| 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 mmapping 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/splice.h> |
| 28 | #include <linux/pfn.h> |
| 29 | #include <linux/export.h> |
| 30 | #include <linux/io.h> |
| 31 | #include <linux/aio.h> |
| 32 | |
| 33 | #include <asm/uaccess.h> |
| 34 | |
| 35 | #ifdef CONFIG_IA64 |
| 36 | # include <linux/efi.h> |
| 37 | #endif |
| 38 | |
| 39 | #define DEVPORT_MINOR 4 |
| 40 | |
| 41 | static inline unsigned long size_inside_page(unsigned long start, |
| 42 | unsigned long size) |
| 43 | { |
| 44 | unsigned long sz; |
| 45 | |
| 46 | sz = PAGE_SIZE - (start & (PAGE_SIZE - 1)); |
| 47 | |
| 48 | return min(sz, size); |
| 49 | } |
| 50 | |
| 51 | #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE |
| 52 | static inline int valid_phys_addr_range(phys_addr_t addr, size_t count) |
| 53 | { |
| 54 | return addr + count <= __pa(high_memory); |
| 55 | } |
| 56 | |
| 57 | static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) |
| 58 | { |
| 59 | return 1; |
| 60 | } |
| 61 | #endif |
| 62 | |
| 63 | #if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) |
| 64 | #ifdef CONFIG_STRICT_DEVMEM |
| 65 | static inline int page_is_allowed(unsigned long pfn) |
| 66 | { |
| 67 | return devmem_is_allowed(pfn); |
| 68 | } |
| 69 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
| 70 | { |
| 71 | u64 from = ((u64)pfn) << PAGE_SHIFT; |
| 72 | u64 to = from + size; |
| 73 | u64 cursor = from; |
| 74 | |
| 75 | while (cursor < to) { |
| 76 | if (!devmem_is_allowed(pfn)) |
| 77 | return 0; |
| 78 | cursor += PAGE_SIZE; |
| 79 | pfn++; |
| 80 | } |
| 81 | return 1; |
| 82 | } |
| 83 | #else |
| 84 | static inline int page_is_allowed(unsigned long pfn) |
| 85 | { |
| 86 | return 1; |
| 87 | } |
| 88 | static inline int range_is_allowed(unsigned long pfn, unsigned long size) |
| 89 | { |
| 90 | return 1; |
| 91 | } |
| 92 | #endif |
| 93 | #endif |
| 94 | |
| 95 | #ifdef CONFIG_DEVMEM |
| 96 | void __weak unxlate_dev_mem_ptr(unsigned long phys, void *addr) |
| 97 | { |
| 98 | } |
| 99 | |
| 100 | /* |
| 101 | * This funcion reads the *physical* memory. The f_pos points directly to the |
| 102 | * memory location. |
| 103 | */ |
| 104 | static ssize_t read_mem(struct file *file, char __user *buf, |
| 105 | size_t count, loff_t *ppos) |
| 106 | { |
| 107 | phys_addr_t p = *ppos; |
| 108 | ssize_t read, sz; |
| 109 | char *ptr; |
| 110 | |
| 111 | if (!valid_phys_addr_range(p, count)) |
| 112 | return -EFAULT; |
| 113 | read = 0; |
| 114 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
| 115 | /* we don't have page 0 mapped on sparc and m68k.. */ |
| 116 | if (p < PAGE_SIZE) { |
| 117 | sz = size_inside_page(p, count); |
| 118 | if (sz > 0) { |
| 119 | if (clear_user(buf, sz)) |
| 120 | return -EFAULT; |
| 121 | buf += sz; |
| 122 | p += sz; |
| 123 | count -= sz; |
| 124 | read += sz; |
| 125 | } |
| 126 | } |
| 127 | #endif |
| 128 | |
| 129 | while (count > 0) { |
| 130 | unsigned long remaining; |
| 131 | int allowed; |
| 132 | |
| 133 | sz = size_inside_page(p, count); |
| 134 | |
| 135 | allowed = page_is_allowed(p >> PAGE_SHIFT); |
| 136 | if (!allowed) |
| 137 | return -EPERM; |
| 138 | if (allowed == 2) { |
| 139 | /* Show zeros for restricted memory. */ |
| 140 | remaining = clear_user(buf, sz); |
| 141 | } else { |
| 142 | /* |
| 143 | * On ia64 if a page has been mapped somewhere as |
| 144 | * uncached, then it must also be accessed uncached |
| 145 | * by the kernel or data corruption may occur. |
| 146 | */ |
| 147 | ptr = xlate_dev_mem_ptr(p); |
| 148 | if (!ptr) |
| 149 | return -EFAULT; |
| 150 | |
| 151 | remaining = copy_to_user(buf, ptr, sz); |
| 152 | |
| 153 | unxlate_dev_mem_ptr(p, ptr); |
| 154 | } |
| 155 | |
| 156 | if (remaining) |
| 157 | return -EFAULT; |
| 158 | |
| 159 | buf += sz; |
| 160 | p += sz; |
| 161 | count -= sz; |
| 162 | read += sz; |
| 163 | } |
| 164 | |
| 165 | *ppos += read; |
| 166 | return read; |
| 167 | } |
| 168 | |
| 169 | static ssize_t write_mem(struct file *file, const char __user *buf, |
| 170 | size_t count, loff_t *ppos) |
| 171 | { |
| 172 | phys_addr_t p = *ppos; |
| 173 | ssize_t written, sz; |
| 174 | unsigned long copied; |
| 175 | void *ptr; |
| 176 | |
| 177 | if (!valid_phys_addr_range(p, count)) |
| 178 | return -EFAULT; |
| 179 | |
| 180 | written = 0; |
| 181 | |
| 182 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
| 183 | /* we don't have page 0 mapped on sparc and m68k.. */ |
| 184 | if (p < PAGE_SIZE) { |
| 185 | sz = size_inside_page(p, count); |
| 186 | /* Hmm. Do something? */ |
| 187 | buf += sz; |
| 188 | p += sz; |
| 189 | count -= sz; |
| 190 | written += sz; |
| 191 | } |
| 192 | #endif |
| 193 | |
| 194 | while (count > 0) { |
| 195 | int allowed; |
| 196 | |
| 197 | sz = size_inside_page(p, count); |
| 198 | |
| 199 | allowed = page_is_allowed(p >> PAGE_SHIFT); |
| 200 | if (!allowed) |
| 201 | return -EPERM; |
| 202 | |
| 203 | /* Skip actual writing when a page is marked as restricted. */ |
| 204 | if (allowed == 1) { |
| 205 | /* |
| 206 | * On ia64 if a page has been mapped somewhere as |
| 207 | * uncached, then it must also be accessed uncached |
| 208 | * by the kernel or data corruption may occur. |
| 209 | */ |
| 210 | ptr = xlate_dev_mem_ptr(p); |
| 211 | if (!ptr) { |
| 212 | if (written) |
| 213 | break; |
| 214 | return -EFAULT; |
| 215 | } |
| 216 | |
| 217 | copied = copy_from_user(ptr, buf, sz); |
| 218 | unxlate_dev_mem_ptr(p, ptr); |
| 219 | if (copied) { |
| 220 | written += sz - copied; |
| 221 | if (written) |
| 222 | break; |
| 223 | return -EFAULT; |
| 224 | } |
| 225 | } |
| 226 | |
| 227 | buf += sz; |
| 228 | p += sz; |
| 229 | count -= sz; |
| 230 | written += sz; |
| 231 | } |
| 232 | |
| 233 | *ppos += written; |
| 234 | return written; |
| 235 | } |
| 236 | #endif /* CONFIG_DEVMEM */ |
| 237 | |
| 238 | #if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) |
| 239 | |
| 240 | int __weak phys_mem_access_prot_allowed(struct file *file, |
| 241 | unsigned long pfn, unsigned long size, pgprot_t *vma_prot) |
| 242 | { |
| 243 | return 1; |
| 244 | } |
| 245 | |
| 246 | #ifndef __HAVE_PHYS_MEM_ACCESS_PROT |
| 247 | |
| 248 | /* |
| 249 | * Architectures vary in how they handle caching for addresses |
| 250 | * outside of main memory. |
| 251 | * |
| 252 | */ |
| 253 | #ifdef pgprot_noncached |
| 254 | static int uncached_access(struct file *file, phys_addr_t addr) |
| 255 | { |
| 256 | #if defined(CONFIG_IA64) |
| 257 | /* |
| 258 | * On ia64, we ignore O_DSYNC because we cannot tolerate memory |
| 259 | * attribute aliases. |
| 260 | */ |
| 261 | return !(efi_mem_attributes(addr) & EFI_MEMORY_WB); |
| 262 | #elif defined(CONFIG_MIPS) |
| 263 | { |
| 264 | extern int __uncached_access(struct file *file, |
| 265 | unsigned long addr); |
| 266 | |
| 267 | return __uncached_access(file, addr); |
| 268 | } |
| 269 | #else |
| 270 | /* |
| 271 | * Accessing memory above the top the kernel knows about or through a |
| 272 | * file pointer |
| 273 | * that was marked O_DSYNC will be done non-cached. |
| 274 | */ |
| 275 | if (file->f_flags & O_DSYNC) |
| 276 | return 1; |
| 277 | return addr >= __pa(high_memory); |
| 278 | #endif |
| 279 | } |
| 280 | #endif |
| 281 | |
| 282 | static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, |
| 283 | unsigned long size, pgprot_t vma_prot) |
| 284 | { |
| 285 | #ifdef pgprot_noncached |
| 286 | phys_addr_t offset = pfn << PAGE_SHIFT; |
| 287 | |
| 288 | if (uncached_access(file, offset)) |
| 289 | return pgprot_noncached(vma_prot); |
| 290 | #endif |
| 291 | return vma_prot; |
| 292 | } |
| 293 | #endif |
| 294 | |
| 295 | #ifndef CONFIG_MMU |
| 296 | static unsigned long get_unmapped_area_mem(struct file *file, |
| 297 | unsigned long addr, |
| 298 | unsigned long len, |
| 299 | unsigned long pgoff, |
| 300 | unsigned long flags) |
| 301 | { |
| 302 | if (!valid_mmap_phys_addr_range(pgoff, len)) |
| 303 | return (unsigned long) -EINVAL; |
| 304 | return pgoff << PAGE_SHIFT; |
| 305 | } |
| 306 | |
| 307 | /* can't do an in-place private mapping if there's no MMU */ |
| 308 | static inline int private_mapping_ok(struct vm_area_struct *vma) |
| 309 | { |
| 310 | return vma->vm_flags & VM_MAYSHARE; |
| 311 | } |
| 312 | #else |
| 313 | #define get_unmapped_area_mem NULL |
| 314 | |
| 315 | static inline int private_mapping_ok(struct vm_area_struct *vma) |
| 316 | { |
| 317 | return 1; |
| 318 | } |
| 319 | #endif |
| 320 | |
| 321 | static const struct vm_operations_struct mmap_mem_ops = { |
| 322 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
| 323 | .access = generic_access_phys |
| 324 | #endif |
| 325 | }; |
| 326 | |
| 327 | static int mmap_mem(struct file *file, struct vm_area_struct *vma) |
| 328 | { |
| 329 | size_t size = vma->vm_end - vma->vm_start; |
| 330 | |
| 331 | if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) |
| 332 | return -EINVAL; |
| 333 | |
| 334 | if (!private_mapping_ok(vma)) |
| 335 | return -ENOSYS; |
| 336 | |
| 337 | if (!range_is_allowed(vma->vm_pgoff, size)) |
| 338 | return -EPERM; |
| 339 | |
| 340 | if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, |
| 341 | &vma->vm_page_prot)) |
| 342 | return -EINVAL; |
| 343 | |
| 344 | vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, |
| 345 | size, |
| 346 | vma->vm_page_prot); |
| 347 | |
| 348 | vma->vm_ops = &mmap_mem_ops; |
| 349 | |
| 350 | /* Remap-pfn-range will mark the range VM_IO */ |
| 351 | if (remap_pfn_range(vma, |
| 352 | vma->vm_start, |
| 353 | vma->vm_pgoff, |
| 354 | size, |
| 355 | vma->vm_page_prot)) { |
| 356 | return -EAGAIN; |
| 357 | } |
| 358 | return 0; |
| 359 | } |
| 360 | #endif /* CONFIG_DEVMEM */ |
| 361 | |
| 362 | #ifdef CONFIG_DEVKMEM |
| 363 | static int mmap_kmem(struct file *file, struct vm_area_struct *vma) |
| 364 | { |
| 365 | unsigned long pfn; |
| 366 | |
| 367 | /* Turn a kernel-virtual address into a physical page frame */ |
| 368 | pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; |
| 369 | |
| 370 | /* |
| 371 | * RED-PEN: on some architectures there is more mapped memory than |
| 372 | * available in mem_map which pfn_valid checks for. Perhaps should add a |
| 373 | * new macro here. |
| 374 | * |
| 375 | * RED-PEN: vmalloc is not supported right now. |
| 376 | */ |
| 377 | if (!pfn_valid(pfn)) |
| 378 | return -EIO; |
| 379 | |
| 380 | vma->vm_pgoff = pfn; |
| 381 | return mmap_mem(file, vma); |
| 382 | } |
| 383 | #endif |
| 384 | |
| 385 | #ifdef CONFIG_CRASH_DUMP |
| 386 | /* |
| 387 | * Read memory corresponding to the old kernel. |
| 388 | */ |
| 389 | static ssize_t read_oldmem(struct file *file, char __user *buf, |
