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