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