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#include <linux/kfence.h>
28
29#include <asm/barrier.h>
30#include <asm/cputype.h>
31#include <asm/fixmap.h>
32#include <asm/kasan.h>
33#include <asm/kernel-pgtable.h>
34#include <asm/sections.h>
35#include <asm/setup.h>
36#include <linux/sizes.h>
37#include <asm/tlb.h>
38#include <asm/mmu_context.h>
39#include <asm/ptdump.h>
40#include <asm/tlbflush.h>
41#include <asm/pgalloc.h>
42#include <asm/kfence.h>
43
44#define NO_BLOCK_MAPPINGS BIT(0)
45#define NO_CONT_MAPPINGS BIT(1)
46#define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */
47
48u64 kimage_voffset __ro_after_init;
49EXPORT_SYMBOL(kimage_voffset);
50
51u32 __boot_cpu_mode[] = { BOOT_CPU_MODE_EL2, BOOT_CPU_MODE_EL1 };
52
53static bool rodata_is_rw __ro_after_init = true;
54
55/*
56 * The booting CPU updates the failed status @__early_cpu_boot_status,
57 * with MMU turned off.
58 */
59long __section(".mmuoff.data.write") __early_cpu_boot_status;
60
61/*
62 * Empty_zero_page is a special page that is used for zero-initialized data
63 * and COW.
64 */
65unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
66EXPORT_SYMBOL(empty_zero_page);
67
68static DEFINE_SPINLOCK(swapper_pgdir_lock);
69static DEFINE_MUTEX(fixmap_lock);
70
71void noinstr set_swapper_pgd(pgd_t *pgdp, pgd_t pgd)
72{
73 pgd_t *fixmap_pgdp;
74
75 /*
76 * Don't bother with the fixmap if swapper_pg_dir is still mapped
77 * writable in the kernel mapping.
78 */
79 if (rodata_is_rw) {
80 WRITE_ONCE(*pgdp, pgd);
81 dsb(ishst);
82 isb();
83 return;
84 }
85
86 spin_lock(lock: &swapper_pgdir_lock);
87 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp));
88 WRITE_ONCE(*fixmap_pgdp, pgd);
89 /*
90 * We need dsb(ishst) here to ensure the page-table-walker sees
91 * our new entry before set_p?d() returns. The fixmap's
92 * flush_tlb_kernel_range() via clear_fixmap() does this for us.
93 */
94 pgd_clear_fixmap();
95 spin_unlock(lock: &swapper_pgdir_lock);
96}
97
98pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
99 unsigned long size, pgprot_t vma_prot)
100{
101 if (!pfn_is_map_memory(pfn))
102 return pgprot_noncached(vma_prot);
103 else if (file->f_flags & O_SYNC)
104 return pgprot_writecombine(prot: vma_prot);
105 return vma_prot;
106}
107EXPORT_SYMBOL(phys_mem_access_prot);
108
109static phys_addr_t __init early_pgtable_alloc(int shift)
110{
111 phys_addr_t phys;
112 void *ptr;
113
114 phys = memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE, start: 0,
115 MEMBLOCK_ALLOC_NOLEAKTRACE);
116 if (!phys)
117 panic(fmt: "Failed to allocate page table page\n");
118
119 /*
120 * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
121 * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
122 * any level of table.
123 */
124 ptr = pte_set_fixmap(phys);
125
126 memset(ptr, 0, PAGE_SIZE);
127
128 /*
129 * Implicit barriers also ensure the zeroed page is visible to the page
130 * table walker
131 */
132 pte_clear_fixmap();
133
134 return phys;
135}
136
137bool pgattr_change_is_safe(u64 old, u64 new)
138{
139 /*
140 * The following mapping attributes may be updated in live
141 * kernel mappings without the need for break-before-make.
142 */
143 pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG;
144
145 /* creating or taking down mappings is always safe */
146 if (!pte_valid(__pte(val: old)) || !pte_valid(__pte(val: new)))
147 return true;
148
149 /* A live entry's pfn should not change */
150 if (pte_pfn(pte: __pte(val: old)) != pte_pfn(pte: __pte(val: new)))
151 return false;
152
153 /* live contiguous mappings may not be manipulated at all */
154 if ((old | new) & PTE_CONT)
155 return false;
156
157 /* Transitioning from Non-Global to Global is unsafe */
158 if (old & ~new & PTE_NG)
159 return false;
160
161 /*
162 * Changing the memory type between Normal and Normal-Tagged is safe
163 * since Tagged is considered a permission attribute from the
164 * mismatched attribute aliases perspective.
165 */
166 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) ||
167 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) &&
168 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) ||
169 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)))
170 mask |= PTE_ATTRINDX_MASK;
171
172 return ((old ^ new) & ~mask) == 0;
173}
174
175static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
176 phys_addr_t phys, pgprot_t prot)
177{
178 pte_t *ptep;
179
180 ptep = pte_set_fixmap_offset(pmdp, addr);
181 do {
182 pte_t old_pte = __ptep_get(ptep);
183
184 __set_pte(ptep, pfn_pte(__phys_to_pfn(phys), pgprot: prot));
185
186 /*
187 * After the PTE entry has been populated once, we
188 * only allow updates to the permission attributes.
189 */
190 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte),
191 pte_val(__ptep_get(ptep))));
192
193 phys += PAGE_SIZE;
194 } while (ptep++, addr += PAGE_SIZE, addr != end);
195
196 pte_clear_fixmap();
197}
198
199static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr,
200 unsigned long end, phys_addr_t phys,
201 pgprot_t prot,
202 phys_addr_t (*pgtable_alloc)(int),
203 int flags)
204{
205 unsigned long next;
206 pmd_t pmd = READ_ONCE(*pmdp);
207
208 BUG_ON(pmd_sect(pmd));
209 if (pmd_none(pmd)) {
210 pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN;
211 phys_addr_t pte_phys;
212
213 if (flags & NO_EXEC_MAPPINGS)
214 pmdval |= PMD_TABLE_PXN;
215 BUG_ON(!pgtable_alloc);
216 pte_phys = pgtable_alloc(PAGE_SHIFT);
217 __pmd_populate(pmdp, pte_phys, pmdval);
218 pmd = READ_ONCE(*pmdp);
219 }
220 BUG_ON(pmd_bad(pmd));
221
222 do {
223 pgprot_t __prot = prot;
224
225 next = pte_cont_addr_end(addr, end);
226
227 /* use a contiguous mapping if the range is suitably aligned */
228 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) &&
229 (flags & NO_CONT_MAPPINGS) == 0)
230 __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
231
232 init_pte(pmdp, addr, end: next, phys, prot: __prot);
233
234 phys += next - addr;
235 } while (addr = next, addr != end);
236}
237
238static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end,
239 phys_addr_t phys, pgprot_t prot,
240 phys_addr_t (*pgtable_alloc)(int), int flags)
241{
242 unsigned long next;
243 pmd_t *pmdp;
244
245 pmdp = pmd_set_fixmap_offset(pudp, addr);
246 do {
247 pmd_t old_pmd = READ_ONCE(*pmdp);
248
249 next = pmd_addr_end(addr, end);
250
251 /* try section mapping first */
252 if (((addr | next | phys) & ~PMD_MASK) == 0 &&
253 (flags & NO_BLOCK_MAPPINGS) == 0) {
254 pmd_set_huge(pmd: pmdp, addr: phys, prot);
255
256 /*
257 * After the PMD entry has been populated once, we
258 * only allow updates to the permission attributes.
259 */
260 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd),
261 READ_ONCE(pmd_val(*pmdp))));
262 } else {
263 alloc_init_cont_pte(pmdp, addr, end: next, phys, prot,
264 pgtable_alloc, flags);
265
266 BUG_ON(pmd_val(old_pmd) != 0 &&
267 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp)));
268 }
269 phys += next - addr;
270 } while (pmdp++, addr = next, addr != end);
271
272 pmd_clear_fixmap();
273}
274
275static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr,
276 unsigned long end, phys_addr_t phys,
277 pgprot_t prot,
278 phys_addr_t (*pgtable_alloc)(int), int flags)
279{
280 unsigned long next;
281 pud_t pud = READ_ONCE(*pudp);
282
283 /*
284 * Check for initial section mappings in the pgd/pud.
285 */
286 BUG_ON(pud_sect(pud));
287 if (pud_none(pud)) {
288 pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN;
289 phys_addr_t pmd_phys;
290
291 if (flags & NO_EXEC_MAPPINGS)
292 pudval |= PUD_TABLE_PXN;
293 BUG_ON(!pgtable_alloc);
294 pmd_phys = pgtable_alloc(PMD_SHIFT);
295 __pud_populate(pudp, pmd_phys, pudval);
296 pud = READ_ONCE(*pudp);
297 }
298 BUG_ON(pud_bad(pud));
299
300 do {
301 pgprot_t __prot = prot;
302
303 next = pmd_cont_addr_end(addr, end);
304
305 /* use a contiguous mapping if the range is suitably aligned */
306 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) &&
307 (flags & NO_CONT_MAPPINGS) == 0)
308 __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
309
310 init_pmd(pudp, addr, end: next, phys, prot: __prot, pgtable_alloc, flags);
311
312 phys += next - addr;
313 } while (addr = next, addr != end);
314}
315
316static void alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end,
317 phys_addr_t phys, pgprot_t prot,
318 phys_addr_t (*pgtable_alloc)(int),
319 int flags)
320{
321 unsigned long next;
322 p4d_t p4d = READ_ONCE(*p4dp);
323 pud_t *pudp;
324
325 if (p4d_none(p4d)) {
326 p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN;
327 phys_addr_t pud_phys;
328
329 if (flags & NO_EXEC_MAPPINGS)
330 p4dval |= P4D_TABLE_PXN;
331 BUG_ON(!pgtable_alloc);
332 pud_phys = pgtable_alloc(PUD_SHIFT);
333 __p4d_populate(p4dp, pud_phys, p4dval);
334 p4d = READ_ONCE(*p4dp);
335 }
336 BUG_ON(p4d_bad(p4d));
337
338 pudp = pud_set_fixmap_offset(p4dp, addr);
339 do {
340 pud_t old_pud = READ_ONCE(*pudp);
341
342 next = pud_addr_end(addr, end);
343
344 /*
345 * For 4K granule only, attempt to put down a 1GB block
346 */
347 if (pud_sect_supported() &&
348 ((addr | next | phys) & ~PUD_MASK) == 0 &&
349 (flags & NO_BLOCK_MAPPINGS) == 0) {
350 pud_set_huge(pud: pudp, addr: phys, prot);
351
352 /*
353 * After the PUD entry has been populated once, we
354 * only allow updates to the permission attributes.
355 */
356 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud),
357 READ_ONCE(pud_val(*pudp))));
358 } else {
359 alloc_init_cont_pmd(pudp, addr, end: next, phys, prot,
360 pgtable_alloc, flags);
361
362 BUG_ON(pud_val(old_pud) != 0 &&
363 pud_val(old_pud) != READ_ONCE(pud_val(*pudp)));
364 }
365 phys += next - addr;
366 } while (pudp++, addr = next, addr != end);
367
368 pud_clear_fixmap();
369}
370
371static void alloc_init_p4d(pgd_t *pgdp, unsigned long addr, unsigned long end,
372 phys_addr_t phys, pgprot_t prot,
373 phys_addr_t (*pgtable_alloc)(int),
374 int flags)
375{
376 unsigned long next;
377 pgd_t pgd = READ_ONCE(*pgdp);
378 p4d_t *p4dp;
379
380 if (pgd_none(pgd)) {
381 pgdval_t pgdval = PGD_TYPE_TABLE | PGD_TABLE_UXN;
382 phys_addr_t p4d_phys;
383
384 if (flags & NO_EXEC_MAPPINGS)
385 pgdval |= PGD_TABLE_PXN;
386 BUG_ON(!pgtable_alloc);
387 p4d_phys = pgtable_alloc(P4D_SHIFT);
388 __pgd_populate(pgdp, p4d_phys, pgdval);
389 pgd = READ_ONCE(*pgdp);
390 }
391 BUG_ON(pgd_bad(pgd));
392
393 p4dp = p4d_set_fixmap_offset(pgdp, addr);
394 do {
395 p4d_t old_p4d = READ_ONCE(*p4dp);
396
397 next = p4d_addr_end(addr, end);
398
399 alloc_init_pud(p4dp, addr, end: next, phys, prot,
400 pgtable_alloc, flags);
401
402 BUG_ON(p4d_val(old_p4d) != 0 &&
403 p4d_val(old_p4d) != READ_ONCE(p4d_val(*p4dp)));
404
405 phys += next - addr;
406 } while (p4dp++, addr = next, addr != end);
407
408 p4d_clear_fixmap();
409}
410
411static void __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys,
412 unsigned long virt, phys_addr_t size,
413 pgprot_t prot,
414 phys_addr_t (*pgtable_alloc)(int),
415 int flags)
416{
417 unsigned long addr, end, next;
418 pgd_t *pgdp = pgd_offset_pgd(pgd: pgdir, address: virt);
419
420 /*
421 * If the virtual and physical address don't have the same offset
422 * within a page, we cannot map the region as the caller expects.
423 */
424 if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
425 return;
426
427 phys &= PAGE_MASK;
428 addr = virt & PAGE_MASK;
429 end = PAGE_ALIGN(virt + size);
430
431 do {
432 next = pgd_addr_end(addr, end);
433 alloc_init_p4d(pgdp, addr, end: next, phys, prot, pgtable_alloc,
434 flags);
435 phys += next - addr;
436 } while (pgdp++, addr = next, addr != end);
437}
438
439static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
440 unsigned long virt, phys_addr_t size,
441 pgprot_t prot,
442 phys_addr_t (*pgtable_alloc)(int),
443 int flags)
444{
445 mutex_lock(&fixmap_lock);
446 __create_pgd_mapping_locked(pgdir, phys, virt, size, prot,
447 pgtable_alloc, flags);
448 mutex_unlock(lock: &fixmap_lock);
449}
450
451#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
452extern __alias(__create_pgd_mapping_locked)
453void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt,
454 phys_addr_t size, pgprot_t prot,
455 phys_addr_t (*pgtable_alloc)(int), int flags);
456#endif
457
458static phys_addr_t __pgd_pgtable_alloc(int shift)
459{
460 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL);
461 BUG_ON(!ptr);
462
463 /* Ensure the zeroed page is visible to the page table walker */
464 dsb(ishst);
465 return __pa(ptr);
466}
467
468static phys_addr_t pgd_pgtable_alloc(int shift)
469{
470 phys_addr_t pa = __pgd_pgtable_alloc(shift);
471 struct ptdesc *ptdesc = page_ptdesc(phys_to_page(pa));
472
473 /*
474 * Call proper page table ctor in case later we need to
475 * call core mm functions like apply_to_page_range() on
476 * this pre-allocated page table.
477 *
478 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is
479 * folded, and if so pagetable_pte_ctor() becomes nop.
480 */
481 if (shift == PAGE_SHIFT)
482 BUG_ON(!pagetable_pte_ctor(ptdesc));
483 else if (shift == PMD_SHIFT)
484 BUG_ON(!pagetable_pmd_ctor(ptdesc));
485
486 return pa;
487}
488
489/*
490 * This function can only be used to modify existing table entries,
491 * without allocating new levels of table. Note that this permits the
492 * creation of new section or page entries.
493 */
494void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
495 phys_addr_t size, pgprot_t prot)
496{
497 if (virt < PAGE_OFFSET) {
498 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
499 &phys, virt);
500 return;
501 }
502 __create_pgd_mapping(pgdir: init_mm.pgd, phys, virt, size, prot, NULL,
503 NO_CONT_MAPPINGS);
504}
505
506void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
507 unsigned long virt, phys_addr_t size,
508 pgprot_t prot, bool page_mappings_only)
509{
510 int flags = 0;
511
512 BUG_ON(mm == &init_mm);
513
514 if (page_mappings_only)
515 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
516
517 __create_pgd_mapping(pgdir: mm->pgd, phys, virt, size, prot,
518 pgtable_alloc: pgd_pgtable_alloc, flags);
519}
520
521static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
522 phys_addr_t size, pgprot_t prot)
523{
524 if (virt < PAGE_OFFSET) {
525 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n",
526 &phys, virt);
527 return;
528 }
529
530 __create_pgd_mapping(pgdir: init_mm.pgd, phys, virt, size, prot, NULL,
531 NO_CONT_MAPPINGS);
532
533 /* flush the TLBs after updating live kernel mappings */
534 flush_tlb_kernel_range(start: virt, end: virt + size);
535}
536
537static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start,
538 phys_addr_t end, pgprot_t prot, int flags)
539{
540 __create_pgd_mapping(pgdir: pgdp, phys: start, virt: __phys_to_virt(start), size: end - start,
541 prot, pgtable_alloc: early_pgtable_alloc, flags);
542}
543
544void __init mark_linear_text_alias_ro(void)
545{
546 /*
547 * Remove the write permissions from the linear alias of .text/.rodata
548 */
549 update_mapping_prot(__pa_symbol(_stext), virt: (unsigned long)lm_alias(_stext),
550 size: (unsigned long)__init_begin - (unsigned long)_stext,
551 PAGE_KERNEL_RO);
552}
553
554#ifdef CONFIG_KFENCE
555
556bool __ro_after_init kfence_early_init = !!CONFIG_KFENCE_SAMPLE_INTERVAL;
557
558/* early_param() will be parsed before map_mem() below. */
559static int __init parse_kfence_early_init(char *arg)
560{
561 int val;
562
563 if (get_option(str: &arg, pint: &val))
564 kfence_early_init = !!val;
565 return 0;
566}
567early_param("kfence.sample_interval", parse_kfence_early_init);
568
569static phys_addr_t __init arm64_kfence_alloc_pool(void)
570{
571 phys_addr_t kfence_pool;
572
573 if (!kfence_early_init)
574 return 0;
575
576 kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE);
577 if (!kfence_pool) {
578 pr_err("failed to allocate kfence pool\n");
579 kfence_early_init = false;
580 return 0;
581 }
582
583 /* Temporarily mark as NOMAP. */
584 memblock_mark_nomap(base: kfence_pool, KFENCE_POOL_SIZE);
585
586 return kfence_pool;
587}
588
589static void __init arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp)
590{
591 if (!kfence_pool)
592 return;
593
594 /* KFENCE pool needs page-level mapping. */
595 __map_memblock(pgdp, kfence_pool, kfence_pool + KFENCE_POOL_SIZE,
596 pgprot_tagged(PAGE_KERNEL),
597 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
598 memblock_clear_nomap(base: kfence_pool, KFENCE_POOL_SIZE);
599 __kfence_pool = phys_to_virt(address: kfence_pool);
600}
601#else /* CONFIG_KFENCE */
602
603static inline phys_addr_t arm64_kfence_alloc_pool(void) { return 0; }
604static inline void arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) { }
605
606#endif /* CONFIG_KFENCE */
607
608static void __init map_mem(pgd_t *pgdp)
609{
610 static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN);
611 phys_addr_t kernel_start = __pa_symbol(_stext);
612 phys_addr_t kernel_end = __pa_symbol(__init_begin);
613 phys_addr_t start, end;
614 phys_addr_t early_kfence_pool;
615 int flags = NO_EXEC_MAPPINGS;
616 u64 i;
617
618 /*
619 * Setting hierarchical PXNTable attributes on table entries covering
620 * the linear region is only possible if it is guaranteed that no table
621 * entries at any level are being shared between the linear region and
622 * the vmalloc region. Check whether this is true for the PGD level, in
623 * which case it is guaranteed to be true for all other levels as well.
