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c9465b4e LA |
1 | /* |
2 | * Copyright (c) 2014, The Linux Foundation. All rights reserved. | |
3 | * Debug helper to dump the current kernel pagetables of the system | |
4 | * so that we can see what the various memory ranges are set to. | |
5 | * | |
6 | * Derived from x86 and arm implementation: | |
7 | * (C) Copyright 2008 Intel Corporation | |
8 | * | |
9 | * Author: Arjan van de Ven <arjan@linux.intel.com> | |
10 | * | |
11 | * This program is free software; you can redistribute it and/or | |
12 | * modify it under the terms of the GNU General Public License | |
13 | * as published by the Free Software Foundation; version 2 | |
14 | * of the License. | |
15 | */ | |
16 | #include <linux/debugfs.h> | |
764011ca | 17 | #include <linux/errno.h> |
c9465b4e | 18 | #include <linux/fs.h> |
284be285 | 19 | #include <linux/io.h> |
764011ca | 20 | #include <linux/init.h> |
c9465b4e LA |
21 | #include <linux/mm.h> |
22 | #include <linux/sched.h> | |
23 | #include <linux/seq_file.h> | |
24 | ||
25 | #include <asm/fixmap.h> | |
d8fc68a0 | 26 | #include <asm/kasan.h> |
764011ca | 27 | #include <asm/memory.h> |
c9465b4e | 28 | #include <asm/pgtable.h> |
764011ca | 29 | #include <asm/pgtable-hwdef.h> |
4674fdb9 | 30 | #include <asm/ptdump.h> |
c9465b4e | 31 | |
c8f8cca4 | 32 | static const struct addr_marker address_markers[] = { |
d8fc68a0 AB |
33 | #ifdef CONFIG_KASAN |
34 | { KASAN_SHADOW_START, "Kasan shadow start" }, | |
35 | { KASAN_SHADOW_END, "Kasan shadow end" }, | |
36 | #endif | |
c8f8cca4 AB |
37 | { MODULES_VADDR, "Modules start" }, |
38 | { MODULES_END, "Modules end" }, | |
39 | { VMALLOC_START, "vmalloc() Area" }, | |
40 | { VMALLOC_END, "vmalloc() End" }, | |
41 | { FIXADDR_START, "Fixmap start" }, | |
42 | { FIXADDR_TOP, "Fixmap end" }, | |
43 | { PCI_IO_START, "PCI I/O start" }, | |
44 | { PCI_IO_END, "PCI I/O end" }, | |
3e1907d5 | 45 | #ifdef CONFIG_SPARSEMEM_VMEMMAP |
c8f8cca4 AB |
46 | { VMEMMAP_START, "vmemmap start" }, |
47 | { VMEMMAP_START + VMEMMAP_SIZE, "vmemmap end" }, | |
3e1907d5 | 48 | #endif |
c8f8cca4 AB |
49 | { PAGE_OFFSET, "Linear Mapping" }, |
50 | { -1, NULL }, | |
c9465b4e LA |
51 | }; |
52 | ||
ae5d1cf3 LA |
53 | #define pt_dump_seq_printf(m, fmt, args...) \ |
54 | ({ \ | |
55 | if (m) \ | |
56 | seq_printf(m, fmt, ##args); \ | |
57 | }) | |
58 | ||
59 | #define pt_dump_seq_puts(m, fmt) \ | |
60 | ({ \ | |
61 | if (m) \ | |
62 | seq_printf(m, fmt); \ | |
63 | }) | |
64 | ||
202e41a1 JL |
65 | /* |
66 | * The page dumper groups page table entries of the same type into a single | |
67 | * description. It uses pg_state to track the range information while | |
68 | * iterating over the pte entries. When the continuity is broken it then | |
69 | * dumps out a description of the range. | |
70 | */ | |
c9465b4e LA |
71 | struct pg_state { |
72 | struct seq_file *seq; | |
73 | const struct addr_marker *marker; | |
74 | unsigned long start_address; | |
75 | unsigned level; | |
76 | u64 current_prot; | |
1404d6f1 LA |
77 | bool check_wx; |
78 | unsigned long wx_pages; | |
79 | unsigned long uxn_pages; | |
c9465b4e LA |
80 | }; |
81 | ||
82 | struct prot_bits { | |
83 | u64 mask; | |
84 | u64 val; | |
85 | const char *set; | |
86 | const char *clear; | |
87 | }; | |
88 | ||
89 | static const struct prot_bits pte_bits[] = { | |
90 | { | |
d7e9d594 LA |
91 | .mask = PTE_VALID, |
92 | .val = PTE_VALID, | |
93 | .set = " ", | |
94 | .clear = "F", | |
95 | }, { | |
c9465b4e LA |
96 | .mask = PTE_USER, |
97 | .val = PTE_USER, | |
98 | .set = "USR", | |
99 | .clear = " ", | |
100 | }, { | |
101 | .mask = PTE_RDONLY, | |
102 | .val = PTE_RDONLY, | |
103 | .set = "ro", | |
104 | .clear = "RW", | |
105 | }, { | |
106 | .mask = PTE_PXN, | |
107 | .val = PTE_PXN, | |
108 | .set = "NX", | |
109 | .clear = "x ", | |
110 | }, { | |
111 | .mask = PTE_SHARED, | |
112 | .val = PTE_SHARED, | |
113 | .set = "SHD", | |
114 | .clear = " ", | |
115 | }, { | |
116 | .mask = PTE_AF, | |
117 | .val = PTE_AF, | |
118 | .set = "AF", | |
119 | .clear = " ", | |
120 | }, { | |
121 | .mask = PTE_NG, | |
122 | .val = PTE_NG, | |
123 | .set = "NG", | |
124 | .clear = " ", | |
202e41a1 JL |
125 | }, { |
126 | .mask = PTE_CONT, | |
127 | .val = PTE_CONT, | |
128 | .set = "CON", | |
129 | .clear = " ", | |
130 | }, { | |
131 | .mask = PTE_TABLE_BIT, | |
132 | .val = PTE_TABLE_BIT, | |
133 | .set = " ", | |
134 | .clear = "BLK", | |
c9465b4e LA |
135 | }, { |
136 | .mask = PTE_UXN, | |
137 | .val = PTE_UXN, | |
138 | .set = "UXN", | |
139 | }, { | |
140 | .mask = PTE_ATTRINDX_MASK, | |
141 | .val = PTE_ATTRINDX(MT_DEVICE_nGnRnE), | |
142 | .set = "DEVICE/nGnRnE", | |
143 | }, { | |
144 | .mask = PTE_ATTRINDX_MASK, | |
145 | .val = PTE_ATTRINDX(MT_DEVICE_nGnRE), | |
146 | .set = "DEVICE/nGnRE", | |
147 | }, { | |
148 | .mask = PTE_ATTRINDX_MASK, | |
149 | .val = PTE_ATTRINDX(MT_DEVICE_GRE), | |
150 | .set = "DEVICE/GRE", | |
151 | }, { | |
152 | .mask = PTE_ATTRINDX_MASK, | |
153 | .val = PTE_ATTRINDX(MT_NORMAL_NC), | |
154 | .set = "MEM/NORMAL-NC", | |
155 | }, { | |
156 | .mask = PTE_ATTRINDX_MASK, | |
157 | .val = PTE_ATTRINDX(MT_NORMAL), | |
158 | .set = "MEM/NORMAL", | |
159 | } | |
160 | }; | |
161 | ||
162 | struct pg_level { | |
163 | const struct prot_bits *bits; | |
48dd73c5 | 164 | const char *name; |
c9465b4e LA |
165 | size_t num; |
166 | u64 mask; | |
167 | }; | |
168 | ||
169 | static struct pg_level pg_level[] = { | |
170 | { | |
171 | }, { /* pgd */ | |
48dd73c5 | 172 | .name = "PGD", |
c9465b4e LA |
173 | .bits = pte_bits, |
174 | .num = ARRAY_SIZE(pte_bits), | |
175 | }, { /* pud */ | |
48dd73c5 | 176 | .name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD", |
c9465b4e LA |
177 | .bits = pte_bits, |
178 | .num = ARRAY_SIZE(pte_bits), | |
179 | }, { /* pmd */ | |
48dd73c5 | 180 | .name = (CONFIG_PGTABLE_LEVELS > 2) ? "PMD" : "PGD", |
c9465b4e LA |
181 | .bits = pte_bits, |
182 | .num = ARRAY_SIZE(pte_bits), | |
183 | }, { /* pte */ | |
48dd73c5 | 184 | .name = "PTE", |
c9465b4e LA |
185 | .bits = pte_bits, |
186 | .num = ARRAY_SIZE(pte_bits), | |
187 | }, | |
188 | }; | |
189 | ||
190 | static void dump_prot(struct pg_state *st, const struct prot_bits *bits, | |
191 | size_t num) | |
192 | { | |
193 | unsigned i; | |
194 | ||
195 | for (i = 0; i < num; i++, bits++) { | |
196 | const char *s; | |
197 | ||
198 | if ((st->current_prot & bits->mask) == bits->val) | |
199 | s = bits->set; | |
200 | else | |
201 | s = bits->clear; | |
202 | ||
203 | if (s) | |
ae5d1cf3 | 204 | pt_dump_seq_printf(st->seq, " %s", s); |
c9465b4e LA |
205 | } |
206 | } | |
207 | ||
1404d6f1 LA |
208 | static void note_prot_uxn(struct pg_state *st, unsigned long addr) |
209 | { | |
210 | if (!st->check_wx) | |
211 | return; | |
212 | ||
213 | if ((st->current_prot & PTE_UXN) == PTE_UXN) | |
214 | return; | |
215 | ||
216 | WARN_ONCE(1, "arm64/mm: Found non-UXN mapping at address %p/%pS\n", | |
217 | (void *)st->start_address, (void *)st->start_address); | |
218 | ||
219 | st->uxn_pages += (addr - st->start_address) / PAGE_SIZE; | |
220 | } | |
221 | ||
222 | static void note_prot_wx(struct pg_state *st, unsigned long addr) | |
223 | { | |
224 | if (!st->check_wx) | |
225 | return; | |
226 | if ((st->current_prot & PTE_RDONLY) == PTE_RDONLY) | |
227 | return; | |
228 | if ((st->current_prot & PTE_PXN) == PTE_PXN) | |
229 | return; | |
230 | ||
231 | WARN_ONCE(1, "arm64/mm: Found insecure W+X mapping at address %p/%pS\n", | |
232 | (void *)st->start_address, (void *)st->start_address); | |
233 | ||
234 | st->wx_pages += (addr - st->start_address) / PAGE_SIZE; | |
235 | } | |
236 | ||
c9465b4e LA |
237 | static void note_page(struct pg_state *st, unsigned long addr, unsigned level, |
238 | u64 val) | |
239 | { | |
240 | static const char units[] = "KMGTPE"; | |
241 | u64 prot = val & pg_level[level].mask; | |
242 | ||
c9465b4e LA |
243 | if (!st->level) { |
244 | st->level = level; | |
245 | st->current_prot = prot; | |
246 | st->start_address = addr; | |
ae5d1cf3 | 247 | pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); |
c9465b4e LA |
248 | } else if (prot != st->current_prot || level != st->level || |
249 | addr >= st->marker[1].start_address) { | |
250 | const char *unit = units; | |
251 | unsigned long delta; | |
252 | ||
253 | if (st->current_prot) { | |
1404d6f1 LA |
254 | note_prot_uxn(st, addr); |
255 | note_prot_wx(st, addr); | |
ae5d1cf3 | 256 | pt_dump_seq_printf(st->seq, "0x%016lx-0x%016lx ", |
c9465b4e LA |
257 | st->start_address, addr); |
258 | ||
259 | delta = (addr - st->start_address) >> 10; | |
260 | while (!(delta & 1023) && unit[1]) { | |
261 | delta >>= 10; | |
262 | unit++; | |
263 | } | |
ae5d1cf3 | 264 | pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit, |
48dd73c5 | 265 | pg_level[st->level].name); |
c9465b4e LA |
266 | if (pg_level[st->level].bits) |
267 | dump_prot(st, pg_level[st->level].bits, | |
268 | pg_level[st->level].num); | |
ae5d1cf3 | 269 | pt_dump_seq_puts(st->seq, "\n"); |
c9465b4e LA |
270 | } |
271 | ||
272 | if (addr >= st->marker[1].start_address) { | |
273 | st->marker++; | |
ae5d1cf3 | 274 | pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); |
c9465b4e LA |
275 | } |
276 | ||
277 | st->start_address = addr; | |
278 | st->current_prot = prot; | |
279 | st->level = level; | |
280 | } | |
281 | ||
282 | if (addr >= st->marker[1].start_address) { | |
283 | st->marker++; | |
ae5d1cf3 | 284 | pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); |
c9465b4e LA |
285 | } |
286 | ||
287 | } | |
288 | ||
289 | static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start) | |
290 | { | |
a93a4d62 | 291 | pte_t *pte = pte_offset_kernel(pmd, 0UL); |
c9465b4e LA |
292 | unsigned long addr; |
293 | unsigned i; | |
294 | ||
295 | for (i = 0; i < PTRS_PER_PTE; i++, pte++) { | |
296 | addr = start + i * PAGE_SIZE; | |
297 | note_page(st, addr, 4, pte_val(*pte)); | |
298 | } | |
299 | } | |
300 | ||
301 | static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start) | |
302 | { | |
a93a4d62 | 303 | pmd_t *pmd = pmd_offset(pud, 0UL); |
c9465b4e LA |
304 | unsigned long addr; |
305 | unsigned i; | |
306 | ||
307 | for (i = 0; i < PTRS_PER_PMD; i++, pmd++) { | |
308 | addr = start + i * PMD_SIZE; | |
a1c76574 | 309 | if (pmd_none(*pmd) || pmd_sect(*pmd)) { |
c9465b4e | 310 | note_page(st, addr, 3, pmd_val(*pmd)); |
a1c76574 MR |
311 | } else { |
312 | BUG_ON(pmd_bad(*pmd)); | |
c9465b4e | 313 | walk_pte(st, pmd, addr); |
a1c76574 | 314 | } |
c9465b4e LA |
315 | } |
316 | } | |
317 | ||
318 | static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start) | |
319 | { | |
a93a4d62 | 320 | pud_t *pud = pud_offset(pgd, 0UL); |
c9465b4e LA |
321 | unsigned long addr; |
322 | unsigned i; | |
323 | ||
324 | for (i = 0; i < PTRS_PER_PUD; i++, pud++) { | |
325 | addr = start + i * PUD_SIZE; | |
a1c76574 | 326 | if (pud_none(*pud) || pud_sect(*pud)) { |
c9465b4e | 327 | note_page(st, addr, 2, pud_val(*pud)); |
a1c76574 MR |
328 | } else { |
329 | BUG_ON(pud_bad(*pud)); | |
c9465b4e | 330 | walk_pmd(st, pud, addr); |
a1c76574 | 331 | } |
c9465b4e LA |
332 | } |
333 | } | |
334 | ||
4674fdb9 MR |
335 | static void walk_pgd(struct pg_state *st, struct mm_struct *mm, |
336 | unsigned long start) | |
c9465b4e | 337 | { |
35545f0c | 338 | pgd_t *pgd = pgd_offset(mm, 0UL); |
c9465b4e LA |
339 | unsigned i; |
340 | unsigned long addr; | |
341 | ||
342 | for (i = 0; i < PTRS_PER_PGD; i++, pgd++) { | |
343 | addr = start + i * PGDIR_SIZE; | |
a1c76574 | 344 | if (pgd_none(*pgd)) { |
c9465b4e | 345 | note_page(st, addr, 1, pgd_val(*pgd)); |
a1c76574 MR |
346 | } else { |
347 | BUG_ON(pgd_bad(*pgd)); | |
c9465b4e | 348 | walk_pud(st, pgd, addr); |
a1c76574 | 349 | } |
c9465b4e LA |
350 | } |
351 | } | |
352 | ||
4ddb9bf8 | 353 | void ptdump_walk_pgd(struct seq_file *m, struct ptdump_info *info) |
c9465b4e LA |
354 | { |
355 | struct pg_state st = { | |
356 | .seq = m, | |
4674fdb9 | 357 | .marker = info->markers, |
c9465b4e LA |
358 | }; |
359 | ||
4674fdb9 | 360 | walk_pgd(&st, info->mm, info->base_addr); |
c9465b4e LA |
361 | |
362 | note_page(&st, 0, 0, 0); | |
c9465b4e LA |
363 | } |
364 | ||
4ddb9bf8 | 365 | static void ptdump_initialize(void) |
c9465b4e | 366 | { |
c9465b4e LA |
367 | unsigned i, j; |
368 | ||
369 | for (i = 0; i < ARRAY_SIZE(pg_level); i++) | |
370 | if (pg_level[i].bits) | |
371 | for (j = 0; j < pg_level[i].num; j++) | |
372 | pg_level[i].mask |= pg_level[i].bits[j].mask; | |
c9465b4e | 373 | } |
4674fdb9 MR |
374 | |
375 | static struct ptdump_info kernel_ptdump_info = { | |
376 | .mm = &init_mm, | |
377 | .markers = address_markers, | |
378 | .base_addr = VA_START, | |
379 | }; | |
380 | ||
1404d6f1 LA |
381 | void ptdump_check_wx(void) |
382 | { | |
383 | struct pg_state st = { | |
384 | .seq = NULL, | |
385 | .marker = (struct addr_marker[]) { | |
386 | { 0, NULL}, | |
387 | { -1, NULL}, | |
388 | }, | |
389 | .check_wx = true, | |
390 | }; | |
391 | ||
392 | walk_pgd(&st, &init_mm, 0); | |
393 | note_page(&st, 0, 0, 0); | |
394 | if (st.wx_pages || st.uxn_pages) | |
395 | pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found, %lu non-UXN pages found\n", | |
396 | st.wx_pages, st.uxn_pages); | |
397 | else | |
398 | pr_info("Checked W+X mappings: passed, no W+X pages found\n"); | |
399 | } | |
400 | ||
4674fdb9 MR |
401 | static int ptdump_init(void) |
402 | { | |
4ddb9bf8 LA |
403 | ptdump_initialize(); |
404 | return ptdump_debugfs_register(&kernel_ptdump_info, | |
405 | "kernel_page_tables"); | |
4674fdb9 | 406 | } |
c9465b4e | 407 | device_initcall(ptdump_init); |