1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Based on arch/arm/mm/mmu.c
4 *
5 * Copyright (C) 1995-2005 Russell King
6 * Copyright (C) 2012 ARM Ltd.
7 */
8
9 #include <linux/cache.h>
10 #include <linux/export.h>
11 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/init.h>
14 #include <linux/ioport.h>
15 #include <linux/kexec.h>
16 #include <linux/libfdt.h>
17 #include <linux/mman.h>
18 #include <linux/nodemask.h>
19 #include <linux/memblock.h>
20 #include <linux/memremap.h>
21 #include <linux/memory.h>
22 #include <linux/fs.h>
23 #include <linux/io.h>
24 #include <linux/mm.h>
25 #include <linux/vmalloc.h>
26 #include <linux/set_memory.h>
27
28 #include <asm/barrier.h>
29 #include <asm/cputype.h>
30 #include <asm/fixmap.h>
31 #include <asm/kasan.h>
32 #include <asm/kernel-pgtable.h>
33 #include <asm/sections.h>
34 #include <asm/setup.h>
35 #include <linux/sizes.h>
36 #include <asm/tlb.h>
37 #include <asm/mmu_context.h>
38 #include <asm/ptdump.h>
39 #include <asm/tlbflush.h>
40 #include <asm/pgalloc.h>
41
42 #define NO_BLOCK_MAPPINGS BIT(0)
43 #define NO_CONT_MAPPINGS BIT(1)
44 #define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */
45
46 int idmap_t0sz __ro_after_init;
47
48 #if VA_BITS > 48
49 u64 vabits_actual __ro_after_init = VA_BITS_MIN;
50 EXPORT_SYMBOL(vabits_actual);
51 #endif
52
53 u64 kimage_vaddr __ro_after_init = (u64)&_text;
54 EXPORT_SYMBOL(kimage_vaddr);
55
56 u64 kimage_voffset __ro_after_init;
57 EXPORT_SYMBOL(kimage_voffset);
58
59 u32 __boot_cpu_mode[] = { BOOT_CPU_MODE_EL2, BOOT_CPU_MODE_EL1 };
60
61 /*
62 * The booting CPU updates the failed status @__early_cpu_boot_status,
63 * with MMU turned off.
64 */
65 long __section(".mmuoff.data.write") __early_cpu_boot_status;
66
67 /*
68 * Empty_zero_page is a special page that is used for zero-initialized data
69 * and COW.
70 */
71 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
72 EXPORT_SYMBOL(empty_zero_page);
73
74 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
75 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
76 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
77
78 static DEFINE_SPINLOCK(swapper_pgdir_lock);
79 static DEFINE_MUTEX(fixmap_lock);
80
set_swapper_pgd(pgd_t * pgdp,pgd_t pgd)81 void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd)
82 {
83 pgd_t *fixmap_pgdp;
84
85 spin_lock(&swapper_pgdir_lock);
86 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp));
87 WRITE_ONCE(*fixmap_pgdp, pgd);
88 /*
89 * We need dsb(ishst) here to ensure the page-table-walker sees
90 * our new entry before set_p?d() returns. The fixmap's
91 * flush_tlb_kernel_range() via clear_fixmap() does this for us.
92 */
93 pgd_clear_fixmap();
94 spin_unlock(&swapper_pgdir_lock);
95 }
96
phys_mem_access_prot(struct file * file,unsigned long pfn,unsigned long size,pgprot_t vma_prot)97 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
98 unsigned long size, pgprot_t vma_prot)
99 {
100 if (!pfn_is_map_memory(pfn))
101 return pgprot_noncached(vma_prot);
102 else if (file->f_flags & O_SYNC)
103 return pgprot_writecombine(vma_prot);
104 return vma_prot;
105 }
106 EXPORT_SYMBOL(phys_mem_access_prot);
107
early_pgtable_alloc(int shift)108 static phys_addr_t __init early_pgtable_alloc(int shift)
109 {
110 phys_addr_t phys;
111 void *ptr;
112
113 phys = memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE, 0,
114 MEMBLOCK_ALLOC_NOLEAKTRACE);
115 if (!phys)
116 panic("Failed to allocate page table page\n");
117
118 /*
119 * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
120 * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
121 * any level of table.
122 */
123 ptr = pte_set_fixmap(phys);
124
125 memset(ptr, 0, PAGE_SIZE);
126
127 /*
128 * Implicit barriers also ensure the zeroed page is visible to the page
129 * table walker
130 */
131 pte_clear_fixmap();
132
133 return phys;
134 }
135
pgattr_change_is_safe(u64 old,u64 new)136 static bool pgattr_change_is_safe(u64 old, u64 new)
137 {
138 /*
139 * The following mapping attributes may be updated in live
140 * kernel mappings without the need for break-before-make.
141 */
142 pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG;
143
144 /* creating or taking down mappings is always safe */
145 if (old == 0 || new == 0)
146 return true;
147
148 /* live contiguous mappings may not be manipulated at all */
149 if ((old | new) & PTE_CONT)
150 return false;
151
152 /* Transitioning from Non-Global to Global is unsafe */
153 if (old & ~new & PTE_NG)
154 return false;
155
156 /*
157 * Changing the memory type between Normal and Normal-Tagged is safe
158 * since Tagged is considered a permission attribute from the
159 * mismatched attribute aliases perspective.
160 */
161 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) ||
162 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) &&
163 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) ||
164 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)))
165 mask |= PTE_ATTRINDX_MASK;
166
167 return ((old ^ new) & ~mask) == 0;
168 }
169
init_pte(pmd_t * pmdp,unsigned long addr,unsigned long end,phys_addr_t phys,pgprot_t prot)170 static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
171 phys_addr_t phys, pgprot_t prot)
172 {
173 pte_t *ptep;
174
175 ptep = pte_set_fixmap_offset(pmdp, addr);
176 do {
177 pte_t old_pte = READ_ONCE(*ptep);
178
179 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot));
180
181 /*
182 * After the PTE entry has been populated once, we
183 * only allow updates to the permission attributes.
184 */
185 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte),
186 READ_ONCE(pte_val(*ptep))));
187
188 phys += PAGE_SIZE;
189 } while (ptep++, addr += PAGE_SIZE, addr != end);
190
191 pte_clear_fixmap();
192 }
193
alloc_init_cont_pte(pmd_t * pmdp,unsigned long addr,unsigned long end,phys_addr_t phys,pgprot_t prot,phys_addr_t (* pgtable_alloc)(int),int flags)194 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr,
195 unsigned long end, phys_addr_t phys,
196 pgprot_t prot,
197 phys_addr_t (*pgtable_alloc)(int),
198 int flags)
199 {
200 unsigned long next;
201 pmd_t pmd = READ_ONCE(*pmdp);
202
203 BUG_ON(pmd_sect(pmd));
204 if (pmd_none(pmd)) {
205 pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN;
206 phys_addr_t pte_phys;
207
208 if (flags & NO_EXEC_MAPPINGS)
209 pmdval |= PMD_TABLE_PXN;
210 BUG_ON(!pgtable_alloc);
211 pte_phys = pgtable_alloc(PAGE_SHIFT);
212 __pmd_populate(pmdp, pte_phys, pmdval);
213 pmd = READ_ONCE(*pmdp);
214 }
215 BUG_ON(pmd_bad(pmd));
216
217 do {
218 pgprot_t __prot = prot;
219
220 next = pte_cont_addr_end(addr, end);
221
222 /* use a contiguous mapping if the range is suitably aligned */
223 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) &&
224 (flags & NO_CONT_MAPPINGS) == 0)
225 __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
226
227 init_pte(pmdp, addr, next, phys, __prot);
228
229 phys += next - addr;
230 } while (addr = next, addr != end);
231 }
232
init_pmd(pud_t * pudp,unsigned long addr,unsigned long end,phys_addr_t phys,pgprot_t prot,phys_addr_t (* pgtable_alloc)(int),int flags)233 static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end,
234 phys_addr_t phys, pgprot_t prot,
235 phys_addr_t (*pgtable_alloc)(int), int flags)
236 {
237 unsigned long next;
238 pmd_t *pmdp;
239
240 pmdp = pmd_set_fixmap_offset(pudp, addr);
241 do {
242 pmd_t old_pmd = READ_ONCE(*pmdp);
243
244 next = pmd_addr_end(addr, end);
245
246 /* try section mapping first */
247 if (((addr | next | phys) & ~PMD_MASK) == 0 &&
248 (flags & NO_BLOCK_MAPPINGS) == 0) {
249 pmd_set_huge(pmdp, phys, prot);
250
251 /*
252 * After the PMD entry has been populated once, we
253 * only allow updates to the permission attributes.
254 */
255 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd),
256 READ_ONCE(pmd_val(*pmdp))));
257 } else {
258 alloc_init_cont_pte(pmdp, addr, next, phys, prot,
259 pgtable_alloc, flags);
260
261 BUG_ON(pmd_val(old_pmd) != 0 &&
262 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp)));
263 }
264 phys += next - addr;
265 } while (pmdp++, addr = next, addr != end);
266
267 pmd_clear_fixmap();
268 }
269
alloc_init_cont_pmd(pud_t * pudp,unsigned long addr,unsigned long end,phys_addr_t phys,pgprot_t prot,phys_addr_t (* pgtable_alloc)(int),int flags)270 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr,
271 unsigned long end, phys_addr_t phys,
272 pgprot_t prot,
273 phys_addr_t (*pgtable_alloc)(int), int flags)
274 {
275 unsigned long next;
276 pud_t pud = READ_ONCE(*pudp);
277
278 /*
279 * Check for initial section mappings in the pgd/pud.
280 */
281 BUG_ON(pud_sect(pud));
282 if (pud_none(pud)) {
283 pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN;
284 phys_addr_t pmd_phys;
285
286 if (flags & NO_EXEC_MAPPINGS)
287 pudval |= PUD_TABLE_PXN;
288 BUG_ON(!pgtable_alloc);
289 pmd_phys = pgtable_alloc(PMD_SHIFT);
290 __pud_populate(pudp, pmd_phys, pudval);
291 pud = READ_ONCE(*pudp);
292 }
293 BUG_ON(pud_bad(pud));
294
295 do {
296 pgprot_t __prot = prot;
297
298 next = pmd_cont_addr_end(addr, end);
299
300 /* use a contiguous mapping if the range is suitably aligned */
301 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) &&
302 (flags & NO_CONT_MAPPINGS) == 0)
303 __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
304
305 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags);
306
307 phys += next - addr;
308 } while (addr = next, addr != end);
309 }
310
alloc_init_pud(pgd_t * pgdp,unsigned long addr,unsigned long end,phys_addr_t phys,pgprot_t prot,phys_addr_t (* pgtable_alloc)(int),int flags)311 static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end,
312 phys_addr_t phys, pgprot_t prot,
313 phys_addr_t (*pgtable_alloc)(int),
314 int flags)
315 {
316 unsigned long next;
317 pud_t *pudp;
318 p4d_t *p4dp = p4d_offset(pgdp, addr);
319 p4d_t p4d = READ_ONCE(*p4dp);
320
321 if (p4d_none(p4d)) {
322 p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN;
323 phys_addr_t pud_phys;
324
325 if (flags & NO_EXEC_MAPPINGS)
326 p4dval |= P4D_TABLE_PXN;
327 BUG_ON(!pgtable_alloc);
328 pud_phys = pgtable_alloc(PUD_SHIFT);
329 __p4d_populate(p4dp, pud_phys, p4dval);
330 p4d = READ_ONCE(*p4dp);
331 }
332 BUG_ON(p4d_bad(p4d));
333
334 pudp = pud_set_fixmap_offset(p4dp, addr);
335 do {
336 pud_t old_pud = READ_ONCE(*pudp);
337
338 next = pud_addr_end(addr, end);
339
340 /*
341 * For 4K granule only, attempt to put down a 1GB block
342 */
343 if (pud_sect_supported() &&
344 ((addr | next | phys) & ~PUD_MASK) == 0 &&
345 (flags & NO_BLOCK_MAPPINGS) == 0) {
346 pud_set_huge(pudp, phys, prot);
347
348 /*
349 * After the PUD entry has been populated once, we
350 * only allow updates to the permission attributes.
351 */
352 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud),
353 READ_ONCE(pud_val(*pudp))));
354 } else {
355 alloc_init_cont_pmd(pudp, addr, next, phys, prot,
356 pgtable_alloc, flags);
357
358 BUG_ON(pud_val(old_pud) != 0 &&
359 pud_val(old_pud) != READ_ONCE(pud_val(*pudp)));
360 }
361 phys += next - addr;
362 } while (pudp++, addr = next, addr != end);
363
364 pud_clear_fixmap();
365 }
366
__create_pgd_mapping_locked(pgd_t * pgdir,phys_addr_t phys,unsigned long virt,phys_addr_t size,pgprot_t prot,phys_addr_t (* pgtable_alloc)(int),int flags)367 static void __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys,
368 unsigned long virt, phys_addr_t size,
369 pgprot_t prot,
370 phys_addr_t (*pgtable_alloc)(int),
371 int flags)
372 {
373 unsigned long addr, end, next;
374 pgd_t *pgdp = pgd_offset_pgd(pgdir, virt);
375
376 /*
377 * If the virtual and physical address don't have the same offset
378 * within a page, we cannot map the region as the caller expects.
379 */
380 if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
381 return;
382
383 phys &= PAGE_MASK;
384 addr = virt & PAGE_MASK;
385 end = PAGE_ALIGN(virt + size);
386
387 do {
388 next = pgd_addr_end(addr, end);
389 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc,
390 flags);
391 phys += next - addr;
392 } while (pgdp++, addr = next, addr != end);
393 }
394
__create_pgd_mapping(pgd_t * pgdir,phys_addr_t phys,unsigned long virt,phys_addr_t size,pgprot_t prot,phys_addr_t (* pgtable_alloc)(int),int flags)395 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
396 unsigned long virt, phys_addr_t size,
397 pgprot_t prot,
398 phys_addr_t (*pgtable_alloc)(int),
399 int flags)
400 {
401 mutex_lock(&fixmap_lock);
402 __create_pgd_mapping_locked(pgdir, phys, virt, size, prot,
403 pgtable_alloc, flags);
404 mutex_unlock(&fixmap_lock);
405 }
406
407 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
408 extern __alias(__create_pgd_mapping_locked)
409 void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt,
410 phys_addr_t size, pgprot_t prot,
411 phys_addr_t (*pgtable_alloc)(int), int flags);
412 #endif
413
__pgd_pgtable_alloc(int shift)414 static phys_addr_t __pgd_pgtable_alloc(int shift)
415 {
416 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL);
417 BUG_ON(!ptr);
418
419 /* Ensure the zeroed page is visible to the page table walker */
420 dsb(ishst);
421 return __pa(ptr);
422 }
423
pgd_pgtable_alloc(int shift)424 static phys_addr_t pgd_pgtable_alloc(int shift)
425 {
426 phys_addr_t pa = __pgd_pgtable_alloc(shift);
427
428 /*
429 * Call proper page table ctor in case later we need to
430 * call core mm functions like apply_to_page_range() on
431 * this pre-allocated page table.
432 *
433 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is
434 * folded, and if so pgtable_pmd_page_ctor() becomes nop.
435 */
436 if (shift == PAGE_SHIFT)
437 BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa)));
438 else if (shift == PMD_SHIFT)
439 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa)));
440
441 return pa;
442 }
443
444 /*
445 * This function can only be used to modify existing table entries,
446 * without allocating new levels of table. Note that this permits the
447 * creation of new section or page entries.
448 */
create_mapping_noalloc(phys_addr_t phys,unsigned long virt,phys_addr_t size,pgprot_t prot)449 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
450 phys_addr_t size, pgprot_t prot)
451 {
452 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) {
453 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
454 &phys, virt);
455 return;
456 }
457 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
458 NO_CONT_MAPPINGS);
459 }
460
create_pgd_mapping(struct mm_struct * mm,phys_addr_t phys,unsigned long virt,phys_addr_t size,pgprot_t prot,bool page_mappings_only)461 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
462 unsigned long virt, phys_addr_t size,
463 pgprot_t prot, bool page_mappings_only)
464 {
465 int flags = 0;
466
467 BUG_ON(mm == &init_mm);
468
469 if (page_mappings_only)
470 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
471
472 __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
473 pgd_pgtable_alloc, flags);
474 }
475
update_mapping_prot(phys_addr_t phys,unsigned long virt,phys_addr_t size,pgprot_t prot)476 static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
477 phys_addr_t size, pgprot_t prot)
478 {
479 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) {
480 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n",
481 &phys, virt);
482 return;
483 }
484
485 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
486 NO_CONT_MAPPINGS);
487
488 /* flush the TLBs after updating live kernel mappings */
489 flush_tlb_kernel_range(virt, virt + size);
490 }
491
__map_memblock(pgd_t * pgdp,phys_addr_t start,phys_addr_t end,pgprot_t prot,int flags)492 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start,
493 phys_addr_t end, pgprot_t prot, int flags)
494 {
495 __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start,
496 prot, early_pgtable_alloc, flags);
497 }
498
mark_linear_text_alias_ro(void)499 void __init mark_linear_text_alias_ro(void)
500 {
501 /*
502 * Remove the write permissions from the linear alias of .text/.rodata
503 */
504 update_mapping_prot(__pa_symbol(_stext), (unsigned long)lm_alias(_stext),
505 (unsigned long)__init_begin - (unsigned long)_stext,
506 PAGE_KERNEL_RO);
507 }
508
509 static bool crash_mem_map __initdata;
510
enable_crash_mem_map(char * arg)511 static int __init enable_crash_mem_map(char *arg)
512 {
513 /*
514 * Proper parameter parsing is done by reserve_crashkernel(). We only
515 * need to know if the linear map has to avoid block mappings so that
516 * the crashkernel reservations can be unmapped later.
517 */
518 crash_mem_map = true;
519
520 return 0;
521 }
522 early_param("crashkernel", enable_crash_mem_map);
523
map_mem(pgd_t * pgdp)524 static void __init map_mem(pgd_t *pgdp)
525 {
526 static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN);
527 phys_addr_t kernel_start = __pa_symbol(_stext);
528 phys_addr_t kernel_end = __pa_symbol(__init_begin);
529 phys_addr_t start, end;
530 int flags = NO_EXEC_MAPPINGS;
531 u64 i;
532
533 /*
534 * Setting hierarchical PXNTable attributes on table entries covering
535 * the linear region is only possible if it is guaranteed that no table
536 * entries at any level are being shared between the linear region and
537 * the vmalloc region. Check whether this is true for the PGD level, in
538 * which case it is guaranteed to be true for all other levels as well.
539 */
540 BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end));
541
542 if (can_set_direct_map())
543 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
544
545 /*
546 * Take care not to create a writable alias for the
547 * read-only text and rodata sections of the kernel image.
548 * So temporarily mark them as NOMAP to skip mappings in
549 * the following for-loop
550 */
551 memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
552
553 #ifdef CONFIG_KEXEC_CORE
554 if (crash_mem_map) {
555 if (defer_reserve_crashkernel())
556 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
557 else if (crashk_res.end)
558 memblock_mark_nomap(crashk_res.start,
559 resource_size(&crashk_res));
560 }
561 #endif
562
563 /* map all the memory banks */
564 for_each_mem_range(i, &start, &end) {
565 if (start >= end)
566 break;
567 /*
568 * The linear map must allow allocation tags reading/writing
569 * if MTE is present. Otherwise, it has the same attributes as
570 * PAGE_KERNEL.
571 */
572 __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL),
573 flags);
574 }
575
576 /*
577 * Map the linear alias of the [_stext, __init_begin) interval
578 * as non-executable now, and remove the write permission in
579 * mark_linear_text_alias_ro() below (which will be called after
580 * alternative patching has completed). This makes the contents
581 * of the region accessible to subsystems such as hibernate,
582 * but protects it from inadvertent modification or execution.
583 * Note that contiguous mappings cannot be remapped in this way,
584 * so we should avoid them here.
585 */
586 __map_memblock(pgdp, kernel_start, kernel_end,
587 PAGE_KERNEL, NO_CONT_MAPPINGS);
588 memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
589
590 /*
591 * Use page-level mappings here so that we can shrink the region
592 * in page granularity and put back unused memory to buddy system
593 * through /sys/kernel/kexec_crash_size interface.
594 */
595 #ifdef CONFIG_KEXEC_CORE
596 if (crash_mem_map && !defer_reserve_crashkernel()) {
597 if (crashk_res.end) {
598 __map_memblock(pgdp, crashk_res.start,
599 crashk_res.end + 1,
600 PAGE_KERNEL,
601 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
602 memblock_clear_nomap(crashk_res.start,
603 resource_size(&crashk_res));
604 }
605 }
606 #endif
607 }
608
mark_rodata_ro(void)609 void mark_rodata_ro(void)
610 {
611 unsigned long section_size;
612
613 /*
614 * mark .rodata as read only. Use __init_begin rather than __end_rodata
615 * to cover NOTES and EXCEPTION_TABLE.
616 */
617 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
618 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata,
619 section_size, PAGE_KERNEL_RO);
620
621 debug_checkwx();
622 }
623
map_kernel_segment(pgd_t * pgdp,void * va_start,void * va_end,pgprot_t prot,struct vm_struct * vma,int flags,unsigned long vm_flags)624 static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end,
625 pgprot_t prot, struct vm_struct *vma,
626 int flags, unsigned long vm_flags)
627 {
628 phys_addr_t pa_start = __pa_symbol(va_start);
629 unsigned long size = va_end - va_start;
630
631 BUG_ON(!PAGE_ALIGNED(pa_start));
632 BUG_ON(!PAGE_ALIGNED(size));
633
634 __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot,
635 early_pgtable_alloc, flags);
636
637 if (!(vm_flags & VM_NO_GUARD))
638 size += PAGE_SIZE;
639
640 vma->addr = va_start;
641 vma->phys_addr = pa_start;
642 vma->size = size;
643 vma->flags = VM_MAP | vm_flags;
644 vma->caller = __builtin_return_address(0);
645
646 vm_area_add_early(vma);
647 }
648
649 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
map_entry_trampoline(void)650 static int __init map_entry_trampoline(void)
651 {
652 int i;
653
654 pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
655 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
656
657 /* The trampoline is always mapped and can therefore be global */
658 pgprot_val(prot) &= ~PTE_NG;
659
660 /* Map only the text into the trampoline page table */
661 memset(tramp_pg_dir, 0, PGD_SIZE);
662 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS,
663 entry_tramp_text_size(), prot,
664 __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS);
665
666 /* Map both the text and data into the kernel page table */
667 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++)
668 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i,
669 pa_start + i * PAGE_SIZE, prot);
670
671 if (IS_ENABLED(CONFIG_RELOCATABLE))
672 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i,
673 pa_start + i * PAGE_SIZE, PAGE_KERNEL_RO);
674
675 return 0;
676 }
677 core_initcall(map_entry_trampoline);
678 #endif
679
680 /*
681 * Open coded check for BTI, only for use to determine configuration
682 * for early mappings for before the cpufeature code has run.
683 */
arm64_early_this_cpu_has_bti(void)684 static bool arm64_early_this_cpu_has_bti(void)
685 {
686 u64 pfr1;
687
688 if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL))
689 return false;
690
691 pfr1 = __read_sysreg_by_encoding(SYS_ID_AA64PFR1_EL1);
692 return cpuid_feature_extract_unsigned_field(pfr1,
693 ID_AA64PFR1_EL1_BT_SHIFT);
694 }
695
696 /*
697 * Create fine-grained mappings for the kernel.
698 */
map_kernel(pgd_t * pgdp)699 static void __init map_kernel(pgd_t *pgdp)
700 {
701 static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext,
702 vmlinux_initdata, vmlinux_data;
703
704 /*
705 * External debuggers may need to write directly to the text
706 * mapping to install SW breakpoints. Allow this (only) when
707 * explicitly requested with rodata=off.
708 */
709 pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
710
711 /*
712 * If we have a CPU that supports BTI and a kernel built for
713 * BTI then mark the kernel executable text as guarded pages
714 * now so we don't have to rewrite the page tables later.
715 */
716 if (arm64_early_this_cpu_has_bti())
717 text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP);
718
719 /*
720 * Only rodata will be remapped with different permissions later on,
721 * all other segments are allowed to use contiguous mappings.
722 */
723 map_kernel_segment(pgdp, _stext, _etext, text_prot, &vmlinux_text, 0,
724 VM_NO_GUARD);
725 map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL,
726 &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD);
727 map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot,
728 &vmlinux_inittext, 0, VM_NO_GUARD);
729 map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL,
730 &vmlinux_initdata, 0, VM_NO_GUARD);
731 map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);
732
733 if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) {
734 /*
735 * The fixmap falls in a separate pgd to the kernel, and doesn't
736 * live in the carveout for the swapper_pg_dir. We can simply
737 * re-use the existing dir for the fixmap.
738 */
739 set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START),
740 READ_ONCE(*pgd_offset_k(FIXADDR_START)));
741 } else if (CONFIG_PGTABLE_LEVELS > 3) {
742 pgd_t *bm_pgdp;
743 p4d_t *bm_p4dp;
744 pud_t *bm_pudp;
745 /*
746 * The fixmap shares its top level pgd entry with the kernel
747 * mapping. This can really only occur when we are running
748 * with 16k/4 levels, so we can simply reuse the pud level
749 * entry instead.
750 */
751 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
752 bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START);
753 bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START);
754 bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START);
755 pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd));
756 pud_clear_fixmap();
757 } else {
758 BUG();
759 }
760
761 kasan_copy_shadow(pgdp);
762 }
763
create_idmap(void)764 static void __init create_idmap(void)
765 {
766 u64 start = __pa_symbol(__idmap_text_start);
767 u64 size = __pa_symbol(__idmap_text_end) - start;
768 pgd_t *pgd = idmap_pg_dir;
769 u64 pgd_phys;
770
771 /* check if we need an additional level of translation */
772 if (VA_BITS < 48 && idmap_t0sz < (64 - VA_BITS_MIN)) {
773 pgd_phys = early_pgtable_alloc(PAGE_SHIFT);
774 set_pgd(&idmap_pg_dir[start >> VA_BITS],
775 __pgd(pgd_phys | P4D_TYPE_TABLE));
776 pgd = __va(pgd_phys);
777 }
778 __create_pgd_mapping(pgd, start, start, size, PAGE_KERNEL_ROX,
779 early_pgtable_alloc, 0);
780
781 if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) {
782 extern u32 __idmap_kpti_flag;
783 u64 pa = __pa_symbol(&__idmap_kpti_flag);
784
785 /*
786 * The KPTI G-to-nG conversion code needs a read-write mapping
787 * of its synchronization flag in the ID map.
788 */
789 __create_pgd_mapping(pgd, pa, pa, sizeof(u32), PAGE_KERNEL,
790 early_pgtable_alloc, 0);
791 }
792 }
793
paging_init(void)794 void __init paging_init(void)
795 {
796 pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir));
797 extern pgd_t init_idmap_pg_dir[];
798
799 idmap_t0sz = 63UL - __fls(__pa_symbol(_end) | GENMASK(VA_BITS_MIN - 1, 0));
800
801 map_kernel(pgdp);
802 map_mem(pgdp);
803
804 pgd_clear_fixmap();
805
806 cpu_replace_ttbr1(lm_alias(swapper_pg_dir), init_idmap_pg_dir);
807 init_mm.pgd = swapper_pg_dir;
808
809 memblock_phys_free(__pa_symbol(init_pg_dir),
810 __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir));
811
812 memblock_allow_resize();
813
814 create_idmap();
815 }
816
817 /*
818 * Check whether a kernel address is valid (derived from arch/x86/).
819 */
kern_addr_valid(unsigned long addr)820 int kern_addr_valid(unsigned long addr)
821 {
822 pgd_t *pgdp;
823 p4d_t *p4dp;
824 pud_t *pudp, pud;
825 pmd_t *pmdp, pmd;
826 pte_t *ptep, pte;
827
828 addr = arch_kasan_reset_tag(addr);
829 if ((((long)addr) >> VA_BITS) != -1UL)
830 return 0;
831
832 pgdp = pgd_offset_k(addr);
833 if (pgd_none(READ_ONCE(*pgdp)))
834 return 0;
835
836 p4dp = p4d_offset(pgdp, addr);
837 if (p4d_none(READ_ONCE(*p4dp)))
838 return 0;
839
840 pudp = pud_offset(p4dp, addr);
841 pud = READ_ONCE(*pudp);
842 if (pud_none(pud))
843 return 0;
844
845 if (pud_sect(pud))
846 return pfn_valid(pud_pfn(pud));
847
848 pmdp = pmd_offset(pudp, addr);
849 pmd = READ_ONCE(*pmdp);
850 if (pmd_none(pmd))
851 return 0;
852
853 if (pmd_sect(pmd))
854 return pfn_valid(pmd_pfn(pmd));
855
856 ptep = pte_offset_kernel(pmdp, addr);
857 pte = READ_ONCE(*ptep);
858 if (pte_none(pte))
859 return 0;
860
861 return pfn_valid(pte_pfn(pte));
862 }
863
864 #ifdef CONFIG_MEMORY_HOTPLUG
free_hotplug_page_range(struct page * page,size_t size,struct vmem_altmap * altmap)865 static void free_hotplug_page_range(struct page *page, size_t size,
866 struct vmem_altmap *altmap)
867 {
868 if (altmap) {
869 vmem_altmap_free(altmap, size >> PAGE_SHIFT);
870 } else {
871 WARN_ON(PageReserved(page));
872 free_pages((unsigned long)page_address(page), get_order(size));
873 }
874 }
875
free_hotplug_pgtable_page(struct page * page)876 static void free_hotplug_pgtable_page(struct page *page)
877 {
878 free_hotplug_page_range(page, PAGE_SIZE, NULL);
879 }
880
pgtable_range_aligned(unsigned long start,unsigned long end,unsigned long floor,unsigned long ceiling,unsigned long mask)881 static bool pgtable_range_aligned(unsigned long start, unsigned long end,
882 unsigned long floor, unsigned long ceiling,
883 unsigned long mask)
884 {
885 start &= mask;
886 if (start < floor)
887 return false;
888
889 if (ceiling) {
890 ceiling &= mask;
891 if (!ceiling)
892 return false;
893 }
894
895 if (end - 1 > ceiling - 1)
896 return false;
897 return true;
898 }
899
unmap_hotplug_pte_range(pmd_t * pmdp,unsigned long addr,unsigned long end,bool free_mapped,struct vmem_altmap * altmap)900 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr,
901 unsigned long end, bool free_mapped,
902 struct vmem_altmap *altmap)
903 {
904 pte_t *ptep, pte;
905
906 do {
907 ptep = pte_offset_kernel(pmdp, addr);
908 pte = READ_ONCE(*ptep);
909 if (pte_none(pte))
910 continue;
911
912 WARN_ON(!pte_present(pte));
913 pte_clear(&init_mm, addr, ptep);
914 flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
915 if (free_mapped)
916 free_hotplug_page_range(pte_page(pte),
917 PAGE_SIZE, altmap);
918 } while (addr += PAGE_SIZE, addr < end);
919 }
920
unmap_hotplug_pmd_range(pud_t * pudp,unsigned long addr,unsigned long end,bool free_mapped,struct vmem_altmap * altmap)921 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr,
922 unsigned long end, bool free_mapped,
923 struct vmem_altmap *altmap)
924 {
925 unsigned long next;
926 pmd_t *pmdp, pmd;
927
928 do {
929 next = pmd_addr_end(addr, end);
930 pmdp = pmd_offset(pudp, addr);
931 pmd = READ_ONCE(*pmdp);
932 if (pmd_none(pmd))
933 continue;
934
935 WARN_ON(!pmd_present(pmd));
936 if (pmd_sect(pmd)) {
937 pmd_clear(pmdp);
938
939 /*
940 * One TLBI should be sufficient here as the PMD_SIZE
941 * range is mapped with a single block entry.
942 */
943 flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
944 if (free_mapped)
945 free_hotplug_page_range(pmd_page(pmd),
946 PMD_SIZE, altmap);
947 continue;
948 }
949 WARN_ON(!pmd_table(pmd));
950 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap);
951 } while (addr = next, addr < end);
952 }
953
unmap_hotplug_pud_range(p4d_t * p4dp,unsigned long addr,unsigned long end,bool free_mapped,struct vmem_altmap * altmap)954 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr,
955 unsigned long end, bool free_mapped,
956 struct vmem_altmap *altmap)
957 {
958 unsigned long next;
959 pud_t *pudp, pud;
960
961 do {
962 next = pud_addr_end(addr, end);
963 pudp = pud_offset(p4dp, addr);
964 pud = READ_ONCE(*pudp);
965 if (pud_none(pud))
966 continue;
967
968 WARN_ON(!pud_present(pud));
969 if (pud_sect(pud)) {
970 pud_clear(pudp);
971
972 /*
973 * One TLBI should be sufficient here as the PUD_SIZE
974 * range is mapped with a single block entry.
975 */
976 flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
977 if (free_mapped)
978 free_hotplug_page_range(pud_page(pud),
979 PUD_SIZE, altmap);
980 continue;
981 }
982 WARN_ON(!pud_table(pud));
983 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap);
984 } while (addr = next, addr < end);
985 }
986
unmap_hotplug_p4d_range(pgd_t * pgdp,unsigned long addr,unsigned long end,bool free_mapped,struct vmem_altmap * altmap)987 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr,
988 unsigned long end, bool free_mapped,
989 struct vmem_altmap *altmap)
990 {
991 unsigned long next;
992 p4d_t *p4dp, p4d;
993
994 do {
995 next = p4d_addr_end(addr, end);
996 p4dp = p4d_offset(pgdp, addr);
997 p4d = READ_ONCE(*p4dp);
998 if (p4d_none(p4d))
999 continue;
1000
1001 WARN_ON(!p4d_present(p4d));
1002 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap);
1003 } while (addr = next, addr < end);
1004 }
1005
unmap_hotplug_range(unsigned long addr,unsigned long end,bool free_mapped,struct vmem_altmap * altmap)1006 static void unmap_hotplug_range(unsigned long addr, unsigned long end,
1007 bool free_mapped, struct vmem_altmap *altmap)
1008 {
1009 unsigned long next;
1010 pgd_t *pgdp, pgd;
1011
1012 /*
1013 * altmap can only be used as vmemmap mapping backing memory.
1014 * In case the backing memory itself is not being freed, then
1015 * altmap is irrelevant. Warn about this inconsistency when
1016 * encountered.
1017 */
1018 WARN_ON(!free_mapped && altmap);
1019
1020 do {
1021 next = pgd_addr_end(addr, end);
1022 pgdp = pgd_offset_k(addr);
1023 pgd = READ_ONCE(*pgdp);
1024 if (pgd_none(pgd))
1025 continue;
1026
1027 WARN_ON(!pgd_present(pgd));
1028 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap);
1029 } while (addr = next, addr < end);
1030 }
1031
free_empty_pte_table(pmd_t * pmdp,unsigned long addr,unsigned long end,unsigned long floor,unsigned long ceiling)1032 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr,
1033 unsigned long end, unsigned long floor,
1034 unsigned long ceiling)
1035 {
1036 pte_t *ptep, pte;
1037 unsigned long i, start = addr;
1038
1039 do {
1040 ptep = pte_offset_kernel(pmdp, addr);
1041 pte = READ_ONCE(*ptep);
1042
1043 /*
1044 * This is just a sanity check here which verifies that
1045 * pte clearing has been done by earlier unmap loops.
1046 */
1047 WARN_ON(!pte_none(pte));
1048 } while (addr += PAGE_SIZE, addr < end);
1049
1050 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK))
1051 return;
1052
1053 /*
1054 * Check whether we can free the pte page if the rest of the
1055 * entries are empty. Overlap with other regions have been
1056 * handled by the floor/ceiling check.
1057 */
1058 ptep = pte_offset_kernel(pmdp, 0UL);
1059 for (i = 0; i < PTRS_PER_PTE; i++) {
1060 if (!pte_none(READ_ONCE(ptep[i])))
1061 return;
1062 }
1063
1064 pmd_clear(pmdp);
1065 __flush_tlb_kernel_pgtable(start);
1066 free_hotplug_pgtable_page(virt_to_page(ptep));
1067 }
1068
free_empty_pmd_table(pud_t * pudp,unsigned long addr,unsigned long end,unsigned long floor,unsigned long ceiling)1069 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr,
1070 unsigned long end, unsigned long floor,
1071 unsigned long ceiling)
1072 {
1073 pmd_t *pmdp, pmd;
1074 unsigned long i, next, start = addr;
1075
1076 do {
1077 next = pmd_addr_end(addr, end);
1078 pmdp = pmd_offset(pudp, addr);
1079 pmd = READ_ONCE(*pmdp);
1080 if (pmd_none(pmd))
1081 continue;
1082
1083 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd));
1084 free_empty_pte_table(pmdp, addr, next, floor, ceiling);
1085 } while (addr = next, addr < end);
1086
1087 if (CONFIG_PGTABLE_LEVELS <= 2)
1088 return;
1089
1090 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK))
1091 return;
1092
1093 /*
1094 * Check whether we can free the pmd page if the rest of the
1095 * entries are empty. Overlap with other regions have been
1096 * handled by the floor/ceiling check.
1097 */
1098 pmdp = pmd_offset(pudp, 0UL);
1099 for (i = 0; i < PTRS_PER_PMD; i++) {
1100 if (!pmd_none(READ_ONCE(pmdp[i])))
1101 return;
1102 }
1103
1104 pud_clear(pudp);
1105 __flush_tlb_kernel_pgtable(start);
1106 free_hotplug_pgtable_page(virt_to_page(pmdp));
1107 }
1108
free_empty_pud_table(p4d_t * p4dp,unsigned long addr,unsigned long end,unsigned long floor,unsigned long ceiling)1109 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr,
1110 unsigned long end, unsigned long floor,
1111 unsigned long ceiling)
1112 {
1113 pud_t *pudp, pud;
1114 unsigned long i, next, start = addr;
1115
1116 do {
1117 next = pud_addr_end(addr, end);
1118 pudp = pud_offset(p4dp, addr);
1119 pud = READ_ONCE(*pudp);
1120 if (pud_none(pud))
1121 continue;
1122
1123 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud));
1124 free_empty_pmd_table(pudp, addr, next, floor, ceiling);
1125 } while (addr = next, addr < end);
1126
1127 if (CONFIG_PGTABLE_LEVELS <= 3)
1128 return;
1129
1130 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK))
1131 return;
1132
1133 /*
1134 * Check whether we can free the pud page if the rest of the
1135 * entries are empty. Overlap with other regions have been
1136 * handled by the floor/ceiling check.
1137 */
1138 pudp = pud_offset(p4dp, 0UL);
1139 for (i = 0; i < PTRS_PER_PUD; i++) {
1140 if (!pud_none(READ_ONCE(pudp[i])))
1141 return;
1142 }
1143
1144 p4d_clear(p4dp);
1145 __flush_tlb_kernel_pgtable(start);
1146 free_hotplug_pgtable_page(virt_to_page(pudp));
1147 }
1148
free_empty_p4d_table(pgd_t * pgdp,unsigned long addr,unsigned long end,unsigned long floor,unsigned long ceiling)1149 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr,
1150 unsigned long end, unsigned long floor,
1151 unsigned long ceiling)
1152 {
1153 unsigned long next;
1154 p4d_t *p4dp, p4d;
1155
1156 do {
1157 next = p4d_addr_end(addr, end);
1158 p4dp = p4d_offset(pgdp, addr);
1159 p4d = READ_ONCE(*p4dp);
1160 if (p4d_none(p4d))
1161 continue;
1162
1163 WARN_ON(!p4d_present(p4d));
1164 free_empty_pud_table(p4dp, addr, next, floor, ceiling);
1165 } while (addr = next, addr < end);
1166 }
1167
free_empty_tables(unsigned long addr,unsigned long end,unsigned long floor,unsigned long ceiling)1168 static void free_empty_tables(unsigned long addr, unsigned long end,
1169 unsigned long floor, unsigned long ceiling)
1170 {
1171 unsigned long next;
1172 pgd_t *pgdp, pgd;
1173
1174 do {
1175 next = pgd_addr_end(addr, end);
1176 pgdp = pgd_offset_k(addr);
1177 pgd = READ_ONCE(*pgdp);
1178 if (pgd_none(pgd))
1179 continue;
1180
1181 WARN_ON(!pgd_present(pgd));
1182 free_empty_p4d_table(pgdp, addr, next, floor, ceiling);
1183 } while (addr = next, addr < end);
1184 }
1185 #endif
1186
vmemmap_populate(unsigned long start,unsigned long end,int node,struct vmem_altmap * altmap)1187 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
1188 struct vmem_altmap *altmap)
1189 {
1190 unsigned long addr = start;
1191 unsigned long next;
1192 pgd_t *pgdp;
1193 p4d_t *p4dp;
1194 pud_t *pudp;
1195 pmd_t *pmdp;
1196
1197 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));
1198
1199 if (!ARM64_KERNEL_USES_PMD_MAPS)
1200 return vmemmap_populate_basepages(start, end, node, altmap);
1201
1202 do {
1203 next = pmd_addr_end(addr, end);
1204
1205 pgdp = vmemmap_pgd_populate(addr, node);
1206 if (!pgdp)
1207 return -ENOMEM;
1208
1209 p4dp = vmemmap_p4d_populate(pgdp, addr, node);
1210 if (!p4dp)
1211 return -ENOMEM;
1212
1213 pudp = vmemmap_pud_populate(p4dp, addr, node);
1214 if (!pudp)
1215 return -ENOMEM;
1216
1217 pmdp = pmd_offset(pudp, addr);
1218 if (pmd_none(READ_ONCE(*pmdp))) {
1219 void *p = NULL;
1220
1221 p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap);
1222 if (!p) {
1223 if (vmemmap_populate_basepages(addr, next, node, altmap))
1224 return -ENOMEM;
1225 continue;
1226 }
1227
1228 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL));
1229 } else
1230 vmemmap_verify((pte_t *)pmdp, node, addr, next);
1231 } while (addr = next, addr != end);
1232
1233 return 0;
1234 }
1235
1236 #ifdef CONFIG_MEMORY_HOTPLUG
vmemmap_free(unsigned long start,unsigned long end,struct vmem_altmap * altmap)1237 void vmemmap_free(unsigned long start, unsigned long end,
1238 struct vmem_altmap *altmap)
1239 {
1240 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));
1241
1242 unmap_hotplug_range(start, end, true, altmap);
1243 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END);
1244 }
1245 #endif /* CONFIG_MEMORY_HOTPLUG */
1246
fixmap_pud(unsigned long addr)1247 static inline pud_t *fixmap_pud(unsigned long addr)
1248 {
1249 pgd_t *pgdp = pgd_offset_k(addr);
1250 p4d_t *p4dp = p4d_offset(pgdp, addr);
1251 p4d_t p4d = READ_ONCE(*p4dp);
1252
1253 BUG_ON(p4d_none(p4d) || p4d_bad(p4d));
1254
1255 return pud_offset_kimg(p4dp, addr);
1256 }
1257
fixmap_pmd(unsigned long addr)1258 static inline pmd_t *fixmap_pmd(unsigned long addr)
1259 {
1260 pud_t *pudp = fixmap_pud(addr);
1261 pud_t pud = READ_ONCE(*pudp);
1262
1263 BUG_ON(pud_none(pud) || pud_bad(pud));
1264
1265 return pmd_offset_kimg(pudp, addr);
1266 }
1267
fixmap_pte(unsigned long addr)1268 static inline pte_t *fixmap_pte(unsigned long addr)
1269 {
1270 return &bm_pte[pte_index(addr)];
1271 }
1272
1273 /*
1274 * The p*d_populate functions call virt_to_phys implicitly so they can't be used
1275 * directly on kernel symbols (bm_p*d). This function is called too early to use
1276 * lm_alias so __p*d_populate functions must be used to populate with the
1277 * physical address from __pa_symbol.
1278 */
early_fixmap_init(void)1279 void __init early_fixmap_init(void)
1280 {
1281 pgd_t *pgdp;
1282 p4d_t *p4dp, p4d;
1283 pud_t *pudp;
1284 pmd_t *pmdp;
1285 unsigned long addr = FIXADDR_START;
1286
1287 pgdp = pgd_offset_k(addr);
1288 p4dp = p4d_offset(pgdp, addr);
1289 p4d = READ_ONCE(*p4dp);
1290 if (CONFIG_PGTABLE_LEVELS > 3 &&
1291 !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) {
1292 /*
1293 * We only end up here if the kernel mapping and the fixmap
1294 * share the top level pgd entry, which should only happen on
1295 * 16k/4 levels configurations.
1296 */
1297 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
1298 pudp = pud_offset_kimg(p4dp, addr);
1299 } else {
1300 if (p4d_none(p4d))
1301 __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE);
1302 pudp = fixmap_pud(addr);
1303 }
1304 if (pud_none(READ_ONCE(*pudp)))
1305 __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE);
1306 pmdp = fixmap_pmd(addr);
1307 __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE);
1308
1309 /*
1310 * The boot-ioremap range spans multiple pmds, for which
1311 * we are not prepared:
1312 */
1313 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
1314 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
1315
1316 if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
1317 || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
1318 WARN_ON(1);
1319 pr_warn("pmdp %p != %p, %p\n",
1320 pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
1321 fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
1322 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
1323 fix_to_virt(FIX_BTMAP_BEGIN));
1324 pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n",
1325 fix_to_virt(FIX_BTMAP_END));
1326
1327 pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END);
1328 pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN);
1329 }
1330 }
1331
1332 /*
1333 * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we
1334 * ever need to use IPIs for TLB broadcasting, then we're in trouble here.
1335 */
__set_fixmap(enum fixed_addresses idx,phys_addr_t phys,pgprot_t flags)1336 void __set_fixmap(enum fixed_addresses idx,
1337 phys_addr_t phys, pgprot_t flags)
1338 {
1339 unsigned long addr = __fix_to_virt(idx);
1340 pte_t *ptep;
1341
1342 BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
1343
1344 ptep = fixmap_pte(addr);
1345
1346 if (pgprot_val(flags)) {
1347 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags));
1348 } else {
1349 pte_clear(&init_mm, addr, ptep);
1350 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
1351 }
1352 }
1353
fixmap_remap_fdt(phys_addr_t dt_phys,int * size,pgprot_t prot)1354 void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
1355 {
1356 const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
1357 int offset;
1358 void *dt_virt;
1359
1360 /*
1361 * Check whether the physical FDT address is set and meets the minimum
1362 * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
1363 * at least 8 bytes so that we can always access the magic and size
1364 * fields of the FDT header after mapping the first chunk, double check
1365 * here if that is indeed the case.
1366 */
1367 BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
1368 if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
1369 return NULL;
1370
1371 /*
1372 * Make sure that the FDT region can be mapped without the need to
1373 * allocate additional translation table pages, so that it is safe
1374 * to call create_mapping_noalloc() this early.
1375 *
1376 * On 64k pages, the FDT will be mapped using PTEs, so we need to
1377 * be in the same PMD as the rest of the fixmap.
1378 * On 4k pages, we'll use section mappings for the FDT so we only
1379 * have to be in the same PUD.
1380 */
1381 BUILD_BUG_ON(dt_virt_base % SZ_2M);
1382
1383 BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
1384 __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
1385
1386 offset = dt_phys % SWAPPER_BLOCK_SIZE;
1387 dt_virt = (void *)dt_virt_base + offset;
1388
1389 /* map the first chunk so we can read the size from the header */
1390 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
1391 dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
1392
1393 if (fdt_magic(dt_virt) != FDT_MAGIC)
1394 return NULL;
1395
1396 *size = fdt_totalsize(dt_virt);
1397 if (*size > MAX_FDT_SIZE)
1398 return NULL;
1399
1400 if (offset + *size > SWAPPER_BLOCK_SIZE)
1401 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
1402 round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
1403
1404 return dt_virt;
1405 }
1406
pud_set_huge(pud_t * pudp,phys_addr_t phys,pgprot_t prot)1407 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
1408 {
1409 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));
1410
1411 /* Only allow permission changes for now */
1412 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)),
1413 pud_val(new_pud)))
1414 return 0;
1415
1416 VM_BUG_ON(phys & ~PUD_MASK);
1417 set_pud(pudp, new_pud);
1418 return 1;
1419 }
1420
pmd_set_huge(pmd_t * pmdp,phys_addr_t phys,pgprot_t prot)1421 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
1422 {
1423 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot));
1424
1425 /* Only allow permission changes for now */
1426 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)),
1427 pmd_val(new_pmd)))
1428 return 0;
1429
1430 VM_BUG_ON(phys & ~PMD_MASK);
1431 set_pmd(pmdp, new_pmd);
1432 return 1;
1433 }
1434
pud_clear_huge(pud_t * pudp)1435 int pud_clear_huge(pud_t *pudp)
1436 {
1437 if (!pud_sect(READ_ONCE(*pudp)))
1438 return 0;
1439 pud_clear(pudp);
1440 return 1;
1441 }
1442
pmd_clear_huge(pmd_t * pmdp)1443 int pmd_clear_huge(pmd_t *pmdp)
1444 {
1445 if (!pmd_sect(READ_ONCE(*pmdp)))
1446 return 0;
1447 pmd_clear(pmdp);
1448 return 1;
1449 }
1450
pmd_free_pte_page(pmd_t * pmdp,unsigned long addr)1451 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr)
1452 {
1453 pte_t *table;
1454 pmd_t pmd;
1455
1456 pmd = READ_ONCE(*pmdp);
1457
1458 if (!pmd_table(pmd)) {
1459 VM_WARN_ON(1);
1460 return 1;
1461 }
1462
1463 table = pte_offset_kernel(pmdp, addr);
1464 pmd_clear(pmdp);
1465 __flush_tlb_kernel_pgtable(addr);
1466 pte_free_kernel(NULL, table);
1467 return 1;
1468 }
1469
pud_free_pmd_page(pud_t * pudp,unsigned long addr)1470 int pud_free_pmd_page(pud_t *pudp, unsigned long addr)
1471 {
1472 pmd_t *table;
1473 pmd_t *pmdp;
1474 pud_t pud;
1475 unsigned long next, end;
1476
1477 pud = READ_ONCE(*pudp);
1478
1479 if (!pud_table(pud)) {
1480 VM_WARN_ON(1);
1481 return 1;
1482 }
1483
1484 table = pmd_offset(pudp, addr);
1485 pmdp = table;
1486 next = addr;
1487 end = addr + PUD_SIZE;
1488 do {
1489 pmd_free_pte_page(pmdp, next);
1490 } while (pmdp++, next += PMD_SIZE, next != end);
1491
1492 pud_clear(pudp);
1493 __flush_tlb_kernel_pgtable(addr);
1494 pmd_free(NULL, table);
1495 return 1;
1496 }
1497
1498 #ifdef CONFIG_MEMORY_HOTPLUG
__remove_pgd_mapping(pgd_t * pgdir,unsigned long start,u64 size)1499 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size)
1500 {
1501 unsigned long end = start + size;
1502
1503 WARN_ON(pgdir != init_mm.pgd);
1504 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END));
1505
1506 unmap_hotplug_range(start, end, false, NULL);
1507 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END);
1508 }
1509
arch_get_mappable_range(void)1510 struct range arch_get_mappable_range(void)
1511 {
1512 struct range mhp_range;
1513 u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual));
1514 u64 end_linear_pa = __pa(PAGE_END - 1);
1515
1516 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
1517 /*
1518 * Check for a wrap, it is possible because of randomized linear
1519 * mapping the start physical address is actually bigger than
1520 * the end physical address. In this case set start to zero
1521 * because [0, end_linear_pa] range must still be able to cover
1522 * all addressable physical addresses.
