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/ptrace.h> 22#include <linux/device.h> 23#include <linux/highmem.h> 24#include <linux/crash_dump.h> 25#include <linux/backing-dev.h> 26#include <linux/bootmem.h> 27#include <linux/pipe_fs_i.h> 28#include <linux/pfn.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 */ 42static 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 90static 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 98static 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 */ 108static 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 165static 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 228static 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#ifndef CONFIG_MMU 242static unsigned long get_unmapped_area_mem(struct file *file, 243 unsigned long addr, 244 unsigned long len, 245 unsigned long pgoff, 246 unsigned long flags) 247{ 248 if (!valid_mmap_phys_addr_range(pgoff, len)) 249 return (unsigned long) -EINVAL; 250 return pgoff << PAGE_SHIFT; 251} 252 253/* can't do an in-place private mapping if there's no MMU */ 254static inline int private_mapping_ok(struct vm_area_struct *vma) 255{ 256 return vma->vm_flags & VM_MAYSHARE; 257} 258#else 259#define get_unmapped_area_mem NULL 260 261static inline int private_mapping_ok(struct vm_area_struct *vma) 262{ 263 return 1; 264} 265#endif 266 267static int mmap_mem(struct file * file, struct vm_area_struct * vma) 268{ 269 size_t size = vma->vm_end - vma->vm_start; 270 271 if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) 272 return -EINVAL; 273 274 if (!private_mapping_ok(vma)) 275 return -ENOSYS; 276 277 vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, 278 size, 279 vma->vm_page_prot); 280 281 /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ 282 if (remap_pfn_range(vma, 283 vma->vm_start, 284 vma->vm_pgoff, 285 size, 286 vma->vm_page_prot)) 287 return -EAGAIN; 288 return 0; 289} 290 291static int mmap_kmem(struct file * file, struct vm_area_struct * vma) 292{ 293 unsigned long pfn; 294 295 /* Turn a kernel-virtual address into a physical page frame */ 296 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; 297 298 /* 299 * RED-PEN: on some architectures there is more mapped memory 300 * than available in mem_map which pfn_valid checks 301 * for. Perhaps should add a new macro here. 302 * 303 * RED-PEN: vmalloc is not supported right now. 304 */ 305 if (!pfn_valid(pfn)) 306 return -EIO; 307 308 vma->vm_pgoff = pfn; 309 return mmap_mem(file, vma); 310} 311 312#ifdef CONFIG_CRASH_DUMP 313/* 314 * Read memory corresponding to the old kernel. 315 */ 316static ssize_t read_oldmem(struct file *file, char __user *buf, 317 size_t count, loff_t *ppos) 318{ 319 unsigned long pfn, offset; 320 size_t read = 0, csize; 321 int rc = 0; 322 323 while (count) { 324 pfn = *ppos / PAGE_SIZE; 325 if (pfn > saved_max_pfn) 326 return read; 327 328 offset = (unsigned long)(*ppos % PAGE_SIZE); 329 if (count > PAGE_SIZE - offset) 330 csize = PAGE_SIZE - offset; 331 else 332 csize = count; 333 334 rc = copy_oldmem_page(pfn, buf, csize, offset, 1); 335 if (rc < 0) 336 return rc; 337 buf += csize; 338 *ppos += csize; 339 read += csize; 340 count -= csize; 341 } 342 return read; 343} 344#endif 345 346extern long vread(char *buf, char *addr, unsigned long count); 347extern long vwrite(char *buf, char *addr, unsigned long count); 348 349/* 350 * This function reads the *virtual* memory as seen by the kernel. 