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1// SPDX-License-Identifier: GPL-2.0
2// Copyright (C) 2019 Andes Technology Corporation
3
4#include <linux/pfn.h>
5#include <linux/init_task.h>
6#include <linux/kasan.h>
7#include <linux/kernel.h>
8#include <linux/memblock.h>
9#include <linux/pgtable.h>
10#include <asm/tlbflush.h>
11#include <asm/fixmap.h>
12#include <asm/pgalloc.h>
13
14/*
15 * Kasan shadow region must lie at a fixed address across sv39, sv48 and sv57
16 * which is right before the kernel.
17 *
18 * For sv39, the region is aligned on PGDIR_SIZE so we only need to populate
19 * the page global directory with kasan_early_shadow_pmd.
20 *
21 * For sv48 and sv57, the region is not aligned on PGDIR_SIZE so the mapping
22 * must be divided as follows:
23 * - the first PGD entry, although incomplete, is populated with
24 * kasan_early_shadow_pud/p4d
25 * - the PGD entries in the middle are populated with kasan_early_shadow_pud/p4d
26 * - the last PGD entry is shared with the kernel mapping so populated at the
27 * lower levels pud/p4d
28 *
29 * In addition, when shallow populating a kasan region (for example vmalloc),
30 * this region may also not be aligned on PGDIR size, so we must go down to the
31 * pud level too.
32 */
33
34extern pgd_t early_pg_dir[PTRS_PER_PGD];
35
36static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned long end)
37{
38 phys_addr_t phys_addr;
39 pte_t *ptep, *base_pte;
40
41 if (pmd_none(*pmd))
42 base_pte = memblock_alloc(PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE);
43 else
44 base_pte = (pte_t *)pmd_page_vaddr(*pmd);
45
46 ptep = base_pte + pte_index(vaddr);
47
48 do {
49 if (pte_none(*ptep)) {
50 phys_addr = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
51 set_pte(ptep, pfn_pte(PFN_DOWN(phys_addr), PAGE_KERNEL));
52 }
53 } while (ptep++, vaddr += PAGE_SIZE, vaddr != end);
54
55 set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(base_pte)), PAGE_TABLE));
56}
57
58static void __init kasan_populate_pmd(pud_t *pud, unsigned long vaddr, unsigned long end)
59{
60 phys_addr_t phys_addr;
61 pmd_t *pmdp, *base_pmd;
62 unsigned long next;
63
64 if (pud_none(*pud)) {
65 base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
66 } else {
67 base_pmd = (pmd_t *)pud_pgtable(*pud);
68 if (base_pmd == lm_alias(kasan_early_shadow_pmd))
69 base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
70 }
71
72 pmdp = base_pmd + pmd_index(vaddr);
73
74 do {
75 next = pmd_addr_end(vaddr, end);
76
77 if (pmd_none(*pmdp) && IS_ALIGNED(vaddr, PMD_SIZE) && (next - vaddr) >= PMD_SIZE) {
78 phys_addr = memblock_phys_alloc(PMD_SIZE, PMD_SIZE);
79 if (phys_addr) {
80 set_pmd(pmdp, pfn_pmd(PFN_DOWN(phys_addr), PAGE_KERNEL));
81 continue;
82 }
83 }
84
85 kasan_populate_pte(pmdp, vaddr, next);
86 } while (pmdp++, vaddr = next, vaddr != end);
87
88 /*
89 * Wait for the whole PGD to be populated before setting the PGD in
90 * the page table, otherwise, if we did set the PGD before populating
91 * it entirely, memblock could allocate a page at a physical address
92 * where KASAN is not populated yet and then we'd get a page fault.
93 */
94 set_pud(pud, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE));
95}
96
97static void __init kasan_populate_pud(pgd_t *pgd,
98 unsigned long vaddr, unsigned long end,
99 bool early)
100{
101 phys_addr_t phys_addr;
102 pud_t *pudp, *base_pud;
103 unsigned long next;
104
105 if (early) {
106 /*
107 * We can't use pgd_page_vaddr here as it would return a linear
108 * mapping address but it is not mapped yet, but when populating
109 * early_pg_dir, we need the physical address and when populating
110 * swapper_pg_dir, we need the kernel virtual address so use
111 * pt_ops facility.
112 */
113 base_pud = pt_ops.get_pud_virt(pfn_to_phys(_pgd_pfn(*pgd)));
114 } else if (pgd_none(*pgd)) {
115 base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
116 memcpy(base_pud, (void *)kasan_early_shadow_pud,
117 sizeof(pud_t) * PTRS_PER_PUD);
118 } else {
119 base_pud = (pud_t *)pgd_page_vaddr(*pgd);
120 if (base_pud == lm_alias(kasan_early_shadow_pud)) {
121 base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
122 memcpy(base_pud, (void *)kasan_early_shadow_pud,
123 sizeof(pud_t) * PTRS_PER_PUD);
124 }
125 }
126
127 pudp = base_pud + pud_index(vaddr);
128
129 do {
130 next = pud_addr_end(vaddr, end);
131
132 if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) {
133 if (early) {
134 phys_addr = __pa(((uintptr_t)kasan_early_shadow_pmd));
135 set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE));
136 continue;
137 } else {
138 phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE);
139 if (phys_addr) {
140 set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL));
141 continue;
142 }
143 }
144 }
145
146 kasan_populate_pmd(pudp, vaddr, next);
147 } while (pudp++, vaddr = next, vaddr != end);
148
149 /*
150 * Wait for the whole PGD to be populated before setting the PGD in
151 * the page table, otherwise, if we did set the PGD before populating
152 * it entirely, memblock could allocate a page at a physical address
153 * where KASAN is not populated yet and then we'd get a page fault.
154 */
155 if (!early)
156 set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pud)), PAGE_TABLE));
157}
158
159static void __init kasan_populate_p4d(pgd_t *pgd,
160 unsigned long vaddr, unsigned long end,
161 bool early)
162{
163 phys_addr_t phys_addr;
164 p4d_t *p4dp, *base_p4d;
165 unsigned long next;
166
167 if (early) {
168 /*
169 * We can't use pgd_page_vaddr here as it would return a linear
170 * mapping address but it is not mapped yet, but when populating
171 * early_pg_dir, we need the physical address and when populating
172 * swapper_pg_dir, we need the kernel virtual address so use
173 * pt_ops facility.
174 */
175 base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgd)));
176 } else {
177 base_p4d = (p4d_t *)pgd_page_vaddr(*pgd);
178 if (base_p4d == lm_alias(kasan_early_shadow_p4d)) {
179 base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE);
180 memcpy(base_p4d, (void *)kasan_early_shadow_p4d,
181 sizeof(p4d_t) * PTRS_PER_P4D);
182 }
183 }
184
185 p4dp = base_p4d + p4d_index(vaddr);
186
187 do {
188 next = p4d_addr_end(vaddr, end);
189
190 if (p4d_none(*p4dp) && IS_ALIGNED(vaddr, P4D_SIZE) && (next - vaddr) >= P4D_SIZE) {
191 if (early) {
192 phys_addr = __pa(((uintptr_t)kasan_early_shadow_pud));
193 set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_TABLE));
194 continue;
195 } else {
196 phys_addr = memblock_phys_alloc(P4D_SIZE, P4D_SIZE);
197 if (phys_addr) {
198 set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_KERNEL));
199 continue;
200 }
201 }
202 }
203
204 kasan_populate_pud((pgd_t *)p4dp, vaddr, next, early);
205 } while (p4dp++, vaddr = next, vaddr != end);
206
207 /*
208 * Wait for the whole P4D to be populated before setting the P4D in
209 * the page table, otherwise, if we did set the P4D before populating
210 * it entirely, memblock could allocate a page at a physical address
211 * where KASAN is not populated yet and then we'd get a page fault.
212 */
213 if (!early)
214 set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_p4d)), PAGE_TABLE));
215}
216
217#define kasan_early_shadow_pgd_next (pgtable_l5_enabled ? \
218 (uintptr_t)kasan_early_shadow_p4d : \
219 (pgtable_l4_enabled ? \
220 (uintptr_t)kasan_early_shadow_pud : \
221 (uintptr_t)kasan_early_shadow_pmd))
222#define kasan_populate_pgd_next(pgdp, vaddr, next, early) \
223 (pgtable_l5_enabled ? \
224 kasan_populate_p4d(pgdp, vaddr, next, early) : \
225 (pgtable_l4_enabled ? \
226 kasan_populate_pud(pgdp, vaddr, next, early) : \
227 kasan_populate_pmd((pud_t *)pgdp, vaddr, next)))
228
229static void __init kasan_populate_pgd(pgd_t *pgdp,
230 unsigned long vaddr, unsigned long end,
231 bool early)
232{
233 phys_addr_t phys_addr;
234 unsigned long next;
235
236 do {
237 next = pgd_addr_end(vaddr, end);
238
239 if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) {
240 if (early) {
241 phys_addr = __pa((uintptr_t)kasan_early_shadow_pgd_next);
242 set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE));
243 continue;
244 } else if (pgd_page_vaddr(*pgdp) ==
245 (unsigned long)lm_alias(kasan_early_shadow_pgd_next)) {
246 /*
247 * pgdp can't be none since kasan_early_init
248 * initialized all KASAN shadow region with
249 * kasan_early_shadow_pud: if this is still the
250 * case, that means we can try to allocate a
251 * hugepage as a replacement.
252 */
253 phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE);
254 if (phys_addr) {
255 set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_KERNEL));
256 continue;
257 }
258 }
259 }
260
261 kasan_populate_pgd_next(pgdp, vaddr, next, early);
262 } while (pgdp++, vaddr = next, vaddr != end);
263}
264
265asmlinkage void __init kasan_early_init(void)
266{
267 uintptr_t i;
268
269 BUILD_BUG_ON(KASAN_SHADOW_OFFSET !=
270 KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT)));
271
272 for (i = 0; i < PTRS_PER_PTE; ++i)
273 set_pte(kasan_early_shadow_pte + i,
274 pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL));
275
276 for (i = 0; i < PTRS_PER_PMD; ++i)
277 set_pmd(kasan_early_shadow_pmd + i,
278 pfn_pmd(PFN_DOWN
279 (__pa((uintptr_t)kasan_early_shadow_pte)),
280 PAGE_TABLE));
281
282 if (pgtable_l4_enabled) {
283 for (i = 0; i < PTRS_PER_PUD; ++i)
284 set_pud(kasan_early_shadow_pud + i,
285 pfn_pud(PFN_DOWN
286 (__pa(((uintptr_t)kasan_early_shadow_pmd))),
287 PAGE_TABLE));
288 }
289
290 if (pgtable_l5_enabled) {
291 for (i = 0; i < PTRS_PER_P4D; ++i)
292 set_p4d(kasan_early_shadow_p4d + i,
293 pfn_p4d(PFN_DOWN
294 (__pa(((uintptr_t)kasan_early_shadow_pud))),
295 PAGE_TABLE));
296 }
297
298 kasan_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START),
299 KASAN_SHADOW_START, KASAN_SHADOW_END, true);
300
301 local_flush_tlb_all();
302}
303
304void __init kasan_swapper_init(void)
305{
306 kasan_populate_pgd(pgd_offset_k(KASAN_SHADOW_START),
307 KASAN_SHADOW_START, KASAN_SHADOW_END, true);
308
309 local_flush_tlb_all();
310}
311
312static void __init kasan_populate(void *start, void *end)
313{
314 unsigned long vaddr = (unsigned long)start & PAGE_MASK;
315 unsigned long vend = PAGE_ALIGN((unsigned long)end);
316
317 kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend, false);
318
319 local_flush_tlb_all();
320 memset(start, KASAN_SHADOW_INIT, end - start);
321}
322
323static void __init kasan_shallow_populate_pmd(pgd_t *pgdp,
324 unsigned long vaddr, unsigned long end)
325{
326 unsigned long next;
327 pmd_t *pmdp, *base_pmd;
328 bool is_kasan_pte;
329
330 base_pmd = (pmd_t *)pgd_page_vaddr(*pgdp);
331 pmdp = base_pmd + pmd_index(vaddr);
332
333 do {
334 next = pmd_addr_end(vaddr, end);
335 is_kasan_pte = (pmd_pgtable(*pmdp) == lm_alias(kasan_early_shadow_pte));
336
337 if (is_kasan_pte)
338 pmd_clear(pmdp);
339 } while (pmdp++, vaddr = next, vaddr != end);
340}
341
342static void __init kasan_shallow_populate_pud(pgd_t *pgdp,
343 unsigned long vaddr, unsigned long end)
344{
345 unsigned long next;
346 pud_t *pudp, *base_pud;
347 pmd_t *base_pmd;
348 bool is_kasan_pmd;
349
350 base_pud = (pud_t *)pgd_page_vaddr(*pgdp);
351 pudp = base_pud + pud_index(vaddr);
352
353 do {
354 next = pud_addr_end(vaddr, end);
355 is_kasan_pmd = (pud_pgtable(*pudp) == lm_alias(kasan_early_shadow_pmd));
356
357 if (!is_kasan_pmd)
358 continue;
359
360 base_pmd = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
361 set_pud(pudp, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE));
362
363 if (IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE)
364 continue;
365
366 memcpy(base_pmd, (void *)kasan_early_shadow_pmd, PAGE_SIZE);
367 kasan_shallow_populate_pmd((pgd_t *)pudp, vaddr, next);
368 } while (pudp++, vaddr = next, vaddr != end);
369}
370
371static void __init kasan_shallow_populate_p4d(pgd_t *pgdp,
372 unsigned long vaddr, unsigned long end)
373{
374 unsigned long next;
375 p4d_t *p4dp, *base_p4d;
376 pud_t *base_pud;
377 bool is_kasan_pud;
378
379 base_p4d = (p4d_t *)pgd_page_vaddr(*pgdp);
380 p4dp = base_p4d + p4d_index(vaddr);
381
382 do {
383 next = p4d_addr_end(vaddr, end);
384 is_kasan_pud = (p4d_pgtable(*p4dp) == lm_alias(kasan_early_shadow_pud));
385
386 if (!is_kasan_pud)
387 continue;
388
389 base_pud = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
390 set_p4d(p4dp, pfn_p4d(PFN_DOWN(__pa(base_pud)), PAGE_TABLE));
391
392 if (IS_ALIGNED(vaddr, P4D_SIZE) && (next - vaddr) >= P4D_SIZE)
393 continue;
394
395 memcpy(base_pud, (void *)kasan_early_shadow_pud, PAGE_SIZE);
396 kasan_shallow_populate_pud((pgd_t *)p4dp, vaddr, next);
397 } while (p4dp++, vaddr = next, vaddr != end);
398}
399
400#define kasan_shallow_populate_pgd_next(pgdp, vaddr, next) \
401 (pgtable_l5_enabled ? \
402 kasan_shallow_populate_p4d(pgdp, vaddr, next) : \
403 (pgtable_l4_enabled ? \
404 kasan_shallow_populate_pud(pgdp, vaddr, next) : \
405 kasan_shallow_populate_pmd(pgdp, vaddr, next)))
406
407static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end)
408{
409 unsigned long next;
410 void *p;
411 pgd_t *pgd_k = pgd_offset_k(vaddr);
412 bool is_kasan_pgd_next;
413
414 do {
415 next = pgd_addr_end(vaddr, end);
416 is_kasan_pgd_next = (pgd_page_vaddr(*pgd_k) ==
417 (unsigned long)lm_alias(kasan_early_shadow_pgd_next));
418
419 if (is_kasan_pgd_next) {
420 p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
421 set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
422 }
423
424 if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE)
425 continue;
426
427 memcpy(p, (void *)kasan_early_shadow_pgd_next, PAGE_SIZE);
428 kasan_shallow_populate_pgd_next(pgd_k, vaddr, next);
429 } while (pgd_k++, vaddr = next, vaddr != end);
430}
431
432static void __init kasan_shallow_populate(void *start, void *end)
433{
434 unsigned long vaddr = (unsigned long)start & PAGE_MASK;
435 unsigned long vend = PAGE_ALIGN((unsigned long)end);
436
437 kasan_shallow_populate_pgd(vaddr, vend);
438 local_flush_tlb_all();
439}
440
441void __init kasan_init(void)
442{
443 phys_addr_t p_start, p_end;
444 u64 i;
445
446 if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
447 kasan_shallow_populate(
448 (void *)kasan_mem_to_shadow((void *)VMALLOC_START),
449 (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
450
451 /* Populate the linear mapping */
452 for_each_mem_range(i, &p_start, &p_end) {
453 void *start = (void *)__va(p_start);
454 void *end = (void *)__va(p_end);
455
456 if (start >= end)
457 break;
458
459 kasan_populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end));
460 }
461
462 /* Populate kernel, BPF, modules mapping */
463 kasan_populate(kasan_mem_to_shadow((const void *)MODULES_VADDR),
464 kasan_mem_to_shadow((const void *)MODULES_VADDR + SZ_2G));
465
466 for (i = 0; i < PTRS_PER_PTE; i++)
467 set_pte(&kasan_early_shadow_pte[i],
468 mk_pte(virt_to_page(kasan_early_shadow_page),
469 __pgprot(_PAGE_PRESENT | _PAGE_READ |
470 _PAGE_ACCESSED)));
471
472 memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
473 init_task.kasan_depth = 0;
474}