xref: /linux/arch/x86/mm/init_64.c (revision 402cb8dda949d9b8c0df20ad2527d139faad7ca1)
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/memory.h>
31 #include <linux/memory_hotplug.h>
32 #include <linux/memremap.h>
33 #include <linux/nmi.h>
34 #include <linux/gfp.h>
35 #include <linux/kcore.h>
36 
37 #include <asm/processor.h>
38 #include <asm/bios_ebda.h>
39 #include <linux/uaccess.h>
40 #include <asm/pgtable.h>
41 #include <asm/pgalloc.h>
42 #include <asm/dma.h>
43 #include <asm/fixmap.h>
44 #include <asm/e820/api.h>
45 #include <asm/apic.h>
46 #include <asm/tlb.h>
47 #include <asm/mmu_context.h>
48 #include <asm/proto.h>
49 #include <asm/smp.h>
50 #include <asm/sections.h>
51 #include <asm/kdebug.h>
52 #include <asm/numa.h>
53 #include <asm/set_memory.h>
54 #include <asm/init.h>
55 #include <asm/uv/uv.h>
56 #include <asm/setup.h>
57 
58 #include "mm_internal.h"
59 
60 #include "ident_map.c"
61 
62 /*
63  * NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the
64  * physical space so we can cache the place of the first one and move
65  * around without checking the pgd every time.
66  */
67 
68 pteval_t __supported_pte_mask __read_mostly = ~0;
69 EXPORT_SYMBOL_GPL(__supported_pte_mask);
70 
71 int force_personality32;
72 
73 /*
74  * noexec32=on|off
75  * Control non executable heap for 32bit processes.
76  * To control the stack too use noexec=off
77  *
78  * on	PROT_READ does not imply PROT_EXEC for 32-bit processes (default)
79  * off	PROT_READ implies PROT_EXEC
80  */
81 static int __init nonx32_setup(char *str)
82 {
83 	if (!strcmp(str, "on"))
84 		force_personality32 &= ~READ_IMPLIES_EXEC;
85 	else if (!strcmp(str, "off"))
86 		force_personality32 |= READ_IMPLIES_EXEC;
87 	return 1;
88 }
89 __setup("noexec32=", nonx32_setup);
90 
91 static void sync_global_pgds_l5(unsigned long start, unsigned long end)
92 {
93 	unsigned long addr;
94 
95 	for (addr = start; addr <= end; addr = ALIGN(addr + 1, PGDIR_SIZE)) {
96 		const pgd_t *pgd_ref = pgd_offset_k(addr);
97 		struct page *page;
98 
99 		/* Check for overflow */
100 		if (addr < start)
101 			break;
102 
103 		if (pgd_none(*pgd_ref))
104 			continue;
105 
106 		spin_lock(&pgd_lock);
107 		list_for_each_entry(page, &pgd_list, lru) {
108 			pgd_t *pgd;
109 			spinlock_t *pgt_lock;
110 
111 			pgd = (pgd_t *)page_address(page) + pgd_index(addr);
112 			/* the pgt_lock only for Xen */
113 			pgt_lock = &pgd_page_get_mm(page)->page_table_lock;
114 			spin_lock(pgt_lock);
115 
116 			if (!pgd_none(*pgd_ref) && !pgd_none(*pgd))
117 				BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
118 
119 			if (pgd_none(*pgd))
120 				set_pgd(pgd, *pgd_ref);
121 
122 			spin_unlock(pgt_lock);
123 		}
124 		spin_unlock(&pgd_lock);
125 	}
126 }
127 
128 static void sync_global_pgds_l4(unsigned long start, unsigned long end)
129 {
130 	unsigned long addr;
131 
132 	for (addr = start; addr <= end; addr = ALIGN(addr + 1, PGDIR_SIZE)) {
133 		pgd_t *pgd_ref = pgd_offset_k(addr);
134 		const p4d_t *p4d_ref;
135 		struct page *page;
136 
137 		/*
138 		 * With folded p4d, pgd_none() is always false, we need to
139 		 * handle synchonization on p4d level.
140 		 */
141 		MAYBE_BUILD_BUG_ON(pgd_none(*pgd_ref));
142 		p4d_ref = p4d_offset(pgd_ref, addr);
143 
144 		if (p4d_none(*p4d_ref))
145 			continue;
146 
147 		spin_lock(&pgd_lock);
148 		list_for_each_entry(page, &pgd_list, lru) {
149 			pgd_t *pgd;
150 			p4d_t *p4d;
151 			spinlock_t *pgt_lock;
152 
153 			pgd = (pgd_t *)page_address(page) + pgd_index(addr);
154 			p4d = p4d_offset(pgd, addr);
155 			/* the pgt_lock only for Xen */
156 			pgt_lock = &pgd_page_get_mm(page)->page_table_lock;
157 			spin_lock(pgt_lock);
158 
159 			if (!p4d_none(*p4d_ref) && !p4d_none(*p4d))
160 				BUG_ON(p4d_page_vaddr(*p4d)
161 				       != p4d_page_vaddr(*p4d_ref));
162 
163 			if (p4d_none(*p4d))
164 				set_p4d(p4d, *p4d_ref);
165 
166 			spin_unlock(pgt_lock);
167 		}
168 		spin_unlock(&pgd_lock);
169 	}
170 }
171 
172 /*
173  * When memory was added make sure all the processes MM have
174  * suitable PGD entries in the local PGD level page.
175  */
176 void sync_global_pgds(unsigned long start, unsigned long end)
177 {
178 	if (pgtable_l5_enabled)
179 		sync_global_pgds_l5(start, end);
180 	else
181 		sync_global_pgds_l4(start, end);
182 }
183 
184 /*
185  * NOTE: This function is marked __ref because it calls __init function
186  * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
187  */
188 static __ref void *spp_getpage(void)
189 {
190 	void *ptr;
191 
192 	if (after_bootmem)
193 		ptr = (void *) get_zeroed_page(GFP_ATOMIC);
194 	else
195 		ptr = alloc_bootmem_pages(PAGE_SIZE);
196 
197 	if (!ptr || ((unsigned long)ptr & ~PAGE_MASK)) {
198 		panic("set_pte_phys: cannot allocate page data %s\n",
199 			after_bootmem ? "after bootmem" : "");
200 	}
201 
202 	pr_debug("spp_getpage %p\n", ptr);
203 
204 	return ptr;
205 }
206 
207 static p4d_t *fill_p4d(pgd_t *pgd, unsigned long vaddr)
208 {
209 	if (pgd_none(*pgd)) {
210 		p4d_t *p4d = (p4d_t *)spp_getpage();
211 		pgd_populate(&init_mm, pgd, p4d);
212 		if (p4d != p4d_offset(pgd, 0))
213 			printk(KERN_ERR "PAGETABLE BUG #00! %p <-> %p\n",
214 			       p4d, p4d_offset(pgd, 0));
215 	}
216 	return p4d_offset(pgd, vaddr);
217 }
218 
219 static pud_t *fill_pud(p4d_t *p4d, unsigned long vaddr)
220 {
221 	if (p4d_none(*p4d)) {
222 		pud_t *pud = (pud_t *)spp_getpage();
223 		p4d_populate(&init_mm, p4d, pud);
224 		if (pud != pud_offset(p4d, 0))
225 			printk(KERN_ERR "PAGETABLE BUG #01! %p <-> %p\n",
226 			       pud, pud_offset(p4d, 0));
227 	}
228 	return pud_offset(p4d, vaddr);
229 }
230 
231 static pmd_t *fill_pmd(pud_t *pud, unsigned long vaddr)
232 {
233 	if (pud_none(*pud)) {
234 		pmd_t *pmd = (pmd_t *) spp_getpage();
235 		pud_populate(&init_mm, pud, pmd);
236 		if (pmd != pmd_offset(pud, 0))
237 			printk(KERN_ERR "PAGETABLE BUG #02! %p <-> %p\n",
238 			       pmd, pmd_offset(pud, 0));
239 	}
240 	return pmd_offset(pud, vaddr);
241 }
242 
243 static pte_t *fill_pte(pmd_t *pmd, unsigned long vaddr)
244 {
245 	if (pmd_none(*pmd)) {
246 		pte_t *pte = (pte_t *) spp_getpage();
247 		pmd_populate_kernel(&init_mm, pmd, pte);
248 		if (pte != pte_offset_kernel(pmd, 0))
249 			printk(KERN_ERR "PAGETABLE BUG #03!\n");
250 	}
251 	return pte_offset_kernel(pmd, vaddr);
252 }
253 
254 static void __set_pte_vaddr(pud_t *pud, unsigned long vaddr, pte_t new_pte)
255 {
256 	pmd_t *pmd = fill_pmd(pud, vaddr);
257 	pte_t *pte = fill_pte(pmd, vaddr);
258 
259 	set_pte(pte, new_pte);
260 
261 	/*
262 	 * It's enough to flush this one mapping.
263 	 * (PGE mappings get flushed as well)
264 	 */
265 	__flush_tlb_one_kernel(vaddr);
266 }
267 
268 void set_pte_vaddr_p4d(p4d_t *p4d_page, unsigned long vaddr, pte_t new_pte)
269 {
270 	p4d_t *p4d = p4d_page + p4d_index(vaddr);
271 	pud_t *pud = fill_pud(p4d, vaddr);
272 
273 	__set_pte_vaddr(pud, vaddr, new_pte);
274 }
275 
276 void set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte)
277 {
278 	pud_t *pud = pud_page + pud_index(vaddr);
279 
280 	__set_pte_vaddr(pud, vaddr, new_pte);
281 }
282 
283 void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
284 {
285 	pgd_t *pgd;
286 	p4d_t *p4d_page;
287 
288 	pr_debug("set_pte_vaddr %lx to %lx\n", vaddr, native_pte_val(pteval));
289 
290 	pgd = pgd_offset_k(vaddr);
291 	if (pgd_none(*pgd)) {
292 		printk(KERN_ERR
293 			"PGD FIXMAP MISSING, it should be setup in head.S!\n");
294 		return;
295 	}
296 
297 	p4d_page = p4d_offset(pgd, 0);
298 	set_pte_vaddr_p4d(p4d_page, vaddr, pteval);
299 }
300 
301 pmd_t * __init populate_extra_pmd(unsigned long vaddr)
302 {
303 	pgd_t *pgd;
304 	p4d_t *p4d;
305 	pud_t *pud;
306 
307 	pgd = pgd_offset_k(vaddr);
308 	p4d = fill_p4d(pgd, vaddr);
309 	pud = fill_pud(p4d, vaddr);
310 	return fill_pmd(pud, vaddr);
311 }
312 
313 pte_t * __init populate_extra_pte(unsigned long vaddr)
314 {
315 	pmd_t *pmd;
316 
317 	pmd = populate_extra_pmd(vaddr);
318 	return fill_pte(pmd, vaddr);
319 }
320 
321 /*
322  * Create large page table mappings for a range of physical addresses.
323  */
324 static void __init __init_extra_mapping(unsigned long phys, unsigned long size,
325 					enum page_cache_mode cache)
326 {
327 	pgd_t *pgd;
328 	p4d_t *p4d;
329 	pud_t *pud;
330 	pmd_t *pmd;
331 	pgprot_t prot;
332 
333 	pgprot_val(prot) = pgprot_val(PAGE_KERNEL_LARGE) |
334 		pgprot_val(pgprot_4k_2_large(cachemode2pgprot(cache)));
335 	BUG_ON((phys & ~PMD_MASK) || (size & ~PMD_MASK));
336 	for (; size; phys += PMD_SIZE, size -= PMD_SIZE) {
337 		pgd = pgd_offset_k((unsigned long)__va(phys));
338 		if (pgd_none(*pgd)) {
339 			p4d = (p4d_t *) spp_getpage();
340 			set_pgd(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE |
341 						_PAGE_USER));
342 		}
343 		p4d = p4d_offset(pgd, (unsigned long)__va(phys));
344 		if (p4d_none(*p4d)) {
345 			pud = (pud_t *) spp_getpage();
346 			set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE |
347 						_PAGE_USER));
348 		}
349 		pud = pud_offset(p4d, (unsigned long)__va(phys));
350 		if (pud_none(*pud)) {
351 			pmd = (pmd_t *) spp_getpage();
352 			set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE |
353 						_PAGE_USER));
354 		}
355 		pmd = pmd_offset(pud, phys);
356 		BUG_ON(!pmd_none(*pmd));
357 		set_pmd(pmd, __pmd(phys | pgprot_val(prot)));
358 	}
359 }
360 
361 void __init init_extra_mapping_wb(unsigned long phys, unsigned long size)
362 {
363 	__init_extra_mapping(phys, size, _PAGE_CACHE_MODE_WB);
364 }
365 
366 void __init init_extra_mapping_uc(unsigned long phys, unsigned long size)
367 {
368 	__init_extra_mapping(phys, size, _PAGE_CACHE_MODE_UC);
369 }
370 
371 /*
372  * The head.S code sets up the kernel high mapping:
373  *
374  *   from __START_KERNEL_map to __START_KERNEL_map + size (== _end-_text)
375  *
376  * phys_base holds the negative offset to the kernel, which is added
377  * to the compile time generated pmds. This results in invalid pmds up
378  * to the point where we hit the physaddr 0 mapping.
379  *
380  * We limit the mappings to the region from _text to _brk_end.  _brk_end
381  * is rounded up to the 2MB boundary. This catches the invalid pmds as
382  * well, as they are located before _text:
383  */
384 void __init cleanup_highmap(void)
385 {
386 	unsigned long vaddr = __START_KERNEL_map;
387 	unsigned long vaddr_end = __START_KERNEL_map + KERNEL_IMAGE_SIZE;
388 	unsigned long end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
389 	pmd_t *pmd = level2_kernel_pgt;
390 
391 	/*
392 	 * Native path, max_pfn_mapped is not set yet.
393 	 * Xen has valid max_pfn_mapped set in
394 	 *	arch/x86/xen/mmu.c:xen_setup_kernel_pagetable().
395 	 */
396 	if (max_pfn_mapped)
397 		vaddr_end = __START_KERNEL_map + (max_pfn_mapped << PAGE_SHIFT);
398 
399 	for (; vaddr + PMD_SIZE - 1 < vaddr_end; pmd++, vaddr += PMD_SIZE) {
400 		if (pmd_none(*pmd))
401 			continue;
402 		if (vaddr < (unsigned long) _text || vaddr > end)
403 			set_pmd(pmd, __pmd(0));
404 	}
405 }
406 
407 /*
408  * Create PTE level page table mapping for physical addresses.
409  * It returns the last physical address mapped.
410  */
411 static unsigned long __meminit
412 phys_pte_init(pte_t *pte_page, unsigned long paddr, unsigned long paddr_end,
413 	      pgprot_t prot)
414 {
415 	unsigned long pages = 0, paddr_next;
416 	unsigned long paddr_last = paddr_end;
417 	pte_t *pte;
418 	int i;
419 
420 	pte = pte_page + pte_index(paddr);
421 	i = pte_index(paddr);
422 
423 	for (; i < PTRS_PER_PTE; i++, paddr = paddr_next, pte++) {
424 		paddr_next = (paddr & PAGE_MASK) + PAGE_SIZE;
425 		if (paddr >= paddr_end) {
426 			if (!after_bootmem &&
427 			    !e820__mapped_any(paddr & PAGE_MASK, paddr_next,
428 					     E820_TYPE_RAM) &&
429 			    !e820__mapped_any(paddr & PAGE_MASK, paddr_next,
430 					     E820_TYPE_RESERVED_KERN))
431 				set_pte(pte, __pte(0));
432 			continue;
433 		}
434 
435 		/*
436 		 * We will re-use the existing mapping.
437 		 * Xen for example has some special requirements, like mapping
438 		 * pagetable pages as RO. So assume someone who pre-setup
439 		 * these mappings are more intelligent.
440 		 */
441 		if (!pte_none(*pte)) {
442 			if (!after_bootmem)
443 				pages++;
444 			continue;
445 		}
446 
447 		if (0)
448 			pr_info("   pte=%p addr=%lx pte=%016lx\n", pte, paddr,
449 				pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL).pte);
450 		pages++;
451 		set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot));
452 		paddr_last = (paddr & PAGE_MASK) + PAGE_SIZE;
453 	}
454 
455 	update_page_count(PG_LEVEL_4K, pages);
456 
457 	return paddr_last;
458 }
459 
460 /*
461  * Create PMD level page table mapping for physical addresses. The virtual
462  * and physical address have to be aligned at this level.
463  * It returns the last physical address mapped.
464  */
465 static unsigned long __meminit
466 phys_pmd_init(pmd_t *pmd_page, unsigned long paddr, unsigned long paddr_end,
467 	      unsigned long page_size_mask, pgprot_t prot)
468 {
469 	unsigned long pages = 0, paddr_next;
470 	unsigned long paddr_last = paddr_end;
471 
472 	int i = pmd_index(paddr);
473 
474 	for (; i < PTRS_PER_PMD; i++, paddr = paddr_next) {
475 		pmd_t *pmd = pmd_page + pmd_index(paddr);
476 		pte_t *pte;
477 		pgprot_t new_prot = prot;
478 
479 		paddr_next = (paddr & PMD_MASK) + PMD_SIZE;
480 		if (paddr >= paddr_end) {
481 			if (!after_bootmem &&
482 			    !e820__mapped_any(paddr & PMD_MASK, paddr_next,
483 					     E820_TYPE_RAM) &&
484 			    !e820__mapped_any(paddr & PMD_MASK, paddr_next,
485 					     E820_TYPE_RESERVED_KERN))
486 				set_pmd(pmd, __pmd(0));
487 			continue;
488 		}
489 
490 		if (!pmd_none(*pmd)) {
491 			if (!pmd_large(*pmd)) {
492 				spin_lock(&init_mm.page_table_lock);
493 				pte = (pte_t *)pmd_page_vaddr(*pmd);
494 				paddr_last = phys_pte_init(pte, paddr,
495 							   paddr_end, prot);
496 				spin_unlock(&init_mm.page_table_lock);
497 				continue;
498 			}
499 			/*
500 			 * If we are ok with PG_LEVEL_2M mapping, then we will
501 			 * use the existing mapping,
502 			 *
503 			 * Otherwise, we will split the large page mapping but
504 			 * use the same existing protection bits except for
505 			 * large page, so that we don't violate Intel's TLB
506 			 * Application note (317080) which says, while changing
507 			 * the page sizes, new and old translations should
508 			 * not differ with respect to page frame and
509 			 * attributes.
510 			 */
511 			if (page_size_mask & (1 << PG_LEVEL_2M)) {
512 				if (!after_bootmem)
513 					pages++;
514 				paddr_last = paddr_next;
515 				continue;
516 			}
517 			new_prot = pte_pgprot(pte_clrhuge(*(pte_t *)pmd));
518 		}
519 
520 		if (page_size_mask & (1<<PG_LEVEL_2M)) {
521 			pages++;
522 			spin_lock(&init_mm.page_table_lock);
523 			set_pte((pte_t *)pmd,
524 				pfn_pte((paddr & PMD_MASK) >> PAGE_SHIFT,
525 					__pgprot(pgprot_val(prot) | _PAGE_PSE)));
526 			spin_unlock(&init_mm.page_table_lock);
527 			paddr_last = paddr_next;
528 			continue;
529 		}
530 
531 		pte = alloc_low_page();
532 		paddr_last = phys_pte_init(pte, paddr, paddr_end, new_prot);
533 
534 		spin_lock(&init_mm.page_table_lock);
535 		pmd_populate_kernel(&init_mm, pmd, pte);
536 		spin_unlock(&init_mm.page_table_lock);
537 	}
538 	update_page_count(PG_LEVEL_2M, pages);
539 	return paddr_last;
540 }
541 
542 /*
543  * Create PUD level page table mapping for physical addresses. The virtual
544  * and physical address do not have to be aligned at this level. KASLR can
545  * randomize virtual addresses up to this level.
546  * It returns the last physical address mapped.
547  */
548 static unsigned long __meminit
549 phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end,
550 	      unsigned long page_size_mask)
551 {
552 	unsigned long pages = 0, paddr_next;
553 	unsigned long paddr_last = paddr_end;
554 	unsigned long vaddr = (unsigned long)__va(paddr);
555 	int i = pud_index(vaddr);
556 
557 	for (; i < PTRS_PER_PUD; i++, paddr = paddr_next) {
558 		pud_t *pud;
559 		pmd_t *pmd;
560 		pgprot_t prot = PAGE_KERNEL;
561 
562 		vaddr = (unsigned long)__va(paddr);
563 		pud = pud_page + pud_index(vaddr);
564 		paddr_next = (paddr & PUD_MASK) + PUD_SIZE;
565 
566 		if (paddr >= paddr_end) {
567 			if (!after_bootmem &&
568 			    !e820__mapped_any(paddr & PUD_MASK, paddr_next,
569 					     E820_TYPE_RAM) &&
570 			    !e820__mapped_any(paddr & PUD_MASK, paddr_next,
571 					     E820_TYPE_RESERVED_KERN))
572 				set_pud(pud, __pud(0));
573 			continue;
574 		}
575 
576 		if (!pud_none(*pud)) {
577 			if (!pud_large(*pud)) {
578 				pmd = pmd_offset(pud, 0);
579 				paddr_last = phys_pmd_init(pmd, paddr,
580 							   paddr_end,
581 							   page_size_mask,
582 							   prot);
583 				__flush_tlb_all();
584 				continue;
585 			}
586 			/*
587 			 * If we are ok with PG_LEVEL_1G mapping, then we will
588 			 * use the existing mapping.
