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  1/*
  2 *  bootmem - A boot-time physical memory allocator and configurator
  3 *
  4 *  Copyright (C) 1999 Ingo Molnar
  5 *                1999 Kanoj Sarcar, SGI
  6 *                2008 Johannes Weiner
  7 *
  8 * Access to this subsystem has to be serialized externally (which is true
  9 * for the boot process anyway).
 10 */
 11#include <linux/init.h>
 12#include <linux/pfn.h>
 13#include <linux/slab.h>
 14#include <linux/bootmem.h>
 15#include <linux/export.h>
 16#include <linux/kmemleak.h>
 17#include <linux/range.h>
 18#include <linux/memblock.h>
 19
 20#include <asm/bug.h>
 21#include <asm/io.h>
 22#include <asm/processor.h>
 23
 24#include "internal.h"
 25
 26#ifndef CONFIG_NEED_MULTIPLE_NODES
 27struct pglist_data __refdata contig_page_data = {
 28	.bdata = &bootmem_node_data[0]
 29};
 30EXPORT_SYMBOL(contig_page_data);
 31#endif
 32
 33unsigned long max_low_pfn;
 34unsigned long min_low_pfn;
 35unsigned long max_pfn;
 36
 37bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;
 38
 39static struct list_head bdata_list __initdata = LIST_HEAD_INIT(bdata_list);
 40
 41static int bootmem_debug;
 42
 43static int __init bootmem_debug_setup(char *buf)
 44{
 45	bootmem_debug = 1;
 46	return 0;
 47}
 48early_param("bootmem_debug", bootmem_debug_setup);
 49
 50#define bdebug(fmt, args...) ({				\
 51	if (unlikely(bootmem_debug))			\
 52		printk(KERN_INFO			\
 53			"bootmem::%s " fmt,		\
 54			__func__, ## args);		\
 55})
 56
 57static unsigned long __init bootmap_bytes(unsigned long pages)
 58{
 59	unsigned long bytes = DIV_ROUND_UP(pages, 8);
 60
 61	return ALIGN(bytes, sizeof(long));
 62}
 63
 64/**
 65 * bootmem_bootmap_pages - calculate bitmap size in pages
 66 * @pages: number of pages the bitmap has to represent
 67 */
 68unsigned long __init bootmem_bootmap_pages(unsigned long pages)
 69{
 70	unsigned long bytes = bootmap_bytes(pages);
 71
 72	return PAGE_ALIGN(bytes) >> PAGE_SHIFT;
 73}
 74
 75/*
 76 * link bdata in order
 77 */
 78static void __init link_bootmem(bootmem_data_t *bdata)
 79{
 80	bootmem_data_t *ent;
 81
 82	list_for_each_entry(ent, &bdata_list, list) {
 83		if (bdata->node_min_pfn < ent->node_min_pfn) {
 84			list_add_tail(&bdata->list, &ent->list);
 85			return;
 86		}
 87	}
 88
 89	list_add_tail(&bdata->list, &bdata_list);
 90}
 91
 92/*
 93 * Called once to set up the allocator itself.
 94 */
 95static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
 96	unsigned long mapstart, unsigned long start, unsigned long end)
 97{
 98	unsigned long mapsize;
 99
100	mminit_validate_memmodel_limits(&start, &end);
101	bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
102	bdata->node_min_pfn = start;
103	bdata->node_low_pfn = end;
104	link_bootmem(bdata);
105
106	/*
107	 * Initially all pages are reserved - setup_arch() has to
108	 * register free RAM areas explicitly.
109	 */
110	mapsize = bootmap_bytes(end - start);
111	memset(bdata->node_bootmem_map, 0xff, mapsize);
112
113	bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx\n",
114		bdata - bootmem_node_data, start, mapstart, end, mapsize);
115
116	return mapsize;
117}
118
119/**
120 * init_bootmem_node - register a node as boot memory
121 * @pgdat: node to register
122 * @freepfn: pfn where the bitmap for this node is to be placed
123 * @startpfn: first pfn on the node
124 * @endpfn: first pfn after the node
125 *
126 * Returns the number of bytes needed to hold the bitmap for this node.
127 */
128unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
129				unsigned long startpfn, unsigned long endpfn)
130{
131	return init_bootmem_core(pgdat->bdata, freepfn, startpfn, endpfn);
132}
133
134/**
135 * init_bootmem - register boot memory
136 * @start: pfn where the bitmap is to be placed
137 * @pages: number of available physical pages
138 *
139 * Returns the number of bytes needed to hold the bitmap.
140 */
141unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
142{
143	max_low_pfn = pages;
144	min_low_pfn = start;
145	return init_bootmem_core(NODE_DATA(0)->bdata, start, 0, pages);
146}
147
148/*
149 * free_bootmem_late - free bootmem pages directly to page allocator
150 * @addr: starting address of the range
151 * @size: size of the range in bytes
152 *
153 * This is only useful when the bootmem allocator has already been torn
154 * down, but we are still initializing the system.  Pages are given directly
155 * to the page allocator, no bootmem metadata is updated because it is gone.
156 */
157void __init free_bootmem_late(unsigned long addr, unsigned long size)
158{
159	unsigned long cursor, end;
160
161	kmemleak_free_part(__va(addr), size);
162
163	cursor = PFN_UP(addr);
164	end = PFN_DOWN(addr + size);
165
166	for (; cursor < end; cursor++) {
167		__free_pages_bootmem(pfn_to_page(cursor), 0);
168		totalram_pages++;
169	}
170}
171
172static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
173{
174	struct page *page;
175	unsigned long start, end, pages, count = 0;
176
177	if (!bdata->node_bootmem_map)
178		return 0;
179
180	start = bdata->node_min_pfn;
181	end = bdata->node_low_pfn;
182
183	bdebug("nid=%td start=%lx end=%lx\n",
184		bdata - bootmem_node_data, start, end);
185
186	while (start < end) {
187		unsigned long *map, idx, vec;
188
189		map = bdata->node_bootmem_map;
190		idx = start - bdata->node_min_pfn;
191		vec = ~map[idx / BITS_PER_LONG];
192		/*
193		 * If we have a properly aligned and fully unreserved
194		 * BITS_PER_LONG block of pages in front of us, free
195		 * it in one go.
196		 */
197		if (IS_ALIGNED(start, BITS_PER_LONG) && vec == ~0UL) {
198			int order = ilog2(BITS_PER_LONG);
199
200			__free_pages_bootmem(pfn_to_page(start), order);
201			count += BITS_PER_LONG;
202			start += BITS_PER_LONG;
203		} else {
204			unsigned long off = 0;
205
206			vec >>= start & (BITS_PER_LONG - 1);
207			while (vec) {
208				if (vec & 1) {
209					page = pfn_to_page(start + off);
210					__free_pages_bootmem(page, 0);
211					count++;
212				}
213				vec >>= 1;
214				off++;
215			}
216			start = ALIGN(start + 1, BITS_PER_LONG);
217		}
218	}
219
220	page = virt_to_page(bdata->node_bootmem_map);
221	pages = bdata->node_low_pfn - bdata->node_min_pfn;
222	pages = bootmem_bootmap_pages(pages);
223	count += pages;
224	while (pages--)
225		__free_pages_bootmem(page++, 0);
226
227	bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
228
229	return count;
230}
231
232/**
233 * free_all_bootmem_node - release a node's free pages to the buddy allocator
234 * @pgdat: node to be released
235 *
236 * Returns the number of pages actually released.
237 */
238unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
239{
240	register_page_bootmem_info_node(pgdat);
241	return free_all_bootmem_core(pgdat->bdata);
242}
243
244/**
245 * free_all_bootmem - release free pages to the buddy allocator
246 *
247 * Returns the number of pages actually released.
248 */
249unsigned long __init free_all_bootmem(void)
250{
251	unsigned long total_pages = 0;
252	bootmem_data_t *bdata;
253
254	list_for_each_entry(bdata, &bdata_list, list)
255		total_pages += free_all_bootmem_core(bdata);
256
257	return total_pages;
258}
259
260static void __init __free(bootmem_data_t *bdata,
261			unsigned long sidx, unsigned long eidx)
262{
263	unsigned long idx;
264
265	bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data,
266		sidx + bdata->node_min_pfn,
267		eidx + bdata->node_min_pfn);
268
269	if (bdata->hint_idx > sidx)
270		bdata->hint_idx = sidx;
271
272	for (idx = sidx; idx < eidx; idx++)
273		if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
274			BUG();
275}
276
277static int __init __reserve(bootmem_data_t *bdata, unsigned long sidx,
278			unsigned long eidx, int flags)
279{
280	unsigned long idx;
281	int exclusive = flags & BOOTMEM_EXCLUSIVE;
282
283	bdebug("nid=%td start=%lx end=%lx flags=%x\n",
284		bdata - bootmem_node_data,
285		sidx + bdata->node_min_pfn,
286		eidx + bdata->node_min_pfn,
287		flags);
288
289	for (idx = sidx; idx < eidx; idx++)
290		if (test_and_set_bit(idx, bdata->node_bootmem_map)) {
291			if (exclusive) {
292				__free(bdata, sidx, idx);
293				return -EBUSY;
294			}
295			bdebug("silent double reserve of PFN %lx\n",
296				idx + bdata->node_min_pfn);
297		}
298	return 0;
299}
300
301static int __init mark_bootmem_node(bootmem_data_t *bdata,
302				unsigned long start, unsigned long end,
303				int reserve, int flags)
304{
305	unsigned long sidx, eidx;
306
307	bdebug("nid=%td start=%lx end=%lx reserve=%d flags=%x\n",
308		bdata - bootmem_node_data, start, end, reserve, flags);
309
310	BUG_ON(start < bdata->node_min_pfn);
311	BUG_ON(end > bdata->node_low_pfn);
312
313	sidx = start - bdata->node_min_pfn;
314	eidx = end - bdata->node_min_pfn;
315
316	if (reserve)
317		return __reserve(bdata, sidx, eidx, flags);
318	else
319		__free(bdata, sidx, eidx);
320	return 0;
321}
322
323static int __init mark_bootmem(unsigned long start, unsigned long end,
324				int reserve, int flags)
325{
326	unsigned long pos;
327	bootmem_data_t *bdata;
328
329	pos = start;
330	list_for_each_entry(bdata, &bdata_list, list) {
331		int err;
332		unsigned long max;
333
334		if (pos < bdata->node_min_pfn ||
335		    pos >= bdata->node_low_pfn) {
336			BUG_ON(pos != start);
337			continue;
338		}
339
340		max = min(bdata->node_low_pfn, end);
341
342		err = mark_bootmem_node(bdata, pos, max, reserve, flags);
343		if (reserve && err) {
344			mark_bootmem(start, pos, 0, 0);
345			return err;
346		}
347
348		if (max == end)
349			return 0;
350		pos = bdata->node_low_pfn;
351	}
352	BUG();
353}
354
355/**
356 * free_bootmem_node - mark a page range as usable
357 * @pgdat: node the range resides on
358 * @physaddr: starting address of the range
359 * @size: size of the range in bytes
360 *
361 * Partial pages will be considered reserved and left as they are.
362 *
363 * The range must reside completely on the specified node.
364 */
365void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
366			      unsigned long size)
367{
368	unsigned long start, end;
369
370	kmemleak_free_part(__va(physaddr), size);
371
372	start = PFN_UP(physaddr);
373	end = PFN_DOWN(physaddr + size);
374
375	mark_bootmem_node(pgdat->bdata, start, end, 0, 0);
376}
377
378/**
379 * free_bootmem - mark a page range as usable
380 * @addr: starting address of the range
381 * @size: size of the range in bytes
382 *
383 * Partial pages will be considered reserved and left as they are.
384 *
385 * The range must be contiguous but may span node boundaries.
386 */
387void __init free_bootmem(unsigned long addr, unsigned long size)
388{
389	unsigned long start, end;
390
391	kmemleak_free_part(__va(addr), size);
392
393	start = PFN_UP(addr);
394	end = PFN_DOWN(addr + size);
395
396	mark_bootmem(start, end, 0, 0);
397}
398
399/**
400 * reserve_bootmem_node - mark a page range as reserved
401 * @pgdat: node the range resides on
402 * @physaddr: starting address of the range
403 * @size: size of the range in bytes
404 * @flags: reservation flags (see linux/bootmem.h)
405 *
406 * Partial pages will be reserved.
407 *
408 * The range must reside completely on the specified node.
409 */
410int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
411				 unsigned long size, int flags)
412{
413	unsigned long start, end;
414
415	start = PFN_DOWN(physaddr);
416	end = PFN_UP(physaddr + size);
417
418	return mark_bootmem_node(pgdat->bdata, start, end, 1, flags);
419}
420
421/**
422 * reserve_bootmem - mark a page range as usable
423 * @addr: starting address of the range
424 * @size: size of the range in bytes
425 * @flags: reservation flags (see linux/bootmem.h)
426 *
427 * Partial pages will be reserved.
428 *
429 * The range must be contiguous but may span node boundaries.
430 */
431int __init reserve_bootmem(unsigned long addr, unsigned long size,
432			    int flags)
433{
434	unsigned long start, end;
435
436	start = PFN_DOWN(addr);
437	end = PFN_UP(addr + size);
438
439	return mark_bootmem(start, end, 1, flags);
440}
441
442int __weak __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
443				   int flags)
444{
445	return reserve_bootmem(phys, len, flags);
446}
447
448static unsigned long __init align_idx(struct bootmem_data *bdata,
449				      unsigned long idx, unsigned long step)
450{
451	unsigned long base = bdata->node_min_pfn;
452
453	/*
454	 * Align the index with respect to the node start so that the
455	 * combination of both satisfies the requested alignment.
456	 */
457
458	return ALIGN(base + idx, step) - base;
459}
460
461static unsigned long __init align_off(struct bootmem_data *bdata,
462				      unsigned long off, unsigned long align)
463{
464	unsigned long base = PFN_PHYS(bdata->node_min_pfn);
465
466	/* Same as align_idx for byte offsets */
467
468	return ALIGN(base + off, align) - base;
469}
470
471static void * __init alloc_bootmem_bdata(struct bootmem_data *bdata,
472					unsigned long size, unsigned long align,
473					unsigned long goal, unsigned long limit)
474{
475	unsigned long fallback = 0;
476	unsigned long min, max, start, sidx, midx, step;
477
478	bdebug("nid=%td size=%lx [%lu pages] align=%lx goal=%lx limit=%lx\n",
479		bdata - bootmem_node_data, size, PAGE_ALIGN(size) >> PAGE_SHIFT,
480		align, goal, limit);
481
482	BUG_ON(!size);
483	BUG_ON(align & (align - 1));
484	BUG_ON(limit && goal + size > limit);
485
486	if (!bdata->node_bootmem_map)
487		return NULL;
488
489	min = bdata->node_min_pfn;
490	max = bdata->node_low_pfn;
491
492	goal >>= PAGE_SHIFT;
493	limit >>= PAGE_SHIFT;
494
495	if (limit && max > limit)
496		max = limit;
497	if (max <= min)
498		return NULL;
499
500	step = max(align >> PAGE_SHIFT, 1UL);
501
502	if (goal && min < goal && goal < max)
503		start = ALIGN(goal, step);
504	else
505		start = ALIGN(min, step);
506
507	sidx = start - bdata->node_min_pfn;
508	midx = max - bdata->node_min_pfn;
509
510	if (bdata->hint_idx > sidx) {
511		/*
512		 * Handle the valid case of sidx being zero and still
513		 * catch the fallback below.
514		 */
515		fallback = sidx + 1;
516		sidx = align_idx(bdata, bdata->hint_idx, step);
517	}
518
519	while (1) {
520		int merge;
521		void *region;
522		unsigned long eidx, i, start_off, end_off;
523find_block:
524		sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx);
525		sidx = align_idx(bdata, sidx, step);
526		eidx = sidx + PFN_UP(size);
527
528		if (sidx >= midx || eidx > midx)
529			break;
530
531		for (i = sidx; i < eidx; i++)
532			if (test_bit(i, bdata->node_bootmem_map)) {
533				sidx = align_idx(bdata, i, step);
534				if (sidx == i)
535					sidx += step;
536				goto find_block;
537			}
538
539		if (bdata->last_end_off & (PAGE_SIZE - 1) &&
540				PFN_DOWN(bdata->last_end_off) + 1 == sidx)
541			start_off = align_off(bdata, bdata->last_end_off, align);
542		else
543			start_off = PFN_PHYS(sidx);
544
545		merge = PFN_DOWN(start_off) < sidx;
546		end_off = start_off + size;
547
548		bdata->last_end_off = end_off;
549		bdata->hint_idx = PFN_UP(end_off);
550
551		/*
552		 * Reserve the area now:
553		 */
554		if (__reserve(bdata, PFN_DOWN(start_off) + merge,
555				PFN_UP(end_off), BOOTMEM_EXCLUSIVE))
556			BUG();
557
558		region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) +
559				start_off);
560		memset(region, 0, size);
561		/*
562		 * The min_count is set to 0 so that bootmem allocated blocks
563		 * are never reported as leaks.
564		 */
565		kmemleak_alloc(region, size, 0, 0);
566		return region;
567	}
568
569	if (fallback) {
570		sidx = align_idx(bdata, fallback - 1, step);
571		fallback = 0;
572		goto find_block;
573	}
574
575	return NULL;
576}
577
578static void * __init alloc_arch_preferred_bootmem(bootmem_data_t *bdata,
579					unsigned long size, unsigned long align,
580					unsigned long goal, unsigned long limit)
581{
582	if (WARN_ON_ONCE(slab_is_available()))
583		return kzalloc(size, GFP_NOWAIT);
584
585#ifdef CONFIG_HAVE_ARCH_BOOTMEM
586	{
587		bootmem_data_t *p_bdata;
588
589		p_bdata = bootmem_arch_preferred_node(bdata, size, align,
590							goal, limit);
591		if (p_bdata)
592			return alloc_bootmem_bdata(p_bdata, size, align,
593							goal, limit);
594	}
595#endif
596	return NULL;
597}
598
599static void * __init alloc_bootmem_core(unsigned long size,
600					unsigned long align,
601					unsigned long goal,
602					unsigned long limit)
603{
604	bootmem_data_t *bdata;
605	void *region;
606
607	region = alloc_arch_preferred_bootmem(NULL, size, align, goal, limit);
608	if (region)
609		return region;
610
611	list_for_each_entry(bdata, &bdata_list, list) {
612		if (goal && bdata->node_low_pfn <= PFN_DOWN(goal))
613			continue;
614		if (limit && bdata->node_min_pfn >= PFN_DOWN(limit))
615			break;
616
617		region = alloc_bootmem_bdata(bdata, size, align, goal, limit);
618		if (region)
619			return region;
620	}
621
622	return NULL;
623}
624
625static void * __init ___alloc_bootmem_nopanic(unsigned long size,
626					      unsigned long align,
627					      unsigned long goal,
628					      unsigned long limit)
629{
630	void *ptr;
631
632restart:
633	ptr = alloc_bootmem_core(size, align, goal, limit);
634	if (ptr)
635		return ptr;
636	if (goal) {
637		goal = 0;
638		goto restart;
639	}
640
641	return NULL;
642}
643
644/**
645 * __alloc_bootmem_nopanic - allocate boot memory without panicking
646 * @size: size of the request in bytes
647 * @align: alignment of the region
648 * @goal: preferred starting address of the region
649 *
650 * The goal is dropped if it can not be satisfied and the allocation will
651 * fall back to memory below @goal.
652 *
653 * Allocation may happen on any node in the system.
654 *
655 * Returns NULL on failure.
656 */
657void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
658					unsigned long goal)
659{
660	unsigned long limit = 0;
661
662	return ___alloc_bootmem_nopanic(size, align, goal, limit);
663}
664
665static void * __init ___alloc_bootmem(unsigned long size, unsigned long align,
666					unsigned long goal, unsigned long limit)
667{
668	void *mem = ___alloc_bootmem_nopanic(size, align, goal, limit);
669
670	if (mem)
671		return mem;
672	/*
673	 * Whoops, we cannot satisfy the allocation request.
674	 */
675	printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
676	panic("Out of memory");
677	return NULL;
678}
679
680/**
681 * __alloc_bootmem - allocate boot memory
682 * @size: size of the request in bytes
683 * @align: alignment of the region
684 * @goal: preferred starting address of the region
685 *
686 * The goal is dropped if it can not be satisfied and the allocation will
687 * fall back to memory below @goal.
688 *
689 * Allocation may happen on any node in the system.
690 *
691 * The function panics if the request can not be satisfied.
692 */
693void * __init __alloc_bootmem(unsigned long size, unsigned long align,
694			      unsigned long goal)
695{
696	unsigned long limit = 0;
697
698	return ___alloc_bootmem(size, align, goal, limit);
699}
700
701void * __init ___alloc_bootmem_node_nopanic(pg_data_t *pgdat,
702				unsigned long size, unsigned long align,
703				unsigned long goal, unsigned long limit)
704{
705	void *ptr;
706
707again:
708	ptr = alloc_arch_preferred_bootmem(pgdat->bdata, size,
709					   align, goal, limit);
710	if (ptr)
711		return ptr;
712
713	/* do not panic in alloc_bootmem_bdata() */
714	if (limit && goal + size > limit)
715		limit = 0;
716
717	ptr = alloc_bootmem_bdata(pgdat->bdata, size, align, goal, limit);
718	if (ptr)
719		return ptr;
720
721	ptr = alloc_bootmem_core(size, align, goal, limit);
722	if (ptr)
723		return ptr;
724
725	if (goal) {
726		goal = 0;
727		goto again;
728	}
729
730	return NULL;
731}
732
733void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size,
734				   unsigned long align, unsigned long goal)
735{
736	if (WARN_ON_ONCE(slab_is_available()))
737		return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
738
739	return ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
740}
741
742void * __init ___alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
743				    unsigned long align, unsigned long goal,
744				    unsigned long limit)
745{
746	void *ptr;
747
748	ptr = ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
749	if (ptr)
750		return ptr;
751
752	printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
753	panic("Out of memory");
754	return NULL;
755}
756
757/**
758 * __alloc_bootmem_node - allocate boot memory from a specific node
759 * @pgdat: node to allocate from
760 * @size: size of the request in bytes
761 * @align: alignment of the region
762 * @goal: preferred starting address of the region
763 *
764 * The goal is dropped if it can not be satisfied and the allocation will
765 * fall back to memory below @goal.
766 *
767 * Allocation may fall back to any node in the system if the specified node
768 * can not hold the requested memory.
769 *
770 * The function panics if the request can not be satisfied.
771 */
772void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
773				   unsigned long align, unsigned long goal)
774{
775	if (WARN_ON_ONCE(slab_is_available()))
776		return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
777
778	return  ___alloc_bootmem_node(pgdat, size, align, goal, 0);
779}
780
781void * __init __alloc_bootmem_node_high(pg_data_t *pgdat, unsigned long size,
782				   unsigned long align, unsigned long goal)
783{
784#ifdef MAX_DMA32_PFN
785	unsigned long end_pfn;
786
787	if (WARN_ON_ONCE(slab_is_available()))
788		return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
789
790	/* update goal according ...MAX_DMA32_PFN */
791	end_pfn = pgdat->node_start_pfn + pgdat->node_spanned_pages;
792
793	if (end_pfn > MAX_DMA32_PFN + (128 >> (20 - PAGE_SHIFT)) &&
794	    (goal >> PAGE_SHIFT) < MAX_DMA32_PFN) {
795		void *ptr;
796		unsigned long new_goal;
797
798		new_goal = MAX_DMA32_PFN << PAGE_SHIFT;
799		ptr = alloc_bootmem_bdata(pgdat->bdata, size, align,
800						 new_goal, 0);
801		if (ptr)
802			return ptr;
803	}
804#endif
805
806	return __alloc_bootmem_node(pgdat, size, align, goal);
807
808}
809
810#ifndef ARCH_LOW_ADDRESS_LIMIT
811#define ARCH_LOW_ADDRESS_LIMIT	0xffffffffUL
812#endif
813
814/**
815 * __alloc_bootmem_low - allocate low boot memory
816 * @size: size of the request in bytes
817 * @align: alignment of the region
818 * @goal: preferred starting address of the region
819 *
820 * The goal is dropped if it can not be satisfied and the allocation will
821 * fall back to memory below @goal.
822 *
823 * Allocation may happen on any node in the system.
824 *
825 * The function panics if the request can not be satisfied.
826 */
827void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
828				  unsigned long goal)
829{
830	return ___alloc_bootmem(size, align, goal, ARCH_LOW_ADDRESS_LIMIT);
831}
832
833/**
834 * __alloc_bootmem_low_node - allocate low boot memory from a specific node
835 * @pgdat: node to allocate from
836 * @size: size of the request in bytes
837 * @align: alignment of the region
838 * @goal: preferred starting address of the region
839 *
840 * The goal is dropped if it can not be satisfied and the allocation will
841 * fall back to memory below @goal.
842 *
843 * Allocation may fall back to any node in the system if the specified node
844 * can not hold the requested memory.
845 *
846 * The function panics if the request can not be satisfied.
847 */
848void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
849				       unsigned long align, unsigned long goal)
850{
851	if (WARN_ON_ONCE(slab_is_available()))
852		return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
853
854	return ___alloc_bootmem_node(pgdat, size, align,
855				     goal, ARCH_LOW_ADDRESS_LIMIT);
856}