x86/mm: Use pte_none() to test for empty PTE
[linux] / 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@ucw.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/initrd.h>
22 #include <linux/pagemap.h>
23 #include <linux/bootmem.h>
24 #include <linux/memblock.h>
25 #include <linux/proc_fs.h>
26 #include <linux/pci.h>
27 #include <linux/pfn.h>
28 #include <linux/poison.h>
29 #include <linux/dma-mapping.h>
30 #include <linux/module.h>
31 #include <linux/memory.h>
32 #include <linux/memory_hotplug.h>
33 #include <linux/memremap.h>
34 #include <linux/nmi.h>
35 #include <linux/gfp.h>
36 #include <linux/kcore.h>
37
38 #include <asm/processor.h>
39 #include <asm/bios_ebda.h>
40 #include <asm/uaccess.h>
41 #include <asm/pgtable.h>
42 #include <asm/pgalloc.h>
43 #include <asm/dma.h>
44 #include <asm/fixmap.h>
45 #include <asm/e820.h>
46 #include <asm/apic.h>
47 #include <asm/tlb.h>
48 #include <asm/mmu_context.h>
49 #include <asm/proto.h>
50 #include <asm/smp.h>
51 #include <asm/sections.h>
52 #include <asm/kdebug.h>
53 #include <asm/numa.h>
54 #include <asm/cacheflush.h>
55 #include <asm/init.h>
56 #include <asm/uv/uv.h>
57 #include <asm/setup.h>
58
59 #include "mm_internal.h"
60
61 #include "ident_map.c"
62
63 /*
64  * NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the
65  * physical space so we can cache the place of the first one and move
66  * around without checking the pgd every time.
67  */
68
69 pteval_t __supported_pte_mask __read_mostly = ~0;
70 EXPORT_SYMBOL_GPL(__supported_pte_mask);
71
72 int force_personality32;
73
74 /*
75  * noexec32=on|off
76  * Control non executable heap for 32bit processes.
77  * To control the stack too use noexec=off
78  *
79  * on   PROT_READ does not imply PROT_EXEC for 32-bit processes (default)
80  * off  PROT_READ implies PROT_EXEC
81  */
82 static int __init nonx32_setup(char *str)
83 {
84         if (!strcmp(str, "on"))
85                 force_personality32 &= ~READ_IMPLIES_EXEC;
86         else if (!strcmp(str, "off"))
87                 force_personality32 |= READ_IMPLIES_EXEC;
88         return 1;
89 }
90 __setup("noexec32=", nonx32_setup);
91
92 /*
93  * When memory was added/removed make sure all the processes MM have
94  * suitable PGD entries in the local PGD level page.
95  */
96 void sync_global_pgds(unsigned long start, unsigned long end, int removed)
97 {
98         unsigned long address;
99
100         for (address = start; address <= end; address += PGDIR_SIZE) {
101                 const pgd_t *pgd_ref = pgd_offset_k(address);
102                 struct page *page;
103
104                 /*
105                  * When it is called after memory hot remove, pgd_none()
106                  * returns true. In this case (removed == 1), we must clear
107                  * the PGD entries in the local PGD level page.
108                  */
109                 if (pgd_none(*pgd_ref) && !removed)
110                         continue;
111
112                 spin_lock(&pgd_lock);
113                 list_for_each_entry(page, &pgd_list, lru) {
114                         pgd_t *pgd;
115                         spinlock_t *pgt_lock;
116
117                         pgd = (pgd_t *)page_address(page) + pgd_index(address);
118                         /* the pgt_lock only for Xen */
119                         pgt_lock = &pgd_page_get_mm(page)->page_table_lock;
120                         spin_lock(pgt_lock);
121
122                         if (!pgd_none(*pgd_ref) && !pgd_none(*pgd))
123                                 BUG_ON(pgd_page_vaddr(*pgd)
124                                        != pgd_page_vaddr(*pgd_ref));
125
126                         if (removed) {
127                                 if (pgd_none(*pgd_ref) && !pgd_none(*pgd))
128                                         pgd_clear(pgd);
129                         } else {
130                                 if (pgd_none(*pgd))
131                                         set_pgd(pgd, *pgd_ref);
132                         }
133
134                         spin_unlock(pgt_lock);
135                 }
136                 spin_unlock(&pgd_lock);
137         }
138 }
139
140 /*
141  * NOTE: This function is marked __ref because it calls __init function
142  * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
143  */
144 static __ref void *spp_getpage(void)
145 {
146         void *ptr;
147
148         if (after_bootmem)
149                 ptr = (void *) get_zeroed_page(GFP_ATOMIC | __GFP_NOTRACK);
150         else
151                 ptr = alloc_bootmem_pages(PAGE_SIZE);
152
153         if (!ptr || ((unsigned long)ptr & ~PAGE_MASK)) {
154                 panic("set_pte_phys: cannot allocate page data %s\n",
155                         after_bootmem ? "after bootmem" : "");
156         }
157
158         pr_debug("spp_getpage %p\n", ptr);
159
160         return ptr;
161 }
162
163 static pud_t *fill_pud(pgd_t *pgd, unsigned long vaddr)
164 {
165         if (pgd_none(*pgd)) {
166                 pud_t *pud = (pud_t *)spp_getpage();
167                 pgd_populate(&init_mm, pgd, pud);
168                 if (pud != pud_offset(pgd, 0))
169                         printk(KERN_ERR "PAGETABLE BUG #00! %p <-> %p\n",
170                                pud, pud_offset(pgd, 0));
171         }
172         return pud_offset(pgd, vaddr);
173 }
174
175 static pmd_t *fill_pmd(pud_t *pud, unsigned long vaddr)
176 {
177         if (pud_none(*pud)) {
178                 pmd_t *pmd = (pmd_t *) spp_getpage();
179                 pud_populate(&init_mm, pud, pmd);
180                 if (pmd != pmd_offset(pud, 0))
181                         printk(KERN_ERR "PAGETABLE BUG #01! %p <-> %p\n",
182                                pmd, pmd_offset(pud, 0));
183         }
184         return pmd_offset(pud, vaddr);
185 }
186
187 static pte_t *fill_pte(pmd_t *pmd, unsigned long vaddr)
188 {
189         if (pmd_none(*pmd)) {
190                 pte_t *pte = (pte_t *) spp_getpage();
191                 pmd_populate_kernel(&init_mm, pmd, pte);
192                 if (pte != pte_offset_kernel(pmd, 0))
193                         printk(KERN_ERR "PAGETABLE BUG #02!\n");
194         }
195         return pte_offset_kernel(pmd, vaddr);
196 }
197
198 void set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte)
199 {
200         pud_t *pud;
201         pmd_t *pmd;
202         pte_t *pte;
203
204         pud = pud_page + pud_index(vaddr);
205         pmd = fill_pmd(pud, vaddr);
206         pte = fill_pte(pmd, vaddr);
207
208         set_pte(pte, new_pte);
209
210         /*
211          * It's enough to flush this one mapping.
212          * (PGE mappings get flushed as well)
213          */
214         __flush_tlb_one(vaddr);
215 }
216
217 void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
218 {
219         pgd_t *pgd;
220         pud_t *pud_page;
221
222         pr_debug("set_pte_vaddr %lx to %lx\n", vaddr, native_pte_val(pteval));
223
224         pgd = pgd_offset_k(vaddr);
225         if (pgd_none(*pgd)) {
226                 printk(KERN_ERR
227                         "PGD FIXMAP MISSING, it should be setup in head.S!\n");
228                 return;
229         }
230         pud_page = (pud_t*)pgd_page_vaddr(*pgd);
231         set_pte_vaddr_pud(pud_page, vaddr, pteval);
232 }
233
234 pmd_t * __init populate_extra_pmd(unsigned long vaddr)
235 {
236         pgd_t *pgd;
237         pud_t *pud;
238
239         pgd = pgd_offset_k(vaddr);
240         pud = fill_pud(pgd, vaddr);
241         return fill_pmd(pud, vaddr);
242 }
243
244 pte_t * __init populate_extra_pte(unsigned long vaddr)
245 {
246         pmd_t *pmd;
247
248         pmd = populate_extra_pmd(vaddr);
249         return fill_pte(pmd, vaddr);
250 }
251
252 /*
253  * Create large page table mappings for a range of physical addresses.
254  */
255 static void __init __init_extra_mapping(unsigned long phys, unsigned long size,
256                                         enum page_cache_mode cache)
257 {
258         pgd_t *pgd;
259         pud_t *pud;
260         pmd_t *pmd;
261         pgprot_t prot;
262
263         pgprot_val(prot) = pgprot_val(PAGE_KERNEL_LARGE) |
264                 pgprot_val(pgprot_4k_2_large(cachemode2pgprot(cache)));
265         BUG_ON((phys & ~PMD_MASK) || (size & ~PMD_MASK));
266         for (; size; phys += PMD_SIZE, size -= PMD_SIZE) {
267                 pgd = pgd_offset_k((unsigned long)__va(phys));
268                 if (pgd_none(*pgd)) {
269                         pud = (pud_t *) spp_getpage();
270                         set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE |
271                                                 _PAGE_USER));
272                 }
273                 pud = pud_offset(pgd, (unsigned long)__va(phys));
274                 if (pud_none(*pud)) {
275                         pmd = (pmd_t *) spp_getpage();
276                         set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE |
277                                                 _PAGE_USER));
278                 }
279                 pmd = pmd_offset(pud, phys);
280                 BUG_ON(!pmd_none(*pmd));
281                 set_pmd(pmd, __pmd(phys | pgprot_val(prot)));
282         }
283 }
284
285 void __init init_extra_mapping_wb(unsigned long phys, unsigned long size)
286 {
287         __init_extra_mapping(phys, size, _PAGE_CACHE_MODE_WB);
288 }
289
290 void __init init_extra_mapping_uc(unsigned long phys, unsigned long size)
291 {
292         __init_extra_mapping(phys, size, _PAGE_CACHE_MODE_UC);
293 }
294
295 /*
296  * The head.S code sets up the kernel high mapping:
297  *
298  *   from __START_KERNEL_map to __START_KERNEL_map + size (== _end-_text)
299  *
300  * phys_base holds the negative offset to the kernel, which is added
301  * to the compile time generated pmds. This results in invalid pmds up
302  * to the point where we hit the physaddr 0 mapping.
303  *
304  * We limit the mappings to the region from _text to _brk_end.  _brk_end
305  * is rounded up to the 2MB boundary. This catches the invalid pmds as
306  * well, as they are located before _text:
307  */
308 void __init cleanup_highmap(void)
309 {
310         unsigned long vaddr = __START_KERNEL_map;
311         unsigned long vaddr_end = __START_KERNEL_map + KERNEL_IMAGE_SIZE;
312         unsigned long end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
313         pmd_t *pmd = level2_kernel_pgt;
314
315         /*
316          * Native path, max_pfn_mapped is not set yet.
317          * Xen has valid max_pfn_mapped set in
318          *      arch/x86/xen/mmu.c:xen_setup_kernel_pagetable().
319          */
320         if (max_pfn_mapped)
321                 vaddr_end = __START_KERNEL_map + (max_pfn_mapped << PAGE_SHIFT);
322
323         for (; vaddr + PMD_SIZE - 1 < vaddr_end; pmd++, vaddr += PMD_SIZE) {
324                 if (pmd_none(*pmd))
325                         continue;
326                 if (vaddr < (unsigned long) _text || vaddr > end)
327                         set_pmd(pmd, __pmd(0));
328         }
329 }
330
331 static unsigned long __meminit
332 phys_pte_init(pte_t *pte_page, unsigned long addr, unsigned long end,
333               pgprot_t prot)
334 {
335         unsigned long pages = 0, next;
336         unsigned long last_map_addr = end;
337         int i;
338
339         pte_t *pte = pte_page + pte_index(addr);
340
341         for (i = pte_index(addr); i < PTRS_PER_PTE; i++, addr = next, pte++) {
342                 next = (addr & PAGE_MASK) + PAGE_SIZE;
343                 if (addr >= end) {
344                         if (!after_bootmem &&
345                             !e820_any_mapped(addr & PAGE_MASK, next, E820_RAM) &&
346                             !e820_any_mapped(addr & PAGE_MASK, next, E820_RESERVED_KERN))
347                                 set_pte(pte, __pte(0));
348                         continue;
349                 }
350
351                 /*
352                  * We will re-use the existing mapping.
353                  * Xen for example has some special requirements, like mapping
354                  * pagetable pages as RO. So assume someone who pre-setup
355                  * these mappings are more intelligent.
356                  */
357                 if (!pte_none(*pte)) {
358                         if (!after_bootmem)
359                                 pages++;
360                         continue;
361                 }
362
363                 if (0)
364                         printk("   pte=%p addr=%lx pte=%016lx\n",
365                                pte, addr, pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL).pte);
366                 pages++;
367                 set_pte(pte, pfn_pte(addr >> PAGE_SHIFT, prot));
368                 last_map_addr = (addr & PAGE_MASK) + PAGE_SIZE;
369         }
370
371         update_page_count(PG_LEVEL_4K, pages);
372
373         return last_map_addr;
374 }
375
376 static unsigned long __meminit
377 phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
378               unsigned long page_size_mask, pgprot_t prot)
379 {
380         unsigned long pages = 0, next;
381         unsigned long last_map_addr = end;
382
383         int i = pmd_index(address);
384
385         for (; i < PTRS_PER_PMD; i++, address = next) {
386                 pmd_t *pmd = pmd_page + pmd_index(address);
387                 pte_t *pte;
388                 pgprot_t new_prot = prot;
389
390                 next = (address & PMD_MASK) + PMD_SIZE;
391                 if (address >= end) {
392                         if (!after_bootmem &&
393                             !e820_any_mapped(address & PMD_MASK, next, E820_RAM) &&
394                             !e820_any_mapped(address & PMD_MASK, next, E820_RESERVED_KERN))
395                                 set_pmd(pmd, __pmd(0));
396                         continue;
397                 }
398
399                 if (!pmd_none(*pmd)) {
400                         if (!pmd_large(*pmd)) {
401                                 spin_lock(&init_mm.page_table_lock);
402                                 pte = (pte_t *)pmd_page_vaddr(*pmd);
403                                 last_map_addr = phys_pte_init(pte, address,
404                                                                 end, prot);
405                                 spin_unlock(&init_mm.page_table_lock);
406                                 continue;
407                         }
408                         /*
409                          * If we are ok with PG_LEVEL_2M mapping, then we will
410                          * use the existing mapping,
411                          *
412                          * Otherwise, we will split the large page mapping but
413                          * use the same existing protection bits except for
414                          * large page, so that we don't violate Intel's TLB
415                          * Application note (317080) which says, while changing
416                          * the page sizes, new and old translations should
417                          * not differ with respect to page frame and
418                          * attributes.
419                          */
420                         if (page_size_mask & (1 << PG_LEVEL_2M)) {
421                                 if (!after_bootmem)
422                                         pages++;
423                                 last_map_addr = next;
424                                 continue;
425                         }
426                         new_prot = pte_pgprot(pte_clrhuge(*(pte_t *)pmd));
427                 }
428
429                 if (page_size_mask & (1<<PG_LEVEL_2M)) {
430                         pages++;
431                         spin_lock(&init_mm.page_table_lock);
432                         set_pte((pte_t *)pmd,
433                                 pfn_pte((address & PMD_MASK) >> PAGE_SHIFT,
434                                         __pgprot(pgprot_val(prot) | _PAGE_PSE)));
435                         spin_unlock(&init_mm.page_table_lock);
436                         last_map_addr = next;
437                         continue;
438                 }
439
440                 pte = alloc_low_page();
441                 last_map_addr = phys_pte_init(pte, address, end, new_prot);
442
443                 spin_lock(&init_mm.page_table_lock);
444                 pmd_populate_kernel(&init_mm, pmd, pte);
445                 spin_unlock(&init_mm.page_table_lock);
446         }
447         update_page_count(PG_LEVEL_2M, pages);
448         return last_map_addr;
449 }
450
451 static unsigned long __meminit
452 phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
453                          unsigned long page_size_mask)
454 {
455         unsigned long pages = 0, next;
456         unsigned long last_map_addr = end;
457         int i = pud_index(addr);
458
459         for (; i < PTRS_PER_PUD; i++, addr = next) {
460                 pud_t *pud = pud_page + pud_index(addr);
461                 pmd_t *pmd;
462                 pgprot_t prot = PAGE_KERNEL;
463
464                 next = (addr & PUD_MASK) + PUD_SIZE;
465                 if (addr >= end) {
466                         if (!after_bootmem &&
467                             !e820_any_mapped(addr & PUD_MASK, next, E820_RAM) &&
468                             !e820_any_mapped(addr & PUD_MASK, next, E820_RESERVED_KERN))
469                                 set_pud(pud, __pud(0));
470                         continue;
471                 }
472
473                 if (!pud_none(*pud)) {
474                         if (!pud_large(*pud)) {
475                                 pmd = pmd_offset(pud, 0);
476                                 last_map_addr = phys_pmd_init(pmd, addr, end,
477                                                          page_size_mask, prot);
478                                 __flush_tlb_all();
479                                 continue;
480                         }
481                         /*
482                          * If we are ok with PG_LEVEL_1G mapping, then we will
483                          * use the existing mapping.
484                          *
485                          * Otherwise, we will split the gbpage mapping but use
486                          * the same existing protection  bits except for large
487                          * page, so that we don't violate Intel's TLB
488                          * Application note (317080) which says, while changing
489                          * the page sizes, new and old translations should
490                          * not differ with respect to page frame and
491                          * attributes.
492                          */
493                         if (page_size_mask & (1 << PG_LEVEL_1G)) {
494                                 if (!after_bootmem)
495                                         pages++;
496                                 last_map_addr = next;
497                                 continue;
498                         }
499                         prot = pte_pgprot(pte_clrhuge(*(pte_t *)pud));
500                 }
501
502                 if (page_size_mask & (1<<PG_LEVEL_1G)) {
503                         pages++;
504                         spin_lock(&init_mm.page_table_lock);
505                         set_pte((pte_t *)pud,
506                                 pfn_pte((addr & PUD_MASK) >> PAGE_SHIFT,
507                                         PAGE_KERNEL_LARGE));
508                         spin_unlock(&init_mm.page_table_lock);
509                         last_map_addr = next;
510                         continue;
511                 }
512
513                 pmd = alloc_low_page();
514                 last_map_addr = phys_pmd_init(pmd, addr, end, page_size_mask,
515                                               prot);
516
517                 spin_lock(&init_mm.page_table_lock);
518                 pud_populate(&init_mm, pud, pmd);
519                 spin_unlock(&init_mm.page_table_lock);
520         }
521         __flush_tlb_all();
522
523         update_page_count(PG_LEVEL_1G, pages);
524
525         return last_map_addr;
526 }
527
528 unsigned long __meminit
529 kernel_physical_mapping_init(unsigned long start,
530                              unsigned long end,
531                              unsigned long page_size_mask)
532 {
533         bool pgd_changed = false;
534         unsigned long next, last_map_addr = end;
535         unsigned long addr;
536
537         start = (unsigned long)__va(start);
538         end = (unsigned long)__va(end);
539         addr = start;
540
541         for (; start < end; start = next) {
542                 pgd_t *pgd = pgd_offset_k(start);
543                 pud_t *pud;
544
545                 next = (start & PGDIR_MASK) + PGDIR_SIZE;
546
547                 if (pgd_val(*pgd)) {
548                         pud = (pud_t *)pgd_page_vaddr(*pgd);
549                         last_map_addr = phys_pud_init(pud, __pa(start),
550                                                  __pa(end), page_size_mask);
551                         continue;
552                 }
553
554                 pud = alloc_low_page();
555                 last_map_addr = phys_pud_init(pud, __pa(start), __pa(end),
556                                                  page_size_mask);
557
558                 spin_lock(&init_mm.page_table_lock);
559                 pgd_populate(&init_mm, pgd, pud);
560                 spin_unlock(&init_mm.page_table_lock);
561                 pgd_changed = true;
562         }
563
564         if (pgd_changed)
565                 sync_global_pgds(addr, end - 1, 0);
566
567         __flush_tlb_all();
568
569         return last_map_addr;
570 }
571
572 #ifndef CONFIG_NUMA
573 void __init initmem_init(void)
574 {
575         memblock_set_node(0, (phys_addr_t)ULLONG_MAX, &memblock.memory, 0);
576 }
577 #endif
578
579 void __init paging_init(void)
580 {
581         sparse_memory_present_with_active_regions(MAX_NUMNODES);
582         sparse_init();
583
584         /*
585          * clear the default setting with node 0
586          * note: don't use nodes_clear here, that is really clearing when
587          *       numa support is not compiled in, and later node_set_state
588          *       will not set it back.
589          */
590         node_clear_state(0, N_MEMORY);
591         if (N_MEMORY != N_NORMAL_MEMORY)
592                 node_clear_state(0, N_NORMAL_MEMORY);
593
594         zone_sizes_init();
595 }
596
597 /*
598  * Memory hotplug specific functions
599  */
600 #ifdef CONFIG_MEMORY_HOTPLUG
601 /*
602  * After memory hotplug the variables max_pfn, max_low_pfn and high_memory need
603  * updating.
604  */
605 static void  update_end_of_memory_vars(u64 start, u64 size)
606 {
607         unsigned long end_pfn = PFN_UP(start + size);
608
609         if (end_pfn > max_pfn) {
610                 max_pfn = end_pfn;
611                 max_low_pfn = end_pfn;
612                 high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
613         }
614 }
615
616 /*
617  * Memory is added always to NORMAL zone. This means you will never get
618  * additional DMA/DMA32 memory.
619  */
620 int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
621 {
622         struct pglist_data *pgdat = NODE_DATA(nid);
623         struct zone *zone = pgdat->node_zones +
624                 zone_for_memory(nid, start, size, ZONE_NORMAL, for_device);
625         unsigned long start_pfn = start >> PAGE_SHIFT;
626         unsigned long nr_pages = size >> PAGE_SHIFT;
627         int ret;
628
629         init_memory_mapping(start, start + size);
630
631         ret = __add_pages(nid, zone, start_pfn, nr_pages);
632         WARN_ON_ONCE(ret);
633
634         /* update max_pfn, max_low_pfn and high_memory */
635         update_end_of_memory_vars(start, size);
636
637         return ret;
638 }
639 EXPORT_SYMBOL_GPL(arch_add_memory);
640
641 #define PAGE_INUSE 0xFD
642
643 static void __meminit free_pagetable(struct page *page, int order)
644 {
645         unsigned long magic;
646         unsigned int nr_pages = 1 << order;
647         struct vmem_altmap *altmap = to_vmem_altmap((unsigned long) page);
648
649         if (altmap) {
650                 vmem_altmap_free(altmap, nr_pages);
651                 return;
652         }
653
654         /* bootmem page has reserved flag */
655         if (PageReserved(page)) {
656                 __ClearPageReserved(page);
657
658                 magic = (unsigned long)page->lru.next;
659                 if (magic == SECTION_INFO || magic == MIX_SECTION_INFO) {
660                         while (nr_pages--)
661                                 put_page_bootmem(page++);
662                 } else
663                         while (nr_pages--)
664                                 free_reserved_page(page++);
665         } else
666                 free_pages((unsigned long)page_address(page), order);
667 }
668
669 static void __meminit free_pte_table(pte_t *pte_start, pmd_t *pmd)
670 {
671         pte_t *pte;
672         int i;
673
674         for (i = 0; i < PTRS_PER_PTE; i++) {
675                 pte = pte_start + i;
676                 if (!pte_none(*pte))
677                         return;
678         }
679
680         /* free a pte talbe */
681         free_pagetable(pmd_page(*pmd), 0);
682         spin_lock(&init_mm.page_table_lock);
683         pmd_clear(pmd);
684         spin_unlock(&init_mm.page_table_lock);
685 }
686
687 static void __meminit free_pmd_table(pmd_t *pmd_start, pud_t *pud)
688 {
689         pmd_t *pmd;
690         int i;
691
692         for (i = 0; i < PTRS_PER_PMD; i++) {
693                 pmd = pmd_start + i;
694                 if (!pmd_none(*pmd))
695                         return;
696         }
697
698         /* free a pmd talbe */
699         free_pagetable(pud_page(*pud), 0);
700         spin_lock(&init_mm.page_table_lock);
701         pud_clear(pud);
702         spin_unlock(&init_mm.page_table_lock);
703 }
704
705 /* Return true if pgd is changed, otherwise return false. */
706 static bool __meminit free_pud_table(pud_t *pud_start, pgd_t *pgd)
707 {
708         pud_t *pud;
709         int i;
710
711         for (i = 0; i < PTRS_PER_PUD; i++) {
712                 pud = pud_start + i;
713                 if (!pud_none(*pud))
714                         return false;
715         }
716
717         /* free a pud table */
718         free_pagetable(pgd_page(*pgd), 0);
719         spin_lock(&init_mm.page_table_lock);
720         pgd_clear(pgd);
721         spin_unlock(&init_mm.page_table_lock);
722
723         return true;
724 }
725
726 static void __meminit
727 remove_pte_table(pte_t *pte_start, unsigned long addr, unsigned long end,
728                  bool direct)
729 {
730         unsigned long next, pages = 0;
731         pte_t *pte;
732         void *page_addr;
733         phys_addr_t phys_addr;
734
735         pte = pte_start + pte_index(addr);
736         for (; addr < end; addr = next, pte++) {
737                 next = (addr + PAGE_SIZE) & PAGE_MASK;
738                 if (next > end)
739                         next = end;
740
741                 if (!pte_present(*pte))
742                         continue;
743
744                 /*
745                  * We mapped [0,1G) memory as identity mapping when
746                  * initializing, in arch/x86/kernel/head_64.S. These
747                  * pagetables cannot be removed.
748                  */
749                 phys_addr = pte_val(*pte) + (addr & PAGE_MASK);
750                 if (phys_addr < (phys_addr_t)0x40000000)
751                         return;
752
753                 if (PAGE_ALIGNED(addr) && PAGE_ALIGNED(next)) {
754                         /*
755                          * Do not free direct mapping pages since they were
756                          * freed when offlining, or simplely not in use.
757                          */
758                         if (!direct)
759                                 free_pagetable(pte_page(*pte), 0);
760
761                         spin_lock(&init_mm.page_table_lock);
762                         pte_clear(&init_mm, addr, pte);
763                         spin_unlock(&init_mm.page_table_lock);
764
765                         /* For non-direct mapping, pages means nothing. */
766                         pages++;
767                 } else {
768                         /*
769                          * If we are here, we are freeing vmemmap pages since
770                          * direct mapped memory ranges to be freed are aligned.
771                          *
772                          * If we are not removing the whole page, it means
773                          * other page structs in this page are being used and
774                          * we canot remove them. So fill the unused page_structs
775                          * with 0xFD, and remove the page when it is wholly
776                          * filled with 0xFD.
777                          */
778                         memset((void *)addr, PAGE_INUSE, next - addr);
779
780                         page_addr = page_address(pte_page(*pte));
781                         if (!memchr_inv(page_addr, PAGE_INUSE, PAGE_SIZE)) {
782                                 free_pagetable(pte_page(*pte), 0);
783
784                                 spin_lock(&init_mm.page_table_lock);
785                                 pte_clear(&init_mm, addr, pte);
786                                 spin_unlock(&init_mm.page_table_lock);
787                         }
788                 }
789         }
790
791         /* Call free_pte_table() in remove_pmd_table(). */
792         flush_tlb_all();
793         if (direct)
794                 update_page_count(PG_LEVEL_4K, -pages);
795 }
796
797 static void __meminit
798 remove_pmd_table(pmd_t *pmd_start, unsigned long addr, unsigned long end,
799                  bool direct)
800 {
801         unsigned long next, pages = 0;
802         pte_t *pte_base;
803         pmd_t *pmd;
804         void *page_addr;
805
806         pmd = pmd_start + pmd_index(addr);
807         for (; addr < end; addr = next, pmd++) {
808                 next = pmd_addr_end(addr, end);
809
810                 if (!pmd_present(*pmd))
811                         continue;
812
813                 if (pmd_large(*pmd)) {
814                         if (IS_ALIGNED(addr, PMD_SIZE) &&
815                             IS_ALIGNED(next, PMD_SIZE)) {
816                                 if (!direct)
817                                         free_pagetable(pmd_page(*pmd),
818                                                        get_order(PMD_SIZE));
819
820                                 spin_lock(&init_mm.page_table_lock);
821                                 pmd_clear(pmd);
822                                 spin_unlock(&init_mm.page_table_lock);
823                                 pages++;
824                         } else {
825                                 /* If here, we are freeing vmemmap pages. */
826                                 memset((void *)addr, PAGE_INUSE, next - addr);
827
828                                 page_addr = page_address(pmd_page(*pmd));
829                                 if (!memchr_inv(page_addr, PAGE_INUSE,
830                                                 PMD_SIZE)) {
831                                         free_pagetable(pmd_page(*pmd),
832                                                        get_order(PMD_SIZE));
833
834                                         spin_lock(&init_mm.page_table_lock);
835                                         pmd_clear(pmd);
836                                         spin_unlock(&init_mm.page_table_lock);
837                                 }
838                         }
839
840                         continue;
841                 }
842
843                 pte_base = (pte_t *)pmd_page_vaddr(*pmd);
844                 remove_pte_table(pte_base, addr, next, direct);
845                 free_pte_table(pte_base, pmd);
846         }
847
848         /* Call free_pmd_table() in remove_pud_table(). */
849         if (direct)
850                 update_page_count(PG_LEVEL_2M, -pages);
851 }
852
853 static void __meminit
854 remove_pud_table(pud_t *pud_start, unsigned long addr, unsigned long end,
855                  bool direct)
856 {
857         unsigned long next, pages = 0;
858         pmd_t *pmd_base;
859         pud_t *pud;
860         void *page_addr;
861
862         pud = pud_start + pud_index(addr);
863         for (; addr < end; addr = next, pud++) {
864                 next = pud_addr_end(addr, end);
865
866                 if (!pud_present(*pud))
867                         continue;
868
869                 if (pud_large(*pud)) {
870                         if (IS_ALIGNED(addr, PUD_SIZE) &&
871                             IS_ALIGNED(next, PUD_SIZE)) {
872                                 if (!direct)
873                                         free_pagetable(pud_page(*pud),
874                                                        get_order(PUD_SIZE));
875
876                                 spin_lock(&init_mm.page_table_lock);
877                                 pud_clear(pud);
878                                 spin_unlock(&init_mm.page_table_lock);
879                                 pages++;
880                         } else {
881                                 /* If here, we are freeing vmemmap pages. */
882                                 memset((void *)addr, PAGE_INUSE, next - addr);
883
884                                 page_addr = page_address(pud_page(*pud));
885                                 if (!memchr_inv(page_addr, PAGE_INUSE,
886                                                 PUD_SIZE)) {
887                                         free_pagetable(pud_page(*pud),
888                                                        get_order(PUD_SIZE));
889
890                                         spin_lock(&init_mm.page_table_lock);
891                                         pud_clear(pud);
892                                         spin_unlock(&init_mm.page_table_lock);
893                                 }
894                         }
895
896                         continue;
897                 }
898
899                 pmd_base = (pmd_t *)pud_page_vaddr(*pud);
900                 remove_pmd_table(pmd_base, addr, next, direct);
901                 free_pmd_table(pmd_base, pud);
902         }
903
904         if (direct)
905                 update_page_count(PG_LEVEL_1G, -pages);
906 }
907
908 /* start and end are both virtual address. */
909 static void __meminit
910 remove_pagetable(unsigned long start, unsigned long end, bool direct)
911 {
912         unsigned long next;
913         unsigned long addr;
914         pgd_t *pgd;
915         pud_t *pud;
916         bool pgd_changed = false;
917
918         for (addr = start; addr < end; addr = next) {
919                 next = pgd_addr_end(addr, end);
920
921                 pgd = pgd_offset_k(addr);
922                 if (!pgd_present(*pgd))
923                         continue;
924
925                 pud = (pud_t *)pgd_page_vaddr(*pgd);
926                 remove_pud_table(pud, addr, next, direct);
927                 if (free_pud_table(pud, pgd))
928                         pgd_changed = true;
929         }
930
931         if (pgd_changed)
932                 sync_global_pgds(start, end - 1, 1);
933
934         flush_tlb_all();
935 }
936
937 void __ref vmemmap_free(unsigned long start, unsigned long end)
938 {
939         remove_pagetable(start, end, false);
940 }
941
942 #ifdef CONFIG_MEMORY_HOTREMOVE
943 static void __meminit
944 kernel_physical_mapping_remove(unsigned long start, unsigned long end)
945 {
946         start = (unsigned long)__va(start);
947         end = (unsigned long)__va(end);
948
949         remove_pagetable(start, end, true);
950 }
951
952 int __ref arch_remove_memory(u64 start, u64 size)
953 {
954         unsigned long start_pfn = start >> PAGE_SHIFT;
955         unsigned long nr_pages = size >> PAGE_SHIFT;
956         struct page *page = pfn_to_page(start_pfn);
957         struct vmem_altmap *altmap;
958         struct zone *zone;
959         int ret;
960
961         /* With altmap the first mapped page is offset from @start */
962         altmap = to_vmem_altmap((unsigned long) page);
963         if (altmap)
964                 page += vmem_altmap_offset(altmap);
965         zone = page_zone(page);
966         ret = __remove_pages(zone, start_pfn, nr_pages);
967         WARN_ON_ONCE(ret);
968         kernel_physical_mapping_remove(start, start + size);
969
970         return ret;
971 }
972 #endif
973 #endif /* CONFIG_MEMORY_HOTPLUG */
974
975 static struct kcore_list kcore_vsyscall;
976
977 static void __init register_page_bootmem_info(void)
978 {
979 #ifdef CONFIG_NUMA
980         int i;
981
982         for_each_online_node(i)
983                 register_page_bootmem_info_node(NODE_DATA(i));
984 #endif
985 }
986
987 void __init mem_init(void)
988 {
989         pci_iommu_alloc();
990
991         /* clear_bss() already clear the empty_zero_page */
992
993         register_page_bootmem_info();
994
995         /* this will put all memory onto the freelists */
996         free_all_bootmem();
997         after_bootmem = 1;
998
999         /* Register memory areas for /proc/kcore */
1000         kclist_add(&kcore_vsyscall, (void *)VSYSCALL_ADDR,
1001                          PAGE_SIZE, KCORE_OTHER);
1002
1003         mem_init_print_info(NULL);
1004 }
1005
1006 const int rodata_test_data = 0xC3;
1007 EXPORT_SYMBOL_GPL(rodata_test_data);
1008
1009 int kernel_set_to_readonly;
1010
1011 void set_kernel_text_rw(void)
1012 {
1013         unsigned long start = PFN_ALIGN(_text);
1014         unsigned long end = PFN_ALIGN(__stop___ex_table);
1015
1016         if (!kernel_set_to_readonly)
1017                 return;
1018
1019         pr_debug("Set kernel text: %lx - %lx for read write\n",
1020                  start, end);
1021
1022         /*
1023          * Make the kernel identity mapping for text RW. Kernel text
1024          * mapping will always be RO. Refer to the comment in
1025          * static_protections() in pageattr.c
1026          */
1027         set_memory_rw(start, (end - start) >> PAGE_SHIFT);
1028 }
1029
1030 void set_kernel_text_ro(void)
1031 {
1032         unsigned long start = PFN_ALIGN(_text);
1033         unsigned long end = PFN_ALIGN(__stop___ex_table);
1034
1035         if (!kernel_set_to_readonly)
1036                 return;
1037
1038         pr_debug("Set kernel text: %lx - %lx for read only\n",
1039                  start, end);
1040
1041         /*
1042          * Set the kernel identity mapping for text RO.
1043          */
1044         set_memory_ro(start, (end - start) >> PAGE_SHIFT);
1045 }
1046
1047 void mark_rodata_ro(void)
1048 {
1049         unsigned long start = PFN_ALIGN(_text);
1050         unsigned long rodata_start = PFN_ALIGN(__start_rodata);
1051         unsigned long end = (unsigned long) &__end_rodata_hpage_align;
1052         unsigned long text_end = PFN_ALIGN(&__stop___ex_table);
1053         unsigned long rodata_end = PFN_ALIGN(&__end_rodata);
1054         unsigned long all_end;
1055
1056         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1057                (end - start) >> 10);
1058         set_memory_ro(start, (end - start) >> PAGE_SHIFT);
1059
1060         kernel_set_to_readonly = 1;
1061
1062         /*
1063          * The rodata/data/bss/brk section (but not the kernel text!)
1064          * should also be not-executable.
1065          *
1066          * We align all_end to PMD_SIZE because the existing mapping
1067          * is a full PMD. If we would align _brk_end to PAGE_SIZE we
1068          * split the PMD and the reminder between _brk_end and the end
1069          * of the PMD will remain mapped executable.
1070          *
1071          * Any PMD which was setup after the one which covers _brk_end
1072          * has been zapped already via cleanup_highmem().
1073          */
1074         all_end = roundup((unsigned long)_brk_end, PMD_SIZE);
1075         set_memory_nx(text_end, (all_end - text_end) >> PAGE_SHIFT);
1076
1077         rodata_test();
1078
1079 #ifdef CONFIG_CPA_DEBUG
1080         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, end);
1081         set_memory_rw(start, (end-start) >> PAGE_SHIFT);
1082
1083         printk(KERN_INFO "Testing CPA: again\n");
1084         set_memory_ro(start, (end-start) >> PAGE_SHIFT);
1085 #endif
1086
1087         free_init_pages("unused kernel",
1088                         (unsigned long) __va(__pa_symbol(text_end)),
1089                         (unsigned long) __va(__pa_symbol(rodata_start)));
1090         free_init_pages("unused kernel",
1091                         (unsigned long) __va(__pa_symbol(rodata_end)),
1092                         (unsigned long) __va(__pa_symbol(_sdata)));
1093
1094         debug_checkwx();
1095 }
1096
1097 int kern_addr_valid(unsigned long addr)
1098 {
1099         unsigned long above = ((long)addr) >> __VIRTUAL_MASK_SHIFT;
1100         pgd_t *pgd;
1101         pud_t *pud;
1102         pmd_t *pmd;
1103         pte_t *pte;
1104
1105         if (above != 0 && above != -1UL)
1106                 return 0;
1107
1108         pgd = pgd_offset_k(addr);
1109         if (pgd_none(*pgd))
1110                 return 0;
1111
1112         pud = pud_offset(pgd, addr);
1113         if (pud_none(*pud))
1114                 return 0;
1115
1116         if (pud_large(*pud))
1117                 return pfn_valid(pud_pfn(*pud));
1118
1119         pmd = pmd_offset(pud, addr);
1120         if (pmd_none(*pmd))
1121                 return 0;
1122
1123         if (pmd_large(*pmd))
1124                 return pfn_valid(pmd_pfn(*pmd));
1125
1126         pte = pte_offset_kernel(pmd, addr);
1127         if (pte_none(*pte))
1128                 return 0;
1129
1130         return pfn_valid(pte_pfn(*pte));
1131 }
1132
1133 static unsigned long probe_memory_block_size(void)
1134 {
1135         unsigned long bz = MIN_MEMORY_BLOCK_SIZE;
1136
1137         /* if system is UV or has 64GB of RAM or more, use large blocks */
1138         if (is_uv_system() || ((max_pfn << PAGE_SHIFT) >= (64UL << 30)))
1139                 bz = 2UL << 30; /* 2GB */
1140
1141         pr_info("x86/mm: Memory block size: %ldMB\n", bz >> 20);
1142
1143         return bz;
1144 }
1145
1146 static unsigned long memory_block_size_probed;
1147 unsigned long memory_block_size_bytes(void)
1148 {
1149         if (!memory_block_size_probed)
1150                 memory_block_size_probed = probe_memory_block_size();
1151
1152         return memory_block_size_probed;
1153 }
1154
1155 #ifdef CONFIG_SPARSEMEM_VMEMMAP
1156 /*
1157  * Initialise the sparsemem vmemmap using huge-pages at the PMD level.
1158  */
1159 static long __meminitdata addr_start, addr_end;
1160 static void __meminitdata *p_start, *p_end;
1161 static int __meminitdata node_start;
1162
1163 static int __meminit vmemmap_populate_hugepages(unsigned long start,
1164                 unsigned long end, int node, struct vmem_altmap *altmap)
1165 {
1166         unsigned long addr;
1167         unsigned long next;
1168         pgd_t *pgd;
1169         pud_t *pud;
1170         pmd_t *pmd;
1171
1172         for (addr = start; addr < end; addr = next) {
1173                 next = pmd_addr_end(addr, end);
1174
1175                 pgd = vmemmap_pgd_populate(addr, node);
1176                 if (!pgd)
1177                         return -ENOMEM;
1178
1179                 pud = vmemmap_pud_populate(pgd, addr, node);
1180                 if (!pud)
1181                         return -ENOMEM;
1182
1183                 pmd = pmd_offset(pud, addr);
1184                 if (pmd_none(*pmd)) {
1185                         void *p;
1186
1187                         p = __vmemmap_alloc_block_buf(PMD_SIZE, node, altmap);
1188                         if (p) {
1189                                 pte_t entry;
1190
1191                                 entry = pfn_pte(__pa(p) >> PAGE_SHIFT,
1192                                                 PAGE_KERNEL_LARGE);
1193                                 set_pmd(pmd, __pmd(pte_val(entry)));
1194
1195                                 /* check to see if we have contiguous blocks */
1196                                 if (p_end != p || node_start != node) {
1197                                         if (p_start)
1198                                                 pr_debug(" [%lx-%lx] PMD -> [%p-%p] on node %d\n",
1199                                                        addr_start, addr_end-1, p_start, p_end-1, node_start);
1200                                         addr_start = addr;
1201                                         node_start = node;
1202                                         p_start = p;
1203                                 }
1204
1205                                 addr_end = addr + PMD_SIZE;
1206                                 p_end = p + PMD_SIZE;
1207                                 continue;
1208                         } else if (altmap)
1209                                 return -ENOMEM; /* no fallback */
1210                 } else if (pmd_large(*pmd)) {
1211                         vmemmap_verify((pte_t *)pmd, node, addr, next);
1212                         continue;
1213                 }
1214                 pr_warn_once("vmemmap: falling back to regular page backing\n");
1215                 if (vmemmap_populate_basepages(addr, next, node))
1216                         return -ENOMEM;
1217         }
1218         return 0;
1219 }
1220
1221 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
1222 {
1223         struct vmem_altmap *altmap = to_vmem_altmap(start);
1224         int err;
1225
1226         if (boot_cpu_has(X86_FEATURE_PSE))
1227                 err = vmemmap_populate_hugepages(start, end, node, altmap);
1228         else if (altmap) {
1229                 pr_err_once("%s: no cpu support for altmap allocations\n",
1230                                 __func__);
1231                 err = -ENOMEM;
1232         } else
1233                 err = vmemmap_populate_basepages(start, end, node);
1234         if (!err)
1235                 sync_global_pgds(start, end - 1, 0);
1236         return err;
1237 }
1238
1239 #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HAVE_BOOTMEM_INFO_NODE)
1240 void register_page_bootmem_memmap(unsigned long section_nr,
1241                                   struct page *start_page, unsigned long size)
1242 {
1243         unsigned long addr = (unsigned long)start_page;
1244         unsigned long end = (unsigned long)(start_page + size);
1245         unsigned long next;
1246         pgd_t *pgd;
1247         pud_t *pud;
1248         pmd_t *pmd;
1249         unsigned int nr_pages;
1250         struct page *page;
1251
1252         for (; addr < end; addr = next) {
1253                 pte_t *pte = NULL;
1254
1255                 pgd = pgd_offset_k(addr);
1256                 if (pgd_none(*pgd)) {
1257                         next = (addr + PAGE_SIZE) & PAGE_MASK;
1258                         continue;
1259                 }
1260                 get_page_bootmem(section_nr, pgd_page(*pgd), MIX_SECTION_INFO);
1261
1262                 pud = pud_offset(pgd, addr);
1263                 if (pud_none(*pud)) {
1264                         next = (addr + PAGE_SIZE) & PAGE_MASK;
1265                         continue;
1266                 }
1267                 get_page_bootmem(section_nr, pud_page(*pud), MIX_SECTION_INFO);
1268
1269                 if (!boot_cpu_has(X86_FEATURE_PSE)) {
1270                         next = (addr + PAGE_SIZE) & PAGE_MASK;
1271                         pmd = pmd_offset(pud, addr);
1272                         if (pmd_none(*pmd))
1273                                 continue;
1274                         get_page_bootmem(section_nr, pmd_page(*pmd),
1275                                          MIX_SECTION_INFO);
1276
1277                         pte = pte_offset_kernel(pmd, addr);
1278                         if (pte_none(*pte))
1279                                 continue;
1280                         get_page_bootmem(section_nr, pte_page(*pte),
1281                                          SECTION_INFO);
1282                 } else {
1283                         next = pmd_addr_end(addr, end);
1284
1285                         pmd = pmd_offset(pud, addr);
1286                         if (pmd_none(*pmd))
1287                                 continue;
1288
1289                         nr_pages = 1 << (get_order(PMD_SIZE));
1290                         page = pmd_page(*pmd);
1291                         while (nr_pages--)
1292                                 get_page_bootmem(section_nr, page++,
1293                                                  SECTION_INFO);
1294                 }
1295         }
1296 }
1297 #endif
1298
1299 void __meminit vmemmap_populate_print_last(void)
1300 {
1301         if (p_start) {
1302                 pr_debug(" [%lx-%lx] PMD -> [%p-%p] on node %d\n",
1303                         addr_start, addr_end-1, p_start, p_end-1, node_start);
1304                 p_start = NULL;
1305                 p_end = NULL;
1306                 node_start = 0;
1307         }
1308 }
1309 #endif