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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#ifdef CONFIG_DYNAMIC_PHYSICAL_MASK
12phys_addr_t physical_mask __ro_after_init = (1ULL << __PHYSICAL_MASK_SHIFT) - 1;
13EXPORT_SYMBOL(physical_mask);
14#endif
15
16#ifdef CONFIG_HIGHPTE
17#define PGTABLE_HIGHMEM __GFP_HIGHMEM
18#else
19#define PGTABLE_HIGHMEM 0
20#endif
21
22gfp_t __userpte_alloc_gfp = GFP_PGTABLE_USER | PGTABLE_HIGHMEM;
23
24pgtable_t pte_alloc_one(struct mm_struct *mm)
25{
26 return __pte_alloc_one(mm, __userpte_alloc_gfp);
27}
28
29static int __init setup_userpte(char *arg)
30{
31 if (!arg)
32 return -EINVAL;
33
34 /*
35 * "userpte=nohigh" disables allocation of user pagetables in
36 * high memory.
37 */
38 if (strcmp(arg, "nohigh") == 0)
39 __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
40 else
41 return -EINVAL;
42 return 0;
43}
44early_param("userpte", setup_userpte);
45
46void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
47{
48 pgtable_pte_page_dtor(pte);
49 paravirt_release_pte(page_to_pfn(pte));
50 paravirt_tlb_remove_table(tlb, pte);
51}
52
53#if CONFIG_PGTABLE_LEVELS > 2
54void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
55{
56 struct page *page = virt_to_page(pmd);
57 paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
58 /*
59 * NOTE! For PAE, any changes to the top page-directory-pointer-table
60 * entries need a full cr3 reload to flush.
61 */
62#ifdef CONFIG_X86_PAE
63 tlb->need_flush_all = 1;
64#endif
65 pgtable_pmd_page_dtor(page);
66 paravirt_tlb_remove_table(tlb, page);
67}
68
69#if CONFIG_PGTABLE_LEVELS > 3
70void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
71{
72 paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
73 paravirt_tlb_remove_table(tlb, virt_to_page(pud));
74}
75
76#if CONFIG_PGTABLE_LEVELS > 4
77void ___p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d)
78{
79 paravirt_release_p4d(__pa(p4d) >> PAGE_SHIFT);
80 paravirt_tlb_remove_table(tlb, virt_to_page(p4d));
81}
82#endif /* CONFIG_PGTABLE_LEVELS > 4 */
83#endif /* CONFIG_PGTABLE_LEVELS > 3 */
84#endif /* CONFIG_PGTABLE_LEVELS > 2 */
85
86static inline void pgd_list_add(pgd_t *pgd)
87{
88 struct page *page = virt_to_page(pgd);
89
90 list_add(&page->lru, &pgd_list);
91}
92
93static inline void pgd_list_del(pgd_t *pgd)
94{
95 struct page *page = virt_to_page(pgd);
96
97 list_del(&page->lru);
98}
99
100#define UNSHARED_PTRS_PER_PGD \
101 (SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
102#define MAX_UNSHARED_PTRS_PER_PGD \
103 max_t(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD)
104
105
106static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
107{
108 virt_to_page(pgd)->pt_mm = mm;
109}
110
111struct mm_struct *pgd_page_get_mm(struct page *page)
112{
113 return page->pt_mm;
114}
115
116static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
117{
118 /* If the pgd points to a shared pagetable level (either the
119 ptes in non-PAE, or shared PMD in PAE), then just copy the
120 references from swapper_pg_dir. */
121 if (CONFIG_PGTABLE_LEVELS == 2 ||
122 (CONFIG_PGTABLE_LEVELS == 3 && SHARED_KERNEL_PMD) ||
123 CONFIG_PGTABLE_LEVELS >= 4) {
124 clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY,
125 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
126 KERNEL_PGD_PTRS);
127 }
128
129 /* list required to sync kernel mapping updates */
130 if (!SHARED_KERNEL_PMD) {
131 pgd_set_mm(pgd, mm);
132 pgd_list_add(pgd);
133 }
134}
135
136static void pgd_dtor(pgd_t *pgd)
137{
138 if (SHARED_KERNEL_PMD)
139 return;
140
141 spin_lock(&pgd_lock);
142 pgd_list_del(pgd);
143 spin_unlock(&pgd_lock);
144}
145
146/*
147 * List of all pgd's needed for non-PAE so it can invalidate entries
148 * in both cached and uncached pgd's; not needed for PAE since the
149 * kernel pmd is shared. If PAE were not to share the pmd a similar
150 * tactic would be needed. This is essentially codepath-based locking
151 * against pageattr.c; it is the unique case in which a valid change
152 * of kernel pagetables can't be lazily synchronized by vmalloc faults.
