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