/* * sparse memory mappings. */#include <linux/config.h>#include <linux/mm.h>#include <linux/mmzone.h>#include <linux/bootmem.h>#include <linux/highmem.h>#include <linux/module.h>#include <linux/spinlock.h>#include <linux/vmalloc.h>#include <asm/dma.h> /* * Permanent SPARSEMEM data: * * 1) mem_section	- memory sections, mem_map's for valid memory */#ifdef CONFIG_SPARSEMEM_EXTREMEstruct mem_section *mem_section[NR_SECTION_ROOTS]	____cacheline_internodealigned_in_smp;#elsestruct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]	____cacheline_internodealigned_in_smp;#endifEXPORT_SYMBOL(mem_section); #ifdef CONFIG_SPARSEMEM_EXTREMEstatic struct mem_section *sparse_index_alloc(int nid){	struct mem_section *section = NULL;	unsigned long array_size = SECTIONS_PER_ROOT *				   sizeof(struct mem_section); 	if (slab_is_available())		section = kmalloc_node(array_size, GFP_KERNEL, nid);	else		section = alloc_bootmem_node(NODE_DATA(nid), array_size); 	if (section)		memset(section, 0, array_size); 	return section;} static int sparse_index_init(unsigned long section_nr, int nid){	static spinlock_t index_init_lock = SPIN_LOCK_UNLOCKED;	unsigned long root = SECTION_NR_TO_ROOT(section_nr);	struct mem_section *section;	int ret = 0; 	if (mem_section[root])		return -EEXIST; 	section = sparse_index_alloc(nid);	/*	 * This lock keeps two different sections from	 * reallocating for the same index	 */	spin_lock(&index_init_lock); 	if (mem_section[root]) {		ret = -EEXIST;		goto out;	} 	mem_section[root] = section;out:	spin_unlock(&index_init_lock);	return ret;}#else /* !SPARSEMEM_EXTREME */static inline int sparse_index_init(unsigned long section_nr, int nid){	return 0;}#endif /* * Although written for the SPARSEMEM_EXTREME case, this happens * to also work for the flat array case becase * NR_SECTION_ROOTS==NR_MEM_SECTIONS. */int __section_nr(struct mem_section* ms){	unsigned long root_nr;	struct mem_section* root; 	for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) {		root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);		if (!root)			continue; 		if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT)))		     break;	} 	return (root_nr * SECTIONS_PER_ROOT) + (ms - root);} /* Record a memory area against a node. */void memory_present(int nid, unsigned long start, unsigned long end){	unsigned long pfn; 	start &= PAGE_SECTION_MASK;	for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {		unsigned long section = pfn_to_section_nr(pfn);		struct mem_section *ms; 		sparse_index_init(section, nid); 		ms = __nr_to_section(section);		if (!ms->section_mem_map)			ms->section_mem_map = SECTION_MARKED_PRESENT;	}} /* * Only used by the i386 NUMA architecures, but relatively * generic code. */unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn,						     unsigned long end_pfn){	unsigned long pfn;	unsigned long nr_pages = 0; 	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {		if (nid != early_pfn_to_nid(pfn))			continue; 		if (pfn_valid(pfn))			nr_pages += PAGES_PER_SECTION;	} 	return nr_pages * sizeof(struct page);} /* * Subtle, we encode the real pfn into the mem_map such that * the identity pfn - section_mem_map will return the actual * physical page frame number. */static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum){	return (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));} /* * We need this if we ever free the mem_maps.  While not implemented yet, * this function is included for parity with its sibling. */static __attribute((unused))struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum){	return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);} static int sparse_init_one_section(struct mem_section *ms,		unsigned long pnum, struct page *mem_map){	if (!valid_section(ms))		return -EINVAL; 	ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum); 	return 1;} static struct page *sparse_early_mem_map_alloc(unsigned long pnum){	struct page *map;	int nid = early_pfn_to_nid(section_nr_to_pfn(pnum));	struct mem_section *ms = __nr_to_section(pnum); 	map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);	if (map)		return map; 	map = alloc_bootmem_node(NODE_DATA(nid),			sizeof(struct page) * PAGES_PER_SECTION);	if (map)		return map; 	printk(KERN_WARNING "%s: allocation failed\n", __FUNCTION__);	ms->section_mem_map = 0;	return NULL;} static struct page *__kmalloc_section_memmap(unsigned long nr_pages){	struct page *page, *ret;	unsigned long memmap_size = sizeof(struct page) * nr_pages; 	page = alloc_pages(GFP_KERNEL, get_order(memmap_size));	if (page)		goto got_map_page; 	ret = vmalloc(memmap_size);	if (ret)		goto got_map_ptr; 	return NULL;got_map_page:	ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));got_map_ptr:	memset(ret, 0, memmap_size); 	return ret;} static int vaddr_in_vmalloc_area(void *addr){	if (addr >= (void *)VMALLOC_START &&	    addr < (void *)VMALLOC_END)		return 1;	return 0;} static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages){	if (vaddr_in_vmalloc_area(memmap))		vfree(memmap);	else		free_pages((unsigned long)memmap,			   get_order(sizeof(struct page) * nr_pages));} /* * Allocate the accumulated non-linear sections, allocate a mem_map * for each and record the physical to section mapping. */void sparse_init(void){	unsigned long pnum;	struct page *map; 	for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {		if (!valid_section_nr(pnum))			continue; 		map = sparse_early_mem_map_alloc(pnum);		if (!map)			continue;		sparse_init_one_section(__nr_to_section(pnum), pnum, map);	}} /* * returns the number of sections whose mem_maps were properly * set.  If this is <=0, then that means that the passed-in * map was not consumed and must be freed. */int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,			   int nr_pages){	unsigned long section_nr = pfn_to_section_nr(start_pfn);	struct pglist_data *pgdat = zone->zone_pgdat;	struct mem_section *ms;	struct page *memmap;	unsigned long flags;	int ret; 	/*	 * no locking for this, because it does its own	 * plus, it does a kmalloc	 */	sparse_index_init(section_nr, pgdat->node_id);	memmap = __kmalloc_section_memmap(nr_pages); 	pgdat_resize_lock(pgdat, &flags); 	ms = __pfn_to_section(start_pfn);	if (ms->section_mem_map & SECTION_MARKED_PRESENT) {		ret = -EEXIST;		goto out;	}	ms->section_mem_map |= SECTION_MARKED_PRESENT; 	ret = sparse_init_one_section(ms, section_nr, memmap); out:	pgdat_resize_unlock(pgdat, &flags);	if (ret <= 0)		__kfree_section_memmap(memmap, nr_pages);	return ret;}