153 * vmalloc faults work because attached pagetables are never freed.
154 * -- nyc
155 */
156
157#ifdef CONFIG_X86_PAE
158/*
159 * In PAE mode, we need to do a cr3 reload (=tlb flush) when
160 * updating the top-level pagetable entries to guarantee the
161 * processor notices the update. Since this is expensive, and
162 * all 4 top-level entries are used almost immediately in a
163 * new process's life, we just pre-populate them here.
164 *
165 * Also, if we're in a paravirt environment where the kernel pmd is
166 * not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate
167 * and initialize the kernel pmds here.
168 */
169#define PREALLOCATED_PMDS UNSHARED_PTRS_PER_PGD
170#define MAX_PREALLOCATED_PMDS MAX_UNSHARED_PTRS_PER_PGD
171
172/*
173 * We allocate separate PMDs for the kernel part of the user page-table
174 * when PTI is enabled. We need them to map the per-process LDT into the
175 * user-space page-table.
176 */
177#define PREALLOCATED_USER_PMDS (boot_cpu_has(X86_FEATURE_PTI) ? \
178 KERNEL_PGD_PTRS : 0)
179#define MAX_PREALLOCATED_USER_PMDS KERNEL_PGD_PTRS
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#define MAX_PREALLOCATED_PMDS 0
202#define PREALLOCATED_USER_PMDS 0
203#define MAX_PREALLOCATED_USER_PMDS 0
204#endif /* CONFIG_X86_PAE */
205
206static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
207{
208 int i;
209
210 for (i = 0; i < count; i++)
211 if (pmds[i]) {
212 pgtable_pmd_page_dtor(virt_to_page(pmds[i]));
213 free_page((unsigned long)pmds[i]);
214 mm_dec_nr_pmds(mm);
215 }
216}
217
218static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
219{
220 int i;
221 bool failed = false;
222 gfp_t gfp = GFP_PGTABLE_USER;
223
224 if (mm == &init_mm)
225 gfp &= ~__GFP_ACCOUNT;
226
227 for (i = 0; i < count; i++) {
228 pmd_t *pmd = (pmd_t *)__get_free_page(gfp);
229 if (!pmd)
230 failed = true;
231 if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
232 free_page((unsigned long)pmd);
233 pmd = NULL;
234 failed = true;
235 }
236 if (pmd)
237 mm_inc_nr_pmds(mm);
238 pmds[i] = pmd;
239 }
240
241 if (failed) {
242 free_pmds(mm, pmds, count);
243 return -ENOMEM;
244 }
245
246 return 0;
247}
248
249/*
250 * Mop up any pmd pages which may still be attached to the pgd.
251 * Normally they will be freed by munmap/exit_mmap, but any pmd we
252 * preallocate which never got a corresponding vma will need to be
253 * freed manually.
