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);
29 pgtable_page_ctor(pte);
33 static int __init setup_userpte(char *arg)
39 * "userpte=nohigh" disables allocation of user pagetables in
42 if (strcmp(arg, "nohigh") == 0)
43 __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
48 early_param("userpte", setup_userpte);
50 void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
52 pgtable_page_dtor(pte);
53 paravirt_release_pte(page_to_pfn(pte));
54 tlb_remove_page(tlb, pte);
57 #if PAGETABLE_LEVELS > 2
58 void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
60 paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
62 * NOTE! For PAE, any changes to the top page-directory-pointer-table
63 * entries need a full cr3 reload to flush.
66 tlb->need_flush_all = 1;
68 tlb_remove_page(tlb, virt_to_page(pmd));
71 #if PAGETABLE_LEVELS > 3
72 void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
74 paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
75 tlb_remove_page(tlb, virt_to_page(pud));
77 #endif /* PAGETABLE_LEVELS > 3 */
78 #endif /* PAGETABLE_LEVELS > 2 */
80 static inline void pgd_list_add(pgd_t *pgd)
82 struct page *page = virt_to_page(pgd);
84 list_add(&page->lru, &pgd_list);
87 static inline void pgd_list_del(pgd_t *pgd)
89 struct page *page = virt_to_page(pgd);
94 #define UNSHARED_PTRS_PER_PGD \
95 (SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
98 static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
100 BUILD_BUG_ON(sizeof(virt_to_page(pgd)->index) < sizeof(mm));
101 virt_to_page(pgd)->index = (pgoff_t)mm;
104 struct mm_struct *pgd_page_get_mm(struct page *page)
106 return (struct mm_struct *)page->index;
109 static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
111 /* If the pgd points to a shared pagetable level (either the
112 ptes in non-PAE, or shared PMD in PAE), then just copy the
113 references from swapper_pg_dir. */
114 if (PAGETABLE_LEVELS == 2 ||
115 (PAGETABLE_LEVELS == 3 && SHARED_KERNEL_PMD) ||
116 PAGETABLE_LEVELS == 4) {
117 clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY,
118 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
122 /* list required to sync kernel mapping updates */
123 if (!SHARED_KERNEL_PMD) {
129 static void pgd_dtor(pgd_t *pgd)
131 if (SHARED_KERNEL_PMD)
134 spin_lock(&pgd_lock);
136 spin_unlock(&pgd_lock);
140 * List of all pgd's needed for non-PAE so it can invalidate entries
141 * in both cached and uncached pgd's; not needed for PAE since the
142 * kernel pmd is shared. If PAE were not to share the pmd a similar
143 * tactic would be needed. This is essentially codepath-based locking
144 * against pageattr.c; it is the unique case in which a valid change
145 * of kernel pagetables can't be lazily synchronized by vmalloc faults.
146 * vmalloc faults work because attached pagetables are never freed.
150 #ifdef CONFIG_X86_PAE
152 * In PAE mode, we need to do a cr3 reload (=tlb flush) when
153 * updating the top-level pagetable entries to guarantee the
154 * processor notices the update. Since this is expensive, and
155 * all 4 top-level entries are used almost immediately in a
156 * new process's life, we just pre-populate them here.
158 * Also, if we're in a paravirt environment where the kernel pmd is
159 * not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate
160 * and initialize the kernel pmds here.
162 #define PREALLOCATED_PMDS UNSHARED_PTRS_PER_PGD
164 void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
166 paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT);
168 /* Note: almost everything apart from _PAGE_PRESENT is
169 reserved at the pmd (PDPT) level. */
170 set_pud(pudp, __pud(__pa(pmd) | _PAGE_PRESENT));
173 * According to Intel App note "TLBs, Paging-Structure Caches,
174 * and Their Invalidation", April 2007, document 317080-001,
175 * section 8.1: in PAE mode we explicitly have to flush the
176 * TLB via cr3 if the top-level pgd is changed...
180 #else /* !CONFIG_X86_PAE */
182 /* No need to prepopulate any pagetable entries in non-PAE modes. */
183 #define PREALLOCATED_PMDS 0
185 #endif /* CONFIG_X86_PAE */
187 static void free_pmds(pmd_t *pmds[])
191 for(i = 0; i < PREALLOCATED_PMDS; i++)
193 pgtable_pmd_page_dtor(virt_to_page(pmds[i]));
194 free_page((unsigned long)pmds[i]);
198 static int preallocate_pmds(pmd_t *pmds[])
203 for(i = 0; i < PREALLOCATED_PMDS; i++) {
204 pmd_t *pmd = (pmd_t *)__get_free_page(PGALLOC_GFP);
207 if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
208 free_page((unsigned long)pmds[i]);
224 * Mop up any pmd pages which may still be attached to the pgd.
