fs/proc/task_mmu.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/pagewalk.h>
   3 #include <linux/mm_inline.h>
   4 #include <linux/hugetlb.h>
   5 #include <linux/huge_mm.h>
   6 #include <linux/mount.h>
   7 #include <linux/ksm.h>
   8 #include <linux/seq_file.h>
   9 #include <linux/highmem.h>
  10 #include <linux/ptrace.h>
  11 #include <linux/slab.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/mempolicy.h>
  14 #include <linux/rmap.h>
  15 #include <linux/swap.h>
  16 #include <linux/sched/mm.h>
  17 #include <linux/swapops.h>
  18 #include <linux/mmu_notifier.h>
  19 #include <linux/page_idle.h>
  20 #include <linux/shmem_fs.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/pkeys.h>
  23 #include <linux/minmax.h>
  24 #include <linux/overflow.h>
  25
  26 #include <asm/elf.h>
  27 #include <asm/tlb.h>
  28 #include <asm/tlbflush.h>
  29 #include "internal.h"
  30
  31 #define SEQ_PUT_DEC(str, val) \
  32                 seq_put_decimal_ull_width(m, str, (val) << (PAGE_SHIFT-10), 8)
  33 void task_mem(struct seq_file *m, struct mm_struct *mm)
  34 {
  35         unsigned long text, lib, swap, anon, file, shmem;
  36         unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
  37
  38         anon = get_mm_counter(mm, MM_ANONPAGES);
  39         file = get_mm_counter(mm, MM_FILEPAGES);
  40         shmem = get_mm_counter(mm, MM_SHMEMPAGES);
  41
  42         /*
  43          * Note: to minimize their overhead, mm maintains hiwater_vm and
  44          * hiwater_rss only when about to *lower* total_vm or rss.  Any
  45          * collector of these hiwater stats must therefore get total_vm
  46          * and rss too, which will usually be the higher.  Barriers? not
  47          * worth the effort, such snapshots can always be inconsistent.
  48          */
  49         hiwater_vm = total_vm = mm->total_vm;
  50         if (hiwater_vm < mm->hiwater_vm)
  51                 hiwater_vm = mm->hiwater_vm;
  52         hiwater_rss = total_rss = anon + file + shmem;
  53         if (hiwater_rss < mm->hiwater_rss)
  54                 hiwater_rss = mm->hiwater_rss;
  55
  56         /* split executable areas between text and lib */
  57         text = PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK);
  58         text = min(text, mm->exec_vm << PAGE_SHIFT);
  59         lib = (mm->exec_vm << PAGE_SHIFT) - text;
  60
  61         swap = get_mm_counter(mm, MM_SWAPENTS);
  62         SEQ_PUT_DEC("VmPeak:\t", hiwater_vm);
  63         SEQ_PUT_DEC(" kB\nVmSize:\t", total_vm);
  64         SEQ_PUT_DEC(" kB\nVmLck:\t", mm->locked_vm);
  65         SEQ_PUT_DEC(" kB\nVmPin:\t", atomic64_read(&mm->pinned_vm));
  66         SEQ_PUT_DEC(" kB\nVmHWM:\t", hiwater_rss);
  67         SEQ_PUT_DEC(" kB\nVmRSS:\t", total_rss);
  68         SEQ_PUT_DEC(" kB\nRssAnon:\t", anon);
  69         SEQ_PUT_DEC(" kB\nRssFile:\t", file);
  70         SEQ_PUT_DEC(" kB\nRssShmem:\t", shmem);
  71         SEQ_PUT_DEC(" kB\nVmData:\t", mm->data_vm);
  72         SEQ_PUT_DEC(" kB\nVmStk:\t", mm->stack_vm);
  73         seq_put_decimal_ull_width(m,
  74                     " kB\nVmExe:\t", text >> 10, 8);
  75         seq_put_decimal_ull_width(m,
  76                     " kB\nVmLib:\t", lib >> 10, 8);
  77         seq_put_decimal_ull_width(m,
  78                     " kB\nVmPTE:\t", mm_pgtables_bytes(mm) >> 10, 8);
  79         SEQ_PUT_DEC(" kB\nVmSwap:\t", swap);
  80         seq_puts(m, " kB\n");
  81         hugetlb_report_usage(m, mm);
  82 }
  83 #undef SEQ_PUT_DEC
  84
  85 unsigned long task_vsize(struct mm_struct *mm)
  86 {
  87         return PAGE_SIZE * mm->total_vm;
  88 }
  89
  90 unsigned long task_statm(struct mm_struct *mm,
  91                          unsigned long *shared, unsigned long *text,
  92                          unsigned long *data, unsigned long *resident)
  93 {
  94         *shared = get_mm_counter(mm, MM_FILEPAGES) +
  95                         get_mm_counter(mm, MM_SHMEMPAGES);
  96         *text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
  97                                                                 >> PAGE_SHIFT;
  98         *data = mm->data_vm + mm->stack_vm;
  99         *resident = *shared + get_mm_counter(mm, MM_ANONPAGES);
 100         return mm->total_vm;
 101 }
 102
 103 #ifdef CONFIG_NUMA
 104 /*
 105  * Save get_task_policy() for show_numa_map().
 106  */
 107 static void hold_task_mempolicy(struct proc_maps_private *priv)
 108 {
 109         struct task_struct *task = priv->task;
 110
 111         task_lock(task);
 112         priv->task_mempolicy = get_task_policy(task);
 113         mpol_get(priv->task_mempolicy);
 114         task_unlock(task);
 115 }
 116 static void release_task_mempolicy(struct proc_maps_private *priv)
 117 {
 118         mpol_put(priv->task_mempolicy);
 119 }
 120 #else
 121 static void hold_task_mempolicy(struct proc_maps_private *priv)
 122 {
 123 }
 124 static void release_task_mempolicy(struct proc_maps_private *priv)
 125 {
 126 }
 127 #endif
 128
 129 static struct vm_area_struct *proc_get_vma(struct proc_maps_private *priv,
 130                                                 loff_t *ppos)
 131 {
 132         struct vm_area_struct *vma = vma_next(&priv->iter);
 133
 134         if (vma) {
 135                 *ppos = vma->vm_start;
 136         } else {
 137                 *ppos = -2UL;
 138                 vma = get_gate_vma(priv->mm);
 139         }
 140
 141         return vma;
 142 }
 143
 144 static void *m_start(struct seq_file *m, loff_t *ppos)
 145 {
 146         struct proc_maps_private *priv = m->private;
 147         unsigned long last_addr = *ppos;
 148         struct mm_struct *mm;
 149
 150         /* See m_next(). Zero at the start or after lseek. */
 151         if (last_addr == -1UL)
 152                 return NULL;
 153
 154         priv->task = get_proc_task(priv->inode);
 155         if (!priv->task)
 156                 return ERR_PTR(-ESRCH);
 157
 158         mm = priv->mm;
 159         if (!mm || !mmget_not_zero(mm)) {
 160                 put_task_struct(priv->task);
 161                 priv->task = NULL;
 162                 return NULL;
 163         }
 164
 165         if (mmap_read_lock_killable(mm)) {
 166                 mmput(mm);
 167                 put_task_struct(priv->task);
 168                 priv->task = NULL;
 169                 return ERR_PTR(-EINTR);
 170         }
 171
 172         vma_iter_init(&priv->iter, mm, last_addr);
 173         hold_task_mempolicy(priv);
 174         if (last_addr == -2UL)
 175                 return get_gate_vma(mm);
 176
 177         return proc_get_vma(priv, ppos);
 178 }
 179
 180 static void *m_next(struct seq_file *m, void *v, loff_t *ppos)
 181 {
 182         if (*ppos == -2UL) {
 183                 *ppos = -1UL;
 184                 return NULL;
 185         }
 186         return proc_get_vma(m->private, ppos);
 187 }
 188
 189 static void m_stop(struct seq_file *m, void *v)
 190 {
 191         struct proc_maps_private *priv = m->private;
 192         struct mm_struct *mm = priv->mm;
 193
 194         if (!priv->task)
 195                 return;
 196
 197         release_task_mempolicy(priv);
 198         mmap_read_unlock(mm);
 199         mmput(mm);
 200         put_task_struct(priv->task);
 201         priv->task = NULL;
 202 }
 203
 204 static int proc_maps_open(struct inode *inode, struct file *file,
 205                         const struct seq_operations *ops, int psize)
 206 {
 207         struct proc_maps_private *priv = __seq_open_private(file, ops, psize);
 208
 209         if (!priv)
 210                 return -ENOMEM;
 211
 212         priv->inode = inode;
 213         priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
 214         if (IS_ERR(priv->mm)) {
 215                 int err = PTR_ERR(priv->mm);
 216
 217                 seq_release_private(inode, file);
 218                 return err;
 219         }
 220
 221         return 0;
 222 }
 223
 224 static int proc_map_release(struct inode *inode, struct file *file)
 225 {
 226         struct seq_file *seq = file->private_data;
 227         struct proc_maps_private *priv = seq->private;
 228
 229         if (priv->mm)
 230                 mmdrop(priv->mm);
 231
 232         return seq_release_private(inode, file);
 233 }
 234
 235 static int do_maps_open(struct inode *inode, struct file *file,
 236                         const struct seq_operations *ops)
 237 {
 238         return proc_maps_open(inode, file, ops,
 239                                 sizeof(struct proc_maps_private));
 240 }
 241
 242 static void show_vma_header_prefix(struct seq_file *m,
 243                                    unsigned long start, unsigned long end,
 244                                    vm_flags_t flags, unsigned long long pgoff,
 245                                    dev_t dev, unsigned long ino)
 246 {
 247         seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
 248         seq_put_hex_ll(m, NULL, start, 8);
 249         seq_put_hex_ll(m, "-", end, 8);
 250         seq_putc(m, ' ');
 251         seq_putc(m, flags & VM_READ ? 'r' : '-');
 252         seq_putc(m, flags & VM_WRITE ? 'w' : '-');
 253         seq_putc(m, flags & VM_EXEC ? 'x' : '-');
 254         seq_putc(m, flags & VM_MAYSHARE ? 's' : 'p');
 255         seq_put_hex_ll(m, " ", pgoff, 8);
 256         seq_put_hex_ll(m, " ", MAJOR(dev), 2);
 257         seq_put_hex_ll(m, ":", MINOR(dev), 2);
 258         seq_put_decimal_ull(m, " ", ino);
 259         seq_putc(m, ' ');
 260 }
 261
 262 static void
 263 show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
 264 {
 265         struct anon_vma_name *anon_name = NULL;
 266         struct mm_struct *mm = vma->vm_mm;
 267         struct file *file = vma->vm_file;
 268         vm_flags_t flags = vma->vm_flags;
 269         unsigned long ino = 0;
 270         unsigned long long pgoff = 0;
 271         unsigned long start, end;
 272         dev_t dev = 0;
 273         const char *name = NULL;
 274
 275         if (file) {
 276                 const struct inode *inode = file_user_inode(vma->vm_file);
 277
 278                 dev = inode->i_sb->s_dev;
 279                 ino = inode->i_ino;
 280                 pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
 281         }
 282
 283         start = vma->vm_start;
 284         end = vma->vm_end;
 285         show_vma_header_prefix(m, start, end, flags, pgoff, dev, ino);
 286         if (mm)
 287                 anon_name = anon_vma_name(vma);
 288
 289         /*
 290          * Print the dentry name for named mappings, and a
 291          * special [heap] marker for the heap:
 292          */
 293         if (file) {
 294                 seq_pad(m, ' ');
 295                 /*
 296                  * If user named this anon shared memory via
 297                  * prctl(PR_SET_VMA ..., use the provided name.
 298                  */
 299                 if (anon_name)
 300                         seq_printf(m, "[anon_shmem:%s]", anon_name->name);
 301                 else
 302                         seq_path(m, file_user_path(file), "\n");
 303                 goto done;
 304         }
 305
 306         if (vma->vm_ops && vma->vm_ops->name) {
 307                 name = vma->vm_ops->name(vma);
 308                 if (name)
 309                         goto done;
 310         }
 311
 312         name = arch_vma_name(vma);
 313         if (!name) {
 314                 if (!mm) {
 315                         name = "[vdso]";
 316                         goto done;
 317                 }
 318
 319                 if (vma_is_initial_heap(vma)) {
 320                         name = "[heap]";
 321                         goto done;
 322                 }
 323
 324                 if (vma_is_initial_stack(vma)) {
 325                         name = "[stack]";
 326                         goto done;
 327                 }
 328
 329                 if (anon_name) {
 330                         seq_pad(m, ' ');
 331                         seq_printf(m, "[anon:%s]", anon_name->name);
 332                 }
 333         }
 334
 335 done:
 336         if (name) {
 337                 seq_pad(m, ' ');
 338                 seq_puts(m, name);
 339         }
 340         seq_putc(m, '\n');
 341 }
 342
 343 static int show_map(struct seq_file *m, void *v)
 344 {
 345         show_map_vma(m, v);
 346         return 0;
 347 }
 348
 349 static const struct seq_operations proc_pid_maps_op = {
 350         .start  = m_start,
 351         .next   = m_next,
 352         .stop   = m_stop,
 353         .show   = show_map
 354 };
 355
 356 static int pid_maps_open(struct inode *inode, struct file *file)
 357 {
 358         return do_maps_open(inode, file, &proc_pid_maps_op);
 359 }
 360
 361 const struct file_operations proc_pid_maps_operations = {
 362         .open           = pid_maps_open,
 363         .read           = seq_read,
 364         .llseek         = seq_lseek,
 365         .release        = proc_map_release,
 366 };
 367
 368 /*
 369  * Proportional Set Size(PSS): my share of RSS.
 370  *
 371  * PSS of a process is the count of pages it has in memory, where each
 372  * page is divided by the number of processes sharing it.  So if a
 373  * process has 1000 pages all to itself, and 1000 shared with one other
 374  * process, its PSS will be 1500.
 375  *
 376  * To keep (accumulated) division errors low, we adopt a 64bit
 377  * fixed-point pss counter to minimize division errors. So (pss >>
 378  * PSS_SHIFT) would be the real byte count.
 379  *
 380  * A shift of 12 before division means (assuming 4K page size):
 381  *      - 1M 3-user-pages add up to 8KB errors;
 382  *      - supports mapcount up to 2^24, or 16M;
 383  *      - supports PSS up to 2^52 bytes, or 4PB.
 384  */
 385 #define PSS_SHIFT 12
 386
 387 #ifdef CONFIG_PROC_PAGE_MONITOR
 388 struct mem_size_stats {
 389         unsigned long resident;
 390         unsigned long shared_clean;
 391         unsigned long shared_dirty;
 392         unsigned long private_clean;
 393         unsigned long private_dirty;
 394         unsigned long referenced;
 395         unsigned long anonymous;
 396         unsigned long lazyfree;
 397         unsigned long anonymous_thp;
 398         unsigned long shmem_thp;
 399         unsigned long file_thp;
 400         unsigned long swap;
 401         unsigned long shared_hugetlb;
 402         unsigned long private_hugetlb;
 403         unsigned long ksm;
 404         u64 pss;
 405         u64 pss_anon;
 406         u64 pss_file;
 407         u64 pss_shmem;
 408         u64 pss_dirty;
 409         u64 pss_locked;
 410         u64 swap_pss;
 411 };
 412
 413 static void smaps_page_accumulate(struct mem_size_stats *mss,
 414                 struct page *page, unsigned long size, unsigned long pss,
 415                 bool dirty, bool locked, bool private)
 416 {
 417         mss->pss += pss;
 418
 419         if (PageAnon(page))
 420                 mss->pss_anon += pss;
 421         else if (PageSwapBacked(page))
 422                 mss->pss_shmem += pss;
 423         else
 424                 mss->pss_file += pss;
 425
 426         if (locked)
 427                 mss->pss_locked += pss;
 428
 429         if (dirty || PageDirty(page)) {
 430                 mss->pss_dirty += pss;
 431                 if (private)
 432                         mss->private_dirty += size;
 433                 else
 434                         mss->shared_dirty += size;
 435         } else {
 436                 if (private)
 437                         mss->private_clean += size;
 438                 else
 439                         mss->shared_clean += size;
 440         }
 441 }
 442
 443 static void smaps_account(struct mem_size_stats *mss, struct page *page,
 444                 bool compound, bool young, bool dirty, bool locked,
 445                 bool migration)
 446 {
 447         int i, nr = compound ? compound_nr(page) : 1;
 448         unsigned long size = nr * PAGE_SIZE;
 449
 450         /*
 451          * First accumulate quantities that depend only on |size| and the type
 452          * of the compound page.
 453          */
 454         if (PageAnon(page)) {
 455                 mss->anonymous += size;
 456                 if (!PageSwapBacked(page) && !dirty && !PageDirty(page))
 457                         mss->lazyfree += size;
 458         }
 459
 460         if (PageKsm(page))
 461                 mss->ksm += size;
 462
 463         mss->resident += size;
 464         /* Accumulate the size in pages that have been accessed. */
 465         if (young || page_is_young(page) || PageReferenced(page))
 466                 mss->referenced += size;
 467
 468         /*
 469          * Then accumulate quantities that may depend on sharing, or that may
 470          * differ page-by-page.
 471          *
 472          * page_count(page) == 1 guarantees the page is mapped exactly once.
 473          * If any subpage of the compound page mapped with PTE it would elevate
 474          * page_count().
 475          *
 476          * The page_mapcount() is called to get a snapshot of the mapcount.
 477          * Without holding the page lock this snapshot can be slightly wrong as
 478          * we cannot always read the mapcount atomically.  It is not safe to
 479          * call page_mapcount() even with PTL held if the page is not mapped,
 480          * especially for migration entries.  Treat regular migration entries
 481          * as mapcount == 1.
 482          */
 483         if ((page_count(page) == 1) || migration) {
 484                 smaps_page_accumulate(mss, page, size, size << PSS_SHIFT, dirty,
 485                         locked, true);
 486                 return;
 487         }
 488         for (i = 0; i < nr; i++, page++) {
 489                 int mapcount = page_mapcount(page);
 490                 unsigned long pss = PAGE_SIZE << PSS_SHIFT;
 491                 if (mapcount >= 2)
 492                         pss /= mapcount;
 493                 smaps_page_accumulate(mss, page, PAGE_SIZE, pss, dirty, locked,
 494                                       mapcount < 2);
 495         }
 496 }
 497
 498 #ifdef CONFIG_SHMEM
 499 static int smaps_pte_hole(unsigned long addr, unsigned long end,
 500                           __always_unused int depth, struct mm_walk *walk)
 501 {
 502         struct mem_size_stats *mss = walk->private;
 503         struct vm_area_struct *vma = walk->vma;
 504
 505         mss->swap += shmem_partial_swap_usage(walk->vma->vm_file->f_mapping,
 506                                               linear_page_index(vma, addr),
 507                                               linear_page_index(vma, end));
 508
 509         return 0;
 510 }
 511 #else
 512 #define smaps_pte_hole          NULL
 513 #endif /* CONFIG_SHMEM */
 514
 515 static void smaps_pte_hole_lookup(unsigned long addr, struct mm_walk *walk)
 516 {
 517 #ifdef CONFIG_SHMEM
 518         if (walk->ops->pte_hole) {
 519                 /* depth is not used */
 520                 smaps_pte_hole(addr, addr + PAGE_SIZE, 0, walk);
 521         }
 522 #endif
 523 }
 524
 525 static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 526                 struct mm_walk *walk)
 527 {
 528         struct mem_size_stats *mss = walk->private;
 529         struct vm_area_struct *vma = walk->vma;
 530         bool locked = !!(vma->vm_flags & VM_LOCKED);
 531         struct page *page = NULL;
 532         bool migration = false, young = false, dirty = false;
 533         pte_t ptent = ptep_get(pte);
 534
 535         if (pte_present(ptent)) {
 536                 page = vm_normal_page(vma, addr, ptent);
 537                 young = pte_young(ptent);
 538                 dirty = pte_dirty(ptent);
 539         } else if (is_swap_pte(ptent)) {
 540                 swp_entry_t swpent = pte_to_swp_entry(ptent);
 541
 542                 if (!non_swap_entry(swpent)) {
 543                         int mapcount;
 544
 545                         mss->swap += PAGE_SIZE;
 546                         mapcount = swp_swapcount(swpent);
 547                         if (mapcount >= 2) {
 548                                 u64 pss_delta = (u64)PAGE_SIZE << PSS_SHIFT;
 549
 550                                 do_div(pss_delta, mapcount);
 551                                 mss->swap_pss += pss_delta;
 552                         } else {
 553                                 mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT;
 554                         }
 555                 } else if (is_pfn_swap_entry(swpent)) {
 556                         if (is_migration_entry(swpent))
 557                                 migration = true;
 558                         page = pfn_swap_entry_to_page(swpent);
 559                 }
 560         } else {
 561                 smaps_pte_hole_lookup(addr, walk);
 562                 return;
 563         }
 564
 565         if (!page)
 566                 return;
 567
 568         smaps_account(mss, page, false, young, dirty, locked, migration);
 569 }
 570
 571 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 572 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 573                 struct mm_walk *walk)
 574 {
 575         struct mem_size_stats *mss = walk->private;
 576         struct vm_area_struct *vma = walk->vma;
 577         bool locked = !!(vma->vm_flags & VM_LOCKED);
 578         struct page *page = NULL;
 579         bool migration = false;
 580
 581         if (pmd_present(*pmd)) {
 582                 page = vm_normal_page_pmd(vma, addr, *pmd);
 583         } else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) {
 584                 swp_entry_t entry = pmd_to_swp_entry(*pmd);
 585
 586                 if (is_migration_entry(entry)) {
 587                         migration = true;
 588                         page = pfn_swap_entry_to_page(entry);
 589                 }
 590         }
 591         if (IS_ERR_OR_NULL(page))
 592                 return;
 593         if (PageAnon(page))
 594                 mss->anonymous_thp += HPAGE_PMD_SIZE;
 595         else if (PageSwapBacked(page))
 596                 mss->shmem_thp += HPAGE_PMD_SIZE;
 597         else if (is_zone_device_page(page))
 598                 /* pass */;
 599         else
 600                 mss->file_thp += HPAGE_PMD_SIZE;
 601
 602         smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd),
 603                       locked, migration);
 604 }
 605 #else
 606 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 607                 struct mm_walk *walk)
 608 {
 609 }
 610 #endif
 611
 612 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 613                            struct mm_walk *walk)
 614 {
 615         struct vm_area_struct *vma = walk->vma;
 616         pte_t *pte;
 617         spinlock_t *ptl;
 618
 619         ptl = pmd_trans_huge_lock(pmd, vma);
 620         if (ptl) {
 621                 smaps_pmd_entry(pmd, addr, walk);
 622                 spin_unlock(ptl);
 623                 goto out;
 624         }
 625
 626         pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
 627         if (!pte) {
 628                 walk->action = ACTION_AGAIN;
 629                 return 0;
 630         }
 631         for (; addr != end; pte++, addr += PAGE_SIZE)
 632                 smaps_pte_entry(pte, addr, walk);
 633         pte_unmap_unlock(pte - 1, ptl);
 634 out:
 635         cond_resched();
 636         return 0;
 637 }
 638
 639 static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
 640 {
 641         /*
 642          * Don't forget to update Documentation/ on changes.
 643          */
 644         static const char mnemonics[BITS_PER_LONG][2] = {
 645                 /*
 646                  * In case if we meet a flag we don't know about.
 647                  */
 648                 [0 ... (BITS_PER_LONG-1)] = "??",
 649
 650                 [ilog2(VM_READ)]        = "rd",
 651                 [ilog2(VM_WRITE)]       = "wr",
 652                 [ilog2(VM_EXEC)]        = "ex",
 653                 [ilog2(VM_SHARED)]      = "sh",
 654                 [ilog2(VM_MAYREAD)]     = "mr",
 655                 [ilog2(VM_MAYWRITE)]    = "mw",
 656                 [ilog2(VM_MAYEXEC)]     = "me",
 657                 [ilog2(VM_MAYSHARE)]    = "ms",
 658                 [ilog2(VM_GROWSDOWN)]   = "gd",
 659                 [ilog2(VM_PFNMAP)]      = "pf",
 660                 [ilog2(VM_LOCKED)]      = "lo",
 661                 [ilog2(VM_IO)]          = "io",
 662                 [ilog2(VM_SEQ_READ)]    = "sr",
 663                 [ilog2(VM_RAND_READ)]   = "rr",
 664                 [ilog2(VM_DONTCOPY)]    = "dc",
 665                 [ilog2(VM_DONTEXPAND)]  = "de",
 666                 [ilog2(VM_LOCKONFAULT)] = "lf",
 667                 [ilog2(VM_ACCOUNT)]     = "ac",
 668                 [ilog2(VM_NORESERVE)]   = "nr",
 669                 [ilog2(VM_HUGETLB)]     = "ht",
 670                 [ilog2(VM_SYNC)]        = "sf",
 671                 [ilog2(VM_ARCH_1)]      = "ar",
 672                 [ilog2(VM_WIPEONFORK)]  = "wf",
 673                 [ilog2(VM_DONTDUMP)]    = "dd",
 674 #ifdef CONFIG_ARM64_BTI
 675                 [ilog2(VM_ARM64_BTI)]   = "bt",
 676 #endif
 677 #ifdef CONFIG_MEM_SOFT_DIRTY
 678                 [ilog2(VM_SOFTDIRTY)]   = "sd",
 679 #endif
 680                 [ilog2(VM_MIXEDMAP)]    = "mm",
 681                 [ilog2(VM_HUGEPAGE)]    = "hg",
 682                 [ilog2(VM_NOHUGEPAGE)]  = "nh",
 683                 [ilog2(VM_MERGEABLE)]   = "mg",
 684                 [ilog2(VM_UFFD_MISSING)]= "um",
 685                 [ilog2(VM_UFFD_WP)]     = "uw",
 686 #ifdef CONFIG_ARM64_MTE
 687                 [ilog2(VM_MTE)]         = "mt",
 688                 [ilog2(VM_MTE_ALLOWED)] = "",
 689 #endif
 690 #ifdef CONFIG_ARCH_HAS_PKEYS
 691                 /* These come out via ProtectionKey: */
 692                 [ilog2(VM_PKEY_BIT0)]   = "",
 693                 [ilog2(VM_PKEY_BIT1)]   = "",
 694                 [ilog2(VM_PKEY_BIT2)]   = "",
 695                 [ilog2(VM_PKEY_BIT3)]   = "",
 696 #if VM_PKEY_BIT4
 697                 [ilog2(VM_PKEY_BIT4)]   = "",
 698 #endif
 699 #endif /* CONFIG_ARCH_HAS_PKEYS */
 700 #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
 701                 [ilog2(VM_UFFD_MINOR)]  = "ui",
 702 #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
 703 #ifdef CONFIG_X86_USER_SHADOW_STACK
 704                 [ilog2(VM_SHADOW_STACK)] = "ss",
 705 #endif
 706         };
 707         size_t i;
 708
 709         seq_puts(m, "VmFlags: ");
 710         for (i = 0; i < BITS_PER_LONG; i++) {
 711                 if (!mnemonics[i][0])
 712                         continue;
 713                 if (vma->vm_flags & (1UL << i)) {
 714                         seq_putc(m, mnemonics[i][0]);
 715                         seq_putc(m, mnemonics[i][1]);
 716                         seq_putc(m, ' ');
 717                 }
 718         }
 719         seq_putc(m, '\n');
 720 }
 721
 722 #ifdef CONFIG_HUGETLB_PAGE
 723 static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
 724                                  unsigned long addr, unsigned long end,
 725                                  struct mm_walk *walk)
 726 {
 727         struct mem_size_stats *mss = walk->private;
 728         struct vm_area_struct *vma = walk->vma;
 729         struct page *page = NULL;
 730         pte_t ptent = ptep_get(pte);
 731
 732         if (pte_present(ptent)) {
 733                 page = vm_normal_page(vma, addr, ptent);
 734         } else if (is_swap_pte(ptent)) {
 735                 swp_entry_t swpent = pte_to_swp_entry(ptent);
 736
 737                 if (is_pfn_swap_entry(swpent))
 738                         page = pfn_swap_entry_to_page(swpent);
 739         }
 740         if (page) {
 741                 if (page_mapcount(page) >= 2 || hugetlb_pmd_shared(pte))
 742                         mss->shared_hugetlb += huge_page_size(hstate_vma(vma));
 743                 else
 744                         mss->private_hugetlb += huge_page_size(hstate_vma(vma));
 745         }
 746         return 0;
 747 }
 748 #else
 749 #define smaps_hugetlb_range     NULL
 750 #endif /* HUGETLB_PAGE */
 751
 752 static const struct mm_walk_ops smaps_walk_ops = {
 753         .pmd_entry              = smaps_pte_range,
 754         .hugetlb_entry          = smaps_hugetlb_range,
 755         .walk_lock              = PGWALK_RDLOCK,
 756 };
 757
 758 static const struct mm_walk_ops smaps_shmem_walk_ops = {
 759         .pmd_entry              = smaps_pte_range,
 760         .hugetlb_entry          = smaps_hugetlb_range,
 761         .pte_hole               = smaps_pte_hole,
 762         .walk_lock              = PGWALK_RDLOCK,
 763 };
 764
 765 /*
 766  * Gather mem stats from @vma with the indicated beginning
 767  * address @start, and keep them in @mss.
 768  *
 769  * Use vm_start of @vma as the beginning address if @start is 0.
 770  */
 771 static void smap_gather_stats(struct vm_area_struct *vma,
 772                 struct mem_size_stats *mss, unsigned long start)
 773 {
 774         const struct mm_walk_ops *ops = &smaps_walk_ops;
 775
 776         /* Invalid start */
 777         if (start >= vma->vm_end)
 778                 return;
 779
 780         if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) {
 781                 /*
 782                  * For shared or readonly shmem mappings we know that all
 783                  * swapped out pages belong to the shmem object, and we can
 784                  * obtain the swap value much more efficiently. For private
 785                  * writable mappings, we might have COW pages that are
 786                  * not affected by the parent swapped out pages of the shmem
 787                  * object, so we have to distinguish them during the page walk.
 788                  * Unless we know that the shmem object (or the part mapped by
 789                  * our VMA) has no swapped out pages at all.
 790                  */
 791                 unsigned long shmem_swapped = shmem_swap_usage(vma);
 792
 793                 if (!start && (!shmem_swapped || (vma->vm_flags & VM_SHARED) ||
 794                                         !(vma->vm_flags & VM_WRITE))) {
 795                         mss->swap += shmem_swapped;
 796                 } else {
 797                         ops = &smaps_shmem_walk_ops;
 798                 }
 799         }
 800
 801         /* mmap_lock is held in m_start */
 802         if (!start)
 803                 walk_page_vma(vma, ops, mss);
 804         else
 805                 walk_page_range(vma->vm_mm, start, vma->vm_end, ops, mss);
 806 }
 807
 808 #define SEQ_PUT_DEC(str, val) \
 809                 seq_put_decimal_ull_width(m, str, (val) >> 10, 8)
 810
 811 /* Show the contents common for smaps and smaps_rollup */
 812 static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss,
 813         bool rollup_mode)
 814 {
 815         SEQ_PUT_DEC("Rss:            ", mss->resident);
 816         SEQ_PUT_DEC(" kB\nPss:            ", mss->pss >> PSS_SHIFT);
 817         SEQ_PUT_DEC(" kB\nPss_Dirty:      ", mss->pss_dirty >> PSS_SHIFT);
 818         if (rollup_mode) {
 819                 /*
 820                  * These are meaningful only for smaps_rollup, otherwise two of
 821                  * them are zero, and the other one is the same as Pss.
 822                  */
 823                 SEQ_PUT_DEC(" kB\nPss_Anon:       ",
 824                         mss->pss_anon >> PSS_SHIFT);
 825                 SEQ_PUT_DEC(" kB\nPss_File:       ",
 826                         mss->pss_file >> PSS_SHIFT);
 827                 SEQ_PUT_DEC(" kB\nPss_Shmem:      ",
 828                         mss->pss_shmem >> PSS_SHIFT);
 829         }
 830         SEQ_PUT_DEC(" kB\nShared_Clean:   ", mss->shared_clean);
 831         SEQ_PUT_DEC(" kB\nShared_Dirty:   ", mss->shared_dirty);
 832         SEQ_PUT_DEC(" kB\nPrivate_Clean:  ", mss->private_clean);
 833         SEQ_PUT_DEC(" kB\nPrivate_Dirty:  ", mss->private_dirty);
 834         SEQ_PUT_DEC(" kB\nReferenced:     ", mss->referenced);
 835         SEQ_PUT_DEC(" kB\nAnonymous:      ", mss->anonymous);
 836         SEQ_PUT_DEC(" kB\nKSM:            ", mss->ksm);
 837         SEQ_PUT_DEC(" kB\nLazyFree:       ", mss->lazyfree);
 838         SEQ_PUT_DEC(" kB\nAnonHugePages:  ", mss->anonymous_thp);
 839         SEQ_PUT_DEC(" kB\nShmemPmdMapped: ", mss->shmem_thp);
 840         SEQ_PUT_DEC(" kB\nFilePmdMapped:  ", mss->file_thp);
 841         SEQ_PUT_DEC(" kB\nShared_Hugetlb: ", mss->shared_hugetlb);
 842         seq_put_decimal_ull_width(m, " kB\nPrivate_Hugetlb: ",
 843                                   mss->private_hugetlb >> 10, 7);
 844         SEQ_PUT_DEC(" kB\nSwap:           ", mss->swap);
 845         SEQ_PUT_DEC(" kB\nSwapPss:        ",
 846                                         mss->swap_pss >> PSS_SHIFT);
 847         SEQ_PUT_DEC(" kB\nLocked:         ",
 848                                         mss->pss_locked >> PSS_SHIFT);
 849         seq_puts(m, " kB\n");
 850 }
 851
 852 static int show_smap(struct seq_file *m, void *v)
 853 {
 854         struct vm_area_struct *vma = v;
 855         struct mem_size_stats mss = {};
 856
 857         smap_gather_stats(vma, &mss, 0);
 858
 859         show_map_vma(m, vma);
 860
 861         SEQ_PUT_DEC("Size:           ", vma->vm_end - vma->vm_start);
 862         SEQ_PUT_DEC(" kB\nKernelPageSize: ", vma_kernel_pagesize(vma));
 863         SEQ_PUT_DEC(" kB\nMMUPageSize:    ", vma_mmu_pagesize(vma));
 864         seq_puts(m, " kB\n");
 865
 866         __show_smap(m, &mss, false);
 867
 868         seq_printf(m, "THPeligible:    %8u\n",
 869                    hugepage_vma_check(vma, vma->vm_flags, true, false, true));
 870
 871         if (arch_pkeys_enabled())
 872                 seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));
 873         show_smap_vma_flags(m, vma);
 874
 875         return 0;
 876 }
 877
 878 static int show_smaps_rollup(struct seq_file *m, void *v)
 879 {
 880         struct proc_maps_private *priv = m->private;
 881         struct mem_size_stats mss = {};
 882         struct mm_struct *mm = priv->mm;
 883         struct vm_area_struct *vma;
 884         unsigned long vma_start = 0, last_vma_end = 0;
 885         int ret = 0;
 886         VMA_ITERATOR(vmi, mm, 0);
 887
 888         priv->task = get_proc_task(priv->inode);
 889         if (!priv->task)
 890                 return -ESRCH;
 891
 892         if (!mm || !mmget_not_zero(mm)) {
 893                 ret = -ESRCH;
 894                 goto out_put_task;
 895         }
 896
 897         ret = mmap_read_lock_killable(mm);
 898         if (ret)
 899                 goto out_put_mm;
 900
 901         hold_task_mempolicy(priv);
 902         vma = vma_next(&vmi);
 903
 904         if (unlikely(!vma))
 905                 goto empty_set;
 906
 907         vma_start = vma->vm_start;
 908         do {
 909                 smap_gather_stats(vma, &mss, 0);
 910                 last_vma_end = vma->vm_end;
 911
 912                 /*
 913                  * Release mmap_lock temporarily if someone wants to
 914                  * access it for write request.
 915                  */
 916                 if (mmap_lock_is_contended(mm)) {
 917                         vma_iter_invalidate(&vmi);
 918                         mmap_read_unlock(mm);
 919                         ret = mmap_read_lock_killable(mm);
 920                         if (ret) {
 921                                 release_task_mempolicy(priv);
 922                                 goto out_put_mm;
 923                         }
 924
 925                         /*
 926                          * After dropping the lock, there are four cases to
 927                          * consider. See the following example for explanation.
 928                          *
 929                          *   +------+------+-----------+
 930                          *   | VMA1 | VMA2 | VMA3      |
 931                          *   +------+------+-----------+
 932                          *   |      |      |           |
 933                          *  4k     8k     16k         400k
 934                          *
 935                          * Suppose we drop the lock after reading VMA2 due to
 936                          * contention, then we get:
 937                          *
 938                          *      last_vma_end = 16k
 939                          *
 940                          * 1) VMA2 is freed, but VMA3 exists:
 941                          *
 942                          *    vma_next(vmi) will return VMA3.
 943                          *    In this case, just continue from VMA3.
 944                          *
 945                          * 2) VMA2 still exists:
 946                          *
 947                          *    vma_next(vmi) will return VMA3.
 948                          *    In this case, just continue from VMA3.
 949                          *
 950                          * 3) No more VMAs can be found:
 951                          *
 952                          *    vma_next(vmi) will return NULL.
 953                          *    No more things to do, just break.
 954                          *
 955                          * 4) (last_vma_end - 1) is the middle of a vma (VMA'):
 956                          *
 957                          *    vma_next(vmi) will return VMA' whose range
 958                          *    contains last_vma_end.
 959                          *    Iterate VMA' from last_vma_end.
 960                          */
 961                         vma = vma_next(&vmi);
 962                         /* Case 3 above */
 963                         if (!vma)
 964                                 break;
 965
 966                         /* Case 1 and 2 above */
 967                         if (vma->vm_start >= last_vma_end)
 968                                 continue;
 969
 970                         /* Case 4 above */
 971                         if (vma->vm_end > last_vma_end)
 972                                 smap_gather_stats(vma, &mss, last_vma_end);
 973                 }
 974         } for_each_vma(vmi, vma);
 975
 976 empty_set:
 977         show_vma_header_prefix(m, vma_start, last_vma_end, 0, 0, 0, 0);
 978         seq_pad(m, ' ');
 979         seq_puts(m, "[rollup]\n");
 980
 981         __show_smap(m, &mss, true);
 982
 983         release_task_mempolicy(priv);
 984         mmap_read_unlock(mm);
 985
 986 out_put_mm:
 987         mmput(mm);
 988 out_put_task:
 989         put_task_struct(priv->task);
 990         priv->task = NULL;
 991
 992         return ret;
 993 }
 994 #undef SEQ_PUT_DEC
 995
 996 static const struct seq_operations proc_pid_smaps_op = {
 997         .start  = m_start,
 998         .next   = m_next,
 999         .stop   = m_stop,
1000         .show   = show_smap
1001 };
1002
1003 static int pid_smaps_open(struct inode *inode, struct file *file)
1004 {
1005         return do_maps_open(inode, file, &proc_pid_smaps_op);
1006 }
1007
1008 static int smaps_rollup_open(struct inode *inode, struct file *file)
1009 {
1010         int ret;
1011         struct proc_maps_private *priv;
1012
1013         priv = kzalloc(sizeof(*priv), GFP_KERNEL_ACCOUNT);
1014         if (!priv)
1015                 return -ENOMEM;
1016
1017         ret = single_open(file, show_smaps_rollup, priv);
1018         if (ret)
1019                 goto out_free;
1020
1021         priv->inode = inode;
1022         priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
1023         if (IS_ERR(priv->mm)) {
1024                 ret = PTR_ERR(priv->mm);
1025
1026                 single_release(inode, file);
1027                 goto out_free;
1028         }
1029
1030         return 0;
1031
1032 out_free:
1033         kfree(priv);
1034         return ret;
1035 }
1036
1037 static int smaps_rollup_release(struct inode *inode, struct file *file)
1038 {
1039         struct seq_file *seq = file->private_data;
1040         struct proc_maps_private *priv = seq->private;
1041
1042         if (priv->mm)
1043                 mmdrop(priv->mm);
1044
1045         kfree(priv);
1046         return single_release(inode, file);
1047 }
1048
1049 const struct file_operations proc_pid_smaps_operations = {
1050         .open           = pid_smaps_open,
1051         .read           = seq_read,
1052         .llseek         = seq_lseek,
1053         .release        = proc_map_release,
1054 };
1055
1056 const struct file_operations proc_pid_smaps_rollup_operations = {
1057         .open           = smaps_rollup_open,
1058         .read           = seq_read,
1059         .llseek         = seq_lseek,
1060         .release        = smaps_rollup_release,
1061 };
1062
1063 enum clear_refs_types {
1064         CLEAR_REFS_ALL = 1,
1065         CLEAR_REFS_ANON,
1066         CLEAR_REFS_MAPPED,
1067         CLEAR_REFS_SOFT_DIRTY,
1068         CLEAR_REFS_MM_HIWATER_RSS,
1069         CLEAR_REFS_LAST,
1070 };
1071
1072 struct clear_refs_private {
1073         enum clear_refs_types type;
1074 };
1075
1076 #ifdef CONFIG_MEM_SOFT_DIRTY
1077
1078 static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
1079 {
1080         struct page *page;
1081
1082         if (!pte_write(pte))
1083                 return false;
1084         if (!is_cow_mapping(vma->vm_flags))
1085                 return false;
1086         if (likely(!test_bit(MMF_HAS_PINNED, &vma->vm_mm->flags)))
1087                 return false;
1088         page = vm_normal_page(vma, addr, pte);
1089         if (!page)
1090                 return false;
1091         return page_maybe_dma_pinned(page);
1092 }
1093
1094 static inline void clear_soft_dirty(struct vm_area_struct *vma,
1095                 unsigned long addr, pte_t *pte)
1096 {
1097         /*
1098          * The soft-dirty tracker uses #PF-s to catch writes
1099          * to pages, so write-protect the pte as well. See the
1100          * Documentation/admin-guide/mm/soft-dirty.rst for full description
1101          * of how soft-dirty works.
1102          */
1103         pte_t ptent = ptep_get(pte);
1104
1105         if (pte_present(ptent)) {
1106                 pte_t old_pte;
1107
1108                 if (pte_is_pinned(vma, addr, ptent))
1109                         return;
1110                 old_pte = ptep_modify_prot_start(vma, addr, pte);
1111                 ptent = pte_wrprotect(old_pte);
1112                 ptent = pte_clear_soft_dirty(ptent);
1113                 ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent);
1114         } else if (is_swap_pte(ptent)) {
1115                 ptent = pte_swp_clear_soft_dirty(ptent);
1116                 set_pte_at(vma->vm_mm, addr, pte, ptent);
1117         }
1118 }
1119 #else
1120 static inline void clear_soft_dirty(struct vm_area_struct *vma,
1121                 unsigned long addr, pte_t *pte)
1122 {
1123 }
1124 #endif
1125
1126 #if defined(CONFIG_MEM_SOFT_DIRTY) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
1127 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
1128                 unsigned long addr, pmd_t *pmdp)
1129 {
1130         pmd_t old, pmd = *pmdp;
1131
1132         if (pmd_present(pmd)) {
1133                 /* See comment in change_huge_pmd() */
1134                 old = pmdp_invalidate(vma, addr, pmdp);
1135                 if (pmd_dirty(old))
1136                         pmd = pmd_mkdirty(pmd);
1137                 if (pmd_young(old))
1138                         pmd = pmd_mkyoung(pmd);
1139
1140                 pmd = pmd_wrprotect(pmd);
1141                 pmd = pmd_clear_soft_dirty(pmd);
1142
1143                 set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
1144         } else if (is_migration_entry(pmd_to_swp_entry(pmd))) {
1145                 pmd = pmd_swp_clear_soft_dirty(pmd);
1146                 set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
1147         }
1148 }
1149 #else
1150 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
1151                 unsigned long addr, pmd_t *pmdp)
1152 {
1153 }
1154 #endif
1155
1156 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
1157                                 unsigned long end, struct mm_walk *walk)
1158 {
1159         struct clear_refs_private *cp = walk->private;
1160         struct vm_area_struct *vma = walk->vma;
1161         pte_t *pte, ptent;
1162         spinlock_t *ptl;
1163         struct page *page;
1164
1165         ptl = pmd_trans_huge_lock(pmd, vma);
1166         if (ptl) {
1167                 if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
1168                         clear_soft_dirty_pmd(vma, addr, pmd);
1169                         goto out;
1170                 }
1171
1172                 if (!pmd_present(*pmd))
1173                         goto out;
1174
1175                 page = pmd_page(*pmd);
1176
1177                 /* Clear accessed and referenced bits. */
1178                 pmdp_test_and_clear_young(vma, addr, pmd);
1179                 test_and_clear_page_young(page);
1180                 ClearPageReferenced(page);
1181 out:
1182                 spin_unlock(ptl);
1183                 return 0;
1184         }
1185
1186         pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
1187         if (!pte) {
1188                 walk->action = ACTION_AGAIN;
1189                 return 0;
1190         }
1191         for (; addr != end; pte++, addr += PAGE_SIZE) {
1192                 ptent = ptep_get(pte);
1193
1194                 if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
1195                         clear_soft_dirty(vma, addr, pte);
1196                         continue;
1197                 }
1198
1199                 if (!pte_present(ptent))
1200                         continue;
1201
1202                 page = vm_normal_page(vma, addr, ptent);
1203                 if (!page)
1204                         continue;
1205
1206                 /* Clear accessed and referenced bits. */
1207                 ptep_test_and_clear_young(vma, addr, pte);
1208                 test_and_clear_page_young(page);
1209                 ClearPageReferenced(page);
1210         }
1211         pte_unmap_unlock(pte - 1, ptl);
1212         cond_resched();
1213         return 0;
1214 }
1215
1216 static int clear_refs_test_walk(unsigned long start, unsigned long end,
1217                                 struct mm_walk *walk)
1218 {
1219         struct clear_refs_private *cp = walk->private;
1220         struct vm_area_struct *vma = walk->vma;
1221
1222         if (vma->vm_flags & VM_PFNMAP)
1223                 return 1;
1224
1225         /*
1226          * Writing 1 to /proc/pid/clear_refs affects all pages.
1227          * Writing 2 to /proc/pid/clear_refs only affects anonymous pages.
1228          * Writing 3 to /proc/pid/clear_refs only affects file mapped pages.
1229          * Writing 4 to /proc/pid/clear_refs affects all pages.
1230          */
1231         if (cp->type == CLEAR_REFS_ANON && vma->vm_file)
1232                 return 1;
1233         if (cp->type == CLEAR_REFS_MAPPED && !vma->vm_file)
1234                 return 1;
1235         return 0;
1236 }
1237
1238 static const struct mm_walk_ops clear_refs_walk_ops = {
1239         .pmd_entry              = clear_refs_pte_range,
1240         .test_walk              = clear_refs_test_walk,
1241         .walk_lock              = PGWALK_WRLOCK,
1242 };
1243
1244 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
1245                                 size_t count, loff_t *ppos)
1246 {
1247         struct task_struct *task;
1248         char buffer[PROC_NUMBUF] = {};
1249         struct mm_struct *mm;
1250         struct vm_area_struct *vma;
1251         enum clear_refs_types type;
1252         int itype;
1253         int rv;
1254
1255         if (count > sizeof(buffer) - 1)
1256                 count = sizeof(buffer) - 1;
1257         if (copy_from_user(buffer, buf, count))
1258                 return -EFAULT;
1259         rv = kstrtoint(strstrip(buffer), 10, &itype);
1260         if (rv < 0)
1261                 return rv;
1262         type = (enum clear_refs_types)itype;
1263         if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
1264                 return -EINVAL;
1265
1266         task = get_proc_task(file_inode(file));
1267         if (!task)
1268                 return -ESRCH;
1269         mm = get_task_mm(task);
1270         if (mm) {
1271                 VMA_ITERATOR(vmi, mm, 0);
1272                 struct mmu_notifier_range range;
1273                 struct clear_refs_private cp = {
1274                         .type = type,
1275                 };
1276
1277                 if (mmap_write_lock_killable(mm)) {
1278                         count = -EINTR;
1279                         goto out_mm;
1280                 }
1281                 if (type == CLEAR_REFS_MM_HIWATER_RSS) {
1282                         /*
1283                          * Writing 5 to /proc/pid/clear_refs resets the peak
1284                          * resident set size to this mm's current rss value.
1285                          */
1286                         reset_mm_hiwater_rss(mm);
1287                         goto out_unlock;
1288                 }
1289
1290                 if (type == CLEAR_REFS_SOFT_DIRTY) {
1291                         for_each_vma(vmi, vma) {
1292                                 if (!(vma->vm_flags & VM_SOFTDIRTY))
1293                                         continue;
1294                                 vm_flags_clear(vma, VM_SOFTDIRTY);
1295                                 vma_set_page_prot(vma);
1296                         }
1297
1298                         inc_tlb_flush_pending(mm);
1299                         mmu_notifier_range_init(&range, MMU_NOTIFY_SOFT_DIRTY,
1300                                                 0, mm, 0, -1UL);
1301                         mmu_notifier_invalidate_range_start(&range);
1302                 }
1303                 walk_page_range(mm, 0, -1, &clear_refs_walk_ops, &cp);
1304                 if (type == CLEAR_REFS_SOFT_DIRTY) {
1305                         mmu_notifier_invalidate_range_end(&range);
1306                         flush_tlb_mm(mm);
1307                         dec_tlb_flush_pending(mm);
1308                 }
1309 out_unlock:
1310                 mmap_write_unlock(mm);
1311 out_mm:
1312                 mmput(mm);
1313         }
1314         put_task_struct(task);
1315
1316         return count;
1317 }
1318
1319 const struct file_operations proc_clear_refs_operations = {
1320         .write          = clear_refs_write,
1321         .llseek         = noop_llseek,
1322 };
1323
1324 typedef struct {
1325         u64 pme;
1326 } pagemap_entry_t;
1327
1328 struct pagemapread {
1329         int pos, len;           /* units: PM_ENTRY_BYTES, not bytes */
1330         pagemap_entry_t *buffer;
1331         bool show_pfn;
1332 };
1333
1334 #define PAGEMAP_WALK_SIZE       (PMD_SIZE)
1335 #define PAGEMAP_WALK_MASK       (PMD_MASK)
1336
1337 #define PM_ENTRY_BYTES          sizeof(pagemap_entry_t)
1338 #define PM_PFRAME_BITS          55
1339 #define PM_PFRAME_MASK          GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
1340 #define PM_SOFT_DIRTY           BIT_ULL(55)
1341 #define PM_MMAP_EXCLUSIVE       BIT_ULL(56)
1342 #define PM_UFFD_WP              BIT_ULL(57)
1343 #define PM_FILE                 BIT_ULL(61)
1344 #define PM_SWAP                 BIT_ULL(62)
1345 #define PM_PRESENT              BIT_ULL(63)
1346
1347 #define PM_END_OF_BUFFER    1
1348
1349 static inline pagemap_entry_t make_pme(u64 frame, u64 flags)
1350 {
1351         return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags };
1352 }
1353
1354 static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,
1355                           struct pagemapread *pm)
1356 {
1357         pm->buffer[pm->pos++] = *pme;
1358         if (pm->pos >= pm->len)
1359                 return PM_END_OF_BUFFER;
1360         return 0;
1361 }
1362
1363 static int pagemap_pte_hole(unsigned long start, unsigned long end,
1364                             __always_unused int depth, struct mm_walk *walk)
1365 {
1366         struct pagemapread *pm = walk->private;
1367         unsigned long addr = start;
1368         int err = 0;
1369
1370         while (addr < end) {
1371                 struct vm_area_struct *vma = find_vma(walk->mm, addr);
1372                 pagemap_entry_t pme = make_pme(0, 0);
1373                 /* End of address space hole, which we mark as non-present. */
1374                 unsigned long hole_end;
1375
1376                 if (vma)
1377                         hole_end = min(end, vma->vm_start);
1378                 else
1379                         hole_end = end;
1380
1381                 for (; addr < hole_end; addr += PAGE_SIZE) {
1382                         err = add_to_pagemap(addr, &pme, pm);
1383                         if (err)
1384                                 goto out;
1385                 }
1386
1387                 if (!vma)
1388                         break;
1389
1390                 /* Addresses in the VMA. */
1391                 if (vma->vm_flags & VM_SOFTDIRTY)
1392                         pme = make_pme(0, PM_SOFT_DIRTY);
1393                 for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
1394                         err = add_to_pagemap(addr, &pme, pm);
1395                         if (err)
1396                                 goto out;
1397                 }
1398         }
1399 out:
1400         return err;
1401 }
1402
1403 static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
1404                 struct vm_area_struct *vma, unsigned long addr, pte_t pte)
1405 {
1406         u64 frame = 0, flags = 0;
1407         struct page *page = NULL;
1408         bool migration = false;
1409
1410         if (pte_present(pte)) {
1411                 if (pm->show_pfn)
1412                         frame = pte_pfn(pte);
1413                 flags |= PM_PRESENT;
1414                 page = vm_normal_page(vma, addr, pte);
1415                 if (pte_soft_dirty(pte))
1416                         flags |= PM_SOFT_DIRTY;
1417                 if (pte_uffd_wp(pte))
1418                         flags |= PM_UFFD_WP;
1419         } else if (is_swap_pte(pte)) {
1420                 swp_entry_t entry;
1421                 if (pte_swp_soft_dirty(pte))
1422                         flags |= PM_SOFT_DIRTY;
1423                 if (pte_swp_uffd_wp(pte))
1424                         flags |= PM_UFFD_WP;
1425                 entry = pte_to_swp_entry(pte);
1426                 if (pm->show_pfn) {
1427                         pgoff_t offset;
1428                         /*
1429                          * For PFN swap offsets, keeping the offset field
1430                          * to be PFN only to be compatible with old smaps.
1431                          */
1432                         if (is_pfn_swap_entry(entry))
1433                                 offset = swp_offset_pfn(entry);
1434                         else
1435                                 offset = swp_offset(entry);
1436                         frame = swp_type(entry) |
1437                             (offset << MAX_SWAPFILES_SHIFT);
1438                 }
1439                 flags |= PM_SWAP;
1440                 migration = is_migration_entry(entry);
1441                 if (is_pfn_swap_entry(entry))
1442                         page = pfn_swap_entry_to_page(entry);
1443                 if (pte_marker_entry_uffd_wp(entry))
1444                         flags |= PM_UFFD_WP;
1445         }
1446
1447         if (page && !PageAnon(page))
1448                 flags |= PM_FILE;
1449         if (page && !migration && page_mapcount(page) == 1)
1450                 flags |= PM_MMAP_EXCLUSIVE;
1451         if (vma->vm_flags & VM_SOFTDIRTY)
1452                 flags |= PM_SOFT_DIRTY;
1453
1454         return make_pme(frame, flags);
1455 }
1456
1457 static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
1458                              struct mm_walk *walk)
1459 {
1460         struct vm_area_struct *vma = walk->vma;
1461         struct pagemapread *pm = walk->private;
1462         spinlock_t *ptl;
1463         pte_t *pte, *orig_pte;
1464         int err = 0;
1465 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1466         bool migration = false;
1467
1468         ptl = pmd_trans_huge_lock(pmdp, vma);
1469         if (ptl) {
1470                 u64 flags = 0, frame = 0;
1471                 pmd_t pmd = *pmdp;
1472                 struct page *page = NULL;
1473
1474                 if (vma->vm_flags & VM_SOFTDIRTY)
1475                         flags |= PM_SOFT_DIRTY;
1476
1477                 if (pmd_present(pmd)) {
1478                         page = pmd_page(pmd);
1479
1480                         flags |= PM_PRESENT;
1481                         if (pmd_soft_dirty(pmd))
1482                                 flags |= PM_SOFT_DIRTY;
1483                         if (pmd_uffd_wp(pmd))
1484                                 flags |= PM_UFFD_WP;
1485                         if (pm->show_pfn)
1486                                 frame = pmd_pfn(pmd) +
1487                                         ((addr & ~PMD_MASK) >> PAGE_SHIFT);
1488                 }
1489 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
1490                 else if (is_swap_pmd(pmd)) {
1491                         swp_entry_t entry = pmd_to_swp_entry(pmd);
1492                         unsigned long offset;
1493
1494                         if (pm->show_pfn) {
1495                                 if (is_pfn_swap_entry(entry))
1496                                         offset = swp_offset_pfn(entry);
1497                                 else
1498                                         offset = swp_offset(entry);
1499                                 offset = offset +
1500                                         ((addr & ~PMD_MASK) >> PAGE_SHIFT);
1501                                 frame = swp_type(entry) |
1502                                         (offset << MAX_SWAPFILES_SHIFT);
1503                         }
1504                         flags |= PM_SWAP;
1505                         if (pmd_swp_soft_dirty(pmd))
1506                                 flags |= PM_SOFT_DIRTY;
1507                         if (pmd_swp_uffd_wp(pmd))
1508                                 flags |= PM_UFFD_WP;
1509                         VM_BUG_ON(!is_pmd_migration_entry(pmd));
1510                         migration = is_migration_entry(entry);
1511                         page = pfn_swap_entry_to_page(entry);
1512                 }
1513 #endif
1514
1515                 if (page && !migration && page_mapcount(page) == 1)
1516                         flags |= PM_MMAP_EXCLUSIVE;
1517
1518                 for (; addr != end; addr += PAGE_SIZE) {
1519                         pagemap_entry_t pme = make_pme(frame, flags);
1520
1521                         err = add_to_pagemap(addr, &pme, pm);
1522                         if (err)
1523                                 break;
1524                         if (pm->show_pfn) {
1525                                 if (flags & PM_PRESENT)
1526                                         frame++;
1527                                 else if (flags & PM_SWAP)
1528                                         frame += (1 << MAX_SWAPFILES_SHIFT);
1529                         }
1530                 }
1531                 spin_unlock(ptl);
1532                 return err;
1533         }
1534 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1535
1536         /*
1537          * We can assume that @vma always points to a valid one and @end never
1538          * goes beyond vma->vm_end.
1539          */
1540         orig_pte = pte = pte_offset_map_lock(walk->mm, pmdp, addr, &ptl);
1541         if (!pte) {
1542                 walk->action = ACTION_AGAIN;
1543                 return err;
1544         }
1545         for (; addr < end; pte++, addr += PAGE_SIZE) {
1546                 pagemap_entry_t pme;
1547
1548                 pme = pte_to_pagemap_entry(pm, vma, addr, ptep_get(pte));
1549                 err = add_to_pagemap(addr, &pme, pm);
1550                 if (err)
1551                         break;
1552         }
1553         pte_unmap_unlock(orig_pte, ptl);
1554
1555         cond_resched();
1556
1557         return err;
1558 }
1559
1560 #ifdef CONFIG_HUGETLB_PAGE
1561 /* This function walks within one hugetlb entry in the single call */
1562 static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
1563                                  unsigned long addr, unsigned long end,
1564                                  struct mm_walk *walk)
1565 {
1566         struct pagemapread *pm = walk->private;
1567         struct vm_area_struct *vma = walk->vma;
1568         u64 flags = 0, frame = 0;
1569         int err = 0;
1570         pte_t pte;
1571
1572         if (vma->vm_flags & VM_SOFTDIRTY)
1573                 flags |= PM_SOFT_DIRTY;
1574
1575         pte = huge_ptep_get(ptep);
1576         if (pte_present(pte)) {
1577                 struct page *page = pte_page(pte);
1578
1579                 if (!PageAnon(page))
1580                         flags |= PM_FILE;
1581
1582                 if (page_mapcount(page) == 1)
1583                         flags |= PM_MMAP_EXCLUSIVE;
1584
1585                 if (huge_pte_uffd_wp(pte))
1586                         flags |= PM_UFFD_WP;
1587
1588                 flags |= PM_PRESENT;
1589                 if (pm->show_pfn)
1590                         frame = pte_pfn(pte) +
1591                                 ((addr & ~hmask) >> PAGE_SHIFT);
1592         } else if (pte_swp_uffd_wp_any(pte)) {
1593                 flags |= PM_UFFD_WP;
1594         }
1595
1596         for (; addr != end; addr += PAGE_SIZE) {
1597                 pagemap_entry_t pme = make_pme(frame, flags);
1598
1599                 err = add_to_pagemap(addr, &pme, pm);
1600                 if (err)
1601                         return err;
1602                 if (pm->show_pfn && (flags & PM_PRESENT))
1603                         frame++;
1604         }
1605
1606         cond_resched();
1607
1608         return err;
1609 }
1610 #else
1611 #define pagemap_hugetlb_range   NULL
1612 #endif /* HUGETLB_PAGE */
1613
1614 static const struct mm_walk_ops pagemap_ops = {
1615         .pmd_entry      = pagemap_pmd_range,
1616         .pte_hole       = pagemap_pte_hole,
1617         .hugetlb_entry  = pagemap_hugetlb_range,
1618         .walk_lock      = PGWALK_RDLOCK,
1619 };
1620
1621 /*
1622  * /proc/pid/pagemap - an array mapping virtual pages to pfns
1623  *
1624  * For each page in the address space, this file contains one 64-bit entry
1625  * consisting of the following:
1626  *
1627  * Bits 0-54  page frame number (PFN) if present
1628  * Bits 0-4   swap type if swapped
1629  * Bits 5-54  swap offset if swapped
1630  * Bit  55    pte is soft-dirty (see Documentation/admin-guide/mm/soft-dirty.rst)
1631  * Bit  56    page exclusively mapped
1632  * Bit  57    pte is uffd-wp write-protected
1633  * Bits 58-60 zero
1634  * Bit  61    page is file-page or shared-anon
1635  * Bit  62    page swapped
1636  * Bit  63    page present
1637  *
1638  * If the page is not present but in swap, then the PFN contains an
1639  * encoding of the swap file number and the page's offset into the
1640  * swap. Unmapped pages return a null PFN. This allows determining
1641  * precisely which pages are mapped (or in swap) and comparing mapped
1642  * pages between processes.
1643  *
1644  * Efficient users of this interface will use /proc/pid/maps to
1645  * determine which areas of memory are actually mapped and llseek to
1646  * skip over unmapped regions.
1647  */
1648 static ssize_t pagemap_read(struct file *file, char __user *buf,
1649                             size_t count, loff_t *ppos)
1650 {
1651         struct mm_struct *mm = file->private_data;
1652         struct pagemapread pm;
1653         unsigned long src;
1654         unsigned long svpfn;
1655         unsigned long start_vaddr;
1656         unsigned long end_vaddr;
1657         int ret = 0, copied = 0;
1658
1659         if (!mm || !mmget_not_zero(mm))
1660                 goto out;
1661
1662         ret = -EINVAL;
1663         /* file position must be aligned */
1664         if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES))
1665                 goto out_mm;
1666
1667         ret = 0;
1668         if (!count)
1669                 goto out_mm;
1670
1671         /* do not disclose physical addresses: attack vector */
1672         pm.show_pfn = file_ns_capable(file, &init_user_ns, CAP_SYS_ADMIN);
1673
1674         pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
1675         pm.buffer = kmalloc_array(pm.len, PM_ENTRY_BYTES, GFP_KERNEL);
1676         ret = -ENOMEM;
1677         if (!pm.buffer)
1678                 goto out_mm;
1679
1680         src = *ppos;
1681         svpfn = src / PM_ENTRY_BYTES;
1682         end_vaddr = mm->task_size;
1683
1684         /* watch out for wraparound */
1685         start_vaddr = end_vaddr;
1686         if (svpfn <= (ULONG_MAX >> PAGE_SHIFT)) {
1687                 unsigned long end;
1688
1689                 ret = mmap_read_lock_killable(mm);
1690                 if (ret)
1691                         goto out_free;
1692                 start_vaddr = untagged_addr_remote(mm, svpfn << PAGE_SHIFT);
1693                 mmap_read_unlock(mm);
1694
1695                 end = start_vaddr + ((count / PM_ENTRY_BYTES) << PAGE_SHIFT);
1696                 if (end >= start_vaddr && end < mm->task_size)
1697                         end_vaddr = end;
1698         }
1699
1700         /* Ensure the address is inside the task */
1701         if (start_vaddr > mm->task_size)
1702                 start_vaddr = end_vaddr;
1703
1704         ret = 0;
1705         while (count && (start_vaddr < end_vaddr)) {
1706                 int len;
1707                 unsigned long end;
1708
1709                 pm.pos = 0;
1710                 end = (start_vaddr + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
1711                 /* overflow ? */
1712                 if (end < start_vaddr || end > end_vaddr)
1713                         end = end_vaddr;
1714                 ret = mmap_read_lock_killable(mm);
1715                 if (ret)
1716                         goto out_free;
1717                 ret = walk_page_range(mm, start_vaddr, end, &pagemap_ops, &pm);
1718                 mmap_read_unlock(mm);
1719                 start_vaddr = end;
1720
1721                 len = min(count, PM_ENTRY_BYTES * pm.pos);
1722                 if (copy_to_user(buf, pm.buffer, len)) {
1723                         ret = -EFAULT;
1724                         goto out_free;
1725                 }
1726                 copied += len;
1727                 buf += len;
1728                 count -= len;
1729         }
1730         *ppos += copied;
1731         if (!ret || ret == PM_END_OF_BUFFER)
1732                 ret = copied;
1733
1734 out_free:
1735         kfree(pm.buffer);
1736 out_mm:
1737         mmput(mm);
1738 out:
1739         return ret;
1740 }
1741
1742 static int pagemap_open(struct inode *inode, struct file *file)
1743 {
1744         struct mm_struct *mm;
1745
1746         mm = proc_mem_open(inode, PTRACE_MODE_READ);
1747         if (IS_ERR(mm))
1748                 return PTR_ERR(mm);
1749         file->private_data = mm;
1750         return 0;
1751 }
1752
1753 static int pagemap_release(struct inode *inode, struct file *file)
1754 {
1755         struct mm_struct *mm = file->private_data;
1756
1757         if (mm)
1758                 mmdrop(mm);
1759         return 0;
1760 }
1761
1762 #define PM_SCAN_CATEGORIES      (PAGE_IS_WPALLOWED | PAGE_IS_WRITTEN |  \
1763                                  PAGE_IS_FILE | PAGE_IS_PRESENT |       \
1764                                  PAGE_IS_SWAPPED | PAGE_IS_PFNZERO |    \
1765                                  PAGE_IS_HUGE)
1766 #define PM_SCAN_FLAGS           (PM_SCAN_WP_MATCHING | PM_SCAN_CHECK_WPASYNC)
1767
1768 struct pagemap_scan_private {
1769         struct pm_scan_arg arg;
1770         unsigned long masks_of_interest, cur_vma_category;
1771         struct page_region *vec_buf;
1772         unsigned long vec_buf_len, vec_buf_index, found_pages;
1773         struct page_region __user *vec_out;
1774 };
1775
1776 static unsigned long pagemap_page_category(struct pagemap_scan_private *p,
1777                                            struct vm_area_struct *vma,
1778                                            unsigned long addr, pte_t pte)
1779 {
1780         unsigned long categories = 0;
1781
1782         if (pte_present(pte)) {
1783                 struct page *page;
1784
1785                 categories |= PAGE_IS_PRESENT;
1786                 if (!pte_uffd_wp(pte))
1787                         categories |= PAGE_IS_WRITTEN;
1788
1789                 if (p->masks_of_interest & PAGE_IS_FILE) {
1790                         page = vm_normal_page(vma, addr, pte);
1791                         if (page && !PageAnon(page))
1792                                 categories |= PAGE_IS_FILE;
1793                 }
1794
1795                 if (is_zero_pfn(pte_pfn(pte)))
1796                         categories |= PAGE_IS_PFNZERO;
1797         } else if (is_swap_pte(pte)) {
1798                 swp_entry_t swp;
1799
1800                 categories |= PAGE_IS_SWAPPED;
1801                 if (!pte_swp_uffd_wp_any(pte))
1802                         categories |= PAGE_IS_WRITTEN;
1803
1804                 if (p->masks_of_interest & PAGE_IS_FILE) {
1805                         swp = pte_to_swp_entry(pte);
1806                         if (is_pfn_swap_entry(swp) &&
1807                             !PageAnon(pfn_swap_entry_to_page(swp)))
1808                                 categories |= PAGE_IS_FILE;
1809                 }
1810         }
1811
1812         return categories;
1813 }
1814
1815 static void make_uffd_wp_pte(struct vm_area_struct *vma,
1816                              unsigned long addr, pte_t *pte)
1817 {
1818         pte_t ptent = ptep_get(pte);
1819
1820         if (pte_present(ptent)) {
1821                 pte_t old_pte;
1822
1823                 old_pte = ptep_modify_prot_start(vma, addr, pte);
1824                 ptent = pte_mkuffd_wp(ptent);
1825                 ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent);
1826         } else if (is_swap_pte(ptent)) {
1827                 ptent = pte_swp_mkuffd_wp(ptent);
1828                 set_pte_at(vma->vm_mm, addr, pte, ptent);
1829         } else {
1830                 set_pte_at(vma->vm_mm, addr, pte,
1831                            make_pte_marker(PTE_MARKER_UFFD_WP));
1832         }
1833 }
1834
1835 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1836 static unsigned long pagemap_thp_category(struct pagemap_scan_private *p,
1837                                           struct vm_area_struct *vma,
1838                                           unsigned long addr, pmd_t pmd)
1839 {
1840         unsigned long categories = PAGE_IS_HUGE;
1841
1842         if (pmd_present(pmd)) {
1843                 struct page *page;
1844
1845                 categories |= PAGE_IS_PRESENT;
1846                 if (!pmd_uffd_wp(pmd))
1847                         categories |= PAGE_IS_WRITTEN;
1848
1849                 if (p->masks_of_interest & PAGE_IS_FILE) {
1850                         page = vm_normal_page_pmd(vma, addr, pmd);
1851                         if (page && !PageAnon(page))
1852                                 categories |= PAGE_IS_FILE;
1853                 }
1854
1855                 if (is_zero_pfn(pmd_pfn(pmd)))
1856                         categories |= PAGE_IS_PFNZERO;
1857         } else if (is_swap_pmd(pmd)) {
1858                 swp_entry_t swp;
1859
1860                 categories |= PAGE_IS_SWAPPED;
1861                 if (!pmd_swp_uffd_wp(pmd))
1862                         categories |= PAGE_IS_WRITTEN;
1863
1864                 if (p->masks_of_interest & PAGE_IS_FILE) {
1865                         swp = pmd_to_swp_entry(pmd);
1866                         if (is_pfn_swap_entry(swp) &&
1867                             !PageAnon(pfn_swap_entry_to_page(swp)))
1868                                 categories |= PAGE_IS_FILE;
1869                 }
1870         }
1871
1872         return categories;
1873 }
1874
1875 static void make_uffd_wp_pmd(struct vm_area_struct *vma,
1876                              unsigned long addr, pmd_t *pmdp)
1877 {
1878         pmd_t old, pmd = *pmdp;
1879
1880         if (pmd_present(pmd)) {
1881                 old = pmdp_invalidate_ad(vma, addr, pmdp);
1882                 pmd = pmd_mkuffd_wp(old);
1883                 set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
1884         } else if (is_migration_entry(pmd_to_swp_entry(pmd))) {
1885                 pmd = pmd_swp_mkuffd_wp(pmd);
1886                 set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
1887         }
1888 }
1889 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1890
1891 #ifdef CONFIG_HUGETLB_PAGE
1892 static unsigned long pagemap_hugetlb_category(pte_t pte)
1893 {
1894         unsigned long categories = PAGE_IS_HUGE;
1895
1896         /*
1897          * According to pagemap_hugetlb_range(), file-backed HugeTLB
1898          * page cannot be swapped. So PAGE_IS_FILE is not checked for
1899          * swapped pages.
1900          */
1901         if (pte_present(pte)) {
1902                 categories |= PAGE_IS_PRESENT;
1903                 if (!huge_pte_uffd_wp(pte))
1904                         categories |= PAGE_IS_WRITTEN;
1905                 if (!PageAnon(pte_page(pte)))
1906                         categories |= PAGE_IS_FILE;
1907                 if (is_zero_pfn(pte_pfn(pte)))
1908                         categories |= PAGE_IS_PFNZERO;
1909         } else if (is_swap_pte(pte)) {
1910                 categories |= PAGE_IS_SWAPPED;
1911                 if (!pte_swp_uffd_wp_any(pte))
1912                         categories |= PAGE_IS_WRITTEN;
1913         }
1914
1915         return categories;
1916 }
1917
1918 static void make_uffd_wp_huge_pte(struct vm_area_struct *vma,
1919                                   unsigned long addr, pte_t *ptep,
1920                                   pte_t ptent)
1921 {
1922         unsigned long psize;
1923
1924         if (is_hugetlb_entry_hwpoisoned(ptent) || is_pte_marker(ptent))
1925                 return;
1926
1927         psize = huge_page_size(hstate_vma(vma));
1928
1929         if (is_hugetlb_entry_migration(ptent))
1930                 set_huge_pte_at(vma->vm_mm, addr, ptep,
1931                                 pte_swp_mkuffd_wp(ptent), psize);
1932         else if (!huge_pte_none(ptent))
1933                 huge_ptep_modify_prot_commit(vma, addr, ptep, ptent,
1934                                              huge_pte_mkuffd_wp(ptent));
1935         else
1936                 set_huge_pte_at(vma->vm_mm, addr, ptep,
1937                                 make_pte_marker(PTE_MARKER_UFFD_WP), psize);
1938 }
1939 #endif /* CONFIG_HUGETLB_PAGE */
1940
1941 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLB_PAGE)
1942 static void pagemap_scan_backout_range(struct pagemap_scan_private *p,
1943                                        unsigned long addr, unsigned long end)
1944 {
1945         struct page_region *cur_buf = &p->vec_buf[p->vec_buf_index];
1946
1947         if (cur_buf->start != addr)
1948                 cur_buf->end = addr;
1949         else
1950                 cur_buf->start = cur_buf->end = 0;
1951
1952         p->found_pages -= (end - addr) / PAGE_SIZE;
1953 }
1954 #endif
1955
1956 static bool pagemap_scan_is_interesting_page(unsigned long categories,
1957                                              const struct pagemap_scan_private *p)
1958 {
1959         categories ^= p->arg.category_inverted;
1960         if ((categories & p->arg.category_mask) != p->arg.category_mask)
1961                 return false;
1962         if (p->arg.category_anyof_mask && !(categories & p->arg.category_anyof_mask))
1963                 return false;
1964
1965         return true;
1966 }
1967
1968 static bool pagemap_scan_is_interesting_vma(unsigned long categories,
1969                                             const struct pagemap_scan_private *p)
1970 {
1971         unsigned long required = p->arg.category_mask & PAGE_IS_WPALLOWED;
1972
1973         categories ^= p->arg.category_inverted;
1974         if ((categories & required) != required)
1975                 return false;
1976
1977         return true;
1978 }
1979
1980 static int pagemap_scan_test_walk(unsigned long start, unsigned long end,
1981                                   struct mm_walk *walk)
1982 {
1983         struct pagemap_scan_private *p = walk->private;
1984         struct vm_area_struct *vma = walk->vma;
1985         unsigned long vma_category = 0;
1986         bool wp_allowed = userfaultfd_wp_async(vma) &&
1987             userfaultfd_wp_use_markers(vma);
1988
1989         if (!wp_allowed) {
1990                 /* User requested explicit failure over wp-async capability */
1991                 if (p->arg.flags & PM_SCAN_CHECK_WPASYNC)
1992                         return -EPERM;
1993                 /*
1994                  * User requires wr-protect, and allows silently skipping
1995                  * unsupported vmas.
1996                  */
1997                 if (p->arg.flags & PM_SCAN_WP_MATCHING)
1998                         return 1;
1999                 /*
2000                  * Then the request doesn't involve wr-protects at all,
2001                  * fall through to the rest checks, and allow vma walk.
2002                  */
2003         }
2004
2005         if (vma->vm_flags & VM_PFNMAP)
2006                 return 1;
2007
2008         if (wp_allowed)
2009                 vma_category |= PAGE_IS_WPALLOWED;
2010
2011         if (!pagemap_scan_is_interesting_vma(vma_category, p))
2012                 return 1;
2013
2014         p->cur_vma_category = vma_category;
2015
2016         return 0;
2017 }
2018
2019 static bool pagemap_scan_push_range(unsigned long categories,
2020                                     struct pagemap_scan_private *p,
2021                                     unsigned long addr, unsigned long end)
2022 {
2023         struct page_region *cur_buf = &p->vec_buf[p->vec_buf_index];
2024
2025         /*
2026          * When there is no output buffer provided at all, the sentinel values
2027          * won't match here. There is no other way for `cur_buf->end` to be
2028          * non-zero other than it being non-empty.
2029          */
2030         if (addr == cur_buf->end && categories == cur_buf->categories) {
2031                 cur_buf->end = end;
2032                 return true;
2033         }
2034
2035         if (cur_buf->end) {
2036                 if (p->vec_buf_index >= p->vec_buf_len - 1)
2037                         return false;
2038
2039                 cur_buf = &p->vec_buf[++p->vec_buf_index];
2040         }
2041
2042         cur_buf->start = addr;
2043         cur_buf->end = end;
2044         cur_buf->categories = categories;
2045
2046         return true;
2047 }
2048
2049 static int pagemap_scan_output(unsigned long categories,
2050                                struct pagemap_scan_private *p,
2051                                unsigned long addr, unsigned long *end)
2052 {
2053         unsigned long n_pages, total_pages;
2054         int ret = 0;
2055
2056         if (!p->vec_buf)
2057                 return 0;
2058
2059         categories &= p->arg.return_mask;
2060
2061         n_pages = (*end - addr) / PAGE_SIZE;
2062         if (check_add_overflow(p->found_pages, n_pages, &total_pages) ||
2063             total_pages > p->arg.max_pages) {
2064                 size_t n_too_much = total_pages - p->arg.max_pages;
2065                 *end -= n_too_much * PAGE_SIZE;
2066                 n_pages -= n_too_much;
2067                 ret = -ENOSPC;
2068         }
2069
2070         if (!pagemap_scan_push_range(categories, p, addr, *end)) {
2071                 *end = addr;
2072                 n_pages = 0;
2073                 ret = -ENOSPC;
2074         }
2075
2076         p->found_pages += n_pages;
2077         if (ret)
2078                 p->arg.walk_end = *end;
2079
2080         return ret;
2081 }
2082
2083 static int pagemap_scan_thp_entry(pmd_t *pmd, unsigned long start,
2084                                   unsigned long end, struct mm_walk *walk)
2085 {
2086 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2087         struct pagemap_scan_private *p = walk->private;
2088         struct vm_area_struct *vma = walk->vma;
2089         unsigned long categories;
2090         spinlock_t *ptl;
2091         int ret = 0;
2092
2093         ptl = pmd_trans_huge_lock(pmd, vma);
2094         if (!ptl)
2095                 return -ENOENT;
2096
2097         categories = p->cur_vma_category |
2098                      pagemap_thp_category(p, vma, start, *pmd);
2099
2100         if (!pagemap_scan_is_interesting_page(categories, p))
2101                 goto out_unlock;
2102
2103         ret = pagemap_scan_output(categories, p, start, &end);
2104         if (start == end)
2105                 goto out_unlock;
2106
2107         if (~p->arg.flags & PM_SCAN_WP_MATCHING)
2108                 goto out_unlock;
2109         if (~categories & PAGE_IS_WRITTEN)
2110                 goto out_unlock;
2111
2112         /*
2113          * Break huge page into small pages if the WP operation
2114          * needs to be performed on a portion of the huge page.
2115          */
2116         if (end != start + HPAGE_SIZE) {
2117                 spin_unlock(ptl);
2118                 split_huge_pmd(vma, pmd, start);
2119                 pagemap_scan_backout_range(p, start, end);
2120                 /* Report as if there was no THP */
2121                 return -ENOENT;
2122         }
2123
2124         make_uffd_wp_pmd(vma, start, pmd);
2125         flush_tlb_range(vma, start, end);
2126 out_unlock:
2127         spin_unlock(ptl);
2128         return ret;
2129 #else /* !CONFIG_TRANSPARENT_HUGEPAGE */
2130         return -ENOENT;
2131 #endif
2132 }
2133
2134 static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start,
2135                                   unsigned long end, struct mm_walk *walk)
2136 {
2137         struct pagemap_scan_private *p = walk->private;
2138         struct vm_area_struct *vma = walk->vma;
2139         unsigned long addr, flush_end = 0;
2140         pte_t *pte, *start_pte;
2141         spinlock_t *ptl;
2142         int ret;
2143
2144         arch_enter_lazy_mmu_mode();
2145
2146         ret = pagemap_scan_thp_entry(pmd, start, end, walk);
2147         if (ret != -ENOENT) {
2148                 arch_leave_lazy_mmu_mode();
2149                 return ret;
2150         }
2151
2152         ret = 0;
2153         start_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl);
2154         if (!pte) {
2155                 arch_leave_lazy_mmu_mode();
2156                 walk->action = ACTION_AGAIN;
2157                 return 0;
2158         }
2159
2160         if ((p->arg.flags & PM_SCAN_WP_MATCHING) && !p->vec_out) {
2161                 /* Fast path for performing exclusive WP */
2162                 for (addr = start; addr != end; pte++, addr += PAGE_SIZE) {
2163                         if (pte_uffd_wp(ptep_get(pte)))
2164                                 continue;
2165                         make_uffd_wp_pte(vma, addr, pte);
2166                         if (!flush_end)
2167                                 start = addr;
2168                         flush_end = addr + PAGE_SIZE;
2169                 }
2170                 goto flush_and_return;
2171         }
2172
2173         if (!p->arg.category_anyof_mask && !p->arg.category_inverted &&
2174             p->arg.category_mask == PAGE_IS_WRITTEN &&
2175             p->arg.return_mask == PAGE_IS_WRITTEN) {
2176                 for (addr = start; addr < end; pte++, addr += PAGE_SIZE) {
2177                         unsigned long next = addr + PAGE_SIZE;
2178
2179                         if (pte_uffd_wp(ptep_get(pte)))
2180                                 continue;
2181                         ret = pagemap_scan_output(p->cur_vma_category | PAGE_IS_WRITTEN,
2182                                                   p, addr, &next);
2183                         if (next == addr)
2184                                 break;
2185                         if (~p->arg.flags & PM_SCAN_WP_MATCHING)
2186                                 continue;
2187                         make_uffd_wp_pte(vma, addr, pte);
2188                         if (!flush_end)
2189                                 start = addr;
2190                         flush_end = next;
2191                 }
2192                 goto flush_and_return;
2193         }
2194
2195         for (addr = start; addr != end; pte++, addr += PAGE_SIZE) {
2196                 unsigned long categories = p->cur_vma_category |
2197                                            pagemap_page_category(p, vma, addr, ptep_get(pte));
2198                 unsigned long next = addr + PAGE_SIZE;
2199
2200                 if (!pagemap_scan_is_interesting_page(categories, p))
2201                         continue;
2202
2203                 ret = pagemap_scan_output(categories, p, addr, &next);
2204                 if (next == addr)
2205                         break;
2206
2207                 if (~p->arg.flags & PM_SCAN_WP_MATCHING)
2208                         continue;
2209                 if (~categories & PAGE_IS_WRITTEN)
2210                         continue;
2211
2212                 make_uffd_wp_pte(vma, addr, pte);
2213                 if (!flush_end)
2214                         start = addr;
2215                 flush_end = next;
2216         }
2217
2218 flush_and_return:
2219         if (flush_end)
2220                 flush_tlb_range(vma, start, addr);
2221
2222         pte_unmap_unlock(start_pte, ptl);
2223         arch_leave_lazy_mmu_mode();
2224
2225         cond_resched();
2226         return ret;
2227 }
2228
2229 #ifdef CONFIG_HUGETLB_PAGE
2230 static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask,
2231                                       unsigned long start, unsigned long end,
2232                                       struct mm_walk *walk)
2233 {
2234         struct pagemap_scan_private *p = walk->private;
2235         struct vm_area_struct *vma = walk->vma;
2236         unsigned long categories;
2237         spinlock_t *ptl;
2238         int ret = 0;
2239         pte_t pte;
2240
2241         if (~p->arg.flags & PM_SCAN_WP_MATCHING) {
2242                 /* Go the short route when not write-protecting pages. */
2243
2244                 pte = huge_ptep_get(ptep);
2245                 categories = p->cur_vma_category | pagemap_hugetlb_category(pte);
2246
2247                 if (!pagemap_scan_is_interesting_page(categories, p))
2248                         return 0;
2249
2250                 return pagemap_scan_output(categories, p, start, &end);
2251         }
2252
2253         i_mmap_lock_write(vma->vm_file->f_mapping);
2254         ptl = huge_pte_lock(hstate_vma(vma), vma->vm_mm, ptep);
2255
2256         pte = huge_ptep_get(ptep);
2257         categories = p->cur_vma_category | pagemap_hugetlb_category(pte);
2258
2259         if (!pagemap_scan_is_interesting_page(categories, p))
2260                 goto out_unlock;
2261
2262         ret = pagemap_scan_output(categories, p, start, &end);
2263         if (start == end)
2264                 goto out_unlock;
2265
2266         if (~categories & PAGE_IS_WRITTEN)
2267                 goto out_unlock;
2268
2269         if (end != start + HPAGE_SIZE) {
2270                 /* Partial HugeTLB page WP isn't possible. */
2271                 pagemap_scan_backout_range(p, start, end);
2272                 p->arg.walk_end = start;
2273                 ret = 0;
2274                 goto out_unlock;
2275         }
2276
2277         make_uffd_wp_huge_pte(vma, start, ptep, pte);
2278         flush_hugetlb_tlb_range(vma, start, end);
2279
2280 out_unlock:
2281         spin_unlock(ptl);
2282         i_mmap_unlock_write(vma->vm_file->f_mapping);
2283
2284         return ret;
2285 }
2286 #else
2287 #define pagemap_scan_hugetlb_entry NULL
2288 #endif
2289
2290 static int pagemap_scan_pte_hole(unsigned long addr, unsigned long end,
2291                                  int depth, struct mm_walk *walk)
2292 {
2293         struct pagemap_scan_private *p = walk->private;
2294         struct vm_area_struct *vma = walk->vma;
2295         int ret, err;
2296
2297         if (!vma || !pagemap_scan_is_interesting_page(p->cur_vma_category, p))
2298                 return 0;
2299
2300         ret = pagemap_scan_output(p->cur_vma_category, p, addr, &end);
2301         if (addr == end)
2302                 return ret;
2303
2304         if (~p->arg.flags & PM_SCAN_WP_MATCHING)
2305                 return ret;
2306
2307         err = uffd_wp_range(vma, addr, end - addr, true);
2308         if (err < 0)
2309                 ret = err;
2310
2311         return ret;
2312 }
2313
2314 static const struct mm_walk_ops pagemap_scan_ops = {
2315         .test_walk = pagemap_scan_test_walk,
2316         .pmd_entry = pagemap_scan_pmd_entry,
2317         .pte_hole = pagemap_scan_pte_hole,
2318         .hugetlb_entry = pagemap_scan_hugetlb_entry,
2319 };
2320
2321 static int pagemap_scan_get_args(struct pm_scan_arg *arg,
2322                                  unsigned long uarg)
2323 {
2324         if (copy_from_user(arg, (void __user *)uarg, sizeof(*arg)))
2325                 return -EFAULT;
2326
2327         if (arg->size != sizeof(struct pm_scan_arg))
2328                 return -EINVAL;
2329
2330         /* Validate requested features */
2331         if (arg->flags & ~PM_SCAN_FLAGS)
2332                 return -EINVAL;
2333         if ((arg->category_inverted | arg->category_mask |
2334              arg->category_anyof_mask | arg->return_mask) & ~PM_SCAN_CATEGORIES)
2335                 return -EINVAL;
2336
2337         arg->start = untagged_addr((unsigned long)arg->start);
2338         arg->end = untagged_addr((unsigned long)arg->end);
2339         arg->vec = untagged_addr((unsigned long)arg->vec);
2340
2341         /* Validate memory pointers */
2342         if (!IS_ALIGNED(arg->start, PAGE_SIZE))
2343                 return -EINVAL;
2344         if (!access_ok((void __user *)(long)arg->start, arg->end - arg->start))
2345                 return -EFAULT;
2346         if (!arg->vec && arg->vec_len)
2347                 return -EINVAL;
2348         if (arg->vec && !access_ok((void __user *)(long)arg->vec,
2349                               arg->vec_len * sizeof(struct page_region)))
2350                 return -EFAULT;
2351
2352         /* Fixup default values */
2353         arg->end = ALIGN(arg->end, PAGE_SIZE);
2354         arg->walk_end = 0;
2355         if (!arg->max_pages)
2356                 arg->max_pages = ULONG_MAX;
2357
2358         return 0;
2359 }
2360
2361 static int pagemap_scan_writeback_args(struct pm_scan_arg *arg,
2362                                        unsigned long uargl)
2363 {
2364         struct pm_scan_arg __user *uarg = (void __user *)uargl;
2365
2366         if (copy_to_user(&uarg->walk_end, &arg->walk_end, sizeof(arg->walk_end)))
2367                 return -EFAULT;
2368
2369         return 0;
2370 }
2371
2372 static int pagemap_scan_init_bounce_buffer(struct pagemap_scan_private *p)
2373 {
2374         if (!p->arg.vec_len)
2375                 return 0;
2376
2377         p->vec_buf_len = min_t(size_t, PAGEMAP_WALK_SIZE >> PAGE_SHIFT,
2378                                p->arg.vec_len);
2379         p->vec_buf = kmalloc_array(p->vec_buf_len, sizeof(*p->vec_buf),
2380                                    GFP_KERNEL);
2381         if (!p->vec_buf)