254 */
255static void mop_up_one_pmd(struct mm_struct *mm, pgd_t *pgdp)
256{
257 pgd_t pgd = *pgdp;
258
259 if (pgd_val(pgd) != 0) {
260 pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
261
262 pgd_clear(pgdp);
263
264 paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT);
265 pmd_free(mm, pmd);
266 mm_dec_nr_pmds(mm);
267 }
268}
269
270static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
271{
272 int i;
273
274 for (i = 0; i < PREALLOCATED_PMDS; i++)
275 mop_up_one_pmd(mm, &pgdp[i]);
276
277#ifdef CONFIG_PAGE_TABLE_ISOLATION
278
279 if (!boot_cpu_has(X86_FEATURE_PTI))
280 return;
281
282 pgdp = kernel_to_user_pgdp(pgdp);
283
284 for (i = 0; i < PREALLOCATED_USER_PMDS; i++)
285 mop_up_one_pmd(mm, &pgdp[i + KERNEL_PGD_BOUNDARY]);
286#endif
287}
288
289static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
290{
291 p4d_t *p4d;
292 pud_t *pud;
293 int i;
294
295 if (PREALLOCATED_PMDS == 0) /* Work around gcc-3.4.x bug */
296 return;
297
298 p4d = p4d_offset(pgd, 0);
299 pud = pud_offset(p4d, 0);
300
301 for (i = 0; i < PREALLOCATED_PMDS; i++, pud++) {
302 pmd_t *pmd = pmds[i];
303
304 if (i >= KERNEL_PGD_BOUNDARY)
305 memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]),
306 sizeof(pmd_t) * PTRS_PER_PMD);
307
308 pud_populate(mm, pud, pmd);
309 }
310}
311
312#ifdef CONFIG_PAGE_TABLE_ISOLATION
313static void pgd_prepopulate_user_pmd(struct mm_struct *mm,
314 pgd_t *k_pgd, pmd_t *pmds[])
315{
316 pgd_t *s_pgd = kernel_to_user_pgdp(swapper_pg_dir);
317 pgd_t *u_pgd = kernel_to_user_pgdp(k_pgd);
318 p4d_t *u_p4d;
319 pud_t *u_pud;
320 int i;
321
322 u_p4d = p4d_offset(u_pgd, 0);
323 u_pud = pud_offset(u_p4d, 0);
324
325 s_pgd += KERNEL_PGD_BOUNDARY;
326 u_pud += KERNEL_PGD_BOUNDARY;
327
328 for (i = 0; i < PREALLOCATED_USER_PMDS; i++, u_pud++, s_pgd++) {
329 pmd_t *pmd = pmds[i];
330
331 memcpy(pmd, (pmd_t *)pgd_page_vaddr(*s_pgd),
332 sizeof(pmd_t) * PTRS_PER_PMD);
333
334 pud_populate(mm, u_pud, pmd);
335 }
336
337}
338#else
339static void pgd_prepopulate_user_pmd(struct mm_struct *mm,
340 pgd_t *k_pgd, pmd_t *pmds[])
341{
342}
343#endif
344/*
345 * Xen paravirt assumes pgd table should be in one page. 64 bit kernel also
346 * assumes that pgd should be in one page.
347 *
348 * But kernel with PAE paging that is not running as a Xen domain
349 * only needs to allocate 32 bytes for pgd instead of one page.
350 */
351#ifdef CONFIG_X86_PAE
352
353#include <linux/slab.h>
354
355#define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t))
356#define PGD_ALIGN 32
357
358static struct kmem_cache *pgd_cache;
359
360void __init pgtable_cache_init(void)
361{
362 /*
363 * When PAE kernel is running as a Xen domain, it does not use
364 * shared kernel pmd. And this requires a whole page for pgd.
365 */
366 if (!SHARED_KERNEL_PMD)
367 return;
368
369 /*
370 * when PAE kernel is not running as a Xen domain, it uses
371 * shared kernel pmd. Shared kernel pmd does not require a whole
372 * page for pgd. We are able to just allocate a 32-byte for pgd.
373 * During boot time, we create a 32-byte slab for pgd table allocation.
