Merge branches 'topic/fix/asoc', 'topic/fix/hda', 'topic/fix/misc' and 'topic/pci...
[linux-2.6] / arch / x86 / mm / pgtable.c
1 #include <linux/mm.h>
2 #include <asm/pgalloc.h>
3 #include <asm/pgtable.h>
4 #include <asm/tlb.h>
5 #include <asm/fixmap.h>
6
7 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
8 {
9         return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
10 }
11
12 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
13 {
14         struct page *pte;
15
16 #ifdef CONFIG_HIGHPTE
17         pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT|__GFP_ZERO, 0);
18 #else
19         pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
20 #endif
21         if (pte)
22                 pgtable_page_ctor(pte);
23         return pte;
24 }
25
26 void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
27 {
28         pgtable_page_dtor(pte);
29         paravirt_release_pte(page_to_pfn(pte));
30         tlb_remove_page(tlb, pte);
31 }
32
33 #if PAGETABLE_LEVELS > 2
34 void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
35 {
36         paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
37         tlb_remove_page(tlb, virt_to_page(pmd));
38 }
39
40 #if PAGETABLE_LEVELS > 3
41 void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
42 {
43         paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
44         tlb_remove_page(tlb, virt_to_page(pud));
45 }
46 #endif  /* PAGETABLE_LEVELS > 3 */
47 #endif  /* PAGETABLE_LEVELS > 2 */
48
49 static inline void pgd_list_add(pgd_t *pgd)
50 {
51         struct page *page = virt_to_page(pgd);
52
53         list_add(&page->lru, &pgd_list);
54 }
55
56 static inline void pgd_list_del(pgd_t *pgd)
57 {
58         struct page *page = virt_to_page(pgd);
59
60         list_del(&page->lru);
61 }
62
63 #define UNSHARED_PTRS_PER_PGD                           \
64         (SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
65
66 static void pgd_ctor(pgd_t *pgd)
67 {
68         /* If the pgd points to a shared pagetable level (either the
69            ptes in non-PAE, or shared PMD in PAE), then just copy the
70            references from swapper_pg_dir. */
71         if (PAGETABLE_LEVELS == 2 ||
72             (PAGETABLE_LEVELS == 3 && SHARED_KERNEL_PMD) ||
73             PAGETABLE_LEVELS == 4) {
74                 clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY,
75                                 swapper_pg_dir + KERNEL_PGD_BOUNDARY,
76                                 KERNEL_PGD_PTRS);
77                 paravirt_alloc_pmd_clone(__pa(pgd) >> PAGE_SHIFT,
78                                          __pa(swapper_pg_dir) >> PAGE_SHIFT,
79                                          KERNEL_PGD_BOUNDARY,
80                                          KERNEL_PGD_PTRS);
81         }
82
83         /* list required to sync kernel mapping updates */
84         if (!SHARED_KERNEL_PMD)
85                 pgd_list_add(pgd);
86 }
87
88 static void pgd_dtor(pgd_t *pgd)
89 {
90         unsigned long flags; /* can be called from interrupt context */
91
92         if (SHARED_KERNEL_PMD)
93                 return;
94
95         spin_lock_irqsave(&pgd_lock, flags);
96         pgd_list_del(pgd);
97         spin_unlock_irqrestore(&pgd_lock, flags);
98 }
99
100 /*
101  * List of all pgd's needed for non-PAE so it can invalidate entries
102  * in both cached and uncached pgd's; not needed for PAE since the
103  * kernel pmd is shared. If PAE were not to share the pmd a similar
104  * tactic would be needed. This is essentially codepath-based locking
105  * against pageattr.c; it is the unique case in which a valid change
106  * of kernel pagetables can't be lazily synchronized by vmalloc faults.
107  * vmalloc faults work because attached pagetables are never freed.
108  * -- wli
109  */
110
111 #ifdef CONFIG_X86_PAE
112 /*
113  * In PAE mode, we need to do a cr3 reload (=tlb flush) when
114  * updating the top-level pagetable entries to guarantee the
115  * processor notices the update.  Since this is expensive, and
116  * all 4 top-level entries are used almost immediately in a
117  * new process's life, we just pre-populate them here.
118  *
119  * Also, if we're in a paravirt environment where the kernel pmd is
120  * not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate
121  * and initialize the kernel pmds here.
122  */
123 #define PREALLOCATED_PMDS       UNSHARED_PTRS_PER_PGD
124
125 void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
126 {
127         paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT);
128
129         /* Note: almost everything apart from _PAGE_PRESENT is
130            reserved at the pmd (PDPT) level. */
131         set_pud(pudp, __pud(__pa(pmd) | _PAGE_PRESENT));
132
133         /*
134          * According to Intel App note "TLBs, Paging-Structure Caches,
135          * and Their Invalidation", April 2007, document 317080-001,
136          * section 8.1: in PAE mode we explicitly have to flush the
137          * TLB via cr3 if the top-level pgd is changed...
138          */
139         if (mm == current->active_mm)
140                 write_cr3(read_cr3());
141 }
142 #else  /* !CONFIG_X86_PAE */
143
144 /* No need to prepopulate any pagetable entries in non-PAE modes. */
145 #define PREALLOCATED_PMDS       0
146
147 #endif  /* CONFIG_X86_PAE */
148
149 static void free_pmds(pmd_t *pmds[])
150 {
151         int i;
152
153         for(i = 0; i < PREALLOCATED_PMDS; i++)
154                 if (pmds[i])
155                         free_page((unsigned long)pmds[i]);
156 }
157
158 static int preallocate_pmds(pmd_t *pmds[])
159 {
160         int i;
161         bool failed = false;
162
163         for(i = 0; i < PREALLOCATED_PMDS; i++) {
164                 pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
165                 if (pmd == NULL)
166                         failed = true;
167                 pmds[i] = pmd;
168         }
169
170         if (failed) {
171                 free_pmds(pmds);
172                 return -ENOMEM;
173         }
174
175         return 0;
176 }
177
178 /*
179  * Mop up any pmd pages which may still be attached to the pgd.
180  * Normally they will be freed by munmap/exit_mmap, but any pmd we
181  * preallocate which never got a corresponding vma will need to be
182  * freed manually.
183  */
184 static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
185 {
186         int i;
187
188         for(i = 0; i < PREALLOCATED_PMDS; i++) {
189                 pgd_t pgd = pgdp[i];
190
191                 if (pgd_val(pgd) != 0) {
192                         pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
193
194                         pgdp[i] = native_make_pgd(0);
195
196                         paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT);
197                         pmd_free(mm, pmd);
198                 }
199         }
200 }
201
202 static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
203 {
204         pud_t *pud;
205         unsigned long addr;
206         int i;
207
208         if (PREALLOCATED_PMDS == 0) /* Work around gcc-3.4.x bug */
209                 return;
210
211         pud = pud_offset(pgd, 0);
212
213         for (addr = i = 0; i < PREALLOCATED_PMDS;
214              i++, pud++, addr += PUD_SIZE) {
215                 pmd_t *pmd = pmds[i];
216
217                 if (i >= KERNEL_PGD_BOUNDARY)
218                         memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]),
219                                sizeof(pmd_t) * PTRS_PER_PMD);
220
221                 pud_populate(mm, pud, pmd);
222         }
223 }
224
225 pgd_t *pgd_alloc(struct mm_struct *mm)
226 {
227         pgd_t *pgd;
228         pmd_t *pmds[PREALLOCATED_PMDS];
229         unsigned long flags;
230
231         pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
232
233         if (pgd == NULL)
234                 goto out;
235
236         mm->pgd = pgd;
237
238         if (preallocate_pmds(pmds) != 0)
239                 goto out_free_pgd;
240
241         if (paravirt_pgd_alloc(mm) != 0)
242                 goto out_free_pmds;
243
244         /*
245          * Make sure that pre-populating the pmds is atomic with
246          * respect to anything walking the pgd_list, so that they
247          * never see a partially populated pgd.
248          */
249         spin_lock_irqsave(&pgd_lock, flags);
250
251         pgd_ctor(pgd);
252         pgd_prepopulate_pmd(mm, pgd, pmds);
253
254         spin_unlock_irqrestore(&pgd_lock, flags);
255
256         return pgd;
257
258 out_free_pmds:
259         free_pmds(pmds);
260 out_free_pgd:
261         free_page((unsigned long)pgd);
262 out:
263         return NULL;
264 }
265
266 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
267 {
268         pgd_mop_up_pmds(mm, pgd);
269         pgd_dtor(pgd);
270         paravirt_pgd_free(mm, pgd);
271         free_page((unsigned long)pgd);
272 }
273
274 int ptep_set_access_flags(struct vm_area_struct *vma,
275                           unsigned long address, pte_t *ptep,
276                           pte_t entry, int dirty)
277 {
278         int changed = !pte_same(*ptep, entry);
279
280         if (changed && dirty) {
281                 *ptep = entry;
282                 pte_update_defer(vma->vm_mm, address, ptep);
283                 flush_tlb_page(vma, address);
284         }
285
286         return changed;
287 }
288
289 int ptep_test_and_clear_young(struct vm_area_struct *vma,
290                               unsigned long addr, pte_t *ptep)
291 {
292         int ret = 0;
293
294         if (pte_young(*ptep))
295                 ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
296                                          (unsigned long *) &ptep->pte);
297
298         if (ret)
299                 pte_update(vma->vm_mm, addr, ptep);
300
301         return ret;
302 }
303
304 int ptep_clear_flush_young(struct vm_area_struct *vma,
305                            unsigned long address, pte_t *ptep)
306 {
307         int young;
308
309         young = ptep_test_and_clear_young(vma, address, ptep);
310         if (young)
311                 flush_tlb_page(vma, address);
312
313         return young;
314 }
315
316 int fixmaps_set;
317
318 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte)
319 {
320         unsigned long address = __fix_to_virt(idx);
321
322         if (idx >= __end_of_fixed_addresses) {
323                 BUG();
324                 return;
325         }
326         set_pte_vaddr(address, pte);
327         fixmaps_set++;
328 }
329
330 void native_set_fixmap(enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
331 {
332         __native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags));
333 }