (tmp > low_count) tmp = low_count; 341 if (clear_user(buf, tmp)) 342 return -EFAULT; 343 buf += tmp; 344 p += tmp; 345 read += tmp; 346 low_count -= tmp; 347 count -= tmp; 348 } 349 #endif 350 while (low_count > 0) { 351 /* 352 * Handle first page in case it's not aligned 353 */ 354 if (-p & (PAGE_SIZE - 1)) 355 sz = -p & (PAGE_SIZE - 1); 356 else 357 sz = PAGE_SIZE; 358 359 sz = min_t(unsigned long, sz, low_count); 360 361 /* 362 * On ia64 if a page has been mapped somewhere as 363 * uncached, then it must also be accessed uncached 364 * by the kernel or data corruption may occur 365 */ 366 kbuf = xlate_dev_kmem_ptr((char *)p); 367 368 if (copy_to_user(buf, kbuf, sz)) 369 return -EFAULT; 370 buf += sz; 371 p += sz; 372 read += sz; 373 low_count -= sz; 374 count -= sz; 375 } 376 } 377 378 if (count > 0) { 379 kbuf = (char *)__get_free_page(GFP_KERNEL); 380 if (!kbuf) 381 return -ENOMEM; 382 while (count > 0) { 383 int len = count; 384 385 if (len > PAGE_SIZE) 386 len = PAGE_SIZE; 387 len = vread(kbuf, (char *)p, len); 388 if (!len) 389 break; 390 if (copy_to_user(buf, kbuf, len)) { 391 free_page((unsigned long)kbuf); 392 return -EFAULT; 393 } 394 count -= len; 395 buf += len; 396 read += len; 397 p += len; 398 } 399 free_page((unsigned long)kbuf); 400 } 401 *ppos = p; 402 return read; 403 } 404 405 406 static inline ssize_t 407 do_write_kmem(void *p, unsigned long realp, const char __user * buf, 408 size_t count, loff_t *ppos) 409 { 410 ssize_t written, sz; 411 unsigned long copied; 412 413 written = 0; 414 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 415 /* we don't have page 0 mapped on sparc and m68k.. */ 416 if (realp < PAGE_SIZE) { 417 unsigned long sz = PAGE_SIZE - realp; 418 if (sz > count) 419 sz = count; 420 /* Hmm. Do something? */ 421 buf += sz; 422 p += sz; 423 realp += sz; 424 count -= sz; 425 written += sz; 426 } 427 #endif 428 429 while (count > 0) { 430 char *ptr; 431 /* 432 * Handle first page in case it's not aligned 433 */ 434 if (-realp & (PAGE_SIZE - 1)) 435 sz = -realp & (PAGE_SIZE - 1); 436 else 437 sz = PAGE_SIZE; 438 439 sz = min_t(unsigned long, sz, count); 440 441 /* 442 * On ia64 if a page has been mapped somewhere as 443 * uncached, then it must also be accessed uncached 444 * by the kernel or data corruption may occur 445 */ 446 ptr = xlate_dev_kmem_ptr(p); 447 448 copied = copy_from_user(ptr, buf, sz); 449 if (copied) { 450 written += sz - copied; 451 if (written) 452 break; 453 return -EFAULT; 454 } 455 buf += sz; 456 p += sz; 457 realp += sz; 458 count -= sz; 459 written += sz; 460 } 461 462 *ppos += written; 463 return written; 464 } 465 466 467 /* 468 * This function writes to the *virtual* memory as seen by the kernel. 469 */ 470 static ssize_t write_kmem(struct file * file, const char __user * buf, 471 size_t count, loff_t *ppos) 472 { 473 unsigned long p = *ppos; 474 ssize_t wrote = 0; 475 ssize_t virtr = 0; 476 ssize_t written; 477 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ 478 479 if (p < (unsigned long) high_memory) { 480 481 wrote = count; 482 if (count > (unsigned long) high_memory - p) 483 wrote = (unsigned long) high_memory - p; 484 485 written = do_write_kmem((void*)p, p, buf, wrote, ppos); 486 if (written != wrote) 487 return written; 488 wrote = written; 489 p += wrote; 490 buf += wrote; 491 count -= wrote; 492 } 493 494 if (count > 0) { 495 kbuf = (char *)__get_free_page(GFP_KERNEL); 496 if (!kbuf) 497 return wrote ? wrote : -ENOMEM; 498 while (count > 0) { 499 int len = count; 500 501 if (len > PAGE_SIZE) 502 len = PAGE_SIZE; 503 if (len) { 504 written = copy_from_user(kbuf, buf, len); 505 if (written) { 506 if (wrote + virtr) 507 break; 508 free_page((unsigned long)kbuf); 509 return -EFAULT; 510 } 511 } 512 len = vwrite(kbuf, (char *)p, len); 513 count -= len; 514 buf += len; 515 virtr += len; 516 p += len; 517 } 518 free_page((unsigned long)kbuf); 519 } 520 521 *ppos = p; 522 return virtr + wrote; 523 } 524 525 #if defined(CONFIG_ISA) || !defined(__mc68000__) 526 static ssize_t read_port(struct file * file, char __user * buf, 527 size_t count, loff_t *ppos) 528 { 529 unsigned long i = *ppos; 530 char __user *tmp = buf; 531 532 if (!access_ok(VERIFY_WRITE, buf, count)) 533 return -EFAULT; 534 while (count-- > 0 && i < 65536) { 535 if (__put_user(inb(i),tmp) < 0) 536 return -EFAULT; 537 i++; 538 tmp++; 539 } 540 *ppos = i; 541 return tmp-buf; 542 } 543 544 static ssize_t write_port(struct file * file, const char __user * buf, 545 size_t count, loff_t *ppos) 546 { 547 unsigned long i = *ppos; 548 const char __user * tmp = buf; 549 550 if (!access_ok(VERIFY_READ,buf,count)) 551 return -EFAULT; 552 while (count-- > 0 && i < 65536) { 553 char c; 554 if (__get_user(c, tmp)) { 555 if (tmp > buf) 556 break; 557 return -EFAULT; 558 } 559 outb(c,i); 560 i++; 561 tmp++; 562 } 563 *ppos = i; 564 return tmp-buf; 565 } 566 #endif 567 568 static ssize_t read_null(struct file * file, char __user * buf, 569 size_t count, loff_t *ppos) 570 { 571 return 0; 572 } 573 574 static ssize_t write_null(struct file * file, const char __user * buf, 575 size_t count, loff_t *ppos) 576 { 577 return count; 578 } 579 580 static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, 581 struct splice_desc *sd) 582 { 583 return sd->len; 584 } 585 586 static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out, 587 loff_t *ppos, size_t len, unsigned int flags) 588 { 589 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); 590 } 591 592 #ifdef CONFIG_MMU 593 /* 594 * For fun, we are using the MMU for this. 595 */ 596 static inline size_t read_zero_pagealigned(char __user * buf, size_t size) 597 { 598 struct mm_struct *mm; 599 struct vm_area_struct * vma; 600 unsigned long addr=(unsigned long)buf; 601 602 mm = current->mm; 603 /* Oops, this was forgotten before. -ben */ 604 down_read(&mm->mmap_sem); 605 606 /* For private mappings, just map in zero pages. */ 607 for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) { 608 unsigned long count; 609 610 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0) 611 goto out_up; 612 if (vma->vm_flags & (VM_SHARED | VM_HUGETLB)) 613 break; 614 count = vma->vm_end - addr; 615 if (count > size) 616 count = size; 617 618 zap_page_range(vma, addr, count, NULL); 619 zeromap_page_range(vma, addr, count, PAGE_COPY); 620 621 size -= count; 622 buf += count; 623 addr += count; 624 if (size == 0) 625 goto out_up; 626 } 627 628 up_read(&mm->mmap_sem); 629 630 /* The shared case is hard. Let's do the conventional zeroing. */ 631 do { 632 unsigned long unwritten = clear_user(buf, PAGE_SIZE); 633 if (unwritten) 634 return size + unwritten - PAGE_SIZE; 635 cond_resched(); 636 buf += PAGE_SIZE; 637 size -= PAGE_SIZE; 638 } while (size); 639 640 return size; 641 out_up: 642 up_read(&mm->mmap_sem); 643 return size; 644 } 645 646 static ssize_t read_zero(struct file * file, char __user * buf, 647 size_t count, loff_t *ppos) 648 { 649 unsigned long left, unwritten, written = 0; 650 651 if (!count) 652 return 0; 653 654 if (!access_ok(VERIFY_WRITE, buf, count)) 655 return -EFAULT; 656 657 left = count; 658 659 /* do we want to be clever? Arbitrary cut-off */ 660 if (count >= PAGE_SIZE*4) { 661 unsigned long partial; 662 663 /* How much left of the page? */ 664 partial = (PAGE_SIZE-1) & -(unsigned