374 */
375 pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_ALIGN,
376 SLAB_PANIC, NULL);
377}
378
379static inline pgd_t *_pgd_alloc(void)
380{
381 /*
382 * If no SHARED_KERNEL_PMD, PAE kernel is running as a Xen domain.
383 * We allocate one page for pgd.
384 */
385 if (!SHARED_KERNEL_PMD)
386 return (pgd_t *)__get_free_pages(GFP_PGTABLE_USER,
387 PGD_ALLOCATION_ORDER);
388
389 /*
390 * Now PAE kernel is not running as a Xen domain. We can allocate
391 * a 32-byte slab for pgd to save memory space.
392 */
393 return kmem_cache_alloc(pgd_cache, GFP_PGTABLE_USER);
394}
395
396static inline void _pgd_free(pgd_t *pgd)
397{
398 if (!SHARED_KERNEL_PMD)
399 free_pages((unsigned long)pgd, PGD_ALLOCATION_ORDER);
400 else
401 kmem_cache_free(pgd_cache, pgd);
402}
403#else
404
405static inline pgd_t *_pgd_alloc(void)
406{
407 return (pgd_t *)__get_free_pages(GFP_PGTABLE_USER,
408 PGD_ALLOCATION_ORDER);
409}
410
411static inline void _pgd_free(pgd_t *pgd)
412{
413 free_pages((unsigned long)pgd, PGD_ALLOCATION_ORDER);
414}
415#endif /* CONFIG_X86_PAE */
416
417pgd_t *pgd_alloc(struct mm_struct *mm)
418{
419 pgd_t *pgd;
420 pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS];
421 pmd_t *pmds[MAX_PREALLOCATED_PMDS];
422
423 pgd = _pgd_alloc();
424
425 if (pgd == NULL)
426 goto out;
427
428 mm->pgd = pgd;
429
430 if (preallocate_pmds(mm, pmds, PREALLOCATED_PMDS) != 0)
431 goto out_free_pgd;
432
433 if (preallocate_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS) != 0)
434 goto out_free_pmds;
435
436 if (paravirt_pgd_alloc(mm) != 0)
437 goto out_free_user_pmds;
438
439 /*
440 * Make sure that pre-populating the pmds is atomic with
441 * respect to anything walking the pgd_list, so that they
442 * never see a partially populated pgd.
443 */
444 spin_lock(&pgd_lock);
445
446 pgd_ctor(mm, pgd);
447 pgd_prepopulate_pmd(mm, pgd, pmds);
448 pgd_prepopulate_user_pmd(mm, pgd, u_pmds);
449
450 spin_unlock(&pgd_lock);
451
452 return pgd;
453
454out_free_user_pmds:
455 free_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS);
456out_free_pmds:
457 free_pmds(mm, pmds, PREALLOCATED_PMDS);
458out_free_pgd:
459 _pgd_free(pgd);
460out:
461 return NULL;
462}
463
464void pgd_free(struct mm_struct *mm, pgd_t *pgd)
465{
466 pgd_mop_up_pmds(mm, pgd);
467 pgd_dtor(pgd);
468 paravirt_pgd_free(mm, pgd);
469 _pgd_free(pgd);
470}
471
472/*
473 * Used to set accessed or dirty bits in the page table entries
474 * on other architectures. On x86, the accessed and dirty bits
475 * are tracked by hardware. However, do_wp_page calls this function
476 * to also make the pte writeable at the same time the dirty bit is
477 * set. In that case we do actually need to write the PTE.
478 */
479int ptep_set_access_flags(struct vm_area_struct *vma,
480 unsigned long address, pte_t *ptep,
481 pte_t entry, int dirty)
482{
483 int changed = !pte_same(*ptep, entry);
484
485 if (changed && dirty)
486 set_pte(ptep, entry);
487
488 return changed;
489}
490
491#ifdef CONFIG_TRANSPARENT_HUGEPAGE
492int pmdp_set_access_flags(struct vm_area_struct *vma,
493 unsigned long address, pmd_t *pmdp,
494 pmd_t entry, int dirty)
495{
496 int changed = !pmd_same(*pmdp, entry);
497
498 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
499
500 if (changed && dirty) {
501 set_pmd(pmdp, entry);
502 /*
503 * We had a write-protection fault here and changed the pmd
504 * to to more permissive. No need to flush the TLB for that,
505 * #PF is architecturally guaranteed to do that and in the
506 * worst-case we'll generate a spurious fault.
507 */
508 }
509
510 return changed;
511}
512
513int pudp_set_access_flags(struct vm_area_struct *vma, unsigned long address,
514 pud_t *pudp, pud_t entry, int dirty)
515{
516 int changed = !pud_same(*pudp, entry);
517
518 VM_BUG_ON(address & ~HPAGE_PUD_MASK);
519
520 if (changed && dirty) {
521 set_pud(pudp, entry);
522 /*
523 * We had a write-protection fault here and changed the pud
524 * to to more permissive. No need to flush the TLB for that,
525 * #PF is architecturally guaranteed to do that and in the
526 * worst-case we'll generate a spurious fault.
527 */
528 }
529
530 return changed;
531}
532#endif
533
534int ptep_test_and_clear_young(struct vm_area_struct *vma,
535 unsigned long addr, pte_t *ptep)
536{
537 int ret = 0;
538
539 if (pte_young(*ptep))
540 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
541 (unsigned long *) &ptep->pte);
542
543 return ret;
544}
545
546#ifdef CONFIG_TRANSPARENT_HUGEPAGE
547int pmdp_test_and_clear_young(struct vm_area_struct *vma,
548 unsigned long addr, pmd_t *pmdp)
549{
550 int ret = 0;
551
552 if (pmd_young(*pmdp))
553 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
554 (unsigned long *)pmdp);
555
556 return ret;
557}
558int pudp_test_and_clear_young(struct vm_area_struct *vma,
559 unsigned long addr, pud_t *pudp)
560{
561 int ret = 0;
562
563 if (pud_young(*pudp))
564 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
565 (unsigned long *)pudp);
566
567 return ret;
568}
569#endif
570
571int ptep_clear_flush_young(struct vm_area_struct *vma,
572 unsigned long address, pte_t *ptep)
573{
574 /*
575 * On x86 CPUs, clearing the accessed bit without a TLB flush
576 * doesn't cause data corruption. [ It could cause incorrect
577 * page aging and the (mistaken) reclaim of hot pages, but the
578 * chance of that should be relatively low. ]
579 *
580 * So as a performance optimization don't flush the TLB when
581 * clearing the accessed bit, it will eventually be flushed by
582 * a context switch or a VM operation anyway. [ In the rare
583 * event of it not getting flushed for a long time the delay
584 * shouldn't really matter because there's no real memory
585 * pressure for swapout to react to. ]
586 */
587 return ptep_test_and_clear_young(vma, address, ptep);
588}
589
590#ifdef CONFIG_TRANSPARENT_HUGEPAGE
591int pmdp_clear_flush_young(struct vm_area_struct *vma,
592 unsigned long address, pmd_t *pmdp)
593{
594 int young;
595
596 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
597
598 young = pmdp_test_and_clear_young(vma, address, pmdp);
599 if (young)
600 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
601
602 return young;
603}
604#endif
605
606/**
607 * reserve_top_address - reserves a hole in the top of kernel address space
608 * @reserve - size of hole to reserve
609 *
610 * Can be used to relocate the fixmap area and poke a hole in the top
611 * of kernel address space to make room for a hypervisor.
612 */
613void __init reserve_top_address(unsigned long reserve)
614{
615#ifdef CONFIG_X86_32
616 BUG_ON(fixmaps_set > 0);
617 __FIXADDR_TOP = round_down(-reserve, 1 << PMD_SHIFT) - PAGE_SIZE;
618 printk(KERN_INFO "Reserving virtual address space above 0x%08lx (rounded to 0x%08lx)\n",
619 -reserve, __FIXADDR_TOP + PAGE_SIZE);
620#endif
621}
622
623int fixmaps_set;
624
625void __native_set_fixmap(enum fixed_addresses idx, pte_t pte)
626{
627 unsigned long address = __fix_to_virt(idx);
628
629#ifdef CONFIG_X86_64
630 /*
631 * Ensure that the static initial page tables are covering the
632 * fixmap completely.
633 */
634 BUILD_BUG_ON(__end_of_permanent_fixed_addresses >
635 (FIXMAP_PMD_NUM * PTRS_PER_PTE));
636#endif
637
638 if (idx >= __end_of_fixed_addresses) {
639 BUG();
640 return;
641 }
642 set_pte_vaddr(address, pte);
643 fixmaps_set++;
644}
645
646void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys,
647 pgprot_t flags)
648{
649 /* Sanitize 'prot' against any unsupported bits: */
650 pgprot_val(flags) &= __default_kernel_pte_mask;
651
652 __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags));
653}
654
655#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
656#ifdef CONFIG_X86_5LEVEL
657/**
658 * p4d_set_huge - setup kernel P4D mapping
659 *
660 * No 512GB pages yet -- always return 0
661 */
662int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
663{
664 return 0;
665}
666
667/**
668 * p4d_clear_huge - clear kernel P4D mapping when it is set
669 *
670 * No 512GB pages yet -- always return 0
671 */
672int p4d_clear_huge(p4d_t *p4d)
673{
674 return 0;
675}
676#endif
677
678/**
679 * pud_set_huge - setup kernel PUD mapping
680 *
681 * MTRRs can override PAT memory types with 4KiB granularity. Therefore, this
682 * function sets up a huge page only if any of the following conditions are met:
683 *
684 * - MTRRs are disabled, or
685 *
686 * - MTRRs are enabled and the range is completely covered by a single MTRR, or
687 *
688 * - MTRRs are enabled and the corresponding MTRR memory type is WB, which
689 * has no effect on the requested PAT memory type.
690 *
691 * Callers should try to decrease page size (1GB -> 2MB -> 4K) if the bigger
692 * page mapping attempt fails.
693 *
694 * Returns 1 on success and 0 on failure.
695 */
696int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
697{
698 u8 mtrr, uniform;
699
700 mtrr = mtrr_type_lookup(addr, addr + PUD_SIZE, &uniform);
701 if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) &&
702 (mtrr != MTRR_TYPE_WRBACK))
703 return 0;
704
705 /* Bail out if we are we on a populated non-leaf entry: */
706 if (pud_present(*pud) && !pud_huge(*pud))
707 return 0;
708
709 prot = pgprot_4k_2_large(prot);
710
711 set_pte((pte_t *)pud, pfn_pte(
712 (u64)addr >> PAGE_SHIFT,
713 __pgprot(pgprot_val(prot) | _PAGE_PSE)));
714
715 return 1;
716}
717
718/**
719 * pmd_set_huge - setup kernel PMD mapping
720 *
721 * See text over pud_set_huge() above.
722 *
723 * Returns 1 on success and 0 on failure.
724 */
725int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
726{
727 u8 mtrr, uniform;
728
729 mtrr = mtrr_type_lookup(addr, addr + PMD_SIZE, &uniform);
730 if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) &&
731 (mtrr != MTRR_TYPE_WRBACK)) {
732 pr_warn_once("%s: Cannot satisfy [mem %#010llx-%#010llx] with a huge-page mapping due to MTRR override.\n",
733 __func__, addr, addr + PMD_SIZE);
734 return 0;
735 }
736
737 /* Bail out if we are we on a populated non-leaf entry: */
738 if (pmd_present(*pmd) && !pmd_huge(*pmd))
739 return 0;
740
741 prot = pgprot_4k_2_large(prot);
742
743 set_pte((pte_t *)pmd, pfn_pte(
744 (u64)addr >> PAGE_SHIFT,
745 __pgprot(pgprot_val(prot) | _PAGE_PSE)));
746
747 return 1;
748}
749
750/**
751 * pud_clear_huge - clear kernel PUD mapping when it is set
752 *
753 * Returns 1 on success and 0 on failure (no PUD map is found).