| 390 | size_t count, loff_t *ppos) |
| 391 | { |
| 392 | unsigned long pfn, offset; |
| 393 | size_t read = 0, csize; |
| 394 | int rc = 0; |
| 395 | |
| 396 | while (count) { |
| 397 | pfn = *ppos / PAGE_SIZE; |
| 398 | if (pfn > saved_max_pfn) |
| 399 | return read; |
| 400 | |
| 401 | offset = (unsigned long)(*ppos % PAGE_SIZE); |
| 402 | if (count > PAGE_SIZE - offset) |
| 403 | csize = PAGE_SIZE - offset; |
| 404 | else |
| 405 | csize = count; |
| 406 | |
| 407 | rc = copy_oldmem_page(pfn, buf, csize, offset, 1); |
| 408 | if (rc < 0) |
| 409 | return rc; |
| 410 | buf += csize; |
| 411 | *ppos += csize; |
| 412 | read += csize; |
| 413 | count -= csize; |
| 414 | } |
| 415 | return read; |
| 416 | } |
| 417 | #endif |
| 418 | |
| 419 | #ifdef CONFIG_DEVKMEM |
| 420 | /* |
| 421 | * This function reads the *virtual* memory as seen by the kernel. |
| 422 | */ |
| 423 | static ssize_t read_kmem(struct file *file, char __user *buf, |
| 424 | size_t count, loff_t *ppos) |
| 425 | { |
| 426 | unsigned long p = *ppos; |
| 427 | ssize_t low_count, read, sz; |
| 428 | char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */ |
| 429 | int err = 0; |
| 430 | |
| 431 | read = 0; |
| 432 | if (p < (unsigned long) high_memory) { |
| 433 | low_count = count; |
| 434 | if (count > (unsigned long)high_memory - p) |
| 435 | low_count = (unsigned long)high_memory - p; |
| 436 | |
| 437 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
| 438 | /* we don't have page 0 mapped on sparc and m68k.. */ |
| 439 | if (p < PAGE_SIZE && low_count > 0) { |
| 440 | sz = size_inside_page(p, low_count); |
| 441 | if (clear_user(buf, sz)) |
| 442 | return -EFAULT; |
| 443 | buf += sz; |
| 444 | p += sz; |
| 445 | read += sz; |
| 446 | low_count -= sz; |
| 447 | count -= sz; |
| 448 | } |
| 449 | #endif |
| 450 | while (low_count > 0) { |
| 451 | sz = size_inside_page(p, low_count); |
| 452 | |
| 453 | /* |
| 454 | * On ia64 if a page has been mapped somewhere as |
| 455 | * uncached, then it must also be accessed uncached |
| 456 | * by the kernel or data corruption may occur |
| 457 | */ |
| 458 | kbuf = xlate_dev_kmem_ptr((char *)p); |
| 459 | |
| 460 | if (copy_to_user(buf, kbuf, sz)) |
| 461 | return -EFAULT; |
| 462 | buf += sz; |
| 463 | p += sz; |
| 464 | read += sz; |
| 465 | low_count -= sz; |
| 466 | count -= sz; |
| 467 | } |
| 468 | } |
| 469 | |
| 470 | if (count > 0) { |
| 471 | kbuf = (char *)__get_free_page(GFP_KERNEL); |
| 472 | if (!kbuf) |
| 473 | return -ENOMEM; |
| 474 | while (count > 0) { |
| 475 | sz = size_inside_page(p, count); |
| 476 | if (!is_vmalloc_or_module_addr((void *)p)) { |
| 477 | err = -ENXIO; |
| 478 | break; |
| 479 | } |
| 480 | sz = vread(kbuf, (char *)p, sz); |
| 481 | if (!sz) |
| 482 | break; |
| 483 | if (copy_to_user(buf, kbuf, sz)) { |
| 484 | err = -EFAULT; |
| 485 | break; |
| 486 | } |
| 487 | count -= sz; |
| 488 | buf += sz; |
| 489 | read += sz; |
| 490 | p += sz; |
| 491 | } |
| 492 | free_page((unsigned long)kbuf); |
| 493 | } |
| 494 | *ppos = p; |
| 495 | return read ? read : err; |
| 496 | } |
| 497 | |
| 498 | |
| 499 | static ssize_t do_write_kmem(unsigned long p, const char __user *buf, |
| 500 | size_t count, loff_t *ppos) |
| 501 | { |
| 502 | ssize_t written, sz; |
| 503 | unsigned long copied; |
| 504 | |
| 505 | written = 0; |
| 506 | #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED |
| 507 | /* we don't have page 0 mapped on sparc and m68k.. */ |
| 508 | if (p < PAGE_SIZE) { |
| 509 | sz = size_inside_page(p, count); |
| 510 | /* Hmm. Do something? */ |
| 511 | buf += sz; |
| 512 | p += sz; |
| 513 | count -= sz; |
| 514 | written += sz; |
| 515 | } |
| 516 | #endif |
| 517 | |
| 518 | while (count > 0) { |
| 519 | char *ptr; |
| 520 | |
| 521 | sz = size_inside_page(p, count); |
| 522 | |
| 523 | /* |
| 524 | * On ia64 if a page has been mapped somewhere as uncached, then |
| 525 | * it must also be accessed uncached by the kernel or data |
| 526 | * corruption may occur. |
| 527 | */ |
| 528 | ptr = xlate_dev_kmem_ptr((char *)p); |
| 529 | |
| 530 | copied = copy_from_user(ptr, buf, sz); |
| 531 | if (copied) { |
| 532 | written += sz - copied; |
| 533 | if (written) |
| 534 | break; |
| 535 | return -EFAULT; |
| 536 | } |
| 537 | buf += sz; |
| 538 | p += sz; |
| 539 | count -= sz; |
| 540 | written += sz; |
| 541 | } |
| 542 | |
| 543 | *ppos += written; |
| 544 | return written; |
| 545 | } |
| 546 | |
| 547 | /* |
| 548 | * This function writes to the *virtual* memory as seen by the kernel. |
| 549 | */ |
| 550 | static ssize_t write_kmem(struct file *file, const char __user *buf, |
| 551 | size_t count, loff_t *ppos) |
| 552 | { |
| 553 | unsigned long p = *ppos; |
| 554 | ssize_t wrote = 0; |
| 555 | ssize_t virtr = 0; |
| 556 | char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ |
| 557 | int err = 0; |
| 558 | |
| 559 | if (p < (unsigned long) high_memory) { |
| 560 | unsigned long to_write = min_t(unsigned long, count, |
| 561 | (unsigned long)high_memory - p); |
| 562 | wrote = do_write_kmem(p, buf, to_write, ppos); |
| 563 | if (wrote != to_write) |
| 564 | return wrote; |
| 565 | p += wrote; |
| 566 | buf += wrote; |
| 567 | count -= wrote; |
| 568 | } |
| 569 | |
| 570 | if (count > 0) { |
| 571 | kbuf = (char *)__get_free_page(GFP_KERNEL); |
| 572 | if (!kbuf) |
| 573 | return wrote ? wrote : -ENOMEM; |
| 574 | while (count > 0) { |
| 575 | unsigned long sz = size_inside_page(p, count); |
| 576 | unsigned long n; |
| 577 | |
| 578 | if (!is_vmalloc_or_module_addr((void *)p)) { |
| 579 | err = -ENXIO; |
| 580 | break; |
| 581 | } |
| 582 | n = copy_from_user(kbuf, buf, sz); |
| 583 | if (n) { |
| 584 | err = -EFAULT; |
| 585 | break; |
| 586 | } |
| 587 | vwrite(kbuf, (char *)p, sz); |
| 588 | count -= sz; |
| 589 | buf += sz; |
| 590 | virtr += sz; |
| 591 | p += sz; |
| 592 | } |
| 593 | free_page((unsigned long)kbuf); |
| 594 | } |
| 595 | |
| 596 | *ppos = p; |
| 597 | return virtr + wrote ? : err; |
| 598 | } |
| 599 | #endif |
| 600 | |
| 601 | #ifdef CONFIG_DEVPORT |
| 602 | static ssize_t read_port(struct file *file, char __user *buf, |
| 603 | size_t count, loff_t *ppos) |
| 604 | { |
| 605 | unsigned long i = *ppos; |
| 606 | char __user *tmp = buf; |
| 607 | |
| 608 | if (!access_ok(VERIFY_WRITE, buf, count)) |
| 609 | return -EFAULT; |
| 610 | while (count-- > 0 && i < 65536) { |
| 611 | if (__put_user(inb(i), tmp) < 0) |
| 612 | return -EFAULT; |
| 613 | i++; |
| 614 | tmp++; |
| 615 | } |
| 616 | *ppos = i; |
| 617 | return tmp-buf; |
| 618 | } |
| 619 | |
| 620 | static ssize_t write_port(struct file *file, const char __user *buf, |
| 621 | size_t count, loff_t *ppos) |
| 622 | { |
| 623 | unsigned long i = *ppos; |
| 624 | const char __user *tmp = buf; |
| 625 | |
| 626 | if (!access_ok(VERIFY_READ, buf, count)) |
| 627 | return -EFAULT; |
| 628 | while (count-- > 0 && i < 65536) { |
| 629 | char c; |
| 630 | if (__get_user(c, tmp)) { |
| 631 | if (tmp > buf) |
| 632 | break; |
| 633 | return -EFAULT; |
| 634 | } |
| 635 | outb(c, i); |
| 636 | i++; |
| 637 | tmp++; |
| 638 | } |