624 * (Unless we are running with support for LPA2, in which case the
625 * entire reduced VA space is covered by a single pgd_t which will have
626 * been populated without the PXNTable attribute by the time we get here.)
627 */
628 BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end) &&
629 pgd_index(_PAGE_OFFSET(VA_BITS_MIN)) != PTRS_PER_PGD - 1);
630
631 early_kfence_pool = arm64_kfence_alloc_pool();
632
633 if (can_set_direct_map())
634 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
635
636 /*
637 * Take care not to create a writable alias for the
638 * read-only text and rodata sections of the kernel image.
639 * So temporarily mark them as NOMAP to skip mappings in
640 * the following for-loop
641 */
642 memblock_mark_nomap(base: kernel_start, size: kernel_end - kernel_start);
643
644 /* map all the memory banks */
645 for_each_mem_range(i, &start, &end) {
646 if (start >= end)
647 break;
648 /*
649 * The linear map must allow allocation tags reading/writing
650 * if MTE is present. Otherwise, it has the same attributes as
651 * PAGE_KERNEL.
652 */
653 __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL),
654 flags);
655 }
656
657 /*
658 * Map the linear alias of the [_stext, __init_begin) interval
659 * as non-executable now, and remove the write permission in
660 * mark_linear_text_alias_ro() below (which will be called after
661 * alternative patching has completed). This makes the contents
662 * of the region accessible to subsystems such as hibernate,
663 * but protects it from inadvertent modification or execution.
664 * Note that contiguous mappings cannot be remapped in this way,
665 * so we should avoid them here.
666 */
667 __map_memblock(pgdp, start: kernel_start, end: kernel_end,
668 PAGE_KERNEL, NO_CONT_MAPPINGS);
669 memblock_clear_nomap(base: kernel_start, size: kernel_end - kernel_start);
670 arm64_kfence_map_pool(kfence_pool: early_kfence_pool, pgdp);
671}
672
673void mark_rodata_ro(void)
674{
675 unsigned long section_size;
676
677 /*
678 * mark .rodata as read only. Use __init_begin rather than __end_rodata
679 * to cover NOTES and EXCEPTION_TABLE.
680 */
681 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
682 WRITE_ONCE(rodata_is_rw, false);
683 update_mapping_prot(__pa_symbol(__start_rodata), virt: (unsigned long)__start_rodata,
684 size: section_size, PAGE_KERNEL_RO);
685}
686
687static void __init declare_vma(struct vm_struct *vma,
688 void *va_start, void *va_end,
689 unsigned long vm_flags)
690{
691 phys_addr_t pa_start = __pa_symbol(va_start);
692 unsigned long size = va_end - va_start;
693
694 BUG_ON(!PAGE_ALIGNED(pa_start));
695 BUG_ON(!PAGE_ALIGNED(size));
696
697 if (!(vm_flags & VM_NO_GUARD))
698 size += PAGE_SIZE;
699
700 vma->addr = va_start;
701 vma->phys_addr = pa_start;
702 vma->size = size;
703 vma->flags = VM_MAP | vm_flags;
704 vma->caller = __builtin_return_address(0);
705
706 vm_area_add_early(vm: vma);
707}
708
709#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
710static pgprot_t kernel_exec_prot(void)
711{
712 return rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
713}
714
715static int __init map_entry_trampoline(void)
716{
717 int i;
718
719 if (!arm64_kernel_unmapped_at_el0())
720 return 0;
721
722 pgprot_t prot = kernel_exec_prot();
723 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
724
725 /* The trampoline is always mapped and can therefore be global */
726 pgprot_val(prot) &= ~PTE_NG;
727
728 /* Map only the text into the trampoline page table */
729 memset(tramp_pg_dir, 0, PGD_SIZE);
730 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS,
731 entry_tramp_text_size(), prot,
732 __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS);
733
734 /* Map both the text and data into the kernel page table */
735 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++)
736 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i,
737 pa_start + i * PAGE_SIZE, prot);
738
739 if (IS_ENABLED(CONFIG_RELOCATABLE))
740 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i,
741 pa_start + i * PAGE_SIZE, PAGE_KERNEL_RO);
742
743 return 0;
744}
745core_initcall(map_entry_trampoline);
746#endif
747
748/*
749 * Declare the VMA areas for the kernel
750 */
751static void __init declare_kernel_vmas(void)
752{
753 static struct vm_struct vmlinux_seg[KERNEL_SEGMENT_COUNT];
754
755 declare_vma(vma: &vmlinux_seg[0], va_start: _stext, va_end: _etext, VM_NO_GUARD);
756 declare_vma(&vmlinux_seg[1], __start_rodata, __inittext_begin, VM_NO_GUARD);
757 declare_vma(&vmlinux_seg[2], __inittext_begin, __inittext_end, VM_NO_GUARD);
758 declare_vma(&vmlinux_seg[3], __initdata_begin, __initdata_end, VM_NO_GUARD);
759 declare_vma(vma: &vmlinux_seg[4], va_start: _data, va_end: _end, vm_flags: 0);
760}
761
762void __pi_map_range(u64 *pgd, u64 start, u64 end, u64 pa, pgprot_t prot,
763 int level, pte_t *tbl, bool may_use_cont, u64 va_offset);
764
765static u8 idmap_ptes[IDMAP_LEVELS - 1][PAGE_SIZE] __aligned(PAGE_SIZE) __ro_after_init,
766 kpti_ptes[IDMAP_LEVELS - 1][PAGE_SIZE] __aligned(PAGE_SIZE) __ro_after_init;
767
768static void __init create_idmap(void)
769{
770 u64 start = __pa_symbol(__idmap_text_start);
771 u64 end = __pa_symbol(__idmap_text_end);
772 u64 ptep = __pa_symbol(idmap_ptes);
773
774 __pi_map_range(&ptep, start, end, start, PAGE_KERNEL_ROX,
775 IDMAP_ROOT_LEVEL, (pte_t *)idmap_pg_dir, false,
776 __phys_to_virt(ptep) - ptep);
777
778 if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0) && !arm64_use_ng_mappings) {
779 extern u32 __idmap_kpti_flag;
780 u64 pa = __pa_symbol(&__idmap_kpti_flag);
781
782 /*
783 * The KPTI G-to-nG conversion code needs a read-write mapping
784 * of its synchronization flag in the ID map.
