/* * Virtual Memory Map support * * (C) 2007 sgi. Christoph Lameter. * * Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn, * virt_to_page, page_address() to be implemented as a base offset * calculation without memory access. * * However, virtual mappings need a page table and TLBs. Many Linux * architectures already map their physical space using 1-1 mappings * via TLBs. For those arches the virtual memory map is essentially * for free if we use the same page size as the 1-1 mappings. In that * case the overhead consists of a few additional pages that are * allocated to create a view of memory for vmemmap. * * The architecture is expected to provide a vmemmap_populate() function * to instantiate the mapping. */#include <linux/mm.h>#include <linux/mmzone.h>#include <linux/bootmem.h>#include <linux/highmem.h>#include <linux/slab.h>#include <linux/spinlock.h>#include <linux/vmalloc.h>#include <linux/sched.h>#include <asm/dma.h>#include <asm/pgalloc.h>#include <asm/pgtable.h> /* * Allocate a block of memory to be used to back the virtual memory map * or to back the page tables that are used to create the mapping. * Uses the main allocators if they are available, else bootmem. */ static void * __init_refok __earlyonly_bootmem_alloc(int node,				unsigned long size,				unsigned long align,				unsigned long goal){	return __alloc_bootmem_node_high(NODE_DATA(node), size, align, goal);} static void *vmemmap_buf;static void *vmemmap_buf_end; void * __meminit vmemmap_alloc_block(unsigned long size, int node){	/* If the main allocator is up use that, fallback to bootmem. */	if (slab_is_available()) {		struct page *page; 		if (node_state(node, N_HIGH_MEMORY))			page = alloc_pages_node(				node, GFP_KERNEL | __GFP_ZERO | __GFP_REPEAT,				get_order(size));		else			page = alloc_pages(				GFP_KERNEL | __GFP_ZERO | __GFP_REPEAT,				get_order(size));		if (page)			return page_address(page);		return NULL;	} else		return __earlyonly_bootmem_alloc(node, size, size,				__pa(MAX_DMA_ADDRESS));} /* need to make sure size is all the same during early stage */void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node){	void *ptr; 	if (!vmemmap_buf)		return vmemmap_alloc_block(size, node); 	/* take the from buf */	ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size);	if (ptr + size > vmemmap_buf_end)		return vmemmap_alloc_block(size, node); 	vmemmap_buf = ptr + size; 	return ptr;} void __meminit vmemmap_verify(pte_t *pte, int node,				unsigned long start, unsigned long end){	unsigned long pfn = pte_pfn(*pte);	int actual_node = early_pfn_to_nid(pfn); 	if (node_distance(actual_node, node) > LOCAL_DISTANCE)		printk(KERN_WARNING "[%lx-%lx] potential offnode "			"page_structs\n", start, end - 1);} pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node){	pte_t *pte = pte_offset_kernel(pmd, addr);	if (pte_none(*pte)) {		pte_t entry;		void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node);		if (!p)			return NULL;		entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);		set_pte_at(&init_mm, addr, pte, entry);	}	return pte;} pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node){	pmd_t *pmd = pmd_offset(pud, addr);	if (pmd_none(*pmd)) {		void *p = vmemmap_alloc_block(PAGE_SIZE, node);		if (!p)			return NULL;		pmd_populate_kernel(&init_mm, pmd, p);	}	return pmd;} pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node){	pud_t *pud = pud_offset(pgd, addr);	if (pud_none(*pud)) {		void *p = vmemmap_alloc_block(PAGE_SIZE, node);		if (!p)			return NULL;		pud_populate(&init_mm, pud, p);	}	return pud;} pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node){	pgd_t *pgd = pgd_offset_k(addr);	if (pgd_none(*pgd)) {		void *p = vmemmap_alloc_block(PAGE_SIZE, node);		if (!p)			return NULL;		pgd_populate(&init_mm, pgd, p);	}	return pgd;} int __meminit vmemmap_populate_basepages(unsigned long start,					 unsigned long end, int node){	unsigned long addr = start;	pgd_t *pgd;	pud_t *pud;	pmd_t *pmd;	pte_t *pte; 	for (; addr < end; addr += PAGE_SIZE) {		pgd = vmemmap_pgd_populate(addr, node);		if (!pgd)			return -ENOMEM;		pud = vmemmap_pud_populate(pgd, addr, node);		if (!pud)			return -ENOMEM;		pmd = vmemmap_pmd_populate(pud, addr, node);		if (!pmd)			return -ENOMEM;		pte = vmemmap_pte_populate(pmd, addr, node);		if (!pte)			return -ENOMEM;		vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);	} 	return 0;} struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid){	unsigned long start;	unsigned long end;	struct page *map; 	map = pfn_to_page(pnum * PAGES_PER_SECTION);	start = (unsigned long)map;	end = (unsigned long)(map + PAGES_PER_SECTION); 	if (vmemmap_populate(start, end, nid))		return NULL; 	return map;} void __init sparse_mem_maps_populate_node(struct page **map_map,					  unsigned long pnum_begin,					  unsigned long pnum_end,					  unsigned long map_count, int nodeid){	unsigned long pnum;	unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;	void *vmemmap_buf_start; 	size = ALIGN(size, PMD_SIZE);	vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count,			 PMD_SIZE, __pa(MAX_DMA_ADDRESS)); 	if (vmemmap_buf_start) {		vmemmap_buf = vmemmap_buf_start;		vmemmap_buf_end = vmemmap_buf_start + size * map_count;	} 	for (pnum = pnum_begin; pnum < pnum_end; pnum++) {		struct mem_section *ms; 		if (!present_section_nr(pnum))			continue; 		map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);		if (map_map[pnum])			continue;		ms = __nr_to_section(pnum);		printk(KERN_ERR "%s: sparsemem memory map backing failed "			"some memory will not be available.\n", __func__);		ms->section_mem_map = 0;	} 	if (vmemmap_buf_start) {		/* need to free left buf */		free_bootmem(__pa(vmemmap_buf), vmemmap_buf_end - vmemmap_buf);		vmemmap_buf = NULL;		vmemmap_buf_end = NULL;	}}