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1// SPDX-License-Identifier: GPL-2.0
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
14#include <linux/memblock.h>
15#include <linux/init.h>
16#include <linux/kasan.h>
17#include <linux/kernel.h>
18#include <linux/mm.h>
19#include <linux/pfn.h>
20#include <linux/slab.h>
21
22#include <asm/page.h>
23#include <asm/pgalloc.h>
24
25#include "kasan.h"
26
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 */
34unsigned char kasan_early_shadow_page[PAGE_SIZE] __page_aligned_bss;
35
36#if CONFIG_PGTABLE_LEVELS > 4
37p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss;
38static inline bool kasan_p4d_table(pgd_t pgd)
39{
40 return pgd_page(pgd) == virt_to_page(lm_alias(kasan_early_shadow_p4d));
41}
42#else
43static inline bool kasan_p4d_table(pgd_t pgd)
44{
45 return false;
46}
47#endif
48#if CONFIG_PGTABLE_LEVELS > 3
49pud_t kasan_early_shadow_pud[PTRS_PER_PUD] __page_aligned_bss;
50static inline bool kasan_pud_table(p4d_t p4d)
51{
52 return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud));
53}
54#else
55static inline bool kasan_pud_table(p4d_t p4d)
56{
57 return false;
58}
59#endif
60#if CONFIG_PGTABLE_LEVELS > 2
61pmd_t kasan_early_shadow_pmd[PTRS_PER_PMD] __page_aligned_bss;
62static inline bool kasan_pmd_table(pud_t pud)
63{
64 return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd));
65}
66#else
67static inline bool kasan_pmd_table(pud_t pud)
68{
69 return false;
70}
71#endif
72pte_t kasan_early_shadow_pte[PTRS_PER_PTE] __page_aligned_bss;
73
74static inline bool kasan_pte_table(pmd_t pmd)
75{
76 return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte));
77}
78
79static inline bool kasan_early_shadow_page_entry(pte_t pte)
80{
81 return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page));
82}
83
84static __init void *early_alloc(size_t size, int node)
85{
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;
94}
95
96static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr,
97 unsigned long end)
98{
99 pte_t *pte = pte_offset_kernel(pmd, addr);
100 pte_t zero_pte;
101
102 zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)),
103 PAGE_KERNEL);
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
113static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr,
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) {
123 pmd_populate_kernel(&init_mm, pmd,
124 lm_alias(kasan_early_shadow_pte));
125 continue;
126 }
127
128 if (pmd_none(*pmd)) {
129 pte_t *p;
130
131 if (slab_is_available())
132 p = pte_alloc_one_kernel(&init_mm);
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);
139 }
140 zero_pte_populate(pmd, addr, next);
141 } while (pmd++, addr = next, addr != end);
142
143 return 0;
144}
145
146static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
147 unsigned long end)
148{
149 pud_t *pud = pud_offset(p4d, addr);
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
157 pud_populate(&init_mm, pud,
158 lm_alias(kasan_early_shadow_pmd));
159 pmd = pmd_offset(pud, addr);
160 pmd_populate_kernel(&init_mm, pmd,
161 lm_alias(kasan_early_shadow_pte));
162 continue;
163 }
164
165 if (pud_none(*pud)) {
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 }
176 }
177 zero_pmd_populate(pud, addr, next);
178 } while (pud++, addr = next, addr != end);
179
180 return 0;
181}
182
183static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
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);
191 if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
192 pud_t *pud;
193 pmd_t *pmd;
194
195 p4d_populate(&init_mm, p4d,
196 lm_alias(kasan_early_shadow_pud));
197 pud = pud_offset(p4d, addr);
198 pud_populate(&init_mm, pud,
199 lm_alias(kasan_early_shadow_pmd));
200 pmd = pmd_offset(pud, addr);
201 pmd_populate_kernel(&init_mm, pmd,
202 lm_alias(kasan_early_shadow_pte));
203 continue;
204 }
205
206 if (p4d_none(*p4d)) {
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 }
217 }
218 zero_pud_populate(p4d, addr, next);
219 } while (p4d++, addr = next, addr != end);
220
221 return 0;
222}
223
224/**
225 * kasan_populate_early_shadow - populate shadow memory region with
226 * kasan_early_shadow_page
227 * @shadow_start - start of the memory range to populate
228 * @shadow_end - end of the memory range to populate
229 */
230int __ref kasan_populate_early_shadow(const void *shadow_start,
231 const void *shadow_end)
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) {
242 p4d_t *p4d;
243 pud_t *pud;
244 pmd_t *pmd;
245
246 /*
247 * kasan_early_shadow_pud should be populated with pmds
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.
253 *
254 * The ifndef is required to avoid build breakage.
255 *
256 * With 5level-fixup.h, pgd_populate() is not nop and
257 * we reference kasan_early_shadow_p4d. It's not defined
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.
262 */
263#ifndef __ARCH_HAS_5LEVEL_HACK
264 pgd_populate(&init_mm, pgd,
265 lm_alias(kasan_early_shadow_p4d));
266#endif
267 p4d = p4d_offset(pgd, addr);
268 p4d_populate(&init_mm, p4d,
269 lm_alias(kasan_early_shadow_pud));
270 pud = pud_offset(p4d, addr);
271 pud_populate(&init_mm, pud,
272 lm_alias(kasan_early_shadow_pmd));
273 pmd = pmd_offset(pud, addr);
274 pmd_populate_kernel(&init_mm, pmd,
275 lm_alias(kasan_early_shadow_pte));
276 continue;
277 }
278
279 if (pgd_none(*pgd)) {
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 }
290 }
291 zero_p4d_populate(pgd, addr, next);
292 } while (pgd++, addr = next, addr != end);
293
294 return 0;
295}
296
297static 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
312static 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
327static 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
342static 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
357static 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
370 if (WARN_ON(!kasan_early_shadow_page_entry(*pte)))
371 continue;
372 pte_clear(&init_mm, addr, pte);
373 }
374}
375
376static 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
401static 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
427static 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
452void 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
487int 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
500 ret = kasan_populate_early_shadow(shadow_start, shadow_end);
501 if (ret)
502 kasan_remove_zero_shadow(shadow_start,
503 size >> KASAN_SHADOW_SCALE_SHIFT);
504 return ret;
505}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * This file contains KASAN shadow initialization code.
4 *
5 * Copyright (c) 2015 Samsung Electronics Co., Ltd.
6 * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
7 */
8
9#include <linux/memblock.h>
10#include <linux/init.h>
11#include <linux/kasan.h>
12#include <linux/kernel.h>
13#include <linux/mm.h>
14#include <linux/pfn.h>
15#include <linux/slab.h>
16
17#include <asm/page.h>
18#include <asm/pgalloc.h>
19
20#include "kasan.h"
21
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 */
29unsigned char kasan_early_shadow_page[PAGE_SIZE] __page_aligned_bss;
30
31#if CONFIG_PGTABLE_LEVELS > 4
32p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss;
33static inline bool kasan_p4d_table(pgd_t pgd)
34{
35 return pgd_page(pgd) == virt_to_page(lm_alias(kasan_early_shadow_p4d));
36}
37#else
38static inline bool kasan_p4d_table(pgd_t pgd)
39{
40 return false;
41}
42#endif
43#if CONFIG_PGTABLE_LEVELS > 3
44pud_t kasan_early_shadow_pud[MAX_PTRS_PER_PUD] __page_aligned_bss;
45static inline bool kasan_pud_table(p4d_t p4d)
46{
47 return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud));
48}
49#else
50static inline bool kasan_pud_table(p4d_t p4d)
51{
52 return false;
53}
54#endif
55#if CONFIG_PGTABLE_LEVELS > 2
56pmd_t kasan_early_shadow_pmd[MAX_PTRS_PER_PMD] __page_aligned_bss;
57static inline bool kasan_pmd_table(pud_t pud)
58{
59 return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd));
60}
61#else
62static inline bool kasan_pmd_table(pud_t pud)
63{
64 return false;
65}
66#endif
67pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS]
68 __page_aligned_bss;
69
70static inline bool kasan_pte_table(pmd_t pmd)
71{
72 return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte));
73}
74
75static inline bool kasan_early_shadow_page_entry(pte_t pte)
76{
77 return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page));
78}
79
80static __init void *early_alloc(size_t size, int node)
81{
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;
90}
91
92static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr,
93 unsigned long end)
94{
95 pte_t *pte = pte_offset_kernel(pmd, addr);
96 pte_t zero_pte;
97
98 zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)),
99 PAGE_KERNEL);
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
109static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr,
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) {
119 pmd_populate_kernel(&init_mm, pmd,
120 lm_alias(kasan_early_shadow_pte));
121 continue;
122 }
123
124 if (pmd_none(*pmd)) {
125 pte_t *p;
126
127 if (slab_is_available())
128 p = pte_alloc_one_kernel(&init_mm);
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);
135 }
136 zero_pte_populate(pmd, addr, next);
137 } while (pmd++, addr = next, addr != end);
138
139 return 0;
140}
141
142static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
143 unsigned long end)
144{
145 pud_t *pud = pud_offset(p4d, addr);
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
153 pud_populate(&init_mm, pud,
154 lm_alias(kasan_early_shadow_pmd));
155 pmd = pmd_offset(pud, addr);
156 pmd_populate_kernel(&init_mm, pmd,
157 lm_alias(kasan_early_shadow_pte));
158 continue;
159 }
160
161 if (pud_none(*pud)) {
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 }
172 }
173 zero_pmd_populate(pud, addr, next);
174 } while (pud++, addr = next, addr != end);
175
176 return 0;
177}
178
179static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
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);
187 if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
188 pud_t *pud;
189 pmd_t *pmd;
190
191 p4d_populate(&init_mm, p4d,
192 lm_alias(kasan_early_shadow_pud));
193 pud = pud_offset(p4d, addr);
194 pud_populate(&init_mm, pud,
195 lm_alias(kasan_early_shadow_pmd));
196 pmd = pmd_offset(pud, addr);
197 pmd_populate_kernel(&init_mm, pmd,
198 lm_alias(kasan_early_shadow_pte));
199 continue;
200 }
201
202 if (p4d_none(*p4d)) {
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 }
213 }
214 zero_pud_populate(p4d, addr, next);
215 } while (p4d++, addr = next, addr != end);
216
217 return 0;
218}
219
220/**
221 * kasan_populate_early_shadow - populate shadow memory region with
222 * kasan_early_shadow_page
223 * @shadow_start: start of the memory range to populate
224 * @shadow_end: end of the memory range to populate
225 */
226int __ref kasan_populate_early_shadow(const void *shadow_start,
227 const void *shadow_end)
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) {
238 p4d_t *p4d;
239 pud_t *pud;
240 pmd_t *pmd;
241
242 /*
243 * kasan_early_shadow_pud should be populated with pmds
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 */
250 pgd_populate(&init_mm, pgd,
251 lm_alias(kasan_early_shadow_p4d));
252 p4d = p4d_offset(pgd, addr);
253 p4d_populate(&init_mm, p4d,
254 lm_alias(kasan_early_shadow_pud));
255 pud = pud_offset(p4d, addr);
256 pud_populate(&init_mm, pud,
257 lm_alias(kasan_early_shadow_pmd));
258 pmd = pmd_offset(pud, addr);
259 pmd_populate_kernel(&init_mm, pmd,
260 lm_alias(kasan_early_shadow_pte));
261 continue;
262 }
263
264 if (pgd_none(*pgd)) {
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 }
275 }
276 zero_p4d_populate(pgd, addr, next);
277 } while (pgd++, addr = next, addr != end);
278
279 return 0;
280}
281
282static 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
297static 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
312static 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
327static 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
342static 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
355 if (WARN_ON(!kasan_early_shadow_page_entry(*pte)))
356 continue;
357 pte_clear(&init_mm, addr, pte);
358 }
359}
360
361static 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) &&
376 IS_ALIGNED(next, PMD_SIZE)) {
377 pmd_clear(pmd);
378 continue;
379 }
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
387static 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) &&
402 IS_ALIGNED(next, PUD_SIZE)) {
403 pud_clear(pud);
404 continue;
405 }
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
414static 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) &&
429 IS_ALIGNED(next, P4D_SIZE)) {
430 p4d_clear(p4d);
431 continue;
432 }
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
440void 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
448 if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||
449 WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
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) &&
463 IS_ALIGNED(next, PGDIR_SIZE)) {
464 pgd_clear(pgd);
465 continue;
466 }
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
475int 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
483 if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||
484 WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
485 return -EINVAL;
486
487 ret = kasan_populate_early_shadow(shadow_start, shadow_end);
488 if (ret)
489 kasan_remove_zero_shadow(start, size);
490 return ret;
491}