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/*
* sparse memory mappings.
*/
#include <linux/mm.h>
#include <linux/slab.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 "internal.h"
#include <asm/dma.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.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);

static void set_section_nid(unsigned long section_nr, int nid)
{
section_to_node_table[section_nr] = nid;
}
#else /* !NODE_NOT_IN_PAGE_FLAGS */
static inline void set_section_nid(unsigned long section_nr, int 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()) {
if (node_state(nid, N_HIGH_MEMORY))
section = kmalloc_node(array_size, GFP_KERNEL, nid);
else
section = kmalloc(array_size, GFP_KERNEL);
} 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;

if (mem_section[root])
return -EEXIST;

section = sparse_index_alloc(nid);
if (!section)
return -ENOMEM;
/*
* 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 because
* 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);
}

/* Validate the physical addressing limitations of the model */
void __meminit mminit_validate_memmodel_limits(unsigned long *start_pfn,
unsigned long *end_pfn)
{
unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);

/*
* Sanity checks - do not allow an architecture to pass
* in larger pfns than the maximum scope of sparsemem:
*/
if (*start_pfn > max_sparsemem_pfn) {
mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
"Start of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
*start_pfn, *end_pfn, max_sparsemem_pfn);
WARN_ON_ONCE(1);
*start_pfn = max_sparsemem_pfn;
*end_pfn = max_sparsemem_pfn;
} else if (*end_pfn > max_sparsemem_pfn) {
mminit_dprintk(MMINIT_WARNING, "pfnvalidation",
"End of range %lu -> %lu exceeds SPARSEMEM max %lu\n",
*start_pfn, *end_pfn, max_sparsemem_pfn);
WARN_ON_ONCE(1);
*end_pfn = max_sparsemem_pfn;
}
}

/* 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;
mminit_validate_memmodel_limits(&start, &end);
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);
set_section_nid(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;

mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
if (nid != early_pfn_to_nid(pfn))
continue;

if (pfn_present(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)));
}

/*
* Decode mem_map from the coded memmap
*/
struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
{
/* mask off the extra low bits of information */
coded_mem_map &= SECTION_MAP_MASK;
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,
unsigned long *pageblock_bitmap)
{
if (!present_section(ms))
return -EINVAL;

ms->section_mem_map &= ~SECTION_MAP_MASK;
ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum) |
SECTION_HAS_MEM_MAP;
  ms->pageblock_flags = pageblock_bitmap;

return 1;
}

unsigned long usemap_size(void)
{
unsigned long size_bytes;
size_bytes = roundup(SECTION_BLOCKFLAGS_BITS, 8) / 8;
size_bytes = roundup(size_bytes, sizeof(unsigned long));
return size_bytes;
}

#ifdef CONFIG_MEMORY_HOTPLUG
static unsigned long *__kmalloc_section_usemap(void)
{
return kmalloc(usemap_size(), GFP_KERNEL);
}
#endif /* CONFIG_MEMORY_HOTPLUG */

#ifdef CONFIG_MEMORY_HOTREMOVE
static unsigned long * __init
sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
unsigned long count)
{
unsigned long section_nr;

/*
* A page may contain usemaps for other sections preventing the
* page being freed and making a section unremovable while
* other sections referencing the usemap retmain active. Similarly,
* a pgdat can prevent a section being removed. If section A
* contains a pgdat and section B contains the usemap, both
* sections become inter-dependent. This allocates usemaps
* from the same section as the pgdat where possible to avoid
* this problem.
*/
section_nr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
return alloc_bootmem_section(usemap_size() * count, section_nr);
}

static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
{
unsigned long usemap_snr, pgdat_snr;
static unsigned long old_usemap_snr = NR_MEM_SECTIONS;
static unsigned long old_pgdat_snr = NR_MEM_SECTIONS;
struct pglist_data *pgdat = NODE_DATA(nid);
int usemap_nid;

usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT);
pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT);
if (usemap_snr == pgdat_snr)
return;

if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr)
/* skip redundant message */
return;

old_usemap_snr = usemap_snr;
old_pgdat_snr = pgdat_snr;

usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr));
if (usemap_nid != nid) {
printk(KERN_INFO
"node %d must be removed before remove section %ld\n",
nid, usemap_snr);
return;
}
/*
* There is a circular dependency.
* Some platforms allow un-removable section because they will just
* gather other removable sections for dynamic partitioning.
* Just notify un-removable section's number here.
*/
printk(KERN_INFO "Section %ld and %ld (node %d)", usemap_snr,
pgdat_snr, nid);
printk(KERN_CONT
" have a circular dependency on usemap and pgdat allocations\n");
}
#else
static unsigned long * __init
sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
unsigned long count)
{
return NULL;
}

static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
{
}
#endif /* CONFIG_MEMORY_HOTREMOVE */

static void __init sparse_early_usemaps_alloc_node(unsigned long**usemap_map,
unsigned long pnum_begin,
unsigned long pnum_end,
unsigned long usemap_count, int nodeid)
{
void *usemap;
unsigned long pnum;
int size = usemap_size();

usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
usemap_count);
if (usemap) {
for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
if (!present_section_nr(pnum))
continue;
usemap_map[pnum] = usemap;
usemap += size;
}
return;
}

usemap = alloc_bootmem_node(NODE_DATA(nodeid), size * usemap_count);
if (usemap) {
for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
if (!present_section_nr(pnum))
continue;
usemap_map[pnum] = usemap;
usemap += size;
check_usemap_section_nr(nodeid, usemap_map[pnum]);
}
return;
}

printk(KERN_WARNING "%s: allocation failed\n", __func__);
}

#ifndef CONFIG_SPARSEMEM_VMEMMAP
struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid)
{
struct page *map;
unsigned long size;

map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
if (map)
return map;

size = PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
map = __alloc_bootmem_node_high(NODE_DATA(nid), size,
PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
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)
{
void *map;
unsigned long pnum;
unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;

map = alloc_remap(nodeid, size * map_count);
if (map) {
for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
if (!present_section_nr(pnum))
continue;
map_map[pnum] = map;
map += size;
}
return;
}

size = PAGE_ALIGN(size);
map = __alloc_bootmem_node_high(NODE_DATA(nodeid), size * map_count,
PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
if (map) {
for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
if (!present_section_nr(pnum))
continue;
map_map[pnum] = map;
map += size;
}
return;
}

/* fallback */
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;
}
}
#endif /* !CONFIG_SPARSEMEM_VMEMMAP */

#ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
static void __init sparse_early_mem_maps_alloc_node(struct page **map_map,
unsigned long pnum_begin,
unsigned long pnum_end,
unsigned long map_count, int nodeid)
{
sparse_mem_maps_populate_node(map_map, pnum_begin, pnum_end,
map_count, nodeid);
}
#else
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 = sparse_mem_map_populate(pnum, nid);
if (map)
return map;

printk(KERN_ERR "%s: sparsemem memory map backing failed "
"some memory will not be available.\n", __func__);
ms->section_mem_map = 0;
return NULL;
}
#endif

void __attribute__((weak)) __meminit vmemmap_populate_print_last(void)
{
}

/*
* 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;
unsigned long *usemap;
unsigned long **usemap_map;
int size;
int nodeid_begin = 0;
unsigned long pnum_begin = 0;
unsigned long usemap_count;
#ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
unsigned long map_count;
int size2;
struct page **map_map;
#endif

/*
* map is using big page (aka 2M in x86 64 bit)
* usemap is less one page (aka 24 bytes)
* so alloc 2M (with 2M align) and 24 bytes in turn will
* make next 2M slip to one more 2M later.
* then in big system, the memory will have a lot of holes...
* here try to allocate 2M pages continuously.
*
* powerpc need to call sparse_init_one_section right after each
* sparse_early_mem_map_alloc, so allocate usemap_map at first.
*/
size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
usemap_map = alloc_bootmem(size);
if (!usemap_map)
panic("can not allocate usemap_map\n");

for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
struct mem_section *ms;

if (!present_section_nr(pnum))
continue;
ms = __nr_to_section(pnum);
nodeid_begin = sparse_early_nid(ms);
pnum_begin = pnum;
break;
}
usemap_count = 1;
for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
struct mem_section *ms;
int nodeid;

if (!present_section_nr(pnum))
continue;
ms = __nr_to_section(pnum);
nodeid = sparse_early_nid(ms);
if (nodeid == nodeid_begin) {
usemap_count++;
continue;
}
/* ok, we need to take cake of from pnum_begin to pnum - 1*/
sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, pnum,
usemap_count, nodeid_begin);
/* new start, update count etc*/
nodeid_begin = nodeid;
pnum_begin = pnum;
usemap_count = 1;
}
/* ok, last chunk */
sparse_early_usemaps_alloc_node(usemap_map, pnum_begin, NR_MEM_SECTIONS,
usemap_count, nodeid_begin);

#ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
size2 = sizeof(struct page *) * NR_MEM_SECTIONS;
map_map = alloc_bootmem(size2);
if (!map_map)
panic("can not allocate map_map\n");

for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
struct mem_section *ms;

if (!present_section_nr(pnum))
continue;
ms = __nr_to_section(pnum);
nodeid_begin = sparse_early_nid(ms);
pnum_begin = pnum;
break;
}
map_count = 1;
for (pnum = pnum_begin + 1; pnum < NR_MEM_SECTIONS; pnum++) {
struct mem_section *ms;
int nodeid;

if (!present_section_nr(pnum))
continue;
ms = __nr_to_section(pnum);
nodeid = sparse_early_nid(ms);
if (nodeid == nodeid_begin) {
map_count++;
continue;
}
/* ok, we need to take cake of from pnum_begin to pnum - 1*/
sparse_early_mem_maps_alloc_node(map_map, pnum_begin, pnum,
map_count, nodeid_begin);
/* new start, update count etc*/
nodeid_begin = nodeid;
pnum_begin = pnum;
map_count = 1;
}
/* ok, last chunk */
sparse_early_mem_maps_alloc_node(map_map, pnum_begin, NR_MEM_SECTIONS,
map_count, nodeid_begin);
#endif

for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
if (!present_section_nr(pnum))
continue;

usemap = usemap_map[pnum];
if (!usemap)
continue;

#ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
map = map_map[pnum];
#else
map = sparse_early_mem_map_alloc(pnum);
#endif
if (!map)
continue;

sparse_init_one_section(__nr_to_section(pnum), pnum, map,
usemap);
}

vmemmap_populate_print_last();

#ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
free_bootmem(__pa(map_map), size2);
#endif
free_bootmem(__pa(usemap_map), size);
}

#ifdef CONFIG_MEMORY_HOTPLUG
#ifdef CONFIG_SPARSEMEM_VMEMMAP
static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
unsigned long nr_pages)
{
/* This will make the necessary allocations eventually. */
return sparse_mem_map_populate(pnum, nid);
}
static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
{
return; /* XXX: Not implemented yet */
}
static void free_map_bootmem(struct page *page, unsigned long nr_pages)
{
}
#else
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 inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
unsigned long nr_pages)
{
return __kmalloc_section_memmap(nr_pages);
}

static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
{
if (is_vmalloc_addr(memmap))
vfree(memmap);
else
free_pages((unsigned long)memmap,
get_order(sizeof(struct page) * nr_pages));
}

static void free_map_bootmem(struct page *page, unsigned long nr_pages)
{
unsigned long maps_section_nr, removing_section_nr, i;
unsigned long magic;

for (i = 0; i < nr_pages; i++, page++) {
magic = (unsigned long) page->lru.next;

BUG_ON(magic == NODE_INFO);

maps_section_nr = pfn_to_section_nr(page_to_pfn(page));
removing_section_nr = page->private;

/*
* When this function is called, the removing section is
* logical offlined state. This means all pages are isolated
* from page allocator. If removing section's memmap is placed
* on the same section, it must not be freed.
* If it is freed, page allocator may allocate it which will
* be removed physically soon.
*/
if (maps_section_nr != removing_section_nr)
put_page_bootmem(page);
}
}
#endif /* CONFIG_SPARSEMEM_VMEMMAP */

static void free_section_usemap(struct page *memmap, unsigned long *usemap)
{
struct page *usemap_page;
unsigned long nr_pages;

if (!usemap)
return;

usemap_page = virt_to_page(usemap);
/*
* Check to see if allocation came from hot-plug-add
*/
if (PageSlab(usemap_page)) {
kfree(usemap);
if (memmap)
__kfree_section_memmap(memmap, PAGES_PER_SECTION);
return;
}

/*
* The usemap came from bootmem. This is packed with other usemaps
* on the section which has pgdat at boot time. Just keep it as is now.
*/

if (memmap) {
struct page *memmap_page;
memmap_page = virt_to_page(memmap);

nr_pages = PAGE_ALIGN(PAGES_PER_SECTION * sizeof(struct page))
>> PAGE_SHIFT;

free_map_bootmem(memmap_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 __meminit 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 *usemap;
unsigned long flags;
int ret;

/*
* no locking for this, because it does its own
* plus, it does a kmalloc
*/
ret = sparse_index_init(section_nr, pgdat->node_id);
if (ret < 0 && ret != -EEXIST)
return ret;
memmap = kmalloc_section_memmap(section_nr, pgdat->node_id, nr_pages);
if (!memmap)
return -ENOMEM;
usemap = __kmalloc_section_usemap();
if (!usemap) {
__kfree_section_memmap(memmap, nr_pages);
return -ENOMEM;
}

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, usemap);

out:
pgdat_resize_unlock(pgdat, &flags);
if (ret <= 0) {
kfree(usemap);
__kfree_section_memmap(memmap, nr_pages);
}
return ret;
}

void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
{
struct page *memmap = NULL;
unsigned long *usemap = NULL;

if (ms->section_mem_map) {
usemap = ms->pageblock_flags;
memmap = sparse_decode_mem_map(ms->section_mem_map,
__section_nr(ms));
ms->section_mem_map = 0;
ms->pageblock_flags = NULL;
}

free_section_usemap(memmap, usemap);
}
#endif
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