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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/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);
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/bootmem.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 if (pfn_valid(pfn))
46 ppage = pfn_to_page(pfn);
47 else
48 ppage = NULL;
49 if (!ppage || PageSlab(ppage))
50 pcount = 0;
51 else
52 pcount = page_mapcount(ppage);
53
54 if (put_user(pcount, out)) {
55 ret = -EFAULT;
56 break;
57 }
58
59 pfn++;
60 out++;
61 count -= KPMSIZE;
62
63 cond_resched();
64 }
65
66 *ppos += (char __user *)out - buf;
67 if (!ret)
68 ret = (char __user *)out - buf;
69 return ret;
70}
71
72static const struct file_operations proc_kpagecount_operations = {
73 .llseek = mem_lseek,
74 .read = kpagecount_read,
75};
76
77/* /proc/kpageflags - an array exposing page flags
78 *
79 * Each entry is a u64 representing the corresponding
80 * physical page flags.
81 */
82
83static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
84{
85 return ((kflags >> kbit) & 1) << ubit;
86}
87
88u64 stable_page_flags(struct page *page)
89{
90 u64 k;
91 u64 u;
92
93 /*
94 * pseudo flag: KPF_NOPAGE
95 * it differentiates a memory hole from a page with no flags
96 */
97 if (!page)
98 return 1 << KPF_NOPAGE;
99
100 k = page->flags;
101 u = 0;
102
103 /*
104 * pseudo flags for the well known (anonymous) memory mapped pages
105 *
106 * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
107 * simple test in page_mapped() is not enough.
108 */
109 if (!PageSlab(page) && page_mapped(page))
110 u |= 1 << KPF_MMAP;
111 if (PageAnon(page))
112 u |= 1 << KPF_ANON;
113 if (PageKsm(page))
114 u |= 1 << KPF_KSM;
115
116 /*
117 * compound pages: export both head/tail info
118 * they together define a compound page's start/end pos and order
119 */
120 if (PageHead(page))
121 u |= 1 << KPF_COMPOUND_HEAD;
122 if (PageTail(page))
123 u |= 1 << KPF_COMPOUND_TAIL;
124 if (PageHuge(page))
125 u |= 1 << KPF_HUGE;
126 /*
127 * PageTransCompound can be true for non-huge compound pages (slab
128 * pages or pages allocated by drivers with __GFP_COMP) because it
129 * just checks PG_head/PG_tail, so we need to check PageLRU/PageAnon
130 * to make sure a given page is a thp, not a non-huge compound page.
131 */
132 else if (PageTransCompound(page)) {
133 struct page *head = compound_head(page);
134
135 if (PageLRU(head) || PageAnon(head))
136 u |= 1 << KPF_THP;
137 else if (is_huge_zero_page(head)) {
138 u |= 1 << KPF_ZERO_PAGE;
139 u |= 1 << KPF_THP;
140 }
141 } else if (is_zero_pfn(page_to_pfn(page)))
142 u |= 1 << KPF_ZERO_PAGE;
143
144
145 /*
146 * Caveats on high order pages: page->_refcount will only be set
147 * -1 on the head page; SLUB/SLQB do the same for PG_slab;
148 * SLOB won't set PG_slab at all on compound pages.
149 */
150 if (PageBuddy(page))
151 u |= 1 << KPF_BUDDY;
152 else if (page_count(page) == 0 && is_free_buddy_page(page))
153 u |= 1 << KPF_BUDDY;
154
155 if (PageBalloon(page))
156 u |= 1 << KPF_BALLOON;
157
158 if (page_is_idle(page))
159 u |= 1 << KPF_IDLE;
160
161 u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
162
163 u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
164 if (PageTail(page) && PageSlab(compound_head(page)))
165 u |= 1 << KPF_SLAB;
166
167 u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
168 u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
169 u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
170 u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
171
172 u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
173 u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
174 u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
175 u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
176
177 if (PageSwapCache(page))
178 u |= 1 << KPF_SWAPCACHE;
179 u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
180
181 u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
182 u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked);
183
184#ifdef CONFIG_MEMORY_FAILURE
185 u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison);
186#endif
187
188#ifdef CONFIG_ARCH_USES_PG_UNCACHED
189 u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached);
190#endif
191
192 u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
193 u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
194 u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
195 u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
196 u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
197 u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
198
199 return u;
200};
201
202static ssize_t kpageflags_read(struct file *file, char __user *buf,
203 size_t count, loff_t *ppos)
204{
205 u64 __user *out = (u64 __user *)buf;
206 struct page *ppage;
207 unsigned long src = *ppos;
208 unsigned long pfn;
209 ssize_t ret = 0;
210
211 pfn = src / KPMSIZE;
212 count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
213 if (src & KPMMASK || count & KPMMASK)
214 return -EINVAL;
215
216 while (count > 0) {
217 if (pfn_valid(pfn))
218 ppage = pfn_to_page(pfn);
219 else
220 ppage = NULL;
221
222 if (put_user(stable_page_flags(ppage), out)) {
223 ret = -EFAULT;
224 break;
225 }
226
227 pfn++;
228 out++;
229 count -= KPMSIZE;
230
231 cond_resched();
232 }
233
234 *ppos += (char __user *)out - buf;
235 if (!ret)
236 ret = (char __user *)out - buf;
237 return ret;
238}
239
240static const struct file_operations proc_kpageflags_operations = {
241 .llseek = mem_lseek,
242 .read = kpageflags_read,
243};
244
245#ifdef CONFIG_MEMCG
246static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
247 size_t count, loff_t *ppos)
248{
249 u64 __user *out = (u64 __user *)buf;
250 struct page *ppage;
251 unsigned long src = *ppos;
252 unsigned long pfn;
253 ssize_t ret = 0;
254 u64 ino;
255
256 pfn = src / KPMSIZE;
257 count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
258 if (src & KPMMASK || count & KPMMASK)
259 return -EINVAL;
260
261 while (count > 0) {
262 if (pfn_valid(pfn))
263 ppage = pfn_to_page(pfn);
264 else
265 ppage = NULL;
266
267 if (ppage)
268 ino = page_cgroup_ino(ppage);
269 else
270 ino = 0;
271
272 if (put_user(ino, out)) {
273 ret = -EFAULT;
274 break;
275 }
276
277 pfn++;
278 out++;
279 count -= KPMSIZE;
280
281 cond_resched();
282 }
283
284 *ppos += (char __user *)out - buf;
285 if (!ret)
286 ret = (char __user *)out - buf;
287 return ret;
288}
289
290static const struct file_operations proc_kpagecgroup_operations = {
291 .llseek = mem_lseek,
292 .read = kpagecgroup_read,
293};
294#endif /* CONFIG_MEMCG */
295
296static int __init proc_page_init(void)
297{
298 proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
299 proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
300#ifdef CONFIG_MEMCG
301 proc_create("kpagecgroup", S_IRUSR, NULL, &proc_kpagecgroup_operations);
302#endif
303 return 0;
304}
305fs_initcall(proc_page_init);