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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
22static DEFINE_MUTEX(vmem_mutex);
23
24static 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
33static 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
42void *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
52pte_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
67static 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 */
82static unsigned long unused_sub_pmd_start;
83
84static 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
93static 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
104static 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
120static 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. */
142static 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() */
152static 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;
187out:
188 if (direct)
189 update_page_count(PG_DIRECT_MAP_4K, add ? pages : -pages);
190 return ret;
191}
192
193static 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() */
209static 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;
284out:
285 if (direct)
286 update_page_count(PG_DIRECT_MAP_1M, add ? pages : -pages);
287 return ret;
288}
289
290static 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
311static 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;
359out:
360 if (direct)
361 update_page_count(PG_DIRECT_MAP_2G, add ? pages : -pages);
362 return ret;
363}
364
365static 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
388static 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;
415out:
416 return ret;
417}
418
419static 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
442static 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;
472out:
473 if (!add)
474 flush_tlb_kernel_range(start, end);
475 return ret;
476}
477
478static int add_pagetable(unsigned long start, unsigned long end, bool direct)
479{
480 return modify_pagetable(start, end, true, direct);
481}
482
483static 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 */
491static 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 */
499static 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 */
507int __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
521void 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
529void 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
536struct 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
545int 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 */
570pte_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);
620out:
621 return ptep;
622}
623
624int __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
639int 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
649void 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 */
665void __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}
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/ctlreg.h>
19#include <asm/pgalloc.h>
20#include <asm/setup.h>
21#include <asm/tlbflush.h>
22#include <asm/sections.h>
23#include <asm/set_memory.h>
24
25static DEFINE_MUTEX(vmem_mutex);
26
27static void __ref *vmem_alloc_pages(unsigned int order)
28{
29 unsigned long size = PAGE_SIZE << order;
30
31 if (slab_is_available())
32 return (void *)__get_free_pages(GFP_KERNEL, order);
33 return memblock_alloc(size, size);
34}
35
36static void vmem_free_pages(unsigned long addr, int order, struct vmem_altmap *altmap)
37{
38 if (altmap) {
39 vmem_altmap_free(altmap, 1 << order);
40 return;
41 }
42 /* We don't expect boot memory to be removed ever. */
43 if (!slab_is_available() ||
44 WARN_ON_ONCE(PageReserved(virt_to_page((void *)addr))))
45 return;
46 free_pages(addr, order);
47}
48
49void *vmem_crst_alloc(unsigned long val)
50{
51 unsigned long *table;
52
53 table = vmem_alloc_pages(CRST_ALLOC_ORDER);
54 if (!table)
55 return NULL;
56 crst_table_init(table, val);
57 __arch_set_page_dat(table, 1UL << CRST_ALLOC_ORDER);
58 return table;
59}
60
61pte_t __ref *vmem_pte_alloc(void)
62{
63 unsigned long size = PTRS_PER_PTE * sizeof(pte_t);
64 pte_t *pte;
65
66 if (slab_is_available())
67 pte = (pte_t *) page_table_alloc(&init_mm);
68 else
69 pte = (pte_t *) memblock_alloc(size, size);
70 if (!pte)
71 return NULL;
72 memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
73 __arch_set_page_dat(pte, 1);
74 return pte;
75}
76
77static void vmem_pte_free(unsigned long *table)
78{
79 /* We don't expect boot memory to be removed ever. */
80 if (!slab_is_available() ||
81 WARN_ON_ONCE(PageReserved(virt_to_page(table))))
82 return;
83 page_table_free(&init_mm, table);
84}
85
86#define PAGE_UNUSED 0xFD
87
88/*
89 * The unused vmemmap range, which was not yet memset(PAGE_UNUSED) ranges
90 * from unused_sub_pmd_start to next PMD_SIZE boundary.
91 */
92static unsigned long unused_sub_pmd_start;
93
94static void vmemmap_flush_unused_sub_pmd(void)
95{
96 if (!unused_sub_pmd_start)
97 return;
98 memset((void *)unused_sub_pmd_start, PAGE_UNUSED,
99 ALIGN(unused_sub_pmd_start, PMD_SIZE) - unused_sub_pmd_start);
100 unused_sub_pmd_start = 0;
101}
102
103static void vmemmap_mark_sub_pmd_used(unsigned long start, unsigned long end)
104{
105 /*
106 * As we expect to add in the same granularity as we remove, it's
107 * sufficient to mark only some piece used to block the memmap page from
108 * getting removed (just in case the memmap never gets initialized,
109 * e.g., because the memory block never gets onlined).
110 */
111 memset((void *)start, 0, sizeof(struct page));
112}
113
114static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end)
115{
116 /*
117 * We only optimize if the new used range directly follows the
118 * previously unused range (esp., when populating consecutive sections).
119 */
120 if (unused_sub_pmd_start == start) {
121 unused_sub_pmd_start = end;
122 if (likely(IS_ALIGNED(unused_sub_pmd_start, PMD_SIZE)))
123 unused_sub_pmd_start = 0;
124 return;
125 }
126 vmemmap_flush_unused_sub_pmd();
127 vmemmap_mark_sub_pmd_used(start, end);
128}
129
130static void vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end)
131{
132 unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
133
134 vmemmap_flush_unused_sub_pmd();
135
136 /* Could be our memmap page is filled with PAGE_UNUSED already ... */
137 vmemmap_mark_sub_pmd_used(start, end);
138
139 /* Mark the unused parts of the new memmap page PAGE_UNUSED. */
140 if (!IS_ALIGNED(start, PMD_SIZE))
141 memset((void *)page, PAGE_UNUSED, start - page);
142 /*
143 * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of
144 * consecutive sections. Remember for the last added PMD the last
145 * unused range in the populated PMD.
146 */
147 if (!IS_ALIGNED(end, PMD_SIZE))
148 unused_sub_pmd_start = end;
149}
150
151/* Returns true if the PMD is completely unused and can be freed. */
152static bool vmemmap_unuse_sub_pmd(unsigned long start, unsigned long end)
153{
154 unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
155
156 vmemmap_flush_unused_sub_pmd();
157 memset((void *)start, PAGE_UNUSED, end - start);
158 return !memchr_inv((void *)page, PAGE_UNUSED, PMD_SIZE);
159}
160
161/* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
162static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr,
163 unsigned long end, bool add, bool direct,
164 struct vmem_altmap *altmap)
165{
166 unsigned long prot, pages = 0;
167 int ret = -ENOMEM;
168 pte_t *pte;
169
170 prot = pgprot_val(PAGE_KERNEL);
171 if (!MACHINE_HAS_NX)
172 prot &= ~_PAGE_NOEXEC;
173
174 pte = pte_offset_kernel(pmd, addr);
175 for (; addr < end; addr += PAGE_SIZE, pte++) {
176 if (!add) {
177 if (pte_none(*pte))
178 continue;
179 if (!direct)
180 vmem_free_pages((unsigned long)pfn_to_virt(pte_pfn(*pte)), get_order(PAGE_SIZE), altmap);
181 pte_clear(&init_mm, addr, pte);
182 } else if (pte_none(*pte)) {
183 if (!direct) {
184 void *new_page = vmemmap_alloc_block_buf(PAGE_SIZE, NUMA_NO_NODE, altmap);
185
186 if (!new_page)
187 goto out;
188 set_pte(pte, __pte(__pa(new_page) | prot));
189 } else {
190 set_pte(pte, __pte(__pa(addr) | prot));
191 }
192 } else {
193 continue;
194 }
195 pages++;
196 }
197 ret = 0;
198out:
199 if (direct)
200 update_page_count(PG_DIRECT_MAP_4K, add ? pages : -pages);
201 return ret;
202}
203
204static void try_free_pte_table(pmd_t *pmd, unsigned long start)
205{
206 pte_t *pte;
207 int i;
208
209 /* We can safely assume this is fully in 1:1 mapping & vmemmap area */
210 pte = pte_offset_kernel(pmd, start);
211 for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
212 if (!pte_none(*pte))
213 return;
214 }
215 vmem_pte_free((unsigned long *) pmd_deref(*pmd));
216 pmd_clear(pmd);
217}
218
219/* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
220static int __ref modify_pmd_table(pud_t *pud, unsigned long addr,
221 unsigned long end, bool add, bool direct,
222 struct vmem_altmap *altmap)
223{
224 unsigned long next, prot, pages = 0;
225 int ret = -ENOMEM;
226 pmd_t *pmd;
227 pte_t *pte;
228
229 prot = pgprot_val(SEGMENT_KERNEL);
230 if (!MACHINE_HAS_NX)
231 prot &= ~_SEGMENT_ENTRY_NOEXEC;
232
233 pmd = pmd_offset(pud, addr);
234 for (; addr < end; addr = next, pmd++) {
235 next = pmd_addr_end(addr, end);
236 if (!add) {
237 if (pmd_none(*pmd))
238 continue;
239 if (pmd_leaf(*pmd)) {
240 if (IS_ALIGNED(addr, PMD_SIZE) &&
241 IS_ALIGNED(next, PMD_SIZE)) {
242 if (!direct)
243 vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE), altmap);
244 pmd_clear(pmd);
245 pages++;
246 } else if (!direct && vmemmap_unuse_sub_pmd(addr, next)) {
247 vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE), altmap);
248 pmd_clear(pmd);
249 }
250 continue;
251 }
252 } else if (pmd_none(*pmd)) {
253 if (IS_ALIGNED(addr, PMD_SIZE) &&
254 IS_ALIGNED(next, PMD_SIZE) &&
255 MACHINE_HAS_EDAT1 && direct &&
256 !debug_pagealloc_enabled()) {
257 set_pmd(pmd, __pmd(__pa(addr) | prot));
258 pages++;
259 continue;
260 } else if (!direct && MACHINE_HAS_EDAT1) {
261 void *new_page;
262
263 /*
264 * Use 1MB frames for vmemmap if available. We
265 * always use large frames even if they are only
266 * partially used. Otherwise we would have also
267 * page tables since vmemmap_populate gets
268 * called for each section separately.
269 */
270 new_page = vmemmap_alloc_block_buf(PMD_SIZE, NUMA_NO_NODE, altmap);
271 if (new_page) {
272 set_pmd(pmd, __pmd(__pa(new_page) | prot));
273 if (!IS_ALIGNED(addr, PMD_SIZE) ||
274 !IS_ALIGNED(next, PMD_SIZE)) {
275 vmemmap_use_new_sub_pmd(addr, next);
276 }
277 continue;
278 }
279 }
280 pte = vmem_pte_alloc();
281 if (!pte)
282 goto out;
283 pmd_populate(&init_mm, pmd, pte);
284 } else if (pmd_leaf(*pmd)) {
285 if (!direct)
286 vmemmap_use_sub_pmd(addr, next);
287 continue;
288 }
289 ret = modify_pte_table(pmd, addr, next, add, direct, altmap);
290 if (ret)
291 goto out;
292 if (!add)
293 try_free_pte_table(pmd, addr & PMD_MASK);
294 }
295 ret = 0;
296out:
297 if (direct)
298 update_page_count(PG_DIRECT_MAP_1M, add ? pages : -pages);
299 return ret;
300}
301
302static void try_free_pmd_table(pud_t *pud, unsigned long start)
303{
304 pmd_t *pmd;
305 int i;
306
307 pmd = pmd_offset(pud, start);
308 for (i = 0; i < PTRS_PER_PMD; i++, pmd++)
309 if (!pmd_none(*pmd))
310 return;
311 vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER, NULL);
312 pud_clear(pud);
313}
314
315static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end,
316 bool add, bool direct, struct vmem_altmap *altmap)
317{
318 unsigned long next, prot, pages = 0;
319 int ret = -ENOMEM;
320 pud_t *pud;
321 pmd_t *pmd;
322
323 prot = pgprot_val(REGION3_KERNEL);
324 if (!MACHINE_HAS_NX)
325 prot &= ~_REGION_ENTRY_NOEXEC;
326 pud = pud_offset(p4d, addr);
327 for (; addr < end; addr = next, pud++) {
328 next = pud_addr_end(addr, end);
329 if (!add) {
330 if (pud_none(*pud))
331 continue;
332 if (pud_leaf(*pud)) {
333 if (IS_ALIGNED(addr, PUD_SIZE) &&
334 IS_ALIGNED(next, PUD_SIZE)) {
335 pud_clear(pud);
336 pages++;
337 }
338 continue;
339 }
340 } else if (pud_none(*pud)) {
341 if (IS_ALIGNED(addr, PUD_SIZE) &&
342 IS_ALIGNED(next, PUD_SIZE) &&
343 MACHINE_HAS_EDAT2 && direct &&
344 !debug_pagealloc_enabled()) {
345 set_pud(pud, __pud(__pa(addr) | prot));
346 pages++;
347 continue;
348 }
349 pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
350 if (!pmd)
351 goto out;
352 pud_populate(&init_mm, pud, pmd);
353 } else if (pud_leaf(*pud)) {
354 continue;
355 }
356 ret = modify_pmd_table(pud, addr, next, add, direct, altmap);
357 if (ret)
358 goto out;
359 if (!add)
360 try_free_pmd_table(pud, addr & PUD_MASK);
361 }
362 ret = 0;
363out:
364 if (direct)
365 update_page_count(PG_DIRECT_MAP_2G, add ? pages : -pages);
366 return ret;
367}
368
369static void try_free_pud_table(p4d_t *p4d, unsigned long start)
370{
371 pud_t *pud;
372 int i;
373
374 pud = pud_offset(p4d, start);
375 for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
376 if (!pud_none(*pud))
377 return;
378 }
379 vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER, NULL);
380 p4d_clear(p4d);
381}
382
383static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end,
384 bool add, bool direct, struct vmem_altmap *altmap)
385{
386 unsigned long next;
387 int ret = -ENOMEM;
388 p4d_t *p4d;
389 pud_t *pud;
390
391 p4d = p4d_offset(pgd, addr);
392 for (; addr < end; addr = next, p4d++) {
393 next = p4d_addr_end(addr, end);
394 if (!add) {
395 if (p4d_none(*p4d))
396 continue;
397 } else if (p4d_none(*p4d)) {
398 pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
399 if (!pud)
400 goto out;
401 p4d_populate(&init_mm, p4d, pud);
402 }
403 ret = modify_pud_table(p4d, addr, next, add, direct, altmap);
404 if (ret)
405 goto out;
406 if (!add)
407 try_free_pud_table(p4d, addr & P4D_MASK);
408 }
409 ret = 0;
410out:
411 return ret;
412}
413
414static void try_free_p4d_table(pgd_t *pgd, unsigned long start)
415{
416 p4d_t *p4d;
417 int i;
418
419 p4d = p4d_offset(pgd, start);
420 for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
421 if (!p4d_none(*p4d))
422 return;
423 }
424 vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER, NULL);
425 pgd_clear(pgd);
426}
427
428static int modify_pagetable(unsigned long start, unsigned long end, bool add,
429 bool direct, struct vmem_altmap *altmap)
430{
431 unsigned long addr, next;
432 int ret = -ENOMEM;
433 pgd_t *pgd;
434 p4d_t *p4d;
435
436 if (WARN_ON_ONCE(!PAGE_ALIGNED(start | end)))
437 return -EINVAL;
438 /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
439 if (WARN_ON_ONCE(end > VMALLOC_START))
440 return -EINVAL;
441 for (addr = start; addr < end; addr = next) {
442 next = pgd_addr_end(addr, end);
443 pgd = pgd_offset_k(addr);
444
445 if (!add) {
446 if (pgd_none(*pgd))
447 continue;
448 } else if (pgd_none(*pgd)) {
449 p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
450 if (!p4d)
451 goto out;
452 pgd_populate(&init_mm, pgd, p4d);
453 }
454 ret = modify_p4d_table(pgd, addr, next, add, direct, altmap);
455 if (ret)
456 goto out;
457 if (!add)
458 try_free_p4d_table(pgd, addr & PGDIR_MASK);
459 }
460 ret = 0;
461out:
462 if (!add)
463 flush_tlb_kernel_range(start, end);
464 return ret;
465}
466
467static int add_pagetable(unsigned long start, unsigned long end, bool direct,
468 struct vmem_altmap *altmap)
469{
470 return modify_pagetable(start, end, true, direct, altmap);
471}
472
473static int remove_pagetable(unsigned long start, unsigned long end, bool direct,
474 struct vmem_altmap *altmap)
475{
476 return modify_pagetable(start, end, false, direct, altmap);
477}
478
479/*
480 * Add a physical memory range to the 1:1 mapping.
481 */
482static int vmem_add_range(unsigned long start, unsigned long size)
483{
484 start = (unsigned long)__va(start);
485 return add_pagetable(start, start + size, true, NULL);
486}
487
488/*
489 * Remove a physical memory range from the 1:1 mapping.
490 */
491static void vmem_remove_range(unsigned long start, unsigned long size)
492{
493 start = (unsigned long)__va(start);
494 remove_pagetable(start, start + size, true, NULL);
495}
496
497/*
498 * Add a backed mem_map array to the virtual mem_map array.
499 */
500int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
501 struct vmem_altmap *altmap)
502{
503 int ret;
504
505 mutex_lock(&vmem_mutex);
506 /* We don't care about the node, just use NUMA_NO_NODE on allocations */
507 ret = add_pagetable(start, end, false, altmap);
508 if (ret)
509 remove_pagetable(start, end, false, altmap);
510 mutex_unlock(&vmem_mutex);
511 return ret;
512}
513
514#ifdef CONFIG_MEMORY_HOTPLUG
515
516void vmemmap_free(unsigned long start, unsigned long end,
517 struct vmem_altmap *altmap)
518{
519 mutex_lock(&vmem_mutex);
520 remove_pagetable(start, end, false, altmap);
521 mutex_unlock(&vmem_mutex);
522}
523
524#endif
525
526void vmem_remove_mapping(unsigned long start, unsigned long size)
527{
528 mutex_lock(&vmem_mutex);
529 vmem_remove_range(start, size);
530 mutex_unlock(&vmem_mutex);
531}
532
533struct range arch_get_mappable_range(void)
534{
535 struct range mhp_range;
536
537 mhp_range.start = 0;
538 mhp_range.end = max_mappable - 1;
539 return mhp_range;
540}
541
542int vmem_add_mapping(unsigned long start, unsigned long size)
543{
544 struct range range = arch_get_mappable_range();
545 int ret;
546
547 if (start < range.start ||
548 start + size > range.end + 1 ||
549 start + size < start)
550 return -ERANGE;
551
552 mutex_lock(&vmem_mutex);
553 ret = vmem_add_range(start, size);
554 if (ret)
555 vmem_remove_range(start, size);
556 mutex_unlock(&vmem_mutex);
557 return ret;
558}
559
560/*
561 * Allocate new or return existing page-table entry, but do not map it
562 * to any physical address. If missing, allocate segment- and region-
563 * table entries along. Meeting a large segment- or region-table entry
564 * while traversing is an error, since the function is expected to be
565 * called against virtual regions reserved for 4KB mappings only.
566 */
567pte_t *vmem_get_alloc_pte(unsigned long addr, bool alloc)
568{
569 pte_t *ptep = NULL;
570 pgd_t *pgd;
571 p4d_t *p4d;
572 pud_t *pud;
573 pmd_t *pmd;
574 pte_t *pte;
575
576 pgd = pgd_offset_k(addr);
577 if (pgd_none(*pgd)) {
578 if (!alloc)
579 goto out;
580 p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
581 if (!p4d)
582 goto out;
583 pgd_populate(&init_mm, pgd, p4d);
584 }
585 p4d = p4d_offset(pgd, addr);
586 if (p4d_none(*p4d)) {
587 if (!alloc)
588 goto out;
589 pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
590 if (!pud)
591 goto out;
592 p4d_populate(&init_mm, p4d, pud);
593 }
594 pud = pud_offset(p4d, addr);
595 if (pud_none(*pud)) {
596 if (!alloc)
597 goto out;
598 pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
599 if (!pmd)
600 goto out;
601 pud_populate(&init_mm, pud, pmd);
602 } else if (WARN_ON_ONCE(pud_leaf(*pud))) {
603 goto out;
604 }
605 pmd = pmd_offset(pud, addr);
606 if (pmd_none(*pmd)) {
607 if (!alloc)
608 goto out;
609 pte = vmem_pte_alloc();
610 if (!pte)
611 goto out;
612 pmd_populate(&init_mm, pmd, pte);
613 } else if (WARN_ON_ONCE(pmd_leaf(*pmd))) {
614 goto out;
615 }
616 ptep = pte_offset_kernel(pmd, addr);
617out:
618 return ptep;
619}
620
621int __vmem_map_4k_page(unsigned long addr, unsigned long phys, pgprot_t prot, bool alloc)
622{
623 pte_t *ptep, pte;
624
625 if (!IS_ALIGNED(addr, PAGE_SIZE))
626 return -EINVAL;
627 ptep = vmem_get_alloc_pte(addr, alloc);
628 if (!ptep)
629 return -ENOMEM;
630 __ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
631 pte = mk_pte_phys(phys, prot);
632 set_pte(ptep, pte);
633 return 0;
634}
635
636int vmem_map_4k_page(unsigned long addr, unsigned long phys, pgprot_t prot)
637{
638 int rc;
639
640 mutex_lock(&vmem_mutex);
641 rc = __vmem_map_4k_page(addr, phys, prot, true);
642 mutex_unlock(&vmem_mutex);
643 return rc;
644}
645
646void vmem_unmap_4k_page(unsigned long addr)
647{
648 pte_t *ptep;
649
650 mutex_lock(&vmem_mutex);
651 ptep = virt_to_kpte(addr);
652 __ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
653 pte_clear(&init_mm, addr, ptep);
654 mutex_unlock(&vmem_mutex);
655}
656
657void __init vmem_map_init(void)
658{
659 __set_memory_rox(_stext, _etext);
660 __set_memory_ro(_etext, __end_rodata);
661 __set_memory_rox(_sinittext, _einittext);
662 __set_memory_rox(__stext_amode31, __etext_amode31);
663 /*
664 * If the BEAR-enhancement facility is not installed the first
665 * prefix page is used to return to the previous context with
666 * an LPSWE instruction and therefore must be executable.
667 */
668 if (!static_key_enabled(&cpu_has_bear))
669 set_memory_x(0, 1);
670 if (debug_pagealloc_enabled()) {
671 /*
672 * Use RELOC_HIDE() as long as __va(0) translates to NULL,
673 * since performing pointer arithmetic on a NULL pointer
674 * has undefined behavior and generates compiler warnings.
675 */
676 __set_memory_4k(__va(0), RELOC_HIDE(__va(0), ident_map_size));
677 }
678 if (MACHINE_HAS_NX)
679 system_ctl_set_bit(0, CR0_INSTRUCTION_EXEC_PROTECTION_BIT);
680 pr_info("Write protected kernel read-only data: %luk\n",
681 (unsigned long)(__end_rodata - _stext) >> 10);
682}