text: /*
   * 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 <xela@slit.de>, December 2002.
   *  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   *
   */
  #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/pfn.h>
  #include <linux/suspend.h>
  #include <linux/firmware-map.h>
  
  #include <asm/pgtable.h>
  #include <asm/page.h>
  #include <asm/e820.h>
  #include <asm/proto.h>
  #include <asm/setup.h>
  #include <asm/trampoline.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 "Ooops! Too many entries in the memory map!\n");
  		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: %016Lx - %016Lx ", who,
  		       (unsigned long long) e820.map[i].addr,
  		       (unsigned long long)
  		       (e820.map[i].addr + e820.map[i].size));
  		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_
   */
  
  int __init sanitize_e820_map(struct e820entry *biosmap, int max_nr_map,
  			     u32 *pnr_map)
  {
  	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*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;
  	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;
  
  	/* 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) */
  	still_changing = 1;
  	while (still_changing)	{
  		still_changing = 0;
  		for (i = 1; i < chg_nr; i++)  {
  			unsigned long long curaddr, lastaddr;
  			unsigned long long curpbaddr, lastpbaddr;
  
  			curaddr = change_point[i]->addr;
  			lastaddr = change_point[i - 1]->addr;
  			curpbaddr = change_point[i]->pbios->addr;
  			lastpbaddr = change_point[i - 1]->pbios->addr;
  
  			/*
  			 * swap entries, when:
  			 *
  			 * curaddr > lastaddr or
  			 * curaddr == lastaddr and curaddr == curpbaddr and
  			 * lastaddr != lastpbaddr
  			 */
  			if (curaddr < lastaddr ||
  			    (curaddr == lastaddr && curaddr == curpbaddr &&
  			     lastaddr != lastpbaddr)) {
  				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)
  					/*
  					 * 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 range: %016Lx - %016Lx ",
  		       (unsigned long long) start,
  		       (unsigned long long) end);
  	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 real_removed_size = 0;
  
  	if (size > (ULLONG_MAX - start))
  		size = ULLONG_MAX - start;
  
  	for (i = 0; i < e820.nr_map; i++) {
  		struct e820entry *ei = &e820.map[i];
  		u64 final_start, final_end;
  
  		if (checktype && ei->type != old_type)
  			continue;
  		/* totally covered? */
  		if (ei->addr >= start &&
  		    (ei->addr + ei->size) <= (start + size)) {
  			real_removed_size += ei->size;
  			memset(ei, 0, sizeof(struct e820entry));
  			continue;
  		}
  		/* partially covered */
  		final_start = max(start, ei->addr);
  		final_end = min(start + size, ei->addr + ei->size);
  		if (final_start >= final_end)
  			continue;
  		real_removed_size += final_end - final_start;
  
  		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 "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
  	"PCI: Warning: Cannot find a gap in the 32bit address range\n"
  	"PCI: Unassigned devices with 32bit resource registers may break!\n");
  	}
  #endif
  
  	/*
  	 * e820_reserve_resources_late protect stolen RAM already
  	 */
  	pci_mem_start = gapstart;
  
  	printk(KERN_INFO
  	       "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
  	       pci_mem_start, gapstart, gapsize);
  }
  
  /**
   * Because of the size limitation of struct boot_params, only first
   * 128 E820 memory entries are passed to kernel via
   * boot_params.e820_map, others are passed via SETUP_E820_EXT node of
   * linked list of struct setup_data, which is parsed here.
   */
  void __init parse_e820_ext(struct setup_data *sdata, unsigned long pa_data)
  {
  	u32 map_len;
  	int entries;
  	struct e820entry *extmap;
  
  	entries = sdata->len / sizeof(struct e820entry);
  	map_len = sdata->len + sizeof(struct setup_data);
  	if (map_len > PAGE_SIZE)
  		sdata = early_ioremap(pa_data, map_len);
  	extmap = (struct e820entry *)(sdata->data);
  	__append_e820_map(extmap, entries);
  	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
  	if (map_len > PAGE_SIZE)
  		early_iounmap(sdata, map_len);
  	printk(KERN_INFO "extended physical RAM map:\n");
  	e820_print_map("extended");
  }
  
  #if defined(CONFIG_X86_64) || \
  	(defined(CONFIG_X86_32) && defined(CONFIG_HIBERNATION))
  /**
   * Find the ranges of physical addresses that do not correspond to
   * e820 RAM areas and mark the corresponding pages as nosave for
   * hibernation (32 bit) or software suspend and suspend to RAM (64 bit).
   *
   * This function requires the e820 map to be sorted and without any
   * overlapping entries and assumes the first e820 area to be RAM.
   */
  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_HIBERNATION
  /**
   * Mark ACPI NVS memory region, so that we can save/restore it during
   * hibernation and the subsequent resume.
   */
  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)
  			hibernate_nvs_register(ei->addr, ei->size);
  	}
  
  	return 0;
  }
  core_initcall(e820_mark_nvs_memory);
  #endif
  
  /*
   * Early reserved memory areas.
   */
  #define MAX_EARLY_RES 20
  
  struct early_res {
  	u64 start, end;
  	char name[16];
  	char overlap_ok;
  };
  static struct early_res early_res[MAX_EARLY_RES] __initdata = {
  	{ 0, PAGE_SIZE, "BIOS data page" },	/* BIOS data page */
  	{}
  };
  
  static int __init find_overlapped_early(u64 start, u64 end)
  {
  	int i;
  	struct early_res *r;
  
  	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
  		r = &early_res[i];
  		if (end > r->start && start < r->end)
  			break;
  	}
  
  	return i;
  }
  
  /*
   * Drop the i-th range from the early reservation map,
   * by copying any higher ranges down one over it, and
   * clearing what had been the last slot.
   */
  static void __init drop_range(int i)
  {
  	int j;
  
  	for (j = i + 1; j < MAX_EARLY_RES && early_res[j].end; j++)
  		;
  
  	memmove(&early_res[i], &early_res[i + 1],
  	       (j - 1 - i) * sizeof(struct early_res));
  
  	early_res[j - 1].end = 0;
  }
  
  /*
   * Split any existing ranges that:
   *  1) are marked 'overlap_ok', and
   *  2) overlap with the stated range [start, end)
   * into whatever portion (if any) of the existing range is entirely
   * below or entirely above the stated range.  Drop the portion
   * of the existing range that overlaps with the stated range,
   * which will allow the caller of this routine to then add that
   * stated range without conflicting with any existing range.
   */
  static void __init drop_overlaps_that_are_ok(u64 start, u64 end)
  {
  	int i;
  	struct early_res *r;
  	u64 lower_start, lower_end;
  	u64 upper_start, upper_end;
  	char name[16];
  
  	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
  		r = &early_res[i];
  
  		/* Continue past non-overlapping ranges */
  		if (end <= r->start || start >= r->end)
  			continue;
  
  		/*
  		 * Leave non-ok overlaps as is; let caller
  		 * panic "Overlapping early reservations"
  		 * when it hits this overlap.
  		 */
  		if (!r->overlap_ok)
  			return;
  
  		/*
  		 * We have an ok overlap.  We will drop it from the early
  		 * reservation map, and add back in any non-overlapping
  		 * portions (lower or upper) as separate, overlap_ok,
  		 * non-overlapping ranges.
  		 */
  
  		/* 1. Note any non-overlapping (lower or upper) ranges. */
  		strncpy(name, r->name, sizeof(name) - 1);
  
  		lower_start = lower_end = 0;
  		upper_start = upper_end = 0;
  		if (r->start < start) {
  		 	lower_start = r->start;
  			lower_end = start;
  		}
  		if (r->end > end) {
  			upper_start = end;
  			upper_end = r->end;
  		}
  
  		/* 2. Drop the original ok overlapping range */
  		drop_range(i);
  
  		i--;		/* resume for-loop on copied down entry */
  
  		/* 3. Add back in any non-overlapping ranges. */
  		if (lower_end)
  			reserve_early_overlap_ok(lower_start, lower_end, name);
  		if (upper_end)
  			reserve_early_overlap_ok(upper_start, upper_end, name);
  	}
  }
  
  static void __init __reserve_early(u64 start, u64 end, char *name,
  						int overlap_ok)
  {
  	int i;
  	struct early_res *r;
  
  	i = find_overlapped_early(start, end);
  	if (i >= MAX_EARLY_RES)
  		panic("Too many early reservations");
  	r = &early_res[i];
  	if (r->end)
  		panic("Overlapping early reservations "
  		      "%llx-%llx %s to %llx-%llx %s\n",
  		      start, end - 1, name?name:"", r->start,
  		      r->end - 1, r->name);
  	r->start = start;
  	r->end = end;
  	r->overlap_ok = overlap_ok;
  	if (name)
  		strncpy(r->name, name, sizeof(r->name) - 1);
  }
  
  /*
   * A few early reservtations come here.
   *
   * The 'overlap_ok' in the name of this routine does -not- mean it
   * is ok for these reservations to overlap an earlier reservation.
   * Rather it means that it is ok for subsequent reservations to
   * overlap this one.
   *
   * Use this entry point to reserve early ranges when you are doing
   * so out of "Paranoia", reserving perhaps more memory than you need,
   * just in case, and don't mind a subsequent overlapping reservation
   * that is known to be needed.
   *
   * The drop_overlaps_that_are_ok() call here isn't really needed.
   * It would be needed if we had two colliding 'overlap_ok'
   * reservations, so that the second such would not panic on the
   * overlap with the first.  We don't have any such as of this
   * writing, but might as well tolerate such if it happens in
   * the future.
   */
  void __init reserve_early_overlap_ok(u64 start, u64 end, char *name)
  {
  	drop_overlaps_that_are_ok(start, end);
  	__reserve_early(start, end, name, 1);
  }
  
  /*
   * Most early reservations come here.
   *
   * We first have drop_overlaps_that_are_ok() drop any pre-existing
   * 'overlap_ok' ranges, so that we can then reserve this memory
   * range without risk of panic'ing on an overlapping overlap_ok
   * early reservation.
   */
  void __init reserve_early(u64 start, u64 end, char *name)
  {
  	if (start >= end)
  		return;
  
  	drop_overlaps_that_are_ok(start, end);
  	__reserve_early(start, end, name, 0);
  }
  
  void __init free_early(u64 start, u64 end)
  {
  	struct early_res *r;
  	int i;
  
  	i = find_overlapped_early(start, end);
  	r = &early_res[i];
  	if (i >= MAX_EARLY_RES || r->end != end || r->start != start)
  		panic("free_early on not reserved area: %llx-%llx!",
  			 start, end - 1);
  
  	drop_range(i);
  }
  
  void __init early_res_to_bootmem(u64 start, u64 end)
  {
  	int i, count;
  	u64 final_start, final_end;
  
  	count  = 0;
  	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++)
  		count++;
  
  	printk(KERN_INFO "(%d early reservations) ==> bootmem [%010llx - %010llx]\n",
  			 count, start, end);
  	for (i = 0; i < count; i++) {
  		struct early_res *r = &early_res[i];
  		printk(KERN_INFO "  #%d [%010llx - %010llx] %16s", i,
  			r->start, r->end, r->name);
  		final_start = max(start, r->start);
  		final_end = min(end, r->end);
  		if (final_start >= final_end) {
  			printk(KERN_CONT "\n");
  			continue;
  		}
  		printk(KERN_CONT " ==> [%010llx - %010llx]\n",
  			final_start, final_end);
  		reserve_bootmem_generic(final_start, final_end - final_start,
  				BOOTMEM_DEFAULT);
  	}
  }
  
  /* Check for already reserved areas */
  static inline int __init bad_addr(u64 *addrp, u64 size, u64 align)
  {
  	int i;
  	u64 addr = *addrp;
  	int changed = 0;
  	struct early_res *r;
  again:
  	i = find_overlapped_early(addr, addr + size);
  	r = &early_res[i];
  	if (i < MAX_EARLY_RES && r->end) {
  		*addrp = addr = round_up(r->end, align);
  		changed = 1;
  		goto again;
  	}
  	return changed;
  }
  
  /* Check for already reserved areas */
  static inline int __init bad_addr_size(u64 *addrp, u64 *sizep, u64 align)
  {
  	int i;
  	u64 addr = *addrp, last;
  	u64 size = *sizep;
  	int changed = 0;
  again:
  	last = addr + size;
  	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
  		struct early_res *r = &early_res[i];
  		if (last > r->start && addr < r->start) {
  			size = r->start - addr;
  			changed = 1;
  			goto again;
  		}
  		if (last > r->end && addr < r->end) {
  			addr = round_up(r->end, align);
  			size = last - addr;
  			changed = 1;
  			goto again;
  		}
  		if (last <= r->end && addr >= r->start) {
  			(*sizep)++;
  			return 0;
  		}
  	}
  	if (changed) {
  		*addrp = addr;
  		*sizep = size;
  	}
  	return changed;
  }
  
  /*
   * Find a free area with specified alignment in a specific range.
   */
  u64 __init find_e820_area(u64 start, u64 end, u64 size, u64 align)
  {
  	int i;
  
  	for (i = 0; i < e820.nr_map; i++) {
  		struct e820entry *ei = &e820.map[i];
  		u64 addr, last;
  		u64 ei_last;
  
  		if (ei->type != E820_RAM)
  			continue;
  		addr = round_up(ei->addr, align);
  		ei_last = ei->addr + ei->size;
  		if (addr < start)
  			addr = round_up(start, align);
  		if (addr >= ei_last)
  			continue;
  		while (bad_addr(&addr, size, align) && addr+size <= ei_last)
  			;
  		last = addr + size;
  		if (last > ei_last)
  			continue;
  		if (last > end)
  			continue;
  		return addr;
  	}
  	return -1ULL;
  }
  
  /*
   * Find next free range after *start
   */
  u64 __init find_e820_area_size(u64 start, u64 *sizep, u64 align)
  {
  	int i;
  
  	for (i = 0; i < e820.nr_map; i++) {
  		struct e820entry *ei = &e820.map[i];
  		u64 addr, last;
  		u64 ei_last;
  
  		if (ei->type != E820_RAM)
  			continue;
  		addr = round_up(ei->addr, align);
  		ei_last = ei->addr + ei->size;
  		if (addr < start)
  			addr = round_up(start, align);
  		if (addr >= ei_last)
  			continue;
  		*sizep = ei_last - addr;
  		while (bad_addr_size(&addr, sizep, align) &&
  			addr + *sizep <= ei_last)
  			;
  		last = addr + *sizep;
  		if (last > ei_last)
  			continue;
  		return addr;
  	}
  
  	return -1ULL;
  }
  
  /*
   * pre allocated 4k and reserved it in e820
   */
  u64 __init early_reserve_e820(u64 startt, u64 sizet, u64 align)
  {
  	u64 size = 0;
  	u64 addr;
  	u64 start;
  
  	for (start = startt; ; start += size) {
  		start = find_e820_area_size(start, &size, align);
  		if (!(start + 1))
  			return 0;
  		if (size >= sizet)
  			break;
  	}
  
  #ifdef CONFIG_X86_32
  	if (start >= MAXMEM)
  		return 0;
  	if (start + size > MAXMEM)
  		size = MAXMEM - start;
  #endif
  
  	addr = round_down(start + size - sizet, align);
  	if (addr < start)
  		return 0;
  	e820_update_range(addr, sizet, E820_RAM, E820_RESERVED);
  	e820_update_range_saved(addr, sizet, E820_RAM, E820_RESERVED);
  	printk(KERN_INFO "update e820 for early_reserve_e820\n");
  	update_e820();
  	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 "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);
  }
  /*
   * Finds an active region in the address range from start_pfn to last_pfn and
   * returns its range in ei_startpfn and ei_endpfn for the e820 entry.
   */
  int __init e820_find_active_region(const struct e820entry *ei,
  				  unsigned long start_pfn,
  				  unsigned long last_pfn,
  				  unsigned long *ei_startpfn,
  				  unsigned long *ei_endpfn)
  {
  	u64 align = PAGE_SIZE;
  
  	*ei_startpfn = round_up(ei->addr, align) >> PAGE_SHIFT;
  	*ei_endpfn = round_down(ei->addr + ei->size, align) >> PAGE_SHIFT;
  
  	/* Skip map entries smaller than a page */
  	if (*ei_startpfn >= *ei_endpfn)
  		return 0;
  
  	/* Skip if map is outside the node */
  	if (ei->type != E820_RAM || *ei_endpfn <= start_pfn ||
  				    *ei_startpfn >= last_pfn)
  		return 0;
  
  	/* Check for overlaps */
  	if (*ei_startpfn < start_pfn)
  		*ei_startpfn = start_pfn;
  	if (*ei_endpfn > last_pfn)
  		*ei_endpfn = last_pfn;
  
  	return 1;
  }
  
  /* Walk the e820 map and register active regions within a node */
  void __init e820_register_active_regions(int nid, unsigned long start_pfn,
  					 unsigned long last_pfn)
  {
  	unsigned long ei_startpfn;
  	unsigned long ei_endpfn;
  	int i;
  
  	for (i = 0; i < e820.nr_map; i++)
  		if (e820_find_active_region(&e820.map[i],
  					    start_pfn, last_pfn,
  					    &ei_startpfn, &ei_endpfn))
  			add_active_range(nid, ei_startpfn, ei_endpfn);
  }
  
  /*
   * Find the hole size (in bytes) in the memory range.
   * @start: starting address of the memory range to scan
   * @end: ending address of the memory range to scan
   */
  u64 __init e820_hole_size(u64 start, u64 end)
  {
  	unsigned long start_pfn = start >> PAGE_SHIFT;
  	unsigned long last_pfn = end >> PAGE_SHIFT;
  	unsigned long ei_startpfn, ei_endpfn, ram = 0;
  	int i;
  
  	for (i = 0; i < e820.nr_map; i++) {
  		if (e820_find_active_region(&e820.map[i],
  					    start_pfn, last_pfn,
  					    &ei_startpfn, &ei_endpfn))
  			ram += ei_endpfn - ei_startpfn;
  	}
  	return end - start - ((u64)ram << PAGE_SHIFT);
  }
  
  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;
  
  #ifdef CONFIG_X86_32
  	if (!strcmp(p, "nopentium")) {
  		setup_clear_cpu_cap(X86_FEATURE_PSE);
  		return 0;
  	}
  #endif
  
  	userdef = 1;
  	mem_size = memparse(p, &p);
  	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 "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 - 1,
  			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;
  		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 "BIOS-provided physical RAM map:\n");
  	e820_print_map(who);
  }
  