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);
61 tlb_remove_page(tlb, virt_to_page(pmd));
64 #if PAGETABLE_LEVELS > 3
65 void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
67 paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
68 tlb_remove_page(tlb, virt_to_page(pud));
70 #endif /* PAGETABLE_LEVELS > 3 */
71 #endif /* PAGETABLE_LEVELS > 2 */
73 static inline void pgd_list_add(pgd_t *pgd)
75 struct page *page = virt_to_page(pgd);
77 list_add(&page->lru, &pgd_list);
80 static inline void pgd_list_del(pgd_t *pgd)
82 struct page *page = virt_to_page(pgd);
87 #define UNSHARED_PTRS_PER_PGD \
88 (SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
90 static void pgd_ctor(pgd_t *pgd)
92 /* If the pgd points to a shared pagetable level (either the
93 ptes in non-PAE, or shared PMD in PAE), then just copy the
94 references from swapper_pg_dir. */
95 if (PAGETABLE_LEVELS == 2 ||
96 (PAGETABLE_LEVELS == 3 && SHARED_KERNEL_PMD) ||
97 PAGETABLE_LEVELS == 4) {
98 clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY,
99 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
101 paravirt_alloc_pmd_clone(__pa(pgd) >> PAGE_SHIFT,
102 __pa(swapper_pg_dir) >> PAGE_SHIFT,
107 /* list required to sync kernel mapping updates */
108 if (!SHARED_KERNEL_PMD)
112 static void pgd_dtor(pgd_t *pgd)
114 unsigned long flags; /* can be called from interrupt context */
116 if (SHARED_KERNEL_PMD)
119 spin_lock_irqsave(&pgd_lock, flags);
121 spin_unlock_irqrestore(&pgd_lock, flags);
125 * List of all pgd's needed for non-PAE so it can invalidate entries
126 * in both cached and uncached pgd's; not needed for PAE since the
127 * kernel pmd is shared. If PAE were not to share the pmd a similar
128 * tactic would be needed. This is essentially codepath-based locking
129 * against pageattr.c; it is the unique case in which a valid change
130 * of kernel pagetables can't be lazily synchronized by vmalloc faults.
131 * vmalloc faults work because attached pagetables are never freed.
135 #ifdef CONFIG_X86_PAE
137 * In PAE mode, we need to do a cr3 reload (=tlb flush) when
138 * updating the top-level pagetable entries to guarantee the
139 * processor notices the update. Since this is expensive, and
140 * all 4 top-level entries are used almost immediately in a
141 * new process's life, we just pre-populate them here.
143 * Also, if we're in a paravirt environment where the kernel pmd is
144 * not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate
145 * and initialize the kernel pmds here.
147 #define PREALLOCATED_PMDS UNSHARED_PTRS_PER_PGD
149 void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
151 paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT);
153 /* Note: almost everything apart from _PAGE_PRESENT is
154 reserved at the pmd (PDPT) level. */
155 set_pud(pudp, __pud(__pa(pmd) | _PAGE_PRESENT));
158 * According to Intel App note "TLBs, Paging-Structure Caches,
159 * and Their Invalidation", April 2007, document 317080-001,
160 * section 8.1: in PAE mode we explicitly have to flush the
161 * TLB via cr3 if the top-level pgd is changed...
163 if (mm == current->active_mm)
164 write_cr3(read_cr3());
166 #else /* !CONFIG_X86_PAE */
168 /* No need to prepopulate any pagetable entries in non-PAE modes. */
169 #define PREALLOCATED_PMDS 0
171 #endif /* CONFIG_X86_PAE */
173 static void free_pmds(pmd_t *pmds[])
177 for(i = 0; i < PREALLOCATED_PMDS; i++)
179 free_page((unsigned long)pmds[i]);
182 static int preallocate_pmds(pmd_t *pmds[])
187 for(i = 0; i < PREALLOCATED_PMDS; i++) {
188 pmd_t *pmd = (pmd_t *)__get_free_page(PGALLOC_GFP);
203 * Mop up any pmd pages which may still be attached to the pgd.
204 * Normally they will be freed by munmap/exit_mmap, but any pmd we
205 * preallocate which never got a corresponding vma will need to be
208 static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
212 for(i = 0; i < PREALLOCATED_PMDS; i++) {
215 if (pgd_val(pgd) != 0) {
216 pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
218 pgdp[i] = native_make_pgd(0);
220 paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT);
226 static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
232 if (PREALLOCATED_PMDS == 0) /* Work around gcc-3.4.x bug */
235 pud = pud_offset(pgd, 0);
237 for (addr = i = 0; i < PREALLOCATED_PMDS;
238 i++, pud++, addr += PUD_SIZE) {
239 pmd_t *pmd = pmds[i];
241 if (i >= KERNEL_PGD_BOUNDARY)
242 memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]),
243 sizeof(pmd_t) * PTRS_PER_PMD);
245 pud_populate(mm, pud, pmd);
249 pgd_t *pgd_alloc(struct mm_struct *mm)
252 pmd_t *pmds[PREALLOCATED_PMDS];
255 pgd = (pgd_t *)__get_free_page(PGALLOC_GFP);
262 if (preallocate_pmds(pmds) != 0)
265 if (paravirt_pgd_alloc(mm) != 0)
269 * Make sure that pre-populating the pmds is atomic with
270 * respect to anything walking the pgd_list, so that they
271 * never see a partially populated pgd.
273 spin_lock_irqsave(&pgd_lock, flags);
276 pgd_prepopulate_pmd(mm, pgd, pmds);
278 spin_unlock_irqrestore(&pgd_lock, flags);
285 free_page((unsigned long)pgd);
290 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
292 pgd_mop_up_pmds(mm, pgd);
294 paravirt_pgd_free(mm, pgd);
295 free_page((unsigned long)pgd);
298 int ptep_set_access_flags(struct vm_area_struct *vma,
299 unsigned long address, pte_t *ptep,
300 pte_t entry, int dirty)
302 int changed = !pte_same(*ptep, entry);
304 if (changed && dirty) {
306 pte_update_defer(vma->vm_mm, address, ptep);
307 flush_tlb_page(vma, address);
313 int ptep_test_and_clear_young(struct vm_area_struct *vma,
314 unsigned long addr, pte_t *ptep)
318 if (pte_young(*ptep))
319 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
320 (unsigned long *) &ptep->pte);
323 pte_update(vma->vm_mm, addr, ptep);
328 int ptep_clear_flush_young(struct vm_area_struct *vma,
329 unsigned long address, pte_t *ptep)
333 young = ptep_test_and_clear_young(vma, address, ptep);
335 flush_tlb_page(vma, address);
341 * reserve_top_address - reserves a hole in the top of kernel address space
342 * @reserve - size of hole to reserve
344 * Can be used to relocate the fixmap area and poke a hole in the top
345 * of kernel address space to make room for a hypervisor.
347 void __init reserve_top_address(unsigned long reserve)
350 BUG_ON(fixmaps_set > 0);
351 printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
353 __FIXADDR_TOP = -reserve - PAGE_SIZE;
359 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte)
361 unsigned long address = __fix_to_virt(idx);
363 if (idx >= __end_of_fixed_addresses) {
367 set_pte_vaddr(address, pte);
371 void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys,
374 __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags));