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 start += PAGE_SIZE; 228 229 seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n", 230 start, 231 vma->vm_end, 232 flags & VM_READ ? 'r' : '-', 233 flags & VM_WRITE ? 'w' : '-', 234 flags & VM_EXEC ? 'x' : '-', 235 flags & VM_MAYSHARE ? 's' : 'p', 236 pgoff, 237 MAJOR(dev), MINOR(dev), ino, &len); 238 239 /* 240 * Print the dentry name for named mappings, and a 241 * special [heap] marker for the heap: 242 */ 243 if (file) { 244 pad_len_spaces(m, len); 245 seq_path(m, &file->f_path, "\n"); 246 } else { 247 const char *name = arch_vma_name(vma); 248 if (!name) { 249 if (mm) { 250 if (vma->vm_start <= mm->start_brk && 251 vma->vm_end >= mm->brk) { 252 name = "[heap]"; 253 } else if (vma->vm_start <= mm->start_stack && 254 vma->vm_end >= mm->start_stack) { 255 name = "[stack]"; 256 } 257 } else { 258 name = "[vdso]"; 259 } 260 } 261 if (name) { 262 pad_len_spaces(m, len); 263 seq_puts(m, name); 264 } 265 } 266 seq_putc(m, '\n'); 267 } 268 269 static int show_map(struct seq_file *m, void *v) 270 { 271 struct vm_area_struct *vma = v; 272 struct proc_maps_private *priv = m->private; 273 struct task_struct *task = priv->task; 274 275 show_map_vma(m, vma); 276 277 if (m->count < m->size) /* vma is copied successfully */ 278 m->version = (vma != get_gate_vma(task))? vma->vm_start: 0; 279 return 0; 280 } 281 282 static const struct seq_operations proc_pid_maps_op = { 283 .start = m_start, 284 .next = m_next, 285 .stop = m_stop, 286 .show = show_map 287 }; 288 289 static int maps_open(struct inode *inode, struct file *file) 290 { 291 return do_maps_open(inode, file, &proc_pid_maps_op); 292 } 293 294 const struct file_operations proc_maps_operations = { 295 .open = maps_open, 296 .read = seq_read, 297 .llseek = seq_lseek, 298 .release = seq_release_private, 299 }; 300 301 /* 302 * Proportional Set Size(PSS): my share of RSS. 303 * 304 * PSS of a process is the count of pages it has in memory, where each 305 * page is divided by the number of processes sharing it. So if a 306 * process has 1000 pages all to itself, and 1000 shared with one other 307 * process, its PSS will be 1500. 308 * 309 * To keep (accumulated) division errors low, we adopt a 64bit 310 * fixed-point pss counter to minimize division errors. So (pss >> 311 * PSS_SHIFT) would be the real byte count. 312 * 313 * A shift of 12 before division means (assuming 4K page size): 314 * - 1M 3-user-pages add up to 8KB errors; 315 * - supports mapcount up to 2^24, or 16M; 316 * - supports PSS up to 2^52 bytes, or 4PB. 317 */ 318 #define PSS_SHIFT 12 319 320 #ifdef CONFIG_PROC_PAGE_MONITOR 321 struct mem_size_stats { 322 struct vm_area_struct *vma; 323 unsigned long resident; 324 unsigned long shared_clean; 325 unsigned long shared_dirty; 326 unsigned long private_clean; 327 unsigned long private_dirty; 328 unsigned long referenced; 329 unsigned long swap; 330 u64 pss; 331 }; 332 333 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, 334 struct mm_walk *walk) 335 { 336 struct mem_size_stats *mss = walk->private; 337 struct vm_area_struct *vma = mss->vma; 338 pte_t *pte, ptent; 339 spinlock_t *ptl; 340 struct page *page; 341 int mapcount; 342 343 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 344 for (; addr != end; pte++, addr += PAGE_SIZE) { 345 ptent = *pte; 346 347 if (is_swap_pte(ptent)) { 348 mss->swap += PAGE_SIZE; 349 continue; 350 } 351 352 if (!pte_present(ptent)) 353 continue; 354 355 page = vm_normal_page(vma, addr, ptent); 356 if (!page) 357 continue; 358 359 mss->resident += PAGE_SIZE; 360 /* Accumulate the size in pages that have been accessed. */ 361 if (pte_young(ptent) || PageReferenced(page)) 362 mss->referenced += PAGE_SIZE; 363 mapcount = page_mapcount(page); 364 if (mapcount >= 2) { 365 if (pte_dirty(ptent)) 366 mss->shared_dirty += PAGE_SIZE; 367 else 368 mss->shared_clean += PAGE_SIZE; 369 mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount; 370 } else { 371 if (pte_dirty(ptent)) 372 mss->private_dirty += PAGE_SIZE; 373 else 374 mss->private_clean += PAGE_SIZE; 375 mss->pss += (PAGE_SIZE << PSS_SHIFT); 376 } 377 } 378 pte_unmap_unlock(pte - 1, ptl); 379 cond_resched(); 380 return 0; 381 } 382 383 static int show_smap(struct seq_file *m, void *v) 384 { 385 struct proc_maps_private *priv = m->private; 386 struct task_struct *task = priv->task; 387 struct vm_area_struct *vma = v; 388 struct mem_size_stats mss; 389 struct mm_walk smaps_walk = { 390 .pmd_entry = smaps_pte_range, 391 .mm = vma->vm_mm, 392 .private = &mss, 393 }; 394 395 memset(&mss, 0, sizeof mss); 396 mss.vma = vma; 397 /* mmap_sem is held in m_start */ 398 if (vma->vm_mm && !is_vm_hugetlb_page(vma)) 399 walk_page_range(vma->vm_start, vma->vm_end, &smaps_walk); 400 401 show_map_vma(m, vma); 402 403 seq_printf(m, 404 "Size: %8lu kB\n" 405 "Rss: %8lu kB\n" 406 "Pss: %8lu kB\n" 407 "Shared_Clean: %8lu kB\n" 408 "Shared_Dirty: %8lu kB\n" 409 "Private_Clean: %8lu kB\n" 410 "Private_Dirty: %8lu kB\n" 411 "Referenced: %8lu kB\n" 412 "Swap: %8lu kB\n" 413 "KernelPageSize: %8lu kB\n" 414 "MMUPageSize: %8lu kB\n", 415 (vma->vm_end - vma->vm_start) >> 10, 416 mss.resident >> 10, 417 (unsigned long)(mss.pss >> (10 + PSS_SHIFT)), 418 mss.shared_clean >> 10, 419 mss.shared_dirty >> 10, 420 mss.private_clean >> 10, 421 mss.private_dirty >> 10, 422 mss.referenced >> 10, 423 mss.swap >> 10, 424 vma_kernel_pagesize(vma) >> 10, 425 vma_mmu_pagesize(vma) >> 10); 426 427 if (m->count < m->size) /* vma is copied successfully */ 428 m->version = (vma != get_gate_vma(task)) ? vma->vm_start : 0; 429 return 0; 430 } 431 432 static const struct seq_operations proc_pid_smaps_op = { 433 .start = m_start, 434 .next = m_next, 435 .stop = m_stop, 436 .show = show_smap 437 }; 438 439 static int smaps_open(struct inode *inode, struct file *file) 440 { 441 return do_maps_open(inode, file, &proc_pid_smaps_op); 442 } 443 444 const struct file_operations proc_smaps_operations = { 445 .open = smaps_open, 446 .read = seq_read, 447 .llseek = seq_lseek, 448 .release = seq_release_private, 449 }; 450 451 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr, 452 unsigned long end, struct mm_walk *walk) 453 { 454 struct vm_area_struct *vma = walk->private; 455 pte_t *pte, ptent; 456 spinlock_t *ptl; 457 struct page *page; 458 459 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 460 for (; addr != end; pte++, addr += PAGE_SIZE) { 461 ptent = *pte; 462 if (!pte_present(ptent)) 463 continue; 464 465 page = vm_normal_page(vma, addr, ptent); 466 if (!page) 467 continue; 468 469 /* Clear accessed and referenced bits. */ 470 ptep_test_and_clear_young(vma, addr, pte); 471 ClearPageReferenced(page); 472 } 473 pte_unmap_unlock(pte - 1, ptl); 474 cond_resched(); 475 return 0; 476 } 477 478 #define CLEAR_REFS_ALL 1 479 #define CLEAR_REFS_ANON 2 480 #define CLEAR_REFS_MAPPED 3 481 482 static ssize_t clear_refs_write(struct file *file, const char __user *buf, 483 size_t count, loff_t *ppos) 484 { 485 struct task_struct *task; 486 char buffer[PROC_NUMBUF]; 487 struct mm_struct *mm; 488 struct vm_area_struct *vma; 489 long type; 490 491 memset(buffer, 0, sizeof(buffer)); 492 if (count > sizeof(buffer) - 1) 493 count = sizeof(buffer) - 1; 494 if (copy_from_user(buffer, buf, count)) 495 return -EFAULT; 496 if (strict_strtol(strstrip(buffer), 10, &type)) 497 return -EINVAL; 498 if (type < CLEAR_REFS_ALL || type > CLEAR_REFS_MAPPED) 499 return -EINVAL; 500 task = get_proc_task(file->f_path.dentry->d_inode); 501 if (!task) 502 return -ESRCH; 503 mm = get_task_mm(task); 504 if (mm) { 505 struct mm_walk clear_refs_walk = { 506 .pmd_entry = clear_refs_pte_range, 507 .mm = mm, 508 }; 509 down_read(&mm->mmap_sem); 510 for (vma = mm->mmap; vma; vma = vma->vm_next) { 511 clear_refs_walk.private = vma; 512 if (is_vm_hugetlb_page(vma)) 513 continue; 514 /* 515 * Writing 1 to /proc/pid/clear_refs affects all pages. 516 * 517 * Writing 2 to /proc/pid/clear_refs only affects 518 * Anonymous pages. 519 * 520 * Writing 3 to /proc/pid/clear_refs only affects file 521 * mapped pages. 522 */ 523 if (type == CLEAR_REFS_ANON && vma->vm_file) 524 continue; 525 if (type == CLEAR_REFS_MAPPED && !vma->vm_file) 526 continue; 527 walk_page_range(vma->vm_start, vma->vm_end, 528 &clear_refs_walk); 529 } 530 flush_tlb_mm(mm); 531 up_read(&mm->mmap_sem); 532 mmput(mm); 533 } 534 put_task_struct(task); 535 536 return count; 537 } 538 539 const struct file_operations proc_clear_refs_operations = { 540 .write = clear_refs_write, 541 }; 542 543 struct pagemapread { 544 int pos, len; 545 u64 *buffer; 546 }; 547 548 #define PM_ENTRY_BYTES sizeof(u64) 549 #define PM_STATUS_BITS 3 550 #define PM_STATUS_OFFSET (64 - PM_STATUS_BITS) 551 #define PM_STATUS_MASK (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET) 552 #define PM_STATUS(nr) (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK) 553 #define PM_PSHIFT_BITS 6 554 #define PM_PSHIFT_OFFSET (PM_STATUS_OFFSET - PM_PSHIFT_BITS) 555 #define PM_PSHIFT_MASK (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET) 556 #define PM_PSHIFT(x) (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK) 557 #define PM_PFRAME_MASK ((1LL << PM_PSHIFT_OFFSET) - 1) 558 #define PM_PFRAME(x) ((x) & PM_PFRAME_MASK) 559 560 #define PM_PRESENT PM_STATUS(4LL) 561 #define PM_SWAP PM_STATUS(2LL) 562 #define PM_NOT_PRESENT PM_PSHIFT(PAGE_SHIFT) 563 #define PM_END_OF_BUFFER 1 564 565 static int add_to_pagemap(unsigned long addr, u64 pfn, 566 struct pagemapread *pm) 567 { 568 pm->buffer[pm->pos++] = pfn; 569 if (pm->pos >= pm->len) 570 return PM_END_OF_BUFFER; 571 return 0; 572 } 573 574 static int pagemap_pte_hole(unsigned long start, unsigned long end, 575 struct mm_walk *walk) 576 { 577 struct pagemapread *pm = walk->private; 578 unsigned long addr; 579 int err = 0; 580 for (addr = start; addr < end; addr += PAGE_SIZE) { 581 err = add_to_pagemap(addr, PM_NOT_PRESENT, pm); 582 if (err) 583 break; 584 } 585 return err; 586 } 587 588 static u64 swap_pte_to_pagemap_entry(pte_t pte) 589 { 590 swp_entry_t e = pte_to_swp_entry(pte); 591 return swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT); 592 } 593 594 static u64 pte_to_pagemap_entry(pte_t pte) 595 { 596 u64 pme = 0; 597 if (is_swap_pte(pte)) 598 pme = PM_PFRAME(swap_pte_to_pagemap_entry(pte)) 599 | PM_PSHIFT(PAGE_SHIFT) | PM_SWAP; 600 else if (pte_present(pte)) 601 pme = PM_PFRAME(pte_pfn(pte)) 602 | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT; 603 return pme; 604 } 605 606 static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, 607 struct mm_walk *walk) 608 { 609 struct vm_area_struct *vma; 610 struct pagemapread *pm = walk->private; 611 pte_t *pte; 612 int err = 0; 613 614 /* find the first VMA at or above 'addr' */ 615 vma = find_vma(walk->mm, addr); 616 for (; addr != end; addr += PAGE_SIZE) { 617 u64 pfn = PM_NOT_PRESENT; 618 619 /* check to see if we've left 'vma' behind 620 * and need a new, higher one */ 621 if (vma && (addr >= vma->vm_end)) 622 vma = find_vma(walk->mm, addr); 623 624 /* check that 'vma' actually covers this address, 625 * and that it isn't a huge page vma */ 626 if (vma && (vma->vm_start <= addr) && 627 !is_vm_hugetlb_page(vma)) { 628 pte = pte_offset_map(pmd, addr); 629 pfn = pte_to_pagemap_entry(*pte); 630 /* unmap before userspace copy */ 631 pte_unmap(pte); 632 } 633 err = add_to_pagemap(addr, pfn, pm); 634 if (err) 635 return err; 636 } 637 638 cond_resched(); 639 640 return err; 641 } 642 643 #ifdef CONFIG_HUGETLB_PAGE 644 static u64 huge_pte_to_pagemap_entry(pte_t pte, int offset) 645 { 646 u64 pme = 0; 647 if (pte_present(pte)) 648 pme = PM_PFRAME(pte_pfn(pte) + offset) 649 | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT; 650 return pme; 651 } 652 653 /* This function walks within one hugetlb entry in the single call */ 654 static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask, 655 unsigned long addr, unsigned long end, 656 struct mm_walk *walk) 657 { 658 struct pagemapread *pm = walk->private; 659 int err = 0; 660 u64 pfn; 661 662 for (; addr != end; addr += PAGE_SIZE) { 663 int offset = (addr & ~hmask) >> PAGE_SHIFT; 664 pfn = huge_pte_to_pagemap_entry(*pte, offset); 665 err = add_to_pagemap(addr, pfn, pm); 666 if (err) 667 return err; 668 } 669 670 cond_resched(); 671 672 return err; 673 } 674 #endif /* HUGETLB_PAGE */ 675 676 /* 677 * /proc/pid/pagemap - an array mapping virtual pages to pfns 678 * 679 * For each page in the address space, this file contains one 64-bit entry 680 * consisting of the following: 681 * 682 * Bits 0-55 page frame number (PFN) if present 683 * Bits 0-4 swap type if swapped 684 * Bits 5-55 swap offset if swapped 685 * Bits 55-60 page shift (page size = 1<<page shift) 686 * Bit 61 reserved for future use 687 * Bit 62 page swapped 688 * Bit 63 page present 689 * 690 * If the page is not present but in swap, then the PFN contains an 691 * encoding of the swap file number and the page's offset into the 692 * swap. Unmapped pages return a null PFN. This allows determining 693 * precisely which pages are mapped (or in swap) and comparing mapped 694 * pages between processes. 695 * 696 * Efficient users of this interface will use /proc/pid/maps to 697 * determine which areas of memory are actually mapped and llseek to 698 * skip over unmapped regions. 699 */ 700 #define PAGEMAP_WALK_SIZE (PMD_SIZE) 701 static ssize_t pagemap_read(struct file *file, char __user *buf, 702 size_t count, loff_t *ppos) 703 { 704 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode); 705 struct mm_struct *mm; 706 struct pagemapread pm; 707 int ret = -ESRCH; 708 struct mm_walk pagemap_walk = {}; 709 unsigned long src; 710 unsigned long svpfn; 711 unsigned long start_vaddr; 712 unsigned long end_vaddr; 713 int copied = 0; 714 715 if (!task) 716 goto out; 717 718 ret = -EACCES; 719 if (!ptrace_may_access(task, PTRACE_MODE_READ)) 720 goto out_task; 721 722 ret = -EINVAL; 723 /* file position must be aligned */ 724 if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES)) 725 goto out_task; 726 727 ret = 0; 728 729 if (!count) 730 goto out_task; 731 732 mm = get_task_mm(task); 733 if (!mm) 734 goto out_task; 735 736 pm.len = PM_ENTRY_BYTES * (PAGEMAP_WALK_SIZE >> PAGE_SHIFT); 737 pm.buffer = kmalloc(pm.len, GFP_TEMPORARY); 738 ret = -ENOMEM; 739 if (!pm.buffer) 740 goto out_mm; 741 742 pagemap_walk.pmd_entry = pagemap_pte_range; 743 pagemap_walk.pte_hole = pagemap_pte_hole; 744 #ifdef CONFIG_HUGETLB_PAGE 745 pagemap_walk.hugetlb_entry = pagemap_hugetlb_range; 746 #endif 747 pagemap_walk.mm = mm; 748 pagemap_walk.private = ± 749 750 src = *ppos; 751 svpfn = src / PM_ENTRY_BYTES; 752 start_vaddr = svpfn << PAGE_SHIFT; 753 end_vaddr = TASK_SIZE_OF(task); 754 755 /* watch out for wraparound */ 756 if (svpfn > TASK_SIZE_OF(task) >> PAGE_SHIFT) 757 start_vaddr = end_vaddr; 758 759 /* 760 * The odds are that this will stop walking way 761 * before end_vaddr, because the length of the 762 * user buffer is tracked in "pm", and the walk 763 * will stop when we hit the end of the buffer. 764 */ 765 ret = 0; 766 while (count && (start_vaddr < end_vaddr)) { 767 int len; 768 unsigned long end; 769 770 pm.pos = 0; 771 end = start_vaddr + PAGEMAP_WALK_SIZE; 772 /* overflow ? */ 773 if (end < start_vaddr || end > end_vaddr) 774 end = end_vaddr; 775 down_read(&mm->mmap_sem); 776 ret = walk_page_range(start_vaddr, end, &pagemap_walk); 777 up_read(&mm->mmap_sem); 778 start_vaddr = end; 779 780 len = min(count, PM_ENTRY_BYTES * pm.pos); 781 if (copy_to_user(buf, pm.buffer, len)) { 782 ret = -EFAULT; 783 goto out_free; 784 } 785 copied += len; 786 buf += len; 787 count -= len; 788 } 789 *ppos += copied; 790 if (!ret || ret == PM_END_OF_BUFFER) 791 ret = copied; 792 793 out_free: 794 kfree(pm.buffer); 795 out_mm: 796 mmput(mm); 797 out_task: 798 put_task_struct(task); 799 out: 800 return ret; 801 } 802 803 const struct file_operations proc_pagemap_operations = { 804 .llseek = mem_lseek, /* borrow this */ 805 .read = pagemap_read, 806 }; 807 #endif /* CONFIG_PROC_PAGE_MONITOR */ 808 809 #ifdef CONFIG_NUMA 810 extern int show_numa_map(struct seq_file *m, void *v); 811 812 static const struct seq_operations proc_pid_numa_maps_op = { 813 .start = m_start, 814 .next = m_next, 815 .stop = m_stop, 816 .show = show_numa_map, 817 }; 818 819 static int numa_maps_open(struct inode *inode, struct file *file) 820 { 821 return do_maps_open(inode, file, &proc_pid_numa_maps_op); 822 } 823 824 const struct file_operations proc_numa_maps_operations = { 825 .open = numa_maps_open, 826 .read = seq_read, 827 .llseek = seq_lseek, 828 .release = seq_release_private, 829 }; 830 #endif 831