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1// SPDX-License-Identifier: GPL-2.0
2#include <linux/mm.h>
3#include <linux/gfp.h>
4#include <linux/hugetlb.h>
5#include <asm/pgalloc.h>
6#include <asm/tlb.h>
7#include <asm/fixmap.h>
8#include <asm/mtrr.h>
9
10#ifdef CONFIG_DYNAMIC_PHYSICAL_MASK
11phys_addr_t physical_mask __ro_after_init = (1ULL << __PHYSICAL_MASK_SHIFT) - 1;
12EXPORT_SYMBOL(physical_mask);
13#endif
14
15#ifdef CONFIG_HIGHPTE
16#define PGTABLE_HIGHMEM __GFP_HIGHMEM
17#else
18#define PGTABLE_HIGHMEM 0
19#endif
20
21#ifndef CONFIG_PARAVIRT
22static inline
23void paravirt_tlb_remove_table(struct mmu_gather *tlb, void *table)
24{
25 tlb_remove_page(tlb, table);
26}
27#endif
28
29gfp_t __userpte_alloc_gfp = GFP_PGTABLE_USER | PGTABLE_HIGHMEM;
30
31pgtable_t pte_alloc_one(struct mm_struct *mm)
32{
33 return __pte_alloc_one(mm, __userpte_alloc_gfp);
34}
35
36static int __init setup_userpte(char *arg)
37{
38 if (!arg)
39 return -EINVAL;
40
41 /*
42 * "userpte=nohigh" disables allocation of user pagetables in
43 * high memory.
44 */
45 if (strcmp(arg, "nohigh") == 0)
46 __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
47 else
48 return -EINVAL;
49 return 0;
50}
51early_param("userpte", setup_userpte);
52
53void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
54{
55 pgtable_pte_page_dtor(pte);
56 paravirt_release_pte(page_to_pfn(pte));
57 paravirt_tlb_remove_table(tlb, pte);
58}
59
60#if CONFIG_PGTABLE_LEVELS > 2
61void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
62{
63 struct page *page = virt_to_page(pmd);
64 paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
65 /*
66 * NOTE! For PAE, any changes to the top page-directory-pointer-table
67 * entries need a full cr3 reload to flush.
68 */
69#ifdef CONFIG_X86_PAE
70 tlb->need_flush_all = 1;
71#endif
72 pgtable_pmd_page_dtor(page);
73 paravirt_tlb_remove_table(tlb, page);
74}
75
76#if CONFIG_PGTABLE_LEVELS > 3
77void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
78{
79 paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
80 paravirt_tlb_remove_table(tlb, virt_to_page(pud));
81}
82
83#if CONFIG_PGTABLE_LEVELS > 4
84void ___p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d)
85{
86 paravirt_release_p4d(__pa(p4d) >> PAGE_SHIFT);
87 paravirt_tlb_remove_table(tlb, virt_to_page(p4d));
88}
89#endif /* CONFIG_PGTABLE_LEVELS > 4 */
90#endif /* CONFIG_PGTABLE_LEVELS > 3 */
91#endif /* CONFIG_PGTABLE_LEVELS > 2 */
92
93static inline void pgd_list_add(pgd_t *pgd)
94{
95 struct page *page = virt_to_page(pgd);
96
97 list_add(&page->lru, &pgd_list);
98}
99
100static inline void pgd_list_del(pgd_t *pgd)
101{
102 struct page *page = virt_to_page(pgd);
103
104 list_del(&page->lru);
105}
106
107#define UNSHARED_PTRS_PER_PGD \
108 (SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
109#define MAX_UNSHARED_PTRS_PER_PGD \
110 max_t(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD)
111
112
113static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
114{
115 virt_to_page(pgd)->pt_mm = mm;
116}
117
118struct mm_struct *pgd_page_get_mm(struct page *page)
119{
120 return page->pt_mm;
121}
122
123static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
124{
125 /* If the pgd points to a shared pagetable level (either the
126 ptes in non-PAE, or shared PMD in PAE), then just copy the
127 references from swapper_pg_dir. */
128 if (CONFIG_PGTABLE_LEVELS == 2 ||
129 (CONFIG_PGTABLE_LEVELS == 3 && SHARED_KERNEL_PMD) ||
130 CONFIG_PGTABLE_LEVELS >= 4) {
131 clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY,
132 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
133 KERNEL_PGD_PTRS);
134 }
135
136 /* list required to sync kernel mapping updates */
137 if (!SHARED_KERNEL_PMD) {
138 pgd_set_mm(pgd, mm);
139 pgd_list_add(pgd);
140 }
141}
142
143static void pgd_dtor(pgd_t *pgd)
144{
145 if (SHARED_KERNEL_PMD)
146 return;
147
148 spin_lock(&pgd_lock);
149 pgd_list_del(pgd);
150 spin_unlock(&pgd_lock);
151}
152
153/*
154 * List of all pgd's needed for non-PAE so it can invalidate entries
155 * in both cached and uncached pgd's; not needed for PAE since the
156 * kernel pmd is shared. If PAE were not to share the pmd a similar
157 * tactic would be needed. This is essentially codepath-based locking
158 * against pageattr.c; it is the unique case in which a valid change
159 * of kernel pagetables can't be lazily synchronized by vmalloc faults.
160 * vmalloc faults work because attached pagetables are never freed.
161 * -- nyc
162 */
163
164#ifdef CONFIG_X86_PAE
165/*
166 * In PAE mode, we need to do a cr3 reload (=tlb flush) when
167 * updating the top-level pagetable entries to guarantee the
168 * processor notices the update. Since this is expensive, and
169 * all 4 top-level entries are used almost immediately in a
170 * new process's life, we just pre-populate them here.
171 *
172 * Also, if we're in a paravirt environment where the kernel pmd is
173 * not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate
174 * and initialize the kernel pmds here.
175 */
176#define PREALLOCATED_PMDS UNSHARED_PTRS_PER_PGD
177#define MAX_PREALLOCATED_PMDS MAX_UNSHARED_PTRS_PER_PGD
178
179/*
180 * We allocate separate PMDs for the kernel part of the user page-table
181 * when PTI is enabled. We need them to map the per-process LDT into the
182 * user-space page-table.