| 639 | *ppos = i; |
| 640 | return tmp-buf; |
| 641 | } |
| 642 | #endif |
| 643 | |
| 644 | static ssize_t read_null(struct file *file, char __user *buf, |
| 645 | size_t count, loff_t *ppos) |
| 646 | { |
| 647 | return 0; |
| 648 | } |
| 649 | |
| 650 | static ssize_t write_null(struct file *file, const char __user *buf, |
| 651 | size_t count, loff_t *ppos) |
| 652 | { |
| 653 | return count; |
| 654 | } |
| 655 | |
| 656 | static ssize_t aio_read_null(struct kiocb *iocb, const struct iovec *iov, |
| 657 | unsigned long nr_segs, loff_t pos) |
| 658 | { |
| 659 | return 0; |
| 660 | } |
| 661 | |
| 662 | static ssize_t aio_write_null(struct kiocb *iocb, const struct iovec *iov, |
| 663 | unsigned long nr_segs, loff_t pos) |
| 664 | { |
| 665 | return iov_length(iov, nr_segs); |
| 666 | } |
| 667 | |
| 668 | static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf, |
| 669 | struct splice_desc *sd) |
| 670 | { |
| 671 | return sd->len; |
| 672 | } |
| 673 | |
| 674 | static ssize_t splice_write_null(struct pipe_inode_info *pipe, struct file *out, |
| 675 | loff_t *ppos, size_t len, unsigned int flags) |
| 676 | { |
| 677 | return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); |
| 678 | } |
| 679 | |
| 680 | static ssize_t read_zero(struct file *file, char __user *buf, |
| 681 | size_t count, loff_t *ppos) |
| 682 | { |
| 683 | size_t written; |
| 684 | |
| 685 | if (!count) |
| 686 | return 0; |
| 687 | |
| 688 | if (!access_ok(VERIFY_WRITE, buf, count)) |
| 689 | return -EFAULT; |
| 690 | |
| 691 | written = 0; |
| 692 | while (count) { |
| 693 | unsigned long unwritten; |
| 694 | size_t chunk = count; |
| 695 | |
| 696 | if (chunk > PAGE_SIZE) |
| 697 | chunk = PAGE_SIZE; /* Just for latency reasons */ |
| 698 | unwritten = __clear_user(buf, chunk); |
| 699 | written += chunk - unwritten; |
| 700 | if (unwritten) |
| 701 | break; |
| 702 | if (signal_pending(current)) |
| 703 | return written ? written : -ERESTARTSYS; |
| 704 | buf += chunk; |
| 705 | count -= chunk; |
| 706 | cond_resched(); |
| 707 | } |
| 708 | return written ? written : -EFAULT; |
| 709 | } |
| 710 | |
| 711 | static ssize_t aio_read_zero(struct kiocb *iocb, const struct iovec *iov, |
| 712 | unsigned long nr_segs, loff_t pos) |
| 713 | { |
| 714 | size_t written = 0; |
| 715 | unsigned long i; |
| 716 | ssize_t ret; |
| 717 | |
| 718 | for (i = 0; i < nr_segs; i++) { |
| 719 | ret = read_zero(iocb->ki_filp, iov[i].iov_base, iov[i].iov_len, |
| 720 | &pos); |
| 721 | if (ret < 0) |
| 722 | break; |
| 723 | written += ret; |
| 724 | } |
| 725 | |
| 726 | return written ? written : -EFAULT; |
| 727 | } |
| 728 | |
| 729 | static int mmap_zero(struct file *file, struct vm_area_struct *vma) |
| 730 | { |
| 731 | #ifndef CONFIG_MMU |
| 732 | return -ENOSYS; |
| 733 | #endif |
| 734 | if (vma->vm_flags & VM_SHARED) |
| 735 | return shmem_zero_setup(vma); |
| 736 | return 0; |
| 737 | } |
| 738 | |
| 739 | static ssize_t write_full(struct file *file, const char __user *buf, |
| 740 | size_t count, loff_t *ppos) |
| 741 | { |
| 742 | return -ENOSPC; |
| 743 | } |
| 744 | |
| 745 | /* |
| 746 | * Special lseek() function for /dev/null and /dev/zero. Most notably, you |
| 747 | * can fopen() both devices with "a" now. This was previously impossible. |
| 748 | * -- SRB. |
| 749 | */ |
| 750 | static loff_t null_lseek(struct file *file, loff_t offset, int orig) |
| 751 | { |
| 752 | return file->f_pos = 0; |
| 753 | } |
| 754 | |
| 755 | #if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) || defined(CONFIG_DEVPORT) |
| 756 | |
| 757 | /* |
| 758 | * The memory devices use the full 32/64 bits of the offset, and so we cannot |
| 759 | * check against negative addresses: they are ok. The return value is weird, |
| 760 | * though, in that case (0). |
| 761 | * |
| 762 | * also note that seeking relative to the "end of file" isn't supported: |
| 763 | * it has no meaning, so it returns -EINVAL. |
| 764 | */ |
| 765 | static loff_t memory_lseek(struct file *file, loff_t offset, int orig) |
| 766 | { |
| 767 | loff_t ret; |
| 768 | |
| 769 | mutex_lock(&file_inode(file)->i_mutex); |
| 770 | switch (orig) { |
| 771 | case SEEK_CUR: |
| 772 | offset += file->f_pos; |
| 773 | case SEEK_SET: |
| 774 | /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */ |
| 775 | if ((unsigned long long)offset >= ~0xFFFULL) { |
| 776 | ret = -EOVERFLOW; |
| 777 | break; |
| 778 | } |
| 779 | file->f_pos = offset; |
| 780 | ret = file->f_pos; |
| 781 | force_successful_syscall_return(); |
| 782 | break; |
| 783 | default: |
| 784 | ret = -EINVAL; |
| 785 | } |
| 786 | mutex_unlock(&file_inode(file)->i_mutex); |
| 787 | return ret; |
| 788 | } |
| 789 | |
| 790 | #endif |
| 791 | |
| 792 | #if defined(CONFIG_DEVMEM) || defined(CONFIG_DEVKMEM) || defined(CONFIG_DEVPORT) |
| 793 | static int open_port(struct inode *inode, struct file *filp) |
| 794 | { |
| 795 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; |
| 796 | } |
| 797 | #endif |
| 798 | |
| 799 | #define zero_lseek null_lseek |
| 800 | #define full_lseek null_lseek |
| 801 | #define write_zero write_null |
| 802 | #define read_full read_zero |
| 803 | #define aio_write_zero aio_write_null |
| 804 | #define open_mem open_port |
| 805 | #define open_kmem open_mem |
| 806 | #define open_oldmem open_mem |
| 807 | |
| 808 | #ifdef CONFIG_DEVMEM |
| 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 | #endif |
| 818 | |
| 819 | #ifdef CONFIG_DEVKMEM |
| 820 | static const struct file_operations kmem_fops = { |
| 821 | .llseek = memory_lseek, |
| 822 | .read = read_kmem, |
| 823 | .write = write_kmem, |
| 824 | .mmap = mmap_kmem, |
| 825 | .open = open_kmem, |
| 826 | .get_unmapped_area = get_unmapped_area_mem, |
| 827 | }; |
| 828 | #endif |
| 829 | |
| 830 | static const struct file_operations null_fops = { |
| 831 | .llseek = null_lseek, |
| 832 | .read = read_null, |
| 833 | .write = write_null, |
| 834 | .aio_read = aio_read_null, |
| 835 | .aio_write = aio_write_null, |
| 836 | .splice_write = splice_write_null, |
| 837 | }; |
| 838 | |
| 839 | #ifdef CONFIG_DEVPORT |
| 840 | static const struct file_operations port_fops = { |
| 841 | .llseek = memory_lseek, |
| 842 | .read = read_port, |
| 843 | .write = write_port, |
| 844 | .open = open_port, |
| 845 | }; |
| 846 | #endif |
| 847 | |
| 848 | static const struct file_operations zero_fops = { |
| 849 | .llseek = zero_lseek, |
| 850 | .read = read_zero, |
| 851 | .write = write_zero, |
| 852 | .aio_read = aio_read_zero, |
| 853 | .aio_write = aio_write_zero, |
| 854 | .mmap = mmap_zero, |
| 855 | }; |
| 856 | |
| 857 | /* |
| 858 | * capabilities for /dev/zero |
| 859 | * - permits private mappings, "copies" are taken of the source of zeros |
| 860 | * - no writeback happens |
| 861 | */ |
| 862 | static struct backing_dev_info zero_bdi = { |
| 863 | .name = "char/mem", |
| 864 | .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK, |
| 865 | }; |
| 866 | |
| 867 | static const struct file_operations full_fops = { |
| 868 | .llseek = full_lseek, |
| 869 | .read = read_full, |
| 870 | .write = write_full, |
| 871 | }; |
| 872 | |
| 873 | #ifdef CONFIG_CRASH_DUMP |
| 874 | static const struct file_operations oldmem_fops = { |
| 875 | .read = read_oldmem, |
| 876 | .open = open_oldmem, |
| 877 | .llseek = default_llseek, |
| 878 | }; |
| 879 | #endif |
| 880 | |
| 881 | static const struct memdev { |
| 882 | const char *name; |
| 883 | umode_t mode; |
| 884 | const struct file_operations *fops; |
| 885 | struct backing_dev_info *dev_info; |
| 886 | } devlist[] = { |
| 887 | #ifdef CONFIG_DEVMEM |
| 888 | [1] = { "mem", 0, &mem_fops, &directly_mappable_cdev_bdi }, |
| 889 | #endif |
| 890 | #ifdef CONFIG_DEVKMEM |
| 891 | [2] = { "kmem", 0, &kmem_fops, &directly_mappable_cdev_bdi }, |
| 892 | #endif |
| 893 | [3] = { "null", 0666, &null_fops, NULL }, |
| 894 | #ifdef CONFIG_DEVPORT |
| 895 | [4] = { "port", 0, &port_fops, NULL }, |
| 896 | #endif |
| 897 | [5] = { "zero", 0666, &zero_fops, &zero_bdi }, |
| 898 | [7] = { "full", 0666, &full_fops, NULL }, |
| 899 | [8] = { "random", 0666, &random_fops, NULL }, |
| 900 | [9] = { "urandom", 0666, &urandom_fops, NULL }, |
| 901 | #ifdef CONFIG_PRINTK |
| 902 | [11] = { "kmsg", 0644, &kmsg_fops, NULL }, |
| 903 | #endif |
| 904 | #ifdef CONFIG_CRASH_DUMP |
| 905 | [12] = { "oldmem", 0, &oldmem_fops, NULL }, |
| 906 | #endif |
| 907 | }; |
| 908 | |
| 909 | static int memory_open(struct inode *inode, struct file *filp) |
| 910 | { |
| 911 | int minor; |
| 912 | const struct memdev *dev; |
| 913 | |
| 914 | minor = iminor(inode); |
| 915 | if (minor >= ARRAY_SIZE(devlist)) |
| 916 | return -ENXIO; |
| 917 | |
| 918 | dev = &devlist[minor]; |
| 919 | if (!dev->fops) |
| 920 | return -ENXIO; |
| 921 | |
| 922 | filp->f_op = dev->fops; |
| 923 | if (dev->dev_info) |
| 924 | filp->f_mapping->backing_dev_info = dev->dev_info; |
| 925 | |
| 926 | /* Is /dev/mem or /dev/kmem ? */ |
| 927 | if (dev->dev_info == &directly_mappable_cdev_bdi) |
| 928 | filp->f_mode |= FMODE_UNSIGNED_OFFSET; |
| 929 | |
| 930 | if (dev->fops->open) |
| 931 | return dev->fops->open(inode, filp); |
| 932 | |
| 933 | return 0; |
| 934 | } |
| 935 | |
| 936 | static const struct file_operations memory_fops = { |
| 937 | .open = memory_open, |
| 938 | .llseek = noop_llseek, |
| 939 | }; |
| 940 | |
| 941 | static char *mem_devnode(struct device *dev, umode_t *mode) |
| 942 | { |
| 943 | if (mode && devlist[MINOR(dev->devt)].mode) |
| 944 | *mode = devlist[MINOR(dev->devt)].mode; |
| 945 | return NULL; |
| 946 | } |
| 947 | |
| 948 | static struct class *mem_class; |
| 949 | |
| 950 | static int __init chr_dev_init(void) |
| 951 | { |
| 952 | int minor; |
| 953 | int err; |
| 954 | |
| 955 | err = bdi_init(&zero_bdi); |
| 956 | if (err) |
| 957 | return err; |
| 958 | |
| 959 | if (register_chrdev(MEM_MAJOR, "mem", &memory_fops)) |
| 960 | printk("unable to get major %d for memory devs\n", MEM_MAJOR); |
| 961 | |
| 962 | mem_class = class_create(THIS_MODULE, "mem"); |
| 963 | if (IS_ERR(mem_class)) |
| 964 | return PTR_ERR(mem_class); |
| 965 | |
| 966 | mem_class->devnode = mem_devnode; |
| 967 | for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) { |
| 968 | if (!devlist[minor].name) |
| 969 | continue; |
| 970 | |
| 971 | /* |
| 972 | * Create /dev/port? |
| 973 | */ |
| 974 | if ((minor == DEVPORT_MINOR) && !arch_has_dev_port()) |
| 975 | continue; |
| 976 | |
| 977 | device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor), |
| 978 | NULL, devlist[minor].name); |
| 979 | } |
| 980 | |
| 981 | return tty_init(); |
| 982 | } |
| 983 | |
| 984 | fs_initcall(chr_dev_init); |