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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 else if (PageTransCompound(page))
119 u |= 1 << KPF_THP;
120
121 /*
122 * Caveats on high order pages: page->_count will only be set
123 * -1 on the head page; SLUB/SLQB do the same for PG_slab;
124 * SLOB won't set PG_slab at all on compound pages.
125 */
126 if (PageBuddy(page))
127 u |= 1 << KPF_BUDDY;
128
129 u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
130
131 u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
132
133 u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
134 u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
135 u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
136 u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
137
138 u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
139 u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
140 u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
141 u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
142
143 u |= kpf_copy_bit(k, KPF_SWAPCACHE, PG_swapcache);
144 u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
145
146 u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
147 u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked);
148
149#ifdef CONFIG_MEMORY_FAILURE
150 u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison);
151#endif
152
153#ifdef CONFIG_ARCH_USES_PG_UNCACHED
154 u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached);
155#endif
156
157 u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
158 u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
159 u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
160 u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
161 u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
162 u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
163
164 return u;
165};
166
167static ssize_t kpageflags_read(struct file *file, char __user *buf,
168 size_t count, loff_t *ppos)
169{
170 u64 __user *out = (u64 __user *)buf;
171 struct page *ppage;
172 unsigned long src = *ppos;
173 unsigned long pfn;
174 ssize_t ret = 0;
175
176 pfn = src / KPMSIZE;
177 count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
178 if (src & KPMMASK || count & KPMMASK)
179 return -EINVAL;
180
181 while (count > 0) {
182 if (pfn_valid(pfn))
183 ppage = pfn_to_page(pfn);
184 else
185 ppage = NULL;
186
187 if (put_user(stable_page_flags(ppage), out)) {
188 ret = -EFAULT;
189 break;
190 }
191
192 pfn++;
193 out++;
194 count -= KPMSIZE;
195 }
196
197 *ppos += (char __user *)out - buf;
198 if (!ret)
199 ret = (char __user *)out - buf;
200 return ret;
201}
202
203static const struct file_operations proc_kpageflags_operations = {
204 .llseek = mem_lseek,
205 .read = kpageflags_read,
206};
207
208static int __init proc_page_init(void)
209{
210 proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
211 proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
212 return 0;
213}
214module_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 SLAB, 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: PG_buddy and PG_slab will only be set
169 * on the head page.
170 */
171 if (PageBuddy(page))
172 u |= 1 << KPF_BUDDY;
173 else if (page_count(page) == 0 && is_free_buddy_page(page))
174 u |= 1 << KPF_BUDDY;
175
176 if (PageOffline(page))
177 u |= 1 << KPF_OFFLINE;
178 if (PageTable(page))
179 u |= 1 << KPF_PGTABLE;
180
181 if (page_is_idle(page))
182 u |= 1 << KPF_IDLE;
183
184 u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
185
186 u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
187 if (PageTail(page) && PageSlab(page))
188 u |= 1 << KPF_SLAB;
189
190 u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
191 u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
192 u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
193 u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
194
195 u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
196 u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
197 u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
198 u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
199
200 if (PageSwapCache(page))
201 u |= 1 << KPF_SWAPCACHE;
202 u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
203
204 u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
205 u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked);
206
207#ifdef CONFIG_MEMORY_FAILURE
208 u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison);
209#endif
210
211#ifdef CONFIG_ARCH_USES_PG_UNCACHED
212 u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached);
213#endif
214
215 u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
216 u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
217 u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
218 u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
219 u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
220 u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
221#ifdef CONFIG_ARCH_USES_PG_ARCH_X
222 u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2);
223 u |= kpf_copy_bit(k, KPF_ARCH_3, PG_arch_3);
224#endif
225
226 return u;
227};
228
229static ssize_t kpageflags_read(struct file *file, char __user *buf,
230 size_t count, loff_t *ppos)
231{
232 const unsigned long max_dump_pfn = get_max_dump_pfn();
233 u64 __user *out = (u64 __user *)buf;
234 struct page *ppage;
235 unsigned long src = *ppos;
236 unsigned long pfn;
237 ssize_t ret = 0;
238
239 pfn = src / KPMSIZE;
240 if (src & KPMMASK || count & KPMMASK)
241 return -EINVAL;
242 if (src >= max_dump_pfn * KPMSIZE)
243 return 0;
244 count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
245
246 while (count > 0) {
247 /*
248 * TODO: ZONE_DEVICE support requires to identify
249 * memmaps that were actually initialized.
250 */
251 ppage = pfn_to_online_page(pfn);
252
253 if (put_user(stable_page_flags(ppage), out)) {
254 ret = -EFAULT;
255 break;
256 }
257
258 pfn++;
259 out++;
260 count -= KPMSIZE;
261
262 cond_resched();
263 }
264
265 *ppos += (char __user *)out - buf;
266 if (!ret)
267 ret = (char __user *)out - buf;
268 return ret;
269}
270
271static const struct proc_ops kpageflags_proc_ops = {
272 .proc_flags = PROC_ENTRY_PERMANENT,
273 .proc_lseek = mem_lseek,
274 .proc_read = kpageflags_read,
275};
276
277#ifdef CONFIG_MEMCG
278static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
279 size_t count, loff_t *ppos)
280{
281 const unsigned long max_dump_pfn = get_max_dump_pfn();
282 u64 __user *out = (u64 __user *)buf;
283 struct page *ppage;
284 unsigned long src = *ppos;
285 unsigned long pfn;
286 ssize_t ret = 0;
287 u64 ino;
288
289 pfn = src / KPMSIZE;
290 if (src & KPMMASK || count & KPMMASK)
291 return -EINVAL;
292 if (src >= max_dump_pfn * KPMSIZE)
293 return 0;
294 count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
295
296 while (count > 0) {
297 /*
298 * TODO: ZONE_DEVICE support requires to identify
299 * memmaps that were actually initialized.
300 */
301 ppage = pfn_to_online_page(pfn);
302
303 if (ppage)
304 ino = page_cgroup_ino(ppage);
305 else
306 ino = 0;
307
308 if (put_user(ino, out)) {
309 ret = -EFAULT;
310 break;
311 }
312
313 pfn++;
314 out++;
315 count -= KPMSIZE;
316
317 cond_resched();
318 }
319
320 *ppos += (char __user *)out - buf;
321 if (!ret)
322 ret = (char __user *)out - buf;
323 return ret;
324}
325
326static const struct proc_ops kpagecgroup_proc_ops = {
327 .proc_flags = PROC_ENTRY_PERMANENT,
328 .proc_lseek = mem_lseek,
329 .proc_read = kpagecgroup_read,
330};
331#endif /* CONFIG_MEMCG */
332
333static int __init proc_page_init(void)
334{
335 proc_create("kpagecount", S_IRUSR, NULL, &kpagecount_proc_ops);
336 proc_create("kpageflags", S_IRUSR, NULL, &kpageflags_proc_ops);
337#ifdef CONFIG_MEMCG
338 proc_create("kpagecgroup", S_IRUSR, NULL, &kpagecgroup_proc_ops);
339#endif
340 return 0;
341}
342fs_initcall(proc_page_init);