785 */
786 ptep = __pa_symbol(kpti_ptes);
787 __pi_map_range(&ptep, pa, pa + sizeof(u32), pa, PAGE_KERNEL,
788 IDMAP_ROOT_LEVEL, (pte_t *)idmap_pg_dir, false,
789 __phys_to_virt(ptep) - ptep);
790 }
791}
792
793void __init paging_init(void)
794{
795 map_mem(swapper_pg_dir);
796
797 memblock_allow_resize();
798
799 create_idmap();
800 declare_kernel_vmas();
801}
802
803#ifdef CONFIG_MEMORY_HOTPLUG
804static void free_hotplug_page_range(struct page *page, size_t size,
805 struct vmem_altmap *altmap)
806{
807 if (altmap) {
808 vmem_altmap_free(altmap, nr_pfns: size >> PAGE_SHIFT);
809 } else {
810 WARN_ON(PageReserved(page));
811 free_pages(addr: (unsigned long)page_address(page), order: get_order(size));
812 }
813}
814
815static void free_hotplug_pgtable_page(struct page *page)
816{
817 free_hotplug_page_range(page, PAGE_SIZE, NULL);
818}
819
820static bool pgtable_range_aligned(unsigned long start, unsigned long end,
821 unsigned long floor, unsigned long ceiling,
822 unsigned long mask)
823{
824 start &= mask;
825 if (start < floor)
826 return false;
827
828 if (ceiling) {
829 ceiling &= mask;
830 if (!ceiling)
831 return false;
832 }
833
834 if (end - 1 > ceiling - 1)
835 return false;
836 return true;
837}
838
839static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr,
840 unsigned long end, bool free_mapped,
841 struct vmem_altmap *altmap)
842{
843 pte_t *ptep, pte;
844
845 do {
846 ptep = pte_offset_kernel(pmd: pmdp, address: addr);
847 pte = __ptep_get(ptep);
848 if (pte_none(pte))
849 continue;
850
851 WARN_ON(!pte_present(pte));
852 __pte_clear(&init_mm, addr, ptep);
853 flush_tlb_kernel_range(start: addr, end: addr + PAGE_SIZE);
854 if (free_mapped)
855 free_hotplug_page_range(pte_page(pte),
856 PAGE_SIZE, altmap);
857 } while (addr += PAGE_SIZE, addr < end);
858}
859
860static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr,
861 unsigned long end, bool free_mapped,
862 struct vmem_altmap *altmap)
863{
864 unsigned long next;
865 pmd_t *pmdp, pmd;
866
867 do {
868 next = pmd_addr_end(addr, end);
869 pmdp = pmd_offset(pud: pudp, address: addr);
870 pmd = READ_ONCE(*pmdp);
871 if (pmd_none(pmd))
872 continue;
873
874 WARN_ON(!pmd_present(pmd));
875 if (pmd_sect(pmd)) {
876 pmd_clear(pmdp);
877
878 /*
879 * One TLBI should be sufficient here as the PMD_SIZE
880 * range is mapped with a single block entry.
881 */
882 flush_tlb_kernel_range(start: addr, end: addr + PAGE_SIZE);
883 if (free_mapped)
884 free_hotplug_page_range(pmd_page(pmd),
885 PMD_SIZE, altmap);
886 continue;
887 }
888 WARN_ON(!pmd_table(pmd));
889 unmap_hotplug_pte_range(pmdp, addr, end: next, free_mapped, altmap);
890 } while (addr = next, addr < end);
891}
892
893static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr,
894 unsigned long end, bool free_mapped,
895 struct vmem_altmap *altmap)
896{
897 unsigned long next;
898 pud_t *pudp, pud;
899
900 do {
901 next = pud_addr_end(addr, end);
902 pudp = pud_offset(p4d: p4dp, address: addr);
903 pud = READ_ONCE(*pudp);
904 if (pud_none(pud))
905 continue;
906
907 WARN_ON(!pud_present(pud));
908 if (pud_sect(pud)) {
909 pud_clear(pudp);
910
911 /*
912 * One TLBI should be sufficient here as the PUD_SIZE
913 * range is mapped with a single block entry.
914 */
915 flush_tlb_kernel_range(start: addr, end: addr + PAGE_SIZE);
916 if (free_mapped)
917 free_hotplug_page_range(pud_page(pud),
918 PUD_SIZE, altmap);
919 continue;
920 }
921 WARN_ON(!pud_table(pud));
922 unmap_hotplug_pmd_range(pudp, addr, end: next, free_mapped, altmap);
923 } while (addr = next, addr < end);
924}
925
926static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr,
927 unsigned long end, bool free_mapped,
928 struct vmem_altmap *altmap)
929{
930 unsigned long next;
931 p4d_t *p4dp, p4d;
932
933 do {
934 next = p4d_addr_end(addr, end);
935 p4dp = p4d_offset(pgd: pgdp, address: addr);
936 p4d = READ_ONCE(*p4dp);
937 if (p4d_none(p4d))
938 continue;
939
940 WARN_ON(!p4d_present(p4d));
941 unmap_hotplug_pud_range(p4dp, addr, end: next, free_mapped, altmap);
942 } while (addr = next, addr < end);
943}
944
945static void unmap_hotplug_range(unsigned long addr, unsigned long end,
946 bool free_mapped, struct vmem_altmap *altmap)
947{
948 unsigned long next;
949 pgd_t *pgdp, pgd;
950
951 /*
952 * altmap can only be used as vmemmap mapping backing memory.
953 * In case the backing memory itself is not being freed, then
954 * altmap is irrelevant. Warn about this inconsistency when
955 * encountered.
956 */
957 WARN_ON(!free_mapped && altmap);
958
959 do {
960 next = pgd_addr_end(addr, end);
961 pgdp = pgd_offset_k(addr);
962 pgd = READ_ONCE(*pgdp);
963 if (pgd_none(pgd))
964 continue;
965
966 WARN_ON(!pgd_present(pgd));
967 unmap_hotplug_p4d_range(pgdp, addr, end: next, free_mapped, altmap);
968 } while (addr = next, addr < end);
969}
970
971static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr,
972 unsigned long end, unsigned long floor,
973 unsigned long ceiling)
974{
975 pte_t *ptep, pte;
976 unsigned long i, start = addr;
977
978 do {
979 ptep = pte_offset_kernel(pmd: pmdp, address: addr);
980 pte = __ptep_get(ptep);
981
982 /*
983 * This is just a sanity check here which verifies that
984 * pte clearing has been done by earlier unmap loops.
985 */
986 WARN_ON(!pte_none(pte));
987 } while (addr += PAGE_SIZE, addr < end);
988
989 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK))
990 return;
991
992 /*
993 * Check whether we can free the pte page if the rest of the
994 * entries are empty. Overlap with other regions have been
995 * handled by the floor/ceiling check.
996 */
997 ptep = pte_offset_kernel(pmd: pmdp, address: 0UL);
998 for (i = 0; i < PTRS_PER_PTE; i++) {
999 if (!pte_none(__ptep_get(&ptep[i])))
1000 return;
1001 }
1002
1003 pmd_clear(pmdp);
1004 __flush_tlb_kernel_pgtable(start);
1005 free_hotplug_pgtable_page(virt_to_page(ptep));
1006}
1007
1008static void free_empty_pmd_table(pud_t *pudp, unsigned long addr,
1009 unsigned long end, unsigned long floor,
1010 unsigned long ceiling)
1011{
1012 pmd_t *pmdp, pmd;
1013 unsigned long i, next, start = addr;
1014
1015 do {
1016 next = pmd_addr_end(addr, end);
1017 pmdp = pmd_offset(pud: pudp, address: addr);
1018 pmd = READ_ONCE(*pmdp);
1019 if (pmd_none(pmd))
1020 continue;
1021
1022 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd));
1023 free_empty_pte_table(pmdp, addr, end: next, floor, ceiling);
1024 } while (addr = next, addr < end);
1025
1026 if (CONFIG_PGTABLE_LEVELS <= 2)
1027 return;
1028
1029 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK))
1030 return;
1031
1032 /*
1033 * Check whether we can free the pmd page if the rest of the
1034 * entries are empty. Overlap with other regions have been
1035 * handled by the floor/ceiling check.
1036 */
1037 pmdp = pmd_offset(pud: pudp, address: 0UL);
1038 for (i = 0; i < PTRS_PER_PMD; i++) {
1039 if (!pmd_none(READ_ONCE(pmdp[i])))
1040 return;
1041 }
1042
1043 pud_clear(pudp);
1044 __flush_tlb_kernel_pgtable(start);
1045 free_hotplug_pgtable_page(virt_to_page(pmdp));
1046}
1047
1048static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr,
1049 unsigned long end, unsigned long floor,
1050 unsigned long ceiling)
1051{
1052 pud_t *pudp, pud;
1053 unsigned long i, next, start = addr;
1054
1055 do {
1056 next = pud_addr_end(addr, end);
1057 pudp = pud_offset(p4d: p4dp, address: addr);
1058 pud = READ_ONCE(*pudp);
1059 if (pud_none(pud))
1060 continue;
1061
1062 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud));
1063 free_empty_pmd_table(pudp, addr, end: next, floor, ceiling);
1064 } while (addr = next, addr < end);
1065
1066 if (!pgtable_l4_enabled())
1067 return;
1068
1069 if (!pgtable_range_aligned(start, end, floor, ceiling, P4D_MASK))
1070 return;
1071
1072 /*
1073 * Check whether we can free the pud page if the rest of the
1074 * entries are empty. Overlap with other regions have been
1075 * handled by the floor/ceiling check.
1076 */
1077 pudp = pud_offset(p4d: p4dp, address: 0UL);
1078 for (i = 0; i < PTRS_PER_PUD; i++) {
1079 if (!pud_none(READ_ONCE(pudp[i])))
1080 return;
1081 }
1082
1083 p4d_clear(p4dp);
1084 __flush_tlb_kernel_pgtable(start);
1085 free_hotplug_pgtable_page(virt_to_page(pudp));
1086}
1087
1088static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr,
1089 unsigned long end, unsigned long floor,
1090 unsigned long ceiling)
1091{
1092 p4d_t *p4dp, p4d;
1093 unsigned long i, next, start = addr;
1094
1095 do {
1096 next = p4d_addr_end(addr, end);
1097 p4dp = p4d_offset(pgd: pgdp, address: addr);
1098 p4d = READ_ONCE(*p4dp);
1099 if (p4d_none(p4d))
1100 continue;
1101
1102 WARN_ON(!p4d_present(p4d));
1103 free_empty_pud_table(p4dp, addr, end: next, floor, ceiling);
1104 } while (addr = next, addr < end);
1105
1106 if (!pgtable_l5_enabled())
1107 return;
1108
1109 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK))
1110 return;
1111
1112 /*
1113 * Check whether we can free the p4d page if the rest of the
1114 * entries are empty. Overlap with other regions have been
1115 * handled by the floor/ceiling check.
1116 */
1117 p4dp = p4d_offset(pgd: pgdp, address: 0UL);
1118 for (i = 0; i < PTRS_PER_P4D; i++) {
1119 if (!p4d_none(READ_ONCE(p4dp[i])))
1120 return;
1121 }
1122
1123 pgd_clear(pgdp);
1124 __flush_tlb_kernel_pgtable(start);
1125 free_hotplug_pgtable_page(virt_to_page(p4dp));
1126}
1127
1128static void free_empty_tables(unsigned long addr, unsigned long end,
1129 unsigned long floor, unsigned long ceiling)
1130{
1131 unsigned long next;
1132 pgd_t *pgdp, pgd;
1133
1134 do {
1135 next = pgd_addr_end(addr, end);
1136 pgdp = pgd_offset_k(addr);
1137 pgd = READ_ONCE(*pgdp);
1138 if (pgd_none(pgd))
1139 continue;
1140
1141 WARN_ON(!pgd_present(pgd));
1142 free_empty_p4d_table(pgdp, addr, end: next, floor, ceiling);
1143 } while (addr = next, addr < end);
1144}
1145#endif
1146
1147void __meminit vmemmap_set_pmd(pmd_t *pmdp, void *p, int node,
1148 unsigned long addr, unsigned long next)
1149{
1150 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL));
1151}
1152
1153int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node,
1154 unsigned long addr, unsigned long next)
1155{
1156 vmemmap_verify((pte_t *)pmdp, node, addr, next);
1157 return 1;
1158}
1159
1160int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
1161 struct vmem_altmap *altmap)
1162{
1163 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));
1164
1165 if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES))
1166 return vmemmap_populate_basepages(start, end, node, altmap);
1167 else
1168 return vmemmap_populate_hugepages(start, end, node, altmap);
1169}
1170
1171#ifdef CONFIG_MEMORY_HOTPLUG
1172void vmemmap_free(unsigned long start, unsigned long end,
1173 struct vmem_altmap *altmap)
1174{
1175 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));
1176
1177 unmap_hotplug_range(addr: start, end, free_mapped: true, altmap);
1178 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END);
1179}
1180#endif /* CONFIG_MEMORY_HOTPLUG */
1181
1182int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
1183{
1184 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));
1185
1186 /* Only allow permission changes for now */
1187 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)),
1188 new: pud_val(pud: new_pud)))
1189 return 0;
1190
1191 VM_BUG_ON(phys & ~PUD_MASK);
1192 set_pud(pudp, pud: new_pud);
1193 return 1;
1194}
1195
1196int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
1197{
1198 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot));
1199
1200 /* Only allow permission changes for now */
1201 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)),
1202 new: pmd_val(pmd: new_pmd)))
1203 return 0;
1204
1205 VM_BUG_ON(phys & ~PMD_MASK);
1206 set_pmd(pmdp, pmd: new_pmd);
1207 return 1;
1208}
1209
1210#ifndef __PAGETABLE_P4D_FOLDED
1211void p4d_clear_huge(p4d_t *p4dp)
1212{
1213}
1214#endif
1215
1216int pud_clear_huge(pud_t *pudp)
1217{
1218 if (!pud_sect(READ_ONCE(*pudp)))
1219 return 0;
1220 pud_clear(pudp);
1221 return 1;
1222}
1223
1224int pmd_clear_huge(pmd_t *pmdp)
1225{
1226 if (!pmd_sect(READ_ONCE(*pmdp)))
1227 return 0;
1228 pmd_clear(pmdp);
1229 return 1;
1230}
1231
1232int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr)
1233{
1234 pte_t *table;
1235 pmd_t pmd;
1236
1237 pmd = READ_ONCE(*pmdp);
1238
1239 if (!pmd_table(pmd)) {
1240 VM_WARN_ON(1);
1241 return 1;
1242 }
1243
1244 table = pte_offset_kernel(pmd: pmdp, address: addr);
1245 pmd_clear(pmdp);
1246 __flush_tlb_kernel_pgtable(addr);
1247 pte_free_kernel(NULL, pte: table);
1248 return 1;
1249}
1250
1251int pud_free_pmd_page(pud_t *pudp, unsigned long addr)
1252{
1253 pmd_t *table;
1254 pmd_t *pmdp;
1255 pud_t pud;
1256 unsigned long next, end;
1257
1258 pud = READ_ONCE(*pudp);
1259
1260 if (!pud_table(pud)) {
1261 VM_WARN_ON(1);
1262 return 1;
1263 }
1264
1265 table = pmd_offset(pud: pudp, address: addr);
1266 pmdp = table;
1267 next = addr;
1268 end = addr + PUD_SIZE;
1269 do {
1270 pmd_free_pte_page(pmdp, addr: next);
1271 } while (pmdp++, next += PMD_SIZE, next != end);
1272
1273 pud_clear(pudp);
1274 __flush_tlb_kernel_pgtable(addr);
1275 pmd_free(NULL, pmd: table);
1276 return 1;
1277}
1278
1279#ifdef CONFIG_MEMORY_HOTPLUG
1280static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size)
1281{
1282 unsigned long end = start + size;
1283
1284 WARN_ON(pgdir != init_mm.pgd);
1285 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END));
1286
1287 unmap_hotplug_range(addr: start, end, free_mapped: false, NULL);
1288 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END);
1289}
1290
1291struct range arch_get_mappable_range(void)
1292{
1293 struct range mhp_range;
1294 u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual));
1295 u64 end_linear_pa = __pa(PAGE_END - 1);
1296
1297 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
1298 /*
1299 * Check for a wrap, it is possible because of randomized linear
1300 * mapping the start physical address is actually bigger than
1301 * the end physical address. In this case set start to zero
1302 * because [0, end_linear_pa] range must still be able to cover
1303 * all addressable physical addresses.
1304 */
1305 if (start_linear_pa > end_linear_pa)
1306 start_linear_pa = 0;
1307 }
1308
1309 WARN_ON(start_linear_pa > end_linear_pa);
1310
1311 /*
1312 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)]
1313 * accommodating both its ends but excluding PAGE_END. Max physical
1314 * range which can be mapped inside this linear mapping range, must
1315 * also be derived from its end points.
1316 */
1317 mhp_range.start = start_linear_pa;
1318 mhp_range.end = end_linear_pa;
1319
1320 return mhp_range;
1321}
1322
1323int arch_add_memory(int nid, u64 start, u64 size,
1324 struct mhp_params *params)
1325{
1326 int ret, flags = NO_EXEC_MAPPINGS;
1327
1328 VM_BUG_ON(!mhp_range_allowed(start, size, true));
1329
1330 if (can_set_direct_map())
1331 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
1332
1333 __create_pgd_mapping(swapper_pg_dir, phys: start, virt: __phys_to_virt(start),
1334 size, prot: params->pgprot, pgtable_alloc: __pgd_pgtable_alloc,
1335 flags);
1336
1337 memblock_clear_nomap(base: start, size);
1338
1339 ret = __add_pages(nid, start_pfn: start >> PAGE_SHIFT, nr_pages: size >> PAGE_SHIFT,
1340 params);
1341 if (ret)
1342 __remove_pgd_mapping(swapper_pg_dir,
1343 start: __phys_to_virt(start), size);
1344 else {
1345 max_pfn = PFN_UP(start + size);
1346 max_low_pfn = max_pfn;
1347 }
1348
1349 return ret;
1350}
1351
1352void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
1353{
1354 unsigned long start_pfn = start >> PAGE_SHIFT;
1355 unsigned long nr_pages = size >> PAGE_SHIFT;
1356
1357 __remove_pages(start_pfn, nr_pages, altmap);
1358 __remove_pgd_mapping(swapper_pg_dir, start: __phys_to_virt(start), size);
1359}
1360
1361/*
1362 * This memory hotplug notifier helps prevent boot memory from being
1363 * inadvertently removed as it blocks pfn range offlining process in
1364 * __offline_pages(). Hence this prevents both offlining as well as
1365 * removal process for boot memory which is initially always online.
