Commit | Line | Data |
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69786cdb AR |
1 | /* |
2 | * This file contains some kasan initialization code. | |
3 | * | |
4 | * Copyright (c) 2015 Samsung Electronics Co., Ltd. | |
5 | * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | */ | |
12 | ||
13 | #include <linux/bootmem.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/kasan.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/memblock.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 | */ | |
34 | unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss; | |
35 | ||
c2febafc | 36 | #if CONFIG_PGTABLE_LEVELS > 4 |
c65e774f | 37 | p4d_t kasan_zero_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss; |
0207df4f AR |
38 | static inline bool kasan_p4d_table(pgd_t pgd) |
39 | { | |
40 | return pgd_page(pgd) == virt_to_page(lm_alias(kasan_zero_p4d)); | |
41 | } | |
42 | #else | |
43 | static inline bool kasan_p4d_table(pgd_t pgd) | |
44 | { | |
45 | return 0; | |
46 | } | |
c2febafc | 47 | #endif |
69786cdb AR |
48 | #if CONFIG_PGTABLE_LEVELS > 3 |
49 | pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss; | |
0207df4f AR |
50 | static inline bool kasan_pud_table(p4d_t p4d) |
51 | { | |
52 | return p4d_page(p4d) == virt_to_page(lm_alias(kasan_zero_pud)); | |
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 | |
61 | pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss; | |
0207df4f AR |
62 | static inline bool kasan_pmd_table(pud_t pud) |
63 | { | |
64 | return pud_page(pud) == virt_to_page(lm_alias(kasan_zero_pmd)); | |
65 | } | |
66 | #else | |
67 | static inline bool kasan_pmd_table(pud_t pud) | |
68 | { | |
69 | return 0; | |
70 | } | |
69786cdb AR |
71 | #endif |
72 | pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss; | |
73 | ||
0207df4f AR |
74 | static inline bool kasan_pte_table(pmd_t pmd) |
75 | { | |
76 | return pmd_page(pmd) == virt_to_page(lm_alias(kasan_zero_pte)); | |
77 | } | |
78 | ||
79 | static inline bool kasan_zero_page_entry(pte_t pte) | |
80 | { | |
81 | return pte_page(pte) == virt_to_page(lm_alias(kasan_zero_page)); | |
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), |
69786cdb AR |
87 | BOOTMEM_ALLOC_ACCESSIBLE, node); |
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 | ||
5c6a84a3 | 96 | zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_zero_page)), PAGE_KERNEL); |
69786cdb AR |
97 | zero_pte = pte_wrprotect(zero_pte); |
98 | ||
99 | while (addr + PAGE_SIZE <= end) { | |
100 | set_pte_at(&init_mm, addr, pte, zero_pte); | |
101 | addr += PAGE_SIZE; | |
102 | pte = pte_offset_kernel(pmd, addr); | |
103 | } | |
104 | } | |
105 | ||
0207df4f | 106 | static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr, |
69786cdb AR |
107 | unsigned long end) |
108 | { | |
109 | pmd_t *pmd = pmd_offset(pud, addr); | |
110 | unsigned long next; | |
111 | ||
112 | do { | |
113 | next = pmd_addr_end(addr, end); | |
114 | ||
115 | if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) { | |
5c6a84a3 | 116 | pmd_populate_kernel(&init_mm, pmd, lm_alias(kasan_zero_pte)); |
69786cdb AR |
117 | continue; |
118 | } | |
119 | ||
120 | if (pmd_none(*pmd)) { | |
0207df4f AR |
121 | pte_t *p; |
122 | ||
123 | if (slab_is_available()) | |
124 | p = pte_alloc_one_kernel(&init_mm, addr); | |
125 | else | |
126 | p = early_alloc(PAGE_SIZE, NUMA_NO_NODE); | |
127 | if (!p) | |
128 | return -ENOMEM; | |
129 | ||
130 | pmd_populate_kernel(&init_mm, pmd, p); | |
69786cdb AR |
131 | } |
132 | zero_pte_populate(pmd, addr, next); | |
133 | } while (pmd++, addr = next, addr != end); | |
0207df4f AR |
134 | |
135 | return 0; | |
69786cdb AR |
136 | } |
137 | ||
0207df4f | 138 | static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr, |
69786cdb AR |
139 | unsigned long end) |
140 | { | |
c2febafc | 141 | pud_t *pud = pud_offset(p4d, addr); |
69786cdb AR |
142 | unsigned long next; |
143 | ||
144 | do { | |
145 | next = pud_addr_end(addr, end); | |
146 | if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) { | |
147 | pmd_t *pmd; | |
148 | ||
5c6a84a3 | 149 | pud_populate(&init_mm, pud, lm_alias(kasan_zero_pmd)); |
69786cdb | 150 | pmd = pmd_offset(pud, addr); |
5c6a84a3 | 151 | pmd_populate_kernel(&init_mm, pmd, lm_alias(kasan_zero_pte)); |
69786cdb AR |
152 | continue; |
153 | } | |
154 | ||
155 | if (pud_none(*pud)) { | |
0207df4f AR |
156 | pmd_t *p; |
157 | ||
158 | if (slab_is_available()) { | |
159 | p = pmd_alloc(&init_mm, pud, addr); | |
160 | if (!p) | |
161 | return -ENOMEM; | |
162 | } else { | |
163 | pud_populate(&init_mm, pud, | |
164 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
165 | } | |
69786cdb AR |
166 | } |
167 | zero_pmd_populate(pud, addr, next); | |
168 | } while (pud++, addr = next, addr != end); | |
0207df4f AR |
169 | |
170 | return 0; | |
69786cdb AR |
171 | } |
172 | ||
0207df4f | 173 | static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr, |
c2febafc KS |
174 | unsigned long end) |
175 | { | |
176 | p4d_t *p4d = p4d_offset(pgd, addr); | |
177 | unsigned long next; | |
178 | ||
179 | do { | |
180 | next = p4d_addr_end(addr, end); | |
458f7920 JK |
181 | if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) { |
182 | pud_t *pud; | |
183 | pmd_t *pmd; | |
184 | ||
185 | p4d_populate(&init_mm, p4d, lm_alias(kasan_zero_pud)); | |
186 | pud = pud_offset(p4d, addr); | |
187 | pud_populate(&init_mm, pud, lm_alias(kasan_zero_pmd)); | |
188 | pmd = pmd_offset(pud, addr); | |
189 | pmd_populate_kernel(&init_mm, pmd, | |
190 | lm_alias(kasan_zero_pte)); | |
191 | continue; | |
192 | } | |
c2febafc KS |
193 | |
194 | if (p4d_none(*p4d)) { | |
0207df4f AR |
195 | pud_t *p; |
196 | ||
197 | if (slab_is_available()) { | |
198 | p = pud_alloc(&init_mm, p4d, addr); | |
199 | if (!p) | |
200 | return -ENOMEM; | |
201 | } else { | |
202 | p4d_populate(&init_mm, p4d, | |
203 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
204 | } | |
c2febafc KS |
205 | } |
206 | zero_pud_populate(p4d, addr, next); | |
207 | } while (p4d++, addr = next, addr != end); | |
0207df4f AR |
208 | |
209 | return 0; | |
c2febafc KS |
210 | } |
211 | ||
69786cdb AR |
212 | /** |
213 | * kasan_populate_zero_shadow - populate shadow memory region with | |
214 | * kasan_zero_page | |
215 | * @shadow_start - start of the memory range to populate | |
216 | * @shadow_end - end of the memory range to populate | |
217 | */ | |
0207df4f | 218 | int __ref kasan_populate_zero_shadow(const void *shadow_start, |
69786cdb AR |
219 | const void *shadow_end) |
220 | { | |
221 | unsigned long addr = (unsigned long)shadow_start; | |
222 | unsigned long end = (unsigned long)shadow_end; | |
223 | pgd_t *pgd = pgd_offset_k(addr); | |
224 | unsigned long next; | |
225 | ||
226 | do { | |
227 | next = pgd_addr_end(addr, end); | |
228 | ||
229 | if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) { | |
c2febafc | 230 | p4d_t *p4d; |
69786cdb AR |
231 | pud_t *pud; |
232 | pmd_t *pmd; | |
233 | ||
234 | /* | |
235 | * kasan_zero_pud should be populated with pmds | |
236 | * at this moment. | |
237 | * [pud,pmd]_populate*() below needed only for | |
238 | * 3,2 - level page tables where we don't have | |
239 | * puds,pmds, so pgd_populate(), pud_populate() | |
240 | * is noops. | |
c2febafc KS |
241 | * |
242 | * The ifndef is required to avoid build breakage. | |
243 | * | |
244 | * With 5level-fixup.h, pgd_populate() is not nop and | |
245 | * we reference kasan_zero_p4d. It's not defined | |
246 | * unless 5-level paging enabled. | |
247 | * | |
248 | * The ifndef can be dropped once all KASAN-enabled | |
249 | * architectures will switch to pgtable-nop4d.h. | |
69786cdb | 250 | */ |
c2febafc KS |
251 | #ifndef __ARCH_HAS_5LEVEL_HACK |
252 | pgd_populate(&init_mm, pgd, lm_alias(kasan_zero_p4d)); | |
253 | #endif | |
254 | p4d = p4d_offset(pgd, addr); | |
255 | p4d_populate(&init_mm, p4d, lm_alias(kasan_zero_pud)); | |
256 | pud = pud_offset(p4d, addr); | |
5c6a84a3 | 257 | pud_populate(&init_mm, pud, lm_alias(kasan_zero_pmd)); |
69786cdb | 258 | pmd = pmd_offset(pud, addr); |
5c6a84a3 | 259 | pmd_populate_kernel(&init_mm, pmd, lm_alias(kasan_zero_pte)); |
69786cdb AR |
260 | continue; |
261 | } | |
262 | ||
263 | if (pgd_none(*pgd)) { | |
0207df4f AR |
264 | p4d_t *p; |
265 | ||
266 | if (slab_is_available()) { | |
267 | p = p4d_alloc(&init_mm, pgd, addr); | |
268 | if (!p) | |
269 | return -ENOMEM; | |
270 | } else { | |
271 | pgd_populate(&init_mm, pgd, | |
272 | early_alloc(PAGE_SIZE, NUMA_NO_NODE)); | |
273 | } | |
69786cdb | 274 | } |
c2febafc | 275 | zero_p4d_populate(pgd, addr, next); |
69786cdb | 276 | } while (pgd++, addr = next, addr != end); |
0207df4f AR |
277 | |
278 | return 0; | |
279 | } | |
280 | ||
281 | static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd) | |
282 | { | |
283 | pte_t *pte; | |
284 | int i; | |
285 | ||
286 | for (i = 0; i < PTRS_PER_PTE; i++) { | |
287 | pte = pte_start + i; | |
288 | if (!pte_none(*pte)) | |
289 | return; | |
290 | } | |
291 | ||
292 | pte_free_kernel(&init_mm, (pte_t *)page_to_virt(pmd_page(*pmd))); | |
293 | pmd_clear(pmd); | |
294 | } | |
295 | ||
296 | static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud) | |
297 | { | |
298 | pmd_t *pmd; | |
299 | int i; | |
300 | ||
301 | for (i = 0; i < PTRS_PER_PMD; i++) { | |
302 | pmd = pmd_start + i; | |
303 | if (!pmd_none(*pmd)) | |
304 | return; | |
305 | } | |
306 | ||
307 | pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud))); | |
308 | pud_clear(pud); | |
309 | } | |
310 | ||
311 | static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d) | |
312 | { | |
313 | pud_t *pud; | |
314 | int i; | |
315 | ||
316 | for (i = 0; i < PTRS_PER_PUD; i++) { | |
317 | pud = pud_start + i; | |
318 | if (!pud_none(*pud)) | |
319 | return; | |
320 | } | |
321 | ||
322 | pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d))); | |
323 | p4d_clear(p4d); | |
324 | } | |
325 | ||
326 | static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd) | |
327 | { | |
328 | p4d_t *p4d; | |
329 | int i; | |
330 | ||
331 | for (i = 0; i < PTRS_PER_P4D; i++) { | |
332 | p4d = p4d_start + i; | |
333 | if (!p4d_none(*p4d)) | |
334 | return; | |
335 | } | |
336 | ||
337 | p4d_free(&init_mm, (p4d_t *)page_to_virt(pgd_page(*pgd))); | |
338 | pgd_clear(pgd); | |
339 | } | |
340 | ||
341 | static void kasan_remove_pte_table(pte_t *pte, unsigned long addr, | |
342 | unsigned long end) | |
343 | { | |
344 | unsigned long next; | |
345 | ||
346 | for (; addr < end; addr = next, pte++) { | |
347 | next = (addr + PAGE_SIZE) & PAGE_MASK; | |
348 | if (next > end) | |
349 | next = end; | |
350 | ||
351 | if (!pte_present(*pte)) | |
352 | continue; | |
353 | ||
354 | if (WARN_ON(!kasan_zero_page_entry(*pte))) | |
355 | continue; | |
356 | pte_clear(&init_mm, addr, pte); | |
357 | } | |
358 | } | |
359 | ||
360 | static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr, | |
361 | unsigned long end) | |
362 | { | |
363 | unsigned long next; | |
364 | ||
365 | for (; addr < end; addr = next, pmd++) { | |
366 | pte_t *pte; | |
367 | ||
368 | next = pmd_addr_end(addr, end); | |
369 | ||
370 | if (!pmd_present(*pmd)) | |
371 | continue; | |
372 | ||
373 | if (kasan_pte_table(*pmd)) { | |
374 | if (IS_ALIGNED(addr, PMD_SIZE) && | |
375 | IS_ALIGNED(next, PMD_SIZE)) | |
376 | pmd_clear(pmd); | |
377 | continue; | |
378 | } | |
379 | pte = pte_offset_kernel(pmd, addr); | |
380 | kasan_remove_pte_table(pte, addr, next); | |
381 | kasan_free_pte(pte_offset_kernel(pmd, 0), pmd); | |
382 | } | |
383 | } | |
384 | ||
385 | static void kasan_remove_pud_table(pud_t *pud, unsigned long addr, | |
386 | unsigned long end) | |
387 | { | |
388 | unsigned long next; | |
389 | ||
390 | for (; addr < end; addr = next, pud++) { | |
391 | pmd_t *pmd, *pmd_base; | |
392 | ||
393 | next = pud_addr_end(addr, end); | |
394 | ||
395 | if (!pud_present(*pud)) | |
396 | continue; | |
397 | ||
398 | if (kasan_pmd_table(*pud)) { | |
399 | if (IS_ALIGNED(addr, PUD_SIZE) && | |
400 | IS_ALIGNED(next, PUD_SIZE)) | |
401 | pud_clear(pud); | |
402 | continue; | |
403 | } | |
404 | pmd = pmd_offset(pud, addr); | |
405 | pmd_base = pmd_offset(pud, 0); | |
406 | kasan_remove_pmd_table(pmd, addr, next); | |
407 | kasan_free_pmd(pmd_base, pud); | |
408 | } | |
409 | } | |
410 | ||
411 | static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr, | |
412 | unsigned long end) | |
413 | { | |
414 | unsigned long next; | |
415 | ||
416 | for (; addr < end; addr = next, p4d++) { | |
417 | pud_t *pud; | |
418 | ||
419 | next = p4d_addr_end(addr, end); | |
420 | ||
421 | if (!p4d_present(*p4d)) | |
422 | continue; | |
423 | ||
424 | if (kasan_pud_table(*p4d)) { | |
425 | if (IS_ALIGNED(addr, P4D_SIZE) && | |
426 | IS_ALIGNED(next, P4D_SIZE)) | |
427 | p4d_clear(p4d); | |
428 | continue; | |
429 | } | |
430 | pud = pud_offset(p4d, addr); | |
431 | kasan_remove_pud_table(pud, addr, next); | |
432 | kasan_free_pud(pud_offset(p4d, 0), p4d); | |
433 | } | |
434 | } | |
435 | ||
436 | void kasan_remove_zero_shadow(void *start, unsigned long size) | |
437 | { | |
438 | unsigned long addr, end, next; | |
439 | pgd_t *pgd; | |
440 | ||
441 | addr = (unsigned long)kasan_mem_to_shadow(start); | |
442 | end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT); | |
443 | ||
444 | if (WARN_ON((unsigned long)start % | |
445 | (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) || | |
446 | WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE))) | |
447 | return; | |
448 | ||
449 | for (; addr < end; addr = next) { | |
450 | p4d_t *p4d; | |
451 | ||
452 | next = pgd_addr_end(addr, end); | |
453 | ||
454 | pgd = pgd_offset_k(addr); | |
455 | if (!pgd_present(*pgd)) | |
456 | continue; | |
457 | ||
458 | if (kasan_p4d_table(*pgd)) { | |
459 | if (IS_ALIGNED(addr, PGDIR_SIZE) && | |
460 | IS_ALIGNED(next, PGDIR_SIZE)) | |
461 | pgd_clear(pgd); | |
462 | continue; | |
463 | } | |
464 | ||
465 | p4d = p4d_offset(pgd, addr); | |
466 | kasan_remove_p4d_table(p4d, addr, next); | |
467 | kasan_free_p4d(p4d_offset(pgd, 0), pgd); | |
468 | } | |
469 | } | |
470 | ||
471 | int kasan_add_zero_shadow(void *start, unsigned long size) | |
472 | { | |
473 | int ret; | |
474 | void *shadow_start, *shadow_end; | |
475 | ||
476 | shadow_start = kasan_mem_to_shadow(start); | |
477 | shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT); | |
478 | ||
479 | if (WARN_ON((unsigned long)start % | |
480 | (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) || | |
481 | WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE))) | |
482 | return -EINVAL; | |
483 | ||
484 | ret = kasan_populate_zero_shadow(shadow_start, shadow_end); | |
485 | if (ret) | |
486 | kasan_remove_zero_shadow(shadow_start, | |
487 | size >> KASAN_SHADOW_SCALE_SHIFT); | |
488 | return ret; | |
69786cdb | 489 | } |