0fd9d7f77786193a7fc77f18e1093fa150118d84
[sfrench/cifs-2.6.git] / arch / x86 / mm / init_64.c
1 /*
2  *  linux/arch/x86_64/mm/init.c
3  *
4  *  Copyright (C) 1995  Linus Torvalds
5  *  Copyright (C) 2000  Pavel Machek <pavel@suse.cz>
6  *  Copyright (C) 2002,2003 Andi Kleen <ak@suse.de>
7  */
8
9 #include <linux/signal.h>
10 #include <linux/sched.h>
11 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/string.h>
14 #include <linux/types.h>
15 #include <linux/ptrace.h>
16 #include <linux/mman.h>
17 #include <linux/mm.h>
18 #include <linux/swap.h>
19 #include <linux/smp.h>
20 #include <linux/init.h>
21 #include <linux/pagemap.h>
22 #include <linux/bootmem.h>
23 #include <linux/proc_fs.h>
24 #include <linux/pci.h>
25 #include <linux/pfn.h>
26 #include <linux/poison.h>
27 #include <linux/dma-mapping.h>
28 #include <linux/module.h>
29 #include <linux/memory_hotplug.h>
30 #include <linux/nmi.h>
31
32 #include <asm/processor.h>
33 #include <asm/system.h>
34 #include <asm/uaccess.h>
35 #include <asm/pgtable.h>
36 #include <asm/pgalloc.h>
37 #include <asm/dma.h>
38 #include <asm/fixmap.h>
39 #include <asm/e820.h>
40 #include <asm/apic.h>
41 #include <asm/tlb.h>
42 #include <asm/mmu_context.h>
43 #include <asm/proto.h>
44 #include <asm/smp.h>
45 #include <asm/sections.h>
46 #include <asm/kdebug.h>
47 #include <asm/numa.h>
48
49 #ifndef Dprintk
50 #define Dprintk(x...)
51 #endif
52
53 const struct dma_mapping_ops* dma_ops;
54 EXPORT_SYMBOL(dma_ops);
55
56 static unsigned long dma_reserve __initdata;
57
58 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
59
60 /*
61  * NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the
62  * physical space so we can cache the place of the first one and move
63  * around without checking the pgd every time.
64  */
65
66 void show_mem(void)
67 {
68         long i, total = 0, reserved = 0;
69         long shared = 0, cached = 0;
70         pg_data_t *pgdat;
71         struct page *page;
72
73         printk(KERN_INFO "Mem-info:\n");
74         show_free_areas();
75         printk(KERN_INFO "Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
76
77         for_each_online_pgdat(pgdat) {
78                for (i = 0; i < pgdat->node_spanned_pages; ++i) {
79                         /* this loop can take a while with 256 GB and 4k pages
80                            so update the NMI watchdog */
81                         if (unlikely(i % MAX_ORDER_NR_PAGES == 0)) {
82                                 touch_nmi_watchdog();
83                         }
84                         if (!pfn_valid(pgdat->node_start_pfn + i))
85                                 continue;
86                         page = pfn_to_page(pgdat->node_start_pfn + i);
87                         total++;
88                         if (PageReserved(page))
89                                 reserved++;
90                         else if (PageSwapCache(page))
91                                 cached++;
92                         else if (page_count(page))
93                                 shared += page_count(page) - 1;
94                }
95         }
96         printk(KERN_INFO "%lu pages of RAM\n", total);
97         printk(KERN_INFO "%lu reserved pages\n",reserved);
98         printk(KERN_INFO "%lu pages shared\n",shared);
99         printk(KERN_INFO "%lu pages swap cached\n",cached);
100 }
101
102 int after_bootmem;
103
104 static __init void *spp_getpage(void)
105
106         void *ptr;
107         if (after_bootmem)
108                 ptr = (void *) get_zeroed_page(GFP_ATOMIC); 
109         else
110                 ptr = alloc_bootmem_pages(PAGE_SIZE);
111         if (!ptr || ((unsigned long)ptr & ~PAGE_MASK))
112                 panic("set_pte_phys: cannot allocate page data %s\n", after_bootmem?"after bootmem":"");
113
114         Dprintk("spp_getpage %p\n", ptr);
115         return ptr;
116
117
118 static __init void set_pte_phys(unsigned long vaddr,
119                          unsigned long phys, pgprot_t prot)
120 {
121         pgd_t *pgd;
122         pud_t *pud;
