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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 | { | |
5c0198b6 | 45 | return false; |
0207df4f | 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 | { | |
5c0198b6 | 57 | return false; |
0207df4f | 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 | { | |
5c0198b6 | 69 | return false; |
0207df4f | 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 | { | |
8a7f97b9 MR |
86 | void *ptr = memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS), |
87 | MEMBLOCK_ALLOC_ACCESSIBLE, node); | |
88 | ||
89 | if (!ptr) | |
90 | panic("%s: Failed to allocate %zu bytes align=%zx nid=%d from=%llx\n", | |
91 | __func__, size, size, node, (u64)__pa(MAX_DMA_ADDRESS)); | |
92 | ||
93 | return ptr; | |
69786cdb AR |
94 | } |
95 | ||
0207df4f | 96 | static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr, |
69786cdb AR |
97 | unsigned long end) |
98 | { | |
99 | pte_t *pte = pte_offset_kernel(pmd, addr); | |
100 | pte_t zero_pte; | |
101 | ||
9577dd74 AK |
102 | zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)), |
103 | PAGE_KERNEL); | |
69786cdb AR |
104 | zero_pte = pte_wrprotect(zero_pte); |
105 | ||
106 | while (addr + PAGE_SIZE <= end) { | |
107 | set_pte_at(&init_mm, addr, pte, zero_pte); | |
108 | addr += PAGE_SIZE; | |
109 | pte = pte_offset_kernel(pmd, addr); | |
110 | } | |
111 | } | |
112 | ||
0207df4f | 113 | static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr, |
69786cdb AR |
114 | unsigned long end) |
115 | { | |
116 | pmd_t *pmd = pmd_offset(pud, addr); | |
117 | unsigned long next; | |
118 | ||
119 | do { | |
120 | next = pmd_addr_end(addr, end); | |
121 | ||
122 | if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) { | |
9577dd74 AK |
123 | pmd_populate_kernel(&init_mm, pmd, |
124 | lm_alias(kasan_early_shadow_pte)); | |
69786cdb AR |
125 | continue; |
126 | } | |
127 | ||
128 | if (pmd_none(*pmd)) { | |
0207df4f AR |
129 | pte_t *p; |
130 | ||
131 | if (slab_is_available()) | |
4cf58924 | 132 | p = pte_alloc_one_kernel(&init_mm); |
0207df4f AR |
133 | else |
134 | p = early_alloc(PAGE_SIZE, NUMA_NO_NODE); | |
135 | if (!p) | |
136 | return -ENOMEM; | |
137 | ||
138 | pmd_populate_kernel(&init_mm, pmd, p); | |
69786cdb AR |
139 | } |
140 | zero_pte_populate(pmd, addr, next); | |
141 | } while (pmd++, addr = next, addr != end); | |
0207df4f AR |
142 | |
143 | return 0; | |
69786cdb AR |
144 | } |
145 | ||
0207df4f | 146 | static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr, |
69786cdb AR |
147 | unsigned long end) |
148 | { | |
c2febafc | 149 | pud_t *pud = pud_offset(p4d, addr); |
69786cdb AR |
150 | unsigned long next; |
151 | ||
152 | do { | |
153 | next = pud_addr_end(addr, end); | |
154 | if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) { | |
155 | pmd_t *pmd; | |
156 | ||
9577dd74 AK |
157 | pud_populate(&init_mm, pud, |
158 | lm_alias(kasan_early_shadow_pmd)); | |
69786cdb | 159 | pmd = pmd_offset(pud, addr); |
9577dd74 AK |
160 | pmd_populate_kernel(&init_mm, pmd, |
161 | lm_alias(kasan_early_shadow_pte)); | |
69786cdb AR |
162 | continue; |
163 | } | |
164 | ||
165 | if (pud_none(*pud)) { | |
0207df4f AR |
166 | pmd_t *p; |
167 | ||
168 | if (slab_is_available()) { | |
169 | p = pmd_alloc(&init_mm, pud, addr); | |
170 | if (!p) | |
171 | return -ENOMEM; | |
172 | } else { | |
173 | pud_populate(&init_mm, pud, | |
174 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
175 | } | |
69786cdb AR |
176 | } |
177 | zero_pmd_populate(pud, addr, next); | |
178 | } while (pud++, addr = next, addr != end); | |
0207df4f AR |
179 | |
180 | return 0; | |
69786cdb AR |
181 | } |
182 | ||
0207df4f | 183 | static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr, |
c2febafc KS |
184 | unsigned long end) |
185 | { | |
186 | p4d_t *p4d = p4d_offset(pgd, addr); | |
187 | unsigned long next; | |
188 | ||
189 | do { | |
190 | next = p4d_addr_end(addr, end); | |
458f7920 JK |
191 | if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) { |
192 | pud_t *pud; | |
193 | pmd_t *pmd; | |
194 | ||
9577dd74 AK |
195 | p4d_populate(&init_mm, p4d, |
196 | lm_alias(kasan_early_shadow_pud)); | |
458f7920 | 197 | pud = pud_offset(p4d, addr); |
9577dd74 AK |
198 | pud_populate(&init_mm, pud, |
199 | lm_alias(kasan_early_shadow_pmd)); | |
458f7920 JK |
200 | pmd = pmd_offset(pud, addr); |
201 | pmd_populate_kernel(&init_mm, pmd, | |
9577dd74 | 202 | lm_alias(kasan_early_shadow_pte)); |
458f7920 JK |
203 | continue; |
204 | } | |
c2febafc KS |
205 | |
206 | if (p4d_none(*p4d)) { | |
0207df4f AR |
207 | pud_t *p; |
208 | ||
209 | if (slab_is_available()) { | |
210 | p = pud_alloc(&init_mm, p4d, addr); | |
211 | if (!p) | |
212 | return -ENOMEM; | |
213 | } else { | |
214 | p4d_populate(&init_mm, p4d, | |
215 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
216 | } | |
c2febafc KS |
217 | } |
218 | zero_pud_populate(p4d, addr, next); | |
219 | } while (p4d++, addr = next, addr != end); | |
0207df4f AR |
220 | |
221 | return 0; | |
c2febafc KS |
222 | } |
223 | ||
69786cdb | 224 | /** |
9577dd74 AK |
225 | * kasan_populate_early_shadow - populate shadow memory region with |
226 | * kasan_early_shadow_page | |
69786cdb AR |
227 | * @shadow_start - start of the memory range to populate |
228 | * @shadow_end - end of the memory range to populate | |
229 | */ | |
9577dd74 AK |
230 | int __ref kasan_populate_early_shadow(const void *shadow_start, |
231 | const void *shadow_end) | |
69786cdb AR |
232 | { |
233 | unsigned long addr = (unsigned long)shadow_start; | |
234 | unsigned long end = (unsigned long)shadow_end; | |
235 | pgd_t *pgd = pgd_offset_k(addr); | |
236 | unsigned long next; | |
237 | ||
238 | do { | |
239 | next = pgd_addr_end(addr, end); | |
240 | ||
241 | if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) { | |
c2febafc | 242 | p4d_t *p4d; |
69786cdb AR |
243 | pud_t *pud; |
244 | pmd_t *pmd; | |
245 | ||
246 | /* | |
9577dd74 | 247 | * kasan_early_shadow_pud should be populated with pmds |
69786cdb AR |
248 | * at this moment. |
249 | * [pud,pmd]_populate*() below needed only for | |
250 | * 3,2 - level page tables where we don't have | |
251 | * puds,pmds, so pgd_populate(), pud_populate() | |
252 | * is noops. | |
c2febafc KS |
253 | * |
254 | * The ifndef is required to avoid build breakage. | |
255 | * | |
256 | * With 5level-fixup.h, pgd_populate() is not nop and | |
9577dd74 | 257 | * we reference kasan_early_shadow_p4d. It's not defined |
c2febafc KS |
258 | * unless 5-level paging enabled. |
259 | * | |
260 | * The ifndef can be dropped once all KASAN-enabled | |
261 | * architectures will switch to pgtable-nop4d.h. | |
69786cdb | 262 | */ |
c2febafc | 263 | #ifndef __ARCH_HAS_5LEVEL_HACK |
9577dd74 AK |
264 | pgd_populate(&init_mm, pgd, |
265 | lm_alias(kasan_early_shadow_p4d)); | |
c2febafc KS |
266 | #endif |
267 | p4d = p4d_offset(pgd, addr); | |
9577dd74 AK |
268 | p4d_populate(&init_mm, p4d, |
269 | lm_alias(kasan_early_shadow_pud)); | |
c2febafc | 270 | pud = pud_offset(p4d, addr); |
9577dd74 AK |
271 | pud_populate(&init_mm, pud, |
272 | lm_alias(kasan_early_shadow_pmd)); | |
69786cdb | 273 | pmd = pmd_offset(pud, addr); |
9577dd74 AK |
274 | pmd_populate_kernel(&init_mm, pmd, |
275 | lm_alias(kasan_early_shadow_pte)); | |
69786cdb AR |
276 | continue; |
277 | } | |
278 | ||
279 | if (pgd_none(*pgd)) { | |
0207df4f AR |
280 | p4d_t *p; |
281 | ||
282 | if (slab_is_available()) { | |
283 | p = p4d_alloc(&init_mm, pgd, addr); | |
284 | if (!p) | |
285 | return -ENOMEM; | |
286 | } else { | |
287 | pgd_populate(&init_mm, pgd, | |
288 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
289 | } | |
69786cdb | 290 | } |
c2febafc | 291 | zero_p4d_populate(pgd, addr, next); |
69786cdb | 292 | } while (pgd++, addr = next, addr != end); |
0207df4f AR |
293 | |
294 | return 0; | |
295 | } | |
296 | ||
297 | static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd) | |
298 | { | |
299 | pte_t *pte; | |
300 | int i; | |
301 | ||
302 | for (i = 0; i < PTRS_PER_PTE; i++) { | |
303 | pte = pte_start + i; | |
304 | if (!pte_none(*pte)) | |
305 | return; | |
306 | } | |
307 | ||
308 | pte_free_kernel(&init_mm, (pte_t *)page_to_virt(pmd_page(*pmd))); | |
309 | pmd_clear(pmd); | |
310 | } | |
311 | ||
312 | static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud) | |
313 | { | |
314 | pmd_t *pmd; | |
315 | int i; | |
316 | ||
317 | for (i = 0; i < PTRS_PER_PMD; i++) { | |
318 | pmd = pmd_start + i; | |
319 | if (!pmd_none(*pmd)) | |
320 | return; | |
321 | } | |
322 | ||
323 | pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud))); | |
324 | pud_clear(pud); | |
325 | } | |
326 | ||
327 | static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d) | |
328 | { | |
329 | pud_t *pud; | |
330 | int i; | |
331 | ||
332 | for (i = 0; i < PTRS_PER_PUD; i++) { | |
333 | pud = pud_start + i; | |
334 | if (!pud_none(*pud)) | |
335 | return; | |
336 | } | |
337 | ||
338 | pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d))); | |
339 | p4d_clear(p4d); | |
340 | } | |
341 | ||
342 | static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd) | |
343 | { | |
344 | p4d_t *p4d; | |
345 | int i; | |
346 | ||
347 | for (i = 0; i < PTRS_PER_P4D; i++) { | |
348 | p4d = p4d_start + i; | |
349 | if (!p4d_none(*p4d)) | |
350 | return; | |
351 | } | |
352 | ||
353 | p4d_free(&init_mm, (p4d_t *)page_to_virt(pgd_page(*pgd))); | |
354 | pgd_clear(pgd); | |
355 | } | |
356 | ||
357 | static void kasan_remove_pte_table(pte_t *pte, unsigned long addr, | |
358 | unsigned long end) | |
359 | { | |
360 | unsigned long next; | |
361 | ||
362 | for (; addr < end; addr = next, pte++) { | |
363 | next = (addr + PAGE_SIZE) & PAGE_MASK; | |
364 | if (next > end) | |
365 | next = end; | |
366 | ||
367 | if (!pte_present(*pte)) | |
368 | continue; | |
369 | ||
9577dd74 | 370 | if (WARN_ON(!kasan_early_shadow_page_entry(*pte))) |
0207df4f AR |
371 | continue; |
372 | pte_clear(&init_mm, addr, pte); | |
373 | } | |
374 | } | |
375 | ||
376 | static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr, | |
377 | unsigned long end) | |
378 | { | |
379 | unsigned long next; | |
380 | ||
381 | for (; addr < end; addr = next, pmd++) { | |
382 | pte_t *pte; | |
383 | ||
384 | next = pmd_addr_end(addr, end); | |
385 | ||
386 | if (!pmd_present(*pmd)) | |
387 | continue; | |
388 | ||
389 | if (kasan_pte_table(*pmd)) { | |
390 | if (IS_ALIGNED(addr, PMD_SIZE) && | |
391 | IS_ALIGNED(next, PMD_SIZE)) | |
392 | pmd_clear(pmd); | |
393 | continue; | |
394 | } | |
395 | pte = pte_offset_kernel(pmd, addr); | |
396 | kasan_remove_pte_table(pte, addr, next); | |
397 | kasan_free_pte(pte_offset_kernel(pmd, 0), pmd); | |
398 | } | |
399 | } | |
400 | ||
401 | static void kasan_remove_pud_table(pud_t *pud, unsigned long addr, | |
402 | unsigned long end) | |
403 | { | |
404 | unsigned long next; | |
405 | ||
406 | for (; addr < end; addr = next, pud++) { | |
407 | pmd_t *pmd, *pmd_base; | |
408 | ||
409 | next = pud_addr_end(addr, end); | |
410 | ||
411 | if (!pud_present(*pud)) | |
412 | continue; | |
413 | ||
414 | if (kasan_pmd_table(*pud)) { | |
415 | if (IS_ALIGNED(addr, PUD_SIZE) && | |
416 | IS_ALIGNED(next, PUD_SIZE)) | |
417 | pud_clear(pud); | |
418 | continue; | |
419 | } | |
420 | pmd = pmd_offset(pud, addr); | |
421 | pmd_base = pmd_offset(pud, 0); | |
422 | kasan_remove_pmd_table(pmd, addr, next); | |
423 | kasan_free_pmd(pmd_base, pud); | |
424 | } | |
425 | } | |
426 | ||
427 | static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr, | |
428 | unsigned long end) | |
429 | { | |
430 | unsigned long next; | |
431 | ||
432 | for (; addr < end; addr = next, p4d++) { | |
433 | pud_t *pud; | |
434 | ||
435 | next = p4d_addr_end(addr, end); | |
436 | ||
437 | if (!p4d_present(*p4d)) | |
438 | continue; | |
439 | ||
440 | if (kasan_pud_table(*p4d)) { | |
441 | if (IS_ALIGNED(addr, P4D_SIZE) && | |
442 | IS_ALIGNED(next, P4D_SIZE)) | |
443 | p4d_clear(p4d); | |
444 | continue; | |
445 | } | |
446 | pud = pud_offset(p4d, addr); | |
447 | kasan_remove_pud_table(pud, addr, next); | |
448 | kasan_free_pud(pud_offset(p4d, 0), p4d); | |
449 | } | |
450 | } | |
451 | ||
452 | void kasan_remove_zero_shadow(void *start, unsigned long size) | |
453 | { | |
454 | unsigned long addr, end, next; | |
455 | pgd_t *pgd; | |
456 | ||
457 | addr = (unsigned long)kasan_mem_to_shadow(start); | |
458 | end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT); | |
459 | ||
460 | if (WARN_ON((unsigned long)start % | |
461 | (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) || | |
462 | WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE))) | |
463 | return; | |
464 | ||
465 | for (; addr < end; addr = next) { | |
466 | p4d_t *p4d; | |
467 | ||
468 | next = pgd_addr_end(addr, end); | |
469 | ||
470 | pgd = pgd_offset_k(addr); | |
471 | if (!pgd_present(*pgd)) | |
472 | continue; | |
473 | ||
474 | if (kasan_p4d_table(*pgd)) { | |
475 | if (IS_ALIGNED(addr, PGDIR_SIZE) && | |
476 | IS_ALIGNED(next, PGDIR_SIZE)) | |
477 | pgd_clear(pgd); | |
478 | continue; | |
479 | } | |
480 | ||
481 | p4d = p4d_offset(pgd, addr); | |
482 | kasan_remove_p4d_table(p4d, addr, next); | |
483 | kasan_free_p4d(p4d_offset(pgd, 0), pgd); | |
484 | } | |
485 | } | |
486 | ||
487 | int kasan_add_zero_shadow(void *start, unsigned long size) | |
488 | { | |
489 | int ret; | |
490 | void *shadow_start, *shadow_end; | |
491 | ||
492 | shadow_start = kasan_mem_to_shadow(start); | |
493 | shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT); | |
494 | ||
495 | if (WARN_ON((unsigned long)start % | |
496 | (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) || | |
497 | WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE))) | |
498 | return -EINVAL; | |
499 | ||
9577dd74 | 500 | ret = kasan_populate_early_shadow(shadow_start, shadow_end); |
0207df4f AR |
501 | if (ret) |
502 | kasan_remove_zero_shadow(shadow_start, | |
503 | size >> KASAN_SHADOW_SCALE_SHIFT); | |
504 | return ret; | |
69786cdb | 505 | } |