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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#include <linux/mm.h>
2#include <linux/gfp.h>
3#include <asm/pgalloc.h>
4#include <asm/pgtable.h>
5#include <asm/tlb.h>
6#include <asm/fixmap.h>
7
8#define PGALLOC_GFP GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO
9
10#ifdef CONFIG_HIGHPTE
11#define PGALLOC_USER_GFP __GFP_HIGHMEM
12#else
13#define PGALLOC_USER_GFP 0
14#endif
15
16gfp_t __userpte_alloc_gfp = PGALLOC_GFP | PGALLOC_USER_GFP;
17
18pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
19{
20 return (pte_t *)__get_free_page(PGALLOC_GFP);
21}
22
23pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
24{
25 struct page *pte;
26
27 pte = alloc_pages(__userpte_alloc_gfp, 0);
28 if (!pte)
29 return NULL;
30 if (!pgtable_page_ctor(pte)) {
31 __free_page(pte);
32 return NULL;
33 }
34 return pte;
35}
36
37static int __init setup_userpte(char *arg)
38{
39 if (!arg)
40 return -EINVAL;
41
42 /*
43 * "userpte=nohigh" disables allocation of user pagetables in
44 * high memory.
45 */
46 if (strcmp(arg, "nohigh") == 0)
47 __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
48 else
49 return -EINVAL;
50 return 0;
51}
52early_param("userpte", setup_userpte);
53
54void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
55{
56 pgtable_page_dtor(pte);
57 paravirt_release_pte(page_to_pfn(pte));
58 tlb_remove_page(tlb, pte);
59}
60
61#if PAGETABLE_LEVELS > 2
62void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
63{
64 struct page *page = virt_to_page(pmd);
65 paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
66 /*
67 * NOTE! For PAE, any changes to the top page-directory-pointer-table
68 * entries need a full cr3 reload to flush.
69 */
70#ifdef CONFIG_X86_PAE
71 tlb->need_flush_all = 1;
72#endif
73 pgtable_pmd_page_dtor(page);
74 tlb_remove_page(tlb, page);
75}
76
77#if PAGETABLE_LEVELS > 3
78void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
79{
80 paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
81 tlb_remove_page(tlb, virt_to_page(pud));
82}
83#endif /* PAGETABLE_LEVELS > 3 */
84#endif /* PAGETABLE_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
103
104static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
105{
106 BUILD_BUG_ON(sizeof(virt_to_page(pgd)->index) < sizeof(mm));
107 virt_to_page(pgd)->index = (pgoff_t)mm;
108}
109
110struct mm_struct *pgd_page_get_mm(struct page *page)
111{
112 return (struct mm_struct *)page->index;
113}
114
115static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
116{
117 /* If the pgd points to a shared pagetable level (either the
118 ptes in non-PAE, or shared PMD in PAE), then just copy the
119 references from swapper_pg_dir. */
120 if (PAGETABLE_LEVELS == 2 ||
121 (PAGETABLE_LEVELS == 3 && SHARED_KERNEL_PMD) ||
122 PAGETABLE_LEVELS == 4) {
123 clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY,
124 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
125 KERNEL_PGD_PTRS);
126 }
127
128 /* list required to sync kernel mapping updates */
129 if (!SHARED_KERNEL_PMD) {
130 pgd_set_mm(pgd, mm);
131 pgd_list_add(pgd);
132 }
133}
134
135static void pgd_dtor(pgd_t *pgd)
136{
137 if (SHARED_KERNEL_PMD)
138 return;
139
140 spin_lock(&pgd_lock);
141 pgd_list_del(pgd);
142 spin_unlock(&pgd_lock);
143}
144
145/*
146 * List of all pgd's needed for non-PAE so it can invalidate entries
147 * in both cached and uncached pgd's; not needed for PAE since the
148 * kernel pmd is shared. If PAE were not to share the pmd a similar
149 * tactic would be needed. This is essentially codepath-based locking
150 * against pageattr.c; it is the unique case in which a valid change
151 * of kernel pagetables can't be lazily synchronized by vmalloc faults.
152 * vmalloc faults work because attached pagetables are never freed.
153 * -- nyc
154 */
155
156#ifdef CONFIG_X86_PAE
157/*
158 * In PAE mode, we need to do a cr3 reload (=tlb flush) when
159 * updating the top-level pagetable entries to guarantee the
160 * processor notices the update. Since this is expensive, and
161 * all 4 top-level entries are used almost immediately in a
162 * new process's life, we just pre-populate them here.
163 *
164 * Also, if we're in a paravirt environment where the kernel pmd is
165 * not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate
166 * and initialize the kernel pmds here.
167 */
168#define PREALLOCATED_PMDS UNSHARED_PTRS_PER_PGD
169
170void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
171{
172 paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT);
173
174 /* Note: almost everything apart from _PAGE_PRESENT is
175 reserved at the pmd (PDPT) level. */
176 set_pud(pudp, __pud(__pa(pmd) | _PAGE_PRESENT));
177
178 /*
179 * According to Intel App note "TLBs, Paging-Structure Caches,
180 * and Their Invalidation", April 2007, document 317080-001,
181 * section 8.1: in PAE mode we explicitly have to flush the
182 * TLB via cr3 if the top-level pgd is changed...
183 */
184 flush_tlb_mm(mm);
185}
186#else /* !CONFIG_X86_PAE */
187
188/* No need to prepopulate any pagetable entries in non-PAE modes. */
189#define PREALLOCATED_PMDS 0
190
191#endif /* CONFIG_X86_PAE */
192
193static void free_pmds(pmd_t *pmds[])
194{
195 int i;
196
197 for(i = 0; i < PREALLOCATED_PMDS; i++)
198 if (pmds[i]) {
199 pgtable_pmd_page_dtor(virt_to_page(pmds[i]));
200 free_page((unsigned long)pmds[i]);
201 }
202}
203
204static int preallocate_pmds(pmd_t *pmds[])
205{
206 int i;
207 bool failed = false;
208
209 for(i = 0; i < PREALLOCATED_PMDS; i++) {
210 pmd_t *pmd = (pmd_t *)__get_free_page(PGALLOC_GFP);
211 if (!pmd)
212 failed = true;
213 if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
214 free_page((unsigned long)pmd);
215 pmd = NULL;
216 failed = true;
217 }
218 pmds[i] = pmd;
219 }
220
221 if (failed) {
222 free_pmds(pmds);
223 return -ENOMEM;
224 }
225
226 return 0;
227}
228
229/*
230 * Mop up any pmd pages which may still be attached to the pgd.
231 * Normally they will be freed by munmap/exit_mmap, but any pmd we
232 * preallocate which never got a corresponding vma will need to be
233 * freed manually.
234 */
235static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
236{
237 int i;
238
239 for(i = 0; i < PREALLOCATED_PMDS; i++) {
240 pgd_t pgd = pgdp[i];
241
242 if (pgd_val(pgd) != 0) {
243 pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
244
245 pgdp[i] = native_make_pgd(0);
246
247 paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT);
248 pmd_free(mm, pmd);
249 }
250 }
251}
252
253static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
254{
255 pud_t *pud;
256 int i;
257
258 if (PREALLOCATED_PMDS == 0) /* Work around gcc-3.4.x bug */
259 return;
260
261 pud = pud_offset(pgd, 0);
262
263 for (i = 0; i < PREALLOCATED_PMDS; i++, pud++) {
264 pmd_t *pmd = pmds[i];
265
266 if (i >= KERNEL_PGD_BOUNDARY)
267 memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]),
268 sizeof(pmd_t) * PTRS_PER_PMD);
269
270 pud_populate(mm, pud, pmd);
271 }
272}
273
274pgd_t *pgd_alloc(struct mm_struct *mm)
275{
276 pgd_t *pgd;
277 pmd_t *pmds[PREALLOCATED_PMDS];
278
279 pgd = (pgd_t *)__get_free_page(PGALLOC_GFP);
280
281 if (pgd == NULL)
282 goto out;
283
284 mm->pgd = pgd;
285
286 if (preallocate_pmds(pmds) != 0)
287 goto out_free_pgd;
288
289 if (paravirt_pgd_alloc(mm) != 0)
290 goto out_free_pmds;
291
292 /*
293 * Make sure that pre-populating the pmds is atomic with
294 * respect to anything walking the pgd_list, so that they
295 * never see a partially populated pgd.
296 */
297 spin_lock(&pgd_lock);
298
299 pgd_ctor(mm, pgd);
300 pgd_prepopulate_pmd(mm, pgd, pmds);
301
302 spin_unlock(&pgd_lock);
303
304 return pgd;
305
306out_free_pmds:
307 free_pmds(pmds);
308out_free_pgd:
309 free_page((unsigned long)pgd);
310out:
311 return NULL;
312}
313
314void pgd_free(struct mm_struct *mm, pgd_t *pgd)
315{
316 pgd_mop_up_pmds(mm, pgd);
317 pgd_dtor(pgd);
318 paravirt_pgd_free(mm, pgd);
319 free_page((unsigned long)pgd);
320}
321
322/*
323 * Used to set accessed or dirty bits in the page table entries
324 * on other architectures. On x86, the accessed and dirty bits
325 * are tracked by hardware. However, do_wp_page calls this function
326 * to also make the pte writeable at the same time the dirty bit is
327 * set. In that case we do actually need to write the PTE.