589 			 *
590 			 * Otherwise, we will split the gbpage mapping but use
591 			 * the same existing protection  bits except for large
592 			 * page, so that we don't violate Intel's TLB
593 			 * Application note (317080) which says, while changing
594 			 * the page sizes, new and old translations should
595 			 * not differ with respect to page frame and
596 			 * attributes.
597 			 */
598 			if (page_size_mask & (1 << PG_LEVEL_1G)) {
599 				if (!after_bootmem)
600 					pages++;
601 				paddr_last = paddr_next;
602 				continue;
603 			}
604 			prot = pte_pgprot(pte_clrhuge(*(pte_t *)pud));
605 		}
606 
607 		if (page_size_mask & (1<<PG_LEVEL_1G)) {
608 			pages++;
609 			spin_lock(&init_mm.page_table_lock);
610 			set_pte((pte_t *)pud,
611 				pfn_pte((paddr & PUD_MASK) >> PAGE_SHIFT,
612 					PAGE_KERNEL_LARGE));
613 			spin_unlock(&init_mm.page_table_lock);
614 			paddr_last = paddr_next;
615 			continue;
616 		}
617 
618 		pmd = alloc_low_page();
619 		paddr_last = phys_pmd_init(pmd, paddr, paddr_end,
620 					   page_size_mask, prot);
621 
622 		spin_lock(&init_mm.page_table_lock);
623 		pud_populate(&init_mm, pud, pmd);
624 		spin_unlock(&init_mm.page_table_lock);
625 	}
626 	__flush_tlb_all();
627 
628 	update_page_count(PG_LEVEL_1G, pages);
629 
630 	return paddr_last;
631 }
632 
633 static unsigned long __meminit
634 phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, unsigned long paddr_end,
635 	      unsigned long page_size_mask)
636 {
637 	unsigned long paddr_next, paddr_last = paddr_end;
638 	unsigned long vaddr = (unsigned long)__va(paddr);
639 	int i = p4d_index(vaddr);
640 
641 	if (!pgtable_l5_enabled)
642 		return phys_pud_init((pud_t *) p4d_page, paddr, paddr_end, page_size_mask);
643 
644 	for (; i < PTRS_PER_P4D; i++, paddr = paddr_next) {
645 		p4d_t *p4d;
646 		pud_t *pud;
647 
648 		vaddr = (unsigned long)__va(paddr);
649 		p4d = p4d_page + p4d_index(vaddr);
650 		paddr_next = (paddr & P4D_MASK) + P4D_SIZE;
651 
652 		if (paddr >= paddr_end) {
653 			if (!after_bootmem &&
654 			    !e820__mapped_any(paddr & P4D_MASK, paddr_next,
655 					     E820_TYPE_RAM) &&
656 			    !e820__mapped_any(paddr & P4D_MASK, paddr_next,
657 					     E820_TYPE_RESERVED_KERN))
658 				set_p4d(p4d, __p4d(0));
659 			continue;
660 		}
661 
662 		if (!p4d_none(*p4d)) {
663 			pud = pud_offset(p4d, 0);
664 			paddr_last = phys_pud_init(pud, paddr,
665 					paddr_end,
666 					page_size_mask);
667 			__flush_tlb_all();
668 			continue;
669 		}
670 
671 		pud = alloc_low_page();
672 		paddr_last = phys_pud_init(pud, paddr, paddr_end,
673 					   page_size_mask);
674 
675 		spin_lock(&init_mm.page_table_lock);
676 		p4d_populate(&init_mm, p4d, pud);
677 		spin_unlock(&init_mm.page_table_lock);
678 	}
679 	__flush_tlb_all();
680 
681 	return paddr_last;
682 }
683 
684 /*
685  * Create page table mapping for the physical memory for specific physical
686  * addresses. The virtual and physical addresses have to be aligned on PMD level
687  * down. It returns the last physical address mapped.
688  */
689 unsigned long __meminit
690 kernel_physical_mapping_init(unsigned long paddr_start,
691 			     unsigned long paddr_end,
692 			     unsigned long page_size_mask)
693 {
694 	bool pgd_changed = false;
695 	unsigned long vaddr, vaddr_start, vaddr_end, vaddr_next, paddr_last;
696 
697 	paddr_last = paddr_end;
698 	vaddr = (unsigned long)__va(paddr_start);
699 	vaddr_end = (unsigned long)__va(paddr_end);
700 	vaddr_start = vaddr;
701 
702 	for (; vaddr < vaddr_end; vaddr = vaddr_next) {
703 		pgd_t *pgd = pgd_offset_k(vaddr);
704 		p4d_t *p4d;
705 
706 		vaddr_next = (vaddr & PGDIR_MASK) + PGDIR_SIZE;
707 
708 		if (pgd_val(*pgd)) {
709 			p4d = (p4d_t *)pgd_page_vaddr(*pgd);
710 			paddr_last = phys_p4d_init(p4d, __pa(vaddr),
711 						   __pa(vaddr_end),
712 						   page_size_mask);
713 			continue;
714 		}
715 
716 		p4d = alloc_low_page();
717 		paddr_last = phys_p4d_init(p4d, __pa(vaddr), __pa(vaddr_end),
718 					   page_size_mask);
719 
720 		spin_lock(&init_mm.page_table_lock);
721 		if (pgtable_l5_enabled)
722 			pgd_populate(&init_mm, pgd, p4d);
723 		else
724 			p4d_populate(&init_mm, p4d_offset(pgd, vaddr), (pud_t *) p4d);
725 		spin_unlock(&init_mm.page_table_lock);
726 		pgd_changed = true;
727 	}
728 
729 	if (pgd_changed)
730 		sync_global_pgds(vaddr_start, vaddr_end - 1);
731 
732 	__flush_tlb_all();
733 
734 	return paddr_last;
735 }
736 
737 #ifndef CONFIG_NUMA
738 void __init initmem_init(void)
739 {
740 	memblock_set_node(0, (phys_addr_t)ULLONG_MAX, &memblock.memory, 0);
741 }
742 #endif
743 
744 void __init paging_init(void)
745 {
746 	sparse_memory_present_with_active_regions(MAX_NUMNODES);
747 	sparse_init();
748 
749 	/*
750 	 * clear the default setting with node 0
751 	 * note: don't use nodes_clear here, that is really clearing when
752 	 *	 numa support is not compiled in, and later node_set_state
753 	 *	 will not set it back.
754 	 */
755 	node_clear_state(0, N_MEMORY);
756 	if (N_MEMORY != N_NORMAL_MEMORY)
757 		node_clear_state(0, N_NORMAL_MEMORY);
758 
759 	zone_sizes_init();
760 }
761 
762 /*
763  * Memory hotplug specific functions
764  */
765 #ifdef CONFIG_MEMORY_HOTPLUG
766 /*
767  * After memory hotplug the variables max_pfn, max_low_pfn and high_memory need
768  * updating.
769  */
770 static void update_end_of_memory_vars(u64 start, u64 size)
771 {
772 	unsigned long end_pfn = PFN_UP(start + size);
773 
774 	if (end_pfn > max_pfn) {
775 		max_pfn = end_pfn;
776 		max_low_pfn = end_pfn;
777 		high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
778 	}
779 }
780 
781 int add_pages(int nid, unsigned long start_pfn, unsigned long nr_pages,
782 		struct vmem_altmap *altmap, bool want_memblock)
783 {
784 	int ret;
785 
786 	ret = __add_pages(nid, start_pfn, nr_pages, altmap, want_memblock);
787 	WARN_ON_ONCE(ret);
788 
789 	/* update max_pfn, max_low_pfn and high_memory */
790 	update_end_of_memory_vars(start_pfn << PAGE_SHIFT,
791 				  nr_pages << PAGE_SHIFT);
792 
793 	return ret;
794 }
795 
796 int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap,
797 		bool want_memblock)
798 {
799 	unsigned long start_pfn = start >> PAGE_SHIFT;
800 	unsigned long nr_pages = size >> PAGE_SHIFT;
801 
802 	init_memory_mapping(start, start + size);
803 
804 	return add_pages(nid, start_pfn, nr_pages, altmap, want_memblock);
805 }
806 
807 #define PAGE_INUSE 0xFD
808 
809 static void __meminit free_pagetable(struct page *page, int order)
810 {
811 	unsigned long magic;
812 	unsigned int nr_pages = 1 << order;
813 
814 	/* bootmem page has reserved flag */
815 	if (PageReserved(page)) {
816 		__ClearPageReserved(page);
817 
818 		magic = (unsigned long)page->freelist;
819 		if (magic == SECTION_INFO || magic == MIX_SECTION_INFO) {
820 			while (nr_pages--)
821 				put_page_bootmem(page++);
822 		} else
823 			while (nr_pages--)
824 				free_reserved_page(page++);
825 	} else
826 		free_pages((unsigned long)page_address(page), order);
827 }
828 
829 static void __meminit free_hugepage_table(struct page *page,
830 		struct vmem_altmap *altmap)
831 {
832 	if (altmap)
833 		vmem_altmap_free(altmap, PMD_SIZE / PAGE_SIZE);
834 	else
835 		free_pagetable(page, get_order(PMD_SIZE));
836 }
837 
838 static void __meminit free_pte_table(pte_t *pte_start, pmd_t *pmd)
839 {
840 	pte_t *pte;
841 	int i;
842 
843 	for (i = 0; i < PTRS_PER_PTE; i++) {
844 		pte = pte_start + i;
845 		if (!pte_none(*pte))
846 			return;
847 	}
848 
849 	/* free a pte talbe */
850 	free_pagetable(pmd_page(*pmd), 0);
851 	spin_lock(&init_mm.page_table_lock);
852 	pmd_clear(pmd);
853 	spin_unlock(&init_mm.page_table_lock);
854 }
855 
856 static void __meminit free_pmd_table(pmd_t *pmd_start, pud_t *pud)
857 {
858 	pmd_t *pmd;
859 	int i;
860 
861 	for (i = 0; i < PTRS_PER_PMD; i++) {
862 		pmd = pmd_start + i;
863 		if (!pmd_none(*pmd))
864 			return;
865 	}
866 
867 	/* free a pmd talbe */
868 	free_pagetable(pud_page(*pud), 0);
869 	spin_lock(&init_mm.page_table_lock);
870 	pud_clear(pud);
871 	spin_unlock(&init_mm.page_table_lock);
872 }
873 
874 static void __meminit free_pud_table(pud_t *pud_start, p4d_t *p4d)
875 {
876 	pud_t *pud;
877 	int i;
878 
879 	for (i = 0; i < PTRS_PER_PUD; i++) {
880 		pud = pud_start + i;
881 		if (!pud_none(*pud))
882 			return;
883 	}
884 
885 	/* free a pud talbe */
886 	free_pagetable(p4d_page(*p4d), 0);
887 	spin_lock(&init_mm.page_table_lock);
888 	p4d_clear(p4d);
889 	spin_unlock(&init_mm.page_table_lock);
890 }
891 
892 static void __meminit
893 remove_pte_table(pte_t *pte_start, unsigned long addr, unsigned long end,
894 		 bool direct)
895 {
896 	unsigned long next, pages = 0;
897 	pte_t *pte;
898 	void *page_addr;
899 	phys_addr_t phys_addr;
900 
901 	pte = pte_start + pte_index(addr);
902 	for (; addr < end; addr = next, pte++) {
903 		next = (addr + PAGE_SIZE) & PAGE_MASK;
904 		if (next > end)
905 			next = end;
906 
907 		if (!pte_present(*pte))
908 			continue;
909 
910 		/*
911 		 * We mapped [0,1G) memory as identity mapping when
912 		 * initializing, in arch/x86/kernel/head_64.S. These
913 		 * pagetables cannot be removed.
914 		 */
915 		phys_addr = pte_val(*pte) + (addr & PAGE_MASK);
916 		if (phys_addr < (phys_addr_t)0x40000000)
917 			return;
918 
919 		if (PAGE_ALIGNED(addr) && PAGE_ALIGNED(next)) {
920 			/*
921 			 * Do not free direct mapping pages since they were
922 			 * freed when offlining, or simplely not in use.
923 			 */
924 			if (!direct)
925 				free_pagetable(pte_page(*pte), 0);
926 
927 			spin_lock(&init_mm.page_table_lock);
928 			pte_clear(&init_mm, addr, pte);
929 			spin_unlock(&init_mm.page_table_lock);
930 
931 			/* For non-direct mapping, pages means nothing. */
932 			pages++;
933 		} else {
934 			/*
935 			 * If we are here, we are freeing vmemmap pages since
936 			 * direct mapped memory ranges to be freed are aligned.
937 			 *
938 			 * If we are not removing the whole page, it means
939 			 * other page structs in this page are being used and
940 			 * we canot remove them. So fill the unused page_structs
941 			 * with 0xFD, and remove the page when it is wholly
942 			 * filled with 0xFD.
943 			 */
944 			memset((void *)addr, PAGE_INUSE, next - addr);
945 
946 			page_addr = page_address(pte_page(*pte));
947 			if (!memchr_inv(page_addr, PAGE_INUSE, PAGE_SIZE)) {
948 				free_pagetable(pte_page(*pte), 0);
949 
950 				spin_lock(&init_mm.page_table_lock);
951 				pte_clear(&init_mm, addr, pte);
952 				spin_unlock(&init_mm.page_table_lock);
953 			}
954 		}
955 	}
956 
957 	/* Call free_pte_table() in remove_pmd_table(). */
958 	flush_tlb_all();
959 	if (direct)
960 		update_page_count(PG_LEVEL_4K, -pages);
961 }
962 
963 static void __meminit
964 remove_pmd_table(pmd_t *pmd_start, unsigned long addr, unsigned long end,
965 		 bool direct, struct vmem_altmap *altmap)
966 {
967 	unsigned long next, pages = 0;
968 	pte_t *pte_base;
969 	pmd_t *pmd;
970 	void *page_addr;
971 
972 	pmd = pmd_start + pmd_index(addr);
973 	for (; addr < end; addr = next, pmd++) {
974 		next = pmd_addr_end(addr, end);
975 
976 		if (!pmd_present(*pmd))
977 			continue;
978 
979 		if (pmd_large(*pmd)) {
980 			if (IS_ALIGNED(addr, PMD_SIZE) &&
981 			    IS_ALIGNED(next, PMD_SIZE)) {
982 				if (!direct)
983 					free_hugepage_table(pmd_page(*pmd),
984 							    altmap);
985 
986 				spin_lock(&init_mm.page_table_lock);
987 				pmd_clear(pmd);
988 				spin_unlock(&init_mm.page_table_lock);
989 				pages++;
990 			} else {
991 				/* If here, we are freeing vmemmap pages. */
992 				memset((void *)addr, PAGE_INUSE, next - addr);
993 
994 				page_addr = page_address(pmd_page(*pmd));
995 				if (!memchr_inv(page_addr, PAGE_INUSE,
996 						PMD_SIZE)) {
997 					free_hugepage_table(pmd_page(*pmd),
998 							    altmap);
999 
1000 					spin_lock(&init_mm.page_table_lock);
1001 					pmd_clear(pmd);
1002 					spin_unlock(&init_mm.page_table_lock);
1003 				}
1004 			}
1005 
1006 			continue;
1007 		}
1008 
1009 		pte_base = (pte_t *)pmd_page_vaddr(*pmd);
1010 		remove_pte_table(pte_base, addr, next, direct);
1011 		free_pte_table(pte_base, pmd);
1012 	}
1013 
1014 	/* Call free_pmd_table() in remove_pud_table(). */
1015 	if (direct)
1016 		update_page_count(PG_LEVEL_2M, -pages);
1017 }
1018 
1019 static void __meminit
1020 remove_pud_table(pud_t *pud_start, unsigned long addr, unsigned long end,
1021 		 struct vmem_altmap *altmap, bool direct)
1022 {
1023 	unsigned long next, pages = 0;
1024 	pmd_t *pmd_base;
1025 	pud_t *pud;
1026 	void *page_addr;
1027 
1028 	pud = pud_start + pud_index(addr);
1029 	for (; addr < end; addr = next, pud++) {
1030 		next = pud_addr_end(addr, end);
1031 
1032 		if (!pud_present(*pud))
1033 			continue;
1034 
1035 		if (pud_large(*pud)) {
1036 			if (IS_ALIGNED(addr, PUD_SIZE) &&
1037 			    IS_ALIGNED(next, PUD_SIZE)) {
1038 				if (!direct)
1039 					free_pagetable(pud_page(*pud),
1040 						       get_order(PUD_SIZE));
1041 
1042 				spin_lock(&init_mm.page_table_lock);
1043 				pud_clear(pud);
1044 				spin_unlock(&init_mm.page_table_lock);
1045 				pages++;
1046 			} else {
1047 				/* If here, we are freeing vmemmap pages. */
1048 				memset((void *)addr, PAGE_INUSE, next - addr);
1049 
1050 				page_addr = page_address(pud_page(*pud));
1051 				if (!memchr_inv(page_addr, PAGE_INUSE,
1052 						PUD_SIZE)) {
1053 					free_pagetable(pud_page(*pud),
1054 						       get_order(PUD_SIZE));
1055 
1056 					spin_lock(&init_mm.page_table_lock);
1057 					pud_clear(pud);
1058 					spin_unlock(&init_mm.page_table_lock);
1059 				}
1060 			}
1061 
1062 			continue;
1063 		}
1064 
1065 		pmd_base = pmd_offset(pud, 0);
1066 		remove_pmd_table(pmd_base, addr, next, direct, altmap);
1067 		free_pmd_table(pmd_base, pud);
1068 	}
1069 
1070 	if (direct)
1071 		update_page_count(PG_LEVEL_1G, -pages);
1072 }
1073 
1074 static void __meminit
1075 remove_p4d_table(p4d_t *p4d_start, unsigned long addr, unsigned long end,
1076 		 struct vmem_altmap *altmap, bool direct)
1077 {
1078 	unsigned long next, pages = 0;
1079 	pud_t *pud_base;
1080 	p4d_t *p4d;
1081 
1082 	p4d = p4d_start + p4d_index(addr);
1083 	for (; addr < end; addr = next, p4d++) {
1084 		next = p4d_addr_end(addr, end);
1085 
1086 		if (!p4d_present(*p4d))
1087 			continue;
1088 
1089 		BUILD_BUG_ON(p4d_large(*p4d));
1090 
1091 		pud_base = pud_offset(p4d, 0);
1092 		remove_pud_table(pud_base, addr, next, altmap, direct);
1093 		/*
1094 		 * For 4-level page tables we do not want to free PUDs, but in the
1095 		 * 5-level case we should free them. This code will have to change
1096 		 * to adapt for boot-time switching between 4 and 5 level page tables.
1097 		 */
1098 		if (pgtable_l5_enabled)
1099 			free_pud_table(pud_base, p4d);
1100 	}
1101 
1102 	if (direct)
1103 		update_page_count(PG_LEVEL_512G, -pages);
1104 }
1105 
1106 /* start and end are both virtual address. */
1107 static void __meminit
1108 remove_pagetable(unsigned long start, unsigned long end, bool direct,
1109 		struct vmem_altmap *altmap)
1110 {
1111 	unsigned long next;
1112 	unsigned long addr;
1113 	pgd_t *pgd;
1114 	p4d_t *p4d;
1115 
1116 	for (addr = start; addr < end; addr = next) {
1117 		next = pgd_addr_end(addr, end);
1118 
1119 		pgd = pgd_offset_k(addr);
1120 		if (!pgd_present(*pgd))
1121 			continue;
1122 
1123 		p4d = p4d_offset(pgd, 0);
1124 		remove_p4d_table(p4d, addr, next, altmap, direct);
1125 	}
1126 
1127 	flush_tlb_all();
1128 }
1129 
1130 void __ref vmemmap_free(unsigned long start, unsigned long end,
1131 		struct vmem_altmap *altmap)
1132 {
1133 	remove_pagetable(start, end, false, altmap);
1134 }
1135 
1136 #ifdef CONFIG_MEMORY_HOTREMOVE
1137 static void __meminit
1138 kernel_physical_mapping_remove(unsigned long start, unsigned long end)
1139 {
1140 	start = (unsigned long)__va(start);
1141 	end = (unsigned long)__va(end);
1142 
1143 	remove_pagetable(start, end, true, NULL);
1144 }
1145 
1146 int __ref arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
1147 {
1148 	unsigned long start_pfn = start >> PAGE_SHIFT;
1149 	unsigned long nr_pages = size >> PAGE_SHIFT;
1150 	struct page *page = pfn_to_page(start_pfn);
1151 	struct zone *zone;
1152 	int ret;
1153 
1154 	/* With altmap the first mapped page is offset from @start */
1155 	if (altmap)
1156 		page += vmem_altmap_offset(altmap);
1157 	zone = page_zone(page);
1158 	ret = __remove_pages(zone, start_pfn, nr_pages, altmap);
1159 	WARN_ON_ONCE(ret);
1160 	kernel_physical_mapping_remove(start, start + size);
1161 
1162 	return ret;
1163 }
1164 #endif
1165 #endif /* CONFIG_MEMORY_HOTPLUG */
1166 
1167 static struct kcore_list kcore_vsyscall;
1168 
1169 static void __init register_page_bootmem_info(void)
1170 {
1171 #ifdef CONFIG_NUMA
1172 	int i;
1173 
1174 	for_each_online_node(i)
1175 		register_page_bootmem_info_node(NODE_DATA(i));
1176 #endif
1177 }
1178 
1179 void __init mem_init(void)
1180 {
1181 	pci_iommu_alloc();
1182 
1183 	/* clear_bss() already clear the empty_zero_page */
1184 
1185 	/* this will put all memory onto the freelists */
1186 	free_all_bootmem();
1187 	after_bootmem = 1;
1188 
1189 	/*
1190 	 * Must be done after boot memory is put on freelist, because here we
1191 	 * might set fields in deferred struct pages that have not yet been
1192 	 * initialized, and free_all_bootmem() initializes all the reserved
1193 	 * deferred pages for us.
1194 	 */
1195 	register_page_bootmem_info();
1196 
1197 	/* Register memory areas for /proc/kcore */
1198 	if (get_gate_vma(&init_mm))
1199 		kclist_add(&kcore_vsyscall, (void *)VSYSCALL_ADDR, PAGE_SIZE, KCORE_USER);
1200 
1201 	mem_init_print_info(NULL);
1202 }
1203 
1204 int kernel_set_to_readonly;
1205 
1206 void set_kernel_text_rw(void)
1207 {
1208 	unsigned long start = PFN_ALIGN(_text);
1209 	unsigned long end = PFN_ALIGN(__stop___ex_table);
1210 
1211 	if (!kernel_set_to_readonly)
1212 		return;
1213 
1214 	pr_debug("Set kernel text: %lx - %lx for read write\n",
1215 		 start, end);
1216 
1217 	/*
1218 	 * Make the kernel identity mapping for text RW. Kernel text
1219 	 * mapping will always be RO. Refer to the comment in
1220 	 * static_protections() in pageattr.c
1221 	 */
1222 	set_memory_rw(start, (end - start) >> PAGE_SHIFT);
1223 }
1224 
1225 void set_kernel_text_ro(void)
1226 {
1227 	unsigned long start = PFN_ALIGN(_text);
1228 	unsigned long end = PFN_ALIGN(__stop___ex_table);
1229 
1230 	if (!kernel_set_to_readonly)
1231 		return;
1232 
1233 	pr_debug("Set kernel text: %lx - %lx for read only\n",
1234 		 start, end);
1235 
1236 	/*
1237 	 * Set the kernel identity mapping for text RO.
1238 	 */
1239 	set_memory_ro(start, (end - start) >> PAGE_SHIFT);
1240 }
1241 
1242 void mark_rodata_ro(void)
1243 {
1244 	unsigned long start = PFN_ALIGN(_text);
1245 	unsigned long rodata_start = PFN_ALIGN(__start_rodata);
1246 	unsigned long end = (unsigned long) &__end_rodata_hpage_align;
1247 	unsigned long text_end = PFN_ALIGN(&__stop___ex_table);
1248 	unsigned long rodata_end = PFN_ALIGN(&__end_rodata);
1249 	unsigned long all_end;
1250 
1251 	printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1252 	       (end - start) >> 10);
1253 	set_memory_ro(start, (end - start) >> PAGE_SHIFT);
1254 
1255 	kernel_set_to_readonly = 1;
1256 
1257 	/*
1258 	 * The rodata/data/bss/brk section (but not the kernel text!)
1259 	 * should also be not-executable.
1260 	 *
1261 	 * We align all_end to PMD_SIZE because the existing mapping
1262 	 * is a full PMD. If we would align _brk_end to PAGE_SIZE we
1263 	 * split the PMD and the reminder between _brk_end and the end
1264 	 * of the PMD will remain mapped executable.
1265 	 *
1266 	 * Any PMD which was setup after the one which covers _brk_end
1267 	 * has been zapped already via cleanup_highmem().
1268 	 */
1269 	all_end = roundup((unsigned long)_brk_end, PMD_SIZE);
1270 	set_memory_nx(text_end, (all_end - text_end) >> PAGE_SHIFT);
1271 
1272 #ifdef CONFIG_CPA_DEBUG
1273 	printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, end);
1274 	set_memory_rw(start, (end-start) >> PAGE_SHIFT);
1275 
1276 	printk(KERN_INFO "Testing CPA: again\n");
1277 	set_memory_ro(start, (end-start) >> PAGE_SHIFT);
1278 #endif
1279 
1280 	free_init_pages("unused kernel",
1281 			(unsigned long) __va(__pa_symbol(text_end)),
1282 			(unsigned long) __va(__pa_symbol(rodata_start)));
1283 	free_init_pages("unused kernel",
1284 			(unsigned long) __va(__pa_symbol(rodata_end)),
1285 			(unsigned long) __va(__pa_symbol(_sdata)));
1286 
1287 	debug_checkwx();
1288 }
1289 
1290 int kern_addr_valid(unsigned long addr)
1291 {
1292 	unsigned long above = ((long)addr) >> __VIRTUAL_MASK_SHIFT;
1293 	pgd_t *pgd;
1294 	p4d_t *p4d;
1295 	pud_t *pud;
1296 	pmd_t *pmd;
1297 	pte_t *pte;
1298 
1299 	if (above != 0 && above != -1UL)
1300 		return 0;
1301 
1302 	pgd = pgd_offset_k(addr);
1303 	if (pgd_none(*pgd))
1304 		return 0;
1305 
1306 	p4d = p4d_offset(pgd, addr);
1307 	if (p4d_none(*p4d))
1308 		return 0;
1309 
1310 	pud = pud_offset(p4d, addr);
1311 	if (pud_none(*pud))
1312 		return 0;
1313 
1314 	if (pud_large(*pud))
1315 		return pfn_valid(pud_pfn(*pud));
1316 
1317 	pmd = pmd_offset(pud, addr);
1318 	if (pmd_none(*pmd))
1319 		return 0;
1320 
1321 	if (pmd_large(*pmd))
1322 		return pfn_valid(pmd_pfn(*pmd));
1323 
1324 	pte = pte_offset_kernel(pmd, addr);
1325 	if (pte_none(*pte))
1326 		return 0;
1327 
1328 	return pfn_valid(pte_pfn(*pte));
1329 }
1330 
1331 static unsigned long probe_memory_block_size(void)
1332 {
1333 	unsigned long bz = MIN_MEMORY_BLOCK_SIZE;
1334 
1335 	/* if system is UV or has 64GB of RAM or more, use large blocks */
1336 	if (is_uv_system() || ((max_pfn << PAGE_SHIFT) >= (64UL << 30)))
1337 		bz = 2UL << 30; /* 2GB */
1338 
1339 	pr_info("x86/mm: Memory block size: %ldMB\n", bz >> 20);
1340 
1341 	return bz;
1342 }
1343 
1344 static unsigned long memory_block_size_probed;
1345 unsigned long memory_block_size_bytes(void)
1346 {
1347 	if (!memory_block_size_probed)
1348 		memory_block_size_probed = probe_memory_block_size();
1349 
1350 	return memory_block_size_probed;
1351 }
1352 
1353 #ifdef CONFIG_SPARSEMEM_VMEMMAP
1354 /*
1355  * Initialise the sparsemem vmemmap using huge-pages at the PMD level.
1356  */
1357 static long __meminitdata addr_start, addr_end;
1358 static void __meminitdata *p_start, *p_end;
1359 static int __meminitdata node_start;
1360 
1361 static int __meminit vmemmap_populate_hugepages(unsigned long start,
1362 		unsigned long end, int node, struct vmem_altmap *altmap)
1363 {
1364 	unsigned long addr;
1365 	unsigned long next;
1366 	pgd_t *pgd;
1367 	p4d_t *p4d;
1368 	pud_t *pud;
1369 	pmd_t *pmd;
1370 
1371 	for (addr = start; addr < end; addr = next) {
1372 		next = pmd_addr_end(addr, end);
1373 
1374 		pgd = vmemmap_pgd_populate(addr, node);
1375 		if (!pgd)
1376 			return -ENOMEM;
1377 
1378 		p4d = vmemmap_p4d_populate(pgd, addr, node);
1379 		if (!p4d)
1380 			return -ENOMEM;
1381 
1382 		pud = vmemmap_pud_populate(p4d, addr, node);
1383 		if (!pud)
1384 			return -ENOMEM;
1385 
1386 		pmd = pmd_offset(pud, addr);
1387 		if (pmd_none(*pmd)) {
1388 			void *p;
1389 
1390 			if (altmap)
1391 				p = altmap_alloc_block_buf(PMD_SIZE, altmap);
1392 			else
1393 				p = vmemmap_alloc_block_buf(PMD_SIZE, node);
1394 			if (p) {
1395 				pte_t entry;
1396 
1397 				entry = pfn_pte(__pa(p) >> PAGE_SHIFT,
1398 						PAGE_KERNEL_LARGE);
1399 				set_pmd(pmd, __pmd(pte_val(entry)));
1400 
1401 				/* check to see if we have contiguous blocks */
1402 				if (p_end != p || node_start != node) {
1403 					if (p_start)
1404 						pr_debug(" [%lx-%lx] PMD -> [%p-%p] on node %d\n",
1405 						       addr_start, addr_end-1, p_start, p_end-1, node_start);
1406 					addr_start = addr;
1407 					node_start = node;
1408 					p_start = p;
1409 				}
1410 
1411 				addr_end = addr + PMD_SIZE;
1412 				p_end = p + PMD_SIZE;
1413 				continue;
1414 			} else if (altmap)
1415 				return -ENOMEM; /* no fallback */
1416 		} else if (pmd_large(*pmd)) {
1417 			vmemmap_verify((pte_t *)pmd, node, addr, next);
1418 			continue;
1419 		}
1420 		if (vmemmap_populate_basepages(addr, next, node))
1421 			return -ENOMEM;
1422 	}
1423 	return 0;
1424 }
1425 
1426 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
1427 		struct vmem_altmap *altmap)
1428 {
1429 	int err;
1430 
1431 	if (boot_cpu_has(X86_FEATURE_PSE))
1432 		err = vmemmap_populate_hugepages(start, end, node, altmap);
1433 	else if (altmap) {
1434 		pr_err_once("%s: no cpu support for altmap allocations\n",
1435 				__func__);
1436 		err = -ENOMEM;
1437 	} else
1438 		err = vmemmap_populate_basepages(start, end, node);
1439 	if (!err)
1440 		sync_global_pgds(start, end - 1);
1441 	return err;
1442 }
1443 
1444 #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HAVE_BOOTMEM_INFO_NODE)
1445 void register_page_bootmem_memmap(unsigned long section_nr,
1446 				  struct page *start_page, unsigned long nr_pages)
1447 {
1448 	unsigned long addr = (unsigned long)start_page;
1449 	unsigned long end = (unsigned long)(start_page + nr_pages);
1450 	unsigned long next;
1451 	pgd_t *pgd;
1452 	p4d_t *p4d;
1453 	pud_t *pud;
1454 	pmd_t *pmd;
1455 	unsigned int nr_pmd_pages;
1456 	struct page *page;
1457 
1458 	for (; addr < end; addr = next) {
1459 		pte_t *pte = NULL;
1460 
1461 		pgd = pgd_offset_k(addr);
1462 		if (pgd_none(*pgd)) {
1463 			next = (addr + PAGE_SIZE) & PAGE_MASK;
1464 			continue;
1465 		}
1466 		get_page_bootmem(section_nr, pgd_page(*pgd), MIX_SECTION_INFO);
1467 
1468 		p4d = p4d_offset(pgd, addr);
1469 		if (p4d_none(*p4d)) {
1470 			next = (addr + PAGE_SIZE) & PAGE_MASK;
1471 			continue;
1472 		}
1473 		get_page_bootmem(section_nr, p4d_page(*p4d), MIX_SECTION_INFO);
1474 
1475 		pud = pud_offset(p4d, addr);
1476 		if (pud_none(*pud)) {
1477 			next = (addr + PAGE_SIZE) & PAGE_MASK;
1478 			continue;
1479 		}
1480 		get_page_bootmem(section_nr, pud_page(*pud), MIX_SECTION_INFO);
1481 
1482 		if (!boot_cpu_has(X86_FEATURE_PSE)) {
1483 			next = (addr + PAGE_SIZE) & PAGE_MASK;
1484 			pmd = pmd_offset(pud, addr);
1485 			if (pmd_none(*pmd))
1486 				continue;
1487 			get_page_bootmem(section_nr, pmd_page(*pmd),
1488 					 MIX_SECTION_INFO);
1489 
1490 			pte = pte_offset_kernel(pmd, addr);
1491 			if (pte_none(*pte))
1492 				continue;
1493 			get_page_bootmem(section_nr, pte_page(*pte),
1494 					 SECTION_INFO);
1495 		} else {
1496 			next = pmd_addr_end(addr, end);
1497 
1498 			pmd = pmd_offset(pud, addr);
1499 			if (pmd_none(*pmd))
1500 				continue;
1501 
1502 			nr_pmd_pages = 1 << get_order(PMD_SIZE);
1503 			page = pmd_page(*pmd);
1504 			while (nr_pmd_pages--)
1505 				get_page_bootmem(section_nr, page++,
1506 						 SECTION_INFO);
1507 		}
1508 	}
1509 }
1510 #endif
1511 
1512 void __meminit vmemmap_populate_print_last(void)
1513 {
1514 	if (p_start) {
1515 		pr_debug(" [%lx-%lx] PMD -> [%p-%p] on node %d\n",
1516 			addr_start, addr_end-1, p_start, p_end-1, node_start);
1517 		p_start = NULL;
1518 		p_end = NULL;
1519 		node_start = 0;
1520 	}
1521 }
1522 #endif
1523