1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *    Copyright IBM Corp. 2006
4  */
5 
6 #include <linux/memory_hotplug.h>
7 #include <linux/memblock.h>
8 #include <linux/pfn.h>
9 #include <linux/mm.h>
10 #include <linux/init.h>
11 #include <linux/list.h>
12 #include <linux/hugetlb.h>
13 #include <linux/slab.h>
14 #include <linux/sort.h>
15 #include <asm/page-states.h>
16 #include <asm/cacheflush.h>
17 #include <asm/nospec-branch.h>
18 #include <asm/pgalloc.h>
19 #include <asm/setup.h>
20 #include <asm/tlbflush.h>
21 #include <asm/sections.h>
22 #include <asm/set_memory.h>
23 
24 static DEFINE_MUTEX(vmem_mutex);
25 
vmem_alloc_pages(unsigned int order)26 static void __ref *vmem_alloc_pages(unsigned int order)
27 {
28 	unsigned long size = PAGE_SIZE << order;
29 
30 	if (slab_is_available())
31 		return (void *)__get_free_pages(GFP_KERNEL, order);
32 	return memblock_alloc(size, size);
33 }
34 
vmem_free_pages(unsigned long addr,int order)35 static void vmem_free_pages(unsigned long addr, int order)
36 {
37 	/* We don't expect boot memory to be removed ever. */
38 	if (!slab_is_available() ||
39 	    WARN_ON_ONCE(PageReserved(virt_to_page((void *)addr))))
40 		return;
41 	free_pages(addr, order);
42 }
43 
vmem_crst_alloc(unsigned long val)44 void *vmem_crst_alloc(unsigned long val)
45 {
46 	unsigned long *table;
47 
48 	table = vmem_alloc_pages(CRST_ALLOC_ORDER);
49 	if (!table)
50 		return NULL;
51 	crst_table_init(table, val);
52 	if (slab_is_available())
53 		arch_set_page_dat(virt_to_page(table), CRST_ALLOC_ORDER);
54 	return table;
55 }
56 
vmem_pte_alloc(void)57 pte_t __ref *vmem_pte_alloc(void)
58 {
59 	unsigned long size = PTRS_PER_PTE * sizeof(pte_t);
60 	pte_t *pte;
61 
62 	if (slab_is_available())
63 		pte = (pte_t *) page_table_alloc(&init_mm);
64 	else
65 		pte = (pte_t *) memblock_alloc(size, size);
66 	if (!pte)
67 		return NULL;
68 	memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
69 	return pte;
70 }
71 
vmem_pte_free(unsigned long * table)72 static void vmem_pte_free(unsigned long *table)
73 {
74 	/* We don't expect boot memory to be removed ever. */
75 	if (!slab_is_available() ||
76 	    WARN_ON_ONCE(PageReserved(virt_to_page(table))))
77 		return;
78 	page_table_free(&init_mm, table);
79 }
80 
81 #define PAGE_UNUSED 0xFD
82 
83 /*
84  * The unused vmemmap range, which was not yet memset(PAGE_UNUSED) ranges
85  * from unused_sub_pmd_start to next PMD_SIZE boundary.
86  */
87 static unsigned long unused_sub_pmd_start;
88 
vmemmap_flush_unused_sub_pmd(void)89 static void vmemmap_flush_unused_sub_pmd(void)
90 {
91 	if (!unused_sub_pmd_start)
92 		return;
93 	memset((void *)unused_sub_pmd_start, PAGE_UNUSED,
94 	       ALIGN(unused_sub_pmd_start, PMD_SIZE) - unused_sub_pmd_start);
95 	unused_sub_pmd_start = 0;
96 }
97 
vmemmap_mark_sub_pmd_used(unsigned long start,unsigned long end)98 static void vmemmap_mark_sub_pmd_used(unsigned long start, unsigned long end)
99 {
100 	/*
101 	 * As we expect to add in the same granularity as we remove, it's
102 	 * sufficient to mark only some piece used to block the memmap page from
103 	 * getting removed (just in case the memmap never gets initialized,
104 	 * e.g., because the memory block never gets onlined).
105 	 */
106 	memset((void *)start, 0, sizeof(struct page));
107 }
108 
vmemmap_use_sub_pmd(unsigned long start,unsigned long end)109 static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end)
110 {
111 	/*
112 	 * We only optimize if the new used range directly follows the
113 	 * previously unused range (esp., when populating consecutive sections).
114 	 */
115 	if (unused_sub_pmd_start == start) {
116 		unused_sub_pmd_start = end;
117 		if (likely(IS_ALIGNED(unused_sub_pmd_start, PMD_SIZE)))
118 			unused_sub_pmd_start = 0;
119 		return;
120 	}
121 	vmemmap_flush_unused_sub_pmd();
122 	vmemmap_mark_sub_pmd_used(start, end);
123 }
124 
vmemmap_use_new_sub_pmd(unsigned long start,unsigned long end)125 static void vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end)
126 {
127 	unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
128 
129 	vmemmap_flush_unused_sub_pmd();
130 
131 	/* Could be our memmap page is filled with PAGE_UNUSED already ... */
132 	vmemmap_mark_sub_pmd_used(start, end);
133 
134 	/* Mark the unused parts of the new memmap page PAGE_UNUSED. */
135 	if (!IS_ALIGNED(start, PMD_SIZE))
136 		memset((void *)page, PAGE_UNUSED, start - page);
137 	/*
138 	 * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of
139 	 * consecutive sections. Remember for the last added PMD the last
140 	 * unused range in the populated PMD.
141 	 */
142 	if (!IS_ALIGNED(end, PMD_SIZE))
143 		unused_sub_pmd_start = end;
144 }
145 
146 /* Returns true if the PMD is completely unused and can be freed. */
vmemmap_unuse_sub_pmd(unsigned long start,unsigned long end)147 static bool vmemmap_unuse_sub_pmd(unsigned long start, unsigned long end)
148 {
149 	unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
150 
151 	vmemmap_flush_unused_sub_pmd();
152 	memset((void *)start, PAGE_UNUSED, end - start);
153 	return !memchr_inv((void *)page, PAGE_UNUSED, PMD_SIZE);
154 }
155 
156 /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
modify_pte_table(pmd_t * pmd,unsigned long addr,unsigned long end,bool add,bool direct)157 static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr,
158 				  unsigned long end, bool add, bool direct)
159 {
160 	unsigned long prot, pages = 0;
161 	int ret = -ENOMEM;
162 	pte_t *pte;
163 
164 	prot = pgprot_val(PAGE_KERNEL);
165 	if (!MACHINE_HAS_NX)
166 		prot &= ~_PAGE_NOEXEC;
167 
168 	pte = pte_offset_kernel(pmd, addr);
169 	for (; addr < end; addr += PAGE_SIZE, pte++) {
170 		if (!add) {
171 			if (pte_none(*pte))
172 				continue;
173 			if (!direct)
174 				vmem_free_pages((unsigned long) pfn_to_virt(pte_pfn(*pte)), 0);
175 			pte_clear(&init_mm, addr, pte);
176 		} else if (pte_none(*pte)) {
177 			if (!direct) {
178 				void *new_page = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
179 
180 				if (!new_page)
181 					goto out;
182 				set_pte(pte, __pte(__pa(new_page) | prot));
183 			} else {
184 				set_pte(pte, __pte(__pa(addr) | prot));
185 			}
186 		} else {
187 			continue;
188 		}
189 		pages++;
190 	}
191 	ret = 0;
192 out:
193 	if (direct)
194 		update_page_count(PG_DIRECT_MAP_4K, add ? pages : -pages);
195 	return ret;
196 }
197 
try_free_pte_table(pmd_t * pmd,unsigned long start)198 static void try_free_pte_table(pmd_t *pmd, unsigned long start)
199 {
200 	pte_t *pte;
201 	int i;
202 
203 	/* We can safely assume this is fully in 1:1 mapping & vmemmap area */
204 	pte = pte_offset_kernel(pmd, start);
205 	for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
206 		if (!pte_none(*pte))
207 			return;
208 	}
209 	vmem_pte_free((unsigned long *) pmd_deref(*pmd));
210 	pmd_clear(pmd);
211 }
212 
213 /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
modify_pmd_table(pud_t * pud,unsigned long addr,unsigned long end,bool add,bool direct)214 static int __ref modify_pmd_table(pud_t *pud, unsigned long addr,
215 				  unsigned long end, bool add, bool direct)
216 {
217 	unsigned long next, prot, pages = 0;
218 	int ret = -ENOMEM;
219 	pmd_t *pmd;
220 	pte_t *pte;
221 
222 	prot = pgprot_val(SEGMENT_KERNEL);
223 	if (!MACHINE_HAS_NX)
224 		prot &= ~_SEGMENT_ENTRY_NOEXEC;
225 
226 	pmd = pmd_offset(pud, addr);
227 	for (; addr < end; addr = next, pmd++) {
228 		next = pmd_addr_end(addr, end);
229 		if (!add) {
230 			if (pmd_none(*pmd))
231 				continue;
232 			if (pmd_large(*pmd)) {
233 				if (IS_ALIGNED(addr, PMD_SIZE) &&
234 				    IS_ALIGNED(next, PMD_SIZE)) {
235 					if (!direct)
236 						vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
237 					pmd_clear(pmd);
238 					pages++;
239 				} else if (!direct && vmemmap_unuse_sub_pmd(addr, next)) {
240 					vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
241 					pmd_clear(pmd);
242 				}
243 				continue;
244 			}
245 		} else if (pmd_none(*pmd)) {
246 			if (IS_ALIGNED(addr, PMD_SIZE) &&
247 			    IS_ALIGNED(next, PMD_SIZE) &&
248 			    MACHINE_HAS_EDAT1 && direct &&
249 			    !debug_pagealloc_enabled()) {
250 				set_pmd(pmd, __pmd(__pa(addr) | prot));
251 				pages++;
252 				continue;
253 			} else if (!direct && MACHINE_HAS_EDAT1) {
254 				void *new_page;
255 
256 				/*
257 				 * Use 1MB frames for vmemmap if available. We
258 				 * always use large frames even if they are only
259 				 * partially used. Otherwise we would have also
260 				 * page tables since vmemmap_populate gets
261 				 * called for each section separately.
262 				 */
263 				new_page = vmemmap_alloc_block(PMD_SIZE, NUMA_NO_NODE);
264 				if (new_page) {
265 					set_pmd(pmd, __pmd(__pa(new_page) | prot));
266 					if (!IS_ALIGNED(addr, PMD_SIZE) ||
267 					    !IS_ALIGNED(next, PMD_SIZE)) {
268 						vmemmap_use_new_sub_pmd(addr, next);
269 					}
270 					continue;
271 				}
272 			}
273 			pte = vmem_pte_alloc();
274 			if (!pte)
275 				goto out;
276 			pmd_populate(&init_mm, pmd, pte);
277 		} else if (pmd_large(*pmd)) {
278 			if (!direct)
279 				vmemmap_use_sub_pmd(addr, next);
280 			continue;
281 		}
282 		ret = modify_pte_table(pmd, addr, next, add, direct);
283 		if (ret)
284 			goto out;
285 		if (!add)
286 			try_free_pte_table(pmd, addr & PMD_MASK);
287 	}
288 	ret = 0;
289 out:
290 	if (direct)
291 		update_page_count(PG_DIRECT_MAP_1M, add ? pages : -pages);
292 	return ret;
293 }
294 
try_free_pmd_table(pud_t * pud,unsigned long start)295 static void try_free_pmd_table(pud_t *pud, unsigned long start)
296 {
297 	pmd_t *pmd;
298 	int i;
299 
300 	pmd = pmd_offset(pud, start);
301 	for (i = 0; i < PTRS_PER_PMD; i++, pmd++)
302 		if (!pmd_none(*pmd))
303 			return;
304 	vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER);
305 	pud_clear(pud);
306 }
307 
modify_pud_table(p4d_t * p4d,unsigned long addr,unsigned long end,bool add,bool direct)308 static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end,
309 			    bool add, bool direct)
310 {
311 	unsigned long next, prot, pages = 0;
312 	int ret = -ENOMEM;
313 	pud_t *pud;
314 	pmd_t *pmd;
315 
316 	prot = pgprot_val(REGION3_KERNEL);
317 	if (!MACHINE_HAS_NX)
318 		prot &= ~_REGION_ENTRY_NOEXEC;
319 	pud = pud_offset(p4d, addr);
320 	for (; addr < end; addr = next, pud++) {
321 		next = pud_addr_end(addr, end);
322 		if (!add) {
323 			if (pud_none(*pud))
324 				continue;
325 			if (pud_large(*pud)) {
326 				if (IS_ALIGNED(addr, PUD_SIZE) &&
327 				    IS_ALIGNED(next, PUD_SIZE)) {
328 					pud_clear(pud);
329 					pages++;
330 				}
331 				continue;
332 			}
333 		} else if (pud_none(*pud)) {
334 			if (IS_ALIGNED(addr, PUD_SIZE) &&
335 			    IS_ALIGNED(next, PUD_SIZE) &&
336 			    MACHINE_HAS_EDAT2 && direct &&
337 			    !debug_pagealloc_enabled()) {
338 				set_pud(pud, __pud(__pa(addr) | prot));
339 				pages++;
340 				continue;
341 			}
342 			pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
343 			if (!pmd)
344 				goto out;
345 			pud_populate(&init_mm, pud, pmd);
346 		} else if (pud_large(*pud)) {
347 			continue;
348 		}
349 		ret = modify_pmd_table(pud, addr, next, add, direct);
350 		if (ret)
351 			goto out;
352 		if (!add)
353 			try_free_pmd_table(pud, addr & PUD_MASK);
354 	}
355 	ret = 0;
356 out:
357 	if (direct)
358 		update_page_count(PG_DIRECT_MAP_2G, add ? pages : -pages);
359 	return ret;
360 }
361 
try_free_pud_table(p4d_t * p4d,unsigned long start)362 static void try_free_pud_table(p4d_t *p4d, unsigned long start)
363 {
364 	pud_t *pud;
365 	int i;
366 
367 	pud = pud_offset(p4d, start);
368 	for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
369 		if (!pud_none(*pud))
370 			return;
371 	}
372 	vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER);
373 	p4d_clear(p4d);
374 }
375 
modify_p4d_table(pgd_t * pgd,unsigned long addr,unsigned long end,bool add,bool direct)376 static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end,
377 			    bool add, bool direct)
378 {
379 	unsigned long next;
380 	int ret = -ENOMEM;
381 	p4d_t *p4d;
382 	pud_t *pud;
383 
384 	p4d = p4d_offset(pgd, addr);
385 	for (; addr < end; addr = next, p4d++) {
386 		next = p4d_addr_end(addr, end);
387 		if (!add) {
388 			if (p4d_none(*p4d))
389 				continue;
390 		} else if (p4d_none(*p4d)) {
391 			pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
392 			if (!pud)
393 				goto out;
394 			p4d_populate(&init_mm, p4d, pud);
395 		}
396 		ret = modify_pud_table(p4d, addr, next, add, direct);
397 		if (ret)
398 			goto out;
399 		if (!add)
400 			try_free_pud_table(p4d, addr & P4D_MASK);
401 	}
402 	ret = 0;
403 out:
404 	return ret;
405 }
406 
try_free_p4d_table(pgd_t * pgd,unsigned long start)407 static void try_free_p4d_table(pgd_t *pgd, unsigned long start)
408 {
409 	p4d_t *p4d;
410 	int i;
411 
412 	p4d = p4d_offset(pgd, start);
413 	for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
414 		if (!p4d_none(*p4d))
415 			return;
416 	}
417 	vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER);
418 	pgd_clear(pgd);
419 }
420 
modify_pagetable(unsigned long start,unsigned long end,bool add,bool direct)421 static int modify_pagetable(unsigned long start, unsigned long end, bool add,
422 			    bool direct)
423 {
424 	unsigned long addr, next;
425 	int ret = -ENOMEM;
426 	pgd_t *pgd;
427 	p4d_t *p4d;
428 
429 	if (WARN_ON_ONCE(!PAGE_ALIGNED(start | end)))
430 		return -EINVAL;
431 	/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
432 	if (WARN_ON_ONCE(end > VMALLOC_START))
433 		return -EINVAL;
434 	for (addr = start; addr < end; addr = next) {
435 		next = pgd_addr_end(addr, end);
436 		pgd = pgd_offset_k(addr);
437 
438 		if (!add) {
439 			if (pgd_none(*pgd))
440 				continue;
441 		} else if (pgd_none(*pgd)) {
442 			p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
443 			if (!p4d)
444 				goto out;
445 			pgd_populate(&init_mm, pgd, p4d);
446 		}
447 		ret = modify_p4d_table(pgd, addr, next, add, direct);
448 		if (ret)
449 			goto out;
450 		if (!add)
451 			try_free_p4d_table(pgd, addr & PGDIR_MASK);
452 	}
453 	ret = 0;
454 out:
455 	if (!add)
456 		flush_tlb_kernel_range(start, end);
457 	return ret;
458 }
459 
add_pagetable(unsigned long start,unsigned long end,bool direct)460 static int add_pagetable(unsigned long start, unsigned long end, bool direct)
461 {
462 	return modify_pagetable(start, end, true, direct);
463 }
464 
remove_pagetable(unsigned long start,unsigned long end,bool direct)465 static int remove_pagetable(unsigned long start, unsigned long end, bool direct)
466 {
467 	return modify_pagetable(start, end, false, direct);
468 }
469 
470 /*
471  * Add a physical memory range to the 1:1 mapping.
472  */
vmem_add_range(unsigned long start,unsigned long size)473 static int vmem_add_range(unsigned long start, unsigned long size)
474 {
475 	start = (unsigned long)__va(start);
476 	return add_pagetable(start, start + size, true);
477 }
478 
479 /*
480  * Remove a physical memory range from the 1:1 mapping.
481  */
vmem_remove_range(unsigned long start,unsigned long size)482 static void vmem_remove_range(unsigned long start, unsigned long size)
483 {
484 	start = (unsigned long)__va(start);
485 	remove_pagetable(start, start + size, true);
486 }
487 
488 /*
489  * Add a backed mem_map array to the virtual mem_map array.
490  */
vmemmap_populate(unsigned long start,unsigned long end,int node,struct vmem_altmap * altmap)491 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
492 			       struct vmem_altmap *altmap)
493 {
494 	int ret;
495 
496 	mutex_lock(&vmem_mutex);
497 	/* We don't care about the node, just use NUMA_NO_NODE on allocations */
498 	ret = add_pagetable(start, end, false);
499 	if (ret)
500 		remove_pagetable(start, end, false);
501 	mutex_unlock(&vmem_mutex);
502 	return ret;
503 }
504 
vmemmap_free(unsigned long start,unsigned long end,struct vmem_altmap * altmap)505 void vmemmap_free(unsigned long start, unsigned long end,
506 		  struct vmem_altmap *altmap)
507 {
508 	mutex_lock(&vmem_mutex);
509 	remove_pagetable(start, end, false);
510 	mutex_unlock(&vmem_mutex);
511 }
512 
vmem_remove_mapping(unsigned long start,unsigned long size)513 void vmem_remove_mapping(unsigned long start, unsigned long size)
514 {
515 	mutex_lock(&vmem_mutex);
516 	vmem_remove_range(start, size);
517 	mutex_unlock(&vmem_mutex);
518 }
519 
arch_get_mappable_range(void)520 struct range arch_get_mappable_range(void)
521 {
522 	struct range mhp_range;
523 
524 	mhp_range.start = 0;
525 	mhp_range.end = max_mappable - 1;
526 	return mhp_range;
527 }
528 
vmem_add_mapping(unsigned long start,unsigned long size)529 int vmem_add_mapping(unsigned long start, unsigned long size)
530 {
531 	struct range range = arch_get_mappable_range();
532 	int ret;
533 
534 	if (start < range.start ||
535 	    start + size > range.end + 1 ||
536 	    start + size < start)
537 		return -ERANGE;
538 
539 	mutex_lock(&vmem_mutex);
540 	ret = vmem_add_range(start, size);
541 	if (ret)
542 		vmem_remove_range(start, size);
543 	mutex_unlock(&vmem_mutex);
544 	return ret;
545 }
546 
547 /*
548  * Allocate new or return existing page-table entry, but do not map it
549  * to any physical address. If missing, allocate segment- and region-
550  * table entries along. Meeting a large segment- or region-table entry
551  * while traversing is an error, since the function is expected to be
552  * called against virtual regions reserved for 4KB mappings only.
553  */
vmem_get_alloc_pte(unsigned long addr,bool alloc)554 pte_t *vmem_get_alloc_pte(unsigned long addr, bool alloc)
555 {
556 	pte_t *ptep = NULL;
557 	pgd_t *pgd;
558 	p4d_t *p4d;
559 	pud_t *pud;
560 	pmd_t *pmd;
561 	pte_t *pte;
562 
563 	pgd = pgd_offset_k(addr);
564 	if (pgd_none(*pgd)) {
565 		if (!alloc)
566 			goto out;
567 		p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
568 		if (!p4d)
569 			goto out;
570 		pgd_populate(&init_mm, pgd, p4d);
571 	}
572 	p4d = p4d_offset(pgd, addr);
573 	if (p4d_none(*p4d)) {
574 		if (!alloc)
575 			goto out;
576 		pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
577 		if (!pud)
578 			goto out;
579 		p4d_populate(&init_mm, p4d, pud);
580 	}
581 	pud = pud_offset(p4d, addr);
582 	if (pud_none(*pud)) {
583 		if (!alloc)
584 			goto out;
585 		pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
586 		if (!pmd)
587 			goto out;
588 		pud_populate(&init_mm, pud, pmd);
589 	} else if (WARN_ON_ONCE(pud_large(*pud))) {
590 		goto out;
591 	}
592 	pmd = pmd_offset(pud, addr);
593 	if (pmd_none(*pmd)) {
594 		if (!alloc)
595 			goto out;
596 		pte = vmem_pte_alloc();
597 		if (!pte)
598 			goto out;
599 		pmd_populate(&init_mm, pmd, pte);
600 	} else if (WARN_ON_ONCE(pmd_large(*pmd))) {
601 		goto out;
602 	}
603 	ptep = pte_offset_kernel(pmd, addr);
604 out:
605 	return ptep;
606 }
607 
__vmem_map_4k_page(unsigned long addr,unsigned long phys,pgprot_t prot,bool alloc)608 int __vmem_map_4k_page(unsigned long addr, unsigned long phys, pgprot_t prot, bool alloc)
609 {
610 	pte_t *ptep, pte;
611 
612 	if (!IS_ALIGNED(addr, PAGE_SIZE))
613 		return -EINVAL;
614 	ptep = vmem_get_alloc_pte(addr, alloc);
615 	if (!ptep)
616 		return -ENOMEM;
617 	__ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
618 	pte = mk_pte_phys(phys, prot);
619 	set_pte(ptep, pte);
620 	return 0;
621 }
622 
vmem_map_4k_page(unsigned long addr,unsigned long phys,pgprot_t prot)623 int vmem_map_4k_page(unsigned long addr, unsigned long phys, pgprot_t prot)
624 {
625 	int rc;
626 
627 	mutex_lock(&vmem_mutex);
628 	rc = __vmem_map_4k_page(addr, phys, prot, true);
629 	mutex_unlock(&vmem_mutex);
630 	return rc;
631 }
632 
vmem_unmap_4k_page(unsigned long addr)633 void vmem_unmap_4k_page(unsigned long addr)
634 {
635 	pte_t *ptep;
636 
637 	mutex_lock(&vmem_mutex);
638 	ptep = virt_to_kpte(addr);
639 	__ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
640 	pte_clear(&init_mm, addr, ptep);
641 	mutex_unlock(&vmem_mutex);
642 }
643 
vmem_map_init(void)644 void __init vmem_map_init(void)
645 {
646 	__set_memory_rox(_stext, _etext);
647 	__set_memory_ro(_etext, __end_rodata);
648 	__set_memory_rox(_sinittext, _einittext);
649 	__set_memory_rox(__stext_amode31, __etext_amode31);
650 	/*
651 	 * If the BEAR-enhancement facility is not installed the first
652 	 * prefix page is used to return to the previous context with
653 	 * an LPSWE instruction and therefore must be executable.
654 	 */
655 	if (!static_key_enabled(&cpu_has_bear))
656 		set_memory_x(0, 1);
657 	if (debug_pagealloc_enabled()) {
658 		/*
659 		 * Use RELOC_HIDE() as long as __va(0) translates to NULL,
660 		 * since performing pointer arithmetic on a NULL pointer
661 		 * has undefined behavior and generates compiler warnings.
662 		 */
663 		__set_memory_4k(__va(0), RELOC_HIDE(__va(0), ident_map_size));
664 	}
665 	if (MACHINE_HAS_NX)
666 		ctl_set_bit(0, 20);
667 	pr_info("Write protected kernel read-only data: %luk\n",
668 		(unsigned long)(__end_rodata - _stext) >> 10);
669 }
670