#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/ioport.h>
#include <linux/string.h>
#include <linux/kexec.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/efi.h>
#include <linux/pfn.h>
#include <linux/uaccess.h>

#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/e820.h>
#include <asm/setup.h>

#ifdef CONFIG_EFI
int efi_enabled = 0;
EXPORT_SYMBOL(efi_enabled);
#endif

struct e820map e820;
struct change_member {
        struct e820entry *pbios; /* pointer to original bios entry */
        unsigned long long addr; /* address for this change point */
};
static struct change_member change_point_list[2*E820MAX] __initdata;
static struct change_member *change_point[2*E820MAX] __initdata;
static struct e820entry *overlap_list[E820MAX] __initdata;
static struct e820entry new_bios[E820MAX] __initdata;
/* For PCI or other memory-mapped resources */
unsigned long pci_mem_start = 0x10000000;
#ifdef CONFIG_PCI
EXPORT_SYMBOL(pci_mem_start);
#endif
extern int user_defined_memmap;
struct resource data_resource = {
        .name   = "Kernel data",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_BUSY | IORESOURCE_MEM
};

struct resource code_resource = {
        .name   = "Kernel code",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_BUSY | IORESOURCE_MEM
};

static struct resource system_rom_resource = {
        .name   = "System ROM",
        .start  = 0xf0000,
        .end    = 0xfffff,
        .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
};

static struct resource extension_rom_resource = {
        .name   = "Extension ROM",
        .start  = 0xe0000,
        .end    = 0xeffff,
        .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
};

static struct resource adapter_rom_resources[] = { {
        .name   = "Adapter ROM",
        .start  = 0xc8000,
        .end    = 0,
        .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
        .name   = "Adapter ROM",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
        .name   = "Adapter ROM",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
        .name   = "Adapter ROM",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
        .name   = "Adapter ROM",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
}, {
        .name   = "Adapter ROM",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
} };

static struct resource video_rom_resource = {
        .name   = "Video ROM",
        .start  = 0xc0000,
        .end    = 0xc7fff,
        .flags  = IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
};

static struct resource video_ram_resource = {
        .name   = "Video RAM area",
        .start  = 0xa0000,
        .end    = 0xbffff,
        .flags  = IORESOURCE_BUSY | IORESOURCE_MEM
};

static struct resource standard_io_resources[] = { {
        .name   = "dma1",
        .start  = 0x0000,
        .end    = 0x001f,
        .flags  = IORESOURCE_BUSY | IORESOURCE_IO
}, {
        .name   = "pic1",
        .start  = 0x0020,
        .end    = 0x0021,
        .flags  = IORESOURCE_BUSY | IORESOURCE_IO
}, {
        .name   = "timer0",
        .start  = 0x0040,
        .end    = 0x0043,
        .flags  = IORESOURCE_BUSY | IORESOURCE_IO
}, {
        .name   = "timer1",
        .start  = 0x0050,
        .end    = 0x0053,
        .flags  = IORESOURCE_BUSY | IORESOURCE_IO
}, {
        .name   = "keyboard",
        .start  = 0x0060,
        .end    = 0x006f,
        .flags  = IORESOURCE_BUSY | IORESOURCE_IO
}, {
        .name   = "dma page reg",
        .start  = 0x0080,
        .end    = 0x008f,
        .flags  = IORESOURCE_BUSY | IORESOURCE_IO
}, {
        .name   = "pic2",
        .start  = 0x00a0,
        .end    = 0x00a1,
        .flags  = IORESOURCE_BUSY | IORESOURCE_IO
}, {
        .name   = "dma2",
        .start  = 0x00c0,
        .end    = 0x00df,
        .flags  = IORESOURCE_BUSY | IORESOURCE_IO
}, {
        .name   = "fpu",
        .start  = 0x00f0,
        .end    = 0x00ff,
        .flags  = IORESOURCE_BUSY | IORESOURCE_IO
} };

#define ROMSIGNATURE 0xaa55

static int __init romsignature(const unsigned char *rom)
{
        const unsigned short * const ptr = (const unsigned short *)rom;
        unsigned short sig;

        return probe_kernel_address(ptr, sig) == 0 && sig == ROMSIGNATURE;
}

static int __init romchecksum(const unsigned char *rom, unsigned long length)
{
        unsigned char sum, c;

        for (sum = 0; length && probe_kernel_address(rom++, c) == 0; length--)
                sum += c;
        return !length && !sum;
}

static void __init probe_roms(void)
{
        const unsigned char *rom;
        unsigned long start, length, upper;
        unsigned char c;
        int i;

        /* video rom */
        upper = adapter_rom_resources[0].start;
        for (start = video_rom_resource.start; start < upper; start += 2048) {
                rom = isa_bus_to_virt(start);
                if (!romsignature(rom))
                        continue;

                video_rom_resource.start = start;

                if (probe_kernel_address(rom + 2, c) != 0)
                        continue;

                /* 0 < length <= 0x7f * 512, historically */
                length = c * 512;

                /* if checksum okay, trust length byte */
                if (length && romchecksum(rom, length))
                        video_rom_resource.end = start + length - 1;

                request_resource(&iomem_resource, &video_rom_resource);
                break;
        }

        start = (video_rom_resource.end + 1 + 2047) & ~2047UL;
        if (start < upper)
                start = upper;

        /* system rom */
        request_resource(&iomem_resource, &system_rom_resource);
        upper = system_rom_resource.start;

        /* check for extension rom (ignore length byte!) */
        rom = isa_bus_to_virt(extension_rom_resource.start);
        if (romsignature(rom)) {
                length = extension_rom_resource.end - extension_rom_resource.start + 1;
                if (romchecksum(rom, length)) {
                        request_resource(&iomem_resource, &extension_rom_resource);
                        upper = extension_rom_resource.start;
                }
        }

        /* check for adapter roms on 2k boundaries */
        for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += 2048) {
                rom = isa_bus_to_virt(start);
                if (!romsignature(rom))
                        continue;

                if (probe_kernel_address(rom + 2, c) != 0)
                        continue;

                /* 0 < length <= 0x7f * 512, historically */
                length = c * 512;

                /* but accept any length that fits if checksum okay */
                if (!length || start + length > upper || !romchecksum(rom, length))
                        continue;

                adapter_rom_resources[i].start = start;
                adapter_rom_resources[i].end = start + length - 1;
                request_resource(&iomem_resource, &adapter_rom_resources[i]);

                start = adapter_rom_resources[i++].end & ~2047UL;
        }
}

/*
 * Request address space for all standard RAM and ROM resources
 * and also for regions reported as reserved by the e820.
 */
static void __init
legacy_init_iomem_resources(struct resource *code_resource, struct resource *data_resource)
{
        int i;

        probe_roms();
        for (i = 0; i < e820.nr_map; i++) {
                struct resource *res;
#ifndef CONFIG_RESOURCES_64BIT
                if (e820.map[i].addr + e820.map[i].size > 0x100000000ULL)
                        continue;
#endif
                res = kzalloc(sizeof(struct resource), GFP_ATOMIC);
                switch (e820.map[i].type) {
                case E820_RAM:  res->name = "System RAM"; break;
                case E820_ACPI: res->name = "ACPI Tables"; break;
                case E820_NVS:  res->name = "ACPI Non-volatile Storage"; break;
                default:        res->name = "reserved";
                }
                res->start = e820.map[i].addr;
                res->end = res->start + e820.map[i].size - 1;
                res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
                if (request_resource(&iomem_resource, res)) {
                        kfree(res);
                        continue;
                }
                if (e820.map[i].type == E820_RAM) {
                        /*
                         *  We don't know which RAM region contains kernel data,
                         *  so we try it repeatedly and let the resource manager
                         *  test it.
                         */
                        request_resource(res, code_resource);
                        request_resource(res, data_resource);
#ifdef CONFIG_KEXEC
                        request_resource(res, &crashk_res);
#endif
                }
        }
}

/*
 * Request address space for all standard resources
 *
 * This is called just before pcibios_init(), which is also a
 * subsys_initcall, but is linked in later (in arch/i386/pci/common.c).
 */
static int __init request_standard_resources(void)
{
        int i;

        printk("Setting up standard PCI resources\n");
        if (efi_enabled)
                efi_initialize_iomem_resources(&code_resource, &data_resource);
        else
                legacy_init_iomem_resources(&code_resource, &data_resource);

        /* EFI systems may still have VGA */
        request_resource(&iomem_resource, &video_ram_resource);

        /* request I/O space for devices used on all i[345]86 PCs */
        for (i = 0; i < ARRAY_SIZE(standard_io_resources); i++)
                request_resource(&ioport_resource, &standard_io_resources[i]);
        return 0;
}

subsys_initcall(request_standard_resources);

void __init add_memory_region(unsigned long long start,
                              unsigned long long size, int type)
{
        int x;

        if (!efi_enabled) {
                x = e820.nr_map;

                if (x == E820MAX) {
                    printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
                    return;
                }

                e820.map[x].addr = start;
                e820.map[x].size = size;
                e820.map[x].type = type;
                e820.nr_map++;
        }
} /* add_memory_region */

/*
 * Sanitize the BIOS e820 map.
 *
 * Some e820 responses include overlapping entries.  The following
 * replaces the original e820 map with a new one, removing overlaps.
 *
 */
int __init sanitize_e820_map(struct e820entry * biosmap, char * pnr_map)
{
        struct change_member *change_tmp;
        unsigned long current_type, last_type;
        unsigned long long last_addr;
        int chgidx, still_changing;
        int overlap_entries;
        int new_bios_entry;
        int old_nr, new_nr, chg_nr;
        int i;

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

        old_nr = *pnr_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;        /* true number of change-points */

        /* sort change-point list by memory addresses (low -> high) */
        still_changing = 1;
        while (still_changing)  {
                still_changing = 0;
                for (i=1; i < chg_nr; i++)  {
                        /* if <current_addr> > <last_addr>, swap */
                        /* or, if current=<start_addr> & last=<end_addr>, swap */
                        if ((change_point[i]->addr < change_point[i-1]->addr) ||
                                ((change_point[i]->addr == change_point[i-1]->addr) &&
                                 (change_point[i]->addr == change_point[i]->pbios->addr) &&
                                 (change_point[i-1]->addr != change_point[i-1]->pbios->addr))
                           )
                        {
                                change_tmp = change_point[i];
                                change_point[i] = change_point[i-1];
                                change_point[i-1] = change_tmp;
                                still_changing=1;
                        }
                }
        }

        /* 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)
                                        if (++new_bios_entry >= E820MAX)
                                                break;  /* no more space left for new bios entries */
                        }
                        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;
                }
        }
        new_nr = new_bios_entry;   /* retain count for new bios entries */

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

        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.
 *
 * We check to see that the memory map contains at least 2 elements
 * before we'll use it, because the detection code in setup.S may
 * not be perfect and most every PC known to man has two memory
 * regions: one from 0 to 640k, and one from 1mb up.  (The IBM
 * thinkpad 560x, for example, does not cooperate with the memory
 * detection code.)
 */
int __init copy_e820_map(struct e820entry * biosmap, int nr_map)
{
        /* Only one memory region (or negative)? Ignore it */
        if (nr_map < 2)
                return -1;

        do {
                unsigned long long start = biosmap->addr;
                unsigned long long size = biosmap->size;
                unsigned long long end = start + size;
                unsigned long type = biosmap->type;

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

                /*
                 * Some BIOSes claim RAM in the 640k - 1M region.
                 * Not right. Fix it up.
                 */
                if (type == E820_RAM) {
                        if (start < 0x100000ULL && end > 0xA0000ULL) {
                                if (start < 0xA0000ULL)
                                        add_memory_region(start, 0xA0000ULL-start, type);
                                if (end <= 0x100000ULL)
                                        continue;
                                start = 0x100000ULL;
                                size = end - start;
                        }
                }
                add_memory_region(start, size, type);
        } while (biosmap++,--nr_map);
        return 0;
}

/*
 * Callback for efi_memory_walk.
 */
static int __init
efi_find_max_pfn(unsigned long start, unsigned long end, void *arg)
{
        unsigned long *max_pfn = arg, pfn;

        if (start < end) {
                pfn = PFN_UP(end -1);
                if (pfn > *max_pfn)
                        *max_pfn = pfn;
        }
        return 0;
}

static int __init
efi_memory_present_wrapper(unsigned long start, unsigned long end, void *arg)
{
        memory_present(0, PFN_UP(start), PFN_DOWN(end));
        return 0;
}

/*
 * Find the highest page frame number we have available
 */
void __init find_max_pfn(void)
{
        int i;

        max_pfn = 0;
        if (efi_enabled) {
                efi_memmap_walk(efi_find_max_pfn, &max_pfn);
                efi_memmap_walk(efi_memory_present_wrapper, NULL);
                return;
        }

        for (i = 0; i < e820.nr_map; i++) {
                unsigned long start, end;
                /* RAM? */
                if (e820.map[i].type != E820_RAM)
                        continue;
                start = PFN_UP(e820.map[i].addr);
                end = PFN_DOWN(e820.map[i].addr + e820.map[i].size);
                if (start >= end)
                        continue;
                if (end > max_pfn)
                        max_pfn = end;
                memory_present(0, start, end);
        }
}

/*
 * Free all available memory for boot time allocation.  Used
 * as a callback function by efi_memory_walk()
 */

static int __init
free_available_memory(unsigned long start, unsigned long end, void *arg)
{
        /* check max_low_pfn */
        if (start >= (max_low_pfn << PAGE_SHIFT))
                return 0;
        if (end >= (max_low_pfn << PAGE_SHIFT))
                end = max_low_pfn << PAGE_SHIFT;
        if (start < end)
                free_bootmem(start, end - start);

        return 0;
}
/*
 * Register fully available low RAM pages with the bootmem allocator.
 */
void __init register_bootmem_low_pages(unsigned long max_low_pfn)
{
        int i;

        if (efi_enabled) {
                efi_memmap_walk(free_available_memory, NULL);
                return;
        }
        for (i = 0; i < e820.nr_map; i++) {
                unsigned long curr_pfn, last_pfn, size;
                /*
                 * Reserve usable low memory
                 */
                if (e820.map[i].type != E820_RAM)
                        continue;
                /*
                 * We are rounding up the start address of usable memory:
                 */
                curr_pfn = PFN_UP(e820.map[i].addr);
                if (curr_pfn >= max_low_pfn)
                        continue;
                /*
                 * ... and at the end of the usable range downwards:
                 */
                last_pfn = PFN_DOWN(e820.map[i].addr + e820.map[i].size);

                if (last_pfn > max_low_pfn)
                        last_pfn = max_low_pfn;

                /*
                 * .. finally, did all the rounding and playing
                 * around just make the area go away?
                 */
                if (last_pfn <= curr_pfn)
                        continue;

                size = last_pfn - curr_pfn;
                free_bootmem(PFN_PHYS(curr_pfn), PFN_PHYS(size));
        }
}

void __init e820_register_memory(void)
{
        unsigned long gapstart, gapsize, round;
        unsigned long long last;
        int i;

        /*
         * Search for the bigest gap in the low 32 bits of the e820
         * memory space.
         */
        last = 0x100000000ull;
        gapstart = 0x10000000;
        gapsize = 0x400000;
        i = e820.nr_map;
        while (--i >= 0) {
                unsigned long long start = e820.map[i].addr;
                unsigned long long end = start + e820.map[i].size;

                /*
                 * 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;
                        }
                }
                if (start < last)
                        last = start;
        }

        /*
         * See how much we want to round up: start off with
         * rounding to the next 1MB area.
         */
        round = 0x100000;
        while ((gapsize >> 4) > round)
                round += round;
        /* Fun with two's complement */
        pci_mem_start = (gapstart + round) & -round;

        printk("Allocating PCI resources starting at %08lx (gap: %08lx:%08lx)\n",
                pci_mem_start, gapstart, gapsize);
}

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

        for (i = 0; i < e820.nr_map; i++) {
                printk(" %s: %016Lx - %016Lx ", who,
                        e820.map[i].addr,
                        e820.map[i].addr + e820.map[i].size);
                switch (e820.map[i].type) {
                case E820_RAM:  printk("(usable)\n");
                                break;
                case E820_RESERVED:
                                printk("(reserved)\n");
                                break;
                case E820_ACPI:
                                printk("(ACPI data)\n");
                                break;
                case E820_NVS:
                                printk("(ACPI NVS)\n");
                                break;
                default:        printk("type %lu\n", e820.map[i].type);
                                break;
                }
        }
}

static __init __always_inline void efi_limit_regions(unsigned long long size)
{
        unsigned long long current_addr = 0;
        efi_memory_desc_t *md, *next_md;
        void *p, *p1;
        int i, j;

        j = 0;
        p1 = memmap.map;
        for (p = p1, i = 0; p < memmap.map_end; p += memmap.desc_size, i++) {
                md = p;
                next_md = p1;
                current_addr = md->phys_addr +
                        PFN_PHYS(md->num_pages);
                if (is_available_memory(md)) {
                        if (md->phys_addr >= size) continue;
                        memcpy(next_md, md, memmap.desc_size);
                        if (current_addr >= size) {
                                next_md->num_pages -=
                                        PFN_UP(current_addr-size);
                        }
                        p1 += memmap.desc_size;
                        next_md = p1;
                        j++;
                } else if ((md->attribute & EFI_MEMORY_RUNTIME) ==
                           EFI_MEMORY_RUNTIME) {
                        /* In order to make runtime services
                         * available we have to include runtime
                         * memory regions in memory map */
                        memcpy(next_md, md, memmap.desc_size);
                        p1 += memmap.desc_size;
                        next_md = p1;
                        j++;
                }
        }
        memmap.nr_map = j;
        memmap.map_end = memmap.map +
                (memmap.nr_map * memmap.desc_size);
}

void __init limit_regions(unsigned long long size)
{
        unsigned long long current_addr;
        int i;

        print_memory_map("limit_regions start");
        if (efi_enabled) {
                efi_limit_regions(size);
                return;
        }
        for (i = 0; i < e820.nr_map; i++) {
                current_addr = e820.map[i].addr + e820.map[i].size;
                if (current_addr < size)
                        continue;

                if (e820.map[i].type != E820_RAM)
                        continue;

                if (e820.map[i].addr >= size) {
                        /*
                         * This region starts past the end of the
                         * requested size, skip it completely.
                         */
                        e820.nr_map = i;
                } else {
                        e820.nr_map = i + 1;
                        e820.map[i].size -= current_addr - size;
                }
                print_memory_map("limit_regions endfor");
                return;
        }
        print_memory_map("limit_regions endfunc");
}

/*
 * 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++) {
                const 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(unsigned long s, unsigned long e, unsigned type)
{
        u64 start = s;
        u64 end = e;
        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; /* we're done */
        }
        return 0;
}

static int __init parse_memmap(char *arg)
{
        if (!arg)
                return -EINVAL;

        if (strcmp(arg, "exactmap") == 0) {
#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.
                 */
                find_max_pfn();
                saved_max_pfn = max_pfn;
#endif
                e820.nr_map = 0;
                user_defined_memmap = 1;
        } else {
                /* If the user specifies memory size, we
                 * limit the BIOS-provided memory map to
                 * that size. exactmap can be used to specify
                 * the exact map. mem=number can be used to
                 * trim the existing memory map.
                 */
                unsigned long long start_at, mem_size;

                mem_size = memparse(arg, &arg);
                if (*arg == '@') {
                        start_at = memparse(arg+1, &arg);
                        add_memory_region(start_at, mem_size, E820_RAM);
                } else if (*arg == '#') {
                        start_at = memparse(arg+1, &arg);
                        add_memory_region(start_at, mem_size, E820_ACPI);
                } else if (*arg == '$') {
                        start_at = memparse(arg+1, &arg);
                        add_memory_region(start_at, mem_size, E820_RESERVED);
                } else {
                        limit_regions(mem_size);
                        user_defined_memmap = 1;
                }
        }
        return 0;
}
early_param("memmap", parse_memmap);