123         pmd_t *pmd;
124         pte_t *pte, new_pte;
125
126         Dprintk("set_pte_phys %lx to %lx\n", vaddr, phys);
127
128         pgd = pgd_offset_k(vaddr);
129         if (pgd_none(*pgd)) {
130                 printk("PGD FIXMAP MISSING, it should be setup in head.S!\n");
131                 return;
132         }
133         pud = pud_offset(pgd, vaddr);
134         if (pud_none(*pud)) {
135                 pmd = (pmd_t *) spp_getpage(); 
136                 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE | _PAGE_USER));
137                 if (pmd != pmd_offset(pud, 0)) {
138                         printk("PAGETABLE BUG #01! %p <-> %p\n", pmd, pmd_offset(pud,0));
139                         return;
140                 }
141         }
142         pmd = pmd_offset(pud, vaddr);
143         if (pmd_none(*pmd)) {
144                 pte = (pte_t *) spp_getpage();
145                 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE | _PAGE_USER));
146                 if (pte != pte_offset_kernel(pmd, 0)) {
147                         printk("PAGETABLE BUG #02!\n");
148                         return;
149                 }
150         }
151         new_pte = pfn_pte(phys >> PAGE_SHIFT, prot);
152
153         pte = pte_offset_kernel(pmd, vaddr);
154         if (!pte_none(*pte) &&
155             pte_val(*pte) != (pte_val(new_pte) & __supported_pte_mask))
156                 pte_ERROR(*pte);
157         set_pte(pte, new_pte);
158
159         /*
160          * It's enough to flush this one mapping.
161          * (PGE mappings get flushed as well)
162          */
163         __flush_tlb_one(vaddr);
164 }
165
166 /* NOTE: this is meant to be run only at boot */
167 void __init 
168 __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t prot)
169 {
170         unsigned long address = __fix_to_virt(idx);
171
172         if (idx >= __end_of_fixed_addresses) {
173                 printk("Invalid __set_fixmap\n");
174                 return;
175         }
176         set_pte_phys(address, phys, prot);
177 }
178
179 static unsigned long __initdata table_start;
180 static unsigned long __meminitdata table_end;
181
182 static __meminit void *alloc_low_page(unsigned long *phys)
183
184         unsigned long pfn = table_end++;
185         void *adr;
186
187         if (after_bootmem) {
188                 adr = (void *)get_zeroed_page(GFP_ATOMIC);
189                 *phys = __pa(adr);
190                 return adr;
191         }
192
193         if (pfn >= end_pfn) 
194                 panic("alloc_low_page: ran out of memory"); 
195
196         adr = early_ioremap(pfn * PAGE_SIZE, PAGE_SIZE);
197         memset(adr, 0, PAGE_SIZE);
198         *phys  = pfn * PAGE_SIZE;
199         return adr;
200 }
201
202 static __meminit void unmap_low_page(void *adr)
203
204
205         if (after_bootmem)
206                 return;
207
208         early_iounmap(adr, PAGE_SIZE);
209
210
211 /* Must run before zap_low_mappings */
212 __meminit void *early_ioremap(unsigned long addr, unsigned long size)
213 {
214         unsigned long vaddr;
215         pmd_t *pmd, *last_pmd;
216         int i, pmds;
217
218         pmds = ((addr & ~PMD_MASK) + size + ~PMD_MASK) / PMD_SIZE;
219         vaddr = __START_KERNEL_map;
220         pmd = level2_kernel_pgt;
221         last_pmd = level2_kernel_pgt + PTRS_PER_PMD - 1;
222         for (; pmd <= last_pmd; pmd++, vaddr += PMD_SIZE) {
223                 for (i = 0; i < pmds; i++) {
224                         if (pmd_present(pmd[i]))
225                                 goto next;
226                 }
227                 vaddr += addr & ~PMD_MASK;
228                 addr &= PMD_MASK;
229                 for (i = 0; i < pmds; i++, addr += PMD_SIZE)
230                         set_pmd(pmd+i, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
231                 __flush_tlb();
232                 return (void *)vaddr;
233         next:
234                 ;
235         }
236         printk("early_ioremap(0x%lx, %lu) failed\n", addr, size);
237         return NULL;
238 }
239
240 /* To avoid virtual aliases later */
241 __meminit void early_iounmap(void *addr, unsigned long size)
242 {
243         unsigned long vaddr;
244         pmd_t *pmd;
245         int i, pmds;
246
247         vaddr = (unsigned long)addr;
248         pmds = ((vaddr & ~PMD_MASK) + size + ~PMD_MASK) / PMD_SIZE;
249         pmd = level2_kernel_pgt + pmd_index(vaddr);
250         for (i = 0; i < pmds; i++)
251                 pmd_clear(pmd + i);
252         __flush_tlb();
253 }
254
255 static void __meminit
256 phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end)
257 {
258         int i = pmd_index(address);
259
260         for (; i < PTRS_PER_PMD; i++, address += PMD_SIZE) {
261                 unsigned long entry;
262                 pmd_t *pmd = pmd_page + pmd_index(address);
263
264                 if (address >= end) {
265                         if (!after_bootmem)
266                                 for (; i < PTRS_PER_PMD; i++, pmd++)
267                                         set_pmd(pmd, __pmd(0));
268                         break;
269                 }
270
271                 if (pmd_val(*pmd))
272                         continue;
273
274                 entry = __PAGE_KERNEL_LARGE|_PAGE_GLOBAL|address;
275                 entry &= __supported_pte_mask;
276                 set_pmd(pmd, __pmd(entry));
277         }
278 }
279
280 static void __meminit
281 phys_pmd_update(pud_t *pud, unsigned long address, unsigned long end)
282 {
283         pmd_t *pmd = pmd_offset(pud,0);
284         spin_lock(&init_mm.page_table_lock);
285         phys_pmd_init(pmd, address, end);
286         spin_unlock(&init_mm.page_table_lock);
287         __flush_tlb_all();
288 }
289
290 static void __meminit phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end)
291
292         int i = pud_index(addr);
293
294
295         for (; i < PTRS_PER_PUD; i++, addr = (addr & PUD_MASK) + PUD_SIZE ) {
296                 unsigned long pmd_phys;
297                 pud_t *pud = pud_page + pud_index(addr);
298                 pmd_t *pmd;
299
300                 if (addr >= end)
301                         break;
302
303                 if (!after_bootmem && !e820_any_mapped(addr,addr+PUD_SIZE,0)) {
304                         set_pud(pud, __pud(0)); 
305                         continue;
306                 } 
307
308                 if (pud_val(*pud)) {
309                         phys_pmd_update(pud, addr, end);
310                         continue;
311                 }
312
313                 pmd = alloc_low_page(&pmd_phys);
314                 spin_lock(&init_mm.page_table_lock);
315                 set_pud(pud, __pud(pmd_phys | _KERNPG_TABLE));
316                 phys_pmd_init(pmd, addr, end);
317                 spin_unlock(&init_mm.page_table_lock);
318                 unmap_low_page(pmd);
319         }
320         __flush_tlb();
321
322
323 static void __init find_early_table_space(unsigned long end)
324 {
325         unsigned long puds, pmds, tables, start;
326
327         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
328         pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
329         tables = round_up(puds * sizeof(pud_t), PAGE_SIZE) +
330                  round_up(pmds * sizeof(pmd_t), PAGE_SIZE);
331
332         /* RED-PEN putting page tables only on node 0 could
333            cause a hotspot and fill up ZONE_DMA. The page tables
334            need roughly 0.5KB per GB. */
335         start = 0x8000;
336         table_start = find_e820_area(start, end, tables);
337         if (table_start == -1UL)
338                 panic("Cannot find space for the kernel page tables");
339
340         table_start >>= PAGE_SHIFT;
341         table_end = table_start;
342
343         early_printk("kernel direct mapping tables up to %lx @ %lx-%lx\n",
344                 end, table_start << PAGE_SHIFT,
345                 (table_start << PAGE_SHIFT) + tables);
346 }
347
348 /* Setup the direct mapping of the physical memory at PAGE_OFFSET.
349    This runs before bootmem is initialized and gets pages directly from the 
350    physical memory. To access them they are temporarily mapped. */
351 void __init_refok init_memory_mapping(unsigned long start, unsigned long end)
352
353         unsigned long next; 
354
355         Dprintk("init_memory_mapping\n");
356
357         /* 
358          * Find space for the kernel direct mapping tables.
359          * Later we should allocate these tables in the local node of the memory
360          * mapped.  Unfortunately this is done currently before the nodes are 
361          * discovered.
362          */
363         if (!after_bootmem)
364                 find_early_table_space(end);
365
366         start = (unsigned long)__va(start);
367         end = (unsigned long)__va(end);
368
369         for (; start < end; start = next) {
370                 unsigned long pud_phys; 
371                 pgd_t *pgd = pgd_offset_k(start);
372                 pud_t *pud;
373
374                 if (after_bootmem)
375                         pud = pud_offset(pgd, start & PGDIR_MASK);
376                 else
377                         pud = alloc_low_page(&pud_phys);
378
379                 next = start + PGDIR_SIZE;
380                 if (next > end) 
381                         next = end; 
382                 phys_pud_init(pud, __pa(start), __pa(next));
383                 if (!after_bootmem)
384                         set_pgd(pgd_offset_k(start), mk_kernel_pgd(pud_phys));
385                 unmap_low_page(pud);
386         } 
387
388         if (!after_bootmem)
389                 mmu_cr4_features = read_cr4();
390         __flush_tlb_all();
391
392         reserve_early(table_start << PAGE_SHIFT, table_end << PAGE_SHIFT);
393 }
394
395 #ifndef CONFIG_NUMA
396 void __init paging_init(void)
397 {
398         unsigned long max_zone_pfns[MAX_NR_ZONES];
399         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
400         max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
401         max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
402         max_zone_pfns[ZONE_NORMAL] = end_pfn;
403
404         memory_present(0, 0, end_pfn);
405         sparse_init();
406         free_area_init_nodes(max_zone_pfns);
407 }
408 #endif
409
410 /* Unmap a kernel mapping if it exists. This is useful to avoid prefetches
411    from the CPU leading to inconsistent cache lines. address and size
412    must be aligned to 2MB boundaries. 
413    Does nothing when the mapping doesn't exist. */
414 void __init clear_kernel_mapping(unsigned long address, unsigned long size) 
415 {
416         unsigned long end = address + size;
417
418         BUG_ON(address & ~LARGE_PAGE_MASK);
419         BUG_ON(size & ~LARGE_PAGE_MASK); 
420         
421         for (; address < end; address += LARGE_PAGE_SIZE) { 
422                 pgd_t *pgd = pgd_offset_k(address);
423                 pud_t *pud;
424                 pmd_t *pmd;
425                 if (pgd_none(*pgd))
426                         continue;
427                 pud = pud_offset(pgd, address);
428                 if (pud_none(*pud))
429                         continue; 
430                 pmd = pmd_offset(pud, address);
431                 if (!pmd || pmd_none(*pmd))
432                         continue; 
433                 if (0 == (pmd_val(*pmd) & _PAGE_PSE)) { 
434                         /* Could handle this, but it should not happen currently. */
435                         printk(KERN_ERR 
436                "clear_kernel_mapping: mapping has been split. will leak memory\n"); 
437                         pmd_ERROR(*pmd); 
438                 }
439                 set_pmd(pmd, __pmd(0));                 
440         }
441         __flush_tlb_all();
442
443
444 /*
445  * Memory hotplug specific functions
446  */
447 void online_page(struct page *page)
448 {
449         ClearPageReserved(page);
450         init_page_count(page);
451         __free_page(page);
452         totalram_pages++;
453         num_physpages++;
454 }
455
456 #ifdef CONFIG_MEMORY_HOTPLUG
457 /*
458  * Memory is added always to NORMAL zone. This means you will never get
459  * additional DMA/DMA32 memory.
460  */
461 int arch_add_memory(int nid, u64 start, u64 size)
462 {
463         struct pglist_data *pgdat = NODE_DATA(nid);
464         struct zone *zone = pgdat->node_zones + ZONE_NORMAL;
465         unsigned long start_pfn = start >> PAGE_SHIFT;
466         unsigned long nr_pages = size >> PAGE_SHIFT;
467         int ret;
468
469         init_memory_mapping(start, (start + size -1));
470
471         ret = __add_pages(zone, start_pfn, nr_pages);
472         if (ret)
473                 goto error;
474
475         return ret;
476 error:
477         printk("%s: Problem encountered in __add_pages!\n", __func__);
478         return ret;
479 }
480 EXPORT_SYMBOL_GPL(arch_add_memory);
481
482 #if !defined(CONFIG_ACPI_NUMA) && defined(CONFIG_NUMA)
483 int memory_add_physaddr_to_nid(u64 start)
484 {
485         return 0;
486 }
487 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
488 #endif
489
490 #endif /* CONFIG_MEMORY_HOTPLUG */
491
492 static struct kcore_list kcore_mem, kcore_vmalloc, kcore_kernel, kcore_modules,
493                          kcore_vsyscall;
494
495 void __init mem_init(void)
496 {
497         long codesize, reservedpages, datasize, initsize;
498
499         pci_iommu_alloc();
500
501         /* clear_bss() already clear the empty_zero_page */
502
503         /* temporary debugging - double check it's true: */
504         {
505                 int i;
506
507                 for (i = 0; i < 1024; i++)
508                         WARN_ON_ONCE(empty_zero_page[i]);
509         }
510
511         reservedpages = 0;
512
513         /* this will put all low memory onto the freelists */
514 #ifdef CONFIG_NUMA
515         totalram_pages = numa_free_all_bootmem();
516 #else
517         totalram_pages = free_all_bootmem();
518 #endif
519         reservedpages = end_pfn - totalram_pages -
520                                         absent_pages_in_range(0, end_pfn);
521
522         after_bootmem = 1;
523
524         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
525         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
526         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
527
528         /* Register memory areas for /proc/kcore */
529         kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT); 
530         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START, 
531                    VMALLOC_END-VMALLOC_START);
532         kclist_add(&kcore_kernel, &_stext, _end - _stext);
533         kclist_add(&kcore_modules, (void *)MODULES_VADDR, MODULES_LEN);
534         kclist_add(&kcore_vsyscall, (void *)VSYSCALL_START, 
535                                  VSYSCALL_END - VSYSCALL_START);
536
537         printk("Memory: %luk/%luk available (%ldk kernel code, %ldk reserved, %ldk data, %ldk init)\n",
538                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
539                 end_pfn << (PAGE_SHIFT-10),
540                 codesize >> 10,
541                 reservedpages << (PAGE_SHIFT-10),
542                 datasize >> 10,
543                 initsize >> 10);
544 }
545
546 void free_init_pages(char *what, unsigned long begin, unsigned long end)
547 {
548         unsigned long addr;
549
550         if (begin >= end)
551                 return;
552
553         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
554         for (addr = begin; addr < end; addr += PAGE_SIZE) {
555                 ClearPageReserved(virt_to_page(addr));
556                 init_page_count(virt_to_page(addr));
557                 memset((void *)(addr & ~(PAGE_SIZE-1)),
558                         POISON_FREE_INITMEM, PAGE_SIZE);
559                 if (addr >= __START_KERNEL_map)
560                         change_page_attr_addr(addr, 1, __pgprot(0));
561                 free_page(addr);
562                 totalram_pages++;
563         }
564         if (addr > __START_KERNEL_map)
565                 global_flush_tlb();
566 }
567
568 void free_initmem(void)
569 {
570         free_init_pages("unused kernel memory",
571                         (unsigned long)(&__init_begin),
572                         (unsigned long)(&__init_end));
573 }
574
575 #ifdef CONFIG_DEBUG_RODATA
576
577 void mark_rodata_ro(void)
578 {
579         unsigned long start = (unsigned long)_stext, end;
580
581 #ifdef CONFIG_HOTPLUG_CPU
582         /* It must still be possible to apply SMP alternatives. */
583         if (num_possible_cpus() > 1)
584                 start = (unsigned long)_etext;
585 #endif
586
587 #ifdef CONFIG_KPROBES
588         start = (unsigned long)__start_rodata;
589 #endif
590         
591         end = (unsigned long)__end_rodata;
592         start = (start + PAGE_SIZE - 1) & PAGE_MASK;
593         end &= PAGE_MASK;
594         if (end <= start)
595                 return;
596
597         change_page_attr_addr(start, (end - start) >> PAGE_SHIFT, PAGE_KERNEL_RO);
598
599         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
600                (end - start) >> 10);
601
602         /*
603          * change_page_attr_addr() requires a global_flush_tlb() call after it.
604          * We do this after the printk so that if something went wrong in the
605          * change, the printk gets out at least to give a better debug hint
606          * of who is the culprit.
607          */
608         global_flush_tlb();
609
610 #ifdef CONFIG_CPA_DEBUG
611         printk("Testing CPA: undo %lx-%lx\n", start, end);
612         change_page_attr_addr(start, (end - start) >> PAGE_SHIFT, PAGE_KERNEL);
613         global_flush_tlb();
614
615         printk("Testing CPA: again\n");
616         change_page_attr_addr(start, (end - start) >> PAGE_SHIFT, PAGE_KERNEL_RO);
617         global_flush_tlb();
618 #endif
619 }
620 #endif
621
622 #ifdef CONFIG_BLK_DEV_INITRD
623 void free_initrd_mem(unsigned long start, unsigned long end)
624 {
625         free_init_pages("initrd memory", start, end);
626 }
627 #endif
628
629 void __init reserve_bootmem_generic(unsigned long phys, unsigned len) 
630
631 #ifdef CONFIG_NUMA
632         int nid = phys_to_nid(phys);
633 #endif
634         unsigned long pfn = phys >> PAGE_SHIFT;
635         if (pfn >= end_pfn) {
636                 /* This can happen with kdump kernels when accessing firmware
637                    tables. */
638                 if (pfn < end_pfn_map)
639                         return;
640                 printk(KERN_ERR "reserve_bootmem: illegal reserve %lx %u\n",
641                                 phys, len);
642                 return;
643         }
644
645         /* Should check here against the e820 map to avoid double free */
646 #ifdef CONFIG_NUMA
647         reserve_bootmem_node(NODE_DATA(nid), phys, len);
648 #else                   
649         reserve_bootmem(phys, len);    
650 #endif
651         if (phys+len <= MAX_DMA_PFN*PAGE_SIZE) {
652                 dma_reserve += len / PAGE_SIZE;
653                 set_dma_reserve(dma_reserve);
654         }
655 }
656
657 int kern_addr_valid(unsigned long addr) 
658
659         unsigned long above = ((long)addr) >> __VIRTUAL_MASK_SHIFT;
660        pgd_t *pgd;
661        pud_t *pud;
662        pmd_t *pmd;
663        pte_t *pte;
664
665         if (above != 0 && above != -1UL)
666                 return 0; 
667         
668         pgd = pgd_offset_k(addr);
669         if (pgd_none(*pgd))
670                 return 0;
671
672         pud = pud_offset(pgd, addr);
673         if (pud_none(*pud))
674                 return 0; 
675
676         pmd = pmd_offset(pud, addr);
677         if (pmd_none(*pmd))
678                 return 0;
679         if (pmd_large(*pmd))
680                 return pfn_valid(pmd_pfn(*pmd));
681
682         pte = pte_offset_kernel(pmd, addr);
683         if (pte_none(*pte))
684                 return 0;
685         return pfn_valid(pte_pfn(*pte));
686 }
687
688 /* A pseudo VMA to allow ptrace access for the vsyscall page.  This only
689    covers the 64bit vsyscall page now. 32bit has a real VMA now and does
690    not need special handling anymore. */
691
692 static struct vm_area_struct gate_vma = {
693         .vm_start = VSYSCALL_START,
694         .vm_end = VSYSCALL_START + (VSYSCALL_MAPPED_PAGES << PAGE_SHIFT),
695         .vm_page_prot = PAGE_READONLY_EXEC,
696         .vm_flags = VM_READ | VM_EXEC
697 };
698
699 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
700 {
701 #ifdef CONFIG_IA32_EMULATION
702         if (test_tsk_thread_flag(tsk, TIF_IA32))
703                 return NULL;
704 #endif
705         return &gate_vma;
706 }
707
708 int in_gate_area(struct task_struct *task, unsigned long addr)
709 {
710         struct vm_area_struct *vma = get_gate_vma(task);
711         if (!vma)
712                 return 0;
713         return (addr >= vma->vm_start) && (addr < vma->vm_end);
714 }
715
716 /* Use this when you have no reliable task/vma, typically from interrupt
717  * context.  It is less reliable than using the task's vma and may give
718  * false positives.
719  */
720 int in_gate_area_no_task(unsigned long addr)
721 {
722         return (addr >= VSYSCALL_START) && (addr < VSYSCALL_END);
723 }
724
725 const char *arch_vma_name(struct vm_area_struct *vma)
726 {
727         if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
728                 return "[vdso]";
729         if (vma == &gate_vma)
730                 return "[vsyscall]";
731         return NULL;
732 }
733
734 #ifdef CONFIG_SPARSEMEM_VMEMMAP
735 /*
736  * Initialise the sparsemem vmemmap using huge-pages at the PMD level.
737  */
738 int __meminit vmemmap_populate(struct page *start_page,
739                                                 unsigned long size, int node)
740 {
741         unsigned long addr = (unsigned long)start_page;
742         unsigned long end = (unsigned long)(start_page + size);
743         unsigned long next;
744         pgd_t *pgd;
745         pud_t *pud;
746         pmd_t *pmd;
747
748         for (; addr < end; addr = next) {
749                 next = pmd_addr_end(addr, end);
750
751                 pgd = vmemmap_pgd_populate(addr, node);
752                 if (!pgd)
753                         return -ENOMEM;
754                 pud = vmemmap_pud_populate(pgd, addr, node);
755                 if (!pud)
756                         return -ENOMEM;
757
758                 pmd = pmd_offset(pud, addr);
759                 if (pmd_none(*pmd)) {
760                         pte_t entry;
761                         void *p = vmemmap_alloc_block(PMD_SIZE, node);
762                         if (!p)
763                                 return -ENOMEM;
764
765                         entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL_LARGE);
766                         set_pmd(pmd, __pmd(pte_val(entry)));
767
768                         printk(KERN_DEBUG " [%lx-%lx] PMD ->%p on node %d\n",
769                                 addr, addr + PMD_SIZE - 1, p, node);
770                 } else
771                         vmemmap_verify((pte_t *)pmd, node, addr, next);
772         }
773
774         return 0;
775 }
776 #endif