e820.c

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/*
 * Handle the memory map.
 * The functions here do the job until bootmem takes over.
 *
 *  Getting sanitize_e820_map() in sync with i386 version by applying change:
 *  -  Provisions for empty E820 memory regions (reported by certain BIOSes).
 *     Alex Achenbach <[email protected]>, December 2002.
 *  Venkatesh Pallipadi <[email protected]>
 *
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/crash_dump.h>
#include <linux/export.h>
#include <linux/bootmem.h>
#include <linux/pfn.h>
#include <linux/suspend.h>
#include <linux/acpi.h>
#include <linux/firmware-map.h>
#include <linux/memblock.h>
#include <linux/sort.h>

#include <asm/e820.h>
#include <asm/proto.h>
#include <asm/setup.h>

/*
 * The e820 map is the map that gets modified e.g. with command line parameters
 * and that is also registered with modifications in the kernel resource tree
 * with the iomem_resource as parent.
 *
 * The e820_saved is directly saved after the BIOS-provided memory map is
 * copied. It doesn't get modified afterwards. It's registered for the
 * /sys/firmware/memmap interface.
 *
 * That memory map is not modified and is used as base for kexec. The kexec'd
 * kernel should get the same memory map as the firmware provides. Then the
 * user can e.g. boot the original kernel with mem=1G while still booting the
 * next kernel with full memory.
 */
struct e820map e820;
struct e820map e820_saved;

/* For PCI or other memory-mapped resources */
unsigned long pci_mem_start = 0xaeedbabe;
#ifdef CONFIG_PCI
EXPORT_SYMBOL(pci_mem_start);
#endif

/*
 * This function checks if any part of the range <start,end> is mapped
 * with type.
 */
int
e820_any_mapped(u64 start, u64 end, unsigned type)
{
    int i;

    for (i = 0; i < e820.nr_map; i++) {
        struct e820entry *ei = &e820.map[i];

        if (type && ei->type != type)
            continue;
        if (ei->addr >= end || ei->addr + ei->size <= start)
            continue;
        return 1;
    }
    return 0;
}
EXPORT_SYMBOL_GPL(e820_any_mapped);

/*
 * This function checks if the entire range <start,end> is mapped with type.
 *
 * Note: this function only works correct if the e820 table is sorted and
 * not-overlapping, which is the case
 */
int __init e820_all_mapped(u64 start, u64 end, unsigned type)
{
    int i;

    for (i = 0; i < e820.nr_map; i++) {
        struct e820entry *ei = &e820.map[i];

        if (type && ei->type != type)
            continue;
        /* is the region (part) in overlap with the current region ?*/
        if (ei->addr >= end || ei->addr + ei->size <= start)
            continue;

        /* if the region is at the beginning of <start,end> we move
         * start to the end of the region since it's ok until there
         */
        if (ei->addr <= start)
            start = ei->addr + ei->size;
        /*
         * if start is now at or beyond end, we're done, full
         * coverage
         */
        if (start >= end)
            return 1;
    }
    return 0;
}

/*
 * Add a memory region to the kernel e820 map.
 */
static void __init __e820_add_region(struct e820map *e820x, u64 start, u64 size,
                     int type)
{
    int x = e820x->nr_map;

    if (x >= ARRAY_SIZE(e820x->map)) {
        printk(KERN_ERR "e820: too many entries; ignoring [mem %#010llx-%#010llx]\n",
               (unsigned long long) start,
               (unsigned long long) (start + size - 1));
        return;
    }

    e820x->map[x].addr = start;
    e820x->map[x].size = size;
    e820x->map[x].type = type;
    e820x->nr_map++;
}

void __init e820_add_region(u64 start, u64 size, int type)
{
    __e820_add_region(&e820, start, size, type);
}

static void __init e820_print_type(u32 type)
{
    switch (type) {
    case E820_RAM:
    case E820_RESERVED_KERN:
        printk(KERN_CONT "usable");
        break;
    case E820_RESERVED:
        printk(KERN_CONT "reserved");
        break;
    case E820_ACPI:
        printk(KERN_CONT "ACPI data");
        break;
    case E820_NVS:
        printk(KERN_CONT "ACPI NVS");
        break;
    case E820_UNUSABLE:
        printk(KERN_CONT "unusable");
        break;
    default:
        printk(KERN_CONT "type %u", type);
        break;
    }
}

void __init e820_print_map(char *who)
{
    int i;

    for (i = 0; i < e820.nr_map; i++) {
        printk(KERN_INFO "%s: [mem %#018Lx-%#018Lx] ", who,
               (unsigned long long) e820.map[i].addr,
               (unsigned long long)
               (e820.map[i].addr + e820.map[i].size - 1));
        e820_print_type(e820.map[i].type);
        printk(KERN_CONT "\n");
    }
}

/*
 * Sanitize the BIOS e820 map.
 *
 * Some e820 responses include overlapping entries. The following
 * replaces the original e820 map with a new one, removing overlaps,
 * and resolving conflicting memory types in favor of highest
 * numbered type.
 *
 * The input parameter biosmap points to an array of 'struct
 * e820entry' which on entry has elements in the range [0, *pnr_map)
 * valid, and which has space for up to max_nr_map entries.
 * On return, the resulting sanitized e820 map entries will be in
 * overwritten in the same location, starting at biosmap.
 *
 * The integer pointed to by pnr_map must be valid on entry (the
 * current number of valid entries located at biosmap) and will
 * be updated on return, with the new number of valid entries
 * (something no more than max_nr_map.)
 *
 * The return value from sanitize_e820_map() is zero if it
 * successfully 'sanitized' the map entries passed in, and is -1
 * if it did nothing, which can happen if either of (1) it was
 * only passed one map entry, or (2) any of the input map entries
 * were invalid (start + size < start, meaning that the size was
 * so big the described memory range wrapped around through zero.)
 *
 *  Visually we're performing the following
 *  (1,2,3,4 = memory types)...
 *
 *  Sample memory map (w/overlaps):
 *     ____22__________________
 *     ______________________4_
 *     ____1111________________
 *     _44_____________________
 *     11111111________________
 *     ____________________33__
 *     ___________44___________
 *     __________33333_________
 *     ______________22________
 *     ___________________2222_
 *     _________111111111______
 *     _____________________11_
 *     _________________4______
 *
 *  Sanitized equivalent (no overlap):
 *     1_______________________
 *     _44_____________________
 *     ___1____________________
 *     ____22__________________
 *     ______11________________
 *     _________1______________
 *     __________3_____________
 *     ___________44___________
 *     _____________33_________
 *     _______________2________
 *     ________________1_______
 *     _________________4______
 *     ___________________2____
 *     ____________________33__
 *     ______________________4_
 */
struct change_member {
    struct e820entry *pbios; /* pointer to original bios entry */
    unsigned long long addr; /* address for this change point */
};

static int __init cpcompare(const void *a, const void *b)
{
    struct change_member * const *app = a, * const *bpp = b;
    const struct change_member *ap = *app, *bp = *bpp;

    /*
     * Inputs are pointers to two elements of change_point[].  If their
     * addresses are unequal, their difference dominates.  If the addresses
     * are equal, then consider one that represents the end of its region
     * to be greater than one that does not.
     */
    if (ap->addr != bp->addr)
        return ap->addr > bp->addr ? 1 : -1;

    return (ap->addr != ap->pbios->addr) - (bp->addr != bp->pbios->addr);
}

int __init sanitize_e820_map(struct e820entry *biosmap, int max_nr_map,
                 u32 *pnr_map)
{
    static struct change_member change_point_list[2*E820_X_MAX] __initdata;
    static struct change_member *change_point[2*E820_X_MAX] __initdata;
    static struct e820entry *overlap_list[E820_X_MAX] __initdata;
    static struct e820entry new_bios[E820_X_MAX] __initdata;
    unsigned long current_type, last_type;
    unsigned long long last_addr;
    int chgidx;
    int overlap_entries;
    int new_bios_entry;
    int old_nr, new_nr, chg_nr;
    int i;

    /* if there's only one memory region, don't bother */
    if (*pnr_map < 2)
        return -1;

    old_nr = *pnr_map;
    BUG_ON(old_nr > max_nr_map);

    /* bail out if we find any unreasonable addresses in bios map */
    for (i = 0; i < old_nr; i++)
        if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
            return -1;

    /* create pointers for initial change-point information (for sorting) */
    for (i = 0; i < 2 * old_nr; i++)
        change_point[i] = &change_point_list[i];

    /* record all known change-points (starting and ending addresses),
       omitting those that are for empty memory regions */
    chgidx = 0;
    for (i = 0; i < old_nr; i++)    {
        if (biosmap[i].size != 0) {
            change_point[chgidx]->addr = biosmap[i].addr;
            change_point[chgidx++]->pbios = &biosmap[i];
            change_point[chgidx]->addr = biosmap[i].addr +
                biosmap[i].size;
            change_point[chgidx++]->pbios = &biosmap[i];
        }
    }
    chg_nr = chgidx;

    /* sort change-point list by memory addresses (low -> high) */
    sort(change_point, chg_nr, sizeof *change_point, cpcompare, NULL);

    /* create a new bios memory map, removing overlaps */
    overlap_entries = 0;     /* number of entries in the overlap table */
    new_bios_entry = 0;  /* index for creating new bios map entries */
    last_type = 0;       /* start with undefined memory type */
    last_addr = 0;       /* start with 0 as last starting address */

    /* loop through change-points, determining affect on the new bios map */
    for (chgidx = 0; chgidx < chg_nr; chgidx++) {
        /* keep track of all overlapping bios entries */
        if (change_point[chgidx]->addr ==
            change_point[chgidx]->pbios->addr) {
            /*
             * add map entry to overlap list (> 1 entry
             * implies an overlap)
             */
            overlap_list[overlap_entries++] =
                change_point[chgidx]->pbios;
        } else {
            /*
             * remove entry from list (order independent,
             * so swap with last)
             */
            for (i = 0; i < overlap_entries; i++) {
                if (overlap_list[i] ==
                    change_point[chgidx]->pbios)
                    overlap_list[i] =
                        overlap_list[overlap_entries-1];
            }
            overlap_entries--;
        }
        /*
         * if there are overlapping entries, decide which
         * "type" to use (larger value takes precedence --
         * 1=usable, 2,3,4,4+=unusable)
         */
        current_type = 0;
        for (i = 0; i < overlap_entries; i++)
            if (overlap_list[i]->type > current_type)
                current_type = overlap_list[i]->type;
        /*
         * continue building up new bios map based on this
         * information
         */
        if (current_type != last_type)  {
            if (last_type != 0)  {
                new_bios[new_bios_entry].size =
                    change_point[chgidx]->addr - last_addr;
                /*
                 * move forward only if the new size
                 * was non-zero
                 */
                if (new_bios[new_bios_entry].size != 0)
                    /*
                     * no more space left for new
                     * bios entries ?
                     */
                    if (++new_bios_entry >= max_nr_map)
                        break;
            }
            if (current_type != 0)  {
                new_bios[new_bios_entry].addr =
                    change_point[chgidx]->addr;
                new_bios[new_bios_entry].type = current_type;
                last_addr = change_point[chgidx]->addr;
            }
            last_type = current_type;
        }
    }
    /* retain count for new bios entries */
    new_nr = new_bios_entry;

    /* copy new bios mapping into original location */
    memcpy(biosmap, new_bios, new_nr * sizeof(struct e820entry));
    *pnr_map = new_nr;

    return 0;
}

static int __init __append_e820_map(struct e820entry *biosmap, int nr_map)
{
    while (nr_map) {
        u64 start = biosmap->addr;
        u64 size = biosmap->size;
        u64 end = start + size;
        u32 type = biosmap->type;

        /* Overflow in 64 bits? Ignore the memory map. */
        if (start > end)
            return -1;

        e820_add_region(start, size, type);

        biosmap++;
        nr_map--;
    }
    return 0;
}

/*
 * Copy the BIOS e820 map into a safe place.
 *
 * Sanity-check it while we're at it..
 *
 * If we're lucky and live on a modern system, the setup code
 * will have given us a memory map that we can use to properly
 * set up memory.  If we aren't, we'll fake a memory map.
 */
static int __init append_e820_map(struct e820entry *biosmap, int nr_map)
{
    /* Only one memory region (or negative)? Ignore it */
    if (nr_map < 2)
        return -1;

    return __append_e820_map(biosmap, nr_map);
}

static u64 __init __e820_update_range(struct e820map *e820x, u64 start,
                    u64 size, unsigned old_type,
                    unsigned new_type)
{
    u64 end;
    unsigned int i;
    u64 real_updated_size = 0;

    BUG_ON(old_type == new_type);

    if (size > (ULLONG_MAX - start))
        size = ULLONG_MAX - start;

    end = start + size;
    printk(KERN_DEBUG "e820: update [mem %#010Lx-%#010Lx] ",
           (unsigned long long) start, (unsigned long long) (end - 1));
    e820_print_type(old_type);
    printk(KERN_CONT " ==> ");
    e820_print_type(new_type);
    printk(KERN_CONT "\n");

    for (i = 0; i < e820x->nr_map; i++) {
        struct e820entry *ei = &e820x->map[i];
        u64 final_start, final_end;
        u64 ei_end;

        if (ei->type != old_type)
            continue;

        ei_end = ei->addr + ei->size;
        /* totally covered by new range? */
        if (ei->addr >= start && ei_end <= end) {
            ei->type = new_type;
            real_updated_size += ei->size;
            continue;
        }

        /* new range is totally covered? */
        if (ei->addr < start && ei_end > end) {
            __e820_add_region(e820x, start, size, new_type);
            __e820_add_region(e820x, end, ei_end - end, ei->type);
            ei->size = start - ei->addr;
            real_updated_size += size;
            continue;
        }

        /* partially covered */
        final_start = max(start, ei->addr);
        final_end = min(end, ei_end);
        if (final_start >= final_end)
            continue;

        __e820_add_region(e820x, final_start, final_end - final_start,
                  new_type);

        real_updated_size += final_end - final_start;

        /*
         * left range could be head or tail, so need to update
         * size at first.
         */
        ei->size -= final_end - final_start;
        if (ei->addr < final_start)
            continue;
        ei->addr = final_end;
    }
    return real_updated_size;
}

u64 __init e820_update_range(u64 start, u64 size, unsigned old_type,
                 unsigned new_type)
{
    return __e820_update_range(&e820, start, size, old_type, new_type);
}

static u64 __init e820_update_range_saved(u64 start, u64 size,
                      unsigned old_type, unsigned new_type)
{
    return __e820_update_range(&e820_saved, start, size, old_type,
                     new_type);
}

/* make e820 not cover the range */
u64 __init e820_remove_range(u64 start, u64 size, unsigned old_type,
                 int checktype)
{
    int i;
    u64 end;
    u64 real_removed_size = 0;

    if (size > (ULLONG_MAX - start))
        size = ULLONG_MAX - start;

    end = start + size;
    printk(KERN_DEBUG "e820: remove [mem %#010Lx-%#010Lx] ",
           (unsigned long long) start, (unsigned long long) (end - 1));
    if (checktype)
        e820_print_type(old_type);
    printk(KERN_CONT "\n");

    for (i = 0; i < e820.nr_map; i++) {
        struct e820entry *ei = &e820.map[i];
        u64 final_start, final_end;
        u64 ei_end;

        if (checktype && ei->type != old_type)
            continue;

        ei_end = ei->addr + ei->size;
        /* totally covered? */
        if (ei->addr >= start && ei_end <= end) {
            real_removed_size += ei->size;
            memset(ei, 0, sizeof(struct e820entry));
            continue;
        }

        /* new range is totally covered? */
        if (ei->addr < start && ei_end > end) {
            e820_add_region(end, ei_end - end, ei->type);
            ei->size = start - ei->addr;
            real_removed_size += size;
            continue;
        }

        /* partially covered */
        final_start = max(start, ei->addr);
        final_end = min(end, ei_end);
        if (final_start >= final_end)
            continue;
        real_removed_size += final_end - final_start;

        /*
         * left range could be head or tail, so need to update
         * size at first.
         */
        ei->size -= final_end - final_start;
        if (ei->addr < final_start)
            continue;
        ei->addr = final_end;
    }
    return real_removed_size;
}

void __init update_e820(void)
{
    u32 nr_map;

    nr_map = e820.nr_map;
    if (sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &nr_map))
        return;
    e820.nr_map = nr_map;
    printk(KERN_INFO "e820: modified physical RAM map:\n");
    e820_print_map("modified");
}
static void __init update_e820_saved(void)
{
    u32 nr_map;

    nr_map = e820_saved.nr_map;
    if (sanitize_e820_map(e820_saved.map, ARRAY_SIZE(e820_saved.map), &nr_map))
        return;
    e820_saved.nr_map = nr_map;
}
#define MAX_GAP_END 0x100000000ull
/*
 * Search for a gap in the e820 memory space from start_addr to end_addr.
 */
__init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
        unsigned long start_addr, unsigned long long end_addr)
{
    unsigned long long last;
    int i = e820.nr_map;
    int found = 0;

    last = (end_addr && end_addr < MAX_GAP_END) ? end_addr : MAX_GAP_END;

    while (--i >= 0) {
        unsigned long long start = e820.map[i].addr;
        unsigned long long end = start + e820.map[i].size;

        if (end < start_addr)
            continue;

        /*
         * Since "last" is at most 4GB, we know we'll
         * fit in 32 bits if this condition is true
         */
        if (last > end) {
            unsigned long gap = last - end;

            if (gap >= *gapsize) {
                *gapsize = gap;
                *gapstart = end;
                found = 1;
            }
        }
        if (start < last)
            last = start;
    }
    return found;
}

/*
 * Search for the biggest gap in the low 32 bits of the e820
 * memory space.  We pass this space to PCI to assign MMIO resources
 * for hotplug or unconfigured devices in.
 * Hopefully the BIOS let enough space left.
 */
__init void e820_setup_gap(void)
{
    unsigned long gapstart, gapsize;
    int found;

    gapstart = 0x10000000;
    gapsize = 0x400000;
    found  = e820_search_gap(&gapstart, &gapsize, 0, MAX_GAP_END);

#ifdef CONFIG_X86_64
    if (!found) {
        gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
        printk(KERN_ERR
    "e820: cannot find a gap in the 32bit address range\n"
    "e820: PCI devices with unassigned 32bit BARs may break!\n");
    }
#endif

    /*
     * e820_reserve_resources_late protect stolen RAM already
     */
    pci_mem_start = gapstart;

    printk(KERN_INFO
           "e820: [mem %#010lx-%#010lx] available for PCI devices\n",
           gapstart, gapstart + gapsize - 1);
}

void __init parse_e820_ext(struct setup_data *sdata)
{
    int entries;
    struct e820entry *extmap;

    entries = sdata->len / sizeof(struct e820entry);
    extmap = (struct e820entry *)(sdata->data);
    __append_e820_map(extmap, entries);
    sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
    printk(KERN_INFO "e820: extended physical RAM map:\n");
    e820_print_map("extended");
}

#if defined(CONFIG_X86_64) || \
    (defined(CONFIG_X86_32) && defined(CONFIG_HIBERNATION))

void __init e820_mark_nosave_regions(unsigned long limit_pfn)
{
    int i;
    unsigned long pfn;

    pfn = PFN_DOWN(e820.map[0].addr + e820.map[0].size);
    for (i = 1; i < e820.nr_map; i++) {
        struct e820entry *ei = &e820.map[i];

        if (pfn < PFN_UP(ei->addr))
            register_nosave_region(pfn, PFN_UP(ei->addr));

        pfn = PFN_DOWN(ei->addr + ei->size);
        if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
            register_nosave_region(PFN_UP(ei->addr), pfn);

        if (pfn >= limit_pfn)
            break;
    }
}
#endif

#ifdef CONFIG_ACPI

static int __init e820_mark_nvs_memory(void)
{
    int i;

    for (i = 0; i < e820.nr_map; i++) {
        struct e820entry *ei = &e820.map[i];

        if (ei->type == E820_NVS)
            acpi_nvs_register(ei->addr, ei->size);
    }

    return 0;
}
core_initcall(e820_mark_nvs_memory);
#endif

/*
 * pre allocated 4k and reserved it in memblock and e820_saved
 */
u64 __init early_reserve_e820(u64 size, u64 align)
{
    u64 addr;

    addr = __memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
    if (addr) {
        e820_update_range_saved(addr, size, E820_RAM, E820_RESERVED);
        printk(KERN_INFO "e820: update e820_saved for early_reserve_e820\n");
        update_e820_saved();
    }

    return addr;
}

#ifdef CONFIG_X86_32
# ifdef CONFIG_X86_PAE
#  define MAX_ARCH_PFN      (1ULL<<(36-PAGE_SHIFT))
# else
#  define MAX_ARCH_PFN      (1ULL<<(32-PAGE_SHIFT))
# endif
#else /* CONFIG_X86_32 */
# define MAX_ARCH_PFN MAXMEM>>PAGE_SHIFT
#endif

/*
 * Find the highest page frame number we have available
 */
static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type)
{
    int i;
    unsigned long last_pfn = 0;
    unsigned long max_arch_pfn = MAX_ARCH_PFN;

    for (i = 0; i < e820.nr_map; i++) {
        struct e820entry *ei = &e820.map[i];
        unsigned long start_pfn;
        unsigned long end_pfn;

        if (ei->type != type)
            continue;

        start_pfn = ei->addr >> PAGE_SHIFT;
        end_pfn = (ei->addr + ei->size) >> PAGE_SHIFT;

        if (start_pfn >= limit_pfn)
            continue;
        if (end_pfn > limit_pfn) {
            last_pfn = limit_pfn;
            break;
        }
        if (end_pfn > last_pfn)
            last_pfn = end_pfn;
    }

    if (last_pfn > max_arch_pfn)
        last_pfn = max_arch_pfn;

    printk(KERN_INFO "e820: last_pfn = %#lx max_arch_pfn = %#lx\n",
             last_pfn, max_arch_pfn);
    return last_pfn;
}
unsigned long __init e820_end_of_ram_pfn(void)
{
    return e820_end_pfn(MAX_ARCH_PFN, E820_RAM);
}

unsigned long __init e820_end_of_low_ram_pfn(void)
{
    return e820_end_pfn(1UL<<(32 - PAGE_SHIFT), E820_RAM);
}

static void early_panic(char *msg)
{
    early_printk(msg);
    panic(msg);
}

static int userdef __initdata;

/* "mem=nopentium" disables the 4MB page tables. */
static int __init parse_memopt(char *p)
{
    u64 mem_size;

    if (!p)
        return -EINVAL;

    if (!strcmp(p, "nopentium")) {
#ifdef CONFIG_X86_32
        setup_clear_cpu_cap(X86_FEATURE_PSE);
        return 0;
#else
        printk(KERN_WARNING "mem=nopentium ignored! (only supported on x86_32)\n");
        return -EINVAL;
#endif
    }

    userdef = 1;
    mem_size = memparse(p, &p);
    /* don't remove all of memory when handling "mem={invalid}" param */
    if (mem_size == 0)
        return -EINVAL;
    e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);

    return 0;
}
early_param("mem", parse_memopt);

static int __init parse_memmap_opt(char *p)
{
    char *oldp;
    u64 start_at, mem_size;

    if (!p)
        return -EINVAL;

    if (!strncmp(p, "exactmap", 8)) {
#ifdef CONFIG_CRASH_DUMP
        /*
         * If we are doing a crash dump, we still need to know
         * the real mem size before original memory map is
         * reset.
         */
        saved_max_pfn = e820_end_of_ram_pfn();
#endif
        e820.nr_map = 0;
        userdef = 1;
        return 0;
    }

    oldp = p;
    mem_size = memparse(p, &p);
    if (p == oldp)
        return -EINVAL;

    userdef = 1;
    if (*p == '@') {
        start_at = memparse(p+1, &p);
        e820_add_region(start_at, mem_size, E820_RAM);
    } else if (*p == '#') {
        start_at = memparse(p+1, &p);
        e820_add_region(start_at, mem_size, E820_ACPI);
    } else if (*p == '$') {
        start_at = memparse(p+1, &p);
        e820_add_region(start_at, mem_size, E820_RESERVED);
    } else
        e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);

    return *p == '\0' ? 0 : -EINVAL;
}
early_param("memmap", parse_memmap_opt);

void __init finish_e820_parsing(void)
{
    if (userdef) {
        u32 nr = e820.nr_map;

        if (sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &nr) < 0)
            early_panic("Invalid user supplied memory map");
        e820.nr_map = nr;

        printk(KERN_INFO "e820: user-defined physical RAM map:\n");
        e820_print_map("user");
    }
}

static inline const char *e820_type_to_string(int e820_type)
{
    switch (e820_type) {
    case E820_RESERVED_KERN:
    case E820_RAM:  return "System RAM";
    case E820_ACPI: return "ACPI Tables";
    case E820_NVS:  return "ACPI Non-volatile Storage";
    case E820_UNUSABLE: return "Unusable memory";
    default:    return "reserved";
    }
}

/*
 * Mark e820 reserved areas as busy for the resource manager.
 */
static struct resource __initdata *e820_res;
void __init e820_reserve_resources(void)
{
    int i;
    struct resource *res;
    u64 end;

    res = alloc_bootmem(sizeof(struct resource) * e820.nr_map);
    e820_res = res;
    for (i = 0; i < e820.nr_map; i++) {
        end = e820.map[i].addr + e820.map[i].size - 1;
        if (end != (resource_size_t)end) {
            res++;
            continue;
        }
        res->name = e820_type_to_string(e820.map[i].type);
        res->start = e820.map[i].addr;
        res->end = end;

        res->flags = IORESOURCE_MEM;

        /*
         * don't register the region that could be conflicted with
         * pci device BAR resource and insert them later in
         * pcibios_resource_survey()
         */
        if (e820.map[i].type != E820_RESERVED || res->start < (1ULL<<20)) {
            res->flags |= IORESOURCE_BUSY;
            insert_resource(&iomem_resource, res);
        }
        res++;
    }

    for (i = 0; i < e820_saved.nr_map; i++) {
        struct e820entry *entry = &e820_saved.map[i];
        firmware_map_add_early(entry->addr,
            entry->addr + entry->size,
            e820_type_to_string(entry->type));
    }
}

/* How much should we pad RAM ending depending on where it is? */
static unsigned long ram_alignment(resource_size_t pos)
{
    unsigned long mb = pos >> 20;

    /* To 64kB in the first megabyte */
    if (!mb)
        return 64*1024;

    /* To 1MB in the first 16MB */
    if (mb < 16)
        return 1024*1024;

    /* To 64MB for anything above that */
    return 64*1024*1024;
}

#define MAX_RESOURCE_SIZE ((resource_size_t)-1)

void __init e820_reserve_resources_late(void)
{
    int i;
    struct resource *res;

    res = e820_res;
    for (i = 0; i < e820.nr_map; i++) {
        if (!res->parent && res->end)
            insert_resource_expand_to_fit(&iomem_resource, res);
        res++;
    }

    /*
     * Try to bump up RAM regions to reasonable boundaries to
     * avoid stolen RAM:
     */
    for (i = 0; i < e820.nr_map; i++) {
        struct e820entry *entry = &e820.map[i];
        u64 start, end;

        if (entry->type != E820_RAM)
            continue;
        start = entry->addr + entry->size;
        end = round_up(start, ram_alignment(start)) - 1;
        if (end > MAX_RESOURCE_SIZE)
            end = MAX_RESOURCE_SIZE;
        if (start >= end)
            continue;
        printk(KERN_DEBUG
               "e820: reserve RAM buffer [mem %#010llx-%#010llx]\n",
               start, end);
        reserve_region_with_split(&iomem_resource, start, end,
                      "RAM buffer");
    }
}

char *__init default_machine_specific_memory_setup(void)
{
    char *who = "BIOS-e820";
    u32 new_nr;
    /*
     * Try to copy the BIOS-supplied E820-map.
     *
     * Otherwise fake a memory map; one section from 0k->640k,
     * the next section from 1mb->appropriate_mem_k
     */
    new_nr = boot_params.e820_entries;
    sanitize_e820_map(boot_params.e820_map,
            ARRAY_SIZE(boot_params.e820_map),
            &new_nr);
    boot_params.e820_entries = new_nr;
    if (append_e820_map(boot_params.e820_map, boot_params.e820_entries)
      < 0) {
        u64 mem_size;

        /* compare results from other methods and take the greater */
        if (boot_params.alt_mem_k
            < boot_params.screen_info.ext_mem_k) {
            mem_size = boot_params.screen_info.ext_mem_k;
            who = "BIOS-88";
        } else {
            mem_size = boot_params.alt_mem_k;
            who = "BIOS-e801";
        }

        e820.nr_map = 0;
        e820_add_region(0, LOWMEMSIZE(), E820_RAM);
        e820_add_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
    }

    /* In case someone cares... */
    return who;
}

void __init setup_memory_map(void)
{
    char *who;

    who = x86_init.resources.memory_setup();
    memcpy(&e820_saved, &e820, sizeof(struct e820map));
    printk(KERN_INFO "e820: BIOS-provided physical RAM map:\n");
    e820_print_map(who);
}

void __init memblock_x86_fill(void)
{
    int i;
    u64 end;

    /*
     * EFI may have more than 128 entries
     * We are safe to enable resizing, beause memblock_x86_fill()
     * is rather later for x86
     */
    memblock_allow_resize();

    for (i = 0; i < e820.nr_map; i++) {
        struct e820entry *ei = &e820.map[i];

        end = ei->addr + ei->size;
        if (end != (resource_size_t)end)
            continue;

        if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
            continue;

        memblock_add(ei->addr, ei->size);
    }

    /* throw away partial pages */
    memblock_trim_memory(PAGE_SIZE);

    memblock_dump_all();
}

void __init memblock_find_dma_reserve(void)
{
#ifdef CONFIG_X86_64
    u64 nr_pages = 0, nr_free_pages = 0;
    unsigned long start_pfn, end_pfn;
    phys_addr_t start, end;
    int i;
    u64 u;

    /*
     * need to find out used area below MAX_DMA_PFN
     * need to use memblock to get free size in [0, MAX_DMA_PFN]
     * at first, and assume boot_mem will not take below MAX_DMA_PFN
     */
    for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
        start_pfn = min_t(unsigned long, start_pfn, MAX_DMA_PFN);
        end_pfn = min_t(unsigned long, end_pfn, MAX_DMA_PFN);
        nr_pages += end_pfn - start_pfn;
    }

    for_each_free_mem_range(u, MAX_NUMNODES, &start, &end, NULL) {
        start_pfn = min_t(unsigned long, PFN_UP(start), MAX_DMA_PFN);
        end_pfn = min_t(unsigned long, PFN_DOWN(end), MAX_DMA_PFN);
        if (start_pfn < end_pfn)
            nr_free_pages += end_pfn - start_pfn;
    }

    set_dma_reserve(nr_pages - nr_free_pages);
#endif
}