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