xref: /openbmc/linux/mm/memblock.c (revision b38269ec)
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 static 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 	phys_addr_t end = base + size - 1;
669 
670 	memblock_dbg("%s: [%pa-%pa] nid=%d %pS\n", __func__,
671 		     &base, &end, nid, (void *)_RET_IP_);
672 
673 	return memblock_add_range(&memblock.memory, base, size, nid, 0);
674 }
675 
676 /**
677  * memblock_add - add new memblock region
678  * @base: base address of the new region
679  * @size: size of the new region
680  *
681  * Add new memblock region [@base, @base + @size) to the "memory"
682  * type. See memblock_add_range() description for mode details
683  *
684  * Return:
685  * 0 on success, -errno on failure.
686  */
687 int __init_memblock memblock_add(phys_addr_t base, phys_addr_t size)
688 {
689 	phys_addr_t end = base + size - 1;
690 
691 	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
692 		     &base, &end, (void *)_RET_IP_);
693 
694 	return memblock_add_range(&memblock.memory, base, size, MAX_NUMNODES, 0);
695 }
696 
697 /**
698  * memblock_isolate_range - isolate given range into disjoint memblocks
699  * @type: memblock type to isolate range for
700  * @base: base of range to isolate
701  * @size: size of range to isolate
702  * @start_rgn: out parameter for the start of isolated region
703  * @end_rgn: out parameter for the end of isolated region
704  *
705  * Walk @type and ensure that regions don't cross the boundaries defined by
706  * [@base, @base + @size).  Crossing regions are split at the boundaries,
707  * which may create at most two more regions.  The index of the first
708  * region inside the range is returned in *@start_rgn and end in *@end_rgn.
709  *
710  * Return:
711  * 0 on success, -errno on failure.
712  */
713 static int __init_memblock memblock_isolate_range(struct memblock_type *type,
714 					phys_addr_t base, phys_addr_t size,
715 					int *start_rgn, int *end_rgn)
716 {
717 	phys_addr_t end = base + memblock_cap_size(base, &size);
718 	int idx;
719 	struct memblock_region *rgn;
720 
721 	*start_rgn = *end_rgn = 0;
722 
723 	if (!size)
724 		return 0;
725 
726 	/* we'll create at most two more regions */
727 	while (type->cnt + 2 > type->max)
728 		if (memblock_double_array(type, base, size) < 0)
729 			return -ENOMEM;
730 
731 	for_each_memblock_type(idx, type, rgn) {
732 		phys_addr_t rbase = rgn->base;
733 		phys_addr_t rend = rbase + rgn->size;
734 
735 		if (rbase >= end)
736 			break;
737 		if (rend <= base)
738 			continue;
739 
740 		if (rbase < base) {
741 			/*
742 			 * @rgn intersects from below.  Split and continue
743 			 * to process the next region - the new top half.
744 			 */
745 			rgn->base = base;
746 			rgn->size -= base - rbase;
747 			type->total_size -= base - rbase;
748 			memblock_insert_region(type, idx, rbase, base - rbase,
749 					       memblock_get_region_node(rgn),
750 					       rgn->flags);
751 		} else if (rend > end) {
752 			/*
753 			 * @rgn intersects from above.  Split and redo the
754 			 * current region - the new bottom half.
755 			 */
756 			rgn->base = end;
757 			rgn->size -= end - rbase;
758 			type->total_size -= end - rbase;
759 			memblock_insert_region(type, idx--, rbase, end - rbase,
760 					       memblock_get_region_node(rgn),
761 					       rgn->flags);
762 		} else {
763 			/* @rgn is fully contained, record it */
764 			if (!*end_rgn)
765 				*start_rgn = idx;
766 			*end_rgn = idx + 1;
767 		}
768 	}
769 
770 	return 0;
771 }
772 
773 static int __init_memblock memblock_remove_range(struct memblock_type *type,
774 					  phys_addr_t base, phys_addr_t size)
775 {
776 	int start_rgn, end_rgn;
777 	int i, ret;
778 
779 	ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
780 	if (ret)
781 		return ret;
782 
783 	for (i = end_rgn - 1; i >= start_rgn; i--)
784 		memblock_remove_region(type, i);
785 	return 0;
786 }
787 
788 int __init_memblock memblock_remove(phys_addr_t base, phys_addr_t size)
789 {
790 	phys_addr_t end = base + size - 1;
791 
792 	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
793 		     &base, &end, (void *)_RET_IP_);
794 
795 	return memblock_remove_range(&memblock.memory, base, size);
796 }
797 
798 /**
799  * memblock_free - free boot memory block
800  * @base: phys starting address of the  boot memory block
801  * @size: size of the boot memory block in bytes
802  *
803  * Free boot memory block previously allocated by memblock_alloc_xx() API.
804  * The freeing memory will not be released to the buddy allocator.
805  */
806 int __init_memblock memblock_free(phys_addr_t base, phys_addr_t size)
807 {
808 	phys_addr_t end = base + size - 1;
809 
810 	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
811 		     &base, &end, (void *)_RET_IP_);
812 
813 	kmemleak_free_part_phys(base, size);
814 	return memblock_remove_range(&memblock.reserved, base, size);
815 }
816 
817 int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
818 {
819 	phys_addr_t end = base + size - 1;
820 
821 	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
822 		     &base, &end, (void *)_RET_IP_);
823 
824 	return memblock_add_range(&memblock.reserved, base, size, MAX_NUMNODES, 0);
825 }
826 
827 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
828 int __init_memblock memblock_physmem_add(phys_addr_t base, phys_addr_t size)
829 {
830 	phys_addr_t end = base + size - 1;
831 
832 	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
833 		     &base, &end, (void *)_RET_IP_);
834 
835 	return memblock_add_range(&physmem, base, size, MAX_NUMNODES, 0);
836 }
837 #endif
838 
839 /**
840  * memblock_setclr_flag - set or clear flag for a memory region
841  * @base: base address of the region
842  * @size: size of the region
843  * @set: set or clear the flag
844  * @flag: the flag to update
845  *
846  * This function isolates region [@base, @base + @size), and sets/clears flag
847  *
848  * Return: 0 on success, -errno on failure.
849  */
850 static int __init_memblock memblock_setclr_flag(phys_addr_t base,
851 				phys_addr_t size, int set, int flag)
852 {
853 	struct memblock_type *type = &memblock.memory;
854 	int i, ret, start_rgn, end_rgn;
855 
856 	ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
857 	if (ret)
858 		return ret;
859 
860 	for (i = start_rgn; i < end_rgn; i++) {
861 		struct memblock_region *r = &type->regions[i];
862 
863 		if (set)
864 			r->flags |= flag;
865 		else
866 			r->flags &= ~flag;
867 	}
868 
869 	memblock_merge_regions(type);
870 	return 0;
871 }
872 
873 /**
874  * memblock_mark_hotplug - Mark hotpluggable memory with flag MEMBLOCK_HOTPLUG.
875  * @base: the base phys addr of the region
876  * @size: the size of the region
877  *
878  * Return: 0 on success, -errno on failure.
879  */
880 int __init_memblock memblock_mark_hotplug(phys_addr_t base, phys_addr_t size)
881 {
882 	return memblock_setclr_flag(base, size, 1, MEMBLOCK_HOTPLUG);
883 }
884 
885 /**
886  * memblock_clear_hotplug - Clear flag MEMBLOCK_HOTPLUG for a specified region.
887  * @base: the base phys addr of the region
888  * @size: the size of the region
889  *
890  * Return: 0 on success, -errno on failure.
891  */
892 int __init_memblock memblock_clear_hotplug(phys_addr_t base, phys_addr_t size)
893 {
894 	return memblock_setclr_flag(base, size, 0, MEMBLOCK_HOTPLUG);
895 }
896 
897 /**
898  * memblock_mark_mirror - Mark mirrored memory with flag MEMBLOCK_MIRROR.
899  * @base: the base phys addr of the region
900  * @size: the size of the region
901  *
902  * Return: 0 on success, -errno on failure.
903  */
904 int __init_memblock memblock_mark_mirror(phys_addr_t base, phys_addr_t size)
905 {
906 	system_has_some_mirror = true;
907 
908 	return memblock_setclr_flag(base, size, 1, MEMBLOCK_MIRROR);
909 }
910 
911 /**
912  * memblock_mark_nomap - Mark a memory region with flag MEMBLOCK_NOMAP.
913  * @base: the base phys addr of the region
914  * @size: the size of the region
915  *
916  * The memory regions marked with %MEMBLOCK_NOMAP will not be added to the
917  * direct mapping of the physical memory. These regions will still be
918  * covered by the memory map. The struct page representing NOMAP memory
919  * frames in the memory map will be PageReserved()
920  *
921  * Return: 0 on success, -errno on failure.
922  */
923 int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size)
924 {
925 	return memblock_setclr_flag(base, size, 1, MEMBLOCK_NOMAP);
926 }
927 
928 /**
929  * memblock_clear_nomap - Clear flag MEMBLOCK_NOMAP for a specified region.
930  * @base: the base phys addr of the region
931  * @size: the size of the region
932  *
933  * Return: 0 on success, -errno on failure.
934  */
935 int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size)
936 {
937 	return memblock_setclr_flag(base, size, 0, MEMBLOCK_NOMAP);
938 }
939 
940 static bool should_skip_region(struct memblock_type *type,
941 			       struct memblock_region *m,
942 			       int nid, int flags)
943 {
944 	int m_nid = memblock_get_region_node(m);
945 
946 	/* we never skip regions when iterating memblock.reserved or physmem */
947 	if (type != memblock_memory)
948 		return false;
949 
950 	/* only memory regions are associated with nodes, check it */
951 	if (nid != NUMA_NO_NODE && nid != m_nid)
952 		return true;
953 
954 	/* skip hotpluggable memory regions if needed */
955 	if (movable_node_is_enabled() && memblock_is_hotpluggable(m) &&
956 	    !(flags & MEMBLOCK_HOTPLUG))
957 		return true;
958 
959 	/* if we want mirror memory skip non-mirror memory regions */
960 	if ((flags & MEMBLOCK_MIRROR) && !memblock_is_mirror(m))
961 		return true;
962 
963 	/* skip nomap memory unless we were asked for it explicitly */
964 	if (!(flags & MEMBLOCK_NOMAP) && memblock_is_nomap(m))
965 		return true;
966 
967 	return false;
968 }
969 
970 /**
971  * __next_mem_range - next function for for_each_free_mem_range() etc.
972  * @idx: pointer to u64 loop variable
973  * @nid: node selector, %NUMA_NO_NODE for all nodes
974  * @flags: pick from blocks based on memory attributes
975  * @type_a: pointer to memblock_type from where the range is taken
976  * @type_b: pointer to memblock_type which excludes memory from being taken
977  * @out_start: ptr to phys_addr_t for start address of the range, can be %NULL
978  * @out_end: ptr to phys_addr_t for end address of the range, can be %NULL
979  * @out_nid: ptr to int for nid of the range, can be %NULL
980  *
981  * Find the first area from *@idx which matches @nid, fill the out
982  * parameters, and update *@idx for the next iteration.  The lower 32bit of
983  * *@idx contains index into type_a and the upper 32bit indexes the
984  * areas before each region in type_b.	For example, if type_b regions
985  * look like the following,
986  *
987  *	0:[0-16), 1:[32-48), 2:[128-130)
988  *
989  * The upper 32bit indexes the following regions.
990  *
991  *	0:[0-0), 1:[16-32), 2:[48-128), 3:[130-MAX)
992  *
993  * As both region arrays are sorted, the function advances the two indices
994  * in lockstep and returns each intersection.
995  */
996 void __next_mem_range(u64 *idx, int nid, enum memblock_flags flags,
997 		      struct memblock_type *type_a,
998 		      struct memblock_type *type_b, phys_addr_t *out_start,
999 		      phys_addr_t *out_end, int *out_nid)
1000 {
1001 	int idx_a = *idx & 0xffffffff;
1002 	int idx_b = *idx >> 32;
1003 
1004 	if (WARN_ONCE(nid == MAX_NUMNODES,
1005 	"Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
1006 		nid = NUMA_NO_NODE;
1007 
1008 	for (; idx_a < type_a->cnt; idx_a++) {
1009 		struct memblock_region *m = &type_a->regions[idx_a];
1010 
1011 		phys_addr_t m_start = m->base;
1012 		phys_addr_t m_end = m->base + m->size;
1013 		int	    m_nid = memblock_get_region_node(m);
1014 
1015 		if (should_skip_region(type_a, m, nid, flags))
1016 			continue;
1017 
1018 		if (!type_b) {
1019 			if (out_start)
1020 				*out_start = m_start;
1021 			if (out_end)
1022 				*out_end = m_end;
1023 			if (out_nid)
1024 				*out_nid = m_nid;
1025 			idx_a++;
1026 			*idx = (u32)idx_a | (u64)idx_b << 32;
1027 			return;
1028 		}
1029 
1030 		/* scan areas before each reservation */
1031 		for (; idx_b < type_b->cnt + 1; idx_b++) {
1032 			struct memblock_region *r;
1033 			phys_addr_t r_start;
1034 			phys_addr_t r_end;
1035 
1036 			r = &type_b->regions[idx_b];
1037 			r_start = idx_b ? r[-1].base + r[-1].size : 0;
1038 			r_end = idx_b < type_b->cnt ?
1039 				r->base : PHYS_ADDR_MAX;
1040 
1041 			/*
1042 			 * if idx_b advanced past idx_a,
1043 			 * break out to advance idx_a
1044 			 */
1045 			if (r_start >= m_end)
1046 				break;
1047 			/* if the two regions intersect, we're done */
1048 			if (m_start < r_end) {
1049 				if (out_start)
1050 					*out_start =
1051 						max(m_start, r_start);
1052 				if (out_end)
1053 					*out_end = min(m_end, r_end);
1054 				if (out_nid)
1055 					*out_nid = m_nid;
1056 				/*
1057 				 * The region which ends first is
1058 				 * advanced for the next iteration.
1059 				 */
1060 				if (m_end <= r_end)
1061 					idx_a++;
1062 				else
1063 					idx_b++;
1064 				*idx = (u32)idx_a | (u64)idx_b << 32;
1065 				return;
1066 			}
1067 		}
1068 	}
1069 
1070 	/* signal end of iteration */
1071 	*idx = ULLONG_MAX;
1072 }
1073 
1074 /**
1075  * __next_mem_range_rev - generic next function for for_each_*_range_rev()
1076  *
1077  * @idx: pointer to u64 loop variable
1078  * @nid: node selector, %NUMA_NO_NODE for all nodes
1079  * @flags: pick from blocks based on memory attributes
1080  * @type_a: pointer to memblock_type from where the range is taken
1081  * @type_b: pointer to memblock_type which excludes memory from being taken
1082  * @out_start: ptr to phys_addr_t for start address of the range, can be %NULL
1083  * @out_end: ptr to phys_addr_t for end address of the range, can be %NULL
1084  * @out_nid: ptr to int for nid of the range, can be %NULL
1085  *
1086  * Finds the next range from type_a which is not marked as unsuitable
1087  * in type_b.
1088  *
1089  * Reverse of __next_mem_range().
1090  */
1091 void __init_memblock __next_mem_range_rev(u64 *idx, int nid,
1092 					  enum memblock_flags flags,
1093 					  struct memblock_type *type_a,
1094 					  struct memblock_type *type_b,
1095 					  phys_addr_t *out_start,
1096 					  phys_addr_t *out_end, int *out_nid)
1097 {
1098 	int idx_a = *idx & 0xffffffff;
1099 	int idx_b = *idx >> 32;
1100 
1101 	if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
1102 		nid = NUMA_NO_NODE;
1103 
1104 	if (*idx == (u64)ULLONG_MAX) {
1105 		idx_a = type_a->cnt - 1;
1106 		if (type_b != NULL)
1107 			idx_b = type_b->cnt;
1108 		else
1109 			idx_b = 0;
1110 	}
1111 
1112 	for (; idx_a >= 0; idx_a--) {
1113 		struct memblock_region *m = &type_a->regions[idx_a];
1114 
1115 		phys_addr_t m_start = m->base;
1116 		phys_addr_t m_end = m->base + m->size;
1117 		int m_nid = memblock_get_region_node(m);
1118 
1119 		if (should_skip_region(type_a, m, nid, flags))
1120 			continue;
1121 
1122 		if (!type_b) {
1123 			if (out_start)
1124 				*out_start = m_start;
1125 			if (out_end)
1126 				*out_end = m_end;
1127 			if (out_nid)
1128 				*out_nid = m_nid;
1129 			idx_a--;
1130 			*idx = (u32)idx_a | (u64)idx_b << 32;
1131 			return;
1132 		}
1133 
1134 		/* scan areas before each reservation */
1135 		for (; idx_b >= 0; idx_b--) {
1136 			struct memblock_region *r;
1137 			phys_addr_t r_start;
1138 			phys_addr_t r_end;
1139 
1140 			r = &type_b->regions[idx_b];
1141 			r_start = idx_b ? r[-1].base + r[-1].size : 0;
1142 			r_end = idx_b < type_b->cnt ?
1143 				r->base : PHYS_ADDR_MAX;
1144 			/*
1145 			 * if idx_b advanced past idx_a,
1146 			 * break out to advance idx_a
1147 			 */
1148 
1149 			if (r_end <= m_start)
1150 				break;
1151 			/* if the two regions intersect, we're done */
1152 			if (m_end > r_start) {
1153 				if (out_start)
1154 					*out_start = max(m_start, r_start);
1155 				if (out_end)
1156 					*out_end = min(m_end, r_end);
1157 				if (out_nid)
1158 					*out_nid = m_nid;
1159 				if (m_start >= r_start)
1160 					idx_a--;
1161 				else
1162 					idx_b--;
1163 				*idx = (u32)idx_a | (u64)idx_b << 32;
1164 				return;
1165 			}
1166 		}
1167 	}
1168 	/* signal end of iteration */
1169 	*idx = ULLONG_MAX;
1170 }
1171 
1172 /*
1173  * Common iterator interface used to define for_each_mem_pfn_range().
1174  */
1175 void __init_memblock __next_mem_pfn_range(int *idx, int nid,
1176 				unsigned long *out_start_pfn,
1177 				unsigned long *out_end_pfn, int *out_nid)
1178 {
1179 	struct memblock_type *type = &memblock.memory;
1180 	struct memblock_region *r;
1181 	int r_nid;
1182 
1183 	while (++*idx < type->cnt) {
1184 		r = &type->regions[*idx];
1185 		r_nid = memblock_get_region_node(r);
1186 
1187 		if (PFN_UP(r->base) >= PFN_DOWN(r->base + r->size))
1188 			continue;
1189 		if (nid == MAX_NUMNODES || nid == r_nid)
1190 			break;
1191 	}
1192 	if (*idx >= type->cnt) {
1193 		*idx = -1;
1194 		return;
1195 	}
1196 
1197 	if (out_start_pfn)
1198 		*out_start_pfn = PFN_UP(r->base);
1199 	if (out_end_pfn)
1200 		*out_end_pfn = PFN_DOWN(r->base + r->size);
1201 	if (out_nid)
1202 		*out_nid = r_nid;
1203 }
1204 
1205 /**
1206  * memblock_set_node - set node ID on memblock regions
1207  * @base: base of area to set node ID for
1208  * @size: size of area to set node ID for
1209  * @type: memblock type to set node ID for
1210  * @nid: node ID to set
1211  *
1212  * Set the nid of memblock @type regions in [@base, @base + @size) to @nid.
1213  * Regions which cross the area boundaries are split as necessary.
1214  *
1215  * Return:
1216  * 0 on success, -errno on failure.
1217  */
1218 int __init_memblock memblock_set_node(phys_addr_t base, phys_addr_t size,
1219 				      struct memblock_type *type, int nid)
1220 {
1221 #ifdef CONFIG_NUMA
1222 	int start_rgn, end_rgn;
1223 	int i, ret;
1224 
1225 	ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
1226 	if (ret)
1227 		return ret;
1228 
1229 	for (i = start_rgn; i < end_rgn; i++)
1230 		memblock_set_region_node(&type->regions[i], nid);
1231 
1232 	memblock_merge_regions(type);
1233 #endif
1234 	return 0;
1235 }
1236 
1237 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1238 /**
1239  * __next_mem_pfn_range_in_zone - iterator for for_each_*_range_in_zone()
1240  *
1241  * @idx: pointer to u64 loop variable
1242  * @zone: zone in which all of the memory blocks reside
1243  * @out_spfn: ptr to ulong for start pfn of the range, can be %NULL
1244  * @out_epfn: ptr to ulong for end pfn of the range, can be %NULL
1245  *
1246  * This function is meant to be a zone/pfn specific wrapper for the
1247  * for_each_mem_range type iterators. Specifically they are used in the
1248  * deferred memory init routines and as such we were duplicating much of
1249  * this logic throughout the code. So instead of having it in multiple
1250  * locations it seemed like it would make more sense to centralize this to
1251  * one new iterator that does everything they need.
1252  */
1253 void __init_memblock
1254 __next_mem_pfn_range_in_zone(u64 *idx, struct zone *zone,
1255 			     unsigned long *out_spfn, unsigned long *out_epfn)
1256 {
1257 	int zone_nid = zone_to_nid(zone);
1258 	phys_addr_t spa, epa;
1259 	int nid;
1260 
1261 	__next_mem_range(idx, zone_nid, MEMBLOCK_NONE,
1262 			 &memblock.memory, &memblock.reserved,
1263 			 &spa, &epa, &nid);
1264 
1265 	while (*idx != U64_MAX) {
1266 		unsigned long epfn = PFN_DOWN(epa);
1267 		unsigned long spfn = PFN_UP(spa);
1268 
1269 		/*
1270 		 * Verify the end is at least past the start of the zone and
1271 		 * that we have at least one PFN to initialize.
1272 		 */
1273 		if (zone->zone_start_pfn < epfn && spfn < epfn) {
1274 			/* if we went too far just stop searching */
1275 			if (zone_end_pfn(zone) <= spfn) {
1276 				*idx = U64_MAX;
1277 				break;
1278 			}
1279 
1280 			if (out_spfn)
1281 				*out_spfn = max(zone->zone_start_pfn, spfn);
1282 			if (out_epfn)
1283 				*out_epfn = min(zone_end_pfn(zone), epfn);
1284 
1285 			return;
1286 		}
1287 
1288 		__next_mem_range(idx, zone_nid, MEMBLOCK_NONE,
1289 				 &memblock.memory, &memblock.reserved,
1290 				 &spa, &epa, &nid);
1291 	}
1292 
1293 	/* signal end of iteration */
1294 	if (out_spfn)
1295 		*out_spfn = ULONG_MAX;
1296 	if (out_epfn)
1297 		*out_epfn = 0;
1298 }
1299 
1300 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1301 
1302 /**
1303  * memblock_alloc_range_nid - allocate boot memory block
1304  * @size: size of memory block to be allocated in bytes
1305  * @align: alignment of the region and block's size
1306  * @start: the lower bound of the memory region to allocate (phys address)
1307  * @end: the upper bound of the memory region to allocate (phys address)
1308  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1309  * @exact_nid: control the allocation fall back to other nodes
1310  *
1311  * The allocation is performed from memory region limited by
1312  * memblock.current_limit if @end == %MEMBLOCK_ALLOC_ACCESSIBLE.
1313  *
1314  * If the specified node can not hold the requested memory and @exact_nid
1315  * is false, the allocation falls back to any node in the system.
1316  *
1317  * For systems with memory mirroring, the allocation is attempted first
1318  * from the regions with mirroring enabled and then retried from any
1319  * memory region.
1320  *
1321  * In addition, function sets the min_count to 0 using kmemleak_alloc_phys for
1322  * allocated boot memory block, so that it is never reported as leaks.
1323  *
1324  * Return:
1325  * Physical address of allocated memory block on success, %0 on failure.
1326  */
1327 phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
1328 					phys_addr_t align, phys_addr_t start,
1329 					phys_addr_t end, int nid,
1330 					bool exact_nid)
1331 {
1332 	enum memblock_flags flags = choose_memblock_flags();
1333 	phys_addr_t found;
1334 
1335 	if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
1336 		nid = NUMA_NO_NODE;
1337 
1338 	if (!align) {
1339 		/* Can't use WARNs this early in boot on powerpc */
1340 		dump_stack();
1341 		align = SMP_CACHE_BYTES;
1342 	}
1343 
1344 again:
1345 	found = memblock_find_in_range_node(size, align, start, end, nid,
1346 					    flags);
1347 	if (found && !memblock_reserve(found, size))
1348 		goto done;
1349 
1350 	if (nid != NUMA_NO_NODE && !exact_nid) {
1351 		found = memblock_find_in_range_node(size, align, start,
1352 						    end, NUMA_NO_NODE,
1353 						    flags);
1354 		if (found && !memblock_reserve(found, size))
1355 			goto done;
1356 	}
1357 
1358 	if (flags & MEMBLOCK_MIRROR) {
1359 		flags &= ~MEMBLOCK_MIRROR;
1360 		pr_warn("Could not allocate %pap bytes of mirrored memory\n",
1361 			&size);
1362 		goto again;
1363 	}
1364 
1365 	return 0;
1366 
1367 done:
1368 	/* Skip kmemleak for kasan_init() due to high volume. */
1369 	if (end != MEMBLOCK_ALLOC_KASAN)
1370 		/*
1371 		 * The min_count is set to 0 so that memblock allocated
1372 		 * blocks are never reported as leaks. This is because many
1373 		 * of these blocks are only referred via the physical
1374 		 * address which is not looked up by kmemleak.
1375 		 */
1376 		kmemleak_alloc_phys(found, size, 0, 0);
1377 
1378 	return found;
1379 }
1380 
1381 /**
1382  * memblock_phys_alloc_range - allocate a memory block inside specified range
1383  * @size: size of memory block to be allocated in bytes
1384  * @align: alignment of the region and block's size
1385  * @start: the lower bound of the memory region to allocate (physical address)
1386  * @end: the upper bound of the memory region to allocate (physical address)
1387  *
1388  * Allocate @size bytes in the between @start and @end.
1389  *
1390  * Return: physical address of the allocated memory block on success,
1391  * %0 on failure.
1392  */
1393 phys_addr_t __init memblock_phys_alloc_range(phys_addr_t size,
1394 					     phys_addr_t align,
1395 					     phys_addr_t start,
1396 					     phys_addr_t end)
1397 {
1398 	memblock_dbg("%s: %llu bytes align=0x%llx from=%pa max_addr=%pa %pS\n",
1399 		     __func__, (u64)size, (u64)align, &start, &end,
1400 		     (void *)_RET_IP_);
1401 	return memblock_alloc_range_nid(size, align, start, end, NUMA_NO_NODE,
1402 					false);
1403 }
1404 
1405 /**
1406  * memblock_phys_alloc_try_nid - allocate a memory block from specified NUMA node
1407  * @size: size of memory block to be allocated in bytes
1408  * @align: alignment of the region and block's size
1409  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1410  *
1411  * Allocates memory block from the specified NUMA node. If the node
1412  * has no available memory, attempts to allocated from any node in the
1413  * system.
1414  *
1415  * Return: physical address of the allocated memory block on success,
1416  * %0 on failure.
1417  */
1418 phys_addr_t __init memblock_phys_alloc_try_nid(phys_addr_t size, phys_addr_t align, int nid)
1419 {
1420 	return memblock_alloc_range_nid(size, align, 0,
1421 					MEMBLOCK_ALLOC_ACCESSIBLE, nid, false);
1422 }
1423 
1424 /**
1425  * memblock_alloc_internal - allocate boot memory block
1426  * @size: size of memory block to be allocated in bytes
1427  * @align: alignment of the region and block's size
1428  * @min_addr: the lower bound of the memory region to allocate (phys address)
1429  * @max_addr: the upper bound of the memory region to allocate (phys address)
1430  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1431  * @exact_nid: control the allocation fall back to other nodes
1432  *
1433  * Allocates memory block using memblock_alloc_range_nid() and
1434  * converts the returned physical address to virtual.
1435  *
1436  * The @min_addr limit is dropped if it can not be satisfied and the allocation
1437  * will fall back to memory below @min_addr. Other constraints, such
1438  * as node and mirrored memory will be handled again in
1439  * memblock_alloc_range_nid().
1440  *
1441  * Return:
1442  * Virtual address of allocated memory block on success, NULL on failure.
1443  */
1444 static void * __init memblock_alloc_internal(
1445 				phys_addr_t size, phys_addr_t align,
1446 				phys_addr_t min_addr, phys_addr_t max_addr,
1447 				int nid, bool exact_nid)
1448 {
1449 	phys_addr_t alloc;
1450 
1451 	/*
1452 	 * Detect any accidental use of these APIs after slab is ready, as at
1453 	 * this moment memblock may be deinitialized already and its
1454 	 * internal data may be destroyed (after execution of memblock_free_all)
1455 	 */
1456 	if (WARN_ON_ONCE(slab_is_available()))
1457 		return kzalloc_node(size, GFP_NOWAIT, nid);
1458 
1459 	if (max_addr > memblock.current_limit)
1460 		max_addr = memblock.current_limit;
1461 
1462 	alloc = memblock_alloc_range_nid(size, align, min_addr, max_addr, nid,
1463 					exact_nid);
1464 
1465 	/* retry allocation without lower limit */
1466 	if (!alloc && min_addr)
1467 		alloc = memblock_alloc_range_nid(size, align, 0, max_addr, nid,
1468 						exact_nid);
1469 
1470 	if (!alloc)
1471 		return NULL;
1472 
1473 	return phys_to_virt(alloc);
1474 }
1475 
1476 /**
1477  * memblock_alloc_exact_nid_raw - allocate boot memory block on the exact node
1478  * without zeroing memory
1479  * @size: size of memory block to be allocated in bytes
1480  * @align: alignment of the region and block's size
1481  * @min_addr: the lower bound of the memory region from where the allocation
1482  *	  is preferred (phys address)
1483  * @max_addr: the upper bound of the memory region from where the allocation
1484  *	      is preferred (phys address), or %MEMBLOCK_ALLOC_ACCESSIBLE to
1485  *	      allocate only from memory limited by memblock.current_limit value
1486  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1487  *
1488  * Public function, provides additional debug information (including caller
1489  * info), if enabled. Does not zero allocated memory.
1490  *
1491  * Return:
1492  * Virtual address of allocated memory block on success, NULL on failure.
1493  */
1494 void * __init memblock_alloc_exact_nid_raw(
1495 			phys_addr_t size, phys_addr_t align,
1496 			phys_addr_t min_addr, phys_addr_t max_addr,
1497 			int nid)
1498 {
1499 	memblock_dbg("%s: %llu bytes align=0x%llx nid=%d from=%pa max_addr=%pa %pS\n",
1500 		     __func__, (u64)size, (u64)align, nid, &min_addr,
1501 		     &max_addr, (void *)_RET_IP_);
1502 
1503 	return memblock_alloc_internal(size, align, min_addr, max_addr, nid,
1504 				       true);
1505 }
1506 
1507 /**
1508  * memblock_alloc_try_nid_raw - allocate boot memory block without zeroing
1509  * memory and without panicking
1510  * @size: size of memory block to be allocated in bytes
1511  * @align: alignment of the region and block's size
1512  * @min_addr: the lower bound of the memory region from where the allocation
1513  *	  is preferred (phys address)
1514  * @max_addr: the upper bound of the memory region from where the allocation
1515  *	      is preferred (phys address), or %MEMBLOCK_ALLOC_ACCESSIBLE to
1516  *	      allocate only from memory limited by memblock.current_limit value
1517  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1518  *
1519  * Public function, provides additional debug information (including caller
1520  * info), if enabled. Does not zero allocated memory, does not panic if request
1521  * cannot be satisfied.
1522  *
1523  * Return:
1524  * Virtual address of allocated memory block on success, NULL on failure.
1525  */
1526 void * __init memblock_alloc_try_nid_raw(
1527 			phys_addr_t size, phys_addr_t align,
1528 			phys_addr_t min_addr, phys_addr_t max_addr,
1529 			int nid)
1530 {
1531 	memblock_dbg("%s: %llu bytes align=0x%llx nid=%d from=%pa max_addr=%pa %pS\n",
1532 		     __func__, (u64)size, (u64)align, nid, &min_addr,
1533 		     &max_addr, (void *)_RET_IP_);
1534 
1535 	return memblock_alloc_internal(size, align, min_addr, max_addr, nid,
1536 				       false);
1537 }
1538 
1539 /**
1540  * memblock_alloc_try_nid - allocate boot memory block
1541  * @size: size of memory block to be allocated in bytes
1542  * @align: alignment of the region and block's size
1543  * @min_addr: the lower bound of the memory region from where the allocation
1544  *	  is preferred (phys address)
1545  * @max_addr: the upper bound of the memory region from where the allocation
1546  *	      is preferred (phys address), or %MEMBLOCK_ALLOC_ACCESSIBLE to
1547  *	      allocate only from memory limited by memblock.current_limit value
1548  * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
1549  *
1550  * Public function, provides additional debug information (including caller
1551  * info), if enabled. This function zeroes the allocated memory.
1552  *
1553  * Return:
1554  * Virtual address of allocated memory block on success, NULL on failure.
1555  */
1556 void * __init memblock_alloc_try_nid(
1557 			phys_addr_t size, phys_addr_t align,
1558 			phys_addr_t min_addr, phys_addr_t max_addr,
1559 			int nid)
1560 {
1561 	void *ptr;
1562 
1563 	memblock_dbg("%s: %llu bytes align=0x%llx nid=%d from=%pa max_addr=%pa %pS\n",
1564 		     __func__, (u64)size, (u64)align, nid, &min_addr,
1565 		     &max_addr, (void *)_RET_IP_);
1566 	ptr = memblock_alloc_internal(size, align,
1567 					   min_addr, max_addr, nid, false);
1568 	if (ptr)
1569 		memset(ptr, 0, size);
1570 
1571 	return ptr;
1572 }
1573 
1574 /**
1575  * __memblock_free_late - free pages directly to buddy allocator
1576  * @base: phys starting address of the  boot memory block
1577  * @size: size of the boot memory block in bytes
1578  *
1579  * This is only useful when the memblock allocator has already been torn
1580  * down, but we are still initializing the system.  Pages are released directly
1581  * to the buddy allocator.
1582  */
1583 void __init __memblock_free_late(phys_addr_t base, phys_addr_t size)
1584 {
1585 	phys_addr_t cursor, end;
1586 
1587 	end = base + size - 1;
1588 	memblock_dbg("%s: [%pa-%pa] %pS\n",
1589 		     __func__, &base, &end, (void *)_RET_IP_);
1590 	kmemleak_free_part_phys(base, size);
1591 	cursor = PFN_UP(base);
1592 	end = PFN_DOWN(base + size);
1593 
1594 	for (; cursor < end; cursor++) {
1595 		memblock_free_pages(pfn_to_page(cursor), cursor, 0);
1596 		totalram_pages_inc();
1597 	}
1598 }
1599 
1600 /*
1601  * Remaining API functions
1602  */
1603 
1604 phys_addr_t __init_memblock memblock_phys_mem_size(void)
1605 {
1606 	return memblock.memory.total_size;
1607 }
1608 
1609 phys_addr_t __init_memblock memblock_reserved_size(void)
1610 {
1611 	return memblock.reserved.total_size;
1612 }
1613 
1614 /* lowest address */
1615 phys_addr_t __init_memblock memblock_start_of_DRAM(void)
1616 {
1617 	return memblock.memory.regions[0].base;
1618 }
1619 
1620 phys_addr_t __init_memblock memblock_end_of_DRAM(void)
1621 {
1622 	int idx = memblock.memory.cnt - 1;
1623 
1624 	return (memblock.memory.regions[idx].base + memblock.memory.regions[idx].size);
1625 }
1626 
1627 static phys_addr_t __init_memblock __find_max_addr(phys_addr_t limit)
1628 {
1629 	phys_addr_t max_addr = PHYS_ADDR_MAX;
1630 	struct memblock_region *r;
1631 
1632 	/*
1633 	 * translate the memory @limit size into the max address within one of
1634 	 * the memory memblock regions, if the @limit exceeds the total size
1635 	 * of those regions, max_addr will keep original value PHYS_ADDR_MAX
1636 	 */
1637 	for_each_mem_region(r) {
1638 		if (limit <= r->size) {
1639 			max_addr = r->base + limit;
1640 			break;
1641 		}
1642 		limit -= r->size;
1643 	}
1644 
1645 	return max_addr;
1646 }
1647 
1648 void __init memblock_enforce_memory_limit(phys_addr_t limit)
1649 {
1650 	phys_addr_t max_addr;
1651 
1652 	if (!limit)
1653 		return;
1654 
1655 	max_addr = __find_max_addr(limit);
1656 
1657 	/* @limit exceeds the total size of the memory, do nothing */
1658 	if (max_addr == PHYS_ADDR_MAX)
1659 		return;
1660 
1661 	/* truncate both memory and reserved regions */
1662 	memblock_remove_range(&memblock.memory, max_addr,
1663 			      PHYS_ADDR_MAX);
1664 	memblock_remove_range(&memblock.reserved, max_addr,
1665 			      PHYS_ADDR_MAX);
1666 }
1667 
1668 void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size)
1669 {
1670 	int start_rgn, end_rgn;
1671 	int i, ret;
1672 
1673 	if (!size)
1674 		return;
1675 
1676 	if (memblock.memory.cnt <= 1) {
1677 		pr_warn("%s: No memory registered yet\n", __func__);
1678 		return;
1679 	}
1680 
1681 	ret = memblock_isolate_range(&memblock.memory, base, size,
1682 						&start_rgn, &end_rgn);
1683 	if (ret)
1684 		return;
1685 
1686 	/* remove all the MAP regions */
1687 	for (i = memblock.memory.cnt - 1; i >= end_rgn; i--)
1688 		if (!memblock_is_nomap(&memblock.memory.regions[i]))
1689 			memblock_remove_region(&memblock.memory, i);
1690 
1691 	for (i = start_rgn - 1; i >= 0; i--)
1692 		if (!memblock_is_nomap(&memblock.memory.regions[i]))
1693 			memblock_remove_region(&memblock.memory, i);
1694 
1695 	/* truncate the reserved regions */
1696 	memblock_remove_range(&memblock.reserved, 0, base);
1697 	memblock_remove_range(&memblock.reserved,
1698 			base + size, PHYS_ADDR_MAX);
1699 }
1700 
1701 void __init memblock_mem_limit_remove_map(phys_addr_t limit)
1702 {
1703 	phys_addr_t max_addr;
1704 
1705 	if (!limit)
1706 		return;
1707 
1708 	max_addr = __find_max_addr(limit);
1709 
1710 	/* @limit exceeds the total size of the memory, do nothing */
1711 	if (max_addr == PHYS_ADDR_MAX)
1712 		return;
1713 
1714 	memblock_cap_memory_range(0, max_addr);
1715 }
1716 
1717 static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr)
1718 {
1719 	unsigned int left = 0, right = type->cnt;
1720 
1721 	do {
1722 		unsigned int mid = (right + left) / 2;
1723 
1724 		if (addr < type->regions[mid].base)
1725 			right = mid;
1726 		else if (addr >= (type->regions[mid].base +
1727 				  type->regions[mid].size))
1728 			left = mid + 1;
1729 		else
1730 			return mid;
1731 	} while (left < right);
1732 	return -1;
1733 }
1734 
1735 bool __init_memblock memblock_is_reserved(phys_addr_t addr)
1736 {
1737 	return memblock_search(&memblock.reserved, addr) != -1;
1738 }
1739 
1740 bool __init_memblock memblock_is_memory(phys_addr_t addr)
1741 {
1742 	return memblock_search(&memblock.memory, addr) != -1;
1743 }
1744 
1745 bool __init_memblock memblock_is_map_memory(phys_addr_t addr)
1746 {
1747 	int i = memblock_search(&memblock.memory, addr);
1748 
1749 	if (i == -1)
1750 		return false;
1751 	return !memblock_is_nomap(&memblock.memory.regions[i]);
1752 }
1753 
1754 int __init_memblock memblock_search_pfn_nid(unsigned long pfn,
1755 			 unsigned long *start_pfn, unsigned long *end_pfn)
1756 {
1757 	struct memblock_type *type = &memblock.memory;
1758 	int mid = memblock_search(type, PFN_PHYS(pfn));
1759 
1760 	if (mid == -1)
1761 		return -1;
1762 
1763 	*start_pfn = PFN_DOWN(type->regions[mid].base);
1764 	*end_pfn = PFN_DOWN(type->regions[mid].base + type->regions[mid].size);
1765 
1766 	return memblock_get_region_node(&type->regions[mid]);
1767 }
1768 
1769 /**
1770  * memblock_is_region_memory - check if a region is a subset of memory
1771  * @base: base of region to check
1772  * @size: size of region to check
1773  *
1774  * Check if the region [@base, @base + @size) is a subset of a memory block.
1775  *
1776  * Return:
1777  * 0 if false, non-zero if true
1778  */
1779 bool __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size)
1780 {
1781 	int idx = memblock_search(&memblock.memory, base);
1782 	phys_addr_t end = base + memblock_cap_size(base, &size);
1783 
1784 	if (idx == -1)
1785 		return false;
1786 	return (memblock.memory.regions[idx].base +
1787 		 memblock.memory.regions[idx].size) >= end;
1788 }
1789 
1790 /**
1791  * memblock_is_region_reserved - check if a region intersects reserved memory
1792  * @base: base of region to check
1793  * @size: size of region to check
1794  *
1795  * Check if the region [@base, @base + @size) intersects a reserved
1796  * memory block.
1797  *
1798  * Return:
1799  * True if they intersect, false if not.
1800  */
1801 bool __init_memblock memblock_is_region_reserved(phys_addr_t base, phys_addr_t size)
1802 {
1803 	return memblock_overlaps_region(&memblock.reserved, base, size);
1804 }
1805 
1806 void __init_memblock memblock_trim_memory(phys_addr_t align)
1807 {
1808 	phys_addr_t start, end, orig_start, orig_end;
1809 	struct memblock_region *r;
1810 
1811 	for_each_mem_region(r) {
1812 		orig_start = r->base;
1813 		orig_end = r->base + r->size;
1814 		start = round_up(orig_start, align);
1815 		end = round_down(orig_end, align);
1816 
1817 		if (start == orig_start && end == orig_end)
1818 			continue;
1819 
1820 		if (start < end) {
1821 			r->base = start;
1822 			r->size = end - start;
1823 		} else {
1824 			memblock_remove_region(&memblock.memory,
1825 					       r - memblock.memory.regions);
1826 			r--;
1827 		}
1828 	}
1829 }
1830 
1831 void __init_memblock memblock_set_current_limit(phys_addr_t limit)
1832 {
1833 	memblock.current_limit = limit;
1834 }
1835 
1836 phys_addr_t __init_memblock memblock_get_current_limit(void)
1837 {
1838 	return memblock.current_limit;
1839 }
1840 
1841 static void __init_memblock memblock_dump(struct memblock_type *type)
1842 {
1843 	phys_addr_t base, end, size;
1844 	enum memblock_flags flags;
1845 	int idx;
1846 	struct memblock_region *rgn;
1847 
1848 	pr_info(" %s.cnt  = 0x%lx\n", type->name, type->cnt);
1849 
1850 	for_each_memblock_type(idx, type, rgn) {
1851 		char nid_buf[32] = "";
1852 
1853 		base = rgn->base;
1854 		size = rgn->size;
1855 		end = base + size - 1;
1856 		flags = rgn->flags;
1857 #ifdef CONFIG_NUMA
1858 		if (memblock_get_region_node(rgn) != MAX_NUMNODES)
1859 			snprintf(nid_buf, sizeof(nid_buf), " on node %d",
1860 				 memblock_get_region_node(rgn));
1861 #endif
1862 		pr_info(" %s[%#x]\t[%pa-%pa], %pa bytes%s flags: %#x\n",
1863 			type->name, idx, &base, &end, &size, nid_buf, flags);
1864 	}
1865 }
1866 
1867 static void __init_memblock __memblock_dump_all(void)
1868 {
1869 	pr_info("MEMBLOCK configuration:\n");
1870 	pr_info(" memory size = %pa reserved size = %pa\n",
1871 		&memblock.memory.total_size,
1872 		&memblock.reserved.total_size);
1873 
1874 	memblock_dump(&memblock.memory);
1875 	memblock_dump(&memblock.reserved);
1876 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
1877 	memblock_dump(&physmem);
1878 #endif
1879 }
1880 
1881 void __init_memblock memblock_dump_all(void)
1882 {
1883 	if (memblock_debug)
1884 		__memblock_dump_all();
1885 }
1886 
1887 void __init memblock_allow_resize(void)
1888 {
1889 	memblock_can_resize = 1;
1890 }
1891 
1892 static int __init early_memblock(char *p)
1893 {
1894 	if (p && strstr(p, "debug"))
1895 		memblock_debug = 1;
1896 	return 0;
1897 }
1898 early_param("memblock", early_memblock);
1899 
1900 static void __init free_memmap(unsigned long start_pfn, unsigned long end_pfn)
1901 {
1902 	struct page *start_pg, *end_pg;
1903 	phys_addr_t pg, pgend;
1904 
1905 	/*
1906 	 * Convert start_pfn/end_pfn to a struct page pointer.
1907 	 */
1908 	start_pg = pfn_to_page(start_pfn - 1) + 1;
1909 	end_pg = pfn_to_page(end_pfn - 1) + 1;
1910 
1911 	/*
1912 	 * Convert to physical addresses, and round start upwards and end
1913 	 * downwards.
1914 	 */
1915 	pg = PAGE_ALIGN(__pa(start_pg));
1916 	pgend = __pa(end_pg) & PAGE_MASK;
1917 
1918 	/*
1919 	 * If there are free pages between these, free the section of the
1920 	 * memmap array.
1921 	 */
1922 	if (pg < pgend)
1923 		memblock_free(pg, pgend - pg);
1924 }
1925 
1926 /*
1927  * The mem_map array can get very big.  Free the unused area of the memory map.
1928  */
1929 static void __init free_unused_memmap(void)
1930 {
1931 	unsigned long start, end, prev_end = 0;
1932 	int i;
1933 
1934 	if (!IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) ||
1935 	    IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
1936 		return;
1937 
1938 	/*
1939 	 * This relies on each bank being in address order.
1940 	 * The banks are sorted previously in bootmem_init().
1941 	 */
1942 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, NULL) {
1943 #ifdef CONFIG_SPARSEMEM
1944 		/*
1945 		 * Take care not to free memmap entries that don't exist
1946 		 * due to SPARSEMEM sections which aren't present.
1947 		 */
1948 		start = min(start, ALIGN(prev_end, PAGES_PER_SECTION));
1949 #endif
1950 		/*
1951 		 * Align down here since many operations in VM subsystem
1952 		 * presume that there are no holes in the memory map inside
1953 		 * a pageblock
1954 		 */
1955 		start = round_down(start, pageblock_nr_pages);
1956 
1957 		/*
1958 		 * If we had a previous bank, and there is a space
1959 		 * between the current bank and the previous, free it.
1960 		 */
1961 		if (prev_end && prev_end < start)
1962 			free_memmap(prev_end, start);
1963 
1964 		/*
1965 		 * Align up here since many operations in VM subsystem
1966 		 * presume that there are no holes in the memory map inside
1967 		 * a pageblock
1968 		 */
1969 		prev_end = ALIGN(end, pageblock_nr_pages);
1970 	}
1971 
1972 #ifdef CONFIG_SPARSEMEM
1973 	if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION)) {
1974 		prev_end = ALIGN(end, pageblock_nr_pages);
1975 		free_memmap(prev_end, ALIGN(prev_end, PAGES_PER_SECTION));
1976 	}
1977 #endif
1978 }
1979 
1980 static void __init __free_pages_memory(unsigned long start, unsigned long end)
1981 {
1982 	int order;
1983 
1984 	while (start < end) {
1985 		order = min(MAX_ORDER - 1UL, __ffs(start));
1986 
1987 		while (start + (1UL << order) > end)
1988 			order--;
1989 
1990 		memblock_free_pages(pfn_to_page(start), start, order);
1991 
1992 		start += (1UL << order);
1993 	}
1994 }
1995 
1996 static unsigned long __init __free_memory_core(phys_addr_t start,
1997 				 phys_addr_t end)
1998 {
1999 	unsigned long start_pfn = PFN_UP(start);
2000 	unsigned long end_pfn = min_t(unsigned long,
2001 				      PFN_DOWN(end), max_low_pfn);
2002 
2003 	if (start_pfn >= end_pfn)
2004 		return 0;
2005 
2006 	__free_pages_memory(start_pfn, end_pfn);
2007 
2008 	return end_pfn - start_pfn;
2009 }
2010 
2011 static void __init memmap_init_reserved_pages(void)
2012 {
2013 	struct memblock_region *region;
2014 	phys_addr_t start, end;
2015 	u64 i;
2016 
2017 	/* initialize struct pages for the reserved regions */
2018 	for_each_reserved_mem_range(i, &start, &end)
2019 		reserve_bootmem_region(start, end);
2020 
2021 	/* and also treat struct pages for the NOMAP regions as PageReserved */
2022 	for_each_mem_region(region) {
2023 		if (memblock_is_nomap(region)) {
2024 			start = region->base;
2025 			end = start + region->size;
2026 			reserve_bootmem_region(start, end);
2027 		}
2028 	}
2029 }
2030 
2031 static unsigned long __init free_low_memory_core_early(void)
2032 {
2033 	unsigned long count = 0;
2034 	phys_addr_t start, end;
2035 	u64 i;
2036 
2037 	memblock_clear_hotplug(0, -1);
2038 
2039 	memmap_init_reserved_pages();
2040 
2041 	/*
2042 	 * We need to use NUMA_NO_NODE instead of NODE_DATA(0)->node_id
2043 	 *  because in some case like Node0 doesn't have RAM installed
2044 	 *  low ram will be on Node1
2045 	 */
2046 	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end,
2047 				NULL)
2048 		count += __free_memory_core(start, end);
2049 
2050 	return count;
2051 }
2052 
2053 static int reset_managed_pages_done __initdata;
2054 
2055 void reset_node_managed_pages(pg_data_t *pgdat)
2056 {
2057 	struct zone *z;
2058 
2059 	for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
2060 		atomic_long_set(&z->managed_pages, 0);
2061 }
2062 
2063 void __init reset_all_zones_managed_pages(void)
2064 {
2065 	struct pglist_data *pgdat;
2066 
2067 	if (reset_managed_pages_done)
2068 		return;
2069 
2070 	for_each_online_pgdat(pgdat)
2071 		reset_node_managed_pages(pgdat);
2072 
2073 	reset_managed_pages_done = 1;
2074 }
2075 
2076 /**
2077  * memblock_free_all - release free pages to the buddy allocator
2078  */
2079 void __init memblock_free_all(void)
2080 {
2081 	unsigned long pages;
2082 
2083 	free_unused_memmap();
2084 	reset_all_zones_managed_pages();
2085 
2086 	pages = free_low_memory_core_early();
2087 	totalram_pages_add(pages);
2088 }
2089 
2090 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_ARCH_KEEP_MEMBLOCK)
2091 
2092 static int memblock_debug_show(struct seq_file *m, void *private)
2093 {
2094 	struct memblock_type *type = m->private;
2095 	struct memblock_region *reg;
2096 	int i;
2097 	phys_addr_t end;
2098 
2099 	for (i = 0; i < type->cnt; i++) {
2100 		reg = &type->regions[i];
2101 		end = reg->base + reg->size - 1;
2102 
2103 		seq_printf(m, "%4d: ", i);
2104 		seq_printf(m, "%pa..%pa\n", &reg->base, &end);
2105 	}
2106 	return 0;
2107 }
2108 DEFINE_SHOW_ATTRIBUTE(memblock_debug);
2109 
2110 static int __init memblock_init_debugfs(void)
2111 {
2112 	struct dentry *root = debugfs_create_dir("memblock", NULL);
2113 
2114 	debugfs_create_file("memory", 0444, root,
2115 			    &memblock.memory, &memblock_debug_fops);
2116 	debugfs_create_file("reserved", 0444, root,
2117 			    &memblock.reserved, &memblock_debug_fops);
2118 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
2119 	debugfs_create_file("physmem", 0444, root, &physmem,
2120 			    &memblock_debug_fops);
2121 #endif
2122 
2123 	return 0;
2124 }
2125 __initcall(memblock_init_debugfs);
2126 
2127 #endif /* CONFIG_DEBUG_FS */
2128