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 <asm/cacheflush.h>
15 #include <asm/nospec-branch.h>
16 #include <asm/pgalloc.h>
17 #include <asm/setup.h>
18 #include <asm/tlbflush.h>
19 #include <asm/sections.h>
20 #include <asm/set_memory.h>
21 
22 static DEFINE_MUTEX(vmem_mutex);
23 
vmem_alloc_pages(unsigned int order)24 static void __ref *vmem_alloc_pages(unsigned int order)
25 {
26 	unsigned long size = PAGE_SIZE << order;
27 
28 	if (slab_is_available())
29 		return (void *)__get_free_pages(GFP_KERNEL, order);
30 	return memblock_alloc(size, size);
31 }
32 
vmem_free_pages(unsigned long addr,int order)33 static void vmem_free_pages(unsigned long addr, int order)
34 {
35 	/* We don't expect boot memory to be removed ever. */
36 	if (!slab_is_available() ||
37 	    WARN_ON_ONCE(PageReserved(virt_to_page(addr))))
38 		return;
39 	free_pages(addr, order);
40 }
41 
vmem_crst_alloc(unsigned long val)42 void *vmem_crst_alloc(unsigned long val)
43 {
44 	unsigned long *table;
45 
46 	table = vmem_alloc_pages(CRST_ALLOC_ORDER);
47 	if (table)
48 		crst_table_init(table, val);
49 	return table;
50 }
51 
vmem_pte_alloc(void)52 pte_t __ref *vmem_pte_alloc(void)
53 {
54 	unsigned long size = PTRS_PER_PTE * sizeof(pte_t);
55 	pte_t *pte;
56 
57 	if (slab_is_available())
58 		pte = (pte_t *) page_table_alloc(&init_mm);
59 	else
60 		pte = (pte_t *) memblock_alloc(size, size);
61 	if (!pte)
62 		return NULL;
63 	memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
64 	return pte;
65 }
66 
vmem_pte_free(unsigned long * table)67 static void vmem_pte_free(unsigned long *table)
68 {
69 	/* We don't expect boot memory to be removed ever. */
70 	if (!slab_is_available() ||
71 	    WARN_ON_ONCE(PageReserved(virt_to_page(table))))
72 		return;
73 	page_table_free(&init_mm, table);
74 }
75 
76 #define PAGE_UNUSED 0xFD
77 
78 /*
79  * The unused vmemmap range, which was not yet memset(PAGE_UNUSED) ranges
80  * from unused_sub_pmd_start to next PMD_SIZE boundary.
81  */
82 static unsigned long unused_sub_pmd_start;
83 
vmemmap_flush_unused_sub_pmd(void)84 static void vmemmap_flush_unused_sub_pmd(void)
85 {
86 	if (!unused_sub_pmd_start)
87 		return;
88 	memset((void *)unused_sub_pmd_start, PAGE_UNUSED,
89 	       ALIGN(unused_sub_pmd_start, PMD_SIZE) - unused_sub_pmd_start);
90 	unused_sub_pmd_start = 0;
91 }
92 
vmemmap_mark_sub_pmd_used(unsigned long start,unsigned long end)93 static void vmemmap_mark_sub_pmd_used(unsigned long start, unsigned long end)
94 {
95 	/*
96 	 * As we expect to add in the same granularity as we remove, it's
97 	 * sufficient to mark only some piece used to block the memmap page from
98 	 * getting removed (just in case the memmap never gets initialized,
99 	 * e.g., because the memory block never gets onlined).
100 	 */
101 	memset((void *)start, 0, sizeof(struct page));
102 }
103 
vmemmap_use_sub_pmd(unsigned long start,unsigned long end)104 static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end)
105 {
106 	/*
107 	 * We only optimize if the new used range directly follows the
108 	 * previously unused range (esp., when populating consecutive sections).
109 	 */
110 	if (unused_sub_pmd_start == start) {
111 		unused_sub_pmd_start = end;
112 		if (likely(IS_ALIGNED(unused_sub_pmd_start, PMD_SIZE)))
113 			unused_sub_pmd_start = 0;
114 		return;
115 	}
116 	vmemmap_flush_unused_sub_pmd();
117 	vmemmap_mark_sub_pmd_used(start, end);
118 }
119 
vmemmap_use_new_sub_pmd(unsigned long start,unsigned long end)120 static void vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end)
121 {
122 	unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
123 
124 	vmemmap_flush_unused_sub_pmd();
125 
126 	/* Could be our memmap page is filled with PAGE_UNUSED already ... */
127 	vmemmap_mark_sub_pmd_used(start, end);
128 
129 	/* Mark the unused parts of the new memmap page PAGE_UNUSED. */
130 	if (!IS_ALIGNED(start, PMD_SIZE))
131 		memset((void *)page, PAGE_UNUSED, start - page);
132 	/*
133 	 * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of
134 	 * consecutive sections. Remember for the last added PMD the last
135 	 * unused range in the populated PMD.
136 	 */
137 	if (!IS_ALIGNED(end, PMD_SIZE))
138 		unused_sub_pmd_start = end;
139 }
140 
141 /* Returns true if the PMD is completely unused and can be freed. */
vmemmap_unuse_sub_pmd(unsigned long start,unsigned long end)142 static bool vmemmap_unuse_sub_pmd(unsigned long start, unsigned long end)
143 {
144 	unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
145 
146 	vmemmap_flush_unused_sub_pmd();
147 	memset((void *)start, PAGE_UNUSED, end - start);
148 	return !memchr_inv((void *)page, PAGE_UNUSED, PMD_SIZE);
149 }
150 
151 /* __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)152 static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr,
153 				  unsigned long end, bool add, bool direct)
154 {
155 	unsigned long prot, pages = 0;
156 	int ret = -ENOMEM;
157 	pte_t *pte;
158 
159 	prot = pgprot_val(PAGE_KERNEL);
160 	if (!MACHINE_HAS_NX)
161 		prot &= ~_PAGE_NOEXEC;
162 
163 	pte = pte_offset_kernel(pmd, addr);
164 	for (; addr < end; addr += PAGE_SIZE, pte++) {
165 		if (!add) {
166 			if (pte_none(*pte))
167 				continue;
168 			if (!direct)
169 				vmem_free_pages((unsigned long) pfn_to_virt(pte_pfn(*pte)), 0);
170 			pte_clear(&init_mm, addr, pte);
171 		} else if (pte_none(*pte)) {
172 			if (!direct) {
173 				void *new_page = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
174 
175 				if (!new_page)
176 					goto out;
177 				set_pte(pte, __pte(__pa(new_page) | prot));
178 			} else {
179 				set_pte(pte, __pte(__pa(addr) | prot));
180 			}
181 		} else {
182 			continue;
183 		}
184 		pages++;
185 	}
186 	ret = 0;
187 out:
188 	if (direct)
189 		update_page_count(PG_DIRECT_MAP_4K, add ? pages : -pages);
190 	return ret;
191 }
192 
try_free_pte_table(pmd_t * pmd,unsigned long start)193 static void try_free_pte_table(pmd_t *pmd, unsigned long start)
194 {
195 	pte_t *pte;
196 	int i;
197 
198 	/* We can safely assume this is fully in 1:1 mapping & vmemmap area */
199 	pte = pte_offset_kernel(pmd, start);
200 	for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
201 		if (!pte_none(*pte))
202 			return;
203 	}
204 	vmem_pte_free((unsigned long *) pmd_deref(*pmd));
205 	pmd_clear(pmd);
206 }
207 
208 /* __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)209 static int __ref modify_pmd_table(pud_t *pud, unsigned long addr,
210 				  unsigned long end, bool add, bool direct)
211 {
212 	unsigned long next, prot, pages = 0;
213 	int ret = -ENOMEM;
214 	pmd_t *pmd;
215 	pte_t *pte;
216 
217 	prot = pgprot_val(SEGMENT_KERNEL);
218 	if (!MACHINE_HAS_NX)
219 		prot &= ~_SEGMENT_ENTRY_NOEXEC;
220 
221 	pmd = pmd_offset(pud, addr);
222 	for (; addr < end; addr = next, pmd++) {
223 		next = pmd_addr_end(addr, end);
224 		if (!add) {
225 			if (pmd_none(*pmd))
226 				continue;
227 			if (pmd_large(*pmd)) {
228 				if (IS_ALIGNED(addr, PMD_SIZE) &&
229 				    IS_ALIGNED(next, PMD_SIZE)) {
230 					if (!direct)
231 						vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
232 					pmd_clear(pmd);
233 					pages++;
234 				} else if (!direct && vmemmap_unuse_sub_pmd(addr, next)) {
235 					vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
236 					pmd_clear(pmd);
237 				}
238 				continue;
239 			}
240 		} else if (pmd_none(*pmd)) {
241 			if (IS_ALIGNED(addr, PMD_SIZE) &&
242 			    IS_ALIGNED(next, PMD_SIZE) &&
243 			    MACHINE_HAS_EDAT1 && direct &&
244 			    !debug_pagealloc_enabled()) {
245 				set_pmd(pmd, __pmd(__pa(addr) | prot));
246 				pages++;
247 				continue;
248 			} else if (!direct && MACHINE_HAS_EDAT1) {
249 				void *new_page;
250 
251 				/*
252 				 * Use 1MB frames for vmemmap if available. We
253 				 * always use large frames even if they are only
254 				 * partially used. Otherwise we would have also
255 				 * page tables since vmemmap_populate gets
256 				 * called for each section separately.
257 				 */
258 				new_page = vmemmap_alloc_block(PMD_SIZE, NUMA_NO_NODE);
259 				if (new_page) {
260 					set_pmd(pmd, __pmd(__pa(new_page) | prot));
261 					if (!IS_ALIGNED(addr, PMD_SIZE) ||
262 					    !IS_ALIGNED(next, PMD_SIZE)) {
263 						vmemmap_use_new_sub_pmd(addr, next);
264 					}
265 					continue;
266 				}
267 			}
268 			pte = vmem_pte_alloc();
269 			if (!pte)
270 				goto out;
271 			pmd_populate(&init_mm, pmd, pte);
272 		} else if (pmd_large(*pmd)) {
273 			if (!direct)
274 				vmemmap_use_sub_pmd(addr, next);
275 			continue;
276 		}
277 		ret = modify_pte_table(pmd, addr, next, add, direct);
278 		if (ret)
279 			goto out;
280 		if (!add)
281 			try_free_pte_table(pmd, addr & PMD_MASK);
282 	}
283 	ret = 0;
284 out:
285 	if (direct)
286 		update_page_count(PG_DIRECT_MAP_1M, add ? pages : -pages);
287 	return ret;
288 }
289 
try_free_pmd_table(pud_t * pud,unsigned long start)290 static void try_free_pmd_table(pud_t *pud, unsigned long start)
291 {
292 	const unsigned long end = start + PUD_SIZE;
293 	pmd_t *pmd;
294 	int i;
295 
296 	/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
297 	if (end > VMALLOC_START)
298 		return;
299 #ifdef CONFIG_KASAN
300 	if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
301 		return;
302 #endif
303 	pmd = pmd_offset(pud, start);
304 	for (i = 0; i < PTRS_PER_PMD; i++, pmd++)
305 		if (!pmd_none(*pmd))
306 			return;
307 	vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER);
308 	pud_clear(pud);
309 }
310 
modify_pud_table(p4d_t * p4d,unsigned long addr,unsigned long end,bool add,bool direct)311 static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end,
312 			    bool add, bool direct)
313 {
314 	unsigned long next, prot, pages = 0;
315 	int ret = -ENOMEM;
316 	pud_t *pud;
317 	pmd_t *pmd;
318 
319 	prot = pgprot_val(REGION3_KERNEL);
320 	if (!MACHINE_HAS_NX)
321 		prot &= ~_REGION_ENTRY_NOEXEC;
322 	pud = pud_offset(p4d, addr);
323 	for (; addr < end; addr = next, pud++) {
324 		next = pud_addr_end(addr, end);
325 		if (!add) {
326 			if (pud_none(*pud))
327 				continue;
328 			if (pud_large(*pud)) {
329 				if (IS_ALIGNED(addr, PUD_SIZE) &&
330 				    IS_ALIGNED(next, PUD_SIZE)) {
331 					pud_clear(pud);
332 					pages++;
333 				}
334 				continue;
335 			}
336 		} else if (pud_none(*pud)) {
337 			if (IS_ALIGNED(addr, PUD_SIZE) &&
338 			    IS_ALIGNED(next, PUD_SIZE) &&
339 			    MACHINE_HAS_EDAT2 && direct &&
340 			    !debug_pagealloc_enabled()) {
341 				set_pud(pud, __pud(__pa(addr) | prot));
342 				pages++;
343 				continue;
344 			}
345 			pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
346 			if (!pmd)
347 				goto out;
348 			pud_populate(&init_mm, pud, pmd);
349 		} else if (pud_large(*pud)) {
350 			continue;
351 		}
352 		ret = modify_pmd_table(pud, addr, next, add, direct);
353 		if (ret)
354 			goto out;
355 		if (!add)
356 			try_free_pmd_table(pud, addr & PUD_MASK);
357 	}
358 	ret = 0;
359 out:
360 	if (direct)
361 		update_page_count(PG_DIRECT_MAP_2G, add ? pages : -pages);
362 	return ret;
363 }
364 
try_free_pud_table(p4d_t * p4d,unsigned long start)365 static void try_free_pud_table(p4d_t *p4d, unsigned long start)
366 {
367 	const unsigned long end = start + P4D_SIZE;
368 	pud_t *pud;
369 	int i;
370 
371 	/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
372 	if (end > VMALLOC_START)
373 		return;
374 #ifdef CONFIG_KASAN
375 	if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
376 		return;
377 #endif
378 
379 	pud = pud_offset(p4d, start);
380 	for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
381 		if (!pud_none(*pud))
382 			return;
383 	}
384 	vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER);
385 	p4d_clear(p4d);
386 }
387 
modify_p4d_table(pgd_t * pgd,unsigned long addr,unsigned long end,bool add,bool direct)388 static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end,
389 			    bool add, bool direct)
390 {
391 	unsigned long next;
392 	int ret = -ENOMEM;
393 	p4d_t *p4d;
394 	pud_t *pud;
395 
396 	p4d = p4d_offset(pgd, addr);
397 	for (; addr < end; addr = next, p4d++) {
398 		next = p4d_addr_end(addr, end);
399 		if (!add) {
400 			if (p4d_none(*p4d))
401 				continue;
402 		} else if (p4d_none(*p4d)) {
403 			pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
404 			if (!pud)
405 				goto out;
406 			p4d_populate(&init_mm, p4d, pud);
407 		}
408 		ret = modify_pud_table(p4d, addr, next, add, direct);
409 		if (ret)
410 			goto out;
411 		if (!add)
412 			try_free_pud_table(p4d, addr & P4D_MASK);
413 	}
414 	ret = 0;
415 out:
416 	return ret;
417 }
418 
try_free_p4d_table(pgd_t * pgd,unsigned long start)419 static void try_free_p4d_table(pgd_t *pgd, unsigned long start)
420 {
421 	const unsigned long end = start + PGDIR_SIZE;
422 	p4d_t *p4d;
423 	int i;
424 
425 	/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
426 	if (end > VMALLOC_START)
427 		return;
428 #ifdef CONFIG_KASAN
429 	if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
430 		return;
431 #endif
432 
433 	p4d = p4d_offset(pgd, start);
434 	for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
435 		if (!p4d_none(*p4d))
436 			return;
437 	}
438 	vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER);
439 	pgd_clear(pgd);
440 }
441 
modify_pagetable(unsigned long start,unsigned long end,bool add,bool direct)442 static int modify_pagetable(unsigned long start, unsigned long end, bool add,
443 			    bool direct)
444 {
445 	unsigned long addr, next;
446 	int ret = -ENOMEM;
447 	pgd_t *pgd;
448 	p4d_t *p4d;
449 
450 	if (WARN_ON_ONCE(!PAGE_ALIGNED(start | end)))
451 		return -EINVAL;
452 	for (addr = start; addr < end; addr = next) {
453 		next = pgd_addr_end(addr, end);
454 		pgd = pgd_offset_k(addr);
455 
456 		if (!add) {
457 			if (pgd_none(*pgd))
458 				continue;
459 		} else if (pgd_none(*pgd)) {
460 			p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
461 			if (!p4d)
462 				goto out;
463 			pgd_populate(&init_mm, pgd, p4d);
464 		}
465 		ret = modify_p4d_table(pgd, addr, next, add, direct);
466 		if (ret)
467 			goto out;
468 		if (!add)
469 			try_free_p4d_table(pgd, addr & PGDIR_MASK);
470 	}
471 	ret = 0;
472 out:
473 	if (!add)
474 		flush_tlb_kernel_range(start, end);
475 	return ret;
476 }
477 
add_pagetable(unsigned long start,unsigned long end,bool direct)478 static int add_pagetable(unsigned long start, unsigned long end, bool direct)
479 {
480 	return modify_pagetable(start, end, true, direct);
481 }
482 
remove_pagetable(unsigned long start,unsigned long end,bool direct)483 static int remove_pagetable(unsigned long start, unsigned long end, bool direct)
484 {
485 	return modify_pagetable(start, end, false, direct);
486 }
487 
488 /*
489  * Add a physical memory range to the 1:1 mapping.
490  */
vmem_add_range(unsigned long start,unsigned long size)491 static int vmem_add_range(unsigned long start, unsigned long size)
492 {
493 	return add_pagetable(start, start + size, true);
494 }
495 
496 /*
497  * Remove a physical memory range from the 1:1 mapping.
498  */
vmem_remove_range(unsigned long start,unsigned long size)499 static void vmem_remove_range(unsigned long start, unsigned long size)
500 {
501 	remove_pagetable(start, start + size, true);
502 }
503 
504 /*
505  * Add a backed mem_map array to the virtual mem_map array.
506  */
vmemmap_populate(unsigned long start,unsigned long end,int node,struct vmem_altmap * altmap)507 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
508 			       struct vmem_altmap *altmap)
509 {
510 	int ret;
511 
512 	mutex_lock(&vmem_mutex);
513 	/* We don't care about the node, just use NUMA_NO_NODE on allocations */
514 	ret = add_pagetable(start, end, false);
515 	if (ret)
516 		remove_pagetable(start, end, false);
517 	mutex_unlock(&vmem_mutex);
518 	return ret;
519 }
520 
vmemmap_free(unsigned long start,unsigned long end,struct vmem_altmap * altmap)521 void vmemmap_free(unsigned long start, unsigned long end,
522 		  struct vmem_altmap *altmap)
523 {
524 	mutex_lock(&vmem_mutex);
525 	remove_pagetable(start, end, false);
526 	mutex_unlock(&vmem_mutex);
527 }
528 
vmem_remove_mapping(unsigned long start,unsigned long size)529 void vmem_remove_mapping(unsigned long start, unsigned long size)
530 {
531 	mutex_lock(&vmem_mutex);
532 	vmem_remove_range(start, size);
533 	mutex_unlock(&vmem_mutex);
534 }
535 
arch_get_mappable_range(void)536 struct range arch_get_mappable_range(void)
537 {
538 	struct range mhp_range;
539 
540 	mhp_range.start = 0;
541 	mhp_range.end =  VMEM_MAX_PHYS - 1;
542 	return mhp_range;
543 }
544 
vmem_add_mapping(unsigned long start,unsigned long size)545 int vmem_add_mapping(unsigned long start, unsigned long size)
546 {
547 	struct range range = arch_get_mappable_range();
548 	int ret;
549 
550 	if (start < range.start ||
551 	    start + size > range.end + 1 ||
552 	    start + size < start)
553 		return -ERANGE;
554 
555 	mutex_lock(&vmem_mutex);
556 	ret = vmem_add_range(start, size);
557 	if (ret)
558 		vmem_remove_range(start, size);
559 	mutex_unlock(&vmem_mutex);
560 	return ret;
561 }
562 
563 /*
564  * Allocate new or return existing page-table entry, but do not map it
565  * to any physical address. If missing, allocate segment- and region-
566  * table entries along. Meeting a large segment- or region-table entry
567  * while traversing is an error, since the function is expected to be
568  * called against virtual regions reserverd for 4KB mappings only.
569  */
vmem_get_alloc_pte(unsigned long addr,bool alloc)570 pte_t *vmem_get_alloc_pte(unsigned long addr, bool alloc)
571 {
572 	pte_t *ptep = NULL;
573 	pgd_t *pgd;
574 	p4d_t *p4d;
575 	pud_t *pud;
576 	pmd_t *pmd;
577 	pte_t *pte;
578 
579 	pgd = pgd_offset_k(addr);
580 	if (pgd_none(*pgd)) {
581 		if (!alloc)
582 			goto out;
583 		p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
584 		if (!p4d)
585 			goto out;
586 		pgd_populate(&init_mm, pgd, p4d);
587 	}
588 	p4d = p4d_offset(pgd, addr);
589 	if (p4d_none(*p4d)) {
590 		if (!alloc)
591 			goto out;
592 		pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
593 		if (!pud)
594 			goto out;
595 		p4d_populate(&init_mm, p4d, pud);
596 	}
597 	pud = pud_offset(p4d, addr);
598 	if (pud_none(*pud)) {
599 		if (!alloc)
600 			goto out;
601 		pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
602 		if (!pmd)
603 			goto out;
604 		pud_populate(&init_mm, pud, pmd);
605 	} else if (WARN_ON_ONCE(pud_large(*pud))) {
606 		goto out;
607 	}
608 	pmd = pmd_offset(pud, addr);
609 	if (pmd_none(*pmd)) {
610 		if (!alloc)
611 			goto out;
612 		pte = vmem_pte_alloc();
613 		if (!pte)
614 			goto out;
615 		pmd_populate(&init_mm, pmd, pte);
616 	} else if (WARN_ON_ONCE(pmd_large(*pmd))) {
617 		goto out;
618 	}
619 	ptep = pte_offset_kernel(pmd, addr);
620 out:
621 	return ptep;
622 }
623 
__vmem_map_4k_page(unsigned long addr,unsigned long phys,pgprot_t prot,bool alloc)624 int __vmem_map_4k_page(unsigned long addr, unsigned long phys, pgprot_t prot, bool alloc)
625 {
626 	pte_t *ptep, pte;
627 
628 	if (!IS_ALIGNED(addr, PAGE_SIZE))
629 		return -EINVAL;
630 	ptep = vmem_get_alloc_pte(addr, alloc);
631 	if (!ptep)
632 		return -ENOMEM;
633 	__ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
634 	pte = mk_pte_phys(phys, prot);
635 	set_pte(ptep, pte);
636 	return 0;
637 }
638 
vmem_map_4k_page(unsigned long addr,unsigned long phys,pgprot_t prot)639 int vmem_map_4k_page(unsigned long addr, unsigned long phys, pgprot_t prot)
640 {
641 	int rc;
642 
643 	mutex_lock(&vmem_mutex);
644 	rc = __vmem_map_4k_page(addr, phys, prot, true);
645 	mutex_unlock(&vmem_mutex);
646 	return rc;
647 }
648 
vmem_unmap_4k_page(unsigned long addr)649 void vmem_unmap_4k_page(unsigned long addr)
650 {
651 	pte_t *ptep;
652 
653 	mutex_lock(&vmem_mutex);
654 	ptep = virt_to_kpte(addr);
655 	__ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
656 	pte_clear(&init_mm, addr, ptep);
657 	mutex_unlock(&vmem_mutex);
658 }
659 
660 /*
661  * map whole physical memory to virtual memory (identity mapping)
662  * we reserve enough space in the vmalloc area for vmemmap to hotplug
663  * additional memory segments.
664  */
vmem_map_init(void)665 void __init vmem_map_init(void)
666 {
667 	phys_addr_t base, end;
668 	u64 i;
669 
670 	for_each_mem_range(i, &base, &end)
671 		vmem_add_range(base, end - base);
672 	__set_memory((unsigned long)_stext,
673 		     (unsigned long)(_etext - _stext) >> PAGE_SHIFT,
674 		     SET_MEMORY_RO | SET_MEMORY_X);
675 	__set_memory((unsigned long)_etext,
676 		     (unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT,
677 		     SET_MEMORY_RO);
678 	__set_memory((unsigned long)_sinittext,
679 		     (unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT,
680 		     SET_MEMORY_RO | SET_MEMORY_X);
681 	__set_memory(__stext_amode31, (__etext_amode31 - __stext_amode31) >> PAGE_SHIFT,
682 		     SET_MEMORY_RO | SET_MEMORY_X);
683 
684 	/* lowcore requires 4k mapping for real addresses / prefixing */
685 	set_memory_4k(0, LC_PAGES);
686 
687 	/* lowcore must be executable for LPSWE */
688 	if (!static_key_enabled(&cpu_has_bear))
689 		set_memory_x(0, 1);
690 
691 	pr_info("Write protected kernel read-only data: %luk\n",
692 		(unsigned long)(__end_rodata - _stext) >> 10);
693 }
694