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 SLOB/SLUB/SLQB, 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: 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 0 : if (PageBuddy(page))
173 0 : u |= 1 << KPF_BUDDY;
174 0 : else if (page_count(page) == 0 && is_free_buddy_page(page))
175 0 : u |= 1 << KPF_BUDDY;
176 :
177 0 : if (PageOffline(page))
178 0 : u |= 1 << KPF_OFFLINE;
179 0 : if (PageTable(page))
180 0 : u |= 1 << KPF_PGTABLE;
181 :
182 0 : if (page_is_idle(page))
183 : u |= 1 << KPF_IDLE;
184 :
185 0 : u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
186 :
187 0 : u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
188 0 : if (PageTail(page) && PageSlab(compound_head(page)))
189 0 : u |= 1 << KPF_SLAB;
190 :
191 0 : u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
192 0 : u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
193 0 : u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
194 0 : u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
195 :
196 0 : u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
197 0 : u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
198 0 : u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
199 0 : u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
200 :
201 0 : if (PageSwapCache(page))
202 0 : u |= 1 << KPF_SWAPCACHE;
203 0 : u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
204 :
205 0 : u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
206 0 : 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 0 : u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
217 0 : u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
218 0 : u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
219 0 : u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
220 0 : u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
221 0 : 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 0 : return u;
228 : };
229 :
230 0 : static ssize_t kpageflags_read(struct file *file, char __user *buf,
231 : size_t count, loff_t *ppos)
232 : {
233 0 : const unsigned long max_dump_pfn = get_max_dump_pfn();
234 0 : u64 __user *out = (u64 __user *)buf;
235 : struct page *ppage;
236 0 : unsigned long src = *ppos;
237 : unsigned long pfn;
238 0 : ssize_t ret = 0;
239 :
240 0 : pfn = src / KPMSIZE;
241 0 : if (src & KPMMASK || count & KPMMASK)
242 : return -EINVAL;
243 0 : if (src >= max_dump_pfn * KPMSIZE)
244 : return 0;
245 0 : count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
246 :
247 0 : while (count > 0) {
248 : /*
249 : * TODO: ZONE_DEVICE support requires to identify
250 : * memmaps that were actually initialized.
251 : */
252 0 : ppage = pfn_to_online_page(pfn);
253 :
254 0 : if (put_user(stable_page_flags(ppage), out)) {
255 : ret = -EFAULT;
256 : break;
257 : }
258 :
259 0 : pfn++;
260 0 : out++;
261 0 : count -= KPMSIZE;
262 :
263 0 : cond_resched();
264 : }
265 :
266 0 : *ppos += (char __user *)out - buf;
267 0 : if (!ret)
268 0 : ret = (char __user *)out - buf;
269 : return ret;
270 : }
271 :
272 : static 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
279 : static 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 :
327 : static 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 :
334 1 : static int __init proc_page_init(void)
335 : {
336 1 : proc_create("kpagecount", S_IRUSR, NULL, &kpagecount_proc_ops);
337 1 : 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 1 : return 0;
342 : }
343 : fs_initcall(proc_page_init);
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