3 #include <asm/pgalloc.h>
4 #include <asm/pgtable.h>
6 #include <asm/fixmap.h>
8 #define PGALLOC_GFP GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO
11 #define PGALLOC_USER_GFP __GFP_HIGHMEM
13 #define PGALLOC_USER_GFP 0
16 gfp_t __userpte_alloc_gfp = PGALLOC_GFP | PGALLOC_USER_GFP;
18 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
20 return (pte_t *)__get_free_page(PGALLOC_GFP);
23 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
27 pte = alloc_pages(__userpte_alloc_gfp, 0);
30 if (!pgtable_page_ctor(pte)) {
37 static int __init setup_userpte(char *arg)
43 * "userpte=nohigh" disables allocation of user pagetables in
46 if (strcmp(arg, "nohigh") == 0)
47 __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
52 early_param("userpte", setup_userpte);
54 void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
56 pgtable_page_dtor(pte);
57 paravirt_release_pte(page_to_pfn(pte));
58 tlb_remove_page(tlb, pte);
61 #if PAGETABLE_LEVELS > 2
62 void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
64 struct page *page = virt_to_page(pmd);
65 paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
67 * NOTE! For PAE, any changes to the top page-directory-pointer-table
68 * entries need a full cr3 reload to flush.
71 tlb->need_flush_all = 1;
73 pgtable_pmd_page_dtor(page);
74 tlb_remove_page(tlb, page);
77 #if PAGETABLE_LEVELS > 3
78 void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
80 paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
81 tlb_remove_page(tlb, virt_to_page(pud));
83 #endif /* PAGETABLE_LEVELS > 3 */
84 #endif /* PAGETABLE_LEVELS > 2 */
86 static inline void pgd_list_add(pgd_t *pgd)
88 struct page *page = virt_to_page(pgd);
90 list_add(&page->lru, &pgd_list);
93 static inline void pgd_list_del(pgd_t *pgd)
95 struct page *page = virt_to_page(pgd);
100 #define UNSHARED_PTRS_PER_PGD \
101 (SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
104 static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
106 BUILD_BUG_ON(sizeof(virt_to_page(pgd)->index) < sizeof(mm));
107 virt_to_page(pgd)->index = (pgoff_t)mm;
110 struct mm_struct *pgd_page_get_mm(struct page *page)
112 return (struct mm_struct *)page->index;
115 static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
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,
128 /* list required to sync kernel mapping updates */
129 if (!SHARED_KERNEL_PMD) {
135 static void pgd_dtor(pgd_t *pgd)
137 if (SHARED_KERNEL_PMD)
140 spin_lock(&pgd_lock);
142 spin_unlock(&pgd_lock);
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.
156 #ifdef CONFIG_X86_PAE
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.
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.
168 #define PREALLOCATED_PMDS UNSHARED_PTRS_PER_PGD
170 void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
172 paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT);
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));
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...
186 #else /* !CONFIG_X86_PAE */
188 /* No need to prepopulate any pagetable entries in non-PAE modes. */
189 #define PREALLOCATED_PMDS 0
191 #endif /* CONFIG_X86_PAE */
193 static void free_pmds(struct mm_struct *mm, pmd_t *pmds[])
197 for(i = 0; i < PREALLOCATED_PMDS; i++)
199 pgtable_pmd_page_dtor(virt_to_page(pmds[i]));
200 free_page((unsigned long)pmds[i]);
205 static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[])
210 for(i = 0; i < PREALLOCATED_PMDS; i++) {
211 pmd_t *pmd = (pmd_t *)__get_free_page(PGALLOC_GFP);
214 if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
215 free_page((unsigned long)pmd);
233 * Mop up any pmd pages which may still be attached to the pgd.
234 * Normally they will be freed by munmap/exit_mmap, but any pmd we
235 * preallocate which never got a corresponding vma will need to be
238 static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
242 for(i = 0; i < PREALLOCATED_PMDS; i++) {
245 if (pgd_val(pgd) != 0) {
246 pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
248 pgdp[i] = native_make_pgd(0);
250 paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT);
257 static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
262 if (PREALLOCATED_PMDS == 0) /* Work around gcc-3.4.x bug */
265 pud = pud_offset(pgd, 0);
267 for (i = 0; i < PREALLOCATED_PMDS; i++, pud++) {
268 pmd_t *pmd = pmds[i];
270 if (i >= KERNEL_PGD_BOUNDARY)
271 memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]),
272 sizeof(pmd_t) * PTRS_PER_PMD);
274 pud_populate(mm, pud, pmd);
278 pgd_t *pgd_alloc(struct mm_struct *mm)
281 pmd_t *pmds[PREALLOCATED_PMDS];
283 pgd = (pgd_t *)__get_free_page(PGALLOC_GFP);
290 if (preallocate_pmds(mm, pmds) != 0)
293 if (paravirt_pgd_alloc(mm) != 0)
297 * Make sure that pre-populating the pmds is atomic with
298 * respect to anything walking the pgd_list, so that they
299 * never see a partially populated pgd.
