From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 11 Oct 2007 09:14:27 +0000 (+0200)
Subject: x86_64: prepare shared kernel/e820.c
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=b43312c45e51aa79d76850f85a5731f24c1b0d8d;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

x86_64: prepare shared kernel/e820.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/arch/x86_64/kernel/Makefile b/arch/x86_64/kernel/Makefile
index e717a324bd8a..e290dfa84004 100644
--- a/arch/x86_64/kernel/Makefile
+++ b/arch/x86_64/kernel/Makefile
@@ -7,7 +7,7 @@ EXTRA_AFLAGS	:= -traditional
 obj-y	:= process.o signal.o entry.o traps_64.o irq.o \
 		ptrace.o time.o ioport.o ldt.o setup.o i8259_64.o sys_x86_64.o \
 		x8664_ksyms.o i387.o syscall.o vsyscall.o \
-		setup64.o bootflag.o e820.o reboot.o quirks.o i8237.o \
+		setup64.o bootflag.o e820_64.o reboot.o quirks.o i8237.o \
 		pci-dma_64.o pci-nommu.o alternative.o hpet_64.o tsc.o bugs.o \
 		perfctr-watchdog.o
 
diff --git a/arch/x86_64/kernel/e820.c b/arch/x86_64/kernel/e820.c
deleted file mode 100644
index 0f4d5e209e9b..000000000000
--- a/arch/x86_64/kernel/e820.c
+++ /dev/null
@@ -1,725 +0,0 @@
-/* 
- * 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/suspend.h>
-#include <linux/pfn.h>
-
-#include <asm/pgtable.h>
-#include <asm/page.h>
-#include <asm/e820.h>
-#include <asm/proto.h>
-#include <asm/bootsetup.h>
-#include <asm/sections.h>
-
-struct e820map e820;
-
-/* 
- * PFN of last memory page.
- */
-unsigned long end_pfn; 
-EXPORT_SYMBOL(end_pfn);
-
-/* 
- * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
- * The direct mapping extends to end_pfn_map, so that we can directly access
- * apertures, ACPI and other tables without having to play with fixmaps.
- */ 
-unsigned long end_pfn_map; 
-
-/* 
- * Last pfn which the user wants to use.
- */
-static unsigned long __initdata end_user_pfn = MAXMEM>>PAGE_SHIFT;
-
-extern struct resource code_resource, data_resource;
-
-/* Check for some hardcoded bad areas that early boot is not allowed to touch */ 
-static inline int bad_addr(unsigned long *addrp, unsigned long size)
-{ 
-	unsigned long addr = *addrp, last = addr + size; 
-
-	/* various gunk below that needed for SMP startup */
-	if (addr < 0x8000) { 
-		*addrp = PAGE_ALIGN(0x8000);
-		return 1; 
-	}
-
-	/* direct mapping tables of the kernel */
-	if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) { 
-		*addrp = PAGE_ALIGN(table_end << PAGE_SHIFT);
-		return 1;
-	} 
-
-	/* initrd */ 
-#ifdef CONFIG_BLK_DEV_INITRD
-	if (LOADER_TYPE && INITRD_START && last >= INITRD_START && 
-	    addr < INITRD_START+INITRD_SIZE) { 
-		*addrp = PAGE_ALIGN(INITRD_START + INITRD_SIZE);
-		return 1;
-	} 
-#endif
-	/* kernel code */
-	if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) {
-		*addrp = PAGE_ALIGN(__pa_symbol(&_end));
-		return 1;
-	}
-
-	if (last >= ebda_addr && addr < ebda_addr + ebda_size) {
-		*addrp = PAGE_ALIGN(ebda_addr + ebda_size);
-		return 1;
-	}
-
-#ifdef CONFIG_NUMA
-	/* NUMA memory to node map */
-	if (last >= nodemap_addr && addr < nodemap_addr + nodemap_size) {
-		*addrp = nodemap_addr + nodemap_size;
-		return 1;
-	}
-#endif
-	/* XXX ramdisk image here? */ 
-	return 0;
-} 
-
-/*
- * This function checks if any part of the range <start,end> is mapped
- * with type.
- */
-int
-e820_any_mapped(unsigned long start, unsigned long 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(unsigned long start, unsigned long 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; /* we're done */
-	}
-	return 0;
-}
-
-/* 
- * Find a free area in a specific range. 
- */ 
-unsigned long __init find_e820_area(unsigned long start, unsigned long end, unsigned size) 
-{ 
-	int i; 
-	for (i = 0; i < e820.nr_map; i++) { 
-		struct e820entry *ei = &e820.map[i]; 
-		unsigned long addr = ei->addr, last; 
-		if (ei->type != E820_RAM) 
-			continue; 
-		if (addr < start) 
-			addr = start;
-		if (addr > ei->addr + ei->size) 
-			continue; 
-		while (bad_addr(&addr, size) && addr+size <= ei->addr+ei->size)
-			;
-		last = PAGE_ALIGN(addr) + size;
-		if (last > ei->addr + ei->size)
-			continue;
-		if (last > end) 
-			continue;
-		return addr; 
-	} 
-	return -1UL;		
-} 
-
-/*
- * Find the highest page frame number we have available
- */
-unsigned long __init e820_end_of_ram(void)
-{
-	unsigned long end_pfn = 0;
-	end_pfn = find_max_pfn_with_active_regions();
-	
-	if (end_pfn > end_pfn_map) 
-		end_pfn_map = end_pfn;
-	if (end_pfn_map > MAXMEM>>PAGE_SHIFT)
-		end_pfn_map = MAXMEM>>PAGE_SHIFT;
-	if (end_pfn > end_user_pfn)
-		end_pfn = end_user_pfn;
-	if (end_pfn > end_pfn_map) 
-		end_pfn = end_pfn_map; 
-
-	printk("end_pfn_map = %lu\n", end_pfn_map);
-	return end_pfn;	
-}
-
-/*
- * Mark e820 reserved areas as busy for the resource manager.
- */
-void __init e820_reserve_resources(void)
-{
-	int i;
-	for (i = 0; i < e820.nr_map; i++) {
-		struct resource *res;
-		res = alloc_bootmem_low(sizeof(struct resource));
-		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;
-		request_resource(&iomem_resource, res);
-		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
-		}
-	}
-}
-
-/*
- * Find the ranges of physical addresses that do not correspond to
- * e820 RAM areas and mark the corresponding pages as nosave for software
- * suspend and suspend to RAM.
- *
- * 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(void)
-{
-	int i;
-	unsigned long paddr;
-
-	paddr = round_down(e820.map[0].addr + e820.map[0].size, PAGE_SIZE);
-	for (i = 1; i < e820.nr_map; i++) {
-		struct e820entry *ei = &e820.map[i];
-
-		if (paddr < ei->addr)
-			register_nosave_region(PFN_DOWN(paddr),
-						PFN_UP(ei->addr));
-
-		paddr = round_down(ei->addr + ei->size, PAGE_SIZE);
-		if (ei->type != E820_RAM)
-			register_nosave_region(PFN_UP(ei->addr),
-						PFN_DOWN(paddr));
-
-		if (paddr >= (end_pfn << PAGE_SHIFT))
-			break;
-	}
-}
-
-/*
- * Finds an active region in the address range from start_pfn to end_pfn and
- * returns its range in ei_startpfn and ei_endpfn for the e820 entry.
- */
-static int __init e820_find_active_region(const struct e820entry *ei,
-					  unsigned long start_pfn,
-					  unsigned long end_pfn,
-					  unsigned long *ei_startpfn,
-					  unsigned long *ei_endpfn)
-{
-	*ei_startpfn = round_up(ei->addr, PAGE_SIZE) >> PAGE_SHIFT;
-	*ei_endpfn = round_down(ei->addr + ei->size, PAGE_SIZE) >> PAGE_SHIFT;
-
-	/* Skip map entries smaller than a page */
-	if (*ei_startpfn >= *ei_endpfn)
-		return 0;
-
-	/* Check if end_pfn_map should be updated */
-	if (ei->type != E820_RAM && *ei_endpfn > end_pfn_map)
-		end_pfn_map = *ei_endpfn;
-
-	/* Skip if map is outside the node */
-	if (ei->type != E820_RAM || *ei_endpfn <= start_pfn ||
-				    *ei_startpfn >= end_pfn)
-		return 0;
-
-	/* Check for overlaps */
-	if (*ei_startpfn < start_pfn)
-		*ei_startpfn = start_pfn;
-	if (*ei_endpfn > end_pfn)
-		*ei_endpfn = end_pfn;
-
-	/* Obey end_user_pfn to save on memmap */
-	if (*ei_startpfn >= end_user_pfn)
-		return 0;
-	if (*ei_endpfn > end_user_pfn)
-		*ei_endpfn = end_user_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 end_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, end_pfn,
-					    &ei_startpfn, &ei_endpfn))
-			add_active_range(nid, ei_startpfn, ei_endpfn);
-}
-
-/* 
- * Add a memory region to the kernel e820 map.
- */ 
-void __init add_memory_region(unsigned long start, unsigned long size, int type)
-{
-	int 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++;
-}
-
-/*
- * 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
- */
-unsigned long __init e820_hole_size(unsigned long start, unsigned long end)
-{
-	unsigned long start_pfn = start >> PAGE_SHIFT;
-	unsigned long end_pfn = end >> PAGE_SHIFT;
-	unsigned long ei_startpfn;
-	unsigned long ei_endpfn;
-	unsigned long ram = 0;
-	int i;
-
-	for (i = 0; i < e820.nr_map; i++) {
-		if (e820_find_active_region(&e820.map[i],
-					    start_pfn, end_pfn,
-					    &ei_startpfn, &ei_endpfn))
-			ram += ei_endpfn - ei_startpfn;
-	}
-	return end - start - (ram << PAGE_SHIFT);
-}
-
-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));
-		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 %u\n", e820.map[i].type);
-				break;
-		}
-	}
-}
-
-/*
- * Sanitize the BIOS e820 map.
- *
- * Some e820 responses include overlapping entries.  The following 
- * replaces the original e820 map with a new one, removing overlaps.
- *
- */
-static int __init sanitize_e820_map(struct e820entry * biosmap, char * 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*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;
-	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;
-
-	/* 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.
- */
-static 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 start = biosmap->addr;
-		unsigned long size = biosmap->size;
-		unsigned long end = start + size;
-		unsigned long type = biosmap->type;
-
-		/* Overflow in 64 bits? Ignore the memory map. */
-		if (start > end)
-			return -1;
-
-		add_memory_region(start, size, type);
-	} while (biosmap++,--nr_map);
-	return 0;
-}
-
-void early_panic(char *msg)
-{
-	early_printk(msg);
-	panic(msg);
-}
-
-void __init setup_memory_region(void)
-{
-	/*
-	 * 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
-	 */
-	sanitize_e820_map(E820_MAP, &E820_MAP_NR);
-	if (copy_e820_map(E820_MAP, E820_MAP_NR) < 0)
-		early_panic("Cannot find a valid memory map");
-	printk(KERN_INFO "BIOS-provided physical RAM map:\n");
-	e820_print_map("BIOS-e820");
-}
-
-static int __init parse_memopt(char *p)
-{
-	if (!p)
-		return -EINVAL;
-	end_user_pfn = memparse(p, &p);
-	end_user_pfn >>= PAGE_SHIFT;	
-	return 0;
-} 
-early_param("mem", parse_memopt);
-
-static int userdef __initdata;
-
-static int __init parse_memmap_opt(char *p)
-{
-	char *oldp;
-	unsigned long long start_at, mem_size;
-
-	if (!strcmp(p, "exactmap")) {
-#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.
-		 */
-		e820_register_active_regions(0, 0, -1UL);
-		saved_max_pfn = e820_end_of_ram();
-		remove_all_active_ranges();
-#endif
-		end_pfn_map = 0;
-		e820.nr_map = 0;
-		userdef = 1;
-		return 0;
-	}
-
-	oldp = p;
-	mem_size = memparse(p, &p);
-	if (p == oldp)
-		return -EINVAL;
-	if (*p == '@') {
-		start_at = memparse(p+1, &p);
-		add_memory_region(start_at, mem_size, E820_RAM);
-	} else if (*p == '#') {
-		start_at = memparse(p+1, &p);
-		add_memory_region(start_at, mem_size, E820_ACPI);
-	} else if (*p == '$') {
-		start_at = memparse(p+1, &p);
-		add_memory_region(start_at, mem_size, E820_RESERVED);
-	} else {
-		end_user_pfn = (mem_size >> PAGE_SHIFT);
-	}
-	return *p == '\0' ? 0 : -EINVAL;
-}
-early_param("memmap", parse_memmap_opt);
-
-void __init finish_e820_parsing(void)
-{
-	if (userdef) {
-		printk(KERN_INFO "user-defined physical RAM map:\n");
-		e820_print_map("user");
-	}
-}
-
-unsigned long pci_mem_start = 0xaeedbabe;
-EXPORT_SYMBOL(pci_mem_start);
-
-/*
- * 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, round;
-	unsigned long last;
-	int i;
-	int found = 0;
-
-	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;
-				found = 1;
-			}
-		}
-		if (start < last)
-			last = start;
-	}
-
-	if (!found) {
-		gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
-		printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit address range\n"
-		       KERN_ERR "PCI: Unassigned devices with 32bit resource registers may break!\n");
-	}
-
-	/*
-	 * 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(KERN_INFO "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
-		pci_mem_start, gapstart, gapsize);
-}
diff --git a/arch/x86_64/kernel/e820_64.c b/arch/x86_64/kernel/e820_64.c
new file mode 100644
index 000000000000..0f4d5e209e9b
--- /dev/null
+++ b/arch/x86_64/kernel/e820_64.c
@@ -0,0 +1,725 @@
+/* 
+ * 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/suspend.h>
+#include <linux/pfn.h>
+
+#include <asm/pgtable.h>
+#include <asm/page.h>
+#include <asm/e820.h>
+#include <asm/proto.h>
+#include <asm/bootsetup.h>
+#include <asm/sections.h>
+
+struct e820map e820;
+
+/* 
+ * PFN of last memory page.
+ */
+unsigned long end_pfn; 
+EXPORT_SYMBOL(end_pfn);
+
+/* 
+ * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
+ * The direct mapping extends to end_pfn_map, so that we can directly access
+ * apertures, ACPI and other tables without having to play with fixmaps.
+ */ 
+unsigned long end_pfn_map; 
+
+/* 
+ * Last pfn which the user wants to use.
+ */
+static unsigned long __initdata end_user_pfn = MAXMEM>>PAGE_SHIFT;
+
+extern struct resource code_resource, data_resource;
+
+/* Check for some hardcoded bad areas that early boot is not allowed to touch */ 
+static inline int bad_addr(unsigned long *addrp, unsigned long size)
+{ 
+	unsigned long addr = *addrp, last = addr + size; 
+
+	/* various gunk below that needed for SMP startup */
+	if (addr < 0x8000) { 
+		*addrp = PAGE_ALIGN(0x8000);
+		return 1; 
+	}
+
+	/* direct mapping tables of the kernel */
+	if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) { 
+		*addrp = PAGE_ALIGN(table_end << PAGE_SHIFT);
+		return 1;
+	} 
+
+	/* initrd */ 
+#ifdef CONFIG_BLK_DEV_INITRD
+	if (LOADER_TYPE && INITRD_START && last >= INITRD_START && 
+	    addr < INITRD_START+INITRD_SIZE) { 
+		*addrp = PAGE_ALIGN(INITRD_START + INITRD_SIZE);
+		return 1;
+	} 
+#endif
+	/* kernel code */
+	if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) {
+		*addrp = PAGE_ALIGN(__pa_symbol(&_end));
+		return 1;
+	}
+
+	if (last >= ebda_addr && addr < ebda_addr + ebda_size) {
+		*addrp = PAGE_ALIGN(ebda_addr + ebda_size);
+		return 1;
+	}
+
+#ifdef CONFIG_NUMA
+	/* NUMA memory to node map */
+	if (last >= nodemap_addr && addr < nodemap_addr + nodemap_size) {
+		*addrp = nodemap_addr + nodemap_size;
+		return 1;
+	}
+#endif
+	/* XXX ramdisk image here? */ 
+	return 0;
+} 
+
+/*
+ * This function checks if any part of the range <start,end> is mapped
+ * with type.
+ */
+int
+e820_any_mapped(unsigned long start, unsigned long 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(unsigned long start, unsigned long 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; /* we're done */
+	}
+	return 0;
+}
+
+/* 
+ * Find a free area in a specific range. 
+ */ 
+unsigned long __init find_e820_area(unsigned long start, unsigned long end, unsigned size) 
+{ 
+	int i; 
+	for (i = 0; i < e820.nr_map; i++) { 
+		struct e820entry *ei = &e820.map[i]; 
+		unsigned long addr = ei->addr, last; 
+		if (ei->type != E820_RAM) 
+			continue; 
+		if (addr < start) 
+			addr = start;
+		if (addr > ei->addr + ei->size) 
+			continue; 
+		while (bad_addr(&addr, size) && addr+size <= ei->addr+ei->size)
+			;
+		last = PAGE_ALIGN(addr) + size;
+		if (last > ei->addr + ei->size)
+			continue;
+		if (last > end) 
+			continue;
+		return addr; 
+	} 
+	return -1UL;		
+} 
+
+/*
+ * Find the highest page frame number we have available
+ */
+unsigned long __init e820_end_of_ram(void)
+{
+	unsigned long end_pfn = 0;
+	end_pfn = find_max_pfn_with_active_regions();
+	
+	if (end_pfn > end_pfn_map) 
+		end_pfn_map = end_pfn;
+	if (end_pfn_map > MAXMEM>>PAGE_SHIFT)
+		end_pfn_map = MAXMEM>>PAGE_SHIFT;
+	if (end_pfn > end_user_pfn)
+		end_pfn = end_user_pfn;
+	if (end_pfn > end_pfn_map) 
+		end_pfn = end_pfn_map; 
+
+	printk("end_pfn_map = %lu\n", end_pfn_map);
+	return end_pfn;	
+}
+
+/*
+ * Mark e820 reserved areas as busy for the resource manager.
+ */
+void __init e820_reserve_resources(void)
+{
+	int i;
+	for (i = 0; i < e820.nr_map; i++) {
+		struct resource *res;
+		res = alloc_bootmem_low(sizeof(struct resource));
+		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;
+		request_resource(&iomem_resource, res);
+		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
+		}
+	}
+}
+
+/*
+ * Find the ranges of physical addresses that do not correspond to
+ * e820 RAM areas and mark the corresponding pages as nosave for software
+ * suspend and suspend to RAM.
+ *
+ * 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(void)
+{
+	int i;
+	unsigned long paddr;
+
+	paddr = round_down(e820.map[0].addr + e820.map[0].size, PAGE_SIZE);
+	for (i = 1; i < e820.nr_map; i++) {
+		struct e820entry *ei = &e820.map[i];
+
+		if (paddr < ei->addr)
+			register_nosave_region(PFN_DOWN(paddr),
+						PFN_UP(ei->addr));
+
+		paddr = round_down(ei->addr + ei->size, PAGE_SIZE);
+		if (ei->type != E820_RAM)
+			register_nosave_region(PFN_UP(ei->addr),
+						PFN_DOWN(paddr));
+
+		if (paddr >= (end_pfn << PAGE_SHIFT))
+			break;
+	}
+}
+
+/*
+ * Finds an active region in the address range from start_pfn to end_pfn and
+ * returns its range in ei_startpfn and ei_endpfn for the e820 entry.
+ */
+static int __init e820_find_active_region(const struct e820entry *ei,
+					  unsigned long start_pfn,
+					  unsigned long end_pfn,
+					  unsigned long *ei_startpfn,
+					  unsigned long *ei_endpfn)
+{
+	*ei_startpfn = round_up(ei->addr, PAGE_SIZE) >> PAGE_SHIFT;
+	*ei_endpfn = round_down(ei->addr + ei->size, PAGE_SIZE) >> PAGE_SHIFT;
+
+	/* Skip map entries smaller than a page */
+	if (*ei_startpfn >= *ei_endpfn)
+		return 0;
+
+	/* Check if end_pfn_map should be updated */
+	if (ei->type != E820_