1523 */
1524 if (start_linear_pa > end_linear_pa)
1525 start_linear_pa = 0;
1526 }
1527
1528 WARN_ON(start_linear_pa > end_linear_pa);
1529
1530 /*
1531 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)]
1532 * accommodating both its ends but excluding PAGE_END. Max physical
1533 * range which can be mapped inside this linear mapping range, must
1534 * also be derived from its end points.
1535 */
1536 mhp_range.start = start_linear_pa;
1537 mhp_range.end = end_linear_pa;
1538
1539 return mhp_range;
1540 }
1541
arch_add_memory(int nid,u64 start,u64 size,struct mhp_params * params)1542 int arch_add_memory(int nid, u64 start, u64 size,
1543 struct mhp_params *params)
1544 {
1545 int ret, flags = NO_EXEC_MAPPINGS;
1546
1547 VM_BUG_ON(!mhp_range_allowed(start, size, true));
1548
1549 if (can_set_direct_map())
1550 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
1551
1552 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
1553 size, params->pgprot, __pgd_pgtable_alloc,
1554 flags);
1555
1556 memblock_clear_nomap(start, size);
1557
1558 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT,
1559 params);
1560 if (ret)
1561 __remove_pgd_mapping(swapper_pg_dir,
1562 __phys_to_virt(start), size);
1563 else {
1564 max_pfn = PFN_UP(start + size);
1565 max_low_pfn = max_pfn;
1566 }
1567
1568 return ret;
1569 }
1570
arch_remove_memory(u64 start,u64 size,struct vmem_altmap * altmap)1571 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
1572 {
1573 unsigned long start_pfn = start >> PAGE_SHIFT;
1574 unsigned long nr_pages = size >> PAGE_SHIFT;
1575
1576 __remove_pages(start_pfn, nr_pages, altmap);
1577 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size);
1578 }
1579
1580 /*
1581 * This memory hotplug notifier helps prevent boot memory from being
1582 * inadvertently removed as it blocks pfn range offlining process in
1583 * __offline_pages(). Hence this prevents both offlining as well as
1584 * removal process for boot memory which is initially always online.
1585 * In future if and when boot memory could be removed, this notifier
1586 * should be dropped and free_hotplug_page_range() should handle any
1587 * reserved pages allocated during boot.
1588 */
prevent_bootmem_remove_notifier(struct notifier_block * nb,unsigned long action,void * data)1589 static int prevent_bootmem_remove_notifier(struct notifier_block *nb,
1590 unsigned long action, void *data)
1591 {
1592 struct mem_section *ms;
1593 struct memory_notify *arg = data;
1594 unsigned long end_pfn = arg->start_pfn + arg->nr_pages;
1595 unsigned long pfn = arg->start_pfn;
1596
1597 if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE))
1598 return NOTIFY_OK;
1599
1600 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1601 unsigned long start = PFN_PHYS(pfn);
1602 unsigned long end = start + (1UL << PA_SECTION_SHIFT);
1603
1604 ms = __pfn_to_section(pfn);
1605 if (!early_section(ms))
1606 continue;
1607
1608 if (action == MEM_GOING_OFFLINE) {
1609 /*
1610 * Boot memory removal is not supported. Prevent
1611 * it via blocking any attempted offline request
1612 * for the boot memory and just report it.
1613 */
1614 pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end);
1615 return NOTIFY_BAD;
1616 } else if (action == MEM_OFFLINE) {
1617 /*
1618 * This should have never happened. Boot memory
1619 * offlining should have been prevented by this
1620 * very notifier. Probably some memory removal
1621 * procedure might have changed which would then
1622 * require further debug.
1623 */
1624 pr_err("Boot memory [%lx %lx] offlined\n", start, end);
1625
1626 /*
1627 * Core memory hotplug does not process a return
1628 * code from the notifier for MEM_OFFLINE events.
1629 * The error condition has been reported. Return
1630 * from here as if ignored.
1631 */
1632 return NOTIFY_DONE;
1633 }
1634 }
1635 return NOTIFY_OK;
1636 }
1637
1638 static struct notifier_block prevent_bootmem_remove_nb = {
1639 .notifier_call = prevent_bootmem_remove_notifier,
1640 };
1641
1642 /*
1643 * This ensures that boot memory sections on the platform are online
1644 * from early boot. Memory sections could not be prevented from being
1645 * offlined, unless for some reason they are not online to begin with.
1646 * This helps validate the basic assumption on which the above memory
1647 * event notifier works to prevent boot memory section offlining and
1648 * its possible removal.
1649 */
validate_bootmem_online(void)1650 static void validate_bootmem_online(void)
1651 {
1652 phys_addr_t start, end, addr;
1653 struct mem_section *ms;
1654 u64 i;
1655
1656 /*
1657 * Scanning across all memblock might be expensive
1658 * on some big memory systems. Hence enable this
1659 * validation only with DEBUG_VM.
1660 */
1661 if (!IS_ENABLED(CONFIG_DEBUG_VM))
1662 return;
1663
1664 for_each_mem_range(i, &start, &end) {
1665 for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) {
1666 ms = __pfn_to_section(PHYS_PFN(addr));
1667
1668 /*
1669 * All memory ranges in the system at this point
1670 * should have been marked as early sections.
1671 */
1672 WARN_ON(!early_section(ms));
1673
1674 /*
1675 * Memory notifier mechanism here to prevent boot
1676 * memory offlining depends on the fact that each
1677 * early section memory on the system is initially
1678 * online. Otherwise a given memory section which
1679 * is already offline will be overlooked and can
1680 * be removed completely. Call out such sections.
1681 */
1682 if (!online_section(ms))
1683 pr_err("Boot memory [%llx %llx] is offline, can be removed\n",
1684 addr, addr + (1UL << PA_SECTION_SHIFT));
1685 }
1686 }
1687 }
1688
prevent_bootmem_remove_init(void)1689 static int __init prevent_bootmem_remove_init(void)
1690 {
1691 int ret = 0;
1692
1693 if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
1694 return ret;
1695
1696 validate_bootmem_online();
1697 ret = register_memory_notifier(&prevent_bootmem_remove_nb);
1698 if (ret)
1699 pr_err("%s: Notifier registration failed %d\n", __func__, ret);
1700
1701 return ret;
1702 }
1703 early_initcall(prevent_bootmem_remove_init);
1704 #endif
1705