183 */
184#define PREALLOCATED_USER_PMDS (boot_cpu_has(X86_FEATURE_PTI) ? \
185 KERNEL_PGD_PTRS : 0)
186#define MAX_PREALLOCATED_USER_PMDS KERNEL_PGD_PTRS
187
188void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
189{
190 paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT);
191
192 /* Note: almost everything apart from _PAGE_PRESENT is
193 reserved at the pmd (PDPT) level. */
194 set_pud(pudp, __pud(__pa(pmd) | _PAGE_PRESENT));
195
196 /*
197 * According to Intel App note "TLBs, Paging-Structure Caches,
198 * and Their Invalidation", April 2007, document 317080-001,
199 * section 8.1: in PAE mode we explicitly have to flush the
200 * TLB via cr3 if the top-level pgd is changed...
201 */
202 flush_tlb_mm(mm);
203}
204#else /* !CONFIG_X86_PAE */
205
206/* No need to prepopulate any pagetable entries in non-PAE modes. */
207#define PREALLOCATED_PMDS 0
208#define MAX_PREALLOCATED_PMDS 0
209#define PREALLOCATED_USER_PMDS 0
210#define MAX_PREALLOCATED_USER_PMDS 0
211#endif /* CONFIG_X86_PAE */
212
213static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
214{
215 int i;
216
217 for (i = 0; i < count; i++)
218 if (pmds[i]) {
219 pgtable_pmd_page_dtor(virt_to_page(pmds[i]));
220 free_page((unsigned long)pmds[i]);
221 mm_dec_nr_pmds(mm);
222 }
223}
224
225static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
226{
227 int i;
228 bool failed = false;
229 gfp_t gfp = GFP_PGTABLE_USER;
230
231 if (mm == &init_mm)
232 gfp &= ~__GFP_ACCOUNT;
233
234 for (i = 0; i < count; i++) {
235 pmd_t *pmd = (pmd_t *)__get_free_page(gfp);
236 if (!pmd)
237 failed = true;
238 if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
239 free_page((unsigned long)pmd);
240 pmd = NULL;
241 failed = true;
242 }
243 if (pmd)
244 mm_inc_nr_pmds(mm);
245 pmds[i] = pmd;
246 }
247
248 if (failed) {
249 free_pmds(mm, pmds, count);
250 return -ENOMEM;
251 }
252
253 return 0;
254}
255
256/*
257 * Mop up any pmd pages which may still be attached to the pgd.
258 * Normally they will be freed by munmap/exit_mmap, but any pmd we
259 * preallocate which never got a corresponding vma will need to be
260 * freed manually.
261 */
262static void mop_up_one_pmd(struct mm_struct *mm, pgd_t *pgdp)
263{
264 pgd_t pgd = *pgdp;
265
266 if (pgd_val(pgd) != 0) {
267 pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
268
269 pgd_clear(pgdp);
270
271 paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT);
272 pmd_free(mm, pmd);
273 mm_dec_nr_pmds(mm);
274 }
275}
276
277static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
278{
279 int i;
280
281 for (i = 0; i < PREALLOCATED_PMDS; i++)
282 mop_up_one_pmd(mm, &pgdp[i]);
283
284#ifdef CONFIG_PAGE_TABLE_ISOLATION
285
286 if (!boot_cpu_has(X86_FEATURE_PTI))
287 return;
288
289 pgdp = kernel_to_user_pgdp(pgdp);
290
291 for (i = 0; i < PREALLOCATED_USER_PMDS; i++)
292 mop_up_one_pmd(mm, &pgdp[i + KERNEL_PGD_BOUNDARY]);
293#endif
294}
295
296static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
297{
298 p4d_t *p4d;
299 pud_t *pud;
300 int i;
301
302 p4d = p4d_offset(pgd, 0);
303 pud = pud_offset(p4d, 0);
304
305 for (i = 0; i < PREALLOCATED_PMDS; i++, pud++) {
306 pmd_t *pmd = pmds[i];
307
308 if (i >= KERNEL_PGD_BOUNDARY)
309 memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]),
310 sizeof(pmd_t) * PTRS_PER_PMD);
311
312 pud_populate(mm, pud, pmd);
313 }
314}
315
316#ifdef CONFIG_PAGE_TABLE_ISOLATION
317static void pgd_prepopulate_user_pmd(struct mm_struct *mm,
318 pgd_t *k_pgd, pmd_t *pmds[])
319{
320 pgd_t *s_pgd = kernel_to_user_pgdp(swapper_pg_dir);
321 pgd_t *u_pgd = kernel_to_user_pgdp(k_pgd);
322 p4d_t *u_p4d;
323 pud_t *u_pud;
324 int i;
325
326 u_p4d = p4d_offset(u_pgd, 0);
327 u_pud = pud_offset(u_p4d, 0);
328
329 s_pgd += KERNEL_PGD_BOUNDARY;
330 u_pud += KERNEL_PGD_BOUNDARY;
331
332 for (i = 0; i < PREALLOCATED_USER_PMDS; i++, u_pud++, s_pgd++) {
333 pmd_t *pmd = pmds[i];
334
335 memcpy(pmd, (pmd_t *)pgd_page_vaddr(*s_pgd),
336 sizeof(pmd_t) * PTRS_PER_PMD);
337
338 pud_populate(mm, u_pud, pmd);
339 }
340
341}
342#else
343static void pgd_prepopulate_user_pmd(struct mm_struct *mm,
344 pgd_t *k_pgd, pmd_t *pmds[])
345{
346}
347#endif
348/*
349 * Xen paravirt assumes pgd table should be in one page. 64 bit kernel also
350 * assumes that pgd should be in one page.
351 *
352 * But kernel with PAE paging that is not running as a Xen domain
353 * only needs to allocate 32 bytes for pgd instead of one page.
354 */
355#ifdef CONFIG_X86_PAE
356
357#include <linux/slab.h>
358
359#define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t))
360#define PGD_ALIGN 32
361
362static struct kmem_cache *pgd_cache;
363
364void __init pgtable_cache_init(void)
365{
366 /*
367 * When PAE kernel is running as a Xen domain, it does not use
368 * shared kernel pmd. And this requires a whole page for pgd.
369 */
370 if (!SHARED_KERNEL_PMD)
371 return;
372
373 /*
374 * when PAE kernel is not running as a Xen domain, it uses
375 * shared kernel pmd. Shared kernel pmd does not require a whole
376 * page for pgd. We are able to just allocate a 32-byte for pgd.
377 * During boot time, we create a 32-byte slab for pgd table allocation.
378 */
379 pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_ALIGN,
380 SLAB_PANIC, NULL);
381}
382
383static inline pgd_t *_pgd_alloc(void)
384{
385 /*
386 * If no SHARED_KERNEL_PMD, PAE kernel is running as a Xen domain.
387 * We allocate one page for pgd.
388 */
389 if (!SHARED_KERNEL_PMD)
390 return (pgd_t *)__get_free_pages(GFP_PGTABLE_USER,
391 PGD_ALLOCATION_ORDER);
392
393 /*
394 * Now PAE kernel is not running as a Xen domain. We can allocate
395 * a 32-byte slab for pgd to save memory space.
396 */
397 return kmem_cache_alloc(pgd_cache, GFP_PGTABLE_USER);
398}
399
400static inline void _pgd_free(pgd_t *pgd)
401{
402 if (!SHARED_KERNEL_PMD)
403 free_pages((unsigned long)pgd, PGD_ALLOCATION_ORDER);
404 else
405 kmem_cache_free(pgd_cache, pgd);
406}
407#else
408
409static inline pgd_t *_pgd_alloc(void)
410{
411 return (pgd_t *)__get_free_pages(GFP_PGTABLE_USER,
412 PGD_ALLOCATION_ORDER);
413}
414
415static inline void _pgd_free(pgd_t *pgd)
416{
417 free_pages((unsigned long)pgd, PGD_ALLOCATION_ORDER);
418}
419#endif /* CONFIG_X86_PAE */
420
421pgd_t *pgd_alloc(struct mm_struct *mm)
422{
423 pgd_t *pgd;
424 pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS];
425 pmd_t *pmds[MAX_PREALLOCATED_PMDS];
426
427 pgd = _pgd_alloc();
428
429 if (pgd == NULL)
430 goto out;
431
432 mm->pgd = pgd;
433
434 if (sizeof(pmds) != 0 &&
435 preallocate_pmds(mm, pmds, PREALLOCATED_PMDS) != 0)
436 goto out_free_pgd;
437
438 if (sizeof(u_pmds) != 0 &&
439 preallocate_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS) != 0)
440 goto out_free_pmds;
441
442 if (paravirt_pgd_alloc(mm) != 0)
443 goto out_free_user_pmds;
444
445 /*
446 * Make sure that pre-populating the pmds is atomic with
447 * respect to anything walking the pgd_list, so that they
448 * never see a partially populated pgd.
449 */
450 spin_lock(&pgd_lock);
451
452 pgd_ctor(mm, pgd);
453 if (sizeof(pmds) != 0)
454 pgd_prepopulate_pmd(mm, pgd, pmds);
455
456 if (sizeof(u_pmds) != 0)
457 pgd_prepopulate_user_pmd(mm, pgd, u_pmds);
458
459 spin_unlock(&pgd_lock);
460
461 return pgd;
462
463out_free_user_pmds:
464 if (sizeof(u_pmds) != 0)
465 free_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS);
466out_free_pmds:
467 if (sizeof(pmds) != 0)
468 free_pmds(mm, pmds, PREALLOCATED_PMDS);
469out_free_pgd:
470 _pgd_free(pgd);
471out:
472 return NULL;
473}
474
475void pgd_free(struct mm_struct *mm, pgd_t *pgd)
476{
477 pgd_mop_up_pmds(mm, pgd);
478 pgd_dtor(pgd);
479 paravirt_pgd_free(mm, pgd);
480 _pgd_free(pgd);
481}
482
483/*
484 * Used to set accessed or dirty bits in the page table entries
485 * on other architectures. On x86, the accessed and dirty bits
486 * are tracked by hardware. However, do_wp_page calls this function
487 * to also make the pte writeable at the same time the dirty bit is
488 * set. In that case we do actually need to write the PTE.
489 */
490int ptep_set_access_flags(struct vm_area_struct *vma,
491 unsigned long address, pte_t *ptep,
492 pte_t entry, int dirty)
493{
494 int changed = !pte_same(*ptep, entry);
495
496 if (changed && dirty)
497 set_pte(ptep, entry);
498
499 return changed;
500}
501
502#ifdef CONFIG_TRANSPARENT_HUGEPAGE
503int pmdp_set_access_flags(struct vm_area_struct *vma,
504 unsigned long address, pmd_t *pmdp,
505 pmd_t entry, int dirty)
506{
507 int changed = !pmd_same(*pmdp, entry);
508
509 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
510
511 if (changed && dirty) {
512 set_pmd(pmdp, entry);
513 /*
514 * We had a write-protection fault here and changed the pmd
515 * to to more permissive. No need to flush the TLB for that,
516 * #PF is architecturally guaranteed to do that and in the
517 * worst-case we'll generate a spurious fault.
518 */
519 }
520
521 return changed;
522}
523
524int pudp_set_access_flags(struct vm_area_struct *vma, unsigned long address,
525 pud_t *pudp, pud_t entry, int dirty)
526{
527 int changed = !pud_same(*pudp, entry);
528
529 VM_BUG_ON(address & ~HPAGE_PUD_MASK);
530
531 if (changed && dirty) {
532 set_pud(pudp, entry);
533 /*
534 * We had a write-protection fault here and changed the pud
535 * to to more permissive. No need to flush the TLB for that,
536 * #PF is architecturally guaranteed to do that and in the
537 * worst-case we'll generate a spurious fault.
538 */
539 }
540
541 return changed;
542}
543#endif
544
545int ptep_test_and_clear_young(struct vm_area_struct *vma,
546 unsigned long addr, pte_t *ptep)
547{
548 int ret = 0;
549
550 if (pte_young(*ptep))
551 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
552 (unsigned long *) &ptep->pte);
553
554 return ret;
555}
556
557#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG)
558int pmdp_test_and_clear_young(struct vm_area_struct *vma,
559 unsigned long addr, pmd_t *pmdp)
560{
561 int ret = 0;
562
563 if (pmd_young(*pmdp))
564 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
565 (unsigned long *)pmdp);
566
567 return ret;
568}
569#endif
570
571#ifdef CONFIG_TRANSPARENT_HUGEPAGE
572int pudp_test_and_clear_young(struct vm_area_struct *vma,
573 unsigned long addr, pud_t *pudp)
574{
575 int ret = 0;
576
577 if (pud_young(*pudp))
578 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
579 (unsigned long *)pudp);
580
581 return ret;
582}
583#endif
584
585int ptep_clear_flush_young(struct vm_area_struct *vma,
586 unsigned long address, pte_t *ptep)
587{
588 /*
589 * On x86 CPUs, clearing the accessed bit without a TLB flush
590 * doesn't cause data corruption. [ It could cause incorrect
591 * page aging and the (mistaken) reclaim of hot pages, but the
592 * chance of that should be relatively low. ]
593 *
594 * So as a performance optimization don't flush the TLB when
595 * clearing the accessed bit, it will eventually be flushed by
596 * a context switch or a VM operation anyway. [ In the rare
597 * event of it not getting flushed for a long time the delay
598 * shouldn't really matter because there's no real memory
599 * pressure for swapout to react to. ]
600 */
601 return ptep_test_and_clear_young(vma, address, ptep);
602}
603
604#ifdef CONFIG_TRANSPARENT_HUGEPAGE
605int pmdp_clear_flush_young(struct vm_area_struct *vma,
606 unsigned long address, pmd_t *pmdp)
607{
608 int young;
609
610 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
611
612 young = pmdp_test_and_clear_young(vma, address, pmdp);
613 if (young)
614 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
615
616 return young;
617}
618
619pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
620 pmd_t *pmdp)
621{
622 /*
623 * No flush is necessary. Once an invalid PTE is established, the PTE's
624 * access and dirty bits cannot be updated.
625 */
626 return pmdp_establish(vma, address, pmdp, pmd_mkinvalid(*pmdp));
627}
628#endif
629
630/**
631 * reserve_top_address - reserves a hole in the top of kernel address space
632 * @reserve - size of hole to reserve
633 *
634 * Can be used to relocate the fixmap area and poke a hole in the top
635 * of kernel address space to make room for a hypervisor.
636 */
637void __init reserve_top_address(unsigned long reserve)
638{
639#ifdef CONFIG_X86_32
640 BUG_ON(fixmaps_set > 0);
641 __FIXADDR_TOP = round_down(-reserve, 1 << PMD_SHIFT) - PAGE_SIZE;
642 printk(KERN_INFO "Reserving virtual address space above 0x%08lx (rounded to 0x%08lx)\n",
643 -reserve, __FIXADDR_TOP + PAGE_SIZE);
644#endif
645}
646
647int fixmaps_set;
648
649void __native_set_fixmap(enum fixed_addresses idx, pte_t pte)
650{
651 unsigned long address = __fix_to_virt(idx);
652
653#ifdef CONFIG_X86_64
654 /*
655 * Ensure that the static initial page tables are covering the
656 * fixmap completely.
657 */
658 BUILD_BUG_ON(__end_of_permanent_fixed_addresses >
659 (FIXMAP_PMD_NUM * PTRS_PER_PTE));
660#endif
661
662 if (idx >= __end_of_fixed_addresses) {
663 BUG();
664 return;
665 }
666 set_pte_vaddr(address, pte);
667 fixmaps_set++;
668}
669
670void native_set_fixmap(unsigned /* enum fixed_addresses */ idx,
671 phys_addr_t phys, pgprot_t flags)
672{
673 /* Sanitize 'prot' against any unsupported bits: */
674 pgprot_val(flags) &= __default_kernel_pte_mask;
675
676 __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags));
677}
678
679#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
680#ifdef CONFIG_X86_5LEVEL
681/**
682 * p4d_set_huge - setup kernel P4D mapping
683 *
684 * No 512GB pages yet -- always return 0
685 */
686int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
687{
688 return 0;
689}
690
691/**
692 * p4d_clear_huge - clear kernel P4D mapping when it is set
693 *
694 * No 512GB pages yet -- always return 0
695 */
696void p4d_clear_huge(p4d_t *p4d)
697{
698}
699#endif
700
701/**
702 * pud_set_huge - setup kernel PUD mapping
703 *
704 * MTRRs can override PAT memory types with 4KiB granularity. Therefore, this
705 * function sets up a huge page only if any of the following conditions are met:
706 *
707 * - MTRRs are disabled, or
708 *
709 * - MTRRs are enabled and the range is completely covered by a single MTRR, or
710 *
711 * - MTRRs are enabled and the corresponding MTRR memory type is WB, which
712 * has no effect on the requested PAT memory type.
713 *
714 * Callers should try to decrease page size (1GB -> 2MB -> 4K) if the bigger
715 * page mapping attempt fails.
716 *
717 * Returns 1 on success and 0 on failure.
718 */
719int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
720{
721 u8 mtrr, uniform;
722
723 mtrr = mtrr_type_lookup(addr, addr + PUD_SIZE, &uniform);
724 if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) &&
725 (mtrr != MTRR_TYPE_WRBACK))
726 return 0;
727
728 /* Bail out if we are we on a populated non-leaf entry: */
729 if (pud_present(*pud) && !pud_huge(*pud))
730 return 0;
731
732 set_pte((pte_t *)pud, pfn_pte(
733 (u64)addr >> PAGE_SHIFT,
734 __pgprot(protval_4k_2_large(pgprot_val(prot)) | _PAGE_PSE)));
735
736 return 1;
737}
738
739/**
740 * pmd_set_huge - setup kernel PMD mapping
741 *
742 * See text over pud_set_huge() above.
743 *
744 * Returns 1 on success and 0 on failure.
745 */
746int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
747{
748 u8 mtrr, uniform;
749
750 mtrr = mtrr_type_lookup(addr, addr + PMD_SIZE, &uniform);
751 if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) &&
752 (mtrr != MTRR_TYPE_WRBACK)) {
753 pr_warn_once("%s: Cannot satisfy [mem %#010llx-%#010llx] with a huge-page mapping due to MTRR override.\n",
754 __func__, addr, addr + PMD_SIZE);
755 return 0;
756 }
757
758 /* Bail out if we are we on a populated non-leaf entry: */
759 if (pmd_present(*pmd) && !pmd_huge(*pmd))
760 return 0;
761
762 set_pte((pte_t *)pmd, pfn_pte(
763 (u64)addr >> PAGE_SHIFT,
764 __pgprot(protval_4k_2_large(pgprot_val(prot)) | _PAGE_PSE)));
765
766 return 1;
767}
768
769/**
770 * pud_clear_huge - clear kernel PUD mapping when it is set
771 *
772 * Returns 1 on success and 0 on failure (no PUD map is found).
773 */
774int pud_clear_huge(pud_t *pud)
775{
776 if (pud_large(*pud)) {
777 pud_clear(pud);
778 return 1;
779 }
780
781 return 0;
782}
783
784/**
785 * pmd_clear_huge - clear kernel PMD mapping when it is set
786 *
787 * Returns 1 on success and 0 on failure (no PMD map is found).
788 */
789int pmd_clear_huge(pmd_t *pmd)
790{
791 if (pmd_large(*pmd)) {
792 pmd_clear(pmd);
793 return 1;
794 }
795
796 return 0;
797}
798
799#ifdef CONFIG_X86_64
800/**
801 * pud_free_pmd_page - Clear pud entry and free pmd page.
802 * @pud: Pointer to a PUD.
803 * @addr: Virtual address associated with pud.
804 *
805 * Context: The pud range has been unmapped and TLB purged.
806 * Return: 1 if clearing the entry succeeded. 0 otherwise.
807 *
808 * NOTE: Callers must allow a single page allocation.
809 */
810int pud_free_pmd_page(pud_t *pud, unsigned long addr)
811{
812 pmd_t *pmd, *pmd_sv;
813 pte_t *pte;
814 int i;
815
816 pmd = pud_pgtable(*pud);
817 pmd_sv = (pmd_t *)__get_free_page(GFP_KERNEL);
818 if (!pmd_sv)
819 return 0;
820
821 for (i = 0; i < PTRS_PER_PMD; i++) {
822 pmd_sv[i] = pmd[i];
823 if (!pmd_none(pmd[i]))
824 pmd_clear(&pmd[i]);
825 }
826
827 pud_clear(pud);
828
829 /* INVLPG to clear all paging-structure caches */
830 flush_tlb_kernel_range(addr, addr + PAGE_SIZE-1);
831
832 for (i = 0; i < PTRS_PER_PMD; i++) {
833 if (!pmd_none(pmd_sv[i])) {
834 pte = (pte_t *)pmd_page_vaddr(pmd_sv[i]);
835 free_page((unsigned long)pte);
836 }
837 }
838
839 free_page((unsigned long)pmd_sv);
840
841 pgtable_pmd_page_dtor(virt_to_page(pmd));
842 free_page((unsigned long)pmd);
843
844 return 1;
845}
846
847/**
848 * pmd_free_pte_page - Clear pmd entry and free pte page.
849 * @pmd: Pointer to a PMD.
850 * @addr: Virtual address associated with pmd.
851 *
852 * Context: The pmd range has been unmapped and TLB purged.
853 * Return: 1 if clearing the entry succeeded. 0 otherwise.
854 */
855int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
856{
857 pte_t *pte;
858
859 pte = (pte_t *)pmd_page_vaddr(*pmd);
860 pmd_clear(pmd);
861
862 /* INVLPG to clear all paging-structure caches */
863 flush_tlb_kernel_range(addr, addr + PAGE_SIZE-1);
864
865 free_page((unsigned long)pte);
866
867 return 1;
868}
869
870#else /* !CONFIG_X86_64 */
871
872/*
873 * Disable free page handling on x86-PAE. This assures that ioremap()
874 * does not update sync'd pmd entries. See vmalloc_sync_one().
875 */
876int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
877{
878 return pmd_none(*pmd);
879}
880
881#endif /* CONFIG_X86_64 */
882#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/mm.h>
3#include <linux/gfp.h>
4#include <linux/hugetlb.h>
5#include <asm/pgalloc.h>
6#include <asm/pgtable.h>
7#include <asm/tlb.h>
8#include <asm/fixmap.h>
9#include <asm/mtrr.h>
10
11#define PGALLOC_GFP (GFP_KERNEL_ACCOUNT | __GFP_ZERO)
12
13#ifdef CONFIG_HIGHPTE
14#define PGALLOC_USER_GFP __GFP_HIGHMEM
15#else
16#define PGALLOC_USER_GFP 0
17#endif
18
19gfp_t __userpte_alloc_gfp = PGALLOC_GFP | PGALLOC_USER_GFP;
20
21pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
22{
23 return (pte_t *)__get_free_page(PGALLOC_GFP & ~__GFP_ACCOUNT);
24}
25
26pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
27{
28 struct page *pte;
29
30 pte = alloc_pages(__userpte_alloc_gfp, 0);
31 if (!pte)
32 return NULL;
33 if (!pgtable_page_ctor(pte)) {
34 __free_page(pte);
35 return NULL;
36 }
37 return pte;
38}
39
40static int __init setup_userpte(char *arg)
41{
42 if (!arg)
43 return -EINVAL;
44
45 /*
46 * "userpte=nohigh" disables allocation of user pagetables in
47 * high memory.
48 */
49 if (strcmp(arg, "nohigh") == 0)
50 __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
51 else
52 return -EINVAL;
53 return 0;
54}
55early_param("userpte", setup_userpte);
56
57void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
58{
59 pgtable_page_dtor(pte);
60 paravirt_release_pte(page_to_pfn(pte));
61 tlb_remove_table(tlb, pte);
62}
63
64#if CONFIG_PGTABLE_LEVELS > 2
65void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
66{
67 struct page *page = virt_to_page(pmd);
68 paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
69 /*
70 * NOTE! For PAE, any changes to the top page-directory-pointer-table
71 * entries need a full cr3 reload to flush.
72 */
73#ifdef CONFIG_X86_PAE
74 tlb->need_flush_all = 1;
75#endif
76 pgtable_pmd_page_dtor(page);
77 tlb_remove_table(tlb, page);
78}
79
80#if CONFIG_PGTABLE_LEVELS > 3
81void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
82{
83 paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
84 tlb_remove_table(tlb, virt_to_page(pud));
85}
86
87#if CONFIG_PGTABLE_LEVELS > 4
88void ___p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d)
89{
90 paravirt_release_p4d(__pa(p4d) >> PAGE_SHIFT);
91 tlb_remove_table(tlb, virt_to_page(p4d));
92}
93#endif /* CONFIG_PGTABLE_LEVELS > 4 */
94#endif /* CONFIG_PGTABLE_LEVELS > 3 */
95#endif /* CONFIG_PGTABLE_LEVELS > 2 */
96
97static inline void pgd_list_add(pgd_t *pgd)
98{
99 struct page *page = virt_to_page(pgd);
100
101 list_add(&page->lru, &pgd_list);
102}
103
104static inline void pgd_list_del(pgd_t *pgd)
105{
106 struct page *page = virt_to_page(pgd);
107
108 list_del(&page->lru);
109}
110
111#define UNSHARED_PTRS_PER_PGD \
112 (SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
113
114
115static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
116{
117 BUILD_BUG_ON(sizeof(virt_to_page(pgd)->index) < sizeof(mm));
118 virt_to_page(pgd)->index = (pgoff_t)mm;
119}
120
121struct mm_struct *pgd_page_get_mm(struct page *page)
122{
123 return (struct mm_struct *)page->index;
124}
125
126static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
127{
128 /* If the pgd points to a shared pagetable level (either the
129 ptes in non-PAE, or shared PMD in PAE), then just copy the
130 references from swapper_pg_dir. */
131 if (CONFIG_PGTABLE_LEVELS == 2 ||
132 (CONFIG_PGTABLE_LEVELS == 3 && SHARED_KERNEL_PMD) ||
133 CONFIG_PGTABLE_LEVELS >= 4) {
134 clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY,
135 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
136 KERNEL_PGD_PTRS);
137 }
138
139 /* list required to sync kernel mapping updates */
140 if (!SHARED_KERNEL_PMD) {
141 pgd_set_mm(pgd, mm);
142 pgd_list_add(pgd);
143 }
144}
145
146static void pgd_dtor(pgd_t *pgd)
147{
148 if (SHARED_KERNEL_PMD)
149 return;
150
151 spin_lock(&pgd_lock);
152 pgd_list_del(pgd);
153 spin_unlock(&pgd_lock);
154}
155
156/*
157 * List of all pgd's needed for non-PAE so it can invalidate entries
158 * in both cached and uncached pgd's; not needed for PAE since the
159 * kernel pmd is shared. If PAE were not to share the pmd a similar
160 * tactic would be needed. This is essentially codepath-based locking
161 * against pageattr.c; it is the unique case in which a valid change
162 * of kernel pagetables can't be lazily synchronized by vmalloc faults.
163 * vmalloc faults work because attached pagetables are never freed.
164 * -- nyc
165 */
166
167#ifdef CONFIG_X86_PAE
168/*
169 * In PAE mode, we need to do a cr3 reload (=tlb flush) when
170 * updating the top-level pagetable entries to guarantee the
171 * processor notices the update. Since this is expensive, and
172 * all 4 top-level entries are used almost immediately in a
173 * new process's life, we just pre-populate them here.
174 *
175 * Also, if we're in a paravirt environment where the kernel pmd is
176 * not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate
177 * and initialize the kernel pmds here.
178 */
179#define PREALLOCATED_PMDS UNSHARED_PTRS_PER_PGD
180
181void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
182{
183 paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT);
184
185 /* Note: almost everything apart from _PAGE_PRESENT is
186 reserved at the pmd (PDPT) level. */
187 set_pud(pudp, __pud(__pa(pmd) | _PAGE_PRESENT));
188
189 /*
190 * According to Intel App note "TLBs, Paging-Structure Caches,
191 * and Their Invalidation", April 2007, document 317080-001,
192 * section 8.1: in PAE mode we explicitly have to flush the
193 * TLB via cr3 if the top-level pgd is changed...
194 */
195 flush_tlb_mm(mm);
196}
197#else /* !CONFIG_X86_PAE */
198
199/* No need to prepopulate any pagetable entries in non-PAE modes. */
200#define PREALLOCATED_PMDS 0
201
202#endif /* CONFIG_X86_PAE */
203
204static void free_pmds(struct mm_struct *mm, pmd_t *pmds[])
205{
206 int i;
207
208 for(i = 0; i < PREALLOCATED_PMDS; i++)
209 if (pmds[i]) {
210 pgtable_pmd_page_dtor(virt_to_page(pmds[i]));
211 free_page((unsigned long)pmds[i]);
212 mm_dec_nr_pmds(mm);
213 }
214}
215
216static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[])
217{
218 int i;
219 bool failed = false;
220 gfp_t gfp = PGALLOC_GFP;
221
222 if (mm == &init_mm)
223 gfp &= ~__GFP_ACCOUNT;
224
225 for(i = 0; i < PREALLOCATED_PMDS; i++) {
226 pmd_t *pmd = (pmd_t *)__get_free_page(gfp);
227 if (!pmd)
228 failed = true;
229 if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
230 free_page((unsigned long)pmd);
231 pmd = NULL;
232 failed = true;
233 }
234 if (pmd)
235 mm_inc_nr_pmds(mm);
236 pmds[i] = pmd;
237 }
238
239 if (failed) {
240 free_pmds(mm, pmds);
241 return -ENOMEM;
242 }
243
244 return 0;
245}
246
247/*
248 * Mop up any pmd pages which may still be attached to the pgd.
249 * Normally they will be freed by munmap/exit_mmap, but any pmd we
250 * preallocate which never got a corresponding vma will need to be
251 * freed manually.
252 */
253static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
254{
255 int i;
256
257 for(i = 0; i < PREALLOCATED_PMDS; i++) {
258 pgd_t pgd = pgdp[i];
259
260 if (pgd_val(pgd) != 0) {
261 pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
262
263 pgdp[i] = native_make_pgd(0);
264
265 paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT);
266 pmd_free(mm, pmd);
267 mm_dec_nr_pmds(mm);
268 }
269 }
270}
271
272static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
273{
274 p4d_t *p4d;
275 pud_t *pud;
276 int i;
277
278 if (PREALLOCATED_PMDS == 0) /* Work around gcc-3.4.x bug */
279 return;
280
281 p4d = p4d_offset(pgd, 0);
282 pud = pud_offset(p4d, 0);
283
284 for (i = 0; i < PREALLOCATED_PMDS; i++, pud++) {
285 pmd_t *pmd = pmds[i];
286
287 if (i >= KERNEL_PGD_BOUNDARY)
288 memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]),
289 sizeof(pmd_t) * PTRS_PER_PMD);
290
291 pud_populate(mm, pud, pmd);
292 }
293}
294
295/*
296 * Xen paravirt assumes pgd table should be in one page. 64 bit kernel also
297 * assumes that pgd should be in one page.
298 *
299 * But kernel with PAE paging that is not running as a Xen domain
300 * only needs to allocate 32 bytes for pgd instead of one page.
301 */
302#ifdef CONFIG_X86_PAE
303
304#include <linux/slab.h>
305
306#define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t))
307#define PGD_ALIGN 32
308
309static struct kmem_cache *pgd_cache;
310
311static int __init pgd_cache_init(void)
312{
313 /*
314 * When PAE kernel is running as a Xen domain, it does not use
315 * shared kernel pmd. And this requires a whole page for pgd.
316 */
317 if (!SHARED_KERNEL_PMD)
318 return 0;
319
320 /*
321 * when PAE kernel is not running as a Xen domain, it uses
322 * shared kernel pmd. Shared kernel pmd does not require a whole
323 * page for pgd. We are able to just allocate a 32-byte for pgd.
324 * During boot time, we create a 32-byte slab for pgd table allocation.
325 */
326 pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_ALIGN,
327 SLAB_PANIC, NULL);
328 if (!pgd_cache)
329 return -ENOMEM;
330
331 return 0;
332}
333core_initcall(pgd_cache_init);
334
335static inline pgd_t *_pgd_alloc(void)
336{
337 /*
338 * If no SHARED_KERNEL_PMD, PAE kernel is running as a Xen domain.
