mm: move page-types.c from Documentation to tools/vm

tools/ is the better place for vm tools which are used by many people.
Moving them to tools also make them open to more users instead of hide in
Documentation folder.

This patch moves page-types.c to tools/vm/page-types.c.  Also add a
Makefile in tools/vm and fix two coding style problems: a) change const
arrary to 'const char * const', b) change a space to tab for indent.

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 1113 insertions, 0 deletions

diff --git a/tools/vm/Makefile b/tools/vm/Makefile
new file mode 100644
index 00000000000..3823d4b1fa7
--- /dev/null
+++ b/tools/vm/Makefile
@@ -0,0 +1,11 @@
+# Makefile for vm tools
+
+CC = $(CROSS_COMPILE)gcc
+CFLAGS = -Wall -Wextra
+
+all: page-types
+%: %.c
+	$(CC) $(CFLAGS) -o $@ $^
+
+clean:
+	$(RM) page-types
diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c
new file mode 100644
index 00000000000..7dab7b25b5c
--- /dev/null
+++ b/tools/vm/page-types.c
@@ -0,0 +1,1102 @@
+/*
+ * page-types: Tool for querying page flags
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should find a copy of v2 of the GNU General Public License somewhere on
+ * your Linux system; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Copyright (C) 2009 Intel corporation
+ *
+ * Authors: Wu Fengguang <fengguang.wu@intel.com>
+ */
+
+#define _LARGEFILE64_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 <sys/types.h>
+#include <sys/errno.h>
+#include <sys/fcntl.h>
+#include <sys/mount.h>
+#include <sys/statfs.h>
+#include "../../include/linux/magic.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      sizeof(uint64_t)
+#define PM_STATUS_BITS      3
+#define PM_STATUS_OFFSET    (64 - PM_STATUS_BITS)
+#define PM_STATUS_MASK      (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET)
+#define PM_STATUS(nr)       (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK)
+#define PM_PSHIFT_BITS      6
+#define PM_PSHIFT_OFFSET    (PM_STATUS_OFFSET - PM_PSHIFT_BITS)
+#define PM_PSHIFT_MASK      (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET)
+#define PM_PSHIFT(x)        (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
+#define PM_PFRAME_MASK      ((1LL << PM_PSHIFT_OFFSET) - 1)
+#define PM_PFRAME(x)        ((x) & PM_PFRAME_MASK)
+
+#define PM_PRESENT          PM_STATUS(4LL)
+#define PM_SWAP             PM_STATUS(2LL)
+
+
+/*
+ * kernel page flags
+ */
+
+#define KPF_BYTES		8
+#define PROC_KPAGEFLAGS		"/proc/kpageflags"
+
+/* copied from kpageflags_read() */
+#define KPF_LOCKED		0
+#define KPF_ERROR		1
+#define KPF_REFERENCED		2
+#define KPF_UPTODATE		3
+#define KPF_DIRTY		4
+#define KPF_LRU			5
+#define KPF_ACTIVE		6
+#define KPF_SLAB		7
+#define KPF_WRITEBACK		8
+#define KPF_RECLAIM		9
+#define KPF_BUDDY		10
+
+/* [11-20] new additions in 2.6.31 */
+#define KPF_MMAP		11
+#define KPF_ANON		12
+#define KPF_SWAPCACHE		13
+#define KPF_SWAPBACKED		14
+#define KPF_COMPOUND_HEAD	15
+#define KPF_COMPOUND_TAIL	16
+#define KPF_HUGE		17
+#define KPF_UNEVICTABLE		18
+#define KPF_HWPOISON		19
+#define KPF_NOPAGE		20
+#define KPF_KSM			21
+#define KPF_THP			22
+
+/* [32-] kernel hacking assistances */
+#define KPF_RESERVED		32
+#define KPF_MLOCKED		33
+#define KPF_MAPPEDTODISK	34
+#define KPF_PRIVATE		35
+#define KPF_PRIVATE_2		36
+#define KPF_OWNER_PRIVATE	37
+#define KPF_ARCH		38
+#define KPF_UNCACHED		39
+
+/* [48-] take some arbitrary free slots for expanding overloaded flags
+ * not part of kernel API
+ */
+#define KPF_READAHEAD		48
+#define KPF_SLOB_FREE		49
+#define KPF_SLUB_FROZEN		50
+#define KPF_SLUB_DEBUG		51
+
+#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_RESERVED]		= "r:reserved",
+	[KPF_MLOCKED]		= "m:mlocked",
+	[KPF_MAPPEDTODISK]	= "d:mappedtodisk",
+	[KPF_PRIVATE]		= "P:private",
+	[KPF_PRIVATE_2]		= "p:private_2",
+	[KPF_OWNER_PRIVATE]	= "O:owner_private",
+	[KPF_ARCH]		= "h:arch",
+	[KPF_UNCACHED]		= "c:uncached",
+
+	[KPF_READAHEAD]		= "I:readahead",
+	[KPF_SLOB_FREE]		= "P:slob_free",
+	[KPF_SLUB_FROZEN]	= "A:slub_frozen",
+	[KPF_SLUB_DEBUG]	= "E:slub_debug",
+};
+
+
+static const char * const debugfs_known_mountpoints[] = {
+	"/sys/kernel/debug",
+	"/debug",
+	0,
+};
+
+/*
+ * data structures
+ */
+
+static int		opt_raw;	/* for kernel developers */
+static int		opt_list;	/* list pages (in ranges) */
+static int		opt_no_summary;	/* don't show summary */
+static pid_t		opt_pid;	/* process to walk */
+
+#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		opt_hwpoison;
+static int		opt_unpoison;
+
+static char		hwpoison_debug_fs[MAX_PATH+1];
+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, char *name,
+				 uint64_t *buf,
+				 unsigned long index,
+				 unsigned long count)
+{
+	long bytes;
+
+	if (index > ULONG_MAX / 8)
+		fatal("index overflow: %lu\n", index);
+
+	if (lseek(fd, index * 8, SEEK_SET) < 0) {
+		perror(name);
+		exit(EXIT_FAILURE);
+	}
+
+	bytes = read(fd, buf, count * 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, PROC_KPAGEFLAGS, 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;
+}
+
+
+/*
+ * page flag names
+ */
+
+static char *page_flag_name(uint64_t flags)
+{
+	static char buf[65];
+	int present;
+	int 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];
+	int 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, uint64_t flags)
+{
+	static uint64_t      flags0;
+	static unsigned long voff;
+	static unsigned long index;
+	static unsigned long count;
+
+	if (flags == flags0 && offset == index + count &&
+	    (!opt_pid || voffset == voff + count)) {
+		count++;
+		return;
+	}
+
+	if (count) {
+		if (opt_pid)
+			printf("%lx\t", voff);
+		printf("%lx\t%lx\t%s\n",
+				index, count, page_flag_name(flags0));
+	}
+
+	flags0 = flags;
+	index  = offset;
+	voff   = voffset;
+	count  = 1;
+}
+
+static void show_page(unsigned long voffset,
+		      unsigned long offset, uint64_t flags)
+{
+	if (opt_pid)
+		printf("%lx\t", voffset);
+	printf("%lx\t%s\n", offset, page_flag_name(flags));
+}
+
+static void show_summary(void)
+{
+	int 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)
+{
+	/* SLOB/SLUB overload several page flags */
+	if (flags & BIT(SLAB)) {
+		if (flags & BIT(PRIVATE))
+			flags ^= BIT(PRIVATE) | BIT(SLOB_FREE);
+		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);
+
+	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)
+{
+	flags = expand_overloaded_flags(flags);
+
+	if (!opt_raw)
+		flags = well_known_flags(flags);
+
+	return flags;
+}
+
+/* verify that a mountpoint is actually a debugfs instance */
+static int debugfs_valid_mountpoint(const char *debugfs)
+{
+	struct statfs st_fs;
+
+	if (statfs(debugfs, &st_fs) < 0)
+		return -ENOENT;
+	else if (st_fs.f_type != (long) DEBUGFS_MAGIC)
+		return -ENOENT;
+
+	return 0;
+}
+
+/* find the path to the mounted debugfs */
+static const char *debugfs_find_mountpoint(void)
+{
+	const char **ptr;
+	char type[100];
+	FILE *fp;
+
+	ptr = debugfs_known_mountpoints;
+	while (*ptr) {
+		if (debugfs_valid_mountpoint(*ptr) == 0) {
+			strcpy(hwpoison_debug_fs, *ptr);
+			return hwpoison_debug_fs;
+		}
+		ptr++;
+	}
+
+	/* give up and parse /proc/mounts */
+	fp = fopen("/proc/mounts", "r");
+	if (fp == NULL)
+		perror("Can't open /proc/mounts for read");
+
+	while (fscanf(fp, "%*s %"
+		      STR(MAX_PATH)
+		      "s %99s %*s %*d %*d\n",
+		      hwpoison_debug_fs, type) == 2) {
+		if (strcmp(type, "debugfs") == 0)
+			break;
+	}
+	fclose(fp);
+
+	if (strcmp(type, "debugfs") != 0)
+		return NULL;
+
+	return hwpoison_debug_fs;
+}
+
+/* mount the debugfs somewhere if it's not mounted */
+
+static void debugfs_mount(void)
+{
+	const char **ptr;
+
+	/* see if it's already mounted */
+	if (debugfs_find_mountpoint())
+		return;
+
+	ptr = debugfs_known_mountpoints;
+	while (*ptr) {
+		if (mount(NULL, *ptr, "debugfs", 0, NULL) == 0) {
+			/* save the mountpoint */
+			strcpy(hwpoison_debug_fs, *ptr);
+			break;
+		}
+		ptr++;
+	}
+
+	if (*ptr == NULL) {
+		perror("mount debugfs");
+		exit(EXIT_FAILURE);
+	}
+}
+
+/*
+ * page actions
+ */
+
+static void prepare_hwpoison_fd(void)
+{
+	char buf[MAX_PATH + 1];
+
+	debugfs_mount();
+
+	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;
+}
+
+/*
+ * page frame walker
+ */
+
+static int hash_slot(uint64_t flags)
+{
+	int k = HASH_KEY(flags);
+	int 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)
+{
+	flags = kpageflags_flags(flags);
+
+	if (!bit_mask_ok(flags))
+		return;
+
+	if (opt_hwpoison)
+		hwpoison_page(offset);
+	if (opt_unpoison)
+		unpoison_page(offset);
+
+	if (opt_list == 1)
+		show_page_range(voffset, offset, flags);
+	else if (opt_list == 2)
+		show_page(voffset, offset, flags);
+
+	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 buf[KPAGEFLAGS_BATCH];
+	unsigned long batch;
+	long pages;
+	unsigned long i;
+
+	while (count) {
+		batch = min_t(unsigned long, count, KPAGEFLAGS_BATCH);
+		pages = kpageflags_read(buf, index, batch);
+		if (pages == 0)
+			break;
+
+		for (i = 0; i < pages; i++)
+			add_page(voffset + i, index + i, buf[i]);
+
+		index += pages;
+		count -= 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);
+		}
+
+		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(PROC_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(0, opt_offset[i], opt_size[i]);
+		else
+			walk_task(opt_offset[i], opt_size[i]);
+
+	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)
+{
+	int 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"
+"            -p|--pid     pid           Walk process address space\n"
+#if 0 /* planned features */
+"            -f|--file    filename      Walk file address space\n"
+#endif
+"            -l|--list                  Show page details in ranges\n"
+"            -L|--list-each             Show page details one by one\n"
+"            -N|--no-summary            Don't show summary info\n"
+"            -X|--hwpoison              hwpoison pages\n"
+"            -x|--unpoison              unpoison pages\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 parse_file(const char *name)
+{
+}
+
+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)
+{
+	int 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 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' },
+	{ "describe"  , 1, NULL, 'd' },
+	{ "list"      , 0, NULL, 'l' },
+	{ "list-each" , 0, NULL, 'L' },
+	{ "no-summary", 0, NULL, 'N' },
+	{ "hwpoison"  , 0, NULL, 'X' },
+	{ "unpoison"  , 0, NULL, 'x' },
+	{ "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:lLNXxh", 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 'd':
+			describe_flags(optarg);
+			exit(0);
+		case 'l':
+			opt_list = 1;
+			break;
+		case 'L':
+			opt_list = 2;
+			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 'h':
+			usage();
+			exit(0);
+		default:
+			usage();
+			exit(1);
+		}
+	}
+
+	if (opt_list && opt_pid)
+		printf("voffset\t");
+	if (opt_list == 1)
+		printf("offset\tlen\tflags\n");
+	if (opt_list == 2)
+		printf("offset\tflags\n");
+
+	walk_addr_ranges();
+
+	if (opt_list == 1)
+		show_page_range(0, 0, 0);  /* drain the buffer */
+
+	if (opt_no_summary)
+		return 0;
+
+	if (opt_list)
+		printf("\n\n");
+
+	show_summary();
+
+	return 0;
+}