fs/proc/task_mmu.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/mm.h>
   3 #include <linux/vmacache.h>
   4 #include <linux/hugetlb.h>
   5 #include <linux/huge_mm.h>
   6 #include <linux/mount.h>
   7 #include <linux/seq_file.h>
   8 #include <linux/highmem.h>
   9 #include <linux/ptrace.h>
  10 #include <linux/slab.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/mempolicy.h>
  13 #include <linux/rmap.h>
  14 #include <linux/swap.h>
  15 #include <linux/sched/mm.h>
  16 #include <linux/swapops.h>
  17 #include <linux/mmu_notifier.h>
  18 #include <linux/page_idle.h>
  19 #include <linux/shmem_fs.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/pkeys.h>
  22
  23 #include <asm/elf.h>
  24 #include <asm/tlb.h>
  25 #include <asm/tlbflush.h>
  26 #include "internal.h"
  27
  28 #define SEQ_PUT_DEC(str, val) \
  29                 seq_put_decimal_ull_width(m, str, (val) << (PAGE_SHIFT-10), 8)
  30 void task_mem(struct seq_file *m, struct mm_struct *mm)
  31 {
  32         unsigned long text, lib, swap, anon, file, shmem;
  33         unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
  34
  35         anon = get_mm_counter(mm, MM_ANONPAGES);
  36         file = get_mm_counter(mm, MM_FILEPAGES);
  37         shmem = get_mm_counter(mm, MM_SHMEMPAGES);
  38
  39         /*
  40          * Note: to minimize their overhead, mm maintains hiwater_vm and
  41          * hiwater_rss only when about to *lower* total_vm or rss.  Any
  42          * collector of these hiwater stats must therefore get total_vm
  43          * and rss too, which will usually be the higher.  Barriers? not
  44          * worth the effort, such snapshots can always be inconsistent.
  45          */
  46         hiwater_vm = total_vm = mm->total_vm;
  47         if (hiwater_vm < mm->hiwater_vm)
  48                 hiwater_vm = mm->hiwater_vm;
  49         hiwater_rss = total_rss = anon + file + shmem;
  50         if (hiwater_rss < mm->hiwater_rss)
  51                 hiwater_rss = mm->hiwater_rss;
  52
  53         /* split executable areas between text and lib */
  54         text = PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK);
  55         text = min(text, mm->exec_vm << PAGE_SHIFT);
  56         lib = (mm->exec_vm << PAGE_SHIFT) - text;
  57
  58         swap = get_mm_counter(mm, MM_SWAPENTS);
  59         SEQ_PUT_DEC("VmPeak:\t", hiwater_vm);
  60         SEQ_PUT_DEC(" kB\nVmSize:\t", total_vm);
  61         SEQ_PUT_DEC(" kB\nVmLck:\t", mm->locked_vm);
  62         SEQ_PUT_DEC(" kB\nVmPin:\t", mm->pinned_vm);
  63         SEQ_PUT_DEC(" kB\nVmHWM:\t", hiwater_rss);
  64         SEQ_PUT_DEC(" kB\nVmRSS:\t", total_rss);
  65         SEQ_PUT_DEC(" kB\nRssAnon:\t", anon);
  66         SEQ_PUT_DEC(" kB\nRssFile:\t", file);
  67         SEQ_PUT_DEC(" kB\nRssShmem:\t", shmem);
  68         SEQ_PUT_DEC(" kB\nVmData:\t", mm->data_vm);
  69         SEQ_PUT_DEC(" kB\nVmStk:\t", mm->stack_vm);
  70         seq_put_decimal_ull_width(m,
  71                     " kB\nVmExe:\t", text >> 10, 8);
  72         seq_put_decimal_ull_width(m,
  73                     " kB\nVmLib:\t", lib >> 10, 8);
  74         seq_put_decimal_ull_width(m,
  75                     " kB\nVmPTE:\t", mm_pgtables_bytes(mm) >> 10, 8);
  76         SEQ_PUT_DEC(" kB\nVmSwap:\t", swap);
  77         seq_puts(m, " kB\n");
  78         hugetlb_report_usage(m, mm);
  79 }
  80 #undef SEQ_PUT_DEC
  81
  82 unsigned long task_vsize(struct mm_struct *mm)
  83 {
  84         return PAGE_SIZE * mm->total_vm;
  85 }
  86
  87 unsigned long task_statm(struct mm_struct *mm,
  88                          unsigned long *shared, unsigned long *text,
  89                          unsigned long *data, unsigned long *resident)
  90 {
  91         *shared = get_mm_counter(mm, MM_FILEPAGES) +
  92                         get_mm_counter(mm, MM_SHMEMPAGES);
  93         *text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
  94                                                                 >> PAGE_SHIFT;
  95         *data = mm->data_vm + mm->stack_vm;
  96         *resident = *shared + get_mm_counter(mm, MM_ANONPAGES);
  97         return mm->total_vm;
  98 }
  99
 100 #ifdef CONFIG_NUMA
 101 /*
 102  * Save get_task_policy() for show_numa_map().
 103  */
 104 static void hold_task_mempolicy(struct proc_maps_private *priv)
 105 {
 106         struct task_struct *task = priv->task;
 107
 108         task_lock(task);
 109         priv->task_mempolicy = get_task_policy(task);
 110         mpol_get(priv->task_mempolicy);
 111         task_unlock(task);
 112 }
 113 static void release_task_mempolicy(struct proc_maps_private *priv)
 114 {
 115         mpol_put(priv->task_mempolicy);
 116 }
 117 #else
 118 static void hold_task_mempolicy(struct proc_maps_private *priv)
 119 {
 120 }
 121 static void release_task_mempolicy(struct proc_maps_private *priv)
 122 {
 123 }
 124 #endif
 125
 126 static void vma_stop(struct proc_maps_private *priv)
 127 {
 128         struct mm_struct *mm = priv->mm;
 129
 130         release_task_mempolicy(priv);
 131         up_read(&mm->mmap_sem);
 132         mmput(mm);
 133 }
 134
 135 static struct vm_area_struct *
 136 m_next_vma(struct proc_maps_private *priv, struct vm_area_struct *vma)
 137 {
 138         if (vma == priv->tail_vma)
 139                 return NULL;
 140         return vma->vm_next ?: priv->tail_vma;
 141 }
 142
 143 static void m_cache_vma(struct seq_file *m, struct vm_area_struct *vma)
 144 {
 145         if (m->count < m->size) /* vma is copied successfully */
 146                 m->version = m_next_vma(m->private, vma) ? vma->vm_end : -1UL;
 147 }
 148
 149 static void *m_start(struct seq_file *m, loff_t *ppos)
 150 {
 151         struct proc_maps_private *priv = m->private;
 152         unsigned long last_addr = m->version;
 153         struct mm_struct *mm;
 154         struct vm_area_struct *vma;
 155         unsigned int pos = *ppos;
 156
 157         /* See m_cache_vma(). Zero at the start or after lseek. */
 158         if (last_addr == -1UL)
 159                 return NULL;
 160
 161         priv->task = get_proc_task(priv->inode);
 162         if (!priv->task)
 163                 return ERR_PTR(-ESRCH);
 164
 165         mm = priv->mm;
 166         if (!mm || !mmget_not_zero(mm))
 167                 return NULL;
 168
 169         if (down_read_killable(&mm->mmap_sem)) {
 170                 mmput(mm);
 171                 return ERR_PTR(-EINTR);
 172         }
 173
 174         hold_task_mempolicy(priv);
 175         priv->tail_vma = get_gate_vma(mm);
 176
 177         if (last_addr) {
 178                 vma = find_vma(mm, last_addr - 1);
 179                 if (vma && vma->vm_start <= last_addr)
 180                         vma = m_next_vma(priv, vma);
 181                 if (vma)
 182                         return vma;
 183         }
 184
 185         m->version = 0;
 186         if (pos < mm->map_count) {
 187                 for (vma = mm->mmap; pos; pos--) {
 188                         m->version = vma->vm_start;
 189                         vma = vma->vm_next;
 190                 }
 191                 return vma;
 192         }
 193
 194         /* we do not bother to update m->version in this case */
 195         if (pos == mm->map_count && priv->tail_vma)
 196                 return priv->tail_vma;
 197
 198         vma_stop(priv);
 199         return NULL;
 200 }
 201
 202 static void *m_next(struct seq_file *m, void *v, loff_t *pos)
 203 {
 204         struct proc_maps_private *priv = m->private;
 205         struct vm_area_struct *next;
 206
 207         (*pos)++;
 208         next = m_next_vma(priv, v);
 209         if (!next)
 210                 vma_stop(priv);
 211         return next;
 212 }
 213
 214 static void m_stop(struct seq_file *m, void *v)
 215 {
 216         struct proc_maps_private *priv = m->private;
 217
 218         if (!IS_ERR_OR_NULL(v))
 219                 vma_stop(priv);
 220         if (priv->task) {
 221                 put_task_struct(priv->task);
 222                 priv->task = NULL;
 223         }
 224 }
 225
 226 static int proc_maps_open(struct inode *inode, struct file *file,
 227                         const struct seq_operations *ops, int psize)
 228 {
 229         struct proc_maps_private *priv = __seq_open_private(file, ops, psize);
 230
 231         if (!priv)
 232                 return -ENOMEM;
 233
 234         priv->inode = inode;
 235         priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
 236         if (IS_ERR(priv->mm)) {
 237                 int err = PTR_ERR(priv->mm);
 238
 239                 seq_release_private(inode, file);
 240                 return err;
 241         }
 242
 243         return 0;
 244 }
 245
 246 static int proc_map_release(struct inode *inode, struct file *file)
 247 {
 248         struct seq_file *seq = file->private_data;
 249         struct proc_maps_private *priv = seq->private;
 250
 251         if (priv->mm)
 252                 mmdrop(priv->mm);
 253
 254         return seq_release_private(inode, file);
 255 }
 256
 257 static int do_maps_open(struct inode *inode, struct file *file,
 258                         const struct seq_operations *ops)
 259 {
 260         return proc_maps_open(inode, file, ops,
 261                                 sizeof(struct proc_maps_private));
 262 }
 263
 264 /*
 265  * Indicate if the VMA is a stack for the given task; for
 266  * /proc/PID/maps that is the stack of the main task.
 267  */
 268 static int is_stack(struct vm_area_struct *vma)
 269 {
 270         /*
 271          * We make no effort to guess what a given thread considers to be
 272          * its "stack".  It's not even well-defined for programs written
 273          * languages like Go.
 274          */
 275         return vma->vm_start <= vma->vm_mm->start_stack &&
 276                 vma->vm_end >= vma->vm_mm->start_stack;
 277 }
 278
 279 static void show_vma_header_prefix(struct seq_file *m,
 280                                    unsigned long start, unsigned long end,
 281                                    vm_flags_t flags, unsigned long long pgoff,
 282                                    dev_t dev, unsigned long ino)
 283 {
 284         seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
 285         seq_put_hex_ll(m, NULL, start, 8);
 286         seq_put_hex_ll(m, "-", end, 8);
 287         seq_putc(m, ' ');
 288         seq_putc(m, flags & VM_READ ? 'r' : '-');
 289         seq_putc(m, flags & VM_WRITE ? 'w' : '-');
 290         seq_putc(m, flags & VM_EXEC ? 'x' : '-');
 291         seq_putc(m, flags & VM_MAYSHARE ? 's' : 'p');
 292         seq_put_hex_ll(m, " ", pgoff, 8);
 293         seq_put_hex_ll(m, " ", MAJOR(dev), 2);
 294         seq_put_hex_ll(m, ":", MINOR(dev), 2);
 295         seq_put_decimal_ull(m, " ", ino);
 296         seq_putc(m, ' ');
 297 }
 298
 299 static void
 300 show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
 301 {
 302         struct mm_struct *mm = vma->vm_mm;
 303         struct file *file = vma->vm_file;
 304         vm_flags_t flags = vma->vm_flags;
 305         unsigned long ino = 0;
 306         unsigned long long pgoff = 0;
 307         unsigned long start, end;
 308         dev_t dev = 0;
 309         const char *name = NULL;
 310
 311         if (file) {
 312                 struct inode *inode = file_inode(vma->vm_file);
 313                 dev = inode->i_sb->s_dev;
 314                 ino = inode->i_ino;
 315                 pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
 316         }
 317
 318         start = vma->vm_start;
 319         end = vma->vm_end;
 320         show_vma_header_prefix(m, start, end, flags, pgoff, dev, ino);
 321
 322         /*
 323          * Print the dentry name for named mappings, and a
 324          * special [heap] marker for the heap:
 325          */
 326         if (file) {
 327                 seq_pad(m, ' ');
 328                 seq_file_path(m, file, "\n");
 329                 goto done;
 330         }
 331
 332         if (vma->vm_ops && vma->vm_ops->name) {
 333                 name = vma->vm_ops->name(vma);
 334                 if (name)
 335                         goto done;
 336         }
 337
 338         name = arch_vma_name(vma);
 339         if (!name) {
 340                 if (!mm) {
 341                         name = "[vdso]";
 342                         goto done;
 343                 }
 344
 345                 if (vma->vm_start <= mm->brk &&
 346                     vma->vm_end >= mm->start_brk) {
 347                         name = "[heap]";
 348                         goto done;
 349                 }
 350
 351                 if (is_stack(vma))
 352                         name = "[stack]";
 353         }
 354
 355 done:
 356         if (name) {
 357                 seq_pad(m, ' ');
 358                 seq_puts(m, name);
 359         }
 360         seq_putc(m, '\n');
 361 }
 362
 363 static int show_map(struct seq_file *m, void *v)
 364 {
 365         show_map_vma(m, v);
 366         m_cache_vma(m, v);
 367         return 0;
 368 }
 369
 370 static const struct seq_operations proc_pid_maps_op = {
 371         .start  = m_start,
 372         .next   = m_next,
 373         .stop   = m_stop,
 374         .show   = show_map
 375 };
 376
 377 static int pid_maps_open(struct inode *inode, struct file *file)
 378 {
 379         return do_maps_open(inode, file, &proc_pid_maps_op);
 380 }
 381
 382 const struct file_operations proc_pid_maps_operations = {
 383         .open           = pid_maps_open,
 384         .read           = seq_read,
 385         .llseek         = seq_lseek,
 386         .release        = proc_map_release,
 387 };
 388
 389 /*
 390  * Proportional Set Size(PSS): my share of RSS.
 391  *
 392  * PSS of a process is the count of pages it has in memory, where each
 393  * page is divided by the number of processes sharing it.  So if a
 394  * process has 1000 pages all to itself, and 1000 shared with one other
 395  * process, its PSS will be 1500.
 396  *
 397  * To keep (accumulated) division errors low, we adopt a 64bit
 398  * fixed-point pss counter to minimize division errors. So (pss >>
 399  * PSS_SHIFT) would be the real byte count.
 400  *
 401  * A shift of 12 before division means (assuming 4K page size):
 402  *      - 1M 3-user-pages add up to 8KB errors;
 403  *      - supports mapcount up to 2^24, or 16M;
 404  *      - supports PSS up to 2^52 bytes, or 4PB.
 405  */
 406 #define PSS_SHIFT 12
 407
 408 #ifdef CONFIG_PROC_PAGE_MONITOR
 409 struct mem_size_stats {
 410         unsigned long resident;
 411         unsigned long shared_clean;
 412         unsigned long shared_dirty;
 413         unsigned long private_clean;
 414         unsigned long private_dirty;
 415         unsigned long referenced;
 416         unsigned long anonymous;
 417         unsigned long lazyfree;
 418         unsigned long anonymous_thp;
 419         unsigned long shmem_thp;
 420         unsigned long swap;
 421         unsigned long shared_hugetlb;
 422         unsigned long private_hugetlb;
 423         u64 pss;
 424         u64 pss_locked;
 425         u64 swap_pss;
 426         bool check_shmem_swap;
 427 };
 428
 429 static void smaps_account(struct mem_size_stats *mss, struct page *page,
 430                 bool compound, bool young, bool dirty, bool locked)
 431 {
 432         int i, nr = compound ? 1 << compound_order(page) : 1;
 433         unsigned long size = nr * PAGE_SIZE;
 434
 435         if (PageAnon(page)) {
 436                 mss->anonymous += size;
 437                 if (!PageSwapBacked(page) && !dirty && !PageDirty(page))
 438                         mss->lazyfree += size;
 439         }
 440
 441         mss->resident += size;
 442         /* Accumulate the size in pages that have been accessed. */
 443         if (young || page_is_young(page) || PageReferenced(page))
 444                 mss->referenced += size;
 445
 446         /*
 447          * page_count(page) == 1 guarantees the page is mapped exactly once.
 448          * If any subpage of the compound page mapped with PTE it would elevate
 449          * page_count().
 450          */
 451         if (page_count(page) == 1) {
 452                 if (dirty || PageDirty(page))
 453                         mss->private_dirty += size;
 454                 else
 455                         mss->private_clean += size;
 456                 mss->pss += (u64)size << PSS_SHIFT;
 457                 if (locked)
 458                         mss->pss_locked += (u64)size << PSS_SHIFT;
 459                 return;
 460         }
 461
 462         for (i = 0; i < nr; i++, page++) {
 463                 int mapcount = page_mapcount(page);
 464                 unsigned long pss = (PAGE_SIZE << PSS_SHIFT);
 465
 466                 if (mapcount >= 2) {
 467                         if (dirty || PageDirty(page))
 468                                 mss->shared_dirty += PAGE_SIZE;
 469                         else
 470                                 mss->shared_clean += PAGE_SIZE;
 471                         mss->pss += pss / mapcount;
 472                         if (locked)
 473                                 mss->pss_locked += pss / mapcount;
 474                 } else {
 475                         if (dirty || PageDirty(page))
 476                                 mss->private_dirty += PAGE_SIZE;
 477                         else
 478                                 mss->private_clean += PAGE_SIZE;
 479                         mss->pss += pss;
 480                         if (locked)
 481                                 mss->pss_locked += pss;
 482                 }
 483         }
 484 }
 485
 486 #ifdef CONFIG_SHMEM
 487 static int smaps_pte_hole(unsigned long addr, unsigned long end,
 488                 struct mm_walk *walk)
 489 {
 490         struct mem_size_stats *mss = walk->private;
 491
 492         mss->swap += shmem_partial_swap_usage(
 493                         walk->vma->vm_file->f_mapping, addr, end);
 494
 495         return 0;
 496 }
 497 #endif
 498
 499 static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 500                 struct mm_walk *walk)
 501 {
 502         struct mem_size_stats *mss = walk->private;
 503         struct vm_area_struct *vma = walk->vma;
 504         bool locked = !!(vma->vm_flags & VM_LOCKED);
 505         struct page *page = NULL;
 506
 507         if (pte_present(*pte)) {
 508                 page = vm_normal_page(vma, addr, *pte);
 509         } else if (is_swap_pte(*pte)) {
 510                 swp_entry_t swpent = pte_to_swp_entry(*pte);
 511
 512                 if (!non_swap_entry(swpent)) {
 513                         int mapcount;
 514
 515                         mss->swap += PAGE_SIZE;
 516                         mapcount = swp_swapcount(swpent);
 517                         if (mapcount >= 2) {
 518                                 u64 pss_delta = (u64)PAGE_SIZE << PSS_SHIFT;
 519
 520                                 do_div(pss_delta, mapcount);
 521                                 mss->swap_pss += pss_delta;
 522                         } else {
 523                                 mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT;
 524                         }
 525                 } else if (is_migration_entry(swpent))
 526                         page = migration_entry_to_page(swpent);
 527                 else if (is_device_private_entry(swpent))
 528                         page = device_private_entry_to_page(swpent);
 529         } else if (unlikely(IS_ENABLED(CONFIG_SHMEM) && mss->check_shmem_swap
 530                                                         && pte_none(*pte))) {
 531                 page = find_get_entry(vma->vm_file->f_mapping,
 532                                                 linear_page_index(vma, addr));
 533                 if (!page)
 534                         return;
 535
 536                 if (radix_tree_exceptional_entry(page))
 537                         mss->swap += PAGE_SIZE;
 538                 else
 539                         put_page(page);
 540
 541                 return;
 542         }
 543
 544         if (!page)
 545                 return;
 546
 547         smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte), locked);
 548 }
 549
 550 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 551 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 552                 struct mm_walk *walk)
 553 {
 554         struct mem_size_stats *mss = walk->private;
 555         struct vm_area_struct *vma = walk->vma;
 556         bool locked = !!(vma->vm_flags & VM_LOCKED);
 557         struct page *page;
 558
 559         /* FOLL_DUMP will return -EFAULT on huge zero page */
 560         page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP);
 561         if (IS_ERR_OR_NULL(page))
 562                 return;
 563         if (PageAnon(page))
 564                 mss->anonymous_thp += HPAGE_PMD_SIZE;
 565         else if (PageSwapBacked(page))
 566                 mss->shmem_thp += HPAGE_PMD_SIZE;
 567         else if (is_zone_device_page(page))
 568                 /* pass */;
 569         else
 570                 VM_BUG_ON_PAGE(1, page);
 571         smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd), locked);
 572 }
 573 #else
 574 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 575                 struct mm_walk *walk)
 576 {
 577 }
 578 #endif
 579
 580 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 581                            struct mm_walk *walk)
 582 {
 583         struct vm_area_struct *vma = walk->vma;
 584         pte_t *pte;
 585         spinlock_t *ptl;
 586
 587         ptl = pmd_trans_huge_lock(pmd, vma);
 588         if (ptl) {
 589                 if (pmd_present(*pmd))
 590                         smaps_pmd_entry(pmd, addr, walk);
 591                 spin_unlock(ptl);
 592                 goto out;
 593         }
 594
 595         if (pmd_trans_unstable(pmd))
 596                 goto out;
 597         /*
 598          * The mmap_sem held all the way back in m_start() is what
 599          * keeps khugepaged out of here and from collapsing things
 600          * in here.
 601          */
 602         pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
 603         for (; addr != end; pte++, addr += PAGE_SIZE)
 604                 smaps_pte_entry(pte, addr, walk);
 605         pte_unmap_unlock(pte - 1, ptl);
 606 out:
 607         cond_resched();
 608         return 0;
 609 }
 610
 611 static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
 612 {
 613         /*
 614          * Don't forget to update Documentation/ on changes.
 615          */
 616         static const char mnemonics[BITS_PER_LONG][2] = {
 617                 /*
 618                  * In case if we meet a flag we don't know about.
 619                  */
 620                 [0 ... (BITS_PER_LONG-1)] = "??",
 621
 622                 [ilog2(VM_READ)]        = "rd",
 623                 [ilog2(VM_WRITE)]       = "wr",
 624                 [ilog2(VM_EXEC)]        = "ex",
 625                 [ilog2(VM_SHARED)]      = "sh",
 626                 [ilog2(VM_MAYREAD)]     = "mr",
 627                 [ilog2(VM_MAYWRITE)]    = "mw",
 628                 [ilog2(VM_MAYEXEC)]     = "me",
 629                 [ilog2(VM_MAYSHARE)]    = "ms",
 630                 [ilog2(VM_GROWSDOWN)]   = "gd",
 631                 [ilog2(VM_PFNMAP)]      = "pf",
 632                 [ilog2(VM_DENYWRITE)]   = "dw",
 633 #ifdef CONFIG_X86_INTEL_MPX
 634                 [ilog2(VM_MPX)]         = "mp",
 635 #endif
 636                 [ilog2(VM_LOCKED)]      = "lo",
 637                 [ilog2(VM_IO)]          = "io",
 638                 [ilog2(VM_SEQ_READ)]    = "sr",
 639                 [ilog2(VM_RAND_READ)]   = "rr",
 640                 [ilog2(VM_DONTCOPY)]    = "dc",
 641                 [ilog2(VM_DONTEXPAND)]  = "de",
 642                 [ilog2(VM_ACCOUNT)]     = "ac",
 643                 [ilog2(VM_NORESERVE)]   = "nr",
 644                 [ilog2(VM_HUGETLB)]     = "ht",
 645                 [ilog2(VM_SYNC)]        = "sf",
 646                 [ilog2(VM_ARCH_1)]      = "ar",
 647                 [ilog2(VM_WIPEONFORK)]  = "wf",
 648                 [ilog2(VM_DONTDUMP)]    = "dd",
 649 #ifdef CONFIG_MEM_SOFT_DIRTY
 650                 [ilog2(VM_SOFTDIRTY)]   = "sd",
 651 #endif
 652                 [ilog2(VM_MIXEDMAP)]    = "mm",
 653                 [ilog2(VM_HUGEPAGE)]    = "hg",
 654                 [ilog2(VM_NOHUGEPAGE)]  = "nh",
 655                 [ilog2(VM_MERGEABLE)]   = "mg",
 656                 [ilog2(VM_UFFD_MISSING)]= "um",
 657                 [ilog2(VM_UFFD_WP)]     = "uw",
 658 #ifdef CONFIG_ARCH_HAS_PKEYS
 659                 /* These come out via ProtectionKey: */
 660                 [ilog2(VM_PKEY_BIT0)]   = "",
 661                 [ilog2(VM_PKEY_BIT1)]   = "",
 662                 [ilog2(VM_PKEY_BIT2)]   = "",
 663                 [ilog2(VM_PKEY_BIT3)]   = "",
 664 #if VM_PKEY_BIT4
 665                 [ilog2(VM_PKEY_BIT4)]   = "",
 666 #endif
 667 #endif /* CONFIG_ARCH_HAS_PKEYS */
 668         };
 669         size_t i;
 670
 671         seq_puts(m, "VmFlags: ");
 672         for (i = 0; i < BITS_PER_LONG; i++) {
 673                 if (!mnemonics[i][0])
 674                         continue;
 675                 if (vma->vm_flags & (1UL << i)) {
 676                         seq_putc(m, mnemonics[i][0]);
 677                         seq_putc(m, mnemonics[i][1]);
 678                         seq_putc(m, ' ');
 679                 }
 680         }
 681         seq_putc(m, '\n');
 682 }
 683
 684 #ifdef CONFIG_HUGETLB_PAGE
 685 static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
 686                                  unsigned long addr, unsigned long end,
 687                                  struct mm_walk *walk)
 688 {
 689         struct mem_size_stats *mss = walk->private;
 690         struct vm_area_struct *vma = walk->vma;
 691         struct page *page = NULL;
 692
 693         if (pte_present(*pte)) {
 694                 page = vm_normal_page(vma, addr, *pte);
 695         } else if (is_swap_pte(*pte)) {
 696                 swp_entry_t swpent = pte_to_swp_entry(*pte);
 697
 698                 if (is_migration_entry(swpent))
 699                         page = migration_entry_to_page(swpent);
 700                 else if (is_device_private_entry(swpent))
 701                         page = device_private_entry_to_page(swpent);
 702         }
 703         if (page) {
 704                 int mapcount = page_mapcount(page);
 705
 706                 if (mapcount >= 2)
 707                         mss->shared_hugetlb += huge_page_size(hstate_vma(vma));
 708                 else
 709                         mss->private_hugetlb += huge_page_size(hstate_vma(vma));
 710         }
 711         return 0;
 712 }
 713 #endif /* HUGETLB_PAGE */
 714
 715 static void smap_gather_stats(struct vm_area_struct *vma,
 716                              struct mem_size_stats *mss)
 717 {
 718         struct mm_walk smaps_walk = {
 719                 .pmd_entry = smaps_pte_range,
 720 #ifdef CONFIG_HUGETLB_PAGE
 721                 .hugetlb_entry = smaps_hugetlb_range,
 722 #endif
 723                 .mm = vma->vm_mm,
 724         };
 725
 726         smaps_walk.private = mss;
 727
 728 #ifdef CONFIG_SHMEM
 729         /* In case of smaps_rollup, reset the value from previous vma */
 730         mss->check_shmem_swap = false;
 731         if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) {
 732                 /*
 733                  * For shared or readonly shmem mappings we know that all
 734                  * swapped out pages belong to the shmem object, and we can
 735                  * obtain the swap value much more efficiently. For private
 736                  * writable mappings, we might have COW pages that are
 737                  * not affected by the parent swapped out pages of the shmem
 738                  * object, so we have to distinguish them during the page walk.
 739                  * Unless we know that the shmem object (or the part mapped by
 740                  * our VMA) has no swapped out pages at all.
 741                  */
 742                 unsigned long shmem_swapped = shmem_swap_usage(vma);
 743
 744                 if (!shmem_swapped || (vma->vm_flags & VM_SHARED) ||
 745                                         !(vma->vm_flags & VM_WRITE)) {
 746                         mss->swap += shmem_swapped;
 747                 } else {
 748                         mss->check_shmem_swap = true;
 749                         smaps_walk.pte_hole = smaps_pte_hole;
 750                 }
 751         }
 752 #endif
 753         /* mmap_sem is held in m_start */
 754         walk_page_vma(vma, &smaps_walk);
 755 }
 756
 757 #define SEQ_PUT_DEC(str, val) \
 758                 seq_put_decimal_ull_width(m, str, (val) >> 10, 8)
 759
 760 /* Show the contents common for smaps and smaps_rollup */
 761 static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss)
 762 {
 763         SEQ_PUT_DEC("Rss:            ", mss->resident);
 764         SEQ_PUT_DEC(" kB\nPss:            ", mss->pss >> PSS_SHIFT);
 765         SEQ_PUT_DEC(" kB\nShared_Clean:   ", mss->shared_clean);
 766         SEQ_PUT_DEC(" kB\nShared_Dirty:   ", mss->shared_dirty);
 767         SEQ_PUT_DEC(" kB\nPrivate_Clean:  ", mss->private_clean);
 768         SEQ_PUT_DEC(" kB\nPrivate_Dirty:  ", mss->private_dirty);
 769         SEQ_PUT_DEC(" kB\nReferenced:     ", mss->referenced);
 770         SEQ_PUT_DEC(" kB\nAnonymous:      ", mss->anonymous);
 771         SEQ_PUT_DEC(" kB\nLazyFree:       ", mss->lazyfree);
 772         SEQ_PUT_DEC(" kB\nAnonHugePages:  ", mss->anonymous_thp);
 773         SEQ_PUT_DEC(" kB\nShmemPmdMapped: ", mss->shmem_thp);
 774         SEQ_PUT_DEC(" kB\nShared_Hugetlb: ", mss->shared_hugetlb);
 775         seq_put_decimal_ull_width(m, " kB\nPrivate_Hugetlb: ",
 776                                   mss->private_hugetlb >> 10, 7);
 777         SEQ_PUT_DEC(" kB\nSwap:           ", mss->swap);
 778         SEQ_PUT_DEC(" kB\nSwapPss:        ",
 779                                         mss->swap_pss >> PSS_SHIFT);
 780         SEQ_PUT_DEC(" kB\nLocked:         ",
 781                                         mss->pss_locked >> PSS_SHIFT);
 782         seq_puts(m, " kB\n");
 783 }
 784
 785 static int show_smap(struct seq_file *m, void *v)
 786 {
 787         struct vm_area_struct *vma = v;
 788         struct mem_size_stats mss;
 789
 790         memset(&mss, 0, sizeof(mss));
 791
 792         smap_gather_stats(vma, &mss);
 793
 794         show_map_vma(m, vma);
 795
 796         SEQ_PUT_DEC("Size:           ", vma->vm_end - vma->vm_start);
 797         SEQ_PUT_DEC(" kB\nKernelPageSize: ", vma_kernel_pagesize(vma));
 798         SEQ_PUT_DEC(" kB\nMMUPageSize:    ", vma_mmu_pagesize(vma));
 799         seq_puts(m, " kB\n");
 800
 801         __show_smap(m, &mss);
 802
 803         seq_printf(m, "THPeligible:    %d\n", transparent_hugepage_enabled(vma));
 804
 805         if (arch_pkeys_enabled())
 806                 seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));
 807         show_smap_vma_flags(m, vma);
 808
 809         m_cache_vma(m, vma);
 810
 811         return 0;
 812 }
 813
 814 static int show_smaps_rollup(struct seq_file *m, void *v)
 815 {
 816         struct proc_maps_private *priv = m->private;
 817         struct mem_size_stats mss;
 818         struct mm_struct *mm;
 819         struct vm_area_struct *vma;
 820         unsigned long last_vma_end = 0;
 821         int ret = 0;
 822
 823         priv->task = get_proc_task(priv->inode);
 824         if (!priv->task)
 825                 return -ESRCH;
 826
 827         mm = priv->mm;
 828         if (!mm || !mmget_not_zero(mm)) {
 829                 ret = -ESRCH;
 830                 goto out_put_task;
 831         }
 832
 833         memset(&mss, 0, sizeof(mss));
 834
 835         ret = down_read_killable(&mm->mmap_sem);
 836         if (ret)
 837                 goto out_put_mm;
 838
 839         hold_task_mempolicy(priv);
 840
 841         for (vma = priv->mm->mmap; vma; vma = vma->vm_next) {
 842                 smap_gather_stats(vma, &mss);
 843                 last_vma_end = vma->vm_end;
 844         }
 845
 846         show_vma_header_prefix(m, priv->mm->mmap->vm_start,
 847                                last_vma_end, 0, 0, 0, 0);
 848         seq_pad(m, ' ');
 849         seq_puts(m, "[rollup]\n");
 850
 851         __show_smap(m, &mss);
 852
 853         release_task_mempolicy(priv);
 854         up_read(&mm->mmap_sem);
 855
 856 out_put_mm:
 857         mmput(mm);
 858 out_put_task:
 859         put_task_struct(priv->task);
 860         priv->task = NULL;
 861
 862         return ret;
 863 }
 864 #undef SEQ_PUT_DEC
 865
 866 static const struct seq_operations proc_pid_smaps_op = {
 867         .start  = m_start,
 868         .next   = m_next,
 869         .stop   = m_stop,
 870         .show   = show_smap
 871 };
 872
 873 static int pid_smaps_open(struct inode *inode, struct file *file)
 874 {
 875         return do_maps_open(inode, file, &proc_pid_smaps_op);
 876 }
 877
 878 static int smaps_rollup_open(struct inode *inode, struct file *file)
 879 {
 880         int ret;
 881         struct proc_maps_private *priv;
 882
 883         priv = kzalloc(sizeof(*priv), GFP_KERNEL_ACCOUNT);
 884         if (!priv)
 885                 return -ENOMEM;
 886
 887         ret = single_open(file, show_smaps_rollup, priv);
 888         if (ret)
 889                 goto out_free;
 890
 891         priv->inode = inode;
 892         priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
 893         if (IS_ERR(priv->mm)) {
 894                 ret = PTR_ERR(priv->mm);
 895
 896                 single_release(inode, file);
 897                 goto out_free;
 898         }
 899
 900         return 0;
 901
 902 out_free:
 903         kfree(priv);
 904         return ret;
 905 }
 906
 907 static int smaps_rollup_release(struct inode *inode, struct file *file)
 908 {
 909         struct seq_file *seq = file->private_data;
 910         struct proc_maps_private *priv = seq->private;
 911
 912         if (priv->mm)
 913                 mmdrop(priv->mm);
 914
 915         kfree(priv);
 916         return single_release(inode, file);
 917 }
 918
 919 const struct file_operations proc_pid_smaps_operations = {
 920         .open           = pid_smaps_open,
 921         .read           = seq_read,
 922         .llseek         = seq_lseek,
 923         .release        = proc_map_release,
 924 };
 925
 926 const struct file_operations proc_pid_smaps_rollup_operations = {
 927         .open           = smaps_rollup_open,
 928         .read           = seq_read,
 929         .llseek         = seq_lseek,
 930         .release        = smaps_rollup_release,
 931 };
 932
 933 enum clear_refs_types {
 934         CLEAR_REFS_ALL = 1,
 935         CLEAR_REFS_ANON,
 936         CLEAR_REFS_MAPPED,
 937         CLEAR_REFS_SOFT_DIRTY,
 938         CLEAR_REFS_MM_HIWATER_RSS,
 939         CLEAR_REFS_LAST,
 940 };
 941
 942 struct clear_refs_private {
 943         enum clear_refs_types type;
 944 };
 945
 946 #ifdef CONFIG_MEM_SOFT_DIRTY
 947 static inline void clear_soft_dirty(struct vm_area_struct *vma,
 948                 unsigned long addr, pte_t *pte)
 949 {
 950         /*
 951          * The soft-dirty tracker uses #PF-s to catch writes
 952          * to pages, so write-protect the pte as well. See the
 953          * Documentation/admin-guide/mm/soft-dirty.rst for full description
 954          * of how soft-dirty works.
 955          */
 956         pte_t ptent = *pte;
 957
 958         if (pte_present(ptent)) {
 959                 ptent = ptep_modify_prot_start(vma->vm_mm, addr, pte);
 960                 ptent = pte_wrprotect(ptent);
 961                 ptent = pte_clear_soft_dirty(ptent);
 962                 ptep_modify_prot_commit(vma->vm_mm, addr, pte, ptent);
 963         } else if (is_swap_pte(ptent)) {
 964                 ptent = pte_swp_clear_soft_dirty(ptent);
 965                 set_pte_at(vma->vm_mm, addr, pte, ptent);
 966         }
 967 }
 968 #else
 969 static inline void clear_soft_dirty(struct vm_area_struct *vma,
 970                 unsigned long addr, pte_t *pte)
 971 {
 972 }
 973 #endif
 974
 975 #if defined(CONFIG_MEM_SOFT_DIRTY) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 976 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
 977                 unsigned long addr, pmd_t *pmdp)
 978 {
 979         pmd_t old, pmd = *pmdp;
 980
 981         if (pmd_present(pmd)) {
 982                 /* See comment in change_huge_pmd() */
 983                 old = pmdp_invalidate(vma, addr, pmdp);
 984                 if (pmd_dirty(old))
 985                         pmd = pmd_mkdirty(pmd);
 986                 if (pmd_young(old))
 987                         pmd = pmd_mkyoung(pmd);
 988
 989                 pmd = pmd_wrprotect(pmd);
 990                 pmd = pmd_clear_soft_dirty(pmd);
 991
 992                 set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
 993         } else if (is_migration_entry(pmd_to_swp_entry(pmd))) {
 994                 pmd = pmd_swp_clear_soft_dirty(pmd);
 995                 set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
 996         }
 997 }
 998 #else
 999 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
1000                 unsigned long addr, pmd_t *pmdp)
1001 {
1002 }
1003 #endif
1004
1005 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
1006                                 unsigned long end, struct mm_walk *walk)
1007 {
1008         struct clear_refs_private *cp = walk->private;
1009         struct vm_area_struct *vma = walk->vma;
1010         pte_t *pte, ptent;
1011         spinlock_t *ptl;
1012         struct page *page;
1013
1014         ptl = pmd_trans_huge_lock(pmd, vma);
1015         if (ptl) {
1016                 if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
1017                         clear_soft_dirty_pmd(vma, addr, pmd);
1018                         goto out;
1019                 }
1020
1021                 if (!pmd_present(*pmd))
1022                         goto out;
1023
1024                 page = pmd_page(*pmd);
1025
1026                 /* Clear accessed and referenced bits. */
1027                 pmdp_test_and_clear_young(vma, addr, pmd);
1028                 test_and_clear_page_young(page);
1029                 ClearPageReferenced(page);
1030 out:
1031                 spin_unlock(ptl);
1032                 return 0;
1033         }
1034
1035         if (pmd_trans_unstable(pmd))
1036                 return 0;
1037
1038         pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
1039         for (; addr != end; pte++, addr += PAGE_SIZE) {
1040                 ptent = *pte;
1041
1042                 if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
1043                         clear_soft_dirty(vma, addr, pte);
1044                         continue;
1045                 }
1046
1047                 if (!pte_present(ptent))
1048                         continue;
1049
1050                 page = vm_normal_page(vma, addr, ptent);
1051                 if (!page)
1052                         continue;
1053
1054                 /* Clear accessed and referenced bits. */
1055                 ptep_test_and_clear_young(vma, addr, pte);
1056                 test_and_clear_page_young(page);
1057                 ClearPageReferenced(page);
1058         }
1059         pte_unmap_unlock(pte - 1, ptl);
1060         cond_resched();
1061         return 0;
1062 }
1063
1064 static int clear_refs_test_walk(unsigned long start, unsigned long end,
1065                                 struct mm_walk *walk)
1066 {
1067         struct clear_refs_private *cp = walk->private;
1068         struct vm_area_struct *vma = walk->vma;
1069
1070         if (vma->vm_flags & VM_PFNMAP)
1071                 return 1;
1072
1073         /*
1074          * Writing 1 to /proc/pid/clear_refs affects all pages.
1075          * Writing 2 to /proc/pid/clear_refs only affects anonymous pages.
1076          * Writing 3 to /proc/pid/clear_refs only affects file mapped pages.
1077          * Writing 4 to /proc/pid/clear_refs affects all pages.
1078          */
1079         if (cp->type == CLEAR_REFS_ANON && vma->vm_file)
1080                 return 1;
1081         if (cp->type == CLEAR_REFS_MAPPED && !vma->vm_file)
1082                 return 1;
1083         return 0;
1084 }
1085
1086 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
1087                                 size_t count, loff_t *ppos)
1088 {
1089         struct task_struct *task;
1090         char buffer[PROC_NUMBUF];
1091         struct mm_struct *mm;
1092         struct vm_area_struct *vma;
1093         enum clear_refs_types type;
1094         struct mmu_gather tlb;
1095         int itype;
1096         int rv;
1097
1098         memset(buffer, 0, sizeof(buffer));
1099         if (count > sizeof(buffer) - 1)
1100                 count = sizeof(buffer) - 1;
1101         if (copy_from_user(buffer, buf, count))
1102                 return -EFAULT;
1103         rv = kstrtoint(strstrip(buffer), 10, &itype);
1104         if (rv < 0)
1105                 return rv;
1106         type = (enum clear_refs_types)itype;
1107         if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
1108                 return -EINVAL;
1109
1110         task = get_proc_task(file_inode(file));
1111         if (!task)
1112                 return -ESRCH;
1113         mm = get_task_mm(task);
1114         if (mm) {
1115                 struct clear_refs_private cp = {
1116                         .type = type,
1117                 };
1118                 struct mm_walk clear_refs_walk = {
1119                         .pmd_entry = clear_refs_pte_range,
1120                         .test_walk = clear_refs_test_walk,
1121                         .mm = mm,
1122                         .private = &cp,
1123                 };
1124
1125                 if (type == CLEAR_REFS_MM_HIWATER_RSS) {
1126                         if (down_write_killable(&mm->mmap_sem)) {
1127                                 count = -EINTR;
1128                                 goto out_mm;
1129                         }
1130
1131                         /*
1132                          * Writing 5 to /proc/pid/clear_refs resets the peak
1133                          * resident set size to this mm's current rss value.
1134                          */
1135                         reset_mm_hiwater_rss(mm);
1136                         up_write(&mm->mmap_sem);
1137                         goto out_mm;
1138                 }
1139
1140                 if (down_read_killable(&mm->mmap_sem)) {
1141                         count = -EINTR;
1142                         goto out_mm;
1143                 }
1144                 tlb_gather_mmu(&tlb, mm, 0, -1);
1145                 if (type == CLEAR_REFS_SOFT_DIRTY) {
1146                         for (vma = mm->mmap; vma; vma = vma->vm_next) {
1147                                 if (!(vma->vm_flags & VM_SOFTDIRTY))
1148                                         continue;
1149                                 up_read(&mm->mmap_sem);
1150                                 if (down_write_killable(&mm->mmap_sem)) {
1151                                         count = -EINTR;
1152                                         goto out_mm;
1153                                 }
1154                                 /*
1155                                  * Avoid to modify vma->vm_flags
1156                                  * without locked ops while the
1157                                  * coredump reads the vm_flags.
1158                                  */
1159                                 if (!mmget_still_valid(mm)) {
1160                                         /*
1161                                          * Silently return "count"
1162                                          * like if get_task_mm()
1163                                          * failed. FIXME: should this
1164                                          * function have returned
1165                                          * -ESRCH if get_task_mm()
1166                                          * failed like if
1167                                          * get_proc_task() fails?
1168                                          */
1169                                         up_write(&mm->mmap_sem);
1170                                         goto out_mm;
1171                                 }
1172                                 for (vma = mm->mmap; vma; vma = vma->vm_next) {
1173                                         vma->vm_flags &= ~VM_SOFTDIRTY;
1174                                         vma_set_page_prot(vma);
1175                                 }
1176                                 downgrade_write(&mm->mmap_sem);
1177                                 break;
1178                         }
1179                         mmu_notifier_invalidate_range_start(mm, 0, -1);
1180                 }
1181                 walk_page_range(0, mm->highest_vm_end, &clear_refs_walk);
1182                 if (type == CLEAR_REFS_SOFT_DIRTY)
1183                         mmu_notifier_invalidate_range_end(mm, 0, -1);
1184                 tlb_finish_mmu(&tlb, 0, -1);
1185                 up_read(&mm->mmap_sem);
1186 out_mm:
1187                 mmput(mm);
1188         }
1189         put_task_struct(task);
1190
1191         return count;
1192 }
1193
1194 const struct file_operations proc_clear_refs_operations = {
1195         .write          = clear_refs_write,
1196         .llseek         = noop_llseek,
1197 };
1198
1199 typedef struct {
1200         u64 pme;
1201 } pagemap_entry_t;
1202
1203 struct pagemapread {
1204         int pos, len;           /* units: PM_ENTRY_BYTES, not bytes */
1205         pagemap_entry_t *buffer;
1206         bool show_pfn;
1207 };
1208
1209 #define PAGEMAP_WALK_SIZE       (PMD_SIZE)
1210 #define PAGEMAP_WALK_MASK       (PMD_MASK)
1211
1212 #define PM_ENTRY_BYTES          sizeof(pagemap_entry_t)
1213 #define PM_PFRAME_BITS          55
1214 #define PM_PFRAME_MASK          GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
1215 #define PM_SOFT_DIRTY           BIT_ULL(55)
1216 #define PM_MMAP_EXCLUSIVE       BIT_ULL(56)
1217 #define PM_FILE                 BIT_ULL(61)
1218 #define PM_SWAP                 BIT_ULL(62)
1219 #define PM_PRESENT              BIT_ULL(63)
1220
1221 #define PM_END_OF_BUFFER    1
1222
1223 static inline pagemap_entry_t make_pme(u64 frame, u64 flags)
1224 {
1225         return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags };
1226 }
1227
1228 static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,
1229                           struct pagemapread *pm)
1230 {
1231         pm->buffer[pm->pos++] = *pme;
1232         if (pm->pos >= pm->len)
1233                 return PM_END_OF_BUFFER;
1234         return 0;
1235 }
1236
1237 static int pagemap_pte_hole(unsigned long start, unsigned long end,
1238                                 struct mm_walk *walk)
1239 {
1240         struct pagemapread *pm = walk->private;
1241         unsigned long addr = start;
1242         int err = 0;
1243
1244         while (addr < end) {
1245                 struct vm_area_struct *vma = find_vma(walk->mm, addr);
1246                 pagemap_entry_t pme = make_pme(0, 0);
1247                 /* End of address space hole, which we mark as non-present. */
1248                 unsigned long hole_end;
1249
1250                 if (vma)
1251                         hole_end = min(end, vma->vm_start);
1252                 else
1253                         hole_end = end;
1254
1255                 for (; addr < hole_end; addr += PAGE_SIZE) {
1256                         err = add_to_pagemap(addr, &pme, pm);
1257                         if (err)
1258                                 goto out;
1259                 }
1260
1261                 if (!vma)
1262                         break;
1263
1264                 /* Addresses in the VMA. */
1265                 if (vma->vm_flags & VM_SOFTDIRTY)
1266                         pme = make_pme(0, PM_SOFT_DIRTY);
1267                 for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
1268                         err = add_to_pagemap(addr, &pme, pm);
1269                         if (err)
1270                                 goto out;
1271                 }
1272         }
1273 out:
1274         return err;
1275 }
1276
1277 static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
1278                 struct vm_area_struct *vma, unsigned long addr, pte_t pte)
1279 {
1280         u64 frame = 0, flags = 0;
1281         struct page *page = NULL;
1282
1283         if (pte_present(pte)) {
1284                 if (pm->show_pfn)
1285                         frame = pte_pfn(pte);
1286                 flags |= PM_PRESENT;
1287                 page = _vm_normal_page(vma, addr, pte, true);
1288                 if (pte_soft_dirty(pte))
1289                         flags |= PM_SOFT_DIRTY;
1290         } else if (is_swap_pte(pte)) {
1291                 swp_entry_t entry;
1292                 if (pte_swp_soft_dirty(pte))
1293                         flags |= PM_SOFT_DIRTY;
1294                 entry = pte_to_swp_entry(pte);
1295                 if (pm->show_pfn)
1296                         frame = swp_type(entry) |
1297                                 (swp_offset(entry) << MAX_SWAPFILES_SHIFT);
1298                 flags |= PM_SWAP;
1299                 if (is_migration_entry(entry))
1300                         page = migration_entry_to_page(entry);
1301
1302                 if (is_device_private_entry(entry))
1303                         page = device_private_entry_to_page(entry);
1304         }
1305
1306         if (page && !PageAnon(page))
1307                 flags |= PM_FILE;
1308         if (page && page_mapcount(page) == 1)
1309                 flags |= PM_MMAP_EXCLUSIVE;
1310         if (vma->vm_flags & VM_SOFTDIRTY)
1311                 flags |= PM_SOFT_DIRTY;
1312
1313         return make_pme(frame, flags);
1314 }
1315
1316 static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
1317                              struct mm_walk *walk)
1318 {
1319         struct vm_area_struct *vma = walk->vma;
1320         struct pagemapread *pm = walk->private;
1321         spinlock_t *ptl;
1322         pte_t *pte, *orig_pte;
1323         int err = 0;
1324
1325 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1326         ptl = pmd_trans_huge_lock(pmdp, vma);
1327         if (ptl) {
1328                 u64 flags = 0, frame = 0;
1329                 pmd_t pmd = *pmdp;
1330                 struct page *page = NULL;
1331
1332                 if (vma->vm_flags & VM_SOFTDIRTY)
1333                         flags |= PM_SOFT_DIRTY;
1334
1335                 if (pmd_present(pmd)) {
1336                         page = pmd_page(pmd);
1337
1338                         flags |= PM_PRESENT;
1339                         if (pmd_soft_dirty(pmd))
1340                                 flags |= PM_SOFT_DIRTY;
1341                         if (pm->show_pfn)
1342                                 frame = pmd_pfn(pmd) +
1343                                         ((addr & ~PMD_MASK) >> PAGE_SHIFT);
1344                 }
1345 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
1346                 else if (is_swap_pmd(pmd)) {
1347                         swp_entry_t entry = pmd_to_swp_entry(pmd);
1348                         unsigned long offset;
1349
1350                         if (pm->show_pfn) {
1351                                 offset = swp_offset(entry) +
1352                                         ((addr & ~PMD_MASK) >> PAGE_SHIFT);
1353                                 frame = swp_type(entry) |
1354                                         (offset << MAX_SWAPFILES_SHIFT);
1355                         }
1356                         flags |= PM_SWAP;
1357                         if (pmd_swp_soft_dirty(pmd))
1358                                 flags |= PM_SOFT_DIRTY;
1359                         VM_BUG_ON(!is_pmd_migration_entry(pmd));
1360                         page = migration_entry_to_page(entry);
1361                 }
1362 #endif
1363
1364                 if (page && page_mapcount(page) == 1)
1365                         flags |= PM_MMAP_EXCLUSIVE;
1366
1367                 for (; addr != end; addr += PAGE_SIZE) {
1368                         pagemap_entry_t pme = make_pme(frame, flags);
1369
1370                         err = add_to_pagemap(addr, &pme, pm);
1371                         if (err)
1372                                 break;
1373                         if (pm->show_pfn) {
1374                                 if (flags & PM_PRESENT)
1375                                         frame++;
1376                                 else if (flags & PM_SWAP)
1377                                         frame += (1 << MAX_SWAPFILES_SHIFT);
1378                         }
1379                 }
1380                 spin_unlock(ptl);
1381                 return err;
1382         }
1383
1384         if (pmd_trans_unstable(pmdp))
1385                 return 0;
1386 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1387
1388         /*
1389          * We can assume that @vma always points to a valid one and @end never
1390          * goes beyond vma->vm_end.
1391          */
1392         orig_pte = pte = pte_offset_map_lock(walk->mm, pmdp, addr, &ptl);
1393         for (; addr < end; pte++, addr += PAGE_SIZE) {
1394                 pagemap_entry_t pme;
1395
1396                 pme = pte_to_pagemap_entry(pm, vma, addr, *pte);
1397                 err = add_to_pagemap(addr, &pme, pm);
1398                 if (err)
1399                         break;
1400         }
1401         pte_unmap_unlock(orig_pte, ptl);
1402
1403         cond_resched();
1404
1405         return err;
1406 }
1407
1408 #ifdef CONFIG_HUGETLB_PAGE
1409 /* This function walks within one hugetlb entry in the single call */
1410 static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
1411                                  unsigned long addr, unsigned long end,
1412                                  struct mm_walk *walk)
1413 {
1414         struct pagemapread *pm = walk->private;
1415         struct vm_area_struct *vma = walk->vma;
1416         u64 flags = 0, frame = 0;
1417         int err = 0;
1418         pte_t pte;
1419
1420         if (vma->vm_flags & VM_SOFTDIRTY)
1421                 flags |= PM_SOFT_DIRTY;
1422
1423         pte = huge_ptep_get(ptep);
1424         if (pte_present(pte)) {
1425                 struct page *page = pte_page(pte);
1426
1427                 if (!PageAnon(page))
1428                         flags |= PM_FILE;
1429
1430                 if (page_mapcount(page) == 1)
1431                         flags |= PM_MMAP_EXCLUSIVE;
1432
1433                 flags |= PM_PRESENT;
1434                 if (pm->show_pfn)
1435                         frame = pte_pfn(pte) +
1436                                 ((addr & ~hmask) >> PAGE_SHIFT);
1437         }
1438
1439         for (; addr != end; addr += PAGE_SIZE) {
1440                 pagemap_entry_t pme = make_pme(frame, flags);
1441
1442                 err = add_to_pagemap(addr, &pme, pm);
1443                 if (err)
1444                         return err;
1445                 if (pm->show_pfn && (flags & PM_PRESENT))
1446                         frame++;
1447         }
1448
1449         cond_resched();
1450
1451         return err;
1452 }
1453 #endif /* HUGETLB_PAGE */
1454
1455 /*
1456  * /proc/pid/pagemap - an array mapping virtual pages to pfns
1457  *
1458  * For each page in the address space, this file contains one 64-bit entry
1459  * consisting of the following:
1460  *
1461  * Bits 0-54  page frame number (PFN) if present
1462  * Bits 0-4   swap type if swapped
1463  * Bits 5-54  swap offset if swapped
1464  * Bit  55    pte is soft-dirty (see Documentation/admin-guide/mm/soft-dirty.rst)
1465  * Bit  56    page exclusively mapped
1466  * Bits 57-60 zero
1467  * Bit  61    page is file-page or shared-anon
1468  * Bit  62    page swapped
1469  * Bit  63    page present
1470  *
1471  * If the page is not present but in swap, then the PFN contains an
1472  * encoding of the swap file number and the page's offset into the
1473  * swap. Unmapped pages return a null PFN. This allows determining
1474  * precisely which pages are mapped (or in swap) and comparing mapped
1475  * pages between processes.
1476  *
1477  * Efficient users of this interface will use /proc/pid/maps to
1478  * determine which areas of memory are actually mapped and llseek to
1479  * skip over unmapped regions.
1480  */
1481 static ssize_t pagemap_read(struct file *file, char __user *buf,
1482                             size_t count, loff_t *ppos)
1483 {
1484         struct mm_struct *mm = file->private_data;
1485         struct pagemapread pm;
1486         struct mm_walk pagemap_walk = {};
1487         unsigned long src;
1488         unsigned long svpfn;
1489         unsigned long start_vaddr;
1490         unsigned long end_vaddr;
1491         int ret = 0, copied = 0;
1492
1493         if (!mm || !mmget_not_zero(mm))
1494                 goto out;
1495
1496         ret = -EINVAL;
1497         /* file position must be aligned */
1498         if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES))
1499                 goto out_mm;
1500
1501         ret = 0;
1502         if (!count)
1503                 goto out_mm;
1504
1505         /* do not disclose physical addresses: attack vector */
1506         pm.show_pfn = file_ns_capable(file, &init_user_ns, CAP_SYS_ADMIN);
1507
1508         pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
1509         pm.buffer = kmalloc_array(pm.len, PM_ENTRY_BYTES, GFP_KERNEL);
1510         ret = -ENOMEM;
1511         if (!pm.buffer)
1512                 goto out_mm;
1513
1514         pagemap_walk.pmd_entry = pagemap_pmd_range;
1515         pagemap_walk.pte_hole = pagemap_pte_hole;
1516 #ifdef CONFIG_HUGETLB_PAGE
1517         pagemap_walk.hugetlb_entry = pagemap_hugetlb_range;
1518 #endif
1519         pagemap_walk.mm = mm;
1520         pagemap_walk.private = &pm;
1521
1522         src = *ppos;
1523         svpfn = src / PM_ENTRY_BYTES;
1524         start_vaddr = svpfn << PAGE_SHIFT;
1525         end_vaddr = mm->task_size;
1526
1527         /* watch out for wraparound */
1528         if (svpfn > mm->task_size >> PAGE_SHIFT)
1529                 start_vaddr = end_vaddr;
1530
1531         /*
1532          * The odds are that this will stop walking way
1533          * before end_vaddr, because the length of the
1534          * user buffer is tracked in "pm", and the walk
1535          * will stop when we hit the end of the buffer.
1536          */
1537         ret = 0;
1538         while (count && (start_vaddr < end_vaddr)) {
1539                 int len;
1540                 unsigned long end;
1541
1542                 pm.pos = 0;
1543                 end = (start_vaddr + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
1544                 /* overflow ? */
1545                 if (end < start_vaddr || end > end_vaddr)
1546                         end = end_vaddr;
1547                 ret = down_read_killable(&mm->mmap_sem);
1548                 if (ret)
1549                         goto out_free;
1550                 ret = walk_page_range(start_vaddr, end, &pagemap_walk);
1551                 up_read(&mm->mmap_sem);
1552                 start_vaddr = end;
1553
1554                 len = min(count, PM_ENTRY_BYTES * pm.pos);
1555                 if (copy_to_user(buf, pm.buffer, len)) {
1556                         ret = -EFAULT;
1557                         goto out_free;
1558                 }
1559                 copied += len;
1560                 buf += len;
1561                 count -= len;
1562         }
1563         *ppos += copied;
1564         if (!ret || ret == PM_END_OF_BUFFER)
1565                 ret = copied;
1566
1567 out_free:
1568         kfree(pm.buffer);
1569 out_mm:
1570         mmput(mm);
1571 out:
1572         return ret;
1573 }
1574
1575 static int pagemap_open(struct inode *inode, struct file *file)
1576 {
1577         struct mm_struct *mm;
1578
1579         mm = proc_mem_open(inode, PTRACE_MODE_READ);
1580         if (IS_ERR(mm))
1581                 return PTR_ERR(mm);
1582         file->private_data = mm;
1583         return 0;
1584 }
1585
1586 static int pagemap_release(struct inode *inode, struct file *file)
1587 {
1588         struct mm_struct *mm = file->private_data;
1589
1590         if (mm)
1591                 mmdrop(mm);
1592         return 0;
1593 }
1594
1595 const struct file_operations proc_pagemap_operations = {
1596         .llseek         = mem_lseek, /* borrow this */
1597         .read           = pagemap_read,
1598         .open           = pagemap_open,
1599         .release        = pagemap_release,
1600 };
1601 #endif /* CONFIG_PROC_PAGE_MONITOR */
1602
1603 #ifdef CONFIG_NUMA
1604
1605 struct numa_maps {
1606         unsigned long pages;
1607         unsigned long anon;
1608         unsigned long active;
1609         unsigned long writeback;
1610         unsigned long mapcount_max;
1611         unsigned long dirty;
1612         unsigned long swapcache;
1613         unsigned long node[MAX_NUMNODES];
1614 };
1615
1616 struct numa_maps_private {
1617         struct proc_maps_private proc_maps;
1618         struct numa_maps md;
1619 };
1620
1621 static void gather_stats(struct page *page, struct numa_maps *md, int pte_dirty,
1622                         unsigned long nr_pages)
1623 {
1624         int count = page_mapcount(page);
1625
1626         md->pages += nr_pages;
1627         if (pte_dirty || PageDirty(page))
1628                 md->dirty += nr_pages;
1629
1630         if (PageSwapCache(page))
1631                 md->swapcache += nr_pages;
1632
1633         if (PageActive(page) || PageUnevictable(page))
1634                 md->active += nr_pages;
1635
1636         if (PageWriteback(page))
1637                 md->writeback += nr_pages;
1638
1639         if (PageAnon(page))
1640                 md->anon += nr_pages;
1641
1642         if (count > md->mapcount_max)
1643                 md->mapcount_max = count;
1644
1645         md->node[page_to_nid(page)] += nr_pages;
1646 }
1647
1648 static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
1649                 unsigned long addr)
1650 {
1651         struct page *page;
1652         int nid;
1653
1654         if (!pte_present(pte))
1655                 return NULL;
1656
1657         page = vm_normal_page(vma, addr, pte);
1658         if (!page)
1659                 return NULL;
1660
1661         if (PageReserved(page))
1662                 return NULL;
1663
1664         nid = page_to_nid(page);
1665         if (!node_isset(nid, node_states[N_MEMORY]))
1666                 return NULL;
1667
1668         return page;
1669 }
1670
1671 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1672 static struct page *can_gather_numa_stats_pmd(pmd_t pmd,
1673                                               struct vm_area_struct *vma,
1674                                               unsigned long addr)
1675 {
1676         struct page *page;
1677         int nid;
1678
1679         if (!pmd_present(pmd))
1680                 return NULL;
1681
1682         page = vm_normal_page_pmd(vma, addr, pmd);
1683         if (!page)
1684                 return NULL;
1685
1686         if (PageReserved(page))
1687                 return NULL;
1688
1689         nid = page_to_nid(page);
1690         if (!node_isset(nid, node_states[N_MEMORY]))
1691                 return NULL;
1692
1693         return page;
1694 }
1695 #endif
1696
1697 static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
1698                 unsigned long end, struct mm_walk *walk)
1699 {
1700         struct numa_maps *md = walk->private;
1701         struct vm_area_struct *vma = walk->vma;
1702         spinlock_t *ptl;
1703         pte_t *orig_pte;
1704         pte_t *pte;
1705
1706 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1707         ptl = pmd_trans_huge_lock(pmd, vma);
1708         if (ptl) {
1709                 struct page *page;
1710
1711                 page = can_gather_numa_stats_pmd(*pmd, vma, addr);
1712                 if (page)
1713                         gather_stats(page, md, pmd_dirty(*pmd),
1714                                      HPAGE_PMD_SIZE/PAGE_SIZE);
1715                 spin_unlock(ptl);
1716                 return 0;
1717         }
1718
1719         if (pmd_trans_unstable(pmd))
1720                 return 0;
1721 #endif
1722         orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
1723         do {
1724                 struct page *page = can_gather_numa_stats(*pte, vma, addr);
1725                 if (!page)
1726                         continue;
1727                 gather_stats(page, md, pte_dirty(*pte), 1);
1728
1729         } while (pte++, addr += PAGE_SIZE, addr != end);
1730         pte_unmap_unlock(orig_pte, ptl);
1731         cond_resched();
1732         return 0;
1733 }
1734 #ifdef CONFIG_HUGETLB_PAGE
1735 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
1736                 unsigned long addr, unsigned long end, struct mm_walk *walk)
1737 {
1738         pte_t huge_pte = huge_ptep_get(pte);
1739         struct numa_maps *md;
1740         struct page *page;
1741
1742         if (!pte_present(huge_pte))
1743                 return 0;
1744
1745         page = pte_page(huge_pte);
1746         if (!page)
1747                 return 0;
1748
1749         md = walk->private;
1750         gather_stats(page, md, pte_dirty(huge_pte), 1);
1751         return 0;
1752 }
1753
1754 #else
1755 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
1756                 unsigned long addr, unsigned long end, struct mm_walk *walk)
1757 {
1758         return 0;
1759 }
1760 #endif
1761
1762 /*
1763  * Display pages allocated per node and memory policy via /proc.
1764  */
1765 static int show_numa_map(struct seq_file *m, void *v)
1766 {
1767         struct numa_maps_private *numa_priv = m->private;
1768         struct proc_maps_private *proc_priv = &numa_priv->proc_maps;
1769         struct vm_area_struct *vma = v;
1770         struct numa_maps *md = &numa_priv->md;
1771         struct file *file = vma->vm_file;
1772         struct mm_struct *mm = vma->vm_mm;
1773         struct mm_walk walk = {
1774                 .hugetlb_entry = gather_hugetlb_stats,
1775                 .pmd_entry = gather_pte_stats,
1776                 .private = md,
1777                 .mm = mm,
1778         };
1779         struct mempolicy *pol;
1780         char buffer[64];
1781         int nid;
1782
1783         if (!mm)
1784                 return 0;
1785
1786         /* Ensure we start with an empty set of numa_maps statistics. */
1787         memset(md, 0, sizeof(*md));
1788
1789         pol = __get_vma_policy(vma, vma->vm_start);
1790         if (pol) {
1791                 mpol_to_str(buffer, sizeof(buffer), pol);
1792                 mpol_cond_put(pol);
1793         } else {
1794                 mpol_to_str(buffer, sizeof(buffer), proc_priv->task_mempolicy);
1795         }
1796
1797         seq_printf(m, "%08lx %s", vma->vm_start, buffer);
1798
1799         if (file) {
1800                 seq_puts(m, " file=");
1801                 seq_file_path(m, file, "\n\t= ");
1802         } else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
1803                 seq_puts(m, " heap");
1804         } else if (is_stack(vma)) {
1805                 seq_puts(m, " stack");
1806         }
1807
1808         if (is_vm_hugetlb_page(vma))
1809                 seq_puts(m, " huge");
1810
1811         /* mmap_sem is held by m_start */
1812         walk_page_vma(vma, &walk);
1813
1814         if (!md->pages)
1815                 goto out;
1816
1817         if (md->anon)
1818                 seq_printf(m, " anon=%lu", md->anon);
1819
1820         if (md->dirty)
1821                 seq_printf(m, " dirty=%lu", md->dirty);
1822
1823         if (md->pages != md->anon && md->pages != md->dirty)
1824                 seq_printf(m, " mapped=%lu", md->pages);
1825
1826         if (md->mapcount_max > 1)
1827                 seq_printf(m, " mapmax=%lu", md->mapcount_max);
1828
1829         if (md->swapcache)
1830                 seq_printf(m, " swapcache=%lu", md->swapcache);
1831
1832         if (md->active < md->pages && !is_vm_hugetlb_page(vma))
1833                 seq_printf(m, " active=%lu", md->active);
1834
1835         if (md->writeback)
1836                 seq_printf(m, " writeback=%lu", md->writeback);
1837
1838         for_each_node_state(nid, N_MEMORY)
1839                 if (md->node[nid])
1840                         seq_printf(m, " N%d=%lu", nid, md->node[nid]);
1841
1842         seq_printf(m, " kernelpagesize_kB=%lu", vma_kernel_pagesize(vma) >> 10);
1843 out:
1844         seq_putc(m, '\n');
1845         m_cache_vma(m, vma);
1846         return 0;
1847 }
1848
1849 static const struct seq_operations proc_pid_numa_maps_op = {
1850         .start  = m_start,
1851         .next   = m_next,
1852         .stop   = m_stop,
1853         .show   = show_numa_map,
1854 };
1855
1856 static int pid_numa_maps_open(struct inode *inode, struct file *file)
1857 {
1858         return proc_maps_open(inode, file, &proc_pid_numa_maps_op,
1859                                 sizeof(struct numa_maps_private));
1860 }
1861
1862 const struct file_operations proc_pid_numa_maps_operations = {
1863         .open           = pid_numa_maps_open,
1864         .read           = seq_read,
1865         .llseek         = seq_lseek,
1866         .release        = proc_map_release,
1867 };
1868
1869 #endif /* CONFIG_NUMA */