339 * We allocate one page for pgd.
340 */
341 if (!SHARED_KERNEL_PMD)
342 return (pgd_t *)__get_free_page(PGALLOC_GFP);
343
344 /*
345 * Now PAE kernel is not running as a Xen domain. We can allocate
346 * a 32-byte slab for pgd to save memory space.
347 */
348 return kmem_cache_alloc(pgd_cache, PGALLOC_GFP);
349}
350
351static inline void _pgd_free(pgd_t *pgd)
352{
353 if (!SHARED_KERNEL_PMD)
354 free_page((unsigned long)pgd);
355 else
356 kmem_cache_free(pgd_cache, pgd);
357}
358#else
359
360static inline pgd_t *_pgd_alloc(void)
361{
362 return (pgd_t *)__get_free_pages(PGALLOC_GFP, PGD_ALLOCATION_ORDER);
363}
364
365static inline void _pgd_free(pgd_t *pgd)
366{
367 free_pages((unsigned long)pgd, PGD_ALLOCATION_ORDER);
368}
369#endif /* CONFIG_X86_PAE */
370
371pgd_t *pgd_alloc(struct mm_struct *mm)
372{
373 pgd_t *pgd;
374 pmd_t *pmds[PREALLOCATED_PMDS];
375
376 pgd = _pgd_alloc();
377
378 if (pgd == NULL)
379 goto out;
380
381 mm->pgd = pgd;
382
383 if (preallocate_pmds(mm, pmds) != 0)
384 goto out_free_pgd;
385
386 if (paravirt_pgd_alloc(mm) != 0)
387 goto out_free_pmds;
388
389 /*
390 * Make sure that pre-populating the pmds is atomic with
391 * respect to anything walking the pgd_list, so that they
392 * never see a partially populated pgd.
393 */
394 spin_lock(&pgd_lock);
395
396 pgd_ctor(mm, pgd);
397 pgd_prepopulate_pmd(mm, pgd, pmds);
398
399 spin_unlock(&pgd_lock);
400
401 return pgd;
402
403out_free_pmds:
404 free_pmds(mm, pmds);
405out_free_pgd:
406 _pgd_free(pgd);
407out:
408 return NULL;
409}
410
411void pgd_free(struct mm_struct *mm, pgd_t *pgd)
412{
413 pgd_mop_up_pmds(mm, pgd);
414 pgd_dtor(pgd);
415 paravirt_pgd_free(mm, pgd);
416 _pgd_free(pgd);
417}
418
419/*
420 * Used to set accessed or dirty bits in the page table entries
421 * on other architectures. On x86, the accessed and dirty bits
422 * are tracked by hardware. However, do_wp_page calls this function
423 * to also make the pte writeable at the same time the dirty bit is
424 * set. In that case we do actually need to write the PTE.
425 */
426int ptep_set_access_flags(struct vm_area_struct *vma,
427 unsigned long address, pte_t *ptep,
428 pte_t entry, int dirty)
429{
430 int changed = !pte_same(*ptep, entry);
431
432 if (changed && dirty)
433 *ptep = entry;
434
435 return changed;
436}
437
438#ifdef CONFIG_TRANSPARENT_HUGEPAGE
439int pmdp_set_access_flags(struct vm_area_struct *vma,
440 unsigned long address, pmd_t *pmdp,
441 pmd_t entry, int dirty)
442{
443 int changed = !pmd_same(*pmdp, entry);
444
445 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
446
447 if (changed && dirty) {
448 *pmdp = entry;
449 /*
450 * We had a write-protection fault here and changed the pmd
451 * to to more permissive. No need to flush the TLB for that,
452 * #PF is architecturally guaranteed to do that and in the
453 * worst-case we'll generate a spurious fault.
454 */
455 }
456
457 return changed;
458}
459
460int pudp_set_access_flags(struct vm_area_struct *vma, unsigned long address,
461 pud_t *pudp, pud_t entry, int dirty)
462{
463 int changed = !pud_same(*pudp, entry);
464
465 VM_BUG_ON(address & ~HPAGE_PUD_MASK);
466
467 if (changed && dirty) {
468 *pudp = entry;
469 /*
470 * We had a write-protection fault here and changed the pud
471 * to to more permissive. No need to flush the TLB for that,
472 * #PF is architecturally guaranteed to do that and in the
473 * worst-case we'll generate a spurious fault.
474 */
475 }
476
477 return changed;
478}
479#endif
480
481int ptep_test_and_clear_young(struct vm_area_struct *vma,
482 unsigned long addr, pte_t *ptep)
483{
484 int ret = 0;
485
486 if (pte_young(*ptep))
487 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
488 (unsigned long *) &ptep->pte);
489
490 return ret;
491}
492
493#ifdef CONFIG_TRANSPARENT_HUGEPAGE
494int pmdp_test_and_clear_young(struct vm_area_struct *vma,
495 unsigned long addr, pmd_t *pmdp)
496{
497 int ret = 0;
498
499 if (pmd_young(*pmdp))
500 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
501 (unsigned long *)pmdp);
502
503 return ret;
504}
505int pudp_test_and_clear_young(struct vm_area_struct *vma,
506 unsigned long addr, pud_t *pudp)
507{
508 int ret = 0;
509
510 if (pud_young(*pudp))
511 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
512 (unsigned long *)pudp);
513
514 return ret;
515}
516#endif
517
518int ptep_clear_flush_young(struct vm_area_struct *vma,
519 unsigned long address, pte_t *ptep)
520{
521 /*
522 * On x86 CPUs, clearing the accessed bit without a TLB flush
523 * doesn't cause data corruption. [ It could cause incorrect
524 * page aging and the (mistaken) reclaim of hot pages, but the
525 * chance of that should be relatively low. ]
526 *
527 * So as a performance optimization don't flush the TLB when
528 * clearing the accessed bit, it will eventually be flushed by
529 * a context switch or a VM operation anyway. [ In the rare
530 * event of it not getting flushed for a long time the delay
531 * shouldn't really matter because there's no real memory
532 * pressure for swapout to react to. ]
533 */
534 return ptep_test_and_clear_young(vma, address, ptep);
535}
536
537#ifdef CONFIG_TRANSPARENT_HUGEPAGE
538int pmdp_clear_flush_young(struct vm_area_struct *vma,
539 unsigned long address, pmd_t *pmdp)
540{
541 int young;
542
543 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
544
545 young = pmdp_test_and_clear_young(vma, address, pmdp);
546 if (young)
547 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
548
549 return young;
550}
551#endif
552
553/**
554 * reserve_top_address - reserves a hole in the top of kernel address space
555 * @reserve - size of hole to reserve
556 *
557 * Can be used to relocate the fixmap area and poke a hole in the top
558 * of kernel address space to make room for a hypervisor.
559 */
560void __init reserve_top_address(unsigned long reserve)
561{
562#ifdef CONFIG_X86_32
563 BUG_ON(fixmaps_set > 0);
564 __FIXADDR_TOP = round_down(-reserve, 1 << PMD_SHIFT) - PAGE_SIZE;
565 printk(KERN_INFO "Reserving virtual address space above 0x%08lx (rounded to 0x%08lx)\n",
566 -reserve, __FIXADDR_TOP + PAGE_SIZE);
567#endif
568}
569
570int fixmaps_set;
571
572void __native_set_fixmap(enum fixed_addresses idx, pte_t pte)
573{
574 unsigned long address = __fix_to_virt(idx);
575
576 if (idx >= __end_of_fixed_addresses) {
577 BUG();
578 return;
579 }
580 set_pte_vaddr(address, pte);
581 fixmaps_set++;
582}
583
584void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys,
585 pgprot_t flags)
586{
587 /* Sanitize 'prot' against any unsupported bits: */
588 pgprot_val(flags) &= __default_kernel_pte_mask;
589
590 __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags));
591}
592
593#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
594#ifdef CONFIG_X86_5LEVEL
595/**
596 * p4d_set_huge - setup kernel P4D mapping
597 *
598 * No 512GB pages yet -- always return 0
599 */
600int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
601{
602 return 0;
603}
604
605/**
606 * p4d_clear_huge - clear kernel P4D mapping when it is set
607 *
608 * No 512GB pages yet -- always return 0
609 */
610int p4d_clear_huge(p4d_t *p4d)
611{
612 return 0;
613}
614#endif
615
616/**
617 * pud_set_huge - setup kernel PUD mapping
618 *
619 * MTRRs can override PAT memory types with 4KiB granularity. Therefore, this
620 * function sets up a huge page only if any of the following conditions are met:
621 *
622 * - MTRRs are disabled, or
623 *
624 * - MTRRs are enabled and the range is completely covered by a single MTRR, or
625 *
626 * - MTRRs are enabled and the corresponding MTRR memory type is WB, which
627 * has no effect on the requested PAT memory type.
628 *
629 * Callers should try to decrease page size (1GB -> 2MB -> 4K) if the bigger
630 * page mapping attempt fails.
631 *
632 * Returns 1 on success and 0 on failure.
633 */
634int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
635{
636 u8 mtrr, uniform;
637
638 mtrr = mtrr_type_lookup(addr, addr + PUD_SIZE, &uniform);
639 if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) &&
640 (mtrr != MTRR_TYPE_WRBACK))
641 return 0;
642
643 /* Bail out if we are we on a populated non-leaf entry: */
644 if (pud_present(*pud) && !pud_huge(*pud))
645 return 0;
646
647 prot = pgprot_4k_2_large(prot);
648
649 set_pte((pte_t *)pud, pfn_pte(
650 (u64)addr >> PAGE_SHIFT,
651 __pgprot(pgprot_val(prot) | _PAGE_PSE)));
652
653 return 1;
654}
655
656/**
657 * pmd_set_huge - setup kernel PMD mapping
658 *
659 * See text over pud_set_huge() above.
660 *
661 * Returns 1 on success and 0 on failure.
662 */
663int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
664{
665 u8 mtrr, uniform;
666
667 mtrr = mtrr_type_lookup(addr, addr + PMD_SIZE, &uniform);
668 if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) &&
669 (mtrr != MTRR_TYPE_WRBACK)) {
670 pr_warn_once("%s: Cannot satisfy [mem %#010llx-%#010llx] with a huge-page mapping due to MTRR override.\n",
671 __func__, addr, addr + PMD_SIZE);
672 return 0;
673 }
674
675 /* Bail out if we are we on a populated non-leaf entry: */
676 if (pmd_present(*pmd) && !pmd_huge(*pmd))
677 return 0;
678
679 prot = pgprot_4k_2_large(prot);
680
681 set_pte((pte_t *)pmd, pfn_pte(
682 (u64)addr >> PAGE_SHIFT,
683 __pgprot(pgprot_val(prot) | _PAGE_PSE)));
684
685 return 1;
686}
687
688/**
689 * pud_clear_huge - clear kernel PUD mapping when it is set
690 *
691 * Returns 1 on success and 0 on failure (no PUD map is found).
692 */
693int pud_clear_huge(pud_t *pud)
694{
695 if (pud_large(*pud)) {
696 pud_clear(pud);
697 return 1;
698 }
699
700 return 0;
701}
702
703/**
704 * pmd_clear_huge - clear kernel PMD mapping when it is set
705 *
706 * Returns 1 on success and 0 on failure (no PMD map is found).
707 */
708int pmd_clear_huge(pmd_t *pmd)
709{
710 if (pmd_large(*pmd)) {
711 pmd_clear(pmd);
712 return 1;
713 }
714
715 return 0;
716}
717
718/**
719 * pud_free_pmd_page - Clear pud entry and free pmd page.
720 * @pud: Pointer to a PUD.
721 *
722 * Context: The pud range has been unmaped and TLB purged.
723 * Return: 1 if clearing the entry succeeded. 0 otherwise.
724 */
725int pud_free_pmd_page(pud_t *pud)
726{
727 pmd_t *pmd;
728 int i;
729
730 if (pud_none(*pud))
731 return 1;
732
733 pmd = (pmd_t *)pud_page_vaddr(*pud);
734
735 for (i = 0; i < PTRS_PER_PMD; i++)
736 if (!pmd_free_pte_page(&pmd[i]))
737 return 0;
738
739 pud_clear(pud);
740 free_page((unsigned long)pmd);
741
742 return 1;
743}
744
745/**
746 * pmd_free_pte_page - Clear pmd entry and free pte page.
747 * @pmd: Pointer to a PMD.
748 *
749 * Context: The pmd range has been unmaped and TLB purged.
750 * Return: 1 if clearing the entry succeeded. 0 otherwise.
751 */
752int pmd_free_pte_page(pmd_t *pmd)
753{
754 pte_t *pte;
755
756 if (pmd_none(*pmd))
757 return 1;
758
759 pte = (pte_t *)pmd_page_vaddr(*pmd);
760 pmd_clear(pmd);
761 free_page((unsigned long)pte);
762
763 return 1;
764}
765#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */