Merge tag 'gpio-v3.13-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw...

[linux-2.6.git] / mm / memblock.c

/*
 * Procedures for maintaining information about logical memory blocks.
 *
 * Peter Bergner, IBM Corp.     June 2001.
 * Copyright (C) 2001 Peter Bergner.
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/poison.h>
#include <linux/pfn.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/memblock.h>

#include <asm-generic/sections.h>

static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock;
static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock;

struct memblock memblock __initdata_memblock = {
        .memory.regions         = memblock_memory_init_regions,
        .memory.cnt             = 1,    /* empty dummy entry */
        .memory.max             = INIT_MEMBLOCK_REGIONS,

        .reserved.regions       = memblock_reserved_init_regions,
        .reserved.cnt           = 1,    /* empty dummy entry */
        .reserved.max           = INIT_MEMBLOCK_REGIONS,

        .bottom_up              = false,
        .current_limit          = MEMBLOCK_ALLOC_ANYWHERE,
};

int memblock_debug __initdata_memblock;
static int memblock_can_resize __initdata_memblock;
static int memblock_memory_in_slab __initdata_memblock = 0;
static int memblock_reserved_in_slab __initdata_memblock = 0;

/* inline so we don't get a warning when pr_debug is compiled out */
static __init_memblock const char *
memblock_type_name(struct memblock_type *type)
{
        if (type == &memblock.memory)
                return "memory";
        else if (type == &memblock.reserved)
                return "reserved";
        else
                return "unknown";
}

/* adjust *@size so that (@base + *@size) doesn't overflow, return new size */
static inline phys_addr_t memblock_cap_size(phys_addr_t base, phys_addr_t *size)
{
        return *size = min(*size, (phys_addr_t)ULLONG_MAX - base);
}

/*
 * Address comparison utilities
 */
static unsigned long __init_memblock memblock_addrs_overlap(phys_addr_t base1, phys_addr_t size1,
                                       phys_addr_t base2, phys_addr_t size2)
{
        return ((base1 < (base2 + size2)) && (base2 < (base1 + size1)));
}

static long __init_memblock memblock_overlaps_region(struct memblock_type *type,
                                        phys_addr_t base, phys_addr_t size)
{
        unsigned long i;

        for (i = 0; i < type->cnt; i++) {
                phys_addr_t rgnbase = type->regions[i].base;
                phys_addr_t rgnsize = type->regions[i].size;
                if (memblock_addrs_overlap(base, size, rgnbase, rgnsize))
                        break;
        }

        return (i < type->cnt) ? i : -1;
}

/*
 * __memblock_find_range_bottom_up - find free area utility in bottom-up
 * @start: start of candidate range
 * @end: end of candidate range, can be %MEMBLOCK_ALLOC_{ANYWHERE|ACCESSIBLE}
 * @size: size of free area to find
 * @align: alignment of free area to find
 * @nid: nid of the free area to find, %MAX_NUMNODES for any node
 *
 * Utility called from memblock_find_in_range_node(), find free area bottom-up.
 *
 * RETURNS:
 * Found address on success, 0 on failure.
 */
static phys_addr_t __init_memblock
__memblock_find_range_bottom_up(phys_addr_t start, phys_addr_t end,
                                phys_addr_t size, phys_addr_t align, int nid)
{
        phys_addr_t this_start, this_end, cand;
        u64 i;

        for_each_free_mem_range(i, nid, &this_start, &this_end, NULL) {
                this_start = clamp(this_start, start, end);
                this_end = clamp(this_end, start, end);

                cand = round_up(this_start, align);
                if (cand < this_end && this_end - cand >= size)
                        return cand;
        }

        return 0;
}

/**
 * __memblock_find_range_top_down - find free area utility, in top-down
 * @start: start of candidate range
 * @end: end of candidate range, can be %MEMBLOCK_ALLOC_{ANYWHERE|ACCESSIBLE}
 * @size: size of free area to find
 * @align: alignment of free area to find
 * @nid: nid of the free area to find, %MAX_NUMNODES for any node
 *
 * Utility called from memblock_find_in_range_node(), find free area top-down.
 *
 * RETURNS:
 * Found address on success, 0 on failure.
 */
static phys_addr_t __init_memblock
__memblock_find_range_top_down(phys_addr_t start, phys_addr_t end,
                               phys_addr_t size, phys_addr_t align, int nid)
{
        phys_addr_t this_start, this_end, cand;
        u64 i;

        for_each_free_mem_range_reverse(i, nid, &this_start, &this_end, NULL) {
                this_start = clamp(this_start, start, end);
                this_end = clamp(this_end, start, end);

                if (this_end < size)
                        continue;

                cand = round_down(this_end - size, align);
                if (cand >= this_start)
                        return cand;
        }

        return 0;
}

/**
 * memblock_find_in_range_node - find free area in given range and node
 * @start: start of candidate range
 * @end: end of candidate range, can be %MEMBLOCK_ALLOC_{ANYWHERE|ACCESSIBLE}
 * @size: size of free area to find
 * @align: alignment of free area to find
 * @nid: nid of the free area to find, %MAX_NUMNODES for any node
 *
 * Find @size free area aligned to @align in the specified range and node.
 *
 * When allocation direction is bottom-up, the @start should be greater
 * than the end of the kernel image. Otherwise, it will be trimmed. The
 * reason is that we want the bottom-up allocation just near the kernel
 * image so it is highly likely that the allocated memory and the kernel
 * will reside in the same node.
 *
 * If bottom-up allocation failed, will try to allocate memory top-down.
 *
 * RETURNS:
 * Found address on success, 0 on failure.
 */
phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t start,
                                        phys_addr_t end, phys_addr_t size,
                                        phys_addr_t align, int nid)
{
        int ret;
        phys_addr_t kernel_end;

        /* pump up @end */
        if (end == MEMBLOCK_ALLOC_ACCESSIBLE)
                end = memblock.current_limit;

        /* avoid allocating the first page */
        start = max_t(phys_addr_t, start, PAGE_SIZE);
        end = max(start, end);
        kernel_end = __pa_symbol(_end);

        /*
         * try bottom-up allocation only when bottom-up mode
         * is set and @end is above the kernel image.
         */
        if (memblock_bottom_up() && end > kernel_end) {
                phys_addr_t bottom_up_start;

                /* make sure we will allocate above the kernel */
                bottom_up_start = max(start, kernel_end);

                /* ok, try bottom-up allocation first */
                ret = __memblock_find_range_bottom_up(bottom_up_start, end,
                                                      size, align, nid);
                if (ret)
                        return ret;

                /*
                 * we always limit bottom-up allocation above the kernel,
                 * but top-down allocation doesn't have the limit, so
                 * retrying top-down allocation may succeed when bottom-up
                 * allocation failed.
                 *
                 * bottom-up allocation is expected to be fail very rarely,
                 * so we use WARN_ONCE() here to see the stack trace if
                 * fail happens.
                 */
                WARN_ONCE(1, "memblock: bottom-up allocation failed, "
                             "memory hotunplug may be affected\n");
        }

        return __memblock_find_range_top_down(start, end, size, align, nid);
}

/**
 * memblock_find_in_range - find free area in given range
 * @start: start of candidate range
 * @end: end of candidate range, can be %MEMBLOCK_ALLOC_{ANYWHERE|ACCESSIBLE}
 * @size: size of free area to find
 * @align: alignment of free area to find
 *
 * Find @size free area aligned to @align in the specified range.
 *
 * RETURNS:
 * Found address on success, 0 on failure.
 */
phys_addr_t __init_memblock memblock_find_in_range(phys_addr_t start,
                                        phys_addr_t end, phys_addr_t size,
                                        phys_addr_t align)
{
        return memblock_find_in_range_node(start, end, size, align,
                                           MAX_NUMNODES);
}

static void __init_memblock memblock_remove_region(struct memblock_type *type, unsigned long r)
{
        type->total_size -= type->regions[r].size;
        memmove(&type->regions[r], &type->regions[r + 1],
                (type->cnt - (r + 1)) * sizeof(type->regions[r]));
        type->cnt--;

        /* Special case for empty arrays */
        if (type->cnt == 0) {
                WARN_ON(type->total_size != 0);
                type->cnt = 1;
                type->regions[0].base = 0;
                type->regions[0].size = 0;
                memblock_set_region_node(&type->regions[0], MAX_NUMNODES);
        }
}

phys_addr_t __init_memblock get_allocated_memblock_reserved_regions_info(
                                        phys_addr_t *addr)
{
        if (memblock.reserved.regions == memblock_reserved_init_regions)
                return 0;

        *addr = __pa(memblock.reserved.regions);

        return PAGE_ALIGN(sizeof(struct memblock_region) *
                          memblock.reserved.max);
}

/**
 * memblock_double_array - double the size of the memblock regions array
 * @type: memblock type of the regions array being doubled
 * @new_area_start: starting address of memory range to avoid overlap with
 * @new_area_size: size of memory range to avoid overlap with
 *
 * Double the size of the @type regions array. If memblock is being used to
 * allocate memory for a new reserved regions array and there is a previously
 * allocated memory range [@new_area_start,@new_area_start+@new_area_size]
 * waiting to be reserved, ensure the memory used by the new array does
 * not overlap.
 *
 * RETURNS:
 * 0 on success, -1 on failure.
 */
static int __init_memblock memblock_double_array(struct memblock_type *type,
                                                phys_addr_t new_area_start,
                                                phys_addr_t new_area_size)
{
        struct memblock_region *new_array, *old_array;
        phys_addr_t old_alloc_size, new_alloc_size;
        phys_addr_t old_size, new_size, addr;
        int use_slab = slab_is_available();
        int *in_slab;

        /* We don't allow resizing until we know about the reserved regions
         * of memory that aren't suitable for allocation
         */
        if (!memblock_can_resize)
                return -1;

        /* Calculate new doubled size */
        old_size = type->max * sizeof(struct memblock_region);
        new_size = old_size << 1;
        /*
         * We need to allocated new one align to PAGE_SIZE,
         *   so we can free them completely later.
         */
        old_alloc_size = PAGE_ALIGN(old_size);
        new_alloc_size = PAGE_ALIGN(new_size);

        /* Retrieve the slab flag */
        if (type == &memblock.memory)
                in_slab = &memblock_memory_in_slab;
        else
                in_slab = &memblock_reserved_in_slab;

        /* Try to find some space for it.
         *
         * WARNING: We assume that either slab_is_available() and we use it or
         * we use MEMBLOCK for allocations. That means that this is unsafe to
         * use when bootmem is currently active (unless bootmem itself is
         * implemented on top of MEMBLOCK which isn't the case yet)
         *
         * This should however not be an issue for now, as we currently only
         * call into MEMBLOCK while it's still active, or much later when slab
         * is active for memory hotplug operations
         */
        if (use_slab) {
                new_array = kmalloc(new_size, GFP_KERNEL);
                addr = new_array ? __pa(new_array) : 0;
        } else {
                /* only exclude range when trying to double reserved.regions */
                if (type != &memblock.reserved)
                        new_area_start = new_area_size = 0;

                addr = memblock_find_in_range(new_area_start + new_area_size,
                                                memblock.current_limit,
                                                new_alloc_size, PAGE_SIZE);
                if (!addr && new_area_size)
                        addr = memblock_find_in_range(0,
                                min(new_area_start, memblock.current_limit),
                                new_alloc_size, PAGE_SIZE);

                new_array = addr ? __va(addr) : NULL;
        }
        if (!addr) {
                pr_err("memblock: Failed to double %s array from %ld to %ld entries !\n",
                       memblock_type_name(type), type->max, type->max * 2);
                return -1;
        }

        memblock_dbg("memblock: %s is doubled to %ld at [%#010llx-%#010llx]",
                        memblock_type_name(type), type->max * 2, (u64)addr,
                        (u64)addr + new_size - 1);

        /*
         * Found space, we now need to move the array over before we add the
         * reserved region since it may be our reserved array itself that is
         * full.
         */
        memcpy(new_array, type->regions, old_size);
        memset(new_array + type->max, 0, old_size);
        old_array = type->regions;
        type->regions = new_array;
        type->max <<= 1;

        /* Free old array. We needn't free it if the array is the static one */
        if (*in_slab)
                kfree(old_array);
        else if (old_array != memblock_memory_init_regions &&
                 old_array != memblock_reserved_init_regions)
                memblock_free(__pa(old_array), old_alloc_size);

        /*
         * Reserve the new array if that comes from the memblock.  Otherwise, we
         * needn't do it
         */
        if (!use_slab)
                BUG_ON(memblock_reserve(addr, new_alloc_size));

        /* Update slab flag */
        *in_slab = use_slab;

        return 0;
}

/**
 * memblock_merge_regions - merge neighboring compatible regions
 * @type: memblock type to scan
 *
 * Scan @type and merge neighboring compatible regions.
 */
static void __init_memblock memblock_merge_regions(struct memblock_type *type)
{
        int i = 0;

        /* cnt never goes below 1 */
        while (i < type->cnt - 1) {
                struct memblock_region *this = &type->regions[i];
                struct memblock_region *next = &type->regions[i + 1];

                if (this->base + this->size != next->base ||
                    memblock_get_region_node(this) !=
                    memblock_get_region_node(next)) {
                        BUG_ON(this->base + this->size > next->base);
                        i++;
                        continue;
                }

                this->size += next->size;
                /* move forward from next + 1, index of which is i + 2 */
                memmove(next, next + 1, (type->cnt - (i + 2)) * sizeof(*next));
                type->cnt--;
        }
}

/**
 * memblock_insert_region - insert new memblock region
 * @type:       memblock type to insert into
 * @idx:        index for the insertion point
 * @base:       base address of the new region
 * @size:       size of the new region
 * @nid:        node id of the new region
 *
 * Insert new memblock region [@base,@base+@size) into @type at @idx.
 * @type must already have extra room to accomodate the new region.
 */
static void __init_memblock memblock_insert_region(struct memblock_type *type,
                                                   int idx, phys_addr_t base,
                                                   phys_addr_t size, int nid)
{
        struct memblock_region *rgn = &type->regions[idx];

        BUG_ON(type->cnt >= type->max);
        memmove(rgn + 1, rgn, (type->cnt - idx) * sizeof(*rgn));
        rgn->base = base;
        rgn->size = size;
        memblock_set_region_node(rgn, nid);
        type->cnt++;
        type->total_size += size;
}

/**
 * memblock_add_region - add new memblock region
 * @type: memblock type to add new region into
 * @base: base address of the new region
 * @size: size of the new region
 * @nid: nid of the new region
 *
 * Add new memblock region [@base,@base+@size) into @type.  The new region
 * is allowed to overlap with existing ones - overlaps don't affect already
 * existing regions.  @type is guaranteed to be minimal (all neighbouring
 * compatible regions are merged) after the addition.
 *
 * RETURNS:
 * 0 on success, -errno on failure.
 */
static int __init_memblock memblock_add_region(struct memblock_type *type,
                                phys_addr_t base, phys_addr_t size, int nid)
{
        bool insert = false;
        phys_addr_t obase = base;
        phys_addr_t end = base + memblock_cap_size(base, &size);
        int i, nr_new;

        if (!size)
                return 0;

        /* special case for empty array */
        if (type->regions[0].size == 0) {
                WARN_ON(type->cnt != 1 || type->total_size);
                type->regions[0].base = base;
                type->regions[0].size = size;
                memblock_set_region_node(&type->regions[0], nid);
                type->total_size = size;
                return 0;
        }
repeat:
        /*
         * The following is executed twice.  Once with %false @insert and
         * then with %true.  The first counts the number of regions needed
         * to accomodate the new area.  The second actually inserts them.
         */
        base = obase;
        nr_new = 0;

        for (i = 0; i < type->cnt; i++) {
                struct memblock_region *rgn = &type->regions[i];
                phys_addr_t rbase = rgn->base;
                phys_addr_t rend = rbase + rgn->size;

                if (rbase >= end)
                        break;
                if (rend <= base)
                        continue;
                /*
                 * @rgn overlaps.  If it separates the lower part of new
                 * area, insert that portion.
                 */
                if (rbase > base) {
                        nr_new++;
                        if (insert)
                                memblock_insert_region(type, i++, base,
                                                       rbase - base, nid);
                }
                /* area below @rend is dealt with, forget about it */
                base = min(rend, end);
        }

        /* insert the remaining portion */
        if (base < end) {
                nr_new++;
                if (insert)
                        memblock_insert_region(type, i, base, end - base, nid);
        }

        /*
         * If this was the first round, resize array and repeat for actual
         * insertions; otherwise, merge and return.
         */
        if (!insert) {
                while (type->cnt + nr_new > type->max)
                        if (memblock_double_array(type, obase, size) < 0)
                                return -ENOMEM;
                insert = true;
                goto repeat;
        } else {
                memblock_merge_regions(type);
                return 0;
        }
}

int __init_memblock memblock_add_node(phys_addr_t base, phys_addr_t size,
                                       int nid)
{
        return memblock_add_region(&memblock.memory, base, size, nid);
}

int __init_memblock memblock_add(phys_addr_t base, phys_addr_t size)
{
        return memblock_add_region(&memblock.memory, base, size, MAX_NUMNODES);
}

/**
 * memblock_isolate_range - isolate given range into disjoint memblocks
 * @type: memblock type to isolate range for
 * @base: base of range to isolate
 * @size: size of range to isolate
 * @start_rgn: out parameter for the start of isolated region
 * @end_rgn: out parameter for the end of isolated region
 *
 * Walk @type and ensure that regions don't cross the boundaries defined by
 * [@base,@base+@size).  Crossing regions are split at the boundaries,
 * which may create at most two more regions.  The index of the first
 * region inside the range is returned in *@start_rgn and end in *@end_rgn.
 *
 * RETURNS:
 * 0 on success, -errno on failure.
 */
static int __init_memblock memblock_isolate_range(struct memblock_type *type,
                                        phys_addr_t base, phys_addr_t size,
                                        int *start_rgn, int *end_rgn)
{
        phys_addr_t end = base + memblock_cap_size(base, &size);
        int i;

        *start_rgn = *end_rgn = 0;

        if (!size)
                return 0;

        /* we'll create at most two more regions */
        while (type->cnt + 2 > type->max)
                if (memblock_double_array(type, base, size) < 0)
                        return -ENOMEM;

        for (i = 0; i < type->cnt; i++) {
                struct memblock_region *rgn = &type->regions[i];
                phys_addr_t rbase = rgn->base;
                phys_addr_t rend = rbase + rgn->size;

                if (rbase >= end)
                        break;
                if (rend <= base)
                        continue;

                if (rbase < base) {
                        /*
                         * @rgn intersects from below.  Split and continue
                         * to process the next region - the new top half.
                         */
                        rgn->base = base;
                        rgn->size -= base - rbase;
                        type->total_size -= base - rbase;
                        memblock_insert_region(type, i, rbase, base - rbase,
                                               memblock_get_region_node(rgn));
                } else if (rend > end) {
                        /*
                         * @rgn intersects from above.  Split and redo the
                         * current region - the new bottom half.
                         */
                        rgn->base = end;
                        rgn->size -= end - rbase;
                        type->total_size -= end - rbase;
                        memblock_insert_region(type, i--, rbase, end - rbase,
                                               memblock_get_region_node(rgn));
                } else {
                        /* @rgn is fully contained, record it */
                        if (!*end_rgn)
                                *start_rgn = i;
                        *end_rgn = i + 1;
                }
        }

        return 0;
}

static int __init_memblock __memblock_remove(struct memblock_type *type,
                                             phys_addr_t base, phys_addr_t size)
{
        int start_rgn, end_rgn;
        int i, ret;

        ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
        if (ret)
                return ret;

        for (i = end_rgn - 1; i >= start_rgn; i--)
                memblock_remove_region(type, i);
        return 0;
}

int __init_memblock memblock_remove(phys_addr_t base, phys_addr_t size)
{
        return __memblock_remove(&memblock.memory, base, size);
}

int __init_memblock memblock_free(phys_addr_t base, phys_addr_t size)
{
        memblock_dbg("   memblock_free: [%#016llx-%#016llx] %pF\n",
                     (unsigned long long)base,
                     (unsigned long long)base + size,
                     (void *)_RET_IP_);

        return __memblock_remove(&memblock.reserved, base, size);
}

int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
{
        struct memblock_type *_rgn = &memblock.reserved;

        memblock_dbg("memblock_reserve: [%#016llx-%#016llx] %pF\n",
                     (unsigned long long)base,
                     (unsigned long long)base + size,
                     (void *)_RET_IP_);

        return memblock_add_region(_rgn, base, size, MAX_NUMNODES);
}

/**
 * __next_free_mem_range - next function for for_each_free_mem_range()
 * @idx: pointer to u64 loop variable
 * @nid: node selector, %MAX_NUMNODES for all nodes
 * @out_start: ptr to phys_addr_t for start address of the range, can be %NULL
 * @out_end: ptr to phys_addr_t for end address of the range, can be %NULL
 * @out_nid: ptr to int for nid of the range, can be %NULL
 *
 * Find the first free area from *@idx which matches @nid, fill the out
 * parameters, and update *@idx for the next iteration.  The lower 32bit of
 * *@idx contains index into memory region and the upper 32bit indexes the
 * areas before each reserved region.  For example, if reserved regions
 * look like the following,
 *
 *      0:[0-16), 1:[32-48), 2:[128-130)
 *
 * The upper 32bit indexes the following regions.
 *
 *      0:[0-0), 1:[16-32), 2:[48-128), 3:[130-MAX)
 *
 * As both region arrays are sorted, the function advances the two indices
 * in lockstep and returns each intersection.
 */
void __init_memblock __next_free_mem_range(u64 *idx, int nid,
                                           phys_addr_t *out_start,
                                           phys_addr_t *out_end, int *out_nid)
{
        struct memblock_type *mem = &memblock.memory;
        struct memblock_type *rsv = &memblock.reserved;
        int mi = *idx & 0xffffffff;
        int ri = *idx >> 32;

        for ( ; mi < mem->cnt; mi++) {
                struct memblock_region *m = &mem->regions[mi];
                phys_addr_t m_start = m->base;
                phys_addr_t m_end = m->base + m->size;

                /* only memory regions are associated with nodes, check it */
                if (nid != MAX_NUMNODES && nid != memblock_get_region_node(m))
                        continue;

                /* scan areas before each reservation for intersection */
                for ( ; ri < rsv->cnt + 1; ri++) {
                        struct memblock_region *r = &rsv->regions[ri];
                        phys_addr_t r_start = ri ? r[-1].base + r[-1].size : 0;
                        phys_addr_t r_end = ri < rsv->cnt ? r->base : ULLONG_MAX;

                        /* if ri advanced past mi, break out to advance mi */
                        if (r_start >= m_end)
                                break;
                        /* if the two regions intersect, we're done */
                        if (m_start < r_end) {
                                if (out_start)
                                        *out_start = max(m_start, r_start);
                                if (out_end)
                                        *out_end = min(m_end, r_end);
                                if (out_nid)
                                        *out_nid = memblock_get_region_node(m);
                                /*
                                 * The region which ends first is advanced
                                 * for the next iteration.
                                 */
                                if (m_end <= r_end)
                                        mi++;
                                else
                                        ri++;
                                *idx = (u32)mi | (u64)ri << 32;
                                return;
                        }
                }
        }

        /* signal end of iteration */
        *idx = ULLONG_MAX;
}

/**
 * __next_free_mem_range_rev - next function for for_each_free_mem_range_reverse()
 * @idx: pointer to u64 loop variable
 * @nid: nid: node selector, %MAX_NUMNODES for all nodes
 * @out_start: ptr to phys_addr_t for start address of the range, can be %NULL
 * @out_end: ptr to phys_addr_t for end address of the range, can be %NULL
 * @out_nid: ptr to int for nid of the range, can be %NULL
 *
 * Reverse of __next_free_mem_range().
 */
void __init_memblock __next_free_mem_range_rev(u64 *idx, int nid,
                                           phys_addr_t *out_start,
                                           phys_addr_t *out_end, int *out_nid)
{
        struct memblock_type *mem = &memblock.memory;
        struct memblock_type *rsv = &memblock.reserved;
        int mi = *idx & 0xffffffff;
        int ri = *idx >> 32;

        if (*idx == (u64)ULLONG_MAX) {
                mi = mem->cnt - 1;
                ri = rsv->cnt;
        }

        for ( ; mi >= 0; mi--) {
                struct memblock_region *m = &mem->regions[mi];
                phys_addr_t m_start = m->base;
                phys_addr_t m_end = m->base + m->size;

                /* only memory regions are associated with nodes, check it */
                if (nid != MAX_NUMNODES && nid != memblock_get_region_node(m))
                        continue;

                /* scan areas before each reservation for intersection */
                for ( ; ri >= 0; ri--) {
                        struct memblock_region *r = &rsv->regions[ri];
                        phys_addr_t r_start = ri ? r[-1].base + r[-1].size : 0;
                        phys_addr_t r_end = ri < rsv->cnt ? r->base : ULLONG_MAX;

                        /* if ri advanced past mi, break out to advance mi */
                        if (r_end <= m_start)
                                break;
                        /* if the two regions intersect, we're done */
                        if (m_end > r_start) {
                                if (out_start)
                                        *out_start = max(m_start, r_start);
                                if (out_end)
                                        *out_end = min(m_end, r_end);
                                if (out_nid)
                                        *out_nid = memblock_get_region_node(m);

                                if (m_start >= r_start)
                                        mi--;
                                else
                                        ri--;
                                *idx = (u32)mi | (u64)ri << 32;
                                return;
                        }
                }
        }

        *idx = ULLONG_MAX;
}

#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
/*
 * Common iterator interface used to define for_each_mem_range().
 */
void __init_memblock __next_mem_pfn_range(int *idx, int nid,
                                unsigned long *out_start_pfn,
                                unsigned long *out_end_pfn, int *out_nid)
{
        struct memblock_type *type = &memblock.memory;
        struct memblock_region *r;

        while (++*idx < type->cnt) {
                r = &type->regions[*idx];

                if (PFN_UP(r->base) >= PFN_DOWN(r->base + r->size))
                        continue;
                if (nid == MAX_NUMNODES || nid == r->nid)
                        break;
        }
        if (*idx >= type->cnt) {
                *idx = -1;
                return;
        }

        if (out_start_pfn)
                *out_start_pfn = PFN_UP(r->base);
        if (out_end_pfn)
                *out_end_pfn = PFN_DOWN(r->base + r->size);
        if (out_nid)
                *out_nid = r->nid;
}

/**
 * memblock_set_node - set node ID on memblock regions
 * @base: base of area to set node ID for
 * @size: size of area to set node ID for
 * @nid: node ID to set
 *
 * Set the nid of memblock memory regions in [@base,@base+@size) to @nid.
 * Regions which cross the area boundaries are split as necessary.
 *
 * RETURNS:
 * 0 on success, -errno on failure.
 */
int __init_memblock memblock_set_node(phys_addr_t base, phys_addr_t size,
                                      int nid)
{
        struct memblock_type *type = &memblock.memory;
        int start_rgn, end_rgn;
        int i, ret;

        ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
        if (ret)
                return ret;

        for (i = start_rgn; i < end_rgn; i++)
                memblock_set_region_node(&type->regions[i], nid);

        memblock_merge_regions(type);
        return 0;
}
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */

static phys_addr_t __init memblock_alloc_base_nid(phys_addr_t size,
                                        phys_addr_t align, phys_addr_t max_addr,
                                        int nid)
{
        phys_addr_t found;

        if (WARN_ON(!align))
                align = __alignof__(long long);

        /* align @size to avoid excessive fragmentation on reserved array */
        size = round_up(size, align);

        found = memblock_find_in_range_node(0, max_addr, size, align, nid);
        if (found && !memblock_reserve(found, size))
                return found;

        return 0;
}

phys_addr_t __init memblock_alloc_nid(phys_addr_t size, phys_addr_t align, int nid)
{
        return memblock_alloc_base_nid(size, align, MEMBLOCK_ALLOC_ACCESSIBLE, nid);
}

phys_addr_t __init __memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
{
        return memblock_alloc_base_nid(size, align, max_addr, MAX_NUMNODES);
}

phys_addr_t __init memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
{
        phys_addr_t alloc;

        alloc = __memblock_alloc_base(size, align, max_addr);

        if (alloc == 0)
                panic("ERROR: Failed to allocate 0x%llx bytes below 0x%llx.\n",
                      (unsigned long long) size, (unsigned long long) max_addr);

        return alloc;
}

phys_addr_t __init memblock_alloc(phys_addr_t size, phys_addr_t align)
{
        return memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
}

phys_addr_t __init memblock_alloc_try_nid(phys_addr_t size, phys_addr_t align, int nid)
{
        phys_addr_t res = memblock_alloc_nid(size, align, nid);

        if (res)
                return res;
        return memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
}


/*
 * Remaining API functions
 */

phys_addr_t __init memblock_phys_mem_size(void)
{
        return memblock.memory.total_size;
}

phys_addr_t __init memblock_mem_size(unsigned long limit_pfn)
{
        unsigned long pages = 0;
        struct memblock_region *r;
        unsigned long start_pfn, end_pfn;

        for_each_memblock(memory, r) {
                start_pfn = memblock_region_memory_base_pfn(r);
                end_pfn = memblock_region_memory_end_pfn(r);
                start_pfn = min_t(unsigned long, start_pfn, limit_pfn);
                end_pfn = min_t(unsigned long, end_pfn, limit_pfn);
                pages += end_pfn - start_pfn;
        }

        return (phys_addr_t)pages << PAGE_SHIFT;
}

/* lowest address */
phys_addr_t __init_memblock memblock_start_of_DRAM(void)
{
        return memblock.memory.regions[0].base;
}

phys_addr_t __init_memblock memblock_end_of_DRAM(void)
{
        int idx = memblock.memory.cnt - 1;

        return (memblock.memory.regions[idx].base + memblock.memory.regions[idx].size);
}

void __init memblock_enforce_memory_limit(phys_addr_t limit)
{
        unsigned long i;
        phys_addr_t max_addr = (phys_addr_t)ULLONG_MAX;

        if (!limit)
                return;

        /* find out max address */
        for (i = 0; i < memblock.memory.cnt; i++) {
                struct memblock_region *r = &memblock.memory.regions[i];

                if (limit <= r->size) {
                        max_addr = r->base + limit;
                        break;
                }
                limit -= r->size;
        }

        /* truncate both memory and reserved regions */
        __memblock_remove(&memblock.memory, max_addr, (phys_addr_t)ULLONG_MAX);
        __memblock_remove(&memblock.reserved, max_addr, (phys_addr_t)ULLONG_MAX);
}

static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr)
{
        unsigned int left = 0, right = type->cnt;

        do {
                unsigned int mid = (right + left) / 2;

                if (addr < type->regions[mid].base)
                        right = mid;
                else if (addr >= (type->regions[mid].base +
                                  type->regions[mid].size))
                        left = mid + 1;
                else
                        return mid;
        } while (left < right);
        return -1;
}

int __init memblock_is_reserved(phys_addr_t addr)
{
        return memblock_search(&memblock.reserved, addr) != -1;
}

int __init_memblock memblock_is_memory(phys_addr_t addr)
{
        return memblock_search(&memblock.memory, addr) != -1;
}

#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
int __init_memblock memblock_search_pfn_nid(unsigned long pfn,
                         unsigned long *start_pfn, unsigned long *end_pfn)
{
        struct memblock_type *type = &memblock.memory;
        int mid = memblock_search(type, (phys_addr_t)pfn << PAGE_SHIFT);

        if (mid == -1)
                return -1;

        *start_pfn = type->regions[mid].base >> PAGE_SHIFT;
        *end_pfn = (type->regions[mid].base + type->regions[mid].size)
                        >> PAGE_SHIFT;

        return type->regions[mid].nid;
}
#endif

/**
 * memblock_is_region_memory - check if a region is a subset of memory
 * @base: base of region to check
 * @size: size of region to check
 *
 * Check if the region [@base, @base+@size) is a subset of a memory block.
 *
 * RETURNS:
 * 0 if false, non-zero if true
 */
int __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size)
{
        int idx = memblock_search(&memblock.memory, base);
        phys_addr_t end = base + memblock_cap_size(base, &size);

        if (idx == -1)
                return 0;
        return memblock.memory.regions[idx].base <= base &&
                (memblock.memory.regions[idx].base +
                 memblock.memory.regions[idx].size) >= end;
}

/**
 * memblock_is_region_reserved - check if a region intersects reserved memory
 * @base: base of region to check
 * @size: size of region to check
 *
 * Check if the region [@base, @base+@size) intersects a reserved memory block.
 *
 * RETURNS:
 * 0 if false, non-zero if true
 */
int __init_memblock memblock_is_region_reserved(phys_addr_t base, phys_addr_t size)
{
        memblock_cap_size(base, &size);
        return memblock_overlaps_region(&memblock.reserved, base, size) >= 0;
}

void __init_memblock memblock_trim_memory(phys_addr_t align)
{
        int i;
        phys_addr_t start, end, orig_start, orig_end;
        struct memblock_type *mem = &memblock.memory;

        for (i = 0; i < mem->cnt; i++) {
                orig_start = mem->regions[i].base;
                orig_end = mem->regions[i].base + mem->regions[i].size;
                start = round_up(orig_start, align);
                end = round_down(orig_end, align);

                if (start == orig_start && end == orig_end)
                        continue;

                if (start < end) {
                        mem->regions[i].base = start;
                        mem->regions[i].size = end - start;
                } else {
                        memblock_remove_region(mem, i);
                        i--;
                }
        }
}

void __init_memblock memblock_set_current_limit(phys_addr_t limit)
{
        memblock.current_limit = limit;
}

static void __init_memblock memblock_dump(struct memblock_type *type, char *name)
{
        unsigned long long base, size;
        int i;

        pr_info(" %s.cnt  = 0x%lx\n", name, type->cnt);

        for (i = 0; i < type->cnt; i++) {
                struct memblock_region *rgn = &type->regions[i];
                char nid_buf[32] = "";

                base = rgn->base;
                size = rgn->size;
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
                if (memblock_get_region_node(rgn) != MAX_NUMNODES)
                        snprintf(nid_buf, sizeof(nid_buf), " on node %d",
                                 memblock_get_region_node(rgn));
#endif
                pr_info(" %s[%#x]\t[%#016llx-%#016llx], %#llx bytes%s\n",
                        name, i, base, base + size - 1, size, nid_buf);
        }
}

void __init_memblock __memblock_dump_all(void)
{
        pr_info("MEMBLOCK configuration:\n");
        pr_info(" memory size = %#llx reserved size = %#llx\n",
                (unsigned long long)memblock.memory.total_size,
                (unsigned long long)memblock.reserved.total_size);

        memblock_dump(&memblock.memory, "memory");
        memblock_dump(&memblock.reserved, "reserved");
}

void __init memblock_allow_resize(void)
{
        memblock_can_resize = 1;
}

static int __init early_memblock(char *p)
{
        if (p && strstr(p, "debug"))
                memblock_debug = 1;
        return 0;
}
early_param("memblock", early_memblock);

#if defined(CONFIG_DEBUG_FS) && !defined(CONFIG_ARCH_DISCARD_MEMBLOCK)

static int memblock_debug_show(struct seq_file *m, void *private)
{
        struct memblock_type *type = m->private;
        struct memblock_region *reg;
        int i;

        for (i = 0; i < type->cnt; i++) {
                reg = &type->regions[i];
                seq_printf(m, "%4d: ", i);
                if (sizeof(phys_addr_t) == 4)
                        seq_printf(m, "0x%08lx..0x%08lx\n",
                                   (unsigned long)reg->base,
                                   (unsigned long)(reg->base + reg->size - 1));
                else
                        seq_printf(m, "0x%016llx..0x%016llx\n",
                                   (unsigned long long)reg->base,
                                   (unsigned long long)(reg->base + reg->size - 1));

        }
        return 0;
}

static int memblock_debug_open(struct inode *inode, struct file *file)
{
        return single_open(file, memblock_debug_show, inode->i_private);
}

static const struct file_operations memblock_debug_fops = {
        .open = memblock_debug_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
};

static int __init memblock_init_debugfs(void)
{
        struct dentry *root = debugfs_create_dir("memblock", NULL);
        if (!root)
                return -ENXIO;
        debugfs_create_file("memory", S_IRUGO, root, &memblock.memory, &memblock_debug_fops);
        debugfs_create_file("reserved", S_IRUGO, root, &memblock.reserved, &memblock_debug_fops);

        return 0;
}
__initcall(memblock_init_debugfs);

#endif /* CONFIG_DEBUG_FS */