long) buf; 665 unwritten = clear_user(buf, partial); 666 written = partial - unwritten; 667 if (unwritten) 668 goto out; 669 left -= partial; 670 buf += partial; 671 unwritten = read_zero_pagealigned(buf, left & PAGE_MASK); 672 written += (left & PAGE_MASK) - unwritten; 673 if (unwritten) 674 goto out; 675 buf += left & PAGE_MASK; 676 left &= ~PAGE_MASK; 677 } 678 unwritten = clear_user(buf, left); 679 written += left - unwritten; 680 out: 681 return written ? written : -EFAULT; 682 } 683 684 static int mmap_zero(struct file * file, struct vm_area_struct * vma) 685 { 686 if (vma->vm_flags & VM_SHARED) 687 return shmem_zero_setup(vma); 688 if (zeromap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot)) 689 return -EAGAIN; 690 return 0; 691 } 692 #else /* CONFIG_MMU */ 693 static ssize_t read_zero(struct file * file, char * buf, 694 size_t count, loff_t *ppos) 695 { 696 size_t todo = count; 697 698 while (todo) { 699 size_t chunk = todo; 700 701 if (chunk > 4096) 702 chunk = 4096; /* Just for latency reasons */ 703 if (clear_user(buf, chunk)) 704 return -EFAULT; 705 buf += chunk; 706 todo -= chunk; 707 cond_resched(); 708 } 709 return count; 710 } 711 712 static int mmap_zero(struct file * file, struct vm_area_struct * vma) 713 { 714 return -ENOSYS; 715 } 716 #endif /* CONFIG_MMU */ 717 718 static ssize_t write_full(struct file * file, const char __user * buf, 719 size_t count, loff_t *ppos) 720 { 721 return -ENOSPC; 722 } 723 724 /* 725 * Special lseek() function for /dev/null and /dev/zero. Most notably, you 726 * can fopen() both devices with "a" now. This was previously impossible. 727 * -- SRB. 728 */ 729 730 static loff_t null_lseek(struct file * file, loff_t offset, int orig) 731 { 732 return file->f_pos = 0; 733 } 734 735 /* 736 * The memory devices use the full 32/64 bits of the offset, and so we cannot 737 * check against negative addresses: they are ok. The return value is weird, 738 * though, in that case (0). 739 * 740 * also note that seeking relative to the "end of file" isn't supported: 741 * it has no meaning, so it returns -EINVAL. 742 */ 743 static loff_t memory_lseek(struct file * file, loff_t offset, int orig) 744 { 745 loff_t ret; 746 747 mutex_lock(&file->f_dentry->d_inode->i_mutex); 748 switch (orig) { 749 case 0: 750 file->f_pos = offset; 751 ret = file->f_pos; 752 force_successful_syscall_return(); 753 break; 754 case 1: 755 file->f_pos += offset; 756 ret = file->f_pos; 757 force_successful_syscall_return(); 758 break; 759 default: 760 ret = -EINVAL; 761 } 762 mutex_unlock(&file->f_dentry->d_inode->i_mutex); 763 return ret; 764 } 765 766 static int open_port(struct inode * inode, struct file * filp) 767 { 768 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; 769 } 770 771 #define zero_lseek null_lseek 772 #define full_lseek null_lseek 773 #define write_zero write_null 774 #define read_full read_zero 775 #define open_mem open_port 776 #define open_kmem open_mem 777 #define open_oldmem open_mem 778 779 static const struct file_operations mem_fops = { 780 .llseek = memory_lseek, 781 .read = read_mem, 782 .write = write_mem, 783 .mmap = mmap_mem, 784 .open = open_mem, 785 }; 786 787 static const struct file_operations kmem_fops = { 788 .llseek = memory_lseek, 789 .read = read_kmem, 790 .write = write_kmem, 791 .mmap = mmap_kmem, 792 .open = open_kmem, 793 }; 794 795 static const struct file_operations null_fops = { 796 .llseek = null_lseek, 797 .read = read_null, 798 .write = write_null, 799 .splice_write = splice_write_null, 800 }; 801 802 #if defined(CONFIG_ISA) || !defined(__mc68000__) 803 static const struct file_operations port_fops = { 804 .llseek = memory_lseek, 805 .read = read_port, 806 .write = write_port, 807 .open = open_port, 808 }; 809 #endif 810 811 static const struct file_operations zero_fops = { 812 .llseek = zero_lseek, 813 .read = read_zero, 814 .write = write_zero, 815 .mmap = mmap_zero, 816 }; 817 818 static struct backing_dev_info zero_bdi = { 819 .capabilities = BDI_CAP_MAP_COPY, 820 }; 821 822 static const struct file_operations full_fops = { 823 .llseek = full_lseek, 824 .read = read_full, 825 .write = write_full, 826 }; 827 828 #ifdef CONFIG_CRASH_DUMP 829 static const struct file_operations oldmem_fops = { 830 .read = read_oldmem, 831 .open = open_oldmem, 832 }; 833 #endif 834 835 static ssize_t kmsg_write(struct file * file, const char __user * buf, 836 size_t count, loff_t *ppos) 837 { 838 char *tmp; 839 ssize_t ret; 840 841 tmp = kmalloc(count + 1, GFP_KERNEL); 842 if (tmp == NULL) 843 return -ENOMEM; 844 ret = -EFAULT; 845 if (!copy_from_user(tmp, buf, count)) { 846 tmp[count] = 0; 847 ret = printk("%s", tmp); 848 if (ret > count) 849 /* printk can add a prefix */ 850 ret = count; 851 } 852 kfree(tmp); 853 return ret; 854 } 855 856 static const struct file_operations kmsg_fops = { 857 .write = kmsg_write, 858 }; 859 860 static int memory_open(struct inode * inode, struct file * filp) 861 { 862 switch (iminor(inode)) { 863 case 1: 864 filp->f_op = &mem_fops; 865 break; 866 case 2: 867 filp->f_op = &kmem_fops; 868 break; 869 case 3: 870 filp->f_op = &null_fops; 871 break; 872 #if defined(CONFIG_ISA) || !defined(__mc68000__) 873 case 4: 874 filp->f_op = &port_fops; 875 break; 876 #endif 877 case 5: 878 filp->f_mapping->backing_dev_info = &zero_bdi; 879 filp->f_op = &zero_fops; 880 break; 881 case 7: 882 filp->f_op = &full_fops; 883 break; 884 case 8: 885 filp->f_op = &random_fops; 886 break; 887 case 9: 888 filp->f_op = &urandom_fops; 889 break; 890 case 11: 891 filp->f_op = &kmsg_fops; 892 break; 893 #ifdef CONFIG_CRASH_DUMP 894 case 12: 895 filp->f_op = &oldmem_fops; 896 break; 897 #endif 898 default: 899 return -ENXIO; 900 } 901 if (filp->f_op && filp->f_op->open) 902 return filp->f_op->open(inode,filp); 903 return 0; 904 } 905 906 static const struct file_operations memory_fops = { 907 .open = memory_open, /* just a selector for the real open */ 908 }; 909 910 static const struct { 911 unsigned int minor; 912 char *name; 913 umode_t mode; 914 const struct file_operations *fops; 915 } devlist[] = { /* list of minor devices */ 916 {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops}, 917 {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops}, 918 {3, "null", S_IRUGO | S_IWUGO, &null_fops}, 919 #if defined(CONFIG_ISA) || !defined(__mc68000__) 920 {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops}, 921 #endif 922 {5, "zero", S_IRUGO | S_IWUGO, &zero_fops}, 923 {7, "full", S_IRUGO | S_IWUGO, &full_fops}, 924 {8, "random", S_IRUGO | S_IWUSR, &random_fops}, 925 {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops}, 926 {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops}, 927 #ifdef CONFIG_CRASH_DUMP 928 {12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops}, 929 #endif 930 }; 931 932 static struct class *mem_class; 933 934 static int __init chr_dev_init(void) 935 { 936 int i; 937 938 if (register_chrdev(MEM_MAJOR,"mem",&memory_fops)) 939 printk("unable to get major %d for memory devs\n", MEM_MAJOR); 940 941 mem_class = class_create(THIS_MODULE, "mem"); 942 for (i = 0; i < ARRAY_SIZE(devlist); i++) 943 class_device_create(mem_class, NULL, 944 MKDEV(MEM_MAJOR, devlist[i].minor), 945 NULL, devlist[i].name); 946 947 return 0; 948 } 949 950 fs_initcall(chr_dev_init); 951