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e886bf9d | 1 | // SPDX-License-Identifier: GPL-2.0 |
69786cdb | 2 | /* |
b266e8fe | 3 | * This file contains KASAN shadow initialization code. |
69786cdb AR |
4 | * |
5 | * Copyright (c) 2015 Samsung Electronics Co., Ltd. | |
6 | * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> | |
69786cdb AR |
7 | */ |
8 | ||
57c8a661 | 9 | #include <linux/memblock.h> |
69786cdb AR |
10 | #include <linux/init.h> |
11 | #include <linux/kasan.h> | |
12 | #include <linux/kernel.h> | |
5c6a84a3 | 13 | #include <linux/mm.h> |
69786cdb | 14 | #include <linux/pfn.h> |
0207df4f | 15 | #include <linux/slab.h> |
69786cdb AR |
16 | |
17 | #include <asm/page.h> | |
18 | #include <asm/pgalloc.h> | |
19 | ||
0207df4f AR |
20 | #include "kasan.h" |
21 | ||
69786cdb AR |
22 | /* |
23 | * This page serves two purposes: | |
24 | * - It used as early shadow memory. The entire shadow region populated | |
25 | * with this page, before we will be able to setup normal shadow memory. | |
26 | * - Latter it reused it as zero shadow to cover large ranges of memory | |
27 | * that allowed to access, but not handled by kasan (vmalloc/vmemmap ...). | |
28 | */ | |
9577dd74 | 29 | unsigned char kasan_early_shadow_page[PAGE_SIZE] __page_aligned_bss; |
69786cdb | 30 | |
c2febafc | 31 | #if CONFIG_PGTABLE_LEVELS > 4 |
9577dd74 | 32 | p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss; |
0207df4f AR |
33 | static inline bool kasan_p4d_table(pgd_t pgd) |
34 | { | |
9577dd74 | 35 | return pgd_page(pgd) == virt_to_page(lm_alias(kasan_early_shadow_p4d)); |
0207df4f AR |
36 | } |
37 | #else | |
38 | static inline bool kasan_p4d_table(pgd_t pgd) | |
39 | { | |
5c0198b6 | 40 | return false; |
0207df4f | 41 | } |
c2febafc | 42 | #endif |
69786cdb | 43 | #if CONFIG_PGTABLE_LEVELS > 3 |
cb32c9c5 | 44 | pud_t kasan_early_shadow_pud[MAX_PTRS_PER_PUD] __page_aligned_bss; |
0207df4f AR |
45 | static inline bool kasan_pud_table(p4d_t p4d) |
46 | { | |
9577dd74 | 47 | return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud)); |
0207df4f AR |
48 | } |
49 | #else | |
50 | static inline bool kasan_pud_table(p4d_t p4d) | |
51 | { | |
5c0198b6 | 52 | return false; |
0207df4f | 53 | } |
69786cdb AR |
54 | #endif |
55 | #if CONFIG_PGTABLE_LEVELS > 2 | |
cb32c9c5 | 56 | pmd_t kasan_early_shadow_pmd[MAX_PTRS_PER_PMD] __page_aligned_bss; |
0207df4f AR |
57 | static inline bool kasan_pmd_table(pud_t pud) |
58 | { | |
9577dd74 | 59 | return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd)); |
0207df4f AR |
60 | } |
61 | #else | |
62 | static inline bool kasan_pmd_table(pud_t pud) | |
63 | { | |
5c0198b6 | 64 | return false; |
0207df4f | 65 | } |
69786cdb | 66 | #endif |
cb32c9c5 | 67 | pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS] |
29970dc2 | 68 | __page_aligned_bss; |
69786cdb | 69 | |
0207df4f AR |
70 | static inline bool kasan_pte_table(pmd_t pmd) |
71 | { | |
9577dd74 | 72 | return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte)); |
0207df4f AR |
73 | } |
74 | ||
9577dd74 | 75 | static inline bool kasan_early_shadow_page_entry(pte_t pte) |
0207df4f | 76 | { |
9577dd74 | 77 | return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page)); |
0207df4f AR |
78 | } |
79 | ||
69786cdb AR |
80 | static __init void *early_alloc(size_t size, int node) |
81 | { | |
8a7f97b9 MR |
82 | void *ptr = memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS), |
83 | MEMBLOCK_ALLOC_ACCESSIBLE, node); | |
84 | ||
85 | if (!ptr) | |
86 | panic("%s: Failed to allocate %zu bytes align=%zx nid=%d from=%llx\n", | |
87 | __func__, size, size, node, (u64)__pa(MAX_DMA_ADDRESS)); | |
88 | ||
89 | return ptr; | |
69786cdb AR |
90 | } |
91 | ||
0207df4f | 92 | static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr, |
69786cdb AR |
93 | unsigned long end) |
94 | { | |
95 | pte_t *pte = pte_offset_kernel(pmd, addr); | |
96 | pte_t zero_pte; | |
97 | ||
9577dd74 AK |
98 | zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)), |
99 | PAGE_KERNEL); | |
69786cdb AR |
100 | zero_pte = pte_wrprotect(zero_pte); |
101 | ||
102 | while (addr + PAGE_SIZE <= end) { | |
103 | set_pte_at(&init_mm, addr, pte, zero_pte); | |
104 | addr += PAGE_SIZE; | |
105 | pte = pte_offset_kernel(pmd, addr); | |
106 | } | |
107 | } | |
108 | ||
0207df4f | 109 | static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr, |
69786cdb AR |
110 | unsigned long end) |
111 | { | |
112 | pmd_t *pmd = pmd_offset(pud, addr); | |
113 | unsigned long next; | |
114 | ||
115 | do { | |
116 | next = pmd_addr_end(addr, end); | |
117 | ||
118 | if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) { | |
9577dd74 AK |
119 | pmd_populate_kernel(&init_mm, pmd, |
120 | lm_alias(kasan_early_shadow_pte)); | |
69786cdb AR |
121 | continue; |
122 | } | |
123 | ||
124 | if (pmd_none(*pmd)) { | |
0207df4f AR |
125 | pte_t *p; |
126 | ||
127 | if (slab_is_available()) | |
4cf58924 | 128 | p = pte_alloc_one_kernel(&init_mm); |
0207df4f AR |
129 | else |
130 | p = early_alloc(PAGE_SIZE, NUMA_NO_NODE); | |
131 | if (!p) | |
132 | return -ENOMEM; | |
133 | ||
134 | pmd_populate_kernel(&init_mm, pmd, p); | |
69786cdb AR |
135 | } |
136 | zero_pte_populate(pmd, addr, next); | |
137 | } while (pmd++, addr = next, addr != end); | |
0207df4f AR |
138 | |
139 | return 0; | |
69786cdb AR |
140 | } |
141 | ||
0207df4f | 142 | static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr, |
69786cdb AR |
143 | unsigned long end) |
144 | { | |
c2febafc | 145 | pud_t *pud = pud_offset(p4d, addr); |
69786cdb AR |
146 | unsigned long next; |
147 | ||
148 | do { | |
149 | next = pud_addr_end(addr, end); | |
150 | if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) { | |
151 | pmd_t *pmd; | |
152 | ||
9577dd74 AK |
153 | pud_populate(&init_mm, pud, |
154 | lm_alias(kasan_early_shadow_pmd)); | |
69786cdb | 155 | pmd = pmd_offset(pud, addr); |
9577dd74 AK |
156 | pmd_populate_kernel(&init_mm, pmd, |
157 | lm_alias(kasan_early_shadow_pte)); | |
69786cdb AR |
158 | continue; |
159 | } | |
160 | ||
161 | if (pud_none(*pud)) { | |
0207df4f AR |
162 | pmd_t *p; |
163 | ||
164 | if (slab_is_available()) { | |
165 | p = pmd_alloc(&init_mm, pud, addr); | |
166 | if (!p) | |
167 | return -ENOMEM; | |
168 | } else { | |
169 | pud_populate(&init_mm, pud, | |
170 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
171 | } | |
69786cdb AR |
172 | } |
173 | zero_pmd_populate(pud, addr, next); | |
174 | } while (pud++, addr = next, addr != end); | |
0207df4f AR |
175 | |
176 | return 0; | |
69786cdb AR |
177 | } |
178 | ||
0207df4f | 179 | static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr, |
c2febafc KS |
180 | unsigned long end) |
181 | { | |
182 | p4d_t *p4d = p4d_offset(pgd, addr); | |
183 | unsigned long next; | |
184 | ||
185 | do { | |
186 | next = p4d_addr_end(addr, end); | |
458f7920 JK |
187 | if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) { |
188 | pud_t *pud; | |
189 | pmd_t *pmd; | |
190 | ||
9577dd74 AK |
191 | p4d_populate(&init_mm, p4d, |
192 | lm_alias(kasan_early_shadow_pud)); | |
458f7920 | 193 | pud = pud_offset(p4d, addr); |
9577dd74 AK |
194 | pud_populate(&init_mm, pud, |
195 | lm_alias(kasan_early_shadow_pmd)); | |
458f7920 JK |
196 | pmd = pmd_offset(pud, addr); |
197 | pmd_populate_kernel(&init_mm, pmd, | |
9577dd74 | 198 | lm_alias(kasan_early_shadow_pte)); |
458f7920 JK |
199 | continue; |
200 | } | |
c2febafc KS |
201 | |
202 | if (p4d_none(*p4d)) { | |
0207df4f AR |
203 | pud_t *p; |
204 | ||
205 | if (slab_is_available()) { | |
206 | p = pud_alloc(&init_mm, p4d, addr); | |
207 | if (!p) | |
208 | return -ENOMEM; | |
209 | } else { | |
210 | p4d_populate(&init_mm, p4d, | |
211 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
212 | } | |
c2febafc KS |
213 | } |
214 | zero_pud_populate(p4d, addr, next); | |
215 | } while (p4d++, addr = next, addr != end); | |
0207df4f AR |
216 | |
217 | return 0; | |
c2febafc KS |
218 | } |
219 | ||
69786cdb | 220 | /** |
9577dd74 AK |
221 | * kasan_populate_early_shadow - populate shadow memory region with |
222 | * kasan_early_shadow_page | |
7b6889f5 YK |
223 | * @shadow_start: start of the memory range to populate |
224 | * @shadow_end: end of the memory range to populate | |
69786cdb | 225 | */ |
9577dd74 AK |
226 | int __ref kasan_populate_early_shadow(const void *shadow_start, |
227 | const void *shadow_end) | |
69786cdb AR |
228 | { |
229 | unsigned long addr = (unsigned long)shadow_start; | |
230 | unsigned long end = (unsigned long)shadow_end; | |
231 | pgd_t *pgd = pgd_offset_k(addr); | |
232 | unsigned long next; | |
233 | ||
234 | do { | |
235 | next = pgd_addr_end(addr, end); | |
236 | ||
237 | if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) { | |
c2febafc | 238 | p4d_t *p4d; |
69786cdb AR |
239 | pud_t *pud; |
240 | pmd_t *pmd; | |
241 | ||
242 | /* | |
9577dd74 | 243 | * kasan_early_shadow_pud should be populated with pmds |
69786cdb AR |
244 | * at this moment. |
245 | * [pud,pmd]_populate*() below needed only for | |
246 | * 3,2 - level page tables where we don't have | |
247 | * puds,pmds, so pgd_populate(), pud_populate() | |
248 | * is noops. | |
249 | */ | |
9577dd74 AK |
250 | pgd_populate(&init_mm, pgd, |
251 | lm_alias(kasan_early_shadow_p4d)); | |
c2febafc | 252 | p4d = p4d_offset(pgd, addr); |
9577dd74 AK |
253 | p4d_populate(&init_mm, p4d, |
254 | lm_alias(kasan_early_shadow_pud)); | |
c2febafc | 255 | pud = pud_offset(p4d, addr); |
9577dd74 AK |
256 | pud_populate(&init_mm, pud, |
257 | lm_alias(kasan_early_shadow_pmd)); | |
69786cdb | 258 | pmd = pmd_offset(pud, addr); |
9577dd74 AK |
259 | pmd_populate_kernel(&init_mm, pmd, |
260 | lm_alias(kasan_early_shadow_pte)); | |
69786cdb AR |
261 | continue; |
262 | } | |
263 | ||
264 | if (pgd_none(*pgd)) { | |
0207df4f AR |
265 | p4d_t *p; |
266 | ||
267 | if (slab_is_available()) { | |
268 | p = p4d_alloc(&init_mm, pgd, addr); | |
269 | if (!p) | |
270 | return -ENOMEM; | |
271 | } else { | |
272 | pgd_populate(&init_mm, pgd, | |
273 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
274 | } | |
69786cdb | 275 | } |
c2febafc | 276 | zero_p4d_populate(pgd, addr, next); |
69786cdb | 277 | } while (pgd++, addr = next, addr != end); |
0207df4f AR |
278 | |
279 | return 0; | |
280 | } | |
281 | ||
282 | static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd) | |
283 | { | |
284 | pte_t *pte; | |
285 | int i; | |
286 | ||
287 | for (i = 0; i < PTRS_PER_PTE; i++) { | |
288 | pte = pte_start + i; | |
289 | if (!pte_none(*pte)) | |
290 | return; | |
291 | } | |
292 | ||
293 | pte_free_kernel(&init_mm, (pte_t *)page_to_virt(pmd_page(*pmd))); | |
294 | pmd_clear(pmd); | |
295 | } | |
296 | ||
297 | static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud) | |
298 | { | |
299 | pmd_t *pmd; | |
300 | int i; | |
301 | ||
302 | for (i = 0; i < PTRS_PER_PMD; i++) { | |
303 | pmd = pmd_start + i; | |
304 | if (!pmd_none(*pmd)) | |
305 | return; | |
306 | } | |
307 | ||
308 | pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud))); | |
309 | pud_clear(pud); | |
310 | } | |
311 | ||
312 | static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d) | |
313 | { | |
314 | pud_t *pud; | |
315 | int i; | |
316 | ||
317 | for (i = 0; i < PTRS_PER_PUD; i++) { | |
318 | pud = pud_start + i; | |
319 | if (!pud_none(*pud)) | |
320 | return; | |
321 | } | |
322 | ||
323 | pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d))); | |
324 | p4d_clear(p4d); | |
325 | } | |
326 | ||
327 | static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd) | |
328 | { | |
329 | p4d_t *p4d; | |
330 | int i; | |
331 | ||
332 | for (i = 0; i < PTRS_PER_P4D; i++) { | |
333 | p4d = p4d_start + i; | |
334 | if (!p4d_none(*p4d)) | |
335 | return; | |
336 | } | |
337 | ||
338 | p4d_free(&init_mm, (p4d_t *)page_to_virt(pgd_page(*pgd))); | |
339 | pgd_clear(pgd); | |
340 | } | |
341 | ||
342 | static void kasan_remove_pte_table(pte_t *pte, unsigned long addr, | |
343 | unsigned long end) | |
344 | { | |
345 | unsigned long next; | |
346 | ||
347 | for (; addr < end; addr = next, pte++) { | |
348 | next = (addr + PAGE_SIZE) & PAGE_MASK; | |
349 | if (next > end) | |
350 | next = end; | |
351 | ||
352 | if (!pte_present(*pte)) | |
353 | continue; | |
354 | ||
9577dd74 | 355 | if (WARN_ON(!kasan_early_shadow_page_entry(*pte))) |
0207df4f AR |
356 | continue; |
357 | pte_clear(&init_mm, addr, pte); | |
358 | } | |
359 | } | |
360 | ||
361 | static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr, | |
362 | unsigned long end) | |
363 | { | |
364 | unsigned long next; | |
365 | ||
366 | for (; addr < end; addr = next, pmd++) { | |
367 | pte_t *pte; | |
368 | ||
369 | next = pmd_addr_end(addr, end); | |
370 | ||
371 | if (!pmd_present(*pmd)) | |
372 | continue; | |
373 | ||
374 | if (kasan_pte_table(*pmd)) { | |
375 | if (IS_ALIGNED(addr, PMD_SIZE) && | |
a11a496e | 376 | IS_ALIGNED(next, PMD_SIZE)) { |
0207df4f | 377 | pmd_clear(pmd); |
a11a496e LC |
378 | continue; |
379 | } | |
0207df4f AR |
380 | } |
381 | pte = pte_offset_kernel(pmd, addr); | |
382 | kasan_remove_pte_table(pte, addr, next); | |
383 | kasan_free_pte(pte_offset_kernel(pmd, 0), pmd); | |
384 | } | |
385 | } | |
386 | ||
387 | static void kasan_remove_pud_table(pud_t *pud, unsigned long addr, | |
388 | unsigned long end) | |
389 | { | |
390 | unsigned long next; | |
391 | ||
392 | for (; addr < end; addr = next, pud++) { | |
393 | pmd_t *pmd, *pmd_base; | |
394 | ||
395 | next = pud_addr_end(addr, end); | |
396 | ||
397 | if (!pud_present(*pud)) | |
398 | continue; | |
399 | ||
400 | if (kasan_pmd_table(*pud)) { | |
401 | if (IS_ALIGNED(addr, PUD_SIZE) && | |
a11a496e | 402 | IS_ALIGNED(next, PUD_SIZE)) { |
0207df4f | 403 | pud_clear(pud); |
a11a496e LC |
404 | continue; |
405 | } | |
0207df4f AR |
406 | } |
407 | pmd = pmd_offset(pud, addr); | |
408 | pmd_base = pmd_offset(pud, 0); | |
409 | kasan_remove_pmd_table(pmd, addr, next); | |
410 | kasan_free_pmd(pmd_base, pud); | |
411 | } | |
412 | } | |
413 | ||
414 | static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr, | |
415 | unsigned long end) | |
416 | { | |
417 | unsigned long next; | |
418 | ||
419 | for (; addr < end; addr = next, p4d++) { | |
420 | pud_t *pud; | |
421 | ||
422 | next = p4d_addr_end(addr, end); | |
423 | ||
424 | if (!p4d_present(*p4d)) | |
425 | continue; | |
426 | ||
427 | if (kasan_pud_table(*p4d)) { | |
428 | if (IS_ALIGNED(addr, P4D_SIZE) && | |
a11a496e | 429 | IS_ALIGNED(next, P4D_SIZE)) { |
0207df4f | 430 | p4d_clear(p4d); |
a11a496e LC |
431 | continue; |
432 | } | |
0207df4f AR |
433 | } |
434 | pud = pud_offset(p4d, addr); | |
435 | kasan_remove_pud_table(pud, addr, next); | |
436 | kasan_free_pud(pud_offset(p4d, 0), p4d); | |
437 | } | |
438 | } | |
439 | ||
440 | void kasan_remove_zero_shadow(void *start, unsigned long size) | |
441 | { | |
442 | unsigned long addr, end, next; | |
443 | pgd_t *pgd; | |
444 | ||
445 | addr = (unsigned long)kasan_mem_to_shadow(start); | |
446 | end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT); | |
447 | ||
affc3f07 AK |
448 | if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) || |
449 | WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE)) | |
0207df4f AR |
450 | return; |
451 | ||
452 | for (; addr < end; addr = next) { | |
453 | p4d_t *p4d; | |
454 | ||
455 | next = pgd_addr_end(addr, end); | |
456 | ||
457 | pgd = pgd_offset_k(addr); | |
458 | if (!pgd_present(*pgd)) | |
459 | continue; | |
460 | ||
461 | if (kasan_p4d_table(*pgd)) { | |
462 | if (IS_ALIGNED(addr, PGDIR_SIZE) && | |
a11a496e | 463 | IS_ALIGNED(next, PGDIR_SIZE)) { |
0207df4f | 464 | pgd_clear(pgd); |
a11a496e LC |
465 | continue; |
466 | } | |
0207df4f AR |
467 | } |
468 | ||
469 | p4d = p4d_offset(pgd, addr); | |
470 | kasan_remove_p4d_table(p4d, addr, next); | |
471 | kasan_free_p4d(p4d_offset(pgd, 0), pgd); | |
472 | } | |
473 | } | |
474 | ||
475 | int kasan_add_zero_shadow(void *start, unsigned long size) | |
476 | { | |
477 | int ret; | |
478 | void *shadow_start, *shadow_end; | |
479 | ||
480 | shadow_start = kasan_mem_to_shadow(start); | |
481 | shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT); | |
482 | ||
affc3f07 AK |
483 | if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) || |
484 | WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE)) | |
0207df4f AR |
485 | return -EINVAL; |
486 | ||
9577dd74 | 487 | ret = kasan_populate_early_shadow(shadow_start, shadow_end); |
0207df4f | 488 | if (ret) |
5dabd171 | 489 | kasan_remove_zero_shadow(start, size); |
0207df4f | 490 | return ret; |
69786cdb | 491 | } |