225 * Normally they will be freed by munmap/exit_mmap, but any pmd we
226 * preallocate which never got a corresponding vma will need to be
229 static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
233 for(i = 0; i < PREALLOCATED_PMDS; i++) {
236 if (pgd_val(pgd) != 0) {
237 pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
239 pgdp[i] = native_make_pgd(0);
241 paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT);
247 static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
252 if (PREALLOCATED_PMDS == 0) /* Work around gcc-3.4.x bug */
255 pud = pud_offset(pgd, 0);
257 for (i = 0; i < PREALLOCATED_PMDS; i++, pud++) {
258 pmd_t *pmd = pmds[i];
260 if (i >= KERNEL_PGD_BOUNDARY)
261 memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]),
262 sizeof(pmd_t) * PTRS_PER_PMD);
264 pud_populate(mm, pud, pmd);
268 pgd_t *pgd_alloc(struct mm_struct *mm)
271 pmd_t *pmds[PREALLOCATED_PMDS];
273 pgd = (pgd_t *)__get_free_page(PGALLOC_GFP);
280 if (preallocate_pmds(pmds) != 0)
283 if (paravirt_pgd_alloc(mm) != 0)
287 * Make sure that pre-populating the pmds is atomic with
288 * respect to anything walking the pgd_list, so that they
289 * never see a partially populated pgd.
291 spin_lock(&pgd_lock);
294 pgd_prepopulate_pmd(mm, pgd, pmds);
296 spin_unlock(&pgd_lock);
303 free_page((unsigned long)pgd);
308 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
310 pgd_mop_up_pmds(mm, pgd);
312 paravirt_pgd_free(mm, pgd);
313 free_page((unsigned long)pgd);
317 * Used to set accessed or dirty bits in the page table entries
318 * on other architectures. On x86, the accessed and dirty bits
319 * are tracked by hardware. However, do_wp_page calls this function
320 * to also make the pte writeable at the same time the dirty bit is
321 * set. In that case we do actually need to write the PTE.
323 int ptep_set_access_flags(struct vm_area_struct *vma,
324 unsigned long address, pte_t *ptep,
325 pte_t entry, int dirty)
327 int changed = !pte_same(*ptep, entry);
329 if (changed && dirty) {
331 pte_update_defer(vma->vm_mm, address, ptep);
337 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
338 int pmdp_set_access_flags(struct vm_area_struct *vma,
339 unsigned long address, pmd_t *pmdp,
340 pmd_t entry, int dirty)
342 int changed = !pmd_same(*pmdp, entry);
344 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
346 if (changed && dirty) {
348 pmd_update_defer(vma->vm_mm, address, pmdp);
350 * We had a write-protection fault here and changed the pmd
351 * to to more permissive. No need to flush the TLB for that,
352 * #PF is architecturally guaranteed to do that and in the
353 * worst-case we'll generate a spurious fault.
361 int ptep_test_and_clear_young(struct vm_area_struct *vma,
362 unsigned long addr, pte_t *ptep)
366 if (pte_young(*ptep))
367 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
368 (unsigned long *) &ptep->pte);
371 pte_update(vma->vm_mm, addr, ptep);
376 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
377 int pmdp_test_and_clear_young(struct vm_area_struct *vma,
378 unsigned long addr, pmd_t *pmdp)
382 if (pmd_young(*pmdp))
383 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
384 (unsigned long *)pmdp);
387 pmd_update(vma->vm_mm, addr, pmdp);
393 int ptep_clear_flush_young(struct vm_area_struct *vma,
394 unsigned long address, pte_t *ptep)
398 young = ptep_test_and_clear_young(vma, address, ptep);
400 flush_tlb_page(vma, address);
405 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
406 int pmdp_clear_flush_young(struct vm_area_struct *vma,
407 unsigned long address, pmd_t *pmdp)
411 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
413 young = pmdp_test_and_clear_young(vma, address, pmdp);
415 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
420 void pmdp_splitting_flush(struct vm_area_struct *vma,
421 unsigned long address, pmd_t *pmdp)
424 VM_BUG_ON(address & ~HPAGE_PMD_MASK);
425 set = !test_and_set_bit(_PAGE_BIT_SPLITTING,
426 (unsigned long *)pmdp);
428 pmd_update(vma->vm_mm, address, pmdp);
429 /* need tlb flush only to serialize against gup-fast */
430 flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
436 * reserve_top_address - reserves a hole in the top of kernel address space
437 * @reserve - size of hole to reserve
439 * Can be used to relocate the fixmap area and poke a hole in the top
440 * of kernel address space to make room for a hypervisor.
442 void __init reserve_top_address(unsigned long reserve)
445 BUG_ON(fixmaps_set > 0);
446 printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
448 __FIXADDR_TOP = -reserve - PAGE_SIZE;
454 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte)
456 unsigned long address = __fix_to_virt(idx);
458 if (idx >= __end_of_fixed_addresses) {
462 set_pte_vaddr(address, pte);
466 void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys,
469 __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags));