/* * sparse memory mappings. */#include <linux/config.h>#include <linux/mm.h>#include <linux/mmzone.h>#include <linux/bootmem.h>#include <linux/module.h>#include <asm/dma.h> /* * Permanent SPARSEMEM data: * * 1) mem_section	- memory sections, mem_map's for valid memory */struct mem_section mem_section[NR_MEM_SECTIONS];EXPORT_SYMBOL(mem_section); /* 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);		if (!mem_section[section].section_mem_map)			mem_section[section].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)); 	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__);	mem_section[pnum].section_mem_map = 0;	return NULL;} /* * 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)			sparse_init_one_section(&mem_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(unsigned long start_pfn, int nr_pages, struct page *map){	struct mem_section *ms = __pfn_to_section(start_pfn); 	if (ms->section_mem_map & SECTION_MARKED_PRESENT)		return -EEXIST; 	ms->section_mem_map |= SECTION_MARKED_PRESENT; 	return sparse_init_one_section(ms, pfn_to_section_nr(start_pfn), map);}