Line data Source code
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 :
25 : static 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 0 : 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 : */
45 0 : static ssize_t kpagecount_read(struct file *file, char __user *buf,
46 : size_t count, loff_t *ppos)
47 : {
48 0 : const unsigned long max_dump_pfn = get_max_dump_pfn();
49 0 : u64 __user *out = (u64 __user *)buf;
50 : struct page *ppage;
51 0 : unsigned long src = *ppos;
52 : unsigned long pfn;
53 0 : ssize_t ret = 0;
54 : u64 pcount;
55 :
56 0 : pfn = src / KPMSIZE;
57 0 : if (src & KPMMASK || count & KPMMASK)
58 : return -EINVAL;
59 0 : if (src >= max_dump_pfn * KPMSIZE)
60 : return 0;
61 0 : count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
62 :
63 0 : while (count > 0) {
64 : /*
65 : * TODO: ZONE_DEVICE support requires to identify
66 : * memmaps that were actually initialized.
67 : */
68 0 : ppage = pfn_to_online_page(pfn);
69 :
70 0 : if (!ppage || PageSlab(ppage) || page_has_type(ppage))
71 : pcount = 0;
72 : else
73 0 : pcount = page_mapcount(ppage);
74 :
75 0 : if (put_user(pcount, out)) {
76 : ret = -EFAULT;
77 : break;
78 : }
79 :
80 0 : pfn++;
81 0 : out++;
82 0 : count -= KPMSIZE;
83 :
84 0 : cond_resched();
85 : }
86 :
87 0 : *ppos += (char __user *)out - buf;
88 0 : if (!ret)
89 0 : ret = (char __user *)out - buf;
90 : return ret;
91 : }
92 :
93 : static 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 :
105 : static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
106 : {
107 0 : return ((kflags >> kbit) & 1) << ubit;
108 : }
109 :
110 0 : u64 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 0 : if (!page)
120 : return 1 << KPF_NOPAGE;
121 :
122 0 : k = page->flags;
123 0 : 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 0 : if (!PageSlab(page) && page_mapped(page))
132 0 : u |= 1 << KPF_MMAP;
133 0 : if (PageAnon(page))
134 0 : u |= 1 << KPF_ANON;
135 0 : 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 0 : if (PageHead(page))
143 0 : u |= 1 << KPF_COMPOUND_HEAD;
144 0 : if (PageTail(page))
145 0 : u |= 1 << KPF_COMPOUND_TAIL;
146 0 : 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 0 : 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 0 : } else if (is_zero_pfn(page_to_pfn(page)))
164 0 : 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 0 : if (PageBuddy(page))
172 0 : u |= 1 << KPF_BUDDY;
173 0 : else if (page_count(page) == 0 && is_free_buddy_page(page))
174 0 : u |= 1 << KPF_BUDDY;
175 :
176 0 : if (PageOffline(page))
177 0 : u |= 1 << KPF_OFFLINE;
178 0 : if (PageTable(page))
179 0 : u |= 1 << KPF_PGTABLE;
180 :
181 0 : if (page_is_idle(page))
182 : u |= 1 << KPF_IDLE;
183 :
184 0 : u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
185 :
186 0 : u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
187 0 : if (PageTail(page) && PageSlab(page))
188 0 : u |= 1 << KPF_SLAB;
189 :
190 0 : u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
191 0 : u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
192 0 : u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
193 0 : u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
194 :
195 0 : u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
196 0 : u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
197 0 : u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
198 0 : u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
199 :
200 0 : if (PageSwapCache(page))
201 0 : u |= 1 << KPF_SWAPCACHE;
202 0 : u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
203 :
204 0 : u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
205 0 : 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 0 : u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
216 0 : u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
217 0 : u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
218 0 : u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
219 0 : u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
220 0 : 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 0 : return u;
227 : };
228 :
229 0 : static ssize_t kpageflags_read(struct file *file, char __user *buf,
230 : size_t count, loff_t *ppos)
231 : {
232 0 : const unsigned long max_dump_pfn = get_max_dump_pfn();
233 0 : u64 __user *out = (u64 __user *)buf;
234 : struct page *ppage;
235 0 : unsigned long src = *ppos;
236 : unsigned long pfn;
237 0 : ssize_t ret = 0;
238 :
239 0 : pfn = src / KPMSIZE;
240 0 : if (src & KPMMASK || count & KPMMASK)
241 : return -EINVAL;
242 0 : if (src >= max_dump_pfn * KPMSIZE)
243 : return 0;
244 0 : count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
245 :
246 0 : while (count > 0) {
247 : /*
248 : * TODO: ZONE_DEVICE support requires to identify
249 : * memmaps that were actually initialized.
250 : */
251 0 : ppage = pfn_to_online_page(pfn);
252 :
253 0 : if (put_user(stable_page_flags(ppage), out)) {
254 : ret = -EFAULT;
255 : break;
256 : }
257 :
258 0 : pfn++;
259 0 : out++;
260 0 : count -= KPMSIZE;
261 :
262 0 : cond_resched();
263 : }
264 :
265 0 : *ppos += (char __user *)out - buf;
266 0 : if (!ret)
267 0 : ret = (char __user *)out - buf;
268 : return ret;
269 : }
270 :
271 : static 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
278 : static 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 :
326 : static 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 :
333 1 : static int __init proc_page_init(void)
334 : {
335 1 : proc_create("kpagecount", S_IRUSR, NULL, &kpagecount_proc_ops);
336 1 : 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 1 : return 0;
341 : }
342 : fs_initcall(proc_page_init);
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