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
48	u64 kimage_voffset __ro_after_init;
49	EXPORT_SYMBOL(kimage_voffset);
50
51	u32 __boot_cpu_mode[] = { BOOT_CPU_MODE_EL2, BOOT_CPU_MODE_EL1 };
52
53	static 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	*/
59	long __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	*/
65	unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
66	EXPORT_SYMBOL(empty_zero_page);
67
68	static DEFINE_SPINLOCK(swapper_pgdir_lock);
69	static DEFINE_MUTEX(fixmap_lock);
70
71	void 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
98	pgprot_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	}
107	EXPORT_SYMBOL(phys_mem_access_prot);
108
109	static 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
137	bool 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
175	static 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
199	static 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
238	static 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
275	static 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
316	static 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
371	static 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
411	static 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
439	static 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
452	extern __alias(__create_pgd_mapping_locked)
453	void 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
458	static 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
468	static 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	*/
494	void __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
506	void __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
521	static 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
537	static 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
544	void __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
556	bool __ro_after_init kfence_early_init = !!CONFIG_KFENCE_SAMPLE_INTERVAL;
557
558	/* early_param() will be parsed before map_mem() below. */
559	static 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	}
567	early_param("kfence.sample_interval", parse_kfence_early_init);
568
569	static 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
589	static 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
603	static inline phys_addr_t arm64_kfence_alloc_pool(void) { return 0; }
604	static inline void arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) { }
605
606	#endif /* CONFIG_KFENCE */
607
608	static 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
673	void 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
687	static 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
710	static pgprot_t kernel_exec_prot(void)
711	{
712	return rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
713	}
714
715	static 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	}
745	core_initcall(map_entry_trampoline);
746	#endif
747
748	/*
749	* Declare the VMA areas for the kernel
750	*/
751	static 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
762	void __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
765	static 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
768	static 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
793	void __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
804	static 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
815	static void free_hotplug_pgtable_page(struct page *page)
816	{
817	free_hotplug_page_range(page, PAGE_SIZE, NULL);
818	}
819
820	static 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
839	static 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
860	static 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
893	static 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
926	static 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
945	static 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
971	static 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
1008	static 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
1048	static 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
1088	static 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
1128	static 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
1147	void __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
1153	int __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
1160	int __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
1172	void 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
1182	int 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
1196	int 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
1211	void p4d_clear_huge(p4d_t *p4dp)
1212	{
1213	}
1214	#endif
1215
1216	int 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
1224	int 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
1232	int 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
1251	int 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
1280	static 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
1291	struct 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
1323	int 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
1352	void 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	*/
1370	static 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
1419	static 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	*/
1431	static 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
1470	static 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	}
1484	early_initcall(prevent_bootmem_remove_init);
1485	#endif
1486
1487	pte_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
1501	void 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	*/
1511	void __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