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