root/tools/mm/page-types.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * page-types: Tool for querying page flags
 *
 * Copyright (C) 2009 Intel corporation
 *
 * Authors: Wu Fengguang <fengguang.wu@intel.com>
 */

#define _FILE_OFFSET_BITS 64
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <stdarg.h>
#include <string.h>
#include <getopt.h>
#include <limits.h>
#include <assert.h>
#include <ftw.h>
#include <time.h>
#include <setjmp.h>
#include <signal.h>
#include <inttypes.h>
#include <sys/types.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/mount.h>
#include <sys/statfs.h>
#include <sys/mman.h>
#include "../../include/uapi/linux/magic.h"
#include "../../include/uapi/linux/kernel-page-flags.h"
#include <api/fs/fs.h>

#ifndef MAX_PATH
# define MAX_PATH 256
#endif

#ifndef STR
# define _STR(x) #x
# define STR(x) _STR(x)
#endif

/*
 * pagemap kernel ABI bits
 */

#define PM_ENTRY_BYTES          8
#define PM_PFRAME_BITS          55
#define PM_PFRAME_MASK          ((1LL << PM_PFRAME_BITS) - 1)
#define PM_PFRAME(x)            ((x) & PM_PFRAME_MASK)
#define MAX_SWAPFILES_SHIFT     5
#define PM_SWAP_OFFSET(x)       (((x) & PM_PFRAME_MASK) >> MAX_SWAPFILES_SHIFT)
#define PM_SOFT_DIRTY           (1ULL << 55)
#define PM_MMAP_EXCLUSIVE       (1ULL << 56)
#define PM_FILE                 (1ULL << 61)
#define PM_SWAP                 (1ULL << 62)
#define PM_PRESENT              (1ULL << 63)

/*
 * kernel page flags
 */

#define KPF_BYTES               8
#define PROC_KPAGEFLAGS         "/proc/kpageflags"
#define PROC_KPAGECOUNT         "/proc/kpagecount"
#define PROC_KPAGECGROUP        "/proc/kpagecgroup"

#define SYS_KERNEL_MM_PAGE_IDLE "/sys/kernel/mm/page_idle/bitmap"

/* [32-] kernel hacking assistances */
#define KPF_RESERVED            32
#define KPF_MLOCKED             33
#define KPF_OWNER_2             34
#define KPF_PRIVATE             35
#define KPF_PRIVATE_2           36
#define KPF_OWNER_PRIVATE       37
#define KPF_ARCH                38
#define KPF_UNCACHED            39      /* unused */
#define KPF_SOFTDIRTY           40
#define KPF_ARCH_2              41

/* [47-] take some arbitrary free slots for expanding overloaded flags
 * not part of kernel API
 */
#define KPF_ANON_EXCLUSIVE      47
#define KPF_READAHEAD           48
#define KPF_SLUB_FROZEN         50
#define KPF_SLUB_DEBUG          51
#define KPF_FILE                61
#define KPF_SWAP                62
#define KPF_MMAP_EXCLUSIVE      63

#define KPF_ALL_BITS            ((uint64_t)~0ULL)
#define KPF_HACKERS_BITS        (0xffffULL << 32)
#define KPF_OVERLOADED_BITS     (0xffffULL << 48)
#define BIT(name)               (1ULL << KPF_##name)
#define BITS_COMPOUND           (BIT(COMPOUND_HEAD) | BIT(COMPOUND_TAIL))

static const char * const page_flag_names[] = {
        [KPF_LOCKED]            = "L:locked",
        [KPF_ERROR]             = "E:error",
        [KPF_REFERENCED]        = "R:referenced",
        [KPF_UPTODATE]          = "U:uptodate",
        [KPF_DIRTY]             = "D:dirty",
        [KPF_LRU]               = "l:lru",
        [KPF_ACTIVE]            = "A:active",
        [KPF_SLAB]              = "S:slab",
        [KPF_WRITEBACK]         = "W:writeback",
        [KPF_RECLAIM]           = "I:reclaim",
        [KPF_BUDDY]             = "B:buddy",

        [KPF_MMAP]              = "M:mmap",
        [KPF_ANON]              = "a:anonymous",
        [KPF_SWAPCACHE]         = "s:swapcache",
        [KPF_SWAPBACKED]        = "b:swapbacked",
        [KPF_COMPOUND_HEAD]     = "H:compound_head",
        [KPF_COMPOUND_TAIL]     = "T:compound_tail",
        [KPF_HUGE]              = "G:huge",
        [KPF_UNEVICTABLE]       = "u:unevictable",
        [KPF_HWPOISON]          = "X:hwpoison",
        [KPF_NOPAGE]            = "n:nopage",
        [KPF_KSM]               = "x:ksm",
        [KPF_THP]               = "t:thp",
        [KPF_OFFLINE]           = "o:offline",
        [KPF_PGTABLE]           = "g:pgtable",
        [KPF_ZERO_PAGE]         = "z:zero_page",
        [KPF_IDLE]              = "i:idle_page",

        [KPF_RESERVED]          = "r:reserved",
        [KPF_MLOCKED]           = "m:mlocked",
        [KPF_OWNER_2]           = "d:owner_2",
        [KPF_PRIVATE]           = "P:private",
        [KPF_PRIVATE_2]         = "p:private_2",
        [KPF_OWNER_PRIVATE]     = "O:owner_private",
        [KPF_ARCH]              = "h:arch",
        [KPF_SOFTDIRTY]         = "f:softdirty",
        [KPF_ARCH_2]            = "H:arch_2",

        [KPF_ANON_EXCLUSIVE]    = "d:anon_exclusive",
        [KPF_READAHEAD]         = "I:readahead",
        [KPF_SLUB_FROZEN]       = "A:slub_frozen",
        [KPF_SLUB_DEBUG]        = "E:slub_debug",

        [KPF_FILE]              = "F:file",
        [KPF_SWAP]              = "w:swap",
        [KPF_MMAP_EXCLUSIVE]    = "1:mmap_exclusive",
};


/*
 * data structures
 */

static int              opt_raw;        /* for kernel developers */
static int              opt_list;       /* list pages (in ranges) */
static int              opt_mark_idle;  /* set accessed bit */
static int              opt_no_summary; /* don't show summary */
static pid_t            opt_pid;        /* process to walk */
const char              *opt_file;      /* file or directory path */
static uint64_t         opt_cgroup;     /* cgroup inode */
static int              opt_list_cgroup;/* list page cgroup */
static int              opt_list_mapcnt;/* list page map count */
static const char       *opt_kpageflags;/* kpageflags file to parse */

#define MAX_ADDR_RANGES 1024
static int              nr_addr_ranges;
static unsigned long    opt_offset[MAX_ADDR_RANGES];
static unsigned long    opt_size[MAX_ADDR_RANGES];

#define MAX_VMAS        10240
static int              nr_vmas;
static unsigned long    pg_start[MAX_VMAS];
static unsigned long    pg_end[MAX_VMAS];

#define MAX_BIT_FILTERS 64
static int              nr_bit_filters;
static uint64_t         opt_mask[MAX_BIT_FILTERS];
static uint64_t         opt_bits[MAX_BIT_FILTERS];

static int              page_size;

static int              pagemap_fd;
static int              kpageflags_fd;
static int              kpagecount_fd = -1;
static int              kpagecgroup_fd = -1;
static int              page_idle_fd = -1;

static int              opt_hwpoison;
static int              opt_unpoison;

static const char       *hwpoison_debug_fs;
static int              hwpoison_inject_fd;
static int              hwpoison_forget_fd;

#define HASH_SHIFT      13
#define HASH_SIZE       (1 << HASH_SHIFT)
#define HASH_MASK       (HASH_SIZE - 1)
#define HASH_KEY(flags) (flags & HASH_MASK)

static unsigned long    total_pages;
static unsigned long    nr_pages[HASH_SIZE];
static uint64_t         page_flags[HASH_SIZE];


/*
 * helper functions
 */

#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

#define min_t(type, x, y) ({                    \
        type __min1 = (x);                      \
        type __min2 = (y);                      \
        __min1 < __min2 ? __min1 : __min2; })

#define max_t(type, x, y) ({                    \
        type __max1 = (x);                      \
        type __max2 = (y);                      \
        __max1 > __max2 ? __max1 : __max2; })

static unsigned long pages2mb(unsigned long pages)
{
        return (pages * page_size) >> 20;
}

static void fatal(const char *x, ...)
{
        va_list ap;

        va_start(ap, x);
        vfprintf(stderr, x, ap);
        va_end(ap);
        exit(EXIT_FAILURE);
}

static int checked_open(const char *pathname, int flags)
{
        int fd = open(pathname, flags);

        if (fd < 0) {
                perror(pathname);
                exit(EXIT_FAILURE);
        }

        return fd;
}

/*
 * pagemap/kpageflags routines
 */

static unsigned long do_u64_read(int fd, const char *name,
                                 uint64_t *buf,
                                 unsigned long index,
                                 unsigned long count)
{
        long bytes;

        if (index > ULONG_MAX / 8)
                fatal("index overflow: %lu\n", index);

        bytes = pread(fd, buf, count * 8, (off_t)index * 8);
        if (bytes < 0) {
                perror(name);
                exit(EXIT_FAILURE);
        }
        if (bytes % 8)
                fatal("partial read: %lu bytes\n", bytes);

        return bytes / 8;
}

static unsigned long kpageflags_read(uint64_t *buf,
                                     unsigned long index,
                                     unsigned long pages)
{
        return do_u64_read(kpageflags_fd, opt_kpageflags, buf, index, pages);
}

static unsigned long kpagecgroup_read(uint64_t *buf,
                                      unsigned long index,
                                      unsigned long pages)
{
        if (kpagecgroup_fd < 0)
                return pages;

        return do_u64_read(kpagecgroup_fd, opt_kpageflags, buf, index, pages);
}

static unsigned long kpagecount_read(uint64_t *buf,
                                     unsigned long index,
                                     unsigned long pages)
{
        return kpagecount_fd < 0 ? pages :
                do_u64_read(kpagecount_fd, PROC_KPAGECOUNT,
                            buf, index, pages);
}

static unsigned long pagemap_read(uint64_t *buf,
                                  unsigned long index,
                                  unsigned long pages)
{
        return do_u64_read(pagemap_fd, "/proc/pid/pagemap", buf, index, pages);
}

static unsigned long pagemap_pfn(uint64_t val)
{
        unsigned long pfn;

        if (val & PM_PRESENT)
                pfn = PM_PFRAME(val);
        else
                pfn = 0;

        return pfn;
}

static unsigned long pagemap_swap_offset(uint64_t val)
{
        return val & PM_SWAP ? PM_SWAP_OFFSET(val) : 0;
}

/*
 * page flag names
 */

static char *page_flag_name(uint64_t flags)
{
        static char buf[65];
        int present;
        size_t i, j;

        for (i = 0, j = 0; i < ARRAY_SIZE(page_flag_names); i++) {
                present = (flags >> i) & 1;
                if (!page_flag_names[i]) {
                        if (present)
                                fatal("unknown flag bit %d\n", i);
                        continue;
                }
                buf[j++] = present ? page_flag_names[i][0] : '_';
        }

        return buf;
}

static char *page_flag_longname(uint64_t flags)
{
        static char buf[1024];
        size_t i, n;

        for (i = 0, n = 0; i < ARRAY_SIZE(page_flag_names); i++) {
                if (!page_flag_names[i])
                        continue;
                if ((flags >> i) & 1)
                        n += snprintf(buf + n, sizeof(buf) - n, "%s,",
                                        page_flag_names[i] + 2);
        }
        if (n)
                n--;
        buf[n] = '\0';

        return buf;
}


/*
 * page list and summary
 */

static void show_page_range(unsigned long voffset, unsigned long offset,
                            unsigned long size, uint64_t flags,
                            uint64_t cgroup, uint64_t mapcnt)
{
        static uint64_t      flags0;
        static uint64_t      cgroup0;
        static uint64_t      mapcnt0;
        static unsigned long voff;
        static unsigned long index;
        static unsigned long count;

        if (flags == flags0 && cgroup == cgroup0 && mapcnt == mapcnt0 &&
            offset == index + count && size && voffset == voff + count) {
                count += size;
                return;
        }

        if (count) {
                if (opt_pid)
                        printf("%lx\t", voff);
                if (opt_file)
                        printf("%lx\t", voff);
                if (opt_list_cgroup)
                        printf("@%" PRIu64 "\t", cgroup0);
                if (opt_list_mapcnt)
                        printf("%" PRIu64 "\t", mapcnt0);
                printf("%lx\t%lx\t%s\n",
                                index, count, page_flag_name(flags0));
        }

        flags0 = flags;
        cgroup0 = cgroup;
        mapcnt0 = mapcnt;
        index  = offset;
        voff   = voffset;
        count  = size;
}

static void flush_page_range(void)
{
        show_page_range(0, 0, 0, 0, 0, 0);
}

static void show_page(unsigned long voffset, unsigned long offset,
                      uint64_t flags, uint64_t cgroup, uint64_t mapcnt)
{
        if (opt_pid)
                printf("%lx\t", voffset);
        if (opt_file)
                printf("%lx\t", voffset);
        if (opt_list_cgroup)
                printf("@%" PRIu64 "\t", cgroup);
        if (opt_list_mapcnt)
                printf("%" PRIu64 "\t", mapcnt);

        printf("%lx\t%s\n", offset, page_flag_name(flags));
}

static void show_summary(void)
{
        size_t i;

        printf("             flags\tpage-count       MB"
                "  symbolic-flags\t\t\tlong-symbolic-flags\n");

        for (i = 0; i < ARRAY_SIZE(nr_pages); i++) {
                if (nr_pages[i])
                        printf("0x%016llx\t%10lu %8lu  %s\t%s\n",
                                (unsigned long long)page_flags[i],
                                nr_pages[i],
                                pages2mb(nr_pages[i]),
                                page_flag_name(page_flags[i]),
                                page_flag_longname(page_flags[i]));
        }

        printf("             total\t%10lu %8lu\n",
                        total_pages, pages2mb(total_pages));
}


/*
 * page flag filters
 */

static int bit_mask_ok(uint64_t flags)
{
        int i;

        for (i = 0; i < nr_bit_filters; i++) {
                if (opt_bits[i] == KPF_ALL_BITS) {
                        if ((flags & opt_mask[i]) == 0)
                                return 0;
                } else {
                        if ((flags & opt_mask[i]) != opt_bits[i])
                                return 0;
                }
        }

        return 1;
}

static uint64_t expand_overloaded_flags(uint64_t flags, uint64_t pme)
{
        /* Anonymous pages use PG_owner_2 for anon_exclusive */
        if ((flags & BIT(ANON)) && (flags & BIT(OWNER_2)))
                flags ^= BIT(OWNER_2) | BIT(ANON_EXCLUSIVE);

        /* SLUB overloads several page flags */
        if (flags & BIT(SLAB)) {
                if (flags & BIT(ACTIVE))
                        flags ^= BIT(ACTIVE) | BIT(SLUB_FROZEN);
                if (flags & BIT(ERROR))
                        flags ^= BIT(ERROR) | BIT(SLUB_DEBUG);
        }

        /* PG_reclaim is overloaded as PG_readahead in the read path */
        if ((flags & (BIT(RECLAIM) | BIT(WRITEBACK))) == BIT(RECLAIM))
                flags ^= BIT(RECLAIM) | BIT(READAHEAD);

        if (pme & PM_SOFT_DIRTY)
                flags |= BIT(SOFTDIRTY);
        if (pme & PM_FILE)
                flags |= BIT(FILE);
        if (pme & PM_SWAP)
                flags |= BIT(SWAP);
        if (pme & PM_MMAP_EXCLUSIVE)
                flags |= BIT(MMAP_EXCLUSIVE);

        return flags;
}

static uint64_t well_known_flags(uint64_t flags)
{
        /* hide flags intended only for kernel hacker */
        flags &= ~KPF_HACKERS_BITS;

        /* hide non-hugeTLB compound pages */
        if ((flags & BITS_COMPOUND) && !(flags & BIT(HUGE)))
                flags &= ~BITS_COMPOUND;

        return flags;
}

static uint64_t kpageflags_flags(uint64_t flags, uint64_t pme)
{
        if (opt_raw)
                flags = expand_overloaded_flags(flags, pme);
        else
                flags = well_known_flags(flags);

        return flags;
}

/*
 * page actions
 */

static void prepare_hwpoison_fd(void)
{
        char buf[MAX_PATH + 1];

        hwpoison_debug_fs = debugfs__mount();
        if (!hwpoison_debug_fs) {
                perror("mount debugfs");
                exit(EXIT_FAILURE);
        }

        if (opt_hwpoison && !hwpoison_inject_fd) {
                snprintf(buf, MAX_PATH, "%s/hwpoison/corrupt-pfn",
                        hwpoison_debug_fs);
                hwpoison_inject_fd = checked_open(buf, O_WRONLY);
        }

        if (opt_unpoison && !hwpoison_forget_fd) {
                snprintf(buf, MAX_PATH, "%s/hwpoison/unpoison-pfn",
                        hwpoison_debug_fs);
                hwpoison_forget_fd = checked_open(buf, O_WRONLY);
        }
}

static int hwpoison_page(unsigned long offset)
{
        char buf[100];
        int len;

        len = sprintf(buf, "0x%lx\n", offset);
        len = write(hwpoison_inject_fd, buf, len);
        if (len < 0) {
                perror("hwpoison inject");
                return len;
        }
        return 0;
}

static int unpoison_page(unsigned long offset)
{
        char buf[100];
        int len;

        len = sprintf(buf, "0x%lx\n", offset);
        len = write(hwpoison_forget_fd, buf, len);
        if (len < 0) {
                perror("hwpoison forget");
                return len;
        }
        return 0;
}

static int mark_page_idle(unsigned long offset)
{
        static unsigned long off;
        static uint64_t buf;
        int len;

        if ((offset / 64 == off / 64) || buf == 0) {
                buf |= 1UL << (offset % 64);
                off = offset;
                return 0;
        }

        len = pwrite(page_idle_fd, &buf, 8, 8 * (off / 64));
        if (len < 0) {
                perror("mark page idle");
                return len;
        }

        buf = 1UL << (offset % 64);
        off = offset;

        return 0;
}

/*
 * page frame walker
 */

static size_t hash_slot(uint64_t flags)
{
        size_t k = HASH_KEY(flags);
        size_t i;

        /* Explicitly reserve slot 0 for flags 0: the following logic
         * cannot distinguish an unoccupied slot from slot (flags==0).
         */
        if (flags == 0)
                return 0;

        /* search through the remaining (HASH_SIZE-1) slots */
        for (i = 1; i < ARRAY_SIZE(page_flags); i++, k++) {
                if (!k || k >= ARRAY_SIZE(page_flags))
                        k = 1;
                if (page_flags[k] == 0) {
                        page_flags[k] = flags;
                        return k;
                }
                if (page_flags[k] == flags)
                        return k;
        }

        fatal("hash table full: bump up HASH_SHIFT?\n");
        exit(EXIT_FAILURE);
}

static void add_page(unsigned long voffset, unsigned long offset,
                     uint64_t flags, uint64_t cgroup, uint64_t mapcnt,
                     uint64_t pme)
{
        flags = kpageflags_flags(flags, pme);

        if (!bit_mask_ok(flags))
                return;

        if (opt_cgroup && cgroup != (uint64_t)opt_cgroup)
                return;

        if (opt_hwpoison)
                hwpoison_page(offset);
        if (opt_unpoison)
                unpoison_page(offset);

        if (opt_mark_idle)
                mark_page_idle(offset);

        if (opt_list == 1)
                show_page_range(voffset, offset, 1, flags, cgroup, mapcnt);
        else if (opt_list == 2)
                show_page(voffset, offset, flags, cgroup, mapcnt);

        nr_pages[hash_slot(flags)]++;
        total_pages++;
}

#define KPAGEFLAGS_BATCH        (64 << 10)      /* 64k pages */
static void walk_pfn(unsigned long voffset,
                     unsigned long index,
                     unsigned long count,
                     uint64_t pme)
{
        uint64_t buf[KPAGEFLAGS_BATCH];
        uint64_t cgi[KPAGEFLAGS_BATCH];
        uint64_t cnt[KPAGEFLAGS_BATCH];
        unsigned long batch;
        unsigned long pages;
        unsigned long i;

        /*
         * kpagecgroup_read() reads only if kpagecgroup were opened, but
         * /proc/kpagecgroup might even not exist, so it's better to fill
         * them with zeros here.
         */
        if (count == 1)
                cgi[0] = 0;
        else
                memset(cgi, 0, sizeof cgi);

        while (count) {
                batch = min_t(unsigned long, count, KPAGEFLAGS_BATCH);
                pages = kpageflags_read(buf, index, batch);
                if (pages == 0)
                        break;

                if (kpagecgroup_read(cgi, index, pages) != pages)
                        fatal("kpagecgroup returned fewer pages than expected");

                if (kpagecount_read(cnt, index, pages) != pages)
                        fatal("kpagecount returned fewer pages than expected");

                for (i = 0; i < pages; i++)
                        add_page(voffset + i, index + i,
                                 buf[i], cgi[i], cnt[i], pme);

                index += pages;
                count -= pages;
        }
}

static void walk_swap(unsigned long voffset, uint64_t pme)
{
        uint64_t flags = kpageflags_flags(0, pme);

        if (!bit_mask_ok(flags))
                return;

        if (opt_cgroup)
                return;

        if (opt_list == 1)
                show_page_range(voffset, pagemap_swap_offset(pme),
                                1, flags, 0, 0);
        else if (opt_list == 2)
                show_page(voffset, pagemap_swap_offset(pme), flags, 0, 0);

        nr_pages[hash_slot(flags)]++;
        total_pages++;
}

#define PAGEMAP_BATCH   (64 << 10)
static void walk_vma(unsigned long index, unsigned long count)
{
        uint64_t buf[PAGEMAP_BATCH];
        unsigned long batch;
        unsigned long pages;
        unsigned long pfn;
        unsigned long i;

        while (count) {
                batch = min_t(unsigned long, count, PAGEMAP_BATCH);
                pages = pagemap_read(buf, index, batch);
                if (pages == 0)
                        break;

                for (i = 0; i < pages; i++) {
                        pfn = pagemap_pfn(buf[i]);
                        if (pfn)
                                walk_pfn(index + i, pfn, 1, buf[i]);
                        if (buf[i] & PM_SWAP)
                                walk_swap(index + i, buf[i]);
                }

                index += pages;
                count -= pages;
        }
}

static void walk_task(unsigned long index, unsigned long count)
{
        const unsigned long end = index + count;
        unsigned long start;
        int i = 0;

        while (index < end) {

                while (pg_end[i] <= index)
                        if (++i >= nr_vmas)
                                return;
                if (pg_start[i] >= end)
                        return;

                start = max_t(unsigned long, pg_start[i], index);
                index = min_t(unsigned long, pg_end[i], end);

                assert(start < index);
                walk_vma(start, index - start);
        }
}

static void add_addr_range(unsigned long offset, unsigned long size)
{
        if (nr_addr_ranges >= MAX_ADDR_RANGES)
                fatal("too many addr ranges\n");

        opt_offset[nr_addr_ranges] = offset;
        opt_size[nr_addr_ranges] = min_t(unsigned long, size, ULONG_MAX-offset);
        nr_addr_ranges++;
}

static void walk_addr_ranges(void)
{
        int i;

        kpageflags_fd = checked_open(opt_kpageflags, O_RDONLY);

        if (!nr_addr_ranges)
                add_addr_range(0, ULONG_MAX);

        for (i = 0; i < nr_addr_ranges; i++)
                if (!opt_pid)
                        walk_pfn(opt_offset[i], opt_offset[i], opt_size[i], 0);
                else
                        walk_task(opt_offset[i], opt_size[i]);

        if (opt_mark_idle)
                mark_page_idle(0);

        close(kpageflags_fd);
}


/*
 * user interface
 */

static const char *page_flag_type(uint64_t flag)
{
        if (flag & KPF_HACKERS_BITS)
                return "(r)";
        if (flag & KPF_OVERLOADED_BITS)
                return "(o)";
        return "   ";
}

static void usage(void)
{
        size_t i, j;

        printf(
"page-types [options]\n"
"            -r|--raw                   Raw mode, for kernel developers\n"
"            -d|--describe flags        Describe flags\n"
"            -a|--addr    addr-spec     Walk a range of pages\n"
"            -b|--bits    bits-spec     Walk pages with specified bits\n"
"            -c|--cgroup  path|@inode   Walk pages within memory cgroup\n"
"            -p|--pid     pid           Walk process address space\n"
"            -f|--file    filename      Walk file address space\n"
"            -i|--mark-idle             Mark pages idle\n"
"            -l|--list                  Show page details in ranges\n"
"            -L|--list-each             Show page details one by one\n"
"            -C|--list-cgroup           Show cgroup inode for pages\n"
"            -M|--list-mapcnt           Show page map count\n"
"            -N|--no-summary            Don't show summary info\n"
"            -X|--hwpoison              hwpoison pages\n"
"            -x|--unpoison              unpoison pages\n"
"            -F|--kpageflags filename   kpageflags file to parse\n"
"            -h|--help                  Show this usage message\n"
"flags:\n"
"            0x10                       bitfield format, e.g.\n"
"            anon                       bit-name, e.g.\n"
"            0x10,anon                  comma-separated list, e.g.\n"
"addr-spec:\n"
"            N                          one page at offset N (unit: pages)\n"
"            N+M                        pages range from N to N+M-1\n"
"            N,M                        pages range from N to M-1\n"
"            N,                         pages range from N to end\n"
"            ,M                         pages range from 0 to M-1\n"
"bits-spec:\n"
"            bit1,bit2                  (flags & (bit1|bit2)) != 0\n"
"            bit1,bit2=bit1             (flags & (bit1|bit2)) == bit1\n"
"            bit1,~bit2                 (flags & (bit1|bit2)) == bit1\n"
"            =bit1,bit2                 flags == (bit1|bit2)\n"
"bit-names:\n"
        );

        for (i = 0, j = 0; i < ARRAY_SIZE(page_flag_names); i++) {
                if (!page_flag_names[i])
                        continue;
                printf("%16s%s", page_flag_names[i] + 2,
                                 page_flag_type(1ULL << i));
                if (++j > 3) {
                        j = 0;
                        putchar('\n');
                }
        }
        printf("\n                                   "
                "(r) raw mode bits  (o) overloaded bits\n");
}

static unsigned long long parse_number(const char *str)
{
        unsigned long long n;

        n = strtoll(str, NULL, 0);

        if (n == 0 && str[0] != '0')
                fatal("invalid name or number: %s\n", str);

        return n;
}

static void parse_pid(const char *str)
{
        FILE *file;
        char buf[5000];

        opt_pid = parse_number(str);

        sprintf(buf, "/proc/%d/pagemap", opt_pid);
        pagemap_fd = checked_open(buf, O_RDONLY);

        sprintf(buf, "/proc/%d/maps", opt_pid);
        file = fopen(buf, "r");
        if (!file) {
                perror(buf);
                exit(EXIT_FAILURE);
        }

        while (fgets(buf, sizeof(buf), file) != NULL) {
                unsigned long vm_start;
                unsigned long vm_end;
                unsigned long long pgoff;
                int major, minor;
                char r, w, x, s;
                unsigned long ino;
                int n;

                n = sscanf(buf, "%lx-%lx %c%c%c%c %llx %x:%x %lu",
                           &vm_start,
                           &vm_end,
                           &r, &w, &x, &s,
                           &pgoff,
                           &major, &minor,
                           &ino);
                if (n < 10) {
                        fprintf(stderr, "unexpected line: %s\n", buf);
                        continue;
                }
                pg_start[nr_vmas] = vm_start / page_size;
                pg_end[nr_vmas] = vm_end / page_size;
                if (++nr_vmas >= MAX_VMAS) {
                        fprintf(stderr, "too many VMAs\n");
                        break;
                }
        }
        fclose(file);
}

static void show_file(const char *name, const struct stat *st)
{
        unsigned long long size = st->st_size;
        char atime[64], mtime[64];
        long now = time(NULL);

        printf("%s\tInode: %u\tSize: %llu (%llu pages)\n",
                        name, (unsigned)st->st_ino,
                        size, (size + page_size - 1) / page_size);

        strftime(atime, sizeof(atime), "%c", localtime(&st->st_atime));
        strftime(mtime, sizeof(mtime), "%c", localtime(&st->st_mtime));

        printf("Modify: %s (%ld seconds ago)\nAccess: %s (%ld seconds ago)\n",
                        mtime, now - st->st_mtime,
                        atime, now - st->st_atime);
}

static sigjmp_buf sigbus_jmp;

static void * volatile sigbus_addr;

static void sigbus_handler(int sig, siginfo_t *info, void *ucontex)
{
        (void)sig;
        (void)ucontex;
        sigbus_addr = info ? info->si_addr : NULL;
        siglongjmp(sigbus_jmp, 1);
}

static struct sigaction sigbus_action = {
        .sa_sigaction = sigbus_handler,
        .sa_flags = SA_SIGINFO,
};

static void walk_file_range(const char *name, int fd,
                            unsigned long off, unsigned long end)
{
        uint8_t vec[PAGEMAP_BATCH];
        uint64_t buf[PAGEMAP_BATCH], flags;
        uint64_t cgroup = 0;
        uint64_t mapcnt = 0;
        unsigned long nr_pages, pfn, i;
        ssize_t len;
        void *ptr;
        int first = 1;

        for (; off < end; off += len) {
                nr_pages = (end - off + page_size - 1) / page_size;
                if (nr_pages > PAGEMAP_BATCH)
                        nr_pages = PAGEMAP_BATCH;
                len = nr_pages * page_size;

                ptr = mmap(NULL, len, PROT_READ, MAP_SHARED, fd, off);
                if (ptr == MAP_FAILED)
                        fatal("mmap failed: %s", name);

                /* determine cached pages */
                if (mincore(ptr, len, vec))
                        fatal("mincore failed: %s", name);

                /* turn off readahead */
                if (madvise(ptr, len, MADV_RANDOM))
                        fatal("madvice failed: %s", name);

                if (sigsetjmp(sigbus_jmp, 1)) {
                        end = off + sigbus_addr ? sigbus_addr - ptr : 0;
                        fprintf(stderr, "got sigbus at offset %lld: %s\n",
                                        (long long)end, name);
                        goto got_sigbus;
                }

                /* populate ptes */
                for (i = 0; i < nr_pages ; i++) {
                        if (vec[i] & 1)
                                (void)*(volatile int *)(ptr + i * page_size);
                }
got_sigbus:

                /* turn off harvesting reference bits */
                if (madvise(ptr, len, MADV_SEQUENTIAL))
                        fatal("madvice failed: %s", name);

                if (pagemap_read(buf, (unsigned long)ptr / page_size,
                                        nr_pages) != nr_pages)
                        fatal("cannot read pagemap");

                munmap(ptr, len);

                for (i = 0; i < nr_pages; i++) {
                        pfn = pagemap_pfn(buf[i]);
                        if (!pfn)
                                continue;
                        if (!kpageflags_read(&flags, pfn, 1))
                                continue;
                        if (!kpagecgroup_read(&cgroup, pfn, 1))
                                fatal("kpagecgroup_read failed");
                        if (!kpagecount_read(&mapcnt, pfn, 1))
                                fatal("kpagecount_read failed");
                        if (first && opt_list) {
                                first = 0;
                                flush_page_range();
                        }
                        add_page(off / page_size + i, pfn,
                                 flags, cgroup, mapcnt, buf[i]);
                }
        }
}

static void walk_file(const char *name, const struct stat *st)
{
        int i;
        int fd;

        fd = checked_open(name, O_RDONLY|O_NOATIME|O_NOFOLLOW);

        if (!nr_addr_ranges)
                add_addr_range(0, st->st_size / page_size);

        for (i = 0; i < nr_addr_ranges; i++)
                walk_file_range(name, fd, opt_offset[i] * page_size,
                                (opt_offset[i] + opt_size[i]) * page_size);

        close(fd);
}

int walk_tree(const char *name, const struct stat *st, int type, struct FTW *f)
{
        (void)f;
        switch (type) {
        case FTW_F:
                if (S_ISREG(st->st_mode))
                        walk_file(name, st);
                break;
        case FTW_DNR:
                fprintf(stderr, "cannot read dir: %s\n", name);
                break;
        }
        return 0;
}

struct stat st;

static void walk_page_cache(void)
{
        kpageflags_fd = checked_open(opt_kpageflags, O_RDONLY);
        pagemap_fd = checked_open("/proc/self/pagemap", O_RDONLY);
        sigaction(SIGBUS, &sigbus_action, NULL);

        if (stat(opt_file, &st))
                fatal("stat failed: %s\n", opt_file);

        if (S_ISREG(st.st_mode)) {
                walk_file(opt_file, &st);
        } else if (S_ISDIR(st.st_mode)) {
                /* do not follow symlinks and mountpoints */
                if (nftw(opt_file, walk_tree, 64, FTW_MOUNT | FTW_PHYS) < 0)
                        fatal("nftw failed: %s\n", opt_file);
        } else
                fatal("unhandled file type: %s\n", opt_file);

        close(kpageflags_fd);
        close(pagemap_fd);
        signal(SIGBUS, SIG_DFL);
}

static void parse_file(const char *name)
{
        opt_file = name;
}

static void parse_cgroup(const char *path)
{
        if (path[0] == '@') {
                opt_cgroup = parse_number(path + 1);
                return;
        }

        struct stat st;

        if (stat(path, &st))
                fatal("stat failed: %s: %m\n", path);

        if (!S_ISDIR(st.st_mode))
                fatal("cgroup supposed to be a directory: %s\n", path);

        opt_cgroup = st.st_ino;
}

static void parse_addr_range(const char *optarg)
{
        unsigned long offset;
        unsigned long size;
        char *p;

        p = strchr(optarg, ',');
        if (!p)
                p = strchr(optarg, '+');

        if (p == optarg) {
                offset = 0;
                size   = parse_number(p + 1);
        } else if (p) {
                offset = parse_number(optarg);
                if (p[1] == '\0')
                        size = ULONG_MAX;
                else {
                        size = parse_number(p + 1);
                        if (*p == ',') {
                                if (size < offset)
                                        fatal("invalid range: %lu,%lu\n",
                                                        offset, size);
                                size -= offset;
                        }
                }
        } else {
                offset = parse_number(optarg);
                size   = 1;
        }

        add_addr_range(offset, size);
}

static void add_bits_filter(uint64_t mask, uint64_t bits)
{
        if (nr_bit_filters >= MAX_BIT_FILTERS)
                fatal("too much bit filters\n");

        opt_mask[nr_bit_filters] = mask;
        opt_bits[nr_bit_filters] = bits;
        nr_bit_filters++;
}

static uint64_t parse_flag_name(const char *str, int len)
{
        size_t i;

        if (!*str || !len)
                return 0;

        if (len <= 8 && !strncmp(str, "compound", len))
                return BITS_COMPOUND;

        for (i = 0; i < ARRAY_SIZE(page_flag_names); i++) {
                if (!page_flag_names[i])
                        continue;
                if (!strncmp(str, page_flag_names[i] + 2, len))
                        return 1ULL << i;
        }

        return parse_number(str);
}

static uint64_t parse_flag_names(const char *str, int all)
{
        const char *p    = str;
        uint64_t   flags = 0;

        while (1) {
                if (*p == ',' || *p == '=' || *p == '\0') {
                        if ((*str != '~') || (*str == '~' && all && *++str))
                                flags |= parse_flag_name(str, p - str);
                        if (*p != ',')
                                break;
                        str = p + 1;
                }
                p++;
        }

        return flags;
}

static void parse_bits_mask(const char *optarg)
{
        uint64_t mask;
        uint64_t bits;
        const char *p;

        p = strchr(optarg, '=');
        if (p == optarg) {
                mask = KPF_ALL_BITS;
                bits = parse_flag_names(p + 1, 0);
        } else if (p) {
                mask = parse_flag_names(optarg, 0);
                bits = parse_flag_names(p + 1, 0);
        } else if (strchr(optarg, '~')) {
                mask = parse_flag_names(optarg, 1);
                bits = parse_flag_names(optarg, 0);
        } else {
                mask = parse_flag_names(optarg, 0);
                bits = KPF_ALL_BITS;
        }

        add_bits_filter(mask, bits);
}

static void parse_kpageflags(const char *name)
{
        opt_kpageflags = name;
}

static void describe_flags(const char *optarg)
{
        uint64_t flags = parse_flag_names(optarg, 0);

        printf("0x%016llx\t%s\t%s\n",
                (unsigned long long)flags,
                page_flag_name(flags),
                page_flag_longname(flags));
}

static const struct option opts[] = {
        { "raw"       , 0, NULL, 'r' },
        { "pid"       , 1, NULL, 'p' },
        { "file"      , 1, NULL, 'f' },
        { "addr"      , 1, NULL, 'a' },
        { "bits"      , 1, NULL, 'b' },
        { "cgroup"    , 1, NULL, 'c' },
        { "describe"  , 1, NULL, 'd' },
        { "mark-idle" , 0, NULL, 'i' },
        { "list"      , 0, NULL, 'l' },
        { "list-each" , 0, NULL, 'L' },
        { "list-cgroup", 0, NULL, 'C' },
        { "list-mapcnt", 0, NULL, 'M' },
        { "no-summary", 0, NULL, 'N' },
        { "hwpoison"  , 0, NULL, 'X' },
        { "unpoison"  , 0, NULL, 'x' },
        { "kpageflags", 0, NULL, 'F' },
        { "help"      , 0, NULL, 'h' },
        { NULL        , 0, NULL, 0 }
};

int main(int argc, char *argv[])
{
        int c;

        page_size = getpagesize();

        while ((c = getopt_long(argc, argv,
                                "rp:f:a:b:d:c:CilLMNXxF:h",
                                opts, NULL)) != -1) {
                switch (c) {
                case 'r':
                        opt_raw = 1;
                        break;
                case 'p':
                        parse_pid(optarg);
                        break;
                case 'f':
                        parse_file(optarg);
                        break;
                case 'a':
                        parse_addr_range(optarg);
                        break;
                case 'b':
                        parse_bits_mask(optarg);
                        break;
                case 'c':
                        parse_cgroup(optarg);
                        break;
                case 'C':
                        opt_list_cgroup = 1;
                        break;
                case 'd':
                        describe_flags(optarg);
                        exit(0);
                case 'i':
                        opt_mark_idle = 1;
                        break;
                case 'l':
                        opt_list = 1;
                        break;
                case 'L':
                        opt_list = 2;
                        break;
                case 'M':
                        opt_list_mapcnt = 1;
                        break;
                case 'N':
                        opt_no_summary = 1;
                        break;
                case 'X':
                        opt_hwpoison = 1;
                        prepare_hwpoison_fd();
                        break;
                case 'x':
                        opt_unpoison = 1;
                        prepare_hwpoison_fd();
                        break;
                case 'F':
                        parse_kpageflags(optarg);
                        break;
                case 'h':
                        usage();
                        exit(0);
                default:
                        usage();
                        exit(1);
                }
        }

        if (!opt_kpageflags)
                opt_kpageflags = PROC_KPAGEFLAGS;

        if (opt_cgroup || opt_list_cgroup)
                kpagecgroup_fd = checked_open(PROC_KPAGECGROUP, O_RDONLY);

        if (opt_list && opt_list_mapcnt)
                kpagecount_fd = checked_open(PROC_KPAGECOUNT, O_RDONLY);

        if (opt_mark_idle)
                page_idle_fd = checked_open(SYS_KERNEL_MM_PAGE_IDLE, O_RDWR);

        if (opt_list && opt_pid)
                printf("voffset\t");
        if (opt_list && opt_file)
                printf("foffset\t");
        if (opt_list && opt_list_cgroup)
                printf("cgroup\t");
        if (opt_list && opt_list_mapcnt)
                printf("map-cnt\t");

        if (opt_list == 1)
                printf("offset\tlen\tflags\n");
        if (opt_list == 2)
                printf("offset\tflags\n");

        if (opt_file)
                walk_page_cache();
        else
                walk_addr_ranges();

        if (opt_list == 1)
                flush_page_range();

        if (opt_no_summary)
                return 0;

        if (opt_list)
                printf("\n\n");

        if (opt_file) {
                show_file(opt_file, &st);
                printf("\n");
        }

        show_summary();

        if (opt_list_mapcnt)
                close(kpagecount_fd);

        if (page_idle_fd >= 0)
                close(page_idle_fd);

        return 0;
}