aboutsummaryrefslogtreecommitdiff
path: root/fs/proc/page.c
blob: 767d95a6d1b1bfdd713226915fb20bcca921347d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
#include <linux/bootmem.h>
#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
#include "internal.h"

#define KPMSIZE sizeof(u64)
#define KPMMASK (KPMSIZE - 1)
/* /proc/kpagecount - an array exposing page counts
 *
 * Each entry is a u64 representing the corresponding
 * physical page count.
 */
static ssize_t kpagecount_read(struct file *file, char __user *buf,
			     size_t count, loff_t *ppos)
{
	u64 __user *out = (u64 __user *)buf;
	struct page *ppage;
	unsigned long src = *ppos;
	unsigned long pfn;
	ssize_t ret = 0;
	u64 pcount;

	pfn = src / KPMSIZE;
	count = min_t(size_t, count, (max_pfn * KPMSIZE) - src);
	if (src & KPMMASK || count & KPMMASK)
		return -EINVAL;

	while (count > 0) {
		ppage = NULL;
		if (pfn_valid(pfn))
			ppage = pfn_to_page(pfn);
		pfn++;
		if (!ppage)
			pcount = 0;
		else
			pcount = page_mapcount(ppage);

		if (put_user(pcount, out++)) {
			ret = -EFAULT;
			break;
		}

		count -= KPMSIZE;
	}

	*ppos += (char __user *)out - buf;
	if (!ret)
		ret = (char __user *)out - buf;
	return ret;
}

static const struct file_operations proc_kpagecount_operations = {
	.llseek = mem_lseek,
	.read = kpagecount_read,
};

/* /proc/kpageflags - an array exposing page flags
 *
 * Each entry is a u64 representing the corresponding
 * physical page flags.
 */

/* These macros are used to decouple internal flags from exported ones */

#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

#define kpf_copy_bit(flags, srcpos, dstpos) (((flags >> srcpos) & 1) << dstpos)

static ssize_t kpageflags_read(struct file *file, char __user *buf,
			     size_t count, loff_t *ppos)
{
	u64 __user *out = (u64 __user *)buf;
	struct page *ppage;
	unsigned long src = *ppos;
	unsigned long pfn;
	ssize_t ret = 0;
	u64 kflags, uflags;

	pfn = src / KPMSIZE;
	count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
	if (src & KPMMASK || count & KPMMASK)
		return -EINVAL;

	while (count > 0) {
		ppage = NULL;
		if (pfn_valid(pfn))
			ppage = pfn_to_page(pfn);
		pfn++;
		if (!ppage)
			kflags = 0;
		else
			kflags = ppage->flags;

		uflags = kpf_copy_bit(KPF_LOCKED, PG_locked, kflags) |
			kpf_copy_bit(kflags, KPF_ERROR, PG_error) |
			kpf_copy_bit(kflags, KPF_REFERENCED, PG_referenced) |
			kpf_copy_bit(kflags, KPF_UPTODATE, PG_uptodate) |
			kpf_copy_bit(kflags, KPF_DIRTY, PG_dirty) |
			kpf_copy_bit(kflags, KPF_LRU, PG_lru) |
			kpf_copy_bit(kflags, KPF_ACTIVE, PG_active) |
			kpf_copy_bit(kflags, KPF_SLAB, PG_slab) |
			kpf_copy_bit(kflags, KPF_WRITEBACK, PG_writeback) |
			kpf_copy_bit(kflags, KPF_RECLAIM, PG_reclaim) |
			kpf_copy_bit(kflags, KPF_BUDDY, PG_buddy);

		if (put_user(uflags, out++)) {
			ret = -EFAULT;
			break;
		}

		count -= KPMSIZE;
	}

	*ppos += (char __user *)out - buf;
	if (!ret)
		ret = (char __user *)out - buf;
	return ret;
}

static const struct file_operations proc_kpageflags_operations = {
	.llseek = mem_lseek,
	.read = kpageflags_read,
};

static int __init proc_page_init(void)
{
	proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
	proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
	return 0;
}
module_init(proc_page_init);