301 spin_lock(&pgd_lock);
304 pgd_prepopulate_pmd(mm, pgd, pmds);
306 spin_unlock(&pgd_lock);
313 free_page((unsigned long)pgd);
318 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
320 pgd_mop_up_pmds(mm, pgd);
322 paravirt_pgd_free(mm, pgd);
323 free_page((unsigned long)pgd);
327 * Used to set accessed or dirty bits in the page table entries
328 * on other architectures. On x86, the accessed and dirty bits
329 * are tracked by hardware. However, do_wp_page calls this function
330 * to also make the pte writeable at the same time the dirty bit is
331 * set. In that case we do actually need to write the PTE.
333 int ptep_set_access_flags(struct vm_area_struct *vma,
334 unsigned long address, pte_t *ptep,
335 pte_t entry, int dirty)
337 int changed = !pte_same(*ptep, entry);
339 if (changed && dirty) {
341 pte_update_defer(vma->vm_mm, address, ptep);
347 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
348 int pmdp_set_access_flags(struct vm_area_struct *vma,
349 unsigned long address, pmd_t *pmdp,
350 pmd_t entry, int dirty)
352 int changed = !pmd_same(*pmdp, entry);
354 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
356 if (changed && dirty) {
358 pmd_update_defer(vma->vm_mm, address, pmdp);
360 * We had a write-protection fault here and changed the pmd
361 * to to more permissive. No need to flush the TLB for that,
362 * #PF is architecturally guaranteed to do that and in the
363 * worst-case we'll generate a spurious fault.
371 int ptep_test_and_clear_young(struct vm_area_struct *vma,
372 unsigned long addr, pte_t *ptep)
376 if (pte_young(*ptep))
377 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
378 (unsigned long *) &ptep->pte);
381 pte_update(vma->vm_mm, addr, ptep);
386 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
387 int pmdp_test_and_clear_young(struct vm_area_struct *vma,
388 unsigned long addr, pmd_t *pmdp)
392 if (pmd_young(*pmdp))
393 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
394 (unsigned long *)pmdp);
397 pmd_update(vma->vm_mm, addr, pmdp);
403 int ptep_clear_flush_young(struct vm_area_struct *vma,
404 unsigned long address, pte_t *ptep)
407 * On x86 CPUs, clearing the accessed bit without a TLB flush
408 * doesn't cause data corruption. [ It could cause incorrect
409 * page aging and the (mistaken) reclaim of hot pages, but the
410 * chance of that should be relatively low. ]
412 * So as a performance optimization don't flush the TLB when
413 * clearing the accessed bit, it will eventually be flushed by
414 * a context switch or a VM operation anyway. [ In the rare
415 * event of it not getting flushed for a long time the delay
416 * shouldn't really matter because there's no real memory
417 * pressure for swapout to react to. ]
419 return ptep_test_and_clear_young(vma, address, ptep);
422 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
423 int pmdp_clear_flush_young(struct vm_area_struct *vma,
424 unsigned long address, pmd_t *pmdp)
428 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
430 young = pmdp_test_and_clear_young(vma, address, pmdp);
432 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
437 void pmdp_splitting_flush(struct vm_area_struct *vma,
438 unsigned long address, pmd_t *pmdp)
441 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
442 set = !test_and_set_bit(_PAGE_BIT_SPLITTING,
443 (unsigned long *)pmdp);
445 pmd_update(vma->vm_mm, address, pmdp);
446 /* need tlb flush only to serialize against gup-fast */
447 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
453 * reserve_top_address - reserves a hole in the top of kernel address space
454 * @reserve - size of hole to reserve
456 * Can be used to relocate the fixmap area and poke a hole in the top
457 * of kernel address space to make room for a hypervisor.
459 void __init reserve_top_address(unsigned long reserve)
462 BUG_ON(fixmaps_set > 0);
463 __FIXADDR_TOP = round_down(-reserve, 1 << PMD_SHIFT) - PAGE_SIZE;
464 printk(KERN_INFO "Reserving virtual address space above 0x%08lx (rounded to 0x%08lx)\n",
465 -reserve, __FIXADDR_TOP + PAGE_SIZE);
471 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte)
473 unsigned long address = __fix_to_virt(idx);
475 if (idx >= __end_of_fixed_addresses) {
479 set_pte_vaddr(address, pte);
483 void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys,
486 __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags));