/* *  linux/mm/bootmem.c * *  Copyright (C) 1999 Ingo Molnar *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999 * *  simple boot-time physical memory area allocator and *  free memory collector. It's used to deal with reserved *  system memory and memory holes as well. */ #include <linux/mm.h>#include <linux/kernel_stat.h>#include <linux/swap.h>#include <linux/interrupt.h>#include <linux/init.h>#include <linux/bootmem.h>#include <linux/mmzone.h>#include <linux/module.h>#include <asm/dma.h>#include <asm/io.h>#include "internal.h" /* * Access to this subsystem has to be serialized externally. (this is * true for the boot process anyway) */unsigned long max_low_pfn;unsigned long min_low_pfn;unsigned long max_pfn; EXPORT_SYMBOL(max_pfn);		/* This is exported so				 * dma_get_required_mask(), which uses				 * it, can be an inline function */ static LIST_HEAD(bdata_list);#ifdef CONFIG_CRASH_DUMP/* * If we have booted due to a crash, max_pfn will be a very low value. We need * to know the amount of memory that the previous kernel used. */unsigned long saved_max_pfn;#endif /* return the number of _pages_ that will be allocated for the boot bitmap */unsigned long __init bootmem_bootmap_pages (unsigned long pages){	unsigned long mapsize; 	mapsize = (pages+7)/8;	mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;	mapsize >>= PAGE_SHIFT; 	return mapsize;}/* * link bdata in order */static void link_bootmem(bootmem_data_t *bdata){	bootmem_data_t *ent;	if (list_empty(&bdata_list)) {		list_add(&bdata->list, &bdata_list);		return;	}	/* insert in order */	list_for_each_entry(ent, &bdata_list, list) {		if (bdata->node_boot_start < ent->node_boot_start) {			list_add_tail(&bdata->list, &ent->list);			return;		}	}	list_add_tail(&bdata->list, &bdata_list);	return;}  /* * Called once to set up the allocator itself. */static unsigned long __init init_bootmem_core (pg_data_t *pgdat,	unsigned long mapstart, unsigned long start, unsigned long end){	bootmem_data_t *bdata = pgdat->bdata;	unsigned long mapsize = ((end - start)+7)/8; 	mapsize = ALIGN(mapsize, sizeof(long));	bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);	bdata->node_boot_start = (start << PAGE_SHIFT);	bdata->node_low_pfn = end;	link_bootmem(bdata); 	/*	 * Initially all pages are reserved - setup_arch() has to	 * register free RAM areas explicitly.	 */	memset(bdata->node_bootmem_map, 0xff, mapsize); 	return mapsize;} /* * Marks a particular physical memory range as unallocatable. Usable RAM * might be used for boot-time allocations - or it might get added * to the free page pool later on. */static void __init reserve_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size){	unsigned long i;	/*	 * round up, partially reserved pages are considered	 * fully reserved.	 */	unsigned long sidx = (addr - bdata->node_boot_start)/PAGE_SIZE;	unsigned long eidx = (addr + size - bdata->node_boot_start + 							PAGE_SIZE-1)/PAGE_SIZE;	unsigned long end = (addr + size + PAGE_SIZE-1)/PAGE_SIZE; 	BUG_ON(!size);	BUG_ON(sidx >= eidx);	BUG_ON((addr >> PAGE_SHIFT) >= bdata->node_low_pfn);	BUG_ON(end > bdata->node_low_pfn); 	for (i = sidx; i < eidx; i++)		if (test_and_set_bit(i, bdata->node_bootmem_map)) {#ifdef CONFIG_DEBUG_BOOTMEM			printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);#endif		}} static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr, unsigned long size){	unsigned long i;	unsigned long start;	/*	 * round down end of usable mem, partially free pages are	 * considered reserved.	 */	unsigned long sidx;	unsigned long eidx = (addr + size - bdata->node_boot_start)/PAGE_SIZE;	unsigned long end = (addr + size)/PAGE_SIZE; 	BUG_ON(!size);	BUG_ON(end > bdata->node_low_pfn); 	if (addr < bdata->last_success)		bdata->last_success = addr; 	/*	 * Round up the beginning of the address.	 */	start = (addr + PAGE_SIZE-1) / PAGE_SIZE;	sidx = start - (bdata->node_boot_start/PAGE_SIZE); 	for (i = sidx; i < eidx; i++) {		if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))			BUG();	}} /* * We 'merge' subsequent allocations to save space. We might 'lose' * some fraction of a page if allocations cannot be satisfied due to * size constraints on boxes where there is physical RAM space * fragmentation - in these cases (mostly large memory boxes) this * is not a problem. * * On low memory boxes we get it right in 100% of the cases. * * alignment has to be a power of 2 value. * * NOTE:  This function is _not_ reentrant. */void * __init__alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,	      unsigned long align, unsigned long goal, unsigned long limit){	unsigned long offset, remaining_size, areasize, preferred;	unsigned long i, start = 0, incr, eidx, end_pfn = bdata->node_low_pfn;	void *ret; 	if(!size) {		printk("__alloc_bootmem_core(): zero-sized request\n");		BUG();	}	BUG_ON(align & (align-1)); 	if (limit && bdata->node_boot_start >= limit)		return NULL;         limit >>=PAGE_SHIFT;	if (limit && end_pfn > limit)		end_pfn = limit; 	eidx = end_pfn - (bdata->node_boot_start >> PAGE_SHIFT);	offset = 0;	if (align &&	    (bdata->node_boot_start & (align - 1UL)) != 0)		offset = (align - (bdata->node_boot_start & (align - 1UL)));	offset >>= PAGE_SHIFT; 	/*	 * We try to allocate bootmem pages above 'goal'	 * first, then we try to allocate lower pages.	 */	if (goal && (goal >= bdata->node_boot_start) && 	    ((goal >> PAGE_SHIFT) < end_pfn)) {		preferred = goal - bdata->node_boot_start; 		if (bdata->last_success >= preferred)			if (!limit || (limit && limit > bdata->last_success))				preferred = bdata->last_success;	} else		preferred = 0; 	preferred = ALIGN(preferred, align) >> PAGE_SHIFT;	preferred += offset;	areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;	incr = align >> PAGE_SHIFT ? : 1; restart_scan:	for (i = preferred; i < eidx; i += incr) {		unsigned long j;		i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);		i = ALIGN(i, incr);		if (i >= eidx)			break;		if (test_bit(i, bdata->node_bootmem_map))			continue;		for (j = i + 1; j < i + areasize; ++j) {			if (j >= eidx)				goto fail_block;			if (test_bit (j, bdata->node_bootmem_map))				goto fail_block;		}		start = i;		goto found;	fail_block:		i = ALIGN(j, incr);	} 	if (preferred > offset) {		preferred = offset;		goto restart_scan;	}	return NULL; found:	bdata->last_success = start << PAGE_SHIFT;	BUG_ON(start >= eidx); 	/*	 * Is the next page of the previous allocation-end the start	 * of this allocation's buffer? If yes then we can 'merge'	 * the previous partial page with this allocation.	 */	if (align < PAGE_SIZE &&	    bdata->last_offset && bdata->last_pos+1 == start) {		offset = ALIGN(bdata->last_offset, align);		BUG_ON(offset > PAGE_SIZE);		remaining_size = PAGE_SIZE-offset;		if (size < remaining_size) {			areasize = 0;			/* last_pos unchanged */			bdata->last_offset = offset+size;			ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +						bdata->node_boot_start);		} else {			remaining_size = size - remaining_size;			areasize = (remaining_size+PAGE_SIZE-1)/PAGE_SIZE;			ret = phys_to_virt(bdata->last_pos*PAGE_SIZE + offset +						bdata->node_boot_start);			bdata->last_pos = start+areasize-1;			bdata->last_offset = remaining_size;		}		bdata->last_offset &= ~PAGE_MASK;	} else {		bdata->last_pos = start + areasize - 1;		bdata->last_offset = size & ~PAGE_MASK;		ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);	} 	/*	 * Reserve the area now:	 */	for (i = start; i < start+areasize; i++)		if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))			BUG();	memset(ret, 0, size);	return ret;} static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat){	struct page *page;	unsigned long pfn;	bootmem_data_t *bdata = pgdat->bdata;	unsigned long i, count, total = 0;	unsigned long idx;	unsigned long *map; 	int gofast = 0; 	BUG_ON(!bdata->node_bootmem_map); 	count = 0;	/* first extant page of the node */	pfn = bdata->node_boot_start >> PAGE_SHIFT;	idx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT);	map = bdata->node_bootmem_map;	/* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */	if (bdata->node_boot_start == 0 ||	    ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))		gofast = 1;	for (i = 0; i < idx; ) {		unsigned long v = ~map[i / BITS_PER_LONG]; 		if (gofast && v == ~0UL) {			int order; 			page = pfn_to_page(pfn);			count += BITS_PER_LONG;			order = ffs(BITS_PER_LONG) - 1;			__free_pages_bootmem(page, order);			i += BITS_PER_LONG;			page += BITS_PER_LONG;		} else if (v) {			unsigned long m; 			page = pfn_to_page(pfn);			for (m = 1; m && i < idx; m<<=1, page++, i++) {				if (v & m) {					count++;					__free_pages_bootmem(page, 0);				}			}		} else {			i+=BITS_PER_LONG;		}		pfn += BITS_PER_LONG;	}	total += count; 	/*	 * Now free the allocator bitmap itself, it's not	 * needed anymore:	 */	page = virt_to_page(bdata->node_bootmem_map);	count = 0;	for (i = 0; i < ((bdata->node_low_pfn-(bdata->node_boot_start >> PAGE_SHIFT))/8 + PAGE_SIZE-1)/PAGE_SIZE; i++,page++) {		count++;		__free_pages_bootmem(page, 0);	}	total += count;	bdata->node_bootmem_map = NULL; 	return total;} unsigned long __init init_bootmem_node (pg_data_t *pgdat, unsigned long freepfn, unsigned long startpfn, unsigned long endpfn){	return(init_bootmem_core(pgdat, freepfn, startpfn, endpfn));} void __init reserve_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size){	reserve_bootmem_core(pgdat->bdata, physaddr, size);} void __init free_bootmem_node (pg_data_t *pgdat, unsigned long physaddr, unsigned long size){	free_bootmem_core(pgdat->bdata, physaddr, size);} unsigned long __init free_all_bootmem_node (pg_data_t *pgdat){	return(free_all_bootmem_core(pgdat));} unsigned long __init init_bootmem (unsigned long start, unsigned long pages){	max_low_pfn = pages;	min_low_pfn = start;	return(init_bootmem_core(NODE_DATA(0), start, 0, pages));} #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODEvoid __init reserve_bootmem (unsigned long addr, unsigned long size){	reserve_bootmem_core(NODE_DATA(0)->bdata, addr, size);}#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */ void __init free_bootmem (unsigned long addr, unsigned long size){	free_bootmem_core(NODE_DATA(0)->bdata, addr, size);} unsigned long __init free_all_bootmem (void){	return(free_all_bootmem_core(NODE_DATA(0)));} void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align, unsigned long goal){	bootmem_data_t *bdata;	void *ptr; 	list_for_each_entry(bdata, &bdata_list, list)		if ((ptr = __alloc_bootmem_core(bdata, size, align, goal, 0)))			return(ptr);	return NULL;} void * __init __alloc_bootmem(unsigned long size, unsigned long align, unsigned long goal){	void *mem = __alloc_bootmem_nopanic(size,align,goal);	if (mem)		return mem;	/*	 * Whoops, we cannot satisfy the allocation request.	 */	printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);	panic("Out of memory");	return NULL;}  void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size, unsigned long align,				   unsigned long goal){	void *ptr; 	ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);	if (ptr)		return (ptr); 	return __alloc_bootmem(size, align, goal);} #define LOW32LIMIT 0xffffffff void * __init __alloc_bootmem_low(unsigned long size, unsigned long align, unsigned long goal){	bootmem_data_t *bdata;	void *ptr; 	list_for_each_entry(bdata, &bdata_list, list)		if ((ptr = __alloc_bootmem_core(bdata, size,						 align, goal, LOW32LIMIT)))			return(ptr); 	/*	 * Whoops, we cannot satisfy the allocation request.	 */	printk(KERN_ALERT "low bootmem alloc of %lu bytes failed!\n", size);	panic("Out of low memory");	return NULL;} void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,				       unsigned long align, unsigned long goal){	return __alloc_bootmem_core(pgdat->bdata, size, align, goal, LOW32LIMIT);}