351 */ 352static ssize_t read_kmem(struct file *file, char __user *buf, 353 size_t count, loff_t *ppos) 354{ 355 unsigned long p = *ppos; 356 ssize_t low_count, read, sz; 357 char * kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ 358 359 read = 0; 360 if (p < (unsigned long) high_memory) { 361 low_count = count; 362 if (count > (unsigned long) high_memory - p) 363 low_count = (unsigned long) high_memory - p; 364 365#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 366 /* we don't have page 0 mapped on sparc and m68k.. */ 367 if (p < PAGE_SIZE && low_count > 0) { 368 size_t tmp = PAGE_SIZE - p; 369 if (tmp > low_count) tmp = low_count; 370 if (clear_user(buf, tmp)) 371 return -EFAULT; 372 buf += tmp; 373 p += tmp; 374 read += tmp; 375 low_count -= tmp; 376 count -= tmp; 377 } 378#endif 379 while (low_count > 0) { 380 /* 381 * Handle first page in case it's not aligned 382 */ 383 if (-p & (PAGE_SIZE - 1)) 384 sz = -p & (PAGE_SIZE - 1); 385 else 386 sz = PAGE_SIZE; 387 388 sz = min_t(unsigned long, sz, low_count); 389 390 /* 391 * On ia64 if a page has been mapped somewhere as 392 * uncached, then it must also be accessed uncached 393 * by the kernel or data corruption may occur 394 */ 395 kbuf = xlate_dev_kmem_ptr((char *)p); 396 397 if (copy_to_user(buf, kbuf, sz)) 398 return -EFAULT; 399 buf += sz; 400 p += sz; 401 read += sz; 402 low_count -= sz; 403 count -= sz; 404 } 405 } 406 407 if (count > 0) { 408 kbuf = (char *)__get_free_page(GFP_KERNEL); 409 if (!kbuf) 410 return -ENOMEM; 411 while (count > 0) { 412 int len = count; 413 414 if (len > PAGE_SIZE) 415 len = PAGE_SIZE; 416 len = vread(kbuf, (char *)p, len); 417 if (!len) 418 break; 419 if (copy_to_user(buf, kbuf, len)) { 420 free_page((unsigned long)kbuf); 421 return -EFAULT; 422 } 423 count -= len; 424 buf += len; 425 read += len; 426 p += len; 427 } 428 free_page((unsigned long)kbuf); 429 } 430 *ppos = p; 431 return read; 432} 433 434 435static inline ssize_t 436do_write_kmem(void *p, unsigned long realp, const char __user * buf, 437 size_t count, loff_t *ppos) 438{ 439 ssize_t written, sz; 440 unsigned long copied; 441 442 written = 0; 443#ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED 444 /* we don't have page 0 mapped on sparc and m68k.. */ 445 if (realp < PAGE_SIZE) { 446 unsigned long sz = PAGE_SIZE - realp; 447 if (sz > count) 448 sz = count; 449 /* Hmm. Do something? */ 450 buf += sz; 451 p += sz; 452 realp += sz; 453 count -= sz; 454 written += sz; 455 } 456#endif 457 458 while (count > 0) { 459 char *ptr; 460 /* 461 * Handle first page in case it's not aligned 462 */ 463 if (-realp & (PAGE_SIZE - 1)) 464 sz = -realp & (PAGE_SIZE - 1); 465 else 466 sz = PAGE_SIZE; 467 468 sz = min_t(unsigned long, sz, count); 469 470 /* 471 * On ia64 if a page has been mapped somewhere as 472 * uncached, then it must also be accessed uncached 473 * by the kernel or data corruption may occur 474 */ 475 ptr = xlate_dev_kmem_ptr(p); 476 477 copied = copy_from_user(ptr, buf, sz); 478 if (copied) { 479 written += sz - copied; 480 if (written) 481 break; 482 return -EFAULT; 483 } 484 buf += sz; 485 p += sz; 486 realp += sz; 487 count -= sz; 488 written += sz; 489 } 490 491 *ppos += written; 492 return written; 493} 494 495 496/* 497 * This function writes to the *virtual* memory as seen by the kernel. 498 */ 499static ssize_t write_kmem(struct file * file, const char __user * buf, 500 size_t count, loff_t *ppos) 501{ 502 unsigned long p = *ppos; 503 ssize_t wrote = 0; 504 ssize_t virtr = 0; 505 ssize_t written; 506 char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ 507 508 if (p < (unsigned long) high_memory) { 509 510 wrote = count; 511 if (count > (unsigned long) high_memory - p) 512 wrote = (unsigned long) high_memory - p; 513 514 written = do_write_kmem((void*)p, p, buf, wrote, ppos); 515 if (written != wrote) 516 return written; 517 wrote = written; 518 p += wrote; 519 buf += wrote; 520 count -= wrote; 521 } 522 523 if (count > 0) { 524 kbuf = (char *)__get_free_page(GFP_KERNEL); 525 if (!kbuf) 526 return wrote ? wrote : -ENOMEM; 527 while (count > 0) { 528 int len = count; 529 530 if (len > PAGE_SIZE) 531 len = PAGE_SIZE; 532 if (len) { 533 written = copy_from_user(kbuf, buf, len); 534 if (written) { 535 if (wrote + virtr) 536 break; 537 free_page((unsigned long)kbuf); 538 return -EFAULT; 539 } 540 } 541 len = vwrite(kbuf, (char *)p, len); 542 count -= len; 543 buf += len; 544 virtr += len; 545 p += len; 546 } 547 free_page((unsigned long)kbuf); 548 } 549 550 *ppos = p; 551 return virtr + wrote; 552} 553 554#ifdef CONFIG_DEVPORT 555static ssize_t read_port(struct file * file, char __user * buf, 556 size_t count, loff_t *ppos) 557{ 558 unsigned long i = *ppos; 559 char __user *tmp = buf; 560 561 if (!access_ok(VERIFY_WRITE, buf, count)) 562 return -EFAULT; 563 while (count-- > 0 && i < 65536) { 564 if (__put_user(inb(i),tmp) < 0) 565 return -EFAULT; 566 i++; 567 tmp++; 568 } 569 *ppos = i; 570 return tmp-buf; 571} 572 573static ssize_t write_port(struct file * file, const char __user * buf, 574 size_t count, loff_t *ppos) 575{ 576 unsigned long i = *ppos; 577 const char __user * tmp = buf; 578 579 if (!access_ok(VERIFY_READ,buf,count)) 580 return -EFAULT; 581 while (count-- > 0 && i < 65536) { 582 char c; 583 if (__get_user(c, tmp)) { 584 if (tmp > buf) 585 break; 586 return -EFAULT; 587 } 588 outb(c,i); 589 i++; 590 tmp++; 591 } 592 *ppos = i; 593 return tmp-buf; 594} 595#endif 596 597static ssize_t read_null(struct file * file, char __user * buf, 598 size_t count, loff_t *ppos) 599{ 600 return 0; 601} 602 603static ssize_t write_null(struct file * file, const char __user * buf, 604 size_t count, loff_t *ppos) 605{ 606 return count; 607} 608 609static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, 610 struct splice_desc *sd) 611{ 612 return sd->len; 613} 614 615static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out, 616 loff_t *ppos, size_t len, unsigned int flags) 617{ 618 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); 619} 620 621#ifdef CONFIG_MMU 622/* 623 * For fun, we are using the MMU for this. 624 */ 625static inline size_t read_zero_pagealigned(char __user * buf, size_t size) 626{ 627 struct mm_struct *mm; 628 struct vm_area_struct * vma; 629 unsigned long addr=(unsigned long)buf; 630 631 mm = current->mm; 632 /* Oops, this was forgotten before. -ben */ 633 down_read(&mm->mmap_sem); 634 635 /* For private mappings, just map in zero pages. */ 636 for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) { 637 unsigned long count; 638 639 if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0) 640 goto out_up; 641 if (vma->vm_flags & (VM_SHARED | VM_HUGETLB)) 642 break; 643 count = vma->vm_end - addr; 644 if (count > size) 645 count = size; 646 647 zap_page_range(vma, addr, count, NULL); 648 if (zeromap_page_range(vma, addr, count, PAGE_COPY)) 649 break; 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; 671out_up: 672 up_read(&mm->mmap_sem); 673 return size; 674} 675 676static 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; 710out: 711 return written ? written : -EFAULT; 712} 713 714static int mmap_zero(struct file * file, struct vm_area_struct * vma) 715{ 716 int err; 717 718 if (vma->vm_flags & VM_SHARED) 719 return shmem_zero_setup(vma); 720 err = zeromap_page_range(vma, vma->vm_start, 721 vma->vm_end - vma->vm_start, vma->vm_page_prot); 722 BUG_ON(err == -EEXIST); 723 return err; 724} 725#else /* CONFIG_MMU */ 726static ssize_t read_zero(struct file * file, char * buf, 727 size_t count, loff_t *ppos) 728{ 729 size_t todo = count; 730 731 while (todo) { 732 size_t chunk = todo; 733 734 if (chunk > 4096) 735 chunk = 4096; /* Just for latency reasons */ 736 if (clear_user(buf, chunk)) 737 return -EFAULT; 738 buf += chunk; 739 todo -= chunk; 740 cond_resched(); 741 } 742 return count; 743} 744 745static int mmap_zero(struct file * file, struct vm_area_struct * vma) 746{ 747 return -ENOSYS; 748} 749#endif /* CONFIG_MMU */ 750 751static ssize_t write_full(struct file * file, const char __user * buf, 752 size_t count, loff_t *ppos) 753{ 754 return -ENOSPC; 755} 756 757/* 758 * Special lseek() function for /dev/null and /dev/zero. Most notably, you 759 * can fopen() both devices with "a" now. This was previously impossible. 760 * -- SRB. 761 */ 762 763static loff_t null_lseek(struct file * file, loff_t offset, int orig) 764{ 765 return file->f_pos = 0; 766} 767 768/* 769 * The memory devices use the full 32/64 bits of the offset, and so we cannot 770 * check against negative addresses: they are ok. The return value is weird, 771 * though, in that case (0). 772 * 773 * also note that seeking relative to the "end of file" isn't supported: 774 * it has no meaning, so it returns -EINVAL. 775 */ 776static loff_t memory_lseek(struct file * file, loff_t offset, int orig) 777{ 778 loff_t ret; 779 780 mutex_lock(&file->f_path.dentry->d_inode->i_mutex); 781 switch (orig) { 782 case 0: 783 file->f_pos = offset; 784 ret = file->f_pos; 785 force_successful_syscall_return(); 786 break; 787 case 1: 788 file->f_pos += offset; 789 ret = file->f_pos; 790 force_successful_syscall_return(); 791 break; 792 default: 793 ret = -EINVAL; 794 } 795 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); 796 return ret; 797} 798 799static int open_port(struct inode * inode, struct file * filp) 800{ 801 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; 802} 803 804#define zero_lseek null_lseek 805#define full_lseek null_lseek 806#define write_zero write_null 807#define read_full read_zero 808#define open_mem open_port 809#define open_kmem open_mem 810#define open_oldmem open_mem 811 812static const struct file_operations mem_fops = { 813 .llseek = memory_lseek, 814 .read = read_mem, 815 .write = write_mem, 816 .mmap = mmap_mem, 817 .open = open_mem, 818 .get_unmapped_area = get_unmapped_area_mem, 819}; 820 821static const struct file_operations kmem_fops = { 822 .llseek = memory_lseek, 823 .read = read_kmem, 824 .write = write_kmem, 825 .mmap = mmap_kmem, 826 .open = open_kmem, 827 .get_unmapped_area = get_unmapped_area_mem, 828}; 829 830static const struct file_operations null_fops = { 831 .llseek = null_lseek, 832 .read = read_null, 833 .write = write_null, 834 .splice_write = splice_write_null, 835}; 836 837#ifdef CONFIG_DEVPORT 838static const struct file_operations port_fops = { 839 .llseek = memory_lseek, 840 .read = read_port, 841 .write = write_port, 842 .open = open_port, 843}; 844#endif 845 846static const struct file_operations zero_fops = { 847 .llseek = zero_lseek, 848 .read = read_zero, 849 .write = write_zero, 850 .mmap = mmap_zero, 851}; 852 853/* 854 * capabilities for /dev/zero 855 * - permits private mappings, "copies" are taken of the source of zeros 856 */ 857static struct backing_dev_info zero_bdi = { 858 .capabilities = BDI_CAP_MAP_COPY, 859}; 860 861static const struct file_operations full_fops = { 862 .llseek = full_lseek, 863 .read = read_full, 864 .write = write_full, 865}; 866 867#ifdef CONFIG_CRASH_DUMP 868static const struct file_operations oldmem_fops = { 869 .read = read_oldmem, 870 .open = open_oldmem, 871}; 872#endif 873 874static ssize_t kmsg_write(struct file * file, const char __user * buf, 875 size_t count, loff_t *ppos) 876{ 877 char *tmp; 878 ssize_t ret; 879 880 tmp = kmalloc(count + 1, GFP_KERNEL); 881 if (tmp == NULL) 882 return -ENOMEM; 883 ret = -EFAULT; 884 if (!copy_from_user(tmp, buf, count)) { 885 tmp[count] = 0; 886 ret = printk("%s", tmp); 887 if (ret > count) 888 /* printk can add a prefix */ 889 ret = count; 890 } 891 kfree(tmp); 892 return ret; 893} 894 895static const struct file_operations kmsg_fops = { 896 .write = kmsg_write, 897}; 898 899static int memory_open(struct inode * inode, struct file * filp) 900{ 901 switch (iminor(inode)) { 902 case 1: 903 filp->f_op = &mem_fops; 904 filp->f_mapping->backing_dev_info = 905 &directly_mappable_cdev_bdi; 906 break; 907 case 2: 908 filp->f_op = &kmem_fops; 909 filp->f_mapping->backing_dev_info = 910 &directly_mappable_cdev_bdi; 911 break; 912 case 3: 913 filp->f_op = &null_fops; 914 break; 915#ifdef CONFIG_DEVPORT 916 case 4: 917 filp->f_op = &port_fops; 918 break; 919#endif 920 case 5: 921 filp->f_mapping->backing_dev_info = &zero_bdi; 922 filp->f_op = &zero_fops; 923 break; 924 case 7: 925 filp->f_op = &full_fops; 926 break; 927 case 8: 928 filp->f_op = &random_fops; 929 break; 930 case 9: 931 filp->f_op = &urandom_fops; 932 break; 933 case 11: 934 filp->f_op = &kmsg_fops; 935 break; 936#ifdef CONFIG_CRASH_DUMP 937 case 12: 938 filp->f_op = &oldmem_fops; 939 break; 940#endif 941 default: 942 return -ENXIO; 943 } 944 if (filp->f_op && filp->f_op->open) 945 return filp->f_op->open(inode,filp); 946 return 0; 947} 948 949static const struct file_operations memory_fops = { 950 .open = memory_open, /* just a selector for the real open */ 951}; 952 953static const struct { 954 unsigned int minor; 955 char *name; 956 umode_t mode; 957 const struct file_operations *fops; 958} devlist[] = { /* list of minor devices */ 959 {1, "mem", S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops}, 960 {2, "kmem", S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops}, 961 {3, "null", S_IRUGO | S_IWUGO, &null_fops}, 962#ifdef CONFIG_DEVPORT 963 {4, "port", S_IRUSR | S_IWUSR | S_IRGRP, &port_fops}, 964#endif 965 {5, "zero", S_IRUGO | S_IWUGO, &zero_fops}, 966 {7, "full", S_IRUGO | S_IWUGO, &full_fops}, 967 {8, "random", S_IRUGO | S_IWUSR, &random_fops}, 968 {9, "urandom", S_IRUGO | S_IWUSR, &urandom_fops}, 969 {11,"kmsg", S_IRUGO | S_IWUSR, &kmsg_fops}, 970#ifdef CONFIG_CRASH_DUMP 971 {12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops}, 972#endif 973}; 974 975static struct class *mem_class; 976 977static int __init chr_dev_init(void) 978{ 979 int i; 980 981 if (register_chrdev(MEM_MAJOR,"mem",&memory_fops)) 982 printk("unable to get major %d for memory devs\n", MEM_MAJOR); 983 984 mem_class = class_create(THIS_MODULE, "mem"); 985 for (i = 0; i < ARRAY_SIZE(devlist); i++) 986 device_create(mem_class, NULL, 987 MKDEV(MEM_MAJOR, devlist[i].minor), 988 devlist[i].name); 989 990 return 0; 991} 992 993fs_initcall(chr_dev_init); 994