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e886bf9d | 1 | // SPDX-License-Identifier: GPL-2.0 |
69786cdb AR |
2 | /* |
3 | * This file contains some kasan initialization code. | |
4 | * | |
5 | * Copyright (c) 2015 Samsung Electronics Co., Ltd. | |
6 | * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
12 | */ | |
13 | ||
57c8a661 | 14 | #include <linux/memblock.h> |
69786cdb AR |
15 | #include <linux/init.h> |
16 | #include <linux/kasan.h> | |
17 | #include <linux/kernel.h> | |
5c6a84a3 | 18 | #include <linux/mm.h> |
69786cdb | 19 | #include <linux/pfn.h> |
0207df4f | 20 | #include <linux/slab.h> |
69786cdb AR |
21 | |
22 | #include <asm/page.h> | |
23 | #include <asm/pgalloc.h> | |
24 | ||
0207df4f AR |
25 | #include "kasan.h" |
26 | ||
69786cdb AR |
27 | /* |
28 | * This page serves two purposes: | |
29 | * - It used as early shadow memory. The entire shadow region populated | |
30 | * with this page, before we will be able to setup normal shadow memory. | |
31 | * - Latter it reused it as zero shadow to cover large ranges of memory | |
32 | * that allowed to access, but not handled by kasan (vmalloc/vmemmap ...). | |
33 | */ | |
9577dd74 | 34 | unsigned char kasan_early_shadow_page[PAGE_SIZE] __page_aligned_bss; |
69786cdb | 35 | |
c2febafc | 36 | #if CONFIG_PGTABLE_LEVELS > 4 |
9577dd74 | 37 | p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss; |
0207df4f AR |
38 | static inline bool kasan_p4d_table(pgd_t pgd) |
39 | { | |
9577dd74 | 40 | return pgd_page(pgd) == virt_to_page(lm_alias(kasan_early_shadow_p4d)); |
0207df4f AR |
41 | } |
42 | #else | |
43 | static inline bool kasan_p4d_table(pgd_t pgd) | |
44 | { | |
45 | return 0; | |
46 | } | |
c2febafc | 47 | #endif |
69786cdb | 48 | #if CONFIG_PGTABLE_LEVELS > 3 |
9577dd74 | 49 | pud_t kasan_early_shadow_pud[PTRS_PER_PUD] __page_aligned_bss; |
0207df4f AR |
50 | static inline bool kasan_pud_table(p4d_t p4d) |
51 | { | |
9577dd74 | 52 | return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud)); |
0207df4f AR |
53 | } |
54 | #else | |
55 | static inline bool kasan_pud_table(p4d_t p4d) | |
56 | { | |
57 | return 0; | |
58 | } | |
69786cdb AR |
59 | #endif |
60 | #if CONFIG_PGTABLE_LEVELS > 2 | |
9577dd74 | 61 | pmd_t kasan_early_shadow_pmd[PTRS_PER_PMD] __page_aligned_bss; |
0207df4f AR |
62 | static inline bool kasan_pmd_table(pud_t pud) |
63 | { | |
9577dd74 | 64 | return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd)); |
0207df4f AR |
65 | } |
66 | #else | |
67 | static inline bool kasan_pmd_table(pud_t pud) | |
68 | { | |
69 | return 0; | |
70 | } | |
69786cdb | 71 | #endif |
9577dd74 | 72 | pte_t kasan_early_shadow_pte[PTRS_PER_PTE] __page_aligned_bss; |
69786cdb | 73 | |
0207df4f AR |
74 | static inline bool kasan_pte_table(pmd_t pmd) |
75 | { | |
9577dd74 | 76 | return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte)); |
0207df4f AR |
77 | } |
78 | ||
9577dd74 | 79 | static inline bool kasan_early_shadow_page_entry(pte_t pte) |
0207df4f | 80 | { |
9577dd74 | 81 | return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page)); |
0207df4f AR |
82 | } |
83 | ||
69786cdb AR |
84 | static __init void *early_alloc(size_t size, int node) |
85 | { | |
eb31d559 | 86 | return memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS), |
97ad1087 | 87 | MEMBLOCK_ALLOC_ACCESSIBLE, node); |
69786cdb AR |
88 | } |
89 | ||
0207df4f | 90 | static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr, |
69786cdb AR |
91 | unsigned long end) |
92 | { | |
93 | pte_t *pte = pte_offset_kernel(pmd, addr); | |
94 | pte_t zero_pte; | |
95 | ||
9577dd74 AK |
96 | zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)), |
97 | PAGE_KERNEL); | |
69786cdb AR |
98 | zero_pte = pte_wrprotect(zero_pte); |
99 | ||
100 | while (addr + PAGE_SIZE <= end) { | |
101 | set_pte_at(&init_mm, addr, pte, zero_pte); | |
102 | addr += PAGE_SIZE; | |
103 | pte = pte_offset_kernel(pmd, addr); | |
104 | } | |
105 | } | |
106 | ||
0207df4f | 107 | static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr, |
69786cdb AR |
108 | unsigned long end) |
109 | { | |
110 | pmd_t *pmd = pmd_offset(pud, addr); | |
111 | unsigned long next; | |
112 | ||
113 | do { | |
114 | next = pmd_addr_end(addr, end); | |
115 | ||
116 | if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) { | |
9577dd74 AK |
117 | pmd_populate_kernel(&init_mm, pmd, |
118 | lm_alias(kasan_early_shadow_pte)); | |
69786cdb AR |
119 | continue; |
120 | } | |
121 | ||
122 | if (pmd_none(*pmd)) { | |
0207df4f AR |
123 | pte_t *p; |
124 | ||
125 | if (slab_is_available()) | |
4cf58924 | 126 | p = pte_alloc_one_kernel(&init_mm); |
0207df4f AR |
127 | else |
128 | p = early_alloc(PAGE_SIZE, NUMA_NO_NODE); | |
129 | if (!p) | |
130 | return -ENOMEM; | |
131 | ||
132 | pmd_populate_kernel(&init_mm, pmd, p); | |
69786cdb AR |
133 | } |
134 | zero_pte_populate(pmd, addr, next); | |
135 | } while (pmd++, addr = next, addr != end); | |
0207df4f AR |
136 | |
137 | return 0; | |
69786cdb AR |
138 | } |
139 | ||
0207df4f | 140 | static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr, |
69786cdb AR |
141 | unsigned long end) |
142 | { | |
c2febafc | 143 | pud_t *pud = pud_offset(p4d, addr); |
69786cdb AR |
144 | unsigned long next; |
145 | ||
146 | do { | |
147 | next = pud_addr_end(addr, end); | |
148 | if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) { | |
149 | pmd_t *pmd; | |
150 | ||
9577dd74 AK |
151 | pud_populate(&init_mm, pud, |
152 | lm_alias(kasan_early_shadow_pmd)); | |
69786cdb | 153 | pmd = pmd_offset(pud, addr); |
9577dd74 AK |
154 | pmd_populate_kernel(&init_mm, pmd, |
155 | lm_alias(kasan_early_shadow_pte)); | |
69786cdb AR |
156 | continue; |
157 | } | |
158 | ||
159 | if (pud_none(*pud)) { | |
0207df4f AR |
160 | pmd_t *p; |
161 | ||
162 | if (slab_is_available()) { | |
163 | p = pmd_alloc(&init_mm, pud, addr); | |
164 | if (!p) | |
165 | return -ENOMEM; | |
166 | } else { | |
167 | pud_populate(&init_mm, pud, | |
168 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
169 | } | |
69786cdb AR |
170 | } |
171 | zero_pmd_populate(pud, addr, next); | |
172 | } while (pud++, addr = next, addr != end); | |
0207df4f AR |
173 | |
174 | return 0; | |
69786cdb AR |
175 | } |
176 | ||
0207df4f | 177 | static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr, |
c2febafc KS |
178 | unsigned long end) |
179 | { | |
180 | p4d_t *p4d = p4d_offset(pgd, addr); | |
181 | unsigned long next; | |
182 | ||
183 | do { | |
184 | next = p4d_addr_end(addr, end); | |
458f7920 JK |
185 | if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) { |
186 | pud_t *pud; | |
187 | pmd_t *pmd; | |
188 | ||
9577dd74 AK |
189 | p4d_populate(&init_mm, p4d, |
190 | lm_alias(kasan_early_shadow_pud)); | |
458f7920 | 191 | pud = pud_offset(p4d, addr); |
9577dd74 AK |
192 | pud_populate(&init_mm, pud, |
193 | lm_alias(kasan_early_shadow_pmd)); | |
458f7920 JK |
194 | pmd = pmd_offset(pud, addr); |
195 | pmd_populate_kernel(&init_mm, pmd, | |
9577dd74 | 196 | lm_alias(kasan_early_shadow_pte)); |
458f7920 JK |
197 | continue; |
198 | } | |
c2febafc KS |
199 | |
200 | if (p4d_none(*p4d)) { | |
0207df4f AR |
201 | pud_t *p; |
202 | ||
203 | if (slab_is_available()) { | |
204 | p = pud_alloc(&init_mm, p4d, addr); | |
205 | if (!p) | |
206 | return -ENOMEM; | |
207 | } else { | |
208 | p4d_populate(&init_mm, p4d, | |
209 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
210 | } | |
c2febafc KS |
211 | } |
212 | zero_pud_populate(p4d, addr, next); | |
213 | } while (p4d++, addr = next, addr != end); | |
0207df4f AR |
214 | |
215 | return 0; | |
c2febafc KS |
216 | } |
217 | ||
69786cdb | 218 | /** |
9577dd74 AK |
219 | * kasan_populate_early_shadow - populate shadow memory region with |
220 | * kasan_early_shadow_page | |
69786cdb AR |
221 | * @shadow_start - start of the memory range to populate |
222 | * @shadow_end - end of the memory range to populate | |
223 | */ | |
9577dd74 AK |
224 | int __ref kasan_populate_early_shadow(const void *shadow_start, |
225 | const void *shadow_end) | |
69786cdb AR |
226 | { |
227 | unsigned long addr = (unsigned long)shadow_start; | |
228 | unsigned long end = (unsigned long)shadow_end; | |
229 | pgd_t *pgd = pgd_offset_k(addr); | |
230 | unsigned long next; | |
231 | ||
232 | do { | |
233 | next = pgd_addr_end(addr, end); | |
234 | ||
235 | if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) { | |
c2febafc | 236 | p4d_t *p4d; |
69786cdb AR |
237 | pud_t *pud; |
238 | pmd_t *pmd; | |
239 | ||
240 | /* | |
9577dd74 | 241 | * kasan_early_shadow_pud should be populated with pmds |
69786cdb AR |
242 | * at this moment. |
243 | * [pud,pmd]_populate*() below needed only for | |
244 | * 3,2 - level page tables where we don't have | |
245 | * puds,pmds, so pgd_populate(), pud_populate() | |
246 | * is noops. | |
c2febafc KS |
247 | * |
248 | * The ifndef is required to avoid build breakage. | |
249 | * | |
250 | * With 5level-fixup.h, pgd_populate() is not nop and | |
9577dd74 | 251 | * we reference kasan_early_shadow_p4d. It's not defined |
c2febafc KS |
252 | * unless 5-level paging enabled. |
253 | * | |
254 | * The ifndef can be dropped once all KASAN-enabled | |
255 | * architectures will switch to pgtable-nop4d.h. | |
69786cdb | 256 | */ |
c2febafc | 257 | #ifndef __ARCH_HAS_5LEVEL_HACK |
9577dd74 AK |
258 | pgd_populate(&init_mm, pgd, |
259 | lm_alias(kasan_early_shadow_p4d)); | |
c2febafc KS |
260 | #endif |
261 | p4d = p4d_offset(pgd, addr); | |
9577dd74 AK |
262 | p4d_populate(&init_mm, p4d, |
263 | lm_alias(kasan_early_shadow_pud)); | |
c2febafc | 264 | pud = pud_offset(p4d, addr); |
9577dd74 AK |
265 | pud_populate(&init_mm, pud, |
266 | lm_alias(kasan_early_shadow_pmd)); | |
69786cdb | 267 | pmd = pmd_offset(pud, addr); |
9577dd74 AK |
268 | pmd_populate_kernel(&init_mm, pmd, |
269 | lm_alias(kasan_early_shadow_pte)); | |
69786cdb AR |
270 | continue; |
271 | } | |
272 | ||
273 | if (pgd_none(*pgd)) { | |
0207df4f AR |
274 | p4d_t *p; |
275 | ||
276 | if (slab_is_available()) { | |
277 | p = p4d_alloc(&init_mm, pgd, addr); | |
278 | if (!p) | |
279 | return -ENOMEM; | |
280 | } else { | |
281 | pgd_populate(&init_mm, pgd, | |
282 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
283 | } | |
69786cdb | 284 | } |
c2febafc | 285 | zero_p4d_populate(pgd, addr, next); |
69786cdb | 286 | } while (pgd++, addr = next, addr != end); |
0207df4f AR |
287 | |
288 | return 0; | |
289 | } | |
290 | ||
291 | static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd) | |
292 | { | |
293 | pte_t *pte; | |
294 | int i; | |
295 | ||
296 | for (i = 0; i < PTRS_PER_PTE; i++) { | |
297 | pte = pte_start + i; | |
298 | if (!pte_none(*pte)) | |
299 | return; | |
300 | } | |
301 | ||
302 | pte_free_kernel(&init_mm, (pte_t *)page_to_virt(pmd_page(*pmd))); | |
303 | pmd_clear(pmd); | |
304 | } | |
305 | ||
306 | static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud) | |
307 | { | |
308 | pmd_t *pmd; | |
309 | int i; | |
310 | ||
311 | for (i = 0; i < PTRS_PER_PMD; i++) { | |
312 | pmd = pmd_start + i; | |
313 | if (!pmd_none(*pmd)) | |
314 | return; | |
315 | } | |
316 | ||
317 | pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud))); | |
318 | pud_clear(pud); | |
319 | } | |
320 | ||
321 | static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d) | |
322 | { | |
323 | pud_t *pud; | |
324 | int i; | |
325 | ||
326 | for (i = 0; i < PTRS_PER_PUD; i++) { | |
327 | pud = pud_start + i; | |
328 | if (!pud_none(*pud)) | |
329 | return; | |
330 | } | |
331 | ||
332 | pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d))); | |
333 | p4d_clear(p4d); | |
334 | } | |
335 | ||
336 | static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd) | |
337 | { | |
338 | p4d_t *p4d; | |
339 | int i; | |
340 | ||
341 | for (i = 0; i < PTRS_PER_P4D; i++) { | |
342 | p4d = p4d_start + i; | |
343 | if (!p4d_none(*p4d)) | |
344 | return; | |
345 | } | |
346 | ||
347 | p4d_free(&init_mm, (p4d_t *)page_to_virt(pgd_page(*pgd))); | |
348 | pgd_clear(pgd); | |
349 | } | |
350 | ||
351 | static void kasan_remove_pte_table(pte_t *pte, unsigned long addr, | |
352 | unsigned long end) | |
353 | { | |
354 | unsigned long next; | |
355 | ||
356 | for (; addr < end; addr = next, pte++) { | |
357 | next = (addr + PAGE_SIZE) & PAGE_MASK; | |
358 | if (next > end) | |
359 | next = end; | |
360 | ||
361 | if (!pte_present(*pte)) | |
362 | continue; | |
363 | ||
9577dd74 | 364 | if (WARN_ON(!kasan_early_shadow_page_entry(*pte))) |
0207df4f AR |
365 | continue; |
366 | pte_clear(&init_mm, addr, pte); | |
367 | } | |
368 | } | |
369 | ||
370 | static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr, | |
371 | unsigned long end) | |
372 | { | |
373 | unsigned long next; | |
374 | ||
375 | for (; addr < end; addr = next, pmd++) { | |
376 | pte_t *pte; | |
377 | ||
378 | next = pmd_addr_end(addr, end); | |
379 | ||
380 | if (!pmd_present(*pmd)) | |
381 | continue; | |
382 | ||
383 | if (kasan_pte_table(*pmd)) { | |
384 | if (IS_ALIGNED(addr, PMD_SIZE) && | |
385 | IS_ALIGNED(next, PMD_SIZE)) | |
386 | pmd_clear(pmd); | |
387 | continue; | |
388 | } | |
389 | pte = pte_offset_kernel(pmd, addr); | |
390 | kasan_remove_pte_table(pte, addr, next); | |
391 | kasan_free_pte(pte_offset_kernel(pmd, 0), pmd); | |
392 | } | |
393 | } | |
394 | ||
395 | static void kasan_remove_pud_table(pud_t *pud, unsigned long addr, | |
396 | unsigned long end) | |
397 | { | |
398 | unsigned long next; | |
399 | ||
400 | for (; addr < end; addr = next, pud++) { | |
401 | pmd_t *pmd, *pmd_base; | |
402 | ||
403 | next = pud_addr_end(addr, end); | |
404 | ||
405 | if (!pud_present(*pud)) | |
406 | continue; | |
407 | ||
408 | if (kasan_pmd_table(*pud)) { | |
409 | if (IS_ALIGNED(addr, PUD_SIZE) && | |
410 | IS_ALIGNED(next, PUD_SIZE)) | |
411 | pud_clear(pud); | |
412 | continue; | |
413 | } | |
414 | pmd = pmd_offset(pud, addr); | |
415 | pmd_base = pmd_offset(pud, 0); | |
416 | kasan_remove_pmd_table(pmd, addr, next); | |
417 | kasan_free_pmd(pmd_base, pud); | |
418 | } | |
419 | } | |
420 | ||
421 | static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr, | |
422 | unsigned long end) | |
423 | { | |
424 | unsigned long next; | |
425 | ||
426 | for (; addr < end; addr = next, p4d++) { | |
427 | pud_t *pud; | |
428 | ||
429 | next = p4d_addr_end(addr, end); | |
430 | ||
431 | if (!p4d_present(*p4d)) | |
432 | continue; | |
433 | ||
434 | if (kasan_pud_table(*p4d)) { | |
435 | if (IS_ALIGNED(addr, P4D_SIZE) && | |
436 | IS_ALIGNED(next, P4D_SIZE)) | |
437 | p4d_clear(p4d); | |
438 | continue; | |
439 | } | |
440 | pud = pud_offset(p4d, addr); | |
441 | kasan_remove_pud_table(pud, addr, next); | |
442 | kasan_free_pud(pud_offset(p4d, 0), p4d); | |
443 | } | |
444 | } | |
445 | ||
446 | void kasan_remove_zero_shadow(void *start, unsigned long size) | |
447 | { | |
448 | unsigned long addr, end, next; | |
449 | pgd_t *pgd; | |
450 | ||
451 | addr = (unsigned long)kasan_mem_to_shadow(start); | |
452 | end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT); | |
453 | ||
454 | if (WARN_ON((unsigned long)start % | |
455 | (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) || | |
456 | WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE))) | |
457 | return; | |
458 | ||
459 | for (; addr < end; addr = next) { | |
460 | p4d_t *p4d; | |
461 | ||
462 | next = pgd_addr_end(addr, end); | |
463 | ||
464 | pgd = pgd_offset_k(addr); | |
465 | if (!pgd_present(*pgd)) | |
466 | continue; | |
467 | ||
468 | if (kasan_p4d_table(*pgd)) { | |
469 | if (IS_ALIGNED(addr, PGDIR_SIZE) && | |
470 | IS_ALIGNED(next, PGDIR_SIZE)) | |
471 | pgd_clear(pgd); | |
472 | continue; | |
473 | } | |
474 | ||
475 | p4d = p4d_offset(pgd, addr); | |
476 | kasan_remove_p4d_table(p4d, addr, next); | |
477 | kasan_free_p4d(p4d_offset(pgd, 0), pgd); | |
478 | } | |
479 | } | |
480 | ||
481 | int kasan_add_zero_shadow(void *start, unsigned long size) | |
482 | { | |
483 | int ret; | |
484 | void *shadow_start, *shadow_end; | |
485 | ||
486 | shadow_start = kasan_mem_to_shadow(start); | |
487 | shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT); | |
488 | ||
489 | if (WARN_ON((unsigned long)start % | |
490 | (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) || | |
491 | WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE))) | |
492 | return -EINVAL; | |
493 | ||
9577dd74 | 494 | ret = kasan_populate_early_shadow(shadow_start, shadow_end); |
0207df4f AR |
495 | if (ret) |
496 | kasan_remove_zero_shadow(shadow_start, | |
497 | size >> KASAN_SHADOW_SCALE_SHIFT); | |
498 | return ret; | |
69786cdb | 499 | } |