754 */
755int pud_clear_huge(pud_t *pud)
756{
757 if (pud_large(*pud)) {
758 pud_clear(pud);
759 return 1;
760 }
761
762 return 0;
763}
764
765/**
766 * pmd_clear_huge - clear kernel PMD mapping when it is set
767 *
768 * Returns 1 on success and 0 on failure (no PMD map is found).
769 */
770int pmd_clear_huge(pmd_t *pmd)
771{
772 if (pmd_large(*pmd)) {
773 pmd_clear(pmd);
774 return 1;
775 }
776
777 return 0;
778}
779
780/*
781 * Until we support 512GB pages, skip them in the vmap area.
782 */
783int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
784{
785 return 0;
786}
787
788#ifdef CONFIG_X86_64
789/**
790 * pud_free_pmd_page - Clear pud entry and free pmd page.
791 * @pud: Pointer to a PUD.
792 * @addr: Virtual address associated with pud.
793 *
794 * Context: The pud range has been unmapped and TLB purged.
795 * Return: 1 if clearing the entry succeeded. 0 otherwise.
796 *
797 * NOTE: Callers must allow a single page allocation.
798 */
799int pud_free_pmd_page(pud_t *pud, unsigned long addr)
800{
801 pmd_t *pmd, *pmd_sv;
802 pte_t *pte;
803 int i;
804
805 pmd = (pmd_t *)pud_page_vaddr(*pud);
806 pmd_sv = (pmd_t *)__get_free_page(GFP_KERNEL);
807 if (!pmd_sv)
808 return 0;
809
810 for (i = 0; i < PTRS_PER_PMD; i++) {
811 pmd_sv[i] = pmd[i];
812 if (!pmd_none(pmd[i]))
813 pmd_clear(&pmd[i]);
814 }
815
816 pud_clear(pud);
817
818 /* INVLPG to clear all paging-structure caches */
819 flush_tlb_kernel_range(addr, addr + PAGE_SIZE-1);
820
821 for (i = 0; i < PTRS_PER_PMD; i++) {
822 if (!pmd_none(pmd_sv[i])) {
823 pte = (pte_t *)pmd_page_vaddr(pmd_sv[i]);
824 free_page((unsigned long)pte);
825 }
826 }
827
828 free_page((unsigned long)pmd_sv);
829 free_page((unsigned long)pmd);
830
831 return 1;
832}
833
834/**
835 * pmd_free_pte_page - Clear pmd entry and free pte page.
836 * @pmd: Pointer to a PMD.
837 * @addr: Virtual address associated with pmd.
838 *
839 * Context: The pmd range has been unmapped and TLB purged.
840 * Return: 1 if clearing the entry succeeded. 0 otherwise.
841 */
842int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
843{
844 pte_t *pte;
845
846 pte = (pte_t *)pmd_page_vaddr(*pmd);
847 pmd_clear(pmd);
848
849 /* INVLPG to clear all paging-structure caches */
850 flush_tlb_kernel_range(addr, addr + PAGE_SIZE-1);
851
852 free_page((unsigned long)pte);
853
854 return 1;
855}
856
857#else /* !CONFIG_X86_64 */
858
859int pud_free_pmd_page(pud_t *pud, unsigned long addr)
860{
861 return pud_none(*pud);
862}
863
864/*
865 * Disable free page handling on x86-PAE. This assures that ioremap()
866 * does not update sync'd pmd entries. See vmalloc_sync_one().
867 */
868int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
869{
870 return pmd_none(*pmd);
871}
872
873#endif /* CONFIG_X86_64 */
874#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */