/*
 * sparse memory mappings.
 */
#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_EXTREME
struct mem_section *mem_section[NR_SECTION_ROOTS]
        ____cacheline_internodealigned_in_smp;
#else
struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]
        ____cacheline_internodealigned_in_smp;
#endif
EXPORT_SYMBOL(mem_section);

#ifdef NODE_NOT_IN_PAGE_FLAGS
/*
 * If we did not store the node number in the page then we have to
 * do a lookup in the section_to_node_table in order to find which
 * node the page belongs to.
 */
#if MAX_NUMNODES <= 256
static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
#else
static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned;
#endif

int page_to_nid(struct page *page)
{
        return section_to_node_table[page_to_section(page)];
}
EXPORT_SYMBOL(page_to_nid);
#endif

#ifdef CONFIG_SPARSEMEM_EXTREME
static struct mem_section noinline __init_refok *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 __meminit sparse_index_init(unsigned long section_nr, int nid)
{
        static DEFINE_SPINLOCK(index_init_lock);
        unsigned long root = SECTION_NR_TO_ROOT(section_nr);
        struct mem_section *section;
        int ret = 0;

#ifdef NODE_NOT_IN_PAGE_FLAGS
        section_to_node_table[section_nr] = nid;
#endif

        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);
}

/*
 * During early boot, before section_mem_map is used for an actual
 * mem_map, we use section_mem_map to store the section's NUMA
 * node.  This keeps us from having to use another data structure.  The
 * node information is cleared just before we store the real mem_map.
 */
static inline unsigned long sparse_encode_early_nid(int nid)
{
        return (nid << SECTION_NID_SHIFT);
}

static inline int sparse_early_nid(struct mem_section *section)
{
        return (section->section_mem_map >> SECTION_NID_SHIFT);
}

/* Record a memory area against a node. */
void __init 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 = sparse_encode_early_nid(nid) |
                                                        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 __meminit 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 &= ~SECTION_MAP_MASK;
        ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum);

        return 1;
}

static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
{
        struct page *map;
        struct mem_section *ms = __nr_to_section(pnum);
        int nid = sparse_early_nid(ms);

        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;
}

/*
 * Allocate the accumulated non-linear sections, allocate a mem_map
 * for each and record the physical to section mapping.
 */
void __init 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);
        }
}

#ifdef CONFIG_MEMORY_HOTPLUG
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|__GFP_NOWARN, 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));
}

/*
 * 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;
}
#endif