xref: /linux/mm/memblock.c (revision bdd1a21b52557ea8f61d0a5dc2f77151b576eb70)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Procedures for maintaining information about logical memory blocks.
4  *
5  * Peter Bergner, IBM Corp.	June 2001.
6  * Copyright (C) 2001 Peter Bergner.
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/slab.h>
11 #include <linux/init.h>
12 #include <linux/bitops.h>
13 #include <linux/poison.h>
14 #include <linux/pfn.h>
15 #include <linux/debugfs.h>
16 #include <linux/kmemleak.h>
17 #include <linux/seq_file.h>
18 #include <linux/memblock.h>
19 
20 #include <asm/sections.h>
21 #include <linux/io.h>
22 
23 #include "internal.h"
24 
25 #define INIT_MEMBLOCK_REGIONS			128
26 #define INIT_PHYSMEM_REGIONS			4
27 
28 #ifndef INIT_MEMBLOCK_RESERVED_REGIONS
29 # define INIT_MEMBLOCK_RESERVED_REGIONS		INIT_MEMBLOCK_REGIONS
30 #endif
31 
32 /**
33  * DOC: memblock overview
34  *
35  * Memblock is a method of managing memory regions during the early
36  * boot period when the usual kernel memory allocators are not up and
37  * running.
38  *
39  * Memblock views the system memory as collections of contiguous
40  * regions. There are several types of these collections:
41  *
42  * * ``memory`` - describes the physical memory available to the
43  *   kernel; this may differ from the actual physical memory installed
44  *   in the system, for instance when the memory is restricted with
45  *   ``mem=`` command line parameter
46  * * ``reserved`` - describes the regions that were allocated
47  * * ``physmem`` - describes the actual physical memory available during
48  *   boot regardless of the possible restrictions and memory hot(un)plug;
49  *   the ``physmem`` type is only available on some architectures.
50  *
51  * Each region is represented by struct memblock_region that
52  * defines the region extents, its attributes and NUMA node id on NUMA
53  * systems. Every memory type is described by the struct memblock_type
54  * which contains an array of memory regions along with
55  * the allocator metadata. The "memory" and "reserved" types are nicely
56  * wrapped with struct memblock. This structure is statically
57  * initialized at build time. The region arrays are initially sized to
58  * %INIT_MEMBLOCK_REGIONS for "memory" and %INIT_MEMBLOCK_RESERVED_REGIONS
59  * for "reserved". The region array for "physmem" is initially sized to
60  * %INIT_PHYSMEM_REGIONS.
61  * The memblock_allow_resize() enables automatic resizing of the region
62  * arrays during addition of new regions. This feature should be used
63  * with care so that memory allocated for the region array will not
64  * overlap with areas that should be reserved, for example initrd.
65  *
66  * The early architecture setup should tell memblock what the physical
67  * memory layout is by using memblock_add() or memblock_add_node()
68  * functions. The first function does not assign the region to a NUMA
69  * node and it is appropriate for UMA systems. Yet, it is possible to
70  * use it on NUMA systems as well and assign the region to a NUMA node
71  * later in the setup process using memblock_set_node(). The
72  * memblock_add_node() performs such an assignment directly.
73  *
74  * Once memblock is setup the memory can be allocated using one of the
75  * API variants:
76  *
77  * * memblock_phys_alloc*() - these functions return the **physical**
78  *   address of the allocated memory
79  * * memblock_alloc*() - these functions return the **virtual** address
80  *   of the allocated memory.
81  *
82  * Note, that both API variants use implicit assumptions about allowed
83  * memory ranges and the fallback methods. Consult the documentation
84  * of memblock_alloc_internal() and memblock_alloc_range_nid()
85  * functions for more elaborate description.
86  *
87  * As the system boot progresses, the architecture specific mem_init()
88  * function frees all the memory to the buddy page allocator.
89  *
90  * Unless an architecture enables %CONFIG_ARCH_KEEP_MEMBLOCK, the
91  * memblock data structures (except "physmem") will be discarded after the
92  * system initialization completes.
93  */
94 
95 #ifndef CONFIG_NUMA
96 struct pglist_data __refdata contig_page_data;
97 EXPORT_SYMBOL(contig_page_data);
98 #endif
99 
100 unsigned long max_low_pfn;
101 unsigned long min_low_pfn;
102 unsigned long max_pfn;
103 unsigned long long max_possible_pfn;
104 
105 static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock;
106 static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_RESERVED_REGIONS] __initdata_memblock;
107 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
108 static struct memblock_region memblock_physmem_init_regions[INIT_PHYSMEM_REGIONS];
109 #endif
110 
111 struct memblock memblock __initdata_memblock = {
112 	.memory.regions		= memblock_memory_init_regions,
113 	.memory.cnt		= 1,	/* empty dummy entry */
114 	.memory.max		= INIT_MEMBLOCK_REGIONS,
115 	.memory.name		= "memory",
116 
117 	.reserved.regions	= memblock_reserved_init_regions,
118 	.reserved.cnt		= 1,	/* empty dummy entry */
119 	.reserved.max		= INIT_MEMBLOCK_RESERVED_REGIONS,
120 	.reserved.name		= "reserved",
121 
122 	.bottom_up		= false,
123 	.current_limit		= MEMBLOCK_ALLOC_ANYWHERE,
124 };
125 
126 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
127 struct memblock_type physmem = {
128 	.regions		= memblock_physmem_init_regions,
129 	.cnt			= 1,	/* empty dummy entry */
130 	.max			= INIT_PHYSMEM_REGIONS,
131 	.name			= "physmem",
132 };
133 #endif
134 
135 /*
136  * keep a pointer to &memblock.memory in the text section to use it in
137  * __next_mem_range() and its helpers.
138  *  For architectures that do not keep memblock data after init, this
139  * pointer will be reset to NULL at memblock_discard()
140  */
141 static __refdata struct memblock_type *memblock_memory = &memblock.memory;
142 
143 #define for_each_memblock_type(i, memblock_type, rgn)			\
144 	for (i = 0, rgn = &memblock_type->regions[0];			\
145 	     i < memblock_type->cnt;					\
146 	     i++, rgn = &memblock_type->regions[i])
147 
148 #define memblock_dbg(fmt, ...)						\
149 	do {								\
150 		if (memblock_debug)					\
151 			pr_info(fmt, ##__VA_ARGS__);			\
152 	} while (0)
153 
154 static int memblock_debug __initdata_memblock;
155 static bool system_has_some_mirror __initdata_memblock = false;
156 static int memblock_can_resize __initdata_memblock;
157 static int memblock_memory_in_slab __initdata_memblock = 0;
158 static int memblock_reserved_in_slab __initdata_memblock = 0;
159 
160 static enum memblock_flags __init_memblock choose_memblock_flags(void)
161 {
162 	return system_has_some_mirror ? MEMBLOCK_MIRROR : MEMBLOCK_NONE;
163 }
164 
165 /* adjust *@size so that (@base + *@size) doesn't overflow, return new size */
166 static inline phys_addr_t memblock_cap_size(phys_addr_t base, phys_addr_t *size)
167 {
168 	return *size = min(*size, PHYS_ADDR_MAX - base);
169 }
170 
171 /*
172  * Address comparison utilities
173  */
174 static unsigned long __init_memblock memblock_addrs_overlap(phys_addr_t base1, phys_addr_t size1,
175 				       phys_addr_t base2, phys_addr_t size2)
176 {
177 	return ((base1 < (base2 + size2)) && (base2 < (base1 + size1)));
178 }
179 
180 bool __init_memblock memblock_overlaps_region(struct memblock_type *type,
181 					phys_addr_t base, phys_addr_t size)
182 {
183 	unsigned long i;
184 
185 	memblock_cap_size(base, &size);
186 
187 	for (i = 0; i < type->cnt; i++)
188 		if (memblock_addrs_overlap(base, size, type->regions[i].base,
189 					   type->regions[i].size))
190 			break;
191 	return i < type->cnt;
192 }
193 
194 /**
195  * __memblock_find_range_bottom_up - find free area utility in bottom-up
196  * @start: start of candidate range
197  * @end: end of candidate range, can be %MEMBLOCK_ALLOC_ANYWHERE or
198  *       %MEMBLOCK_ALLOC_ACCESSIBLE
199  * @size: size of free area to find
200  * @align: alignment of free area to find
201  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
202  * @flags: pick from blocks based on memory attributes
203  *
204  * Utility called from memblock_find_in_range_node(), find free area bottom-up.
205  *
206  * Return:
207  * Found address on success, 0 on failure.
208  */
209 static phys_addr_t __init_memblock
210 __memblock_find_range_bottom_up(phys_addr_t start, phys_addr_t end,
211 				phys_addr_t size, phys_addr_t align, int nid,
212 				enum memblock_flags flags)
213 {
214 	phys_addr_t this_start, this_end, cand;
215 	u64 i;
216 
217 	for_each_free_mem_range(i, nid, flags, &this_start, &this_end, NULL) {
218 		this_start = clamp(this_start, start, end);
219 		this_end = clamp(this_end, start, end);
220 
221 		cand = round_up(this_start, align);
222 		if (cand < this_end && this_end - cand >= size)
223 			return cand;
224 	}
225 
226 	return 0;
227 }
228 
229 /**
230  * __memblock_find_range_top_down - find free area utility, in top-down
231  * @start: start of candidate range
232  * @end: end of candidate range, can be %MEMBLOCK_ALLOC_ANYWHERE or
233  *       %MEMBLOCK_ALLOC_ACCESSIBLE
234  * @size: size of free area to find
235  * @align: alignment of free area to find
236  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
237  * @flags: pick from blocks based on memory attributes
238  *
239  * Utility called from memblock_find_in_range_node(), find free area top-down.
240  *
241  * Return:
242  * Found address on success, 0 on failure.
243  */
244 static phys_addr_t __init_memblock
245 __memblock_find_range_top_down(phys_addr_t start, phys_addr_t end,
246 			       phys_addr_t size, phys_addr_t align, int nid,
247 			       enum memblock_flags flags)
248 {
249 	phys_addr_t this_start, this_end, cand;
250 	u64 i;
251 
252 	for_each_free_mem_range_reverse(i, nid, flags, &this_start, &this_end,
253 					NULL) {
254 		this_start = clamp(this_start, start, end);
255 		this_end = clamp(this_end, start, end);
256 
257 		if (this_end < size)
258 			continue;
259 
260 		cand = round_down(this_end - size, align);
261 		if (cand >= this_start)
262 			return cand;
263 	}
264 
265 	return 0;
266 }
267 
268 /**
269  * memblock_find_in_range_node - find free area in given range and node
270  * @size: size of free area to find
271  * @align: alignment of free area to find
272  * @start: start of candidate range
273  * @end: end of candidate range, can be %MEMBLOCK_ALLOC_ANYWHERE or
274  *       %MEMBLOCK_ALLOC_ACCESSIBLE
275  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
276  * @flags: pick from blocks based on memory attributes
277  *
278  * Find @size free area aligned to @align in the specified range and node.
279  *
280  * Return:
281  * Found address on success, 0 on failure.
282  */
283 static phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t size,
284 					phys_addr_t align, phys_addr_t start,
285 					phys_addr_t end, int nid,
286 					enum memblock_flags flags)
287 {
288 	/* pump up @end */
289 	if (end == MEMBLOCK_ALLOC_ACCESSIBLE ||
290 	    end == MEMBLOCK_ALLOC_KASAN)
291 		end = memblock.current_limit;
292 
293 	/* avoid allocating the first page */
294 	start = max_t(phys_addr_t, start, PAGE_SIZE);
295 	end = max(start, end);
296 
297 	if (memblock_bottom_up())
298 		return __memblock_find_range_bottom_up(start, end, size, align,
299 						       nid, flags);
300 	else
301 		return __memblock_find_range_top_down(start, end, size, align,
302 						      nid, flags);
303 }
304 
305 /**
306  * memblock_find_in_range - find free area in given range
307  * @start: start of candidate range
308  * @end: end of candidate range, can be %MEMBLOCK_ALLOC_ANYWHERE or
309  *       %MEMBLOCK_ALLOC_ACCESSIBLE
310  * @size: size of free area to find
311  * @align: alignment of free area to find
312  *
313  * Find @size free area aligned to @align in the specified range.
314  *
315  * Return:
316  * Found address on success, 0 on failure.
317  */
318 phys_addr_t __init_memblock memblock_find_in_range(phys_addr_t start,
319 					phys_addr_t end, phys_addr_t size,
320 					phys_addr_t align)
321 {
322 	phys_addr_t ret;
323 	enum memblock_flags flags = choose_memblock_flags();
324 
325 again:
326 	ret = memblock_find_in_range_node(size, align, start, end,
327 					    NUMA_NO_NODE, flags);
328 
329 	if (!ret && (flags & MEMBLOCK_MIRROR)) {
330 		pr_warn("Could not allocate %pap bytes of mirrored memory\n",
331 			&size);
332 		flags &= ~MEMBLOCK_MIRROR;
333 		goto again;
334 	}
335 
336 	return ret;
337 }
338 
339 static void __init_memblock memblock_remove_region(struct memblock_type *type, unsigned long r)
340 {
341 	type->total_size -= type->regions[r].size;
342 	memmove(&type->regions[r], &type->regions[r + 1],
343 		(type->cnt - (r + 1)) * sizeof(type->regions[r]));
344 	type->cnt--;
345 
346 	/* Special case for empty arrays */
347 	if (type->cnt == 0) {
348 		WARN_ON(type->total_size != 0);
349 		type->cnt = 1;
350 		type->regions[0].base = 0;
351 		type->regions[0].size = 0;
352 		type->regions[0].flags = 0;
353 		memblock_set_region_node(&type->regions[0], MAX_NUMNODES);
354 	}
355 }
356 
357 #ifndef CONFIG_ARCH_KEEP_MEMBLOCK
358 /**
359  * memblock_discard - discard memory and reserved arrays if they were allocated
360  */
361 void __init memblock_discard(void)
362 {
363 	phys_addr_t addr, size;
364 
365 	if (memblock.reserved.regions != memblock_reserved_init_regions) {
366 		addr = __pa(memblock.reserved.regions);
367 		size = PAGE_ALIGN(sizeof(struct memblock_region) *
368 				  memblock.reserved.max);
369 		__memblock_free_late(addr, size);
370 	}
371 
372 	if (memblock.memory.regions != memblock_memory_init_regions) {
373 		addr = __pa(memblock.memory.regions);
374 		size = PAGE_ALIGN(sizeof(struct memblock_region) *
375 				  memblock.memory.max);
376 		__memblock_free_late(addr, size);
377 	}
378 
379 	memblock_memory = NULL;
380 }
381 #endif
382 
383 /**
384  * memblock_double_array - double the size of the memblock regions array
385  * @type: memblock type of the regions array being doubled
386  * @new_area_start: starting address of memory range to avoid overlap with
387  * @new_area_size: size of memory range to avoid overlap with
388  *
389  * Double the size of the @type regions array. If memblock is being used to
390  * allocate memory for a new reserved regions array and there is a previously
391  * allocated memory range [@new_area_start, @new_area_start + @new_area_size]
392  * waiting to be reserved, ensure the memory used by the new array does
393  * not overlap.
394  *
395  * Return:
396  * 0 on success, -1 on failure.
397  */
398 static int __init_memblock memblock_double_array(struct memblock_type *type,
399 						phys_addr_t new_area_start,
400 						phys_addr_t new_area_size)
401 {
402 	struct memblock_region *new_array, *old_array;
403 	phys_addr_t old_alloc_size, new_alloc_size;
404 	phys_addr_t old_size, new_size, addr, new_end;
405 	int use_slab = slab_is_available();
406 	int *in_slab;
407 
408 	/* We don't allow resizing until we know about the reserved regions
409 	 * of memory that aren't suitable for allocation
410 	 */
411 	if (!memblock_can_resize)
412 		return -1;
413 
414 	/* Calculate new doubled size */
415 	old_size = type->max * sizeof(struct memblock_region);
416 	new_size = old_size << 1;
417 	/*
418 	 * We need to allocated new one align to PAGE_SIZE,
419 	 *   so we can free them completely later.
420 	 */
421 	old_alloc_size = PAGE_ALIGN(old_size);
422 	new_alloc_size = PAGE_ALIGN(new_size);
423 
424 	/* Retrieve the slab flag */
425 	if (type == &memblock.memory)
426 		in_slab = &memblock_memory_in_slab;
427 	else
428 		in_slab = &memblock_reserved_in_slab;
429 
430 	/* Try to find some space for it */
431 	if (use_slab) {
432 		new_array = kmalloc(new_size, GFP_KERNEL);
433 		addr = new_array ? __pa(new_array) : 0;
434 	} else {
435 		/* only exclude range when trying to double reserved.regions */
436 		if (type != &memblock.reserved)
437 			new_area_start = new_area_size = 0;
438 
439 		addr = memblock_find_in_range(new_area_start + new_area_size,
440 						memblock.current_limit,
441 						new_alloc_size, PAGE_SIZE);
442 		if (!addr && new_area_size)
443 			addr = memblock_find_in_range(0,
444 				min(new_area_start, memblock.current_limit),
445 				new_alloc_size, PAGE_SIZE);
446 
447 		new_array = addr ? __va(addr) : NULL;
448 	}
449 	if (!addr) {
450 		pr_err("memblock: Failed to double %s array from %ld to %ld entries !\n",
451 		       type->name, type->max, type->max * 2);
452 		return -1;
453 	}
454 
455 	new_end = addr + new_size - 1;
456 	memblock_dbg("memblock: %s is doubled to %ld at [%pa-%pa]",
457 			type->name, type->max * 2, &addr, &new_end);
458 
459 	/*
460 	 * Found space, we now need to move the array over before we add the
461 	 * reserved region since it may be our reserved array itself that is
462 	 * full.
463 	 */
464 	memcpy(new_array, type->regions, old_size);
465 	memset(new_array + type->max, 0, old_size);
466 	old_array = type->regions;
467 	type->regions = new_array;
468 	type->max <<= 1;
469 
470 	/* Free old array. We needn't free it if the array is the static one */
471 	if (*in_slab)
472 		kfree(old_array);
473 	else if (old_array != memblock_memory_init_regions &&
474 		 old_array != memblock_reserved_init_regions)
475 		memblock_free(__pa(old_array), old_alloc_size);
476 
477 	/*
478 	 * Reserve the new array if that comes from the memblock.  Otherwise, we
479 	 * needn't do it
480 	 */
481 	if (!use_slab)
482 		BUG_ON(memblock_reserve(addr, new_alloc_size));
483 
484 	/* Update slab flag */
485 	*in_slab = use_slab;
486 
487 	return 0;
488 }
489 
490 /**
491  * memblock_merge_regions - merge neighboring compatible regions
492  * @type: memblock type to scan
493  *
494  * Scan @type and merge neighboring compatible regions.
495  */
496 static void __init_memblock memblock_merge_regions(struct memblock_type *type)
497 {
498 	int i = 0;
499 
500 	/* cnt never goes below 1 */
501 	while (i < type->cnt - 1) {
502 		struct memblock_region *this = &type->regions[i];
503 		struct memblock_region *next = &type->regions[i + 1];
504 
505 		if (this->base + this->size != next->base ||
506 		    memblock_get_region_node(this) !=
507 		    memblock_get_region_node(next) ||
508 		    this->flags != next->flags) {
509 			BUG_ON(this->base + this->size > next->base);
510 			i++;
511 			continue;
512 		}
513 
514 		this->size += next->size;
515 		/* move forward from next + 1, index of which is i + 2 */
516 		memmove(next, next + 1, (type->cnt - (i + 2)) * sizeof(*next));
517 		type->cnt--;
518 	}
519 }
520 
521 /**
522  * memblock_insert_region - insert new memblock region
523  * @type:	memblock type to insert into
524  * @idx:	index for the insertion point
525  * @base:	base address of the new region
526  * @size:	size of the new region
527  * @nid:	node id of the new region
528  * @flags:	flags of the new region
529  *
530  * Insert new memblock region [@base, @base + @size) into @type at @idx.
531  * @type must already have extra room to accommodate the new region.
532  */
533 static void __init_memblock memblock_insert_region(struct memblock_type *type,
534 						   int idx, phys_addr_t base,
535 						   phys_addr_t size,
536 						   int nid,
537 						   enum memblock_flags flags)
538 {
539 	struct memblock_region *rgn = &type->regions[idx];
540 
541 	BUG_ON(type->cnt >= type->max);
542 	memmove(rgn + 1, rgn, (type->cnt - idx) * sizeof(*rgn));
543 	rgn->base = base;
544 	rgn->size = size;
545 	rgn->flags = flags;
546 	memblock_set_region_node(rgn, nid);
547 	type->cnt++;
548 	type->total_size += size;
549 }
550 
551 /**
552  * memblock_add_range - add new memblock region
553  * @type: memblock type to add new region into
554  * @base: base address of the new region
555  * @size: size of the new region
556  * @nid: nid of the new region
557  * @flags: flags of the new region
558  *
559  * Add new memblock region [@base, @base + @size) into @type.  The new region
560  * is allowed to overlap with existing ones - overlaps don't affect already
561  * existing regions.  @type is guaranteed to be minimal (all neighbouring
562  * compatible regions are merged) after the addition.
563  *
564  * Return:
565  * 0 on success, -errno on failure.
566  */
567 static int __init_memblock memblock_add_range(struct memblock_type *type,
568 				phys_addr_t base, phys_addr_t size,
569 				int nid, enum memblock_flags flags)
570 {
571 	bool insert = false;
572 	phys_addr_t obase = base;
573 	phys_addr_t end = base + memblock_cap_size(base, &size);
574 	int idx, nr_new;
575 	struct memblock_region *rgn;
576 
577 	if (!size)
578 		return 0;
579 
580 	/* special case for empty array */
581 	if (type->regions[0].size == 0) {
582 		WARN_ON(type->cnt != 1 || type->total_size);
583 		type->regions[0].base = base;
584 		type->regions[0].size = size;
585 		type->regions[0].flags = flags;
586 		memblock_set_region_node(&type->regions[0], nid);
587 		type->total_size = size;
588 		return 0;
589 	}
590 repeat:
591 	/*
592 	 * The following is executed twice.  Once with %false @insert and
593 	 * then with %true.  The first counts the number of regions needed
594 	 * to accommodate the new area.  The second actually inserts them.
595 	 */
596 	base = obase;
597 	nr_new = 0;
598 
599 	for_each_memblock_type(idx, type, rgn) {
600 		phys_addr_t rbase = rgn->base;
601 		phys_addr_t rend = rbase + rgn->size;
602 
603 		if (rbase >= end)
604 			break;
605 		if (rend <= base)
606 			continue;
607 		/*
608 		 * @rgn overlaps.  If it separates the lower part of new
609 		 * area, insert that portion.
610 		 */
611 		if (rbase > base) {
612 #ifdef CONFIG_NUMA
613 			WARN_ON(nid != memblock_get_region_node(rgn));
614 #endif
615 			WARN_ON(flags != rgn->flags);
616 			nr_new++;
617 			if (insert)
618 				memblock_insert_region(type, idx++, base,
619 						       rbase - base, nid,
620 						       flags);
621 		}
622 		/* area below @rend is dealt with, forget about it */
623 		base = min(rend, end);
624 	}
625 
626 	/* insert the remaining portion */
627 	if (base < end) {
628 		nr_new++;
629 		if (insert)
630 			memblock_insert_region(type, idx, base, end - base,
631 					       nid, flags);
632 	}
633 
634 	if (!nr_new)
635 		return 0;
636 
637 	/*
638 	 * If this was the first round, resize array and repeat for actual
639 	 * insertions; otherwise, merge and return.
640 	 */
641 	if (!insert) {
642 		while (type->cnt + nr_new > type->max)
643 			if (memblock_double_array(type, obase, size) < 0)
644 				return -ENOMEM;
645 		insert = true;
646 		goto repeat;
647 	} else {
648 		memblock_merge_regions(type);
649 		return 0;
650 	}
651 }
652 
653 /**
654  * memblock_add_node - add new memblock region within a NUMA node
655  * @base: base address of the new region
656  * @size: size of the new region
657  * @nid: nid of the new region
658  *
659  * Add new memblock region [@base, @base + @size) to the "memory"
660  * type. See memblock_add_range() description for mode details
661  *
662  * Return:
663  * 0 on success, -errno on failure.
664  */
665 int __init_memblock memblock_add_node(phys_addr_t base, phys_addr_t size,
666 				       int nid)
667 {
668 	return memblock_add_range(&memblock.memory, base, size, nid, 0);
669 }
670 
671 /**
672  * memblock_add - add new memblock region
673  * @base: base address of the new region
674  * @size: size of the new region
675  *
676  * Add new memblock region [@base, @base + @size) to the "memory"
677  * type. See memblock_add_range() description for mode details
678  *
679  * Return:
680  * 0 on success, -errno on failure.
681  */
682 int __init_memblock memblock_add(phys_addr_t base, phys_addr_t size)
683 {
684 	phys_addr_t end = base + size - 1;
685 
686 	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
687 		     &base, &end, (void *)_RET_IP_);
688 
689 	return memblock_add_range(&memblock.memory, base, size, MAX_NUMNODES, 0);
690 }
691 
692 /**
693  * memblock_isolate_range - isolate given range into disjoint memblocks
694  * @type: memblock type to isolate range for
695  * @base: base of range to isolate
696  * @size: size of range to isolate
697  * @start_rgn: out parameter for the start of isolated region
698  * @end_rgn: out parameter for the end of isolated region
699  *
700  * Walk @type and ensure that regions don't cross the boundaries defined by
701  * [@base, @base + @size).  Crossing regions are split at the boundaries,
702  * which may create at most two more regions.  The index of the first
703  * region inside the range is returned in *@start_rgn and end in *@end_rgn.
704  *
705  * Return:
706  * 0 on success, -errno on failure.
707  */
708 static int __init_memblock memblock_isolate_range(struct memblock_type *type,
709 					phys_addr_t base, phys_addr_t size,
710 					int *start_rgn, int *end_rgn)
711 {
712 	phys_addr_t end = base + memblock_cap_size(base, &size);
713 	int idx;
714 	struct memblock_region *rgn;
715 
716 	*start_rgn = *end_rgn = 0;
717 
718 	if (!size)
719 		return 0;
720 
721 	/* we'll create at most two more regions */
722 	while (type->cnt + 2 > type->max)
723 		if (memblock_double_array(type, base, size) < 0)
724 			return -ENOMEM;
725 
726 	for_each_memblock_type(idx, type, rgn) {
727 		phys_addr_t rbase = rgn->base;
728 		phys_addr_t rend = rbase + rgn->size;
729 
730 		if (rbase >= end)
731 			break;
732 		if (rend <= base)
733 			continue;
734 
735 		if (rbase < base) {
736 			/*
737 			 * @rgn intersects from below.  Split and continue
738 			 * to process the next region - the new top half.
739 			 */
740 			rgn->base = base;
741 			rgn->size -= base - rbase;
742 			type->total_size -= base - rbase;
743 			memblock_insert_region(type, idx, rbase, base - rbase,
744 					       memblock_get_region_node(rgn),
745 					       rgn->flags);
746 		} else if (rend > end) {
747 			/*
748 			 * @rgn intersects from above.  Split and redo the
749 			 * current region - the new bottom half.
750 			 */
751 			rgn->base = end;
752 			rgn->size -= end - rbase;
753 			type->total_size -= end - rbase;
754 			memblock_insert_region(type, idx--, rbase, end - rbase,
755 					       memblock_get_region_node(rgn),
756 					       rgn->flags);
757 		} else {
758 			/* @rgn is fully contained, record it */
759 			if (!*end_rgn)
760 				*start_rgn = idx;
761 			*end_rgn = idx + 1;
762 		}
763 	}
764 
765 	return 0;
766 }
767 
768 static int __init_memblock memblock_remove_range(struct memblock_type *type,
769 					  phys_addr_t base, phys_addr_t size)
770 {
771 	int start_rgn, end_rgn;
772 	int i, ret;
773 
774 	ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
775 	if (ret)
776 		return ret;
777 
778 	for (i = end_rgn - 1; i >= start_rgn; i--)
779 		memblock_remove_region(type, i);
780 	return 0;
781 }
782 
783 int __init_memblock memblock_remove(phys_addr_t base, phys_addr_t size)
784 {
785 	phys_addr_t end = base + size - 1;
786 
787 	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
788 		     &base, &end, (void *)_RET_IP_);
789 
790 	return memblock_remove_range(&memblock.memory, base, size);
791 }
792 
793 /**
794  * memblock_free - free boot memory block
795  * @base: phys starting address of the  boot memory block
796  * @size: size of the boot memory block in bytes
797  *
798  * Free boot memory block previously allocated by memblock_alloc_xx() API.
799  * The freeing memory will not be released to the buddy allocator.
800  */
801 int __init_memblock memblock_free(phys_addr_t base, phys_addr_t size)
802 {
803 	phys_addr_t end = base + size - 1;
804 
805 	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
806 		     &base, &end, (void *)_RET_IP_);
807 
808 	kmemleak_free_part_phys(base, size);
809 	return memblock_remove_range(&memblock.reserved, base, size);
810 }
811 
812 int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
813 {
814 	phys_addr_t end = base + size - 1;
815 
816 	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
817 		     &base, &end, (void *)_RET_IP_);
818 
819 	return memblock_add_range(&memblock.reserved, base, size, MAX_NUMNODES, 0);
820 }
821 
822 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
823 int __init_memblock memblock_physmem_add(phys_addr_t base, phys_addr_t size)
824 {
825 	phys_addr_t end = base + size - 1;
826 
827 	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
828 		     &base, &end, (void *)_RET_IP_);
829 
830 	return memblock_add_range(&physmem, base, size, MAX_NUMNODES, 0);
831 }
832 #endif
833 
834 /**
835  * memblock_setclr_flag - set or clear flag for a memory region
836  * @base: base address of the region
837  * @size: size of the region
838  * @set: set or clear the flag
839  * @flag: the flag to update
840  *
841  * This function isolates region [@base, @base + @size), and sets/clears flag
842  *
843  * Return: 0 on success, -errno on failure.
844  */
845 static int __init_memblock memblock_setclr_flag(phys_addr_t base,
846 				phys_addr_t size, int set, int flag)
847 {
848 	struct memblock_type *type = &memblock.memory;
849 	int i, ret, start_rgn, end_rgn;
850 
851 	ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
852 	if (ret)
853 		return ret;
854 
855 	for (i = start_rgn; i < end_rgn; i++) {
856 		struct memblock_region *r = &type->regions[i];
857 
858 		if (set)
859 			r->flags |= flag;
860 		else
861 			r->flags &= ~flag;
862 	}
863 
864 	memblock_merge_regions(type);
865 	return 0;
866 }
867 
868 /**
869  * memblock_mark_hotplug - Mark hotpluggable memory with flag MEMBLOCK_HOTPLUG.
870  * @base: the base phys addr of the region
871  * @size: the size of the region
872  *
873  * Return: 0 on success, -errno on failure.
874  */
875 int __init_memblock memblock_mark_hotplug(phys_addr_t base, phys_addr_t size)
876 {
877 	return memblock_setclr_flag(base, size, 1, MEMBLOCK_HOTPLUG);
878 }
879 
880 /**
881  * memblock_clear_hotplug - Clear flag MEMBLOCK_HOTPLUG for a specified region.
882  * @base: the base phys addr of the region
883  * @size: the size of the region
884  *
885  * Return: 0 on success, -errno on failure.
886  */
887 int __init_memblock memblock_clear_hotplug(phys_addr_t base, phys_addr_t size)
888 {
889 	return memblock_setclr_flag(base, size, 0, MEMBLOCK_HOTPLUG);
890 }
891 
892 /**
893  * memblock_mark_mirror - Mark mirrored memory with flag MEMBLOCK_MIRROR.
894  * @base: the base phys addr of the region
895  * @size: the size of the region
896  *
897  * Return: 0 on success, -errno on failure.
898  */
899 int __init_memblock memblock_mark_mirror(phys_addr_t base, phys_addr_t size)
900 {
901 	system_has_some_mirror = true;
902 
903 	return memblock_setclr_flag(base, size, 1, MEMBLOCK_MIRROR);
904 }
905 
906 /**
907  * memblock_mark_nomap - Mark a memory region with flag MEMBLOCK_NOMAP.
908  * @base: the base phys addr of the region
909  * @size: the size of the region
910  *
911  * The memory regions marked with %MEMBLOCK_NOMAP will not be added to the
912  * direct mapping of the physical memory. These regions will still be
913  * covered by the memory map. The struct page representing NOMAP memory
914  * frames in the memory map will be PageReserved()
915  *
916  * Return: 0 on success, -errno on failure.
917  */
918 int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size)
919 {
920 	return memblock_setclr_flag(base, size, 1, MEMBLOCK_NOMAP);
921 }
922 
923 /**
924  * memblock_clear_nomap - Clear flag MEMBLOCK_NOMAP for a specified region.
925  * @base: the base phys addr of the region
926  * @size: the size of the region
927  *
928  * Return: 0 on success, -errno on failure.
929  */
930 int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size)
931 {
932 	return memblock_setclr_flag(base, size, 0, MEMBLOCK_NOMAP);
933 }
934 
935 static bool should_skip_region(struct memblock_type *type,
936 			       struct memblock_region *m,
937 			       int nid, int flags)
938 {
939 	int m_nid = memblock_get_region_node(m);
940 
941 	/* we never skip regions when iterating memblock.reserved or physmem */
942 	if (type != memblock_memory)
943 		return false;
944 
945 	/* only memory regions are associated with nodes, check it */
946 	if (nid != NUMA_NO_NODE && nid != m_nid)
947 		return true;
948 
949 	/* skip hotpluggable memory regions if needed */
950 	if (movable_node_is_enabled() && memblock_is_hotpluggable(m) &&
951 	    !(flags & MEMBLOCK_HOTPLUG))
952 		return true;
953 
954 	/* if we want mirror memory skip non-mirror memory regions */
955 	if ((flags & MEMBLOCK_MIRROR) && !memblock_is_mirror(m))
956 		return true;
957 
958 	/* skip nomap memory unless we were asked for it explicitly */
959 	if (!(flags & MEMBLOCK_NOMAP) && memblock_is_nomap(m))
960 		return true;
961 
962 	return false;
963 }
964 
965 /**
966  * __next_mem_range - next function for for_each_free_mem_range() etc.
967  * @idx: pointer to u64 loop variable
968  * @nid: node selector, %NUMA_NO_NODE for all nodes
969  * @flags: pick from blocks based on memory attributes
970  * @type_a: pointer to memblock_type from where the range is taken
971  * @type_b: pointer to memblock_type which excludes memory from being taken
972  * @out_start: ptr to phys_addr_t for start address of the range, can be %NULL
973  * @out_end: ptr to phys_addr_t for end address of the range, can be %NULL
974  * @out_nid: ptr to int for nid of the range, can be %NULL
975  *
976  * Find the first area from *@idx which matches @nid, fill the out
977  * parameters, and update *@idx for the next iteration.  The lower 32bit of
978  * *@idx contains index into type_a and the upper 32bit indexes the
979  * areas before each region in type_b.	For example, if type_b regions
980  * look like the following,
981  *
982  *	0:[0-16), 1:[32-48), 2:[128-130)
983  *
984  * The upper 32bit indexes the following regions.
985  *
986  *	0:[0-0), 1:[16-32), 2:[48-128), 3:[130-MAX)
987  *
988  * As both region arrays are sorted, the function advances the two indices
989  * in lockstep and returns each intersection.
990  */
991 void __next_mem_range(u64 *idx, int nid, enum memblock_flags flags,
992 		      struct memblock_type *type_a,
993 		      struct memblock_type *type_b, phys_addr_t *out_start,
994 		      phys_addr_t *out_end, int *out_nid)
995 {
996 	int idx_a = *idx & 0xffffffff;
997 	int idx_b = *idx >> 32;
998 
999 	if (WARN_ONCE(nid == MAX_NUMNODES,
1000 	"Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
1001 		nid = NUMA_NO_NODE;
1002 
1003 	for (; idx_a < type_a->cnt; idx_a++) {
1004 		struct memblock_region *m = &type_a->regions[idx_a];
1005 
1006 		phys_addr_t m_start = m->base;
1007 		phys_addr_t m_end = m->base + m->size;
1008 		int	    m_nid = memblock_get_region_node(m);
1009 
1010 		if (should_skip_region(type_a, m, nid, flags))
1011 			continue;
1012 
1013 		if (!type_b) {
1014 			if (out_start)
1015 				*out_start = m_start;
1016 			if (out_end)
1017 				*out_end = m_end;
1018 			if (out_nid)
1019 				*out_nid = m_nid;
1020 			idx_a++;
1021 			*idx = (u32)idx_a | (u64)idx_b << 32;
1022 			return;
1023 		}
1024 
1025 		/* scan areas before each reservation */
1026 		for (; idx_b < type_b->cnt + 1; idx_b++) {
1027 			struct memblock_region *r;
1028 			phys_addr_t r_start;
1029 			phys_addr_t r_end;
1030 
1031 			r = &type_b->regions[idx_b];
1032 			r_start = idx_b ? r[-1].base + r[-1].size : 0;
1033 			r_end = idx_b < type_b->cnt ?
1034 				r->base : PHYS_ADDR_MAX;
1035 
1036 			/*
1037 			 * if idx_b advanced past idx_a,
1038 			 * break out to advance idx_a
1039 			 */
1040 			if (r_start >= m_end)
1041 				break;
1042 			/* if the two regions intersect, we're done */
1043 			if (m_start < r_end) {
1044 				if (out_start)
1045 					*out_start =
1046 						max(m_start, r_start);
1047 				if (out_end)
1048 					*out_end = min(m_end, r_end);
1049 				if (out_nid)
1050 					*out_nid = m_nid;
1051 				/*
1052 				 * The region which ends first is
1053 				 * advanced for the next iteration.