328 */
329int ptep_set_access_flags(struct vm_area_struct *vma,
330 unsigned long address, pte_t *ptep,
331 pte_t entry, int dirty)
332{
333 int changed = !pte_same(*ptep, entry);
334
335 if (changed && dirty) {
336 *ptep = entry;
337 pte_update_defer(vma->vm_mm, address, ptep);
338 }
339
340 return changed;
341}
342
343#ifdef CONFIG_TRANSPARENT_HUGEPAGE
344int pmdp_set_access_flags(struct vm_area_struct *vma,
345 unsigned long address, pmd_t *pmdp,
346 pmd_t entry, int dirty)
347{
348 int changed = !pmd_same(*pmdp, entry);
349
350 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
351
352 if (changed && dirty) {
353 *pmdp = entry;
354 pmd_update_defer(vma->vm_mm, address, pmdp);
355 /*
356 * We had a write-protection fault here and changed the pmd
357 * to to more permissive. No need to flush the TLB for that,
358 * #PF is architecturally guaranteed to do that and in the
359 * worst-case we'll generate a spurious fault.
360 */
361 }
362
363 return changed;
364}
365#endif
366
367int ptep_test_and_clear_young(struct vm_area_struct *vma,
368 unsigned long addr, pte_t *ptep)
369{
370 int ret = 0;
371
372 if (pte_young(*ptep))
373 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
374 (unsigned long *) &ptep->pte);
375
376 if (ret)
377 pte_update(vma->vm_mm, addr, ptep);
378
379 return ret;
380}
381
382#ifdef CONFIG_TRANSPARENT_HUGEPAGE
383int pmdp_test_and_clear_young(struct vm_area_struct *vma,
384 unsigned long addr, pmd_t *pmdp)
385{
386 int ret = 0;
387
388 if (pmd_young(*pmdp))
389 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
390 (unsigned long *)pmdp);
391
392 if (ret)
393 pmd_update(vma->vm_mm, addr, pmdp);
394
395 return ret;
396}
397#endif
398
399int ptep_clear_flush_young(struct vm_area_struct *vma,
400 unsigned long address, pte_t *ptep)
401{
402 int young;
403
404 young = ptep_test_and_clear_young(vma, address, ptep);
405 if (young)
406 flush_tlb_page(vma, address);
407
408 return young;
409}
410
411#ifdef CONFIG_TRANSPARENT_HUGEPAGE
412int pmdp_clear_flush_young(struct vm_area_struct *vma,
413 unsigned long address, pmd_t *pmdp)
414{
415 int young;
416
417 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
418
419 young = pmdp_test_and_clear_young(vma, address, pmdp);
420 if (young)
421 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
422
423 return young;
424}
425
426void pmdp_splitting_flush(struct vm_area_struct *vma,
427 unsigned long address, pmd_t *pmdp)
428{
429 int set;
430 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
431 set = !test_and_set_bit(_PAGE_BIT_SPLITTING,
432 (unsigned long *)pmdp);
433 if (set) {
434 pmd_update(vma->vm_mm, address, pmdp);
435 /* need tlb flush only to serialize against gup-fast */
436 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
437 }
438}
439#endif
440
441/**
442 * reserve_top_address - reserves a hole in the top of kernel address space
443 * @reserve - size of hole to reserve
444 *
445 * Can be used to relocate the fixmap area and poke a hole in the top
446 * of kernel address space to make room for a hypervisor.
447 */
448void __init reserve_top_address(unsigned long reserve)
449{
450#ifdef CONFIG_X86_32
451 BUG_ON(fixmaps_set > 0);
452 printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
453 (int)-reserve);
454 __FIXADDR_TOP = -reserve - PAGE_SIZE;
455#endif
456}
457
458int fixmaps_set;
459
460void __native_set_fixmap(enum fixed_addresses idx, pte_t pte)
461{
462 unsigned long address = __fix_to_virt(idx);
463
464 if (idx >= __end_of_fixed_addresses) {
465 BUG();
466 return;
467 }
468 set_pte_vaddr(address, pte);
469 fixmaps_set++;
470}
471
472void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys,
473 pgprot_t flags)
474{
475 __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags));
476}