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1#include <linux/bootmem.h>
2#include <linux/compiler.h>
3#include <linux/fs.h>
4#include <linux/init.h>
5#include <linux/ksm.h>
6#include <linux/mm.h>
7#include <linux/mmzone.h>
8#include <linux/proc_fs.h>
9#include <linux/seq_file.h>
10#include <linux/hugetlb.h>
11#include <linux/kernel-page-flags.h>
12#include <asm/uaccess.h>
13#include "internal.h"
14
15#define KPMSIZE sizeof(u64)
16#define KPMMASK (KPMSIZE - 1)
17
18/* /proc/kpagecount - an array exposing page counts
19 *
20 * Each entry is a u64 representing the corresponding
21 * physical page count.
22 */
23static ssize_t kpagecount_read(struct file *file, char __user *buf,
24 size_t count, loff_t *ppos)
25{
26 u64 __user *out = (u64 __user *)buf;
27 struct page *ppage;
28 unsigned long src = *ppos;
29 unsigned long pfn;
30 ssize_t ret = 0;
31 u64 pcount;
32
33 pfn = src / KPMSIZE;
34 count = min_t(size_t, count, (max_pfn * KPMSIZE) - src);
35 if (src & KPMMASK || count & KPMMASK)
36 return -EINVAL;
37
38 while (count > 0) {
39 if (pfn_valid(pfn))
40 ppage = pfn_to_page(pfn);
41 else
42 ppage = NULL;
43 if (!ppage || PageSlab(ppage))
44 pcount = 0;
45 else
46 pcount = page_mapcount(ppage);
47
48 if (put_user(pcount, out)) {
49 ret = -EFAULT;
50 break;
51 }
52
53 pfn++;
54 out++;
55 count -= KPMSIZE;
56 }
57
58 *ppos += (char __user *)out - buf;
59 if (!ret)
60 ret = (char __user *)out - buf;
61 return ret;
62}
63
64static const struct file_operations proc_kpagecount_operations = {
65 .llseek = mem_lseek,
66 .read = kpagecount_read,
67};
68
69/* /proc/kpageflags - an array exposing page flags
70 *
71 * Each entry is a u64 representing the corresponding
72 * physical page flags.
73 */
74
75static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
76{
77 return ((kflags >> kbit) & 1) << ubit;
78}
79
80u64 stable_page_flags(struct page *page)
81{
82 u64 k;
83 u64 u;
84
85 /*
86 * pseudo flag: KPF_NOPAGE
87 * it differentiates a memory hole from a page with no flags
88 */
89 if (!page)
90 return 1 << KPF_NOPAGE;
91
92 k = page->flags;
93 u = 0;
94
95 /*
96 * pseudo flags for the well known (anonymous) memory mapped pages
97 *
98 * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
99 * simple test in page_mapped() is not enough.
100 */
101 if (!PageSlab(page) && page_mapped(page))
102 u |= 1 << KPF_MMAP;
103 if (PageAnon(page))
104 u |= 1 << KPF_ANON;
105 if (PageKsm(page))
106 u |= 1 << KPF_KSM;
107
108 /*
109 * compound pages: export both head/tail info
110 * they together define a compound page's start/end pos and order
111 */
112 if (PageHead(page))
113 u |= 1 << KPF_COMPOUND_HEAD;
114 if (PageTail(page))
115 u |= 1 << KPF_COMPOUND_TAIL;
116 if (PageHuge(page))
117 u |= 1 << KPF_HUGE;
118
119 /*
120 * Caveats on high order pages: page->_count will only be set
121 * -1 on the head page; SLUB/SLQB do the same for PG_slab;
122 * SLOB won't set PG_slab at all on compound pages.
123 */
124 if (PageBuddy(page))
125 u |= 1 << KPF_BUDDY;
126
127 u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
128
129 u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
130
131 u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
132 u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
133 u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
134 u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
135
136 u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
137 u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
138 u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
139 u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
140
141 u |= kpf_copy_bit(k, KPF_SWAPCACHE, PG_swapcache);
142 u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
143
144 u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
145 u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked);
146
147#ifdef CONFIG_MEMORY_FAILURE
148 u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison);
149#endif
150
151#ifdef CONFIG_ARCH_USES_PG_UNCACHED
152 u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached);
153#endif
154
155 u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
156 u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
157 u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
158 u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
159 u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
160 u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
161
162 return u;
163};
164
165static ssize_t kpageflags_read(struct file *file, char __user *buf,
166 size_t count, loff_t *ppos)
167{
168 u64 __user *out = (u64 __user *)buf;
169 struct page *ppage;
170 unsigned long src = *ppos;
171 unsigned long pfn;
172 ssize_t ret = 0;
173
174 pfn = src / KPMSIZE;
175 count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
176 if (src & KPMMASK || count & KPMMASK)
177 return -EINVAL;
178
179 while (count > 0) {
180 if (pfn_valid(pfn))
181 ppage = pfn_to_page(pfn);
182 else
183 ppage = NULL;
184
185 if (put_user(stable_page_flags(ppage), out)) {
186 ret = -EFAULT;
187 break;
188 }
189
190 pfn++;
191 out++;
192 count -= KPMSIZE;
193 }
194
195 *ppos += (char __user *)out - buf;
196 if (!ret)
197 ret = (char __user *)out - buf;
198 return ret;
199}
200
201static const struct file_operations proc_kpageflags_operations = {
202 .llseek = mem_lseek,
203 .read = kpageflags_read,
204};
205
206static int __init proc_page_init(void)
207{
208 proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
209 proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
210 return 0;
211}
212module_init(proc_page_init);
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/memblock.h>
3#include <linux/compiler.h>
4#include <linux/fs.h>
5#include <linux/init.h>
6#include <linux/ksm.h>
7#include <linux/mm.h>
8#include <linux/mmzone.h>
9#include <linux/huge_mm.h>
10#include <linux/proc_fs.h>
11#include <linux/seq_file.h>
12#include <linux/hugetlb.h>
13#include <linux/memremap.h>
14#include <linux/memcontrol.h>
15#include <linux/mmu_notifier.h>
16#include <linux/page_idle.h>
17#include <linux/kernel-page-flags.h>
18#include <linux/uaccess.h>
19#include "internal.h"
20
21#define KPMSIZE sizeof(u64)
22#define KPMMASK (KPMSIZE - 1)
23#define KPMBITS (KPMSIZE * BITS_PER_BYTE)
24
25static inline unsigned long get_max_dump_pfn(void)
26{
27#ifdef CONFIG_SPARSEMEM
28 /*
29 * The memmap of early sections is completely populated and marked
30 * online even if max_pfn does not fall on a section boundary -
31 * pfn_to_online_page() will succeed on all pages. Allow inspecting
32 * these memmaps.
33 */
34 return round_up(max_pfn, PAGES_PER_SECTION);
35#else
36 return max_pfn;
37#endif
38}
39
40/* /proc/kpagecount - an array exposing page counts
41 *
42 * Each entry is a u64 representing the corresponding
43 * physical page count.
44 */
45static ssize_t kpagecount_read(struct file *file, char __user *buf,
46 size_t count, loff_t *ppos)
47{
48 const unsigned long max_dump_pfn = get_max_dump_pfn();
49 u64 __user *out = (u64 __user *)buf;
50 struct page *ppage;
51 unsigned long src = *ppos;
52 unsigned long pfn;
53 ssize_t ret = 0;
54 u64 pcount;
55
56 pfn = src / KPMSIZE;
57 if (src & KPMMASK || count & KPMMASK)
58 return -EINVAL;
59 if (src >= max_dump_pfn * KPMSIZE)
60 return 0;
61 count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
62
63 while (count > 0) {
64 /*
65 * TODO: ZONE_DEVICE support requires to identify
66 * memmaps that were actually initialized.
67 */
68 ppage = pfn_to_online_page(pfn);
69
70 if (!ppage || PageSlab(ppage) || page_has_type(ppage))
71 pcount = 0;
72 else
73 pcount = page_mapcount(ppage);
74
75 if (put_user(pcount, out)) {
76 ret = -EFAULT;
77 break;
78 }
79
80 pfn++;
81 out++;
82 count -= KPMSIZE;
83
84 cond_resched();
85 }
86
87 *ppos += (char __user *)out - buf;
88 if (!ret)
89 ret = (char __user *)out - buf;
90 return ret;
91}
92
93static const struct proc_ops kpagecount_proc_ops = {
94 .proc_flags = PROC_ENTRY_PERMANENT,
95 .proc_lseek = mem_lseek,
96 .proc_read = kpagecount_read,
97};
98
99/* /proc/kpageflags - an array exposing page flags
100 *
101 * Each entry is a u64 representing the corresponding
102 * physical page flags.
103 */
104
105static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
106{
107 return ((kflags >> kbit) & 1) << ubit;
108}
109
110u64 stable_page_flags(struct page *page)
111{
112 u64 k;
113 u64 u;
114
115 /*
116 * pseudo flag: KPF_NOPAGE
117 * it differentiates a memory hole from a page with no flags
118 */
119 if (!page)
120 return 1 << KPF_NOPAGE;
121
122 k = page->flags;
123 u = 0;
124
125 /*
126 * pseudo flags for the well known (anonymous) memory mapped pages
127 *
128 * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
129 * simple test in page_mapped() is not enough.
130 */
131 if (!PageSlab(page) && page_mapped(page))
132 u |= 1 << KPF_MMAP;
133 if (PageAnon(page))
134 u |= 1 << KPF_ANON;
135 if (PageKsm(page))
136 u |= 1 << KPF_KSM;
137
138 /*
139 * compound pages: export both head/tail info
140 * they together define a compound page's start/end pos and order
141 */
142 if (PageHead(page))
143 u |= 1 << KPF_COMPOUND_HEAD;
144 if (PageTail(page))
145 u |= 1 << KPF_COMPOUND_TAIL;
146 if (PageHuge(page))
147 u |= 1 << KPF_HUGE;
148 /*
149 * PageTransCompound can be true for non-huge compound pages (slab
150 * pages or pages allocated by drivers with __GFP_COMP) because it
151 * just checks PG_head/PG_tail, so we need to check PageLRU/PageAnon
152 * to make sure a given page is a thp, not a non-huge compound page.
153 */
154 else if (PageTransCompound(page)) {
155 struct page *head = compound_head(page);
156
157 if (PageLRU(head) || PageAnon(head))
158 u |= 1 << KPF_THP;
159 else if (is_huge_zero_page(head)) {
160 u |= 1 << KPF_ZERO_PAGE;
161 u |= 1 << KPF_THP;
162 }
163 } else if (is_zero_pfn(page_to_pfn(page)))
164 u |= 1 << KPF_ZERO_PAGE;
165
166
167 /*
168 * Caveats on high order pages: page->_refcount will only be set
169 * -1 on the head page; SLUB/SLQB do the same for PG_slab;
170 * SLOB won't set PG_slab at all on compound pages.
171 */
172 if (PageBuddy(page))
173 u |= 1 << KPF_BUDDY;
174 else if (page_count(page) == 0 && is_free_buddy_page(page))
175 u |= 1 << KPF_BUDDY;
176
177 if (PageOffline(page))
178 u |= 1 << KPF_OFFLINE;
179 if (PageTable(page))
180 u |= 1 << KPF_PGTABLE;
181
182 if (page_is_idle(page))
183 u |= 1 << KPF_IDLE;
184
185 u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
186
187 u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
188 if (PageTail(page) && PageSlab(compound_head(page)))
189 u |= 1 << KPF_SLAB;
190
191 u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
192 u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
193 u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
194 u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
195
196 u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
197 u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
198 u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
199 u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
200
201 if (PageSwapCache(page))
202 u |= 1 << KPF_SWAPCACHE;
203 u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
204
205 u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
206 u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked);
207
208#ifdef CONFIG_MEMORY_FAILURE
209 u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison);
210#endif
211
212#ifdef CONFIG_ARCH_USES_PG_UNCACHED
213 u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached);
214#endif
215
216 u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
217 u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
218 u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
219 u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
220 u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
221 u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
222#ifdef CONFIG_ARCH_USES_PG_ARCH_X
223 u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2);
224 u |= kpf_copy_bit(k, KPF_ARCH_3, PG_arch_3);
225#endif
226
227 return u;
228};
229
230static ssize_t kpageflags_read(struct file *file, char __user *buf,
231 size_t count, loff_t *ppos)
232{
233 const unsigned long max_dump_pfn = get_max_dump_pfn();
234 u64 __user *out = (u64 __user *)buf;
235 struct page *ppage;
236 unsigned long src = *ppos;
237 unsigned long pfn;
238 ssize_t ret = 0;
239
240 pfn = src / KPMSIZE;
241 if (src & KPMMASK || count & KPMMASK)
242 return -EINVAL;
243 if (src >= max_dump_pfn * KPMSIZE)
244 return 0;
245 count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
246
247 while (count > 0) {
248 /*
249 * TODO: ZONE_DEVICE support requires to identify
250 * memmaps that were actually initialized.
251 */
252 ppage = pfn_to_online_page(pfn);
253
254 if (put_user(stable_page_flags(ppage), out)) {
255 ret = -EFAULT;
256 break;
257 }
258
259 pfn++;
260 out++;
261 count -= KPMSIZE;
262
263 cond_resched();
264 }
265
266 *ppos += (char __user *)out - buf;
267 if (!ret)
268 ret = (char __user *)out - buf;
269 return ret;
270}
271
272static const struct proc_ops kpageflags_proc_ops = {
273 .proc_flags = PROC_ENTRY_PERMANENT,
274 .proc_lseek = mem_lseek,
275 .proc_read = kpageflags_read,
276};
277
278#ifdef CONFIG_MEMCG
279static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
280 size_t count, loff_t *ppos)
281{
282 const unsigned long max_dump_pfn = get_max_dump_pfn();
283 u64 __user *out = (u64 __user *)buf;
284 struct page *ppage;
285 unsigned long src = *ppos;
286 unsigned long pfn;
287 ssize_t ret = 0;
288 u64 ino;
289
290 pfn = src / KPMSIZE;
291 if (src & KPMMASK || count & KPMMASK)
292 return -EINVAL;
293 if (src >= max_dump_pfn * KPMSIZE)
294 return 0;
295 count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
296
297 while (count > 0) {
298 /*
299 * TODO: ZONE_DEVICE support requires to identify
300 * memmaps that were actually initialized.
301 */
302 ppage = pfn_to_online_page(pfn);
303
304 if (ppage)
305 ino = page_cgroup_ino(ppage);
306 else
307 ino = 0;
308
309 if (put_user(ino, out)) {
310 ret = -EFAULT;
311 break;
312 }
313
314 pfn++;
315 out++;
316 count -= KPMSIZE;
317
318 cond_resched();
319 }
320
321 *ppos += (char __user *)out - buf;
322 if (!ret)
323 ret = (char __user *)out - buf;
324 return ret;
325}
326
327static const struct proc_ops kpagecgroup_proc_ops = {
328 .proc_flags = PROC_ENTRY_PERMANENT,
329 .proc_lseek = mem_lseek,
330 .proc_read = kpagecgroup_read,
331};
332#endif /* CONFIG_MEMCG */
333
334static int __init proc_page_init(void)
335{
336 proc_create("kpagecount", S_IRUSR, NULL, &kpagecount_proc_ops);
337 proc_create("kpageflags", S_IRUSR, NULL, &kpageflags_proc_ops);
338#ifdef CONFIG_MEMCG
339 proc_create("kpagecgroup", S_IRUSR, NULL, &kpagecgroup_proc_ops);
340#endif
341 return 0;
342}
343fs_initcall(proc_page_init);