1054 				 */
1055 				if (m_end <= r_end)
1056 					idx_a++;
1057 				else
1058 					idx_b++;
1059 				*idx = (u32)idx_a | (u64)idx_b << 32;
1060 				return;
1061 			}
1062 		}
1063 	}
1064 
1065 	/* signal end of iteration */
1066 	*idx = ULLONG_MAX;
1067 }
1068 
1069 /**
1070  * __next_mem_range_rev - generic next function for for_each_*_range_rev()
1071  *
1072  * @idx: pointer to u64 loop variable
1073  * @nid: node selector, %NUMA_NO_NODE for all nodes
1074  * @flags: pick from blocks based on memory attributes
1075  * @type_a: pointer to memblock_type from where the range is taken
1076  * @type_b: pointer to memblock_type which excludes memory from being taken
1077  * @out_start: ptr to phys_addr_t for start address of the range, can be %NULL
1078  * @out_end: ptr to phys_addr_t for end address of the range, can be %NULL
1079  * @out_nid: ptr to int for nid of the range, can be %NULL
1080  *
1081  * Finds the next range from type_a which is not marked as unsuitable
1082  * in type_b.
1083  *
1084  * Reverse of __next_mem_range().
1085  */
1086 void __init_memblock __next_mem_range_rev(u64 *idx, int nid,
1087 					  enum memblock_flags flags,
1088 					  struct memblock_type *type_a,
1089 					  struct memblock_type *type_b,
1090 					  phys_addr_t *out_start,
1091 					  phys_addr_t *out_end, int *out_nid)
1092 {
1093 	int idx_a = *idx & 0xffffffff;
1094 	int idx_b = *idx >> 32;
1095 
1096 	if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
1097 		nid = NUMA_NO_NODE;
1098 
1099 	if (*idx == (u64)ULLONG_MAX) {
1100 		idx_a = type_a->cnt - 1;
1101 		if (type_b != NULL)
1102 			idx_b = type_b->cnt;
1103 		else
1104 			idx_b = 0;
1105 	}
1106 
1107 	for (; idx_a >= 0; idx_a--) {
1108 		struct memblock_region *m = &type_a->regions[idx_a];
1109 
1110 		phys_addr_t m_start = m->base;
1111 		phys_addr_t m_end = m->base + m->size;
1112 		int m_nid = memblock_get_region_node(m);
1113 
1114 		if (should_skip_region(type_a, m, nid, flags))
1115 			continue;
1116 
1117 		if (!type_b) {
1118 			if (out_start)
1119 				*out_start = m_start;
1120 			if (out_end)
1121 				*out_end = m_end;
1122 			if (out_nid)
1123 				*out_nid = m_nid;
1124 			idx_a--;
1125 			*idx = (u32)idx_a | (u64)idx_b << 32;
1126 			return;
1127 		}
1128 
1129 		/* scan areas before each reservation */
1130 		for (; idx_b >= 0; idx_b--) {
1131 			struct memblock_region *r;
1132 			phys_addr_t r_start;
1133 			phys_addr_t r_end;
1134 
1135 			r = &type_b->regions[idx_b];
1136 			r_start = idx_b ? r[-1].base + r[-1].size : 0;
1137 			r_end = idx_b < type_b->cnt ?
1138 				r->base : PHYS_ADDR_MAX;
1139 			/*
1140 			 * if idx_b advanced past idx_a,
1141 			 * break out to advance idx_a
1142 			 */
1143 
1144 			if (r_end <= m_start)
1145 				break;
1146 			/* if the two regions intersect, we're done */
1147 			if (m_end > r_start) {
1148 				if (out_start)
1149 					*out_start = max(m_start, r_start);
1150 				if (out_end)
1151 					*out_end = min(m_end, r_end);
1152 				if (out_nid)
1153 					*out_nid = m_nid;
1154 				if (m_start >= r_start)
1155 					idx_a--;
1156 				else
1157 					idx_b--;
1158 				*idx = (u32)idx_a | (u64)idx_b << 32;
1159 				return;
1160 			}
1161 		}
1162 	}
1163 	/* signal end of iteration */
1164 	*idx = ULLONG_MAX;
1165 }
1166 
1167 /*
1168  * Common iterator interface used to define for_each_mem_pfn_range().
1169  */
1170 void __init_memblock __next_mem_pfn_range(int *idx, int nid,
1171 				unsigned long *out_start_pfn,
1172 				unsigned long *out_end_pfn, int *out_nid)
1173 {
1174 	struct memblock_type *type = &memblock.memory;
1175 	struct memblock_region *r;
1176 	int r_nid;
1177 
1178 	while (++*idx < type->cnt) {
1179 		r = &type->regions[*idx];
1180 		r_nid = memblock_get_region_node(r);
1181 
1182 		if (PFN_UP(r->base) >= PFN_DOWN(r->base + r->size))
1183 			continue;
1184 		if (nid == MAX_NUMNODES || nid == r_nid)
1185 			break;
1186 	}
1187 	if (*idx >= type->cnt) {
1188 		*idx = -1;
1189 		return;
1190 	}
1191 
1192 	if (out_start_pfn)
1193 		*out_start_pfn = PFN_UP(r->base);
1194 	if (out_end_pfn)
1195 		*out_end_pfn = PFN_DOWN(r->base + r->size);
1196 	if (out_nid)
1197 		*out_nid = r_nid;
1198 }
1199 
1200 /**
1201  * memblock_set_node - set node ID on memblock regions
1202  * @base: base of area to set node ID for
1203  * @size: size of area to set node ID for
1204  * @type: memblock type to set node ID for
1205  * @nid: node ID to set
1206  *
1207  * Set the nid of memblock @type regions in [@base, @base + @size) to @nid.
1208  * Regions which cross the area boundaries are split as necessary.
1209  *
1210  * Return:
1211  * 0 on success, -errno on failure.
1212  */
1213 int __init_memblock memblock_set_node(phys_addr_t base, phys_addr_t size,
1214 				      struct memblock_type *type, int nid)
1215 {
1216 #ifdef CONFIG_NUMA
1217 	int start_rgn, end_rgn;
1218 	int i, ret;
1219 
1220 	ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
1221 	if (ret)
1222 		return ret;
1223 
1224 	for (i = start_rgn; i < end_rgn; i++)
1225 		memblock_set_region_node(&type->regions[i], nid);
1226 
1227 	memblock_merge_regions(type);
1228 #endif
1229 	return 0;
1230 }
1231 
1232 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1233 /**
1234  * __next_mem_pfn_range_in_zone - iterator for for_each_*_range_in_zone()
1235  *
1236  * @idx: pointer to u64 loop variable
1237  * @zone: zone in which all of the memory blocks reside
1238  * @out_spfn: ptr to ulong for start pfn of the range, can be %NULL
1239  * @out_epfn: ptr to ulong for end pfn of the range, can be %NULL
1240  *
1241  * This function is meant to be a zone/pfn specific wrapper for the
1242  * for_each_mem_range type iterators. Specifically they are used in the
1243  * deferred memory init routines and as such we were duplicating much of
1244  * this logic throughout the code. So instead of having it in multiple
1245  * locations it seemed like it would make more sense to centralize this to
1246  * one new iterator that does everything they need.
1247  */
1248 void __init_memblock
1249 __next_mem_pfn_range_in_zone(u64 *idx, struct zone *zone,
1250 			     unsigned long *out_spfn, unsigned long *out_epfn)
1251 {
1252 	int zone_nid = zone_to_nid(zone);
1253 	phys_addr_t spa, epa;
1254 	int nid;
1255 
1256 	__next_mem_range(idx, zone_nid, MEMBLOCK_NONE,
1257 			 &memblock.memory, &memblock.reserved,
1258 			 &spa, &epa, &nid);
1259 
1260 	while (*idx != U64_MAX) {
1261 		unsigned long epfn = PFN_DOWN(epa);
1262 		unsigned long spfn = PFN_UP(spa);
1263 
1264 		/*
1265 		 * Verify the end is at least past the start of the zone and
1266 		 * that we have at least one PFN to initialize.
1267 		 */
1268 		if (zone->zone_start_pfn < epfn && spfn < epfn) {
1269 			/* if we went too far just stop searching */
1270 			if (zone_end_pfn(zone) <= spfn) {
1271 				*idx = U64_MAX;
1272 				break;
1273 			}
1274 
1275 			if (out_spfn)
1276 				*out_spfn = max(zone->zone_start_pfn, spfn);
1277 			if (out_epfn)
1278 				*out_epfn = min(zone_end_pfn(zone), epfn);
1279 
1280 			return;
1281 		}
1282 
1283 		__next_mem_range(idx, zone_nid, MEMBLOCK_NONE,
1284 				 &memblock.memory, &memblock.reserved,
1285 				 &spa, &epa, &nid);
1286 	}
1287 
1288 	/* signal end of iteration */
1289 	if (out_spfn)
1290 		*out_spfn = ULONG_MAX;
1291 	if (out_epfn)
1292 		*out_epfn = 0;
1293 }
1294 
1295 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1296 
1297 /**
1298  * memblock_alloc_range_nid - allocate boot memory block
1299  * @size: size of memory block to be allocated in bytes
1300  * @align: alignment of the region and block's size
1301  * @start: the lower bound of the memory region to allocate (phys address)
1302  * @end: the upper bound of the memory region to allocate (phys address)
1303  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1304  * @exact_nid: control the allocation fall back to other nodes
1305  *
1306  * The allocation is performed from memory region limited by
1307  * memblock.current_limit if @end == %MEMBLOCK_ALLOC_ACCESSIBLE.
1308  *
1309  * If the specified node can not hold the requested memory and @exact_nid
1310  * is false, the allocation falls back to any node in the system.
1311  *
1312  * For systems with memory mirroring, the allocation is attempted first
1313  * from the regions with mirroring enabled and then retried from any
1314  * memory region.
1315  *
1316  * In addition, function sets the min_count to 0 using kmemleak_alloc_phys for
1317  * allocated boot memory block, so that it is never reported as leaks.
1318  *
1319  * Return:
1320  * Physical address of allocated memory block on success, %0 on failure.
1321  */
1322 phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
1323 					phys_addr_t align, phys_addr_t start,
1324 					phys_addr_t end, int nid,
1325 					bool exact_nid)
1326 {
1327 	enum memblock_flags flags = choose_memblock_flags();
1328 	phys_addr_t found;
1329 
1330 	if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
1331 		nid = NUMA_NO_NODE;
1332 
1333 	if (!align) {
1334 		/* Can't use WARNs this early in boot on powerpc */
1335 		dump_stack();
1336 		align = SMP_CACHE_BYTES;
1337 	}
1338 
1339 again:
1340 	found = memblock_find_in_range_node(size, align, start, end, nid,
1341 					    flags);
1342 	if (found && !memblock_reserve(found, size))
1343 		goto done;
1344 
1345 	if (nid != NUMA_NO_NODE && !exact_nid) {
1346 		found = memblock_find_in_range_node(size, align, start,
1347 						    end, NUMA_NO_NODE,
1348 						    flags);
1349 		if (found && !memblock_reserve(found, size))
1350 			goto done;
1351 	}
1352 
1353 	if (flags & MEMBLOCK_MIRROR) {
1354 		flags &= ~MEMBLOCK_MIRROR;
1355 		pr_warn("Could not allocate %pap bytes of mirrored memory\n",
1356 			&size);
1357 		goto again;
1358 	}
1359 
1360 	return 0;
1361 
1362 done:
1363 	/* Skip kmemleak for kasan_init() due to high volume. */
1364 	if (end != MEMBLOCK_ALLOC_KASAN)
1365 		/*
1366 		 * The min_count is set to 0 so that memblock allocated
1367 		 * blocks are never reported as leaks. This is because many
1368 		 * of these blocks are only referred via the physical
1369 		 * address which is not looked up by kmemleak.
1370 		 */
1371 		kmemleak_alloc_phys(found, size, 0, 0);
1372 
1373 	return found;
1374 }
1375 
1376 /**
1377  * memblock_phys_alloc_range - allocate a memory block inside specified range
1378  * @size: size of memory block to be allocated in bytes
1379  * @align: alignment of the region and block's size
1380  * @start: the lower bound of the memory region to allocate (physical address)
1381  * @end: the upper bound of the memory region to allocate (physical address)
1382  *
1383  * Allocate @size bytes in the between @start and @end.
1384  *
1385  * Return: physical address of the allocated memory block on success,
1386  * %0 on failure.
1387  */
1388 phys_addr_t __init memblock_phys_alloc_range(phys_addr_t size,
1389 					     phys_addr_t align,
1390 					     phys_addr_t start,
1391 					     phys_addr_t end)
1392 {
1393 	memblock_dbg("%s: %llu bytes align=0x%llx from=%pa max_addr=%pa %pS\n",
1394 		     __func__, (u64)size, (u64)align, &start, &end,
1395 		     (void *)_RET_IP_);
1396 	return memblock_alloc_range_nid(size, align, start, end, NUMA_NO_NODE,
1397 					false);
1398 }
1399 
1400 /**
1401  * memblock_phys_alloc_try_nid - allocate a memory block from specified NUMA node
1402  * @size: size of memory block to be allocated in bytes
1403  * @align: alignment of the region and block's size
1404  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1405  *
1406  * Allocates memory block from the specified NUMA node. If the node
1407  * has no available memory, attempts to allocated from any node in the
1408  * system.
1409  *
1410  * Return: physical address of the allocated memory block on success,
1411  * %0 on failure.
1412  */
1413 phys_addr_t __init memblock_phys_alloc_try_nid(phys_addr_t size, phys_addr_t align, int nid)
1414 {
1415 	return memblock_alloc_range_nid(size, align, 0,
1416 					MEMBLOCK_ALLOC_ACCESSIBLE, nid, false);
1417 }
1418 
1419 /**
1420  * memblock_alloc_internal - allocate boot memory block
1421  * @size: size of memory block to be allocated in bytes
1422  * @align: alignment of the region and block's size
1423  * @min_addr: the lower bound of the memory region to allocate (phys address)
1424  * @max_addr: the upper bound of the memory region to allocate (phys address)
1425  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1426  * @exact_nid: control the allocation fall back to other nodes
1427  *
1428  * Allocates memory block using memblock_alloc_range_nid() and
1429  * converts the returned physical address to virtual.
1430  *
1431  * The @min_addr limit is dropped if it can not be satisfied and the allocation
1432  * will fall back to memory below @min_addr. Other constraints, such
1433  * as node and mirrored memory will be handled again in
1434  * memblock_alloc_range_nid().
1435  *
1436  * Return:
1437  * Virtual address of allocated memory block on success, NULL on failure.
1438  */
1439 static void * __init memblock_alloc_internal(
1440 				phys_addr_t size, phys_addr_t align,
1441 				phys_addr_t min_addr, phys_addr_t max_addr,
1442 				int nid, bool exact_nid)
1443 {
1444 	phys_addr_t alloc;
1445 
1446 	/*
1447 	 * Detect any accidental use of these APIs after slab is ready, as at
1448 	 * this moment memblock may be deinitialized already and its
1449 	 * internal data may be destroyed (after execution of memblock_free_all)
1450 	 */
1451 	if (WARN_ON_ONCE(slab_is_available()))
1452 		return kzalloc_node(size, GFP_NOWAIT, nid);
1453 
1454 	if (max_addr > memblock.current_limit)
1455 		max_addr = memblock.current_limit;
1456 
1457 	alloc = memblock_alloc_range_nid(size, align, min_addr, max_addr, nid,
1458 					exact_nid);
1459 
1460 	/* retry allocation without lower limit */
1461 	if (!alloc && min_addr)
1462 		alloc = memblock_alloc_range_nid(size, align, 0, max_addr, nid,
1463 						exact_nid);
1464 
1465 	if (!alloc)
1466 		return NULL;
1467 
1468 	return phys_to_virt(alloc);
1469 }
1470 
1471 /**
1472  * memblock_alloc_exact_nid_raw - allocate boot memory block on the exact node
1473  * without zeroing memory
1474  * @size: size of memory block to be allocated in bytes
1475  * @align: alignment of the region and block's size
1476  * @min_addr: the lower bound of the memory region from where the allocation
1477  *	  is preferred (phys address)
1478  * @max_addr: the upper bound of the memory region from where the allocation
1479  *	      is preferred (phys address), or %MEMBLOCK_ALLOC_ACCESSIBLE to
1480  *	      allocate only from memory limited by memblock.current_limit value
1481  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1482  *
1483  * Public function, provides additional debug information (including caller
1484  * info), if enabled. Does not zero allocated memory.
1485  *
1486  * Return:
1487  * Virtual address of allocated memory block on success, NULL on failure.
1488  */
1489 void * __init memblock_alloc_exact_nid_raw(
1490 			phys_addr_t size, phys_addr_t align,
1491 			phys_addr_t min_addr, phys_addr_t max_addr,
1492 			int nid)
1493 {
1494 	void *ptr;
1495 
1496 	memblock_dbg("%s: %llu bytes align=0x%llx nid=%d from=%pa max_addr=%pa %pS\n",
1497 		     __func__, (u64)size, (u64)align, nid, &min_addr,
1498 		     &max_addr, (void *)_RET_IP_);
1499 
1500 	ptr = memblock_alloc_internal(size, align,
1501 					   min_addr, max_addr, nid, true);
1502 	if (ptr && size > 0)
1503 		page_init_poison(ptr, size);
1504 
1505 	return ptr;
1506 }
1507 
1508 /**
1509  * memblock_alloc_try_nid_raw - allocate boot memory block without zeroing
1510  * memory and without panicking
1511  * @size: size of memory block to be allocated in bytes
1512  * @align: alignment of the region and block's size
1513  * @min_addr: the lower bound of the memory region from where the allocation
1514  *	  is preferred (phys address)
1515  * @max_addr: the upper bound of the memory region from where the allocation
1516  *	      is preferred (phys address), or %MEMBLOCK_ALLOC_ACCESSIBLE to
1517  *	      allocate only from memory limited by memblock.current_limit value
1518  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1519  *
1520  * Public function, provides additional debug information (including caller
1521  * info), if enabled. Does not zero allocated memory, does not panic if request
1522  * cannot be satisfied.
1523  *
1524  * Return:
1525  * Virtual address of allocated memory block on success, NULL on failure.
1526  */
1527 void * __init memblock_alloc_try_nid_raw(
1528 			phys_addr_t size, phys_addr_t align,
1529 			phys_addr_t min_addr, phys_addr_t max_addr,
1530 			int nid)
1531 {
1532 	void *ptr;
1533 
1534 	memblock_dbg("%s: %llu bytes align=0x%llx nid=%d from=%pa max_addr=%pa %pS\n",
1535 		     __func__, (u64)size, (u64)align, nid, &min_addr,
1536 		     &max_addr, (void *)_RET_IP_);
1537 
1538 	ptr = memblock_alloc_internal(size, align,
1539 					   min_addr, max_addr, nid, false);
1540 	if (ptr && size > 0)
1541 		page_init_poison(ptr, size);
1542 
1543 	return ptr;
1544 }
1545 
1546 /**
1547  * memblock_alloc_try_nid - allocate boot memory block
1548  * @size: size of memory block to be allocated in bytes
1549  * @align: alignment of the region and block's size
1550  * @min_addr: the lower bound of the memory region from where the allocation
1551  *	  is preferred (phys address)
1552  * @max_addr: the upper bound of the memory region from where the allocation
1553  *	      is preferred (phys address), or %MEMBLOCK_ALLOC_ACCESSIBLE to
1554  *	      allocate only from memory limited by memblock.current_limit value
1555  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1556  *
1557  * Public function, provides additional debug information (including caller
1558  * info), if enabled. This function zeroes the allocated memory.
1559  *
1560  * Return:
1561  * Virtual address of allocated memory block on success, NULL on failure.
1562  */
1563 void * __init memblock_alloc_try_nid(
1564 			phys_addr_t size, phys_addr_t align,
1565 			phys_addr_t min_addr, phys_addr_t max_addr,
1566 			int nid)
1567 {
1568 	void *ptr;
1569 
1570 	memblock_dbg("%s: %llu bytes align=0x%llx nid=%d from=%pa max_addr=%pa %pS\n",
1571 		     __func__, (u64)size, (u64)align, nid, &min_addr,
1572 		     &max_addr, (void *)_RET_IP_);
1573 	ptr = memblock_alloc_internal(size, align,
1574 					   min_addr, max_addr, nid, false);
1575 	if (ptr)
1576 		memset(ptr, 0, size);
1577 
1578 	return ptr;
1579 }
1580 
1581 /**
1582  * __memblock_free_late - free pages directly to buddy allocator
1583  * @base: phys starting address of the  boot memory block
1584  * @size: size of the boot memory block in bytes
1585  *
1586  * This is only useful when the memblock allocator has already been torn
1587  * down, but we are still initializing the system.  Pages are released directly
1588  * to the buddy allocator.
1589  */
1590 void __init __memblock_free_late(phys_addr_t base, phys_addr_t size)
1591 {
1592 	phys_addr_t cursor, end;
1593 
1594 	end = base + size - 1;
1595 	memblock_dbg("%s: [%pa-%pa] %pS\n",
1596 		     __func__, &base, &end, (void *)_RET_IP_);
1597 	kmemleak_free_part_phys(base, size);
1598 	cursor = PFN_UP(base);
1599 	end = PFN_DOWN(base + size);
1600 
1601 	for (; cursor < end; cursor++) {
1602 		memblock_free_pages(pfn_to_page(cursor), cursor, 0);
1603 		totalram_pages_inc();
1604 	}
1605 }
1606 
1607 /*
1608  * Remaining API functions
1609  */
1610 
1611 phys_addr_t __init_memblock memblock_phys_mem_size(void)
1612 {
1613 	return memblock.memory.total_size;
1614 }
1615 
1616 phys_addr_t __init_memblock memblock_reserved_size(void)
1617 {
1618 	return memblock.reserved.total_size;
1619 }
1620 
1621 /* lowest address */
1622 phys_addr_t __init_memblock memblock_start_of_DRAM(void)
1623 {
1624 	return memblock.memory.regions[0].base;
1625 }
1626 
1627 phys_addr_t __init_memblock memblock_end_of_DRAM(void)
1628 {
1629 	int idx = memblock.memory.cnt - 1;
1630 
1631 	return (memblock.memory.regions[idx].base + memblock.memory.regions[idx].size);
1632 }
1633 
1634 static phys_addr_t __init_memblock __find_max_addr(phys_addr_t limit)
1635 {
1636 	phys_addr_t max_addr = PHYS_ADDR_MAX;
1637 	struct memblock_region *r;
1638 
1639 	/*
1640 	 * translate the memory @limit size into the max address within one of
1641 	 * the memory memblock regions, if the @limit exceeds the total size
1642 	 * of those regions, max_addr will keep original value PHYS_ADDR_MAX
1643 	 */
1644 	for_each_mem_region(r) {
1645 		if (limit <= r->size) {
1646 			max_addr = r->base + limit;
1647 			break;
1648 		}
1649 		limit -= r->size;
1650 	}
1651 
1652 	return max_addr;
1653 }
1654 
1655 void __init memblock_enforce_memory_limit(phys_addr_t limit)
1656 {
1657 	phys_addr_t max_addr;
1658 
1659 	if (!limit)
1660 		return;
1661 
1662 	max_addr = __find_max_addr(limit);
1663 
1664 	/* @limit exceeds the total size of the memory, do nothing */
1665 	if (max_addr == PHYS_ADDR_MAX)
1666 		return;
1667 
1668 	/* truncate both memory and reserved regions */
1669 	memblock_remove_range(&memblock.memory, max_addr,
1670 			      PHYS_ADDR_MAX);
1671 	memblock_remove_range(&memblock.reserved, max_addr,
1672 			      PHYS_ADDR_MAX);
1673 }
1674 
1675 void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size)
1676 {
1677 	int start_rgn, end_rgn;
1678 	int i, ret;
1679 
1680 	if (!size)
1681 		return;
1682 
1683 	ret = memblock_isolate_range(&memblock.memory, base, size,
1684 						&start_rgn, &end_rgn);
1685 	if (ret)
1686 		return;
1687 
1688 	/* remove all the MAP regions */
1689 	for (i = memblock.memory.cnt - 1; i >= end_rgn; i--)
1690 		if (!memblock_is_nomap(&memblock.memory.regions[i]))
1691 			memblock_remove_region(&memblock.memory, i);
1692 
1693 	for (i = start_rgn - 1; i >= 0; i--)
1694 		if (!memblock_is_nomap(&memblock.memory.regions[i]))
1695 			memblock_remove_region(&memblock.memory, i);
1696 
1697 	/* truncate the reserved regions */
1698 	memblock_remove_range(&memblock.reserved, 0, base);
1699 	memblock_remove_range(&memblock.reserved,
1700 			base + size, PHYS_ADDR_MAX);
1701 }
1702 
1703 void __init memblock_mem_limit_remove_map(phys_addr_t limit)
1704 {
1705 	phys_addr_t max_addr;
1706 
1707 	if (!limit)
1708 		return;
1709 
1710 	max_addr = __find_max_addr(limit);
1711 
1712 	/* @limit exceeds the total size of the memory, do nothing */
1713 	if (max_addr == PHYS_ADDR_MAX)
1714 		return;
1715 
1716 	memblock_cap_memory_range(0, max_addr);
1717 }
1718 
1719 static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr)
1720 {
1721 	unsigned int left = 0, right = type->cnt;
1722 
1723 	do {
1724 		unsigned int mid = (right + left) / 2;
1725 
1726 		if (addr < type->regions[mid].base)
1727 			right = mid;
1728 		else if (addr >= (type->regions[mid].base +
1729 				  type->regions[mid].size))
1730 			left = mid + 1;
1731 		else
1732 			return mid;
1733 	} while (left < right);
1734 	return -1;
1735 }
1736 
1737 bool __init_memblock memblock_is_reserved(phys_addr_t addr)
1738 {
1739 	return memblock_search(&memblock.reserved, addr) != -1;
1740 }
1741 
1742 bool __init_memblock memblock_is_memory(phys_addr_t addr)
1743 {
1744 	return memblock_search(&memblock.memory, addr) != -1;
1745 }
1746 
1747 bool __init_memblock memblock_is_map_memory(phys_addr_t addr)
1748 {
1749 	int i = memblock_search(&memblock.memory, addr);
1750 
1751 	if (i == -1)
1752 		return false;
1753 	return !memblock_is_nomap(&memblock.memory.regions[i]);
1754 }
1755 
1756 int __init_memblock memblock_search_pfn_nid(unsigned long pfn,
1757 			 unsigned long *start_pfn, unsigned long *end_pfn)
1758 {
1759 	struct memblock_type *type = &memblock.memory;
1760 	int mid = memblock_search(type, PFN_PHYS(pfn));
1761 
1762 	if (mid == -1)
1763 		return -1;
1764 
1765 	*start_pfn = PFN_DOWN(type->regions[mid].base);
1766 	*end_pfn = PFN_DOWN(type->regions[mid].base + type->regions[mid].size);
1767 
1768 	return memblock_get_region_node(&type->regions[mid]);
1769 }
1770 
1771 /**
1772  * memblock_is_region_memory - check if a region is a subset of memory
1773  * @base: base of region to check
1774  * @size: size of region to check
1775  *
1776  * Check if the region [@base, @base + @size) is a subset of a memory block.
1777  *
1778  * Return:
1779  * 0 if false, non-zero if true
1780  */
1781 bool __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size)
1782 {
1783 	int idx = memblock_search(&memblock.memory, base);
1784 	phys_addr_t end = base + memblock_cap_size(base, &size);
1785 
1786 	if (idx == -1)
1787 		return false;
1788 	return (memblock.memory.regions[idx].base +
1789 		 memblock.memory.regions[idx].size) >= end;
1790 }
1791 
1792 /**
1793  * memblock_is_region_reserved - check if a region intersects reserved memory
1794  * @base: base of region to check
1795  * @size: size of region to check
1796  *
1797  * Check if the region [@base, @base + @size) intersects a reserved
1798  * memory block.
1799  *
1800  * Return:
1801  * True if they intersect, false if not.
1802  */
1803 bool __init_memblock memblock_is_region_reserved(phys_addr_t base, phys_addr_t size)
1804 {
1805 	return memblock_overlaps_region(&memblock.reserved, base, size);
1806 }
1807 
1808 void __init_memblock memblock_trim_memory(phys_addr_t align)
1809 {
1810 	phys_addr_t start, end, orig_start, orig_end;
1811 	struct memblock_region *r;
1812 
1813 	for_each_mem_region(r) {
1814 		orig_start = r->base;
1815 		orig_end = r->base + r->size;
1816 		start = round_up(orig_start, align);
1817 		end = round_down(orig_end, align);
1818 
1819 		if (start == orig_start && end == orig_end)
1820 			continue;
1821 
1822 		if (start < end) {
1823 			r->base = start;
1824 			r->size = end - start;
1825 		} else {
1826 			memblock_remove_region(&memblock.memory,
1827 					       r - memblock.memory.regions);
1828 			r--;
1829 		}
1830 	}
1831 }
1832 
1833 void __init_memblock memblock_set_current_limit(phys_addr_t limit)
1834 {
1835 	memblock.current_limit = limit;
1836 }
1837 
1838 phys_addr_t __init_memblock memblock_get_current_limit(void)
1839 {
1840 	return memblock.current_limit;
1841 }
1842 
1843 static void __init_memblock memblock_dump(struct memblock_type *type)
1844 {
1845 	phys_addr_t base, end, size;
1846 	enum memblock_flags flags;
1847 	int idx;
1848 	struct memblock_region *rgn;
1849 
1850 	pr_info(" %s.cnt  = 0x%lx\n", type->name, type->cnt);
1851 
1852 	for_each_memblock_type(idx, type, rgn) {
1853 		char nid_buf[32] = "";
1854 
1855 		base = rgn->base;
1856 		size = rgn->size;
1857 		end = base + size - 1;
1858 		flags = rgn->flags;
1859 #ifdef CONFIG_NUMA
1860 		if (memblock_get_region_node(rgn) != MAX_NUMNODES)
1861 			snprintf(nid_buf, sizeof(nid_buf), " on node %d",
1862 				 memblock_get_region_node(rgn));
1863 #endif
1864 		pr_info(" %s[%#x]\t[%pa-%pa], %pa bytes%s flags: %#x\n",
1865 			type->name, idx, &base, &end, &size, nid_buf, flags);
1866 	}
1867 }
1868 
1869 static void __init_memblock __memblock_dump_all(void)
1870 {
1871 	pr_info("MEMBLOCK configuration:\n");
1872 	pr_info(" memory size = %pa reserved size = %pa\n",
1873 		&memblock.memory.total_size,
1874 		&memblock.reserved.total_size);
1875 
1876 	memblock_dump(&memblock.memory);
1877 	memblock_dump(&memblock.reserved);
1878 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
1879 	memblock_dump(&physmem);
1880 #endif
1881 }
1882 
1883 void __init_memblock memblock_dump_all(void)
1884 {
1885 	if (memblock_debug)
1886 		__memblock_dump_all();
1887 }
1888 
1889 void __init memblock_allow_resize(void)
1890 {
1891 	memblock_can_resize = 1;
1892 }
1893 
1894 static int __init early_memblock(char *p)
1895 {
1896 	if (p && strstr(p, "debug"))
1897 		memblock_debug = 1;
1898 	return 0;
1899 }
1900 early_param("memblock", early_memblock);
1901 
1902 static void __init free_memmap(unsigned long start_pfn, unsigned long end_pfn)
1903 {
1904 	struct page *start_pg, *end_pg;
1905 	phys_addr_t pg, pgend;
1906 
1907 	/*
1908 	 * Convert start_pfn/end_pfn to a struct page pointer.
1909 	 */
1910 	start_pg = pfn_to_page(start_pfn - 1) + 1;
1911 	end_pg = pfn_to_page(end_pfn - 1) + 1;
1912 
1913 	/*
1914 	 * Convert to physical addresses, and round start upwards and end
1915 	 * downwards.
1916 	 */
1917 	pg = PAGE_ALIGN(__pa(start_pg));
1918 	pgend = __pa(end_pg) & PAGE_MASK;
1919 
1920 	/*
1921 	 * If there are free pages between these, free the section of the
1922 	 * memmap array.
1923 	 */
1924 	if (pg < pgend)
1925 		memblock_free(pg, pgend - pg);
1926 }
1927 
1928 /*
1929  * The mem_map array can get very big.  Free the unused area of the memory map.
1930  */
1931 static void __init free_unused_memmap(void)
1932 {
1933 	unsigned long start, end, prev_end = 0;
1934 	int i;
1935 
1936 	if (!IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) ||
1937 	    IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
1938 		return;
1939 
1940 	/*
1941 	 * This relies on each bank being in address order.
1942 	 * The banks are sorted previously in bootmem_init().
1943 	 */
1944 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, NULL) {
1945 #ifdef CONFIG_SPARSEMEM
1946 		/*
1947 		 * Take care not to free memmap entries that don't exist
1948 		 * due to SPARSEMEM sections which aren't present.
1949 		 */
1950 		start = min(start, ALIGN(prev_end, PAGES_PER_SECTION));
1951 #endif
1952 		/*
1953 		 * Align down here since many operations in VM subsystem
1954 		 * presume that there are no holes in the memory map inside
1955 		 * a pageblock
1956 		 */
1957 		start = round_down(start, pageblock_nr_pages);
1958 
1959 		/*
1960 		 * If we had a previous bank, and there is a space
1961 		 * between the current bank and the previous, free it.
1962 		 */
1963 		if (prev_end && prev_end < start)
1964 			free_memmap(prev_end, start);
1965 
1966 		/*
1967 		 * Align up here since many operations in VM subsystem
1968 		 * presume that there are no holes in the memory map inside
1969 		 * a pageblock
1970 		 */
1971 		prev_end = ALIGN(end, pageblock_nr_pages);
1972 	}
1973 
1974 #ifdef CONFIG_SPARSEMEM
1975 	if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION)) {
1976 		prev_end = ALIGN(end, pageblock_nr_pages);
1977 		free_memmap(prev_end, ALIGN(prev_end, PAGES_PER_SECTION));
1978 	}
1979 #endif
1980 }
1981 
1982 static void __init __free_pages_memory(unsigned long start, unsigned long end)
1983 {
1984 	int order;
1985 
1986 	while (start < end) {
1987 		order = min(MAX_ORDER - 1UL, __ffs(start));
1988 
1989 		while (start + (1UL << order) > end)
1990 			order--;
1991 
1992 		memblock_free_pages(pfn_to_page(start), start, order);
1993 
1994 		start += (1UL << order);
1995 	}
1996 }
1997 
1998 static unsigned long __init __free_memory_core(phys_addr_t start,
1999 				 phys_addr_t end)
2000 {
2001 	unsigned long start_pfn = PFN_UP(start);
2002 	unsigned long end_pfn = min_t(unsigned long,
2003 				      PFN_DOWN(end), max_low_pfn);
2004 
2005 	if (start_pfn >= end_pfn)
2006 		return 0;
2007 
2008 	__free_pages_memory(start_pfn, end_pfn);
2009 
2010 	return end_pfn - start_pfn;
2011 }
2012 
2013 static void __init memmap_init_reserved_pages(void)
2014 {
2015 	struct memblock_region *region;
2016 	phys_addr_t start, end;
2017 	u64 i;
2018 
2019 	/* initialize struct pages for the reserved regions */
2020 	for_each_reserved_mem_range(i, &start, &end)
2021 		reserve_bootmem_region(start, end);
2022 
2023 	/* and also treat struct pages for the NOMAP regions as PageReserved */
2024 	for_each_mem_region(region) {
2025 		if (memblock_is_nomap(region)) {
2026 			start = region->base;
2027 			end = start + region->size;
2028 			reserve_bootmem_region(start, end);
2029 		}
2030 	}
2031 }
2032 
2033 static unsigned long __init free_low_memory_core_early(void)
2034 {
2035 	unsigned long count = 0;
2036 	phys_addr_t start, end;
2037 	u64 i;
2038 
2039 	memblock_clear_hotplug(0, -1);
2040 
2041 	memmap_init_reserved_pages();
2042 
2043 	/*
2044 	 * We need to use NUMA_NO_NODE instead of NODE_DATA(0)->node_id
2045 	 *  because in some case like Node0 doesn't have RAM installed
2046 	 *  low ram will be on Node1
2047 	 */
2048 	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end,
2049 				NULL)
2050 		count += __free_memory_core(start, end);
2051 
2052 	return count;
2053 }
2054 
2055 static int reset_managed_pages_done __initdata;
2056 
2057 void reset_node_managed_pages(pg_data_t *pgdat)
2058 {
2059 	struct zone *z;
2060 
2061 	for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
2062 		atomic_long_set(&z->managed_pages, 0);
2063 }
2064 
2065 void __init reset_all_zones_managed_pages(void)
2066 {
2067 	struct pglist_data *pgdat;
2068 
2069 	if (reset_managed_pages_done)
2070 		return;
2071 
2072 	for_each_online_pgdat(pgdat)
2073 		reset_node_managed_pages(pgdat);
2074 
2075 	reset_managed_pages_done = 1;
2076 }
2077 
2078 /**
2079  * memblock_free_all - release free pages to the buddy allocator
2080  */
2081 void __init memblock_free_all(void)
2082 {
2083 	unsigned long pages;
2084 
2085 	free_unused_memmap();
2086 	reset_all_zones_managed_pages();
2087 
2088 	pages = free_low_memory_core_early();
2089 	totalram_pages_add(pages);
2090 }
2091 
2092 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_ARCH_KEEP_MEMBLOCK)
2093 
2094 static int memblock_debug_show(struct seq_file *m, void *private)
2095 {
2096 	struct memblock_type *type = m->private;
2097 	struct memblock_region *reg;
2098 	int i;
2099 	phys_addr_t end;
2100 
2101 	for (i = 0; i < type->cnt; i++) {
2102 		reg = &type->regions[i];
2103 		end = reg->base + reg->size - 1;
2104 
2105 		seq_printf(m, "%4d: ", i);
2106 		seq_printf(m, "%pa..%pa\n", &reg->base, &end);
2107 	}
2108 	return 0;
2109 }
2110 DEFINE_SHOW_ATTRIBUTE(memblock_debug);
2111 
2112 static int __init memblock_init_debugfs(void)
2113 {
2114 	struct dentry *root = debugfs_create_dir("memblock", NULL);
2115 
2116 	debugfs_create_file("memory", 0444, root,
2117 			    &memblock.memory, &memblock_debug_fops);
2118 	debugfs_create_file("reserved", 0444, root,
2119 			    &memblock.reserved, &memblock_debug_fops);
2120 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
2121 	debugfs_create_file("physmem", 0444, root, &physmem,
2122 			    &memblock_debug_fops);
2123 #endif
2124 
2125 	return 0;
2126 }
2127 __initcall(memblock_init_debugfs);
2128 
2129 #endif /* CONFIG_DEBUG_FS */
2130