1366 * In future if and when boot memory could be removed, this notifier
1367 * should be dropped and free_hotplug_page_range() should handle any
1368 * reserved pages allocated during boot.
1369 */
1370static int prevent_bootmem_remove_notifier(struct notifier_block *nb,
1371 unsigned long action, void *data)
1372{
1373 struct mem_section *ms;
1374 struct memory_notify *arg = data;
1375 unsigned long end_pfn = arg->start_pfn + arg->nr_pages;
1376 unsigned long pfn = arg->start_pfn;
1377
1378 if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE))
1379 return NOTIFY_OK;
1380
1381 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1382 unsigned long start = PFN_PHYS(pfn);
1383 unsigned long end = start + (1UL << PA_SECTION_SHIFT);
1384
1385 ms = __pfn_to_section(pfn);
1386 if (!early_section(section: ms))
1387 continue;
1388
1389 if (action == MEM_GOING_OFFLINE) {
1390 /*
1391 * Boot memory removal is not supported. Prevent
1392 * it via blocking any attempted offline request
1393 * for the boot memory and just report it.
1394 */
1395 pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end);
1396 return NOTIFY_BAD;
1397 } else if (action == MEM_OFFLINE) {
1398 /*
1399 * This should have never happened. Boot memory
1400 * offlining should have been prevented by this
1401 * very notifier. Probably some memory removal
1402 * procedure might have changed which would then
1403 * require further debug.
1404 */
1405 pr_err("Boot memory [%lx %lx] offlined\n", start, end);
1406
1407 /*
1408 * Core memory hotplug does not process a return
1409 * code from the notifier for MEM_OFFLINE events.
1410 * The error condition has been reported. Return
1411 * from here as if ignored.
1412 */
1413 return NOTIFY_DONE;
1414 }
1415 }
1416 return NOTIFY_OK;
1417}
1418
1419static struct notifier_block prevent_bootmem_remove_nb = {
1420 .notifier_call = prevent_bootmem_remove_notifier,
1421};
1422
1423/*
1424 * This ensures that boot memory sections on the platform are online
1425 * from early boot. Memory sections could not be prevented from being
1426 * offlined, unless for some reason they are not online to begin with.
1427 * This helps validate the basic assumption on which the above memory
1428 * event notifier works to prevent boot memory section offlining and
1429 * its possible removal.
1430 */
1431static void validate_bootmem_online(void)
1432{
1433 phys_addr_t start, end, addr;
1434 struct mem_section *ms;
1435 u64 i;
1436
1437 /*
1438 * Scanning across all memblock might be expensive
1439 * on some big memory systems. Hence enable this
1440 * validation only with DEBUG_VM.
1441 */
1442 if (!IS_ENABLED(CONFIG_DEBUG_VM))
1443 return;
1444
1445 for_each_mem_range(i, &start, &end) {
1446 for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) {
1447 ms = __pfn_to_section(PHYS_PFN(addr));
1448
1449 /*
1450 * All memory ranges in the system at this point
1451 * should have been marked as early sections.
1452 */
1453 WARN_ON(!early_section(ms));
1454
1455 /*
1456 * Memory notifier mechanism here to prevent boot
1457 * memory offlining depends on the fact that each
1458 * early section memory on the system is initially
1459 * online. Otherwise a given memory section which
1460 * is already offline will be overlooked and can
1461 * be removed completely. Call out such sections.
1462 */
1463 if (!online_section(section: ms))
1464 pr_err("Boot memory [%llx %llx] is offline, can be removed\n",
1465 addr, addr + (1UL << PA_SECTION_SHIFT));
1466 }
1467 }
1468}
1469
1470static int __init prevent_bootmem_remove_init(void)
1471{
1472 int ret = 0;
1473
1474 if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
1475 return ret;
1476
1477 validate_bootmem_online();
1478 ret = register_memory_notifier(nb: &prevent_bootmem_remove_nb);
1479 if (ret)
1480 pr_err("%s: Notifier registration failed %d\n", __func__, ret);
1481
1482 return ret;
1483}
1484early_initcall(prevent_bootmem_remove_init);
1485#endif
1486
1487pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
1488{
1489 if (alternative_has_cap_unlikely(ARM64_WORKAROUND_2645198)) {
1490 /*
1491 * Break-before-make (BBM) is required for all user space mappings
1492 * when the permission changes from executable to non-executable
1493 * in cases where cpu is affected with errata #2645198.
1494 */
1495 if (pte_user_exec(ptep_get(ptep)))
1496 return ptep_clear_flush(vma, address: addr, ptep);
1497 }
1498 return ptep_get_and_clear(mm: vma->vm_mm, addr, ptep);
1499}
1500
1501void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep,
1502 pte_t old_pte, pte_t pte)
1503{
1504 set_pte_at(vma->vm_mm, addr, ptep, pte);
1505}
1506
1507/*
1508 * Atomically replaces the active TTBR1_EL1 PGD with a new VA-compatible PGD,
1509 * avoiding the possibility of conflicting TLB entries being allocated.
1510 */
1511void __cpu_replace_ttbr1(pgd_t *pgdp, bool cnp)
1512{
1513 typedef void (ttbr_replace_func)(phys_addr_t);
1514 extern ttbr_replace_func idmap_cpu_replace_ttbr1;
1515 ttbr_replace_func *replace_phys;
1516 unsigned long daif;
1517
1518 /* phys_to_ttbr() zeros lower 2 bits of ttbr with 52-bit PA */
1519 phys_addr_t ttbr1 = phys_to_ttbr(virt_to_phys(address: pgdp));
1520
1521 if (cnp)
1522 ttbr1 |= TTBR_CNP_BIT;
1523
1524 replace_phys = (void *)__pa_symbol(idmap_cpu_replace_ttbr1);
1525
1526 cpu_install_idmap();
1527
1528 /*
1529 * We really don't want to take *any* exceptions while TTBR1 is
1530 * in the process of being replaced so mask everything.
1531 */
1532 daif = local_daif_save();
1533 replace_phys(ttbr1);
1534 local_daif_restore(daif);
1535
1536 cpu_uninstall_idmap();
1537}
1538

source code of linux/arch/arm64/mm/mmu.c