1 #include <linux/mm.h> 2 #include <linux/hugetlb.h> 3 #include <linux/mount.h> 4 #include <linux/seq_file.h> 5 #include <linux/highmem.h> 6 #include <linux/ptrace.h> 7 #include <linux/slab.h> 8 #include <linux/pagemap.h> 9 #include <linux/mempolicy.h> 10 #include <linux/swap.h> 11 #include <linux/swapops.h> 12 13 #include <asm/elf.h> 14 #include <asm/uaccess.h> 15 #include <asm/tlbflush.h> 16 #include "internal.h" 17 18 void task_mem(struct seq_file *m, struct mm_struct *mm) 19 { 20 unsigned long data, text, lib, swap; 21 unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss; 22 23 /* 24 * Note: to minimize their overhead, mm maintains hiwater_vm and 25 * hiwater_rss only when about to *lower* total_vm or rss. Any 26 * collector of these hiwater stats must therefore get total_vm 27 * and rss too, which will usually be the higher. Barriers? not 28 * worth the effort, such snapshots can always be inconsistent. 29 */ 30 hiwater_vm = total_vm = mm->total_vm; 31 if (hiwater_vm < mm->hiwater_vm) 32 hiwater_vm = mm->hiwater_vm; 33 hiwater_rss = total_rss = get_mm_rss(mm); 34 if (hiwater_rss < mm->hiwater_rss) 35 hiwater_rss = mm->hiwater_rss; 36 37 data = mm->total_vm - mm->shared_vm - mm->stack_vm; 38 text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10; 39 lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text; 40 swap = get_mm_counter(mm, MM_SWAPENTS); 41 seq_printf(m, 42 "VmPeak:\t%8lu kB\n" 43 "VmSize:\t%8lu kB\n" 44 "VmLck:\t%8lu kB\n" 45 "VmHWM:\t%8lu kB\n" 46 "VmRSS:\t%8lu kB\n" 47 "VmData:\t%8lu kB\n" 48 "VmStk:\t%8lu kB\n" 49 "VmExe:\t%8lu kB\n" 50 "VmLib:\t%8lu kB\n" 51 "VmPTE:\t%8lu kB\n" 52 "VmSwap:\t%8lu kB\n", 53 hiwater_vm << (PAGE_SHIFT-10), 54 (total_vm - mm->reserved_vm) << (PAGE_SHIFT-10), 55 mm->locked_vm << (PAGE_SHIFT-10), 56 hiwater_rss << (PAGE_SHIFT-10), 57 total_rss << (PAGE_SHIFT-10), 58 data << (PAGE_SHIFT-10), 59 mm->stack_vm << (PAGE_SHIFT-10), text, lib, 60 (PTRS_PER_PTE*sizeof(pte_t)*mm->nr_ptes) >> 10, 61 swap << (PAGE_SHIFT-10)); 62 } 63 64 unsigned long task_vsize(struct mm_struct *mm) 65 { 66 return PAGE_SIZE * mm->total_vm; 67 } 68 69 int task_statm(struct mm_struct *mm, int *shared, int *text, 70 int *data, int *resident) 71 { 72 *shared = get_mm_counter(mm, MM_FILEPAGES); 73 *text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) 74 >> PAGE_SHIFT; 75 *data = mm->total_vm - mm->shared_vm; 76 *resident = *shared + get_mm_counter(mm, MM_ANONPAGES); 77 return mm->total_vm; 78 } 79 80 static void pad_len_spaces(struct seq_file *m, int len) 81 { 82 len = 25 + sizeof(void*) * 6 - len; 83 if (len < 1) 84 len = 1; 85 seq_printf(m, "%*c", len, ' '); 86 } 87 88 static void vma_stop(struct proc_maps_private *priv, struct vm_area_struct *vma) 89 { 90 if (vma && vma != priv->tail_vma) { 91 struct mm_struct *mm = vma->vm_mm; 92 up_read(&mm->mmap_sem); 93 mmput(mm); 94 } 95 } 96 97 static void *m_start(struct seq_file *m, loff_t *pos) 98 { 99 struct proc_maps_private *priv = m->private; 100 unsigned long last_addr = m->version; 101 struct mm_struct *mm; 102 struct vm_area_struct *vma, *tail_vma = NULL; 103 loff_t l = *pos; 104 105 /* Clear the per syscall fields in priv */ 106 priv->task = NULL; 107 priv->tail_vma = NULL; 108 109 /* 110 * We remember last_addr rather than next_addr to hit with 111 * mmap_cache most of the time. We have zero last_addr at 112 * the beginning and also after lseek. We will have -1 last_addr 113 * after the end of the vmas. 114 */ 115 116 if (last_addr == -1UL) 117 return NULL; 118 119 priv->task = get_pid_task(priv->pid, PIDTYPE_PID); 120 if (!priv->task) 121 return NULL; 122 123 mm = mm_for_maps(priv->task); 124 if (!mm) 125 return NULL; 126 down_read(&mm->mmap_sem); 127 128 tail_vma = get_gate_vma(priv->task); 129 priv->tail_vma = tail_vma; 130 131 /* Start with last addr hint */ 132 vma = find_vma(mm, last_addr); 133 if (last_addr && vma) { 134 vma = vma->vm_next; 135 goto out; 136 } 137 138 /* 139 * Check the vma index is within the range and do 140 * sequential scan until m_index. 141 */ 142 vma = NULL; 143 if ((unsigned long)l < mm->map_count) { 144 vma = mm->mmap; 145 while (l-- && vma) 146 vma = vma->vm_next; 147 goto out; 148 } 149 150 if (l != mm->map_count) 151 tail_vma = NULL; /* After gate vma */ 152 153 out: 154 if (vma) 155 return vma; 156 157 /* End of vmas has been reached */ 158 m->version = (tail_vma != NULL)? 0: -1UL; 159 up_read(&mm->mmap_sem); 160 mmput(mm); 161 return tail_vma; 162 } 163 164 static void *m_next(struct seq_file *m, void *v, loff_t *pos) 165 { 166 struct proc_maps_private *priv = m->private; 167 struct vm_area_struct *vma = v; 168 struct vm_area_struct *tail_vma = priv->tail_vma; 169 170 (*pos)++; 171 if (vma && (vma != tail_vma) && vma->vm_next) 172 return vma->vm_next; 173 vma_stop(priv, vma); 174 return (vma != tail_vma)? tail_vma: NULL; 175 } 176 177 static void m_stop(struct seq_file *m, void *v) 178 { 179 struct proc_maps_private *priv = m->private; 180 struct vm_area_struct *vma = v; 181 182 vma_stop(priv, vma); 183 if (priv->task) 184 put_task_struct(priv->task); 185 } 186 187 static int do_maps_open(struct inode *inode, struct file *file, 188 const struct seq_operations *ops) 189 { 190 struct proc_maps_private *priv; 191 int ret = -ENOMEM; 192 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 193 if (priv) { 194 priv->pid = proc_pid(inode); 195 ret = seq_open(file, ops); 196 if (!ret) { 197 struct seq_file *m = file->private_data; 198 m->private = priv; 199 } else { 200 kfree(priv); 201 } 202 } 203 return ret; 204 } 205 206 static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma) 207 { 208 struct mm_struct *mm = vma->vm_mm; 209 struct file *file = vma->vm_file; 210 int flags = vma->vm_flags; 211 unsigned long ino = 0; 212 unsigned long long pgoff = 0; 213 unsigned long start; 214 dev_t dev = 0; 215 int len; 216 217 if (file) { 218 struct inode *inode = vma->vm_file->f_path.dentry->d_inode; 219 dev = inode->i_sb->s_dev; 220 ino = inode->i_ino; 221 pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT; 222 } 223 224 /* We don't show the stack guard page in /proc/maps */ 225 start = vma->vm_start; 226 if (vma->vm_flags & VM_GROWSDOWN) 227 if (!vma_stack_continue(vma->vm_prev, vma->vm_start)) 228 start += PAGE_SIZE; 229 230 seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n", 231 start, 232 vma->vm_end, 233 flags & VM_READ ? 'r' : '-', 234 flags & VM_WRITE ? 'w' : '-', 235 flags & VM_EXEC ? 'x' : '-', 236 flags & VM_MAYSHARE ? 's' : 'p', 237 pgoff, 238 MAJOR(dev), MINOR(dev), ino, &len); 239 240 /* 241 * Print the dentry name for named mappings, and a 242 * special [heap] marker for the heap: 243 */ 244 if (file) { 245 pad_len_spaces(m, len); 246 seq_path(m, &file->f_path, "\n"); 247 } else { 248 const char *name = arch_vma_name(vma); 249 if (!name) { 250 if (mm) { 251 if (vma->vm_start <= mm->start_brk && 252 vma->vm_end >= mm->brk) { 253 name = "[heap]"; 254 } else if (vma->vm_start <= mm->start_stack && 255 vma->vm_end >= mm->start_stack) { 256 name = "[stack]"; 257 } 258 } else { 259 name = "[vdso]"; 260 } 261 } 262 if (name) { 263 pad_len_spaces(m, len); 264 seq_puts(m, name); 265 } 266 } 267 seq_putc(m, '\n'); 268 } 269 270 static int show_map(struct seq_file *m, void *v) 271 { 272 struct vm_area_struct *vma = v; 273 struct proc_maps_private *priv = m->private; 274 struct task_struct *task = priv->task; 275 276 show_map_vma(m, vma); 277 278 if (m->count < m->size) /* vma is copied successfully */ 279 m->version = (vma != get_gate_vma(task))? vma->vm_start: 0; 280 return 0; 281 } 282 283 static const struct seq_operations proc_pid_maps_op = { 284 .start = m_start, 285 .next = m_next, 286 .stop = m_stop, 287 .show = show_map 288 }; 289 290 static int maps_open(struct inode *inode, struct file *file) 291 { 292 return do_maps_open(inode, file, &proc_pid_maps_op); 293 } 294 295 const struct file_operations proc_maps_operations = { 296 .open = maps_open, 297 .read = seq_read, 298 .llseek = seq_lseek, 299 .release = seq_release_private, 300 }; 301 302 /* 303 * Proportional Set Size(PSS): my share of RSS. 304 * 305 * PSS of a process is the count of pages it has in memory, where each 306 * page is divided by the number of processes sharing it. So if a 307 * process has 1000 pages all to itself, and 1000 shared with one other 308 * process, its PSS will be 1500. 309 * 310 * To keep (accumulated) division errors low, we adopt a 64bit 311 * fixed-point pss counter to minimize division errors. So (pss >> 312 * PSS_SHIFT) would be the real byte count. 313 * 314 * A shift of 12 before division means (assuming 4K page size): 315 * - 1M 3-user-pages add up to 8KB errors; 316 * - supports mapcount up to 2^24, or 16M; 317 * - supports PSS up to 2^52 bytes, or 4PB. 318 */ 319 #define PSS_SHIFT 12 320 321 #ifdef CONFIG_PROC_PAGE_MONITOR 322 struct mem_size_stats { 323 struct vm_area_struct *vma; 324 unsigned long resident; 325 unsigned long shared_clean; 326 unsigned long shared_dirty; 327 unsigned long private_clean; 328 unsigned long private_dirty; 329 unsigned long referenced; 330 unsigned long anonymous; 331 unsigned long swap; 332 u64 pss; 333 }; 334 335 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, 336 struct mm_walk *walk) 337 { 338 struct mem_size_stats *mss = walk->private; 339 struct vm_area_struct *vma = mss->vma; 340 pte_t *pte, ptent; 341 spinlock_t *ptl; 342 struct page *page; 343 int mapcount; 344 345 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 346 for (; addr != end; pte++, addr += PAGE_SIZE) { 347 ptent = *pte; 348 349 if (is_swap_pte(ptent)) { 350 mss->swap += PAGE_SIZE; 351 continue; 352 } 353 354 if (!pte_present(ptent)) 355 continue; 356 357 page = vm_normal_page(vma, addr, ptent); 358 if (!page) 359 continue; 360 361 if (PageAnon(page)) 362 mss->anonymous += PAGE_SIZE; 363 364 mss->resident += PAGE_SIZE; 365 /* Accumulate the size in pages that have been accessed. */ 366 if (pte_young(ptent) || PageReferenced(page)) 367 mss->referenced += PAGE_SIZE; 368 mapcount = page_mapcount(page); 369 if (mapcount >= 2) { 370 if (pte_dirty(ptent) || PageDirty(page)) 371 mss->shared_dirty += PAGE_SIZE; 372 else 373 mss->shared_clean += PAGE_SIZE; 374 mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount; 375 } else { 376 if (pte_dirty(ptent) || PageDirty(page)) 377 mss->private_dirty += PAGE_SIZE; 378 else 379 mss->private_clean += PAGE_SIZE; 380 mss->pss += (PAGE_SIZE << PSS_SHIFT); 381 } 382 } 383 pte_unmap_unlock(pte - 1, ptl); 384 cond_resched(); 385 return 0; 386 } 387 388 static int show_smap(struct seq_file *m, void *v) 389 { 390 struct proc_maps_private *priv = m->private; 391 struct task_struct *task = priv->task; 392 struct vm_area_struct *vma = v; 393 struct mem_size_stats mss; 394 struct mm_walk smaps_walk = { 395 .pmd_entry = smaps_pte_range, 396 .mm = vma->vm_mm, 397 .private = &mss, 398 }; 399 400 memset(&mss, 0, sizeof mss); 401 mss.vma = vma; 402 /* mmap_sem is held in m_start */ 403 if (vma->vm_mm && !is_vm_hugetlb_page(vma)) 404 walk_page_range(vma->vm_start, vma->vm_end, &smaps_walk); 405 406 show_map_vma(m, vma); 407 408 seq_printf(m, 409 "Size: %8lu kB\n" 410 "Rss: %8lu kB\n" 411 "Pss: %8lu kB\n" 412 "Shared_Clean: %8lu kB\n" 413 "Shared_Dirty: %8lu kB\n" 414 "Private_Clean: %8lu kB\n" 415 "Private_Dirty: %8lu kB\n" 416 "Referenced: %8lu kB\n" 417 "Anonymous: %8lu kB\n" 418 "Swap: %8lu kB\n" 419 "KernelPageSize: %8lu kB\n" 420 "MMUPageSize: %8lu kB\n", 421 (vma->vm_end - vma->vm_start) >> 10, 422 mss.resident >> 10, 423 (unsigned long)(mss.pss >> (10 + PSS_SHIFT)), 424 mss.shared_clean >> 10, 425 mss.shared_dirty >> 10, 426 mss.private_clean >> 10, 427 mss.private_dirty >> 10, 428 mss.referenced >> 10, 429 mss.anonymous >> 10, 430 mss.swap >> 10, 431 vma_kernel_pagesize(vma) >> 10, 432 vma_mmu_pagesize(vma) >> 10); 433 434 if (m->count < m->size) /* vma is copied successfully */ 435 m->version = (vma != get_gate_vma(task)) ? vma->vm_start : 0; 436 return 0; 437 } 438 439 static const struct seq_operations proc_pid_smaps_op = { 440 .start = m_start, 441 .next = m_next, 442 .stop = m_stop, 443 .show = show_smap 444 }; 445 446 static int smaps_open(struct inode *inode, struct file *file) 447 { 448 return do_maps_open(inode, file, &proc_pid_smaps_op); 449 } 450 451 const struct file_operations proc_smaps_operations = { 452 .open = smaps_open, 453 .read = seq_read, 454 .llseek = seq_lseek, 455 .release = seq_release_private, 456 }; 457 458 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr, 459 unsigned long end, struct mm_walk *walk) 460 { 461 struct vm_area_struct *vma = walk->private; 462 pte_t *pte, ptent; 463 spinlock_t *ptl; 464 struct page *page; 465 466 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 467 for (; addr != end; pte++, addr += PAGE_SIZE) { 468 ptent = *pte; 469 if (!pte_present(ptent)) 470 continue; 471 472 page = vm_normal_page(vma, addr, ptent); 473 if (!page) 474 continue; 475 476 /* Clear accessed and referenced bits. */ 477 ptep_test_and_clear_young(vma, addr, pte); 478 ClearPageReferenced(page); 479 } 480 pte_unmap_unlock(pte - 1, ptl); 481 cond_resched(); 482 return 0; 483 } 484 485 #define CLEAR_REFS_ALL 1 486 #define CLEAR_REFS_ANON 2 487 #define CLEAR_REFS_MAPPED 3 488 489 static ssize_t clear_refs_write(struct file *file, const char __user *buf, 490 size_t count, loff_t *ppos) 491 { 492 struct task_struct *task; 493 char buffer[PROC_NUMBUF]; 494 struct mm_struct *mm; 495 struct vm_area_struct *vma; 496 long type; 497 498 memset(buffer, 0, sizeof(buffer)); 499 if (count > sizeof(buffer) - 1) 500 count = sizeof(buffer) - 1; 501 if (copy_from_user(buffer, buf, count)) 502 return -EFAULT; 503 if (strict_strtol(strstrip(buffer), 10, &type)) 504 return -EINVAL; 505 if (type < CLEAR_REFS_ALL || type > CLEAR_REFS_MAPPED) 506 return -EINVAL; 507 task = get_proc_task(file->f_path.dentry->d_inode); 508 if (!task) 509 return -ESRCH; 510 mm = get_task_mm(task); 511 if (mm) { 512 struct mm_walk clear_refs_walk = { 513 .pmd_entry = clear_refs_pte_range, 514 .mm = mm, 515 }; 516 down_read(&mm->mmap_sem); 517 for (vma = mm->mmap; vma; vma = vma->vm_next) { 518 clear_refs_walk.private = vma; 519 if (is_vm_hugetlb_page(vma)) 520 continue; 521 /* 522 * Writing 1 to /proc/pid/clear_refs affects all pages. 523 * 524 * Writing 2 to /proc/pid/clear_refs only affects 525 * Anonymous pages. 526 * 527 * Writing 3 to /proc/pid/clear_refs only affects file 528 * mapped pages. 529 */ 530 if (type == CLEAR_REFS_ANON && vma->vm_file) 531 continue; 532 if (type == CLEAR_REFS_MAPPED && !vma->vm_file) 533 continue; 534 walk_page_range(vma->vm_start, vma->vm_end, 535 &clear_refs_walk); 536 } 537 flush_tlb_mm(mm); 538 up_read(&mm->mmap_sem); 539 mmput(mm); 540 } 541 put_task_struct(task); 542 543 return count; 544 } 545 546 const struct file_operations proc_clear_refs_operations = { 547 .write = clear_refs_write, 548 .llseek = noop_llseek, 549 }; 550 551 struct pagemapread { 552 int pos, len; 553 u64 *buffer; 554 }; 555 556 #define PM_ENTRY_BYTES sizeof(u64) 557 #define PM_STATUS_BITS 3 558 #define PM_STATUS_OFFSET (64 - PM_STATUS_BITS) 559 #define PM_STATUS_MASK (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET) 560 #define PM_STATUS(nr) (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK) 561 #define PM_PSHIFT_BITS 6 562 #define PM_PSHIFT_OFFSET (PM_STATUS_OFFSET - PM_PSHIFT_BITS) 563 #define PM_PSHIFT_MASK (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET) 564 #define PM_PSHIFT(x) (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK) 565 #define PM_PFRAME_MASK ((1LL << PM_PSHIFT_OFFSET) - 1) 566 #define PM_PFRAME(x) ((x) & PM_PFRAME_MASK) 567 568 #define PM_PRESENT PM_STATUS(4LL) 569 #define PM_SWAP PM_STATUS(2LL) 570 #define PM_NOT_PRESENT PM_PSHIFT(PAGE_SHIFT) 571 #define PM_END_OF_BUFFER 1 572 573 static int add_to_pagemap(unsigned long addr, u64 pfn, 574 struct pagemapread *pm) 575 { 576 pm->buffer[pm->pos++] = pfn; 577 if (pm->pos >= pm->len) 578 return PM_END_OF_BUFFER; 579 return 0; 580 } 581 582 static int pagemap_pte_hole(unsigned long start, unsigned long end, 583 struct mm_walk *walk) 584 { 585 struct pagemapread *pm = walk->private; 586 unsigned long addr; 587 int err = 0; 588 for (addr = start; addr < end; addr += PAGE_SIZE) { 589 err = add_to_pagemap(addr, PM_NOT_PRESENT, pm); 590 if (err) 591 break; 592 } 593 return err; 594 } 595 596 static u64 swap_pte_to_pagemap_entry(pte_t pte) 597 { 598 swp_entry_t e = pte_to_swp_entry(pte); 599 return swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT); 600 } 601 602 static u64 pte_to_pagemap_entry(pte_t pte) 603 { 604 u64 pme = 0; 605 if (is_swap_pte(pte)) 606 pme = PM_PFRAME(swap_pte_to_pagemap_entry(pte)) 607 | PM_PSHIFT(PAGE_SHIFT) | PM_SWAP; 608 else if (pte_present(pte)) 609 pme = PM_PFRAME(pte_pfn(pte)) 610 | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT; 611 return pme; 612 } 613 614 static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, 615 struct mm_walk *walk) 616 { 617 struct vm_area_struct *vma; 618 struct pagemapread *pm = walk->private; 619 pte_t *pte; 620 int err = 0; 621 622 /* find the first VMA at or above 'addr' */ 623 vma = find_vma(walk->mm, addr); 624 for (; addr != end; addr += PAGE_SIZE) { 625 u64 pfn = PM_NOT_PRESENT; 626 627 /* check to see if we've left 'vma' behind 628 * and need a new, higher one */ 629 if (vma && (addr >= vma->vm_end)) 630 vma = find_vma(walk->mm, addr); 631 632 /* check that 'vma' actually covers this address, 633 * and that it isn't a huge page vma */ 634 if (vma && (vma->vm_start <= addr) && 635 !is_vm_hugetlb_page(vma)) { 636 pte = pte_offset_map(pmd, addr); 637 pfn = pte_to_pagemap_entry(*pte); 638 /* unmap before userspace copy */ 639 pte_unmap(pte); 640 } 641 err = add_to_pagemap(addr, pfn, pm); 642 if (err) 643 return err; 644 } 645 646 cond_resched(); 647 648 return err; 649 } 650 651 #ifdef CONFIG_HUGETLB_PAGE 652 static u64 huge_pte_to_pagemap_entry(pte_t pte, int offset) 653 { 654 u64 pme = 0; 655 if (pte_present(pte)) 656 pme = PM_PFRAME(pte_pfn(pte) + offset) 657 | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT; 658 return pme; 659 } 660 661 /* This function walks within one hugetlb entry in the single call */ 662 static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask, 663 unsigned long addr, unsigned long end, 664 struct mm_walk *walk) 665 { 666 struct pagemapread *pm = walk->private; 667 int err = 0; 668 u64 pfn; 669 670 for (; addr != end; addr += PAGE_SIZE) { 671 int offset = (addr & ~hmask) >> PAGE_SHIFT; 672 pfn = huge_pte_to_pagemap_entry(*pte, offset); 673 err = add_to_pagemap(addr, pfn, pm); 674 if (err) 675 return err; 676 } 677 678 cond_resched(); 679 680 return err; 681 } 682 #endif /* HUGETLB_PAGE */ 683 684 /* 685 * /proc/pid/pagemap - an array mapping virtual pages to pfns 686 * 687 * For each page in the address space, this file contains one 64-bit entry 688 * consisting of the following: 689 * 690 * Bits 0-55 page frame number (PFN) if present 691 * Bits 0-4 swap type if swapped 692 * Bits 5-55 swap offset if swapped 693 * Bits 55-60 page shift (page size = 1<<page shift) 694 * Bit 61 reserved for future use 695 * Bit 62 page swapped 696 * Bit 63 page present 697 * 698 * If the page is not present but in swap, then the PFN contains an 699 * encoding of the swap file number and the page's offset into the 700 * swap. Unmapped pages return a null PFN. This allows determining 701 * precisely which pages are mapped (or in swap) and comparing mapped 702 * pages between processes. 703 * 704 * Efficient users of this interface will use /proc/pid/maps to 705 * determine which areas of memory are actually mapped and llseek to 706 * skip over unmapped regions. 707 */ 708 #define PAGEMAP_WALK_SIZE (PMD_SIZE) 709 #define PAGEMAP_WALK_MASK (PMD_MASK) 710 static ssize_t pagemap_read(struct file *file, char __user *buf, 711 size_t count, loff_t *ppos) 712 { 713 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode); 714 struct mm_struct *mm; 715 struct pagemapread pm; 716 int ret = -ESRCH; 717 struct mm_walk pagemap_walk = {}; 718 unsigned long src; 719 unsigned long svpfn; 720 unsigned long start_vaddr; 721 unsigned long end_vaddr; 722 int copied = 0; 723 724 if (!task) 725 goto out; 726 727 ret = -EACCES; 728 if (!ptrace_may_access(task, PTRACE_MODE_READ)) 729 goto out_task; 730 731 ret = -EINVAL; 732 /* file position must be aligned */ 733 if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES)) 734 goto out_task; 735 736 ret = 0; 737 738 if (!count) 739 goto out_task; 740 741 mm = get_task_mm(task); 742 if (!mm) 743 goto out_task; 744 745 pm.len = PM_ENTRY_BYTES * (PAGEMAP_WALK_SIZE >> PAGE_SHIFT); 746 pm.buffer = kmalloc(pm.len, GFP_TEMPORARY); 747 ret = -ENOMEM; 748 if (!pm.buffer) 749 goto out_mm; 750 751 pagemap_walk.pmd_entry = pagemap_pte_range; 752 pagemap_walk.pte_hole = pagemap_pte_hole; 753 #ifdef CONFIG_HUGETLB_PAGE 754 pagemap_walk.hugetlb_entry = pagemap_hugetlb_range; 755 #endif 756 pagemap_walk.mm = mm; 757 pagemap_walk.private = ± 758 759 src = *ppos; 760 svpfn = src / PM_ENTRY_BYTES; 761 start_vaddr = svpfn << PAGE_SHIFT; 762 end_vaddr = TASK_SIZE_OF(task); 763 764 /* watch out for wraparound */ 765 if (svpfn > TASK_SIZE_OF(task) >> PAGE_SHIFT) 766 start_vaddr = end_vaddr; 767 768 /* 769 * The odds are that this will stop walking way 770 * before end_vaddr, because the length of the 771 * user buffer is tracked in "pm", and the walk 772 * will stop when we hit the end of the buffer. 773 */ 774 ret = 0; 775 while (count && (start_vaddr < end_vaddr)) { 776 int len; 777 unsigned long end; 778 779 pm.pos = 0; 780 end = (start_vaddr + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK; 781 /* overflow ? */ 782 if (end < start_vaddr || end > end_vaddr) 783 end = end_vaddr; 784 down_read(&mm->mmap_sem); 785 ret = walk_page_range(start_vaddr, end, &pagemap_walk); 786 up_read(&mm->mmap_sem); 787 start_vaddr = end; 788 789 len = min(count, PM_ENTRY_BYTES * pm.pos); 790 if (copy_to_user(buf, pm.buffer, len)) { 791 ret = -EFAULT; 792 goto out_free; 793 } 794 copied += len; 795 buf += len; 796 count -= len; 797 } 798 *ppos += copied; 799 if (!ret || ret == PM_END_OF_BUFFER) 800 ret = copied; 801 802 out_free: 803 kfree(pm.buffer); 804 out_mm: 805 mmput(mm); 806 out_task: 807 put_task_struct(task); 808 out: 809 return ret; 810 } 811 812 const struct file_operations proc_pagemap_operations = { 813 .llseek = mem_lseek, /* borrow this */ 814 .read = pagemap_read, 815 }; 816 #endif /* CONFIG_PROC_PAGE_MONITOR */ 817 818 #ifdef CONFIG_NUMA 819 extern int show_numa_map(struct seq_file *m, void *v); 820 821 static const struct seq_operations proc_pid_numa_maps_op = { 822 .start = m_start, 823 .next = m_next, 824 .stop = m_stop, 825 .show = show_numa_map, 826 }; 827 828 static int numa_maps_open(struct inode *inode, struct file *file) 829 { 830 return do_maps_open(inode, file, &proc_pid_numa_maps_op); 831 } 832 833 const struct file_operations proc_numa_maps_operations = { 834 .open = numa_maps_open, 835 .read = seq_read, 836 .llseek = seq_lseek, 837 .release = seq_release_private, 838 }; 839 #endif 840