2382                 return -ENOMEM;
2383
2384         p->vec_buf->start = p->vec_buf->end = 0;
2385         p->vec_out = (struct page_region __user *)(long)p->arg.vec;
2386
2387         return 0;
2388 }
2389
2390 static long pagemap_scan_flush_buffer(struct pagemap_scan_private *p)
2391 {
2392         const struct page_region *buf = p->vec_buf;
2393         long n = p->vec_buf_index;
2394
2395         if (!p->vec_buf)
2396                 return 0;
2397
2398         if (buf[n].end != buf[n].start)
2399                 n++;
2400
2401         if (!n)
2402                 return 0;
2403
2404         if (copy_to_user(p->vec_out, buf, n * sizeof(*buf)))
2405                 return -EFAULT;
2406
2407         p->arg.vec_len -= n;
2408         p->vec_out += n;
2409
2410         p->vec_buf_index = 0;
2411         p->vec_buf_len = min_t(size_t, p->vec_buf_len, p->arg.vec_len);
2412         p->vec_buf->start = p->vec_buf->end = 0;
2413
2414         return n;
2415 }
2416
2417 static long do_pagemap_scan(struct mm_struct *mm, unsigned long uarg)
2418 {
2419         struct mmu_notifier_range range;
2420         struct pagemap_scan_private p = {0};
2421         unsigned long walk_start;
2422         size_t n_ranges_out = 0;
2423         int ret;
2424
2425         ret = pagemap_scan_get_args(&p.arg, uarg);
2426         if (ret)
2427                 return ret;
2428
2429         p.masks_of_interest = p.arg.category_mask | p.arg.category_anyof_mask |
2430                               p.arg.return_mask;
2431         ret = pagemap_scan_init_bounce_buffer(&p);
2432         if (ret)
2433                 return ret;
2434
2435         /* Protection change for the range is going to happen. */
2436         if (p.arg.flags & PM_SCAN_WP_MATCHING) {
2437                 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA, 0,
2438                                         mm, p.arg.start, p.arg.end);
2439                 mmu_notifier_invalidate_range_start(&range);
2440         }
2441
2442         for (walk_start = p.arg.start; walk_start < p.arg.end;
2443                         walk_start = p.arg.walk_end) {
2444                 long n_out;
2445
2446                 if (fatal_signal_pending(current)) {
2447                         ret = -EINTR;
2448                         break;
2449                 }
2450
2451                 ret = mmap_read_lock_killable(mm);
2452                 if (ret)
2453                         break;
2454                 ret = walk_page_range(mm, walk_start, p.arg.end,
2455                                       &pagemap_scan_ops, &p);
2456                 mmap_read_unlock(mm);
2457
2458                 n_out = pagemap_scan_flush_buffer(&p);
2459                 if (n_out < 0)
2460                         ret = n_out;
2461                 else
2462                         n_ranges_out += n_out;
2463
2464                 if (ret != -ENOSPC)
2465                         break;
2466
2467                 if (p.arg.vec_len == 0 || p.found_pages == p.arg.max_pages)
2468                         break;
2469         }
2470
2471         /* ENOSPC signifies early stop (buffer full) from the walk. */
2472         if (!ret || ret == -ENOSPC)
2473                 ret = n_ranges_out;
2474
2475         /* The walk_end isn't set when ret is zero */
2476         if (!p.arg.walk_end)
2477                 p.arg.walk_end = p.arg.end;
2478         if (pagemap_scan_writeback_args(&p.arg, uarg))
2479                 ret = -EFAULT;
2480
2481         if (p.arg.flags & PM_SCAN_WP_MATCHING)
2482                 mmu_notifier_invalidate_range_end(&range);
2483
2484         kfree(p.vec_buf);
2485         return ret;
2486 }
2487
2488 static long do_pagemap_cmd(struct file *file, unsigned int cmd,
2489                            unsigned long arg)
2490 {
2491         struct mm_struct *mm = file->private_data;
2492
2493         switch (cmd) {
2494         case PAGEMAP_SCAN:
2495                 return do_pagemap_scan(mm, arg);
2496
2497         default:
2498                 return -EINVAL;
2499         }
2500 }
2501
2502 const struct file_operations proc_pagemap_operations = {
2503         .llseek         = mem_lseek, /* borrow this */
2504         .read           = pagemap_read,
2505         .open           = pagemap_open,
2506         .release        = pagemap_release,
2507         .unlocked_ioctl = do_pagemap_cmd,
2508         .compat_ioctl   = do_pagemap_cmd,
2509 };
2510 #endif /* CONFIG_PROC_PAGE_MONITOR */
2511
2512 #ifdef CONFIG_NUMA
2513
2514 struct numa_maps {
2515         unsigned long pages;
2516         unsigned long anon;
2517         unsigned long active;
2518         unsigned long writeback;
2519         unsigned long mapcount_max;
2520         unsigned long dirty;
2521         unsigned long swapcache;
2522         unsigned long node[MAX_NUMNODES];
2523 };
2524
2525 struct numa_maps_private {
2526         struct proc_maps_private proc_maps;
2527         struct numa_maps md;
2528 };
2529
2530 static void gather_stats(struct page *page, struct numa_maps *md, int pte_dirty,
2531                         unsigned long nr_pages)
2532 {
2533         int count = page_mapcount(page);
2534
2535         md->pages += nr_pages;
2536         if (pte_dirty || PageDirty(page))
2537                 md->dirty += nr_pages;
2538
2539         if (PageSwapCache(page))
2540                 md->swapcache += nr_pages;
2541
2542         if (PageActive(page) || PageUnevictable(page))
2543                 md->active += nr_pages;
2544
2545         if (PageWriteback(page))
2546                 md->writeback += nr_pages;
2547
2548         if (PageAnon(page))
2549                 md->anon += nr_pages;
2550
2551         if (count > md->mapcount_max)
2552                 md->mapcount_max = count;
2553
2554         md->node[page_to_nid(page)] += nr_pages;
2555 }
2556
2557 static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
2558                 unsigned long addr)
2559 {
2560         struct page *page;
2561         int nid;
2562
2563         if (!pte_present(pte))
2564                 return NULL;
2565
2566         page = vm_normal_page(vma, addr, pte);
2567         if (!page || is_zone_device_page(page))
2568                 return NULL;
2569
2570         if (PageReserved(page))
2571                 return NULL;
2572
2573         nid = page_to_nid(page);
2574         if (!node_isset(nid, node_states[N_MEMORY]))
2575                 return NULL;
2576
2577         return page;
2578 }
2579
2580 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2581 static struct page *can_gather_numa_stats_pmd(pmd_t pmd,
2582                                               struct vm_area_struct *vma,
2583                                               unsigned long addr)
2584 {
2585         struct page *page;
2586         int nid;
2587
2588         if (!pmd_present(pmd))
2589                 return NULL;
2590
2591         page = vm_normal_page_pmd(vma, addr, pmd);
2592         if (!page)
2593                 return NULL;
2594
2595         if (PageReserved(page))
2596                 return NULL;
2597
2598         nid = page_to_nid(page);
2599         if (!node_isset(nid, node_states[N_MEMORY]))
2600                 return NULL;
2601
2602         return page;
2603 }
2604 #endif
2605
2606 static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
2607                 unsigned long end, struct mm_walk *walk)
2608 {
2609         struct numa_maps *md = walk->private;
2610         struct vm_area_struct *vma = walk->vma;
2611         spinlock_t *ptl;
2612         pte_t *orig_pte;
2613         pte_t *pte;
2614
2615 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2616         ptl = pmd_trans_huge_lock(pmd, vma);
2617         if (ptl) {
2618                 struct page *page;
2619
2620                 page = can_gather_numa_stats_pmd(*pmd, vma, addr);
2621                 if (page)
2622                         gather_stats(page, md, pmd_dirty(*pmd),
2623                                      HPAGE_PMD_SIZE/PAGE_SIZE);
2624                 spin_unlock(ptl);
2625                 return 0;
2626         }
2627 #endif
2628         orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
2629         if (!pte) {
2630                 walk->action = ACTION_AGAIN;
2631                 return 0;
2632         }
2633         do {
2634                 pte_t ptent = ptep_get(pte);
2635                 struct page *page = can_gather_numa_stats(ptent, vma, addr);
2636                 if (!page)
2637                         continue;
2638                 gather_stats(page, md, pte_dirty(ptent), 1);
2639
2640         } while (pte++, addr += PAGE_SIZE, addr != end);
2641         pte_unmap_unlock(orig_pte, ptl);
2642         cond_resched();
2643         return 0;
2644 }
2645 #ifdef CONFIG_HUGETLB_PAGE
2646 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
2647                 unsigned long addr, unsigned long end, struct mm_walk *walk)
2648 {
2649         pte_t huge_pte = huge_ptep_get(pte);
2650         struct numa_maps *md;
2651         struct page *page;
2652
2653         if (!pte_present(huge_pte))
2654                 return 0;
2655
2656         page = pte_page(huge_pte);
2657
2658         md = walk->private;
2659         gather_stats(page, md, pte_dirty(huge_pte), 1);
2660         return 0;
2661 }
2662
2663 #else
2664 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
2665                 unsigned long addr, unsigned long end, struct mm_walk *walk)
2666 {
2667         return 0;
2668 }
2669 #endif
2670
2671 static const struct mm_walk_ops show_numa_ops = {
2672         .hugetlb_entry = gather_hugetlb_stats,
2673         .pmd_entry = gather_pte_stats,
2674         .walk_lock = PGWALK_RDLOCK,
2675 };
2676
2677 /*
2678  * Display pages allocated per node and memory policy via /proc.
2679  */
2680 static int show_numa_map(struct seq_file *m, void *v)
2681 {
2682         struct numa_maps_private *numa_priv = m->private;
2683         struct proc_maps_private *proc_priv = &numa_priv->proc_maps;
2684         struct vm_area_struct *vma = v;
2685         struct numa_maps *md = &numa_priv->md;
2686         struct file *file = vma->vm_file;
2687         struct mm_struct *mm = vma->vm_mm;
2688         char buffer[64];
2689         struct mempolicy *pol;
2690         pgoff_t ilx;
2691         int nid;
2692
2693         if (!mm)
2694                 return 0;
2695
2696         /* Ensure we start with an empty set of numa_maps statistics. */
2697         memset(md, 0, sizeof(*md));
2698
2699         pol = __get_vma_policy(vma, vma->vm_start, &ilx);
2700         if (pol) {
2701                 mpol_to_str(buffer, sizeof(buffer), pol);
2702                 mpol_cond_put(pol);
2703         } else {
2704                 mpol_to_str(buffer, sizeof(buffer), proc_priv->task_mempolicy);
2705         }
2706
2707         seq_printf(m, "%08lx %s", vma->vm_start, buffer);
2708
2709         if (file) {
2710                 seq_puts(m, " file=");
2711                 seq_path(m, file_user_path(file), "\n\t= ");
2712         } else if (vma_is_initial_heap(vma)) {
2713                 seq_puts(m, " heap");
2714         } else if (vma_is_initial_stack(vma)) {
2715                 seq_puts(m, " stack");
2716         }
2717
2718         if (is_vm_hugetlb_page(vma))
2719                 seq_puts(m, " huge");
2720
2721         /* mmap_lock is held by m_start */
2722         walk_page_vma(vma, &show_numa_ops, md);
2723
2724         if (!md->pages)
2725                 goto out;
2726
2727         if (md->anon)
2728                 seq_printf(m, " anon=%lu", md->anon);
2729
2730         if (md->dirty)
2731                 seq_printf(m, " dirty=%lu", md->dirty);
2732
2733         if (md->pages != md->anon && md->pages != md->dirty)
2734                 seq_printf(m, " mapped=%lu", md->pages);
2735
2736         if (md->mapcount_max > 1)
2737                 seq_printf(m, " mapmax=%lu", md->mapcount_max);
2738
2739         if (md->swapcache)
2740                 seq_printf(m, " swapcache=%lu", md->swapcache);
2741
2742         if (md->active < md->pages && !is_vm_hugetlb_page(vma))
2743                 seq_printf(m, " active=%lu", md->active);
2744
2745         if (md->writeback)
2746                 seq_printf(m, " writeback=%lu", md->writeback);
2747
2748         for_each_node_state(nid, N_MEMORY)
2749                 if (md->node[nid])
2750                         seq_printf(m, " N%d=%lu", nid, md->node[nid]);
2751
2752         seq_printf(m, " kernelpagesize_kB=%lu", vma_kernel_pagesize(vma) >> 10);
2753 out:
2754         seq_putc(m, '\n');
2755         return 0;
2756 }
2757
2758 static const struct seq_operations proc_pid_numa_maps_op = {
2759         .start  = m_start,
2760         .next   = m_next,
2761         .stop   = m_stop,
2762         .show   = show_numa_map,
2763 };
2764
2765 static int pid_numa_maps_open(struct inode *inode, struct file *file)
2766 {
2767         return proc_maps_open(inode, file, &proc_pid_numa_maps_op,
2768                                 sizeof(struct numa_maps_private));
2769 }
2770
2771 const struct file_operations proc_pid_numa_maps_operations = {
2772         .open           = pid_numa_maps_open,
2773         .read           = seq_read,
2774         .llseek         = seq_lseek,
2775         .release        = proc_map_release,
2776 };
2777
2778 #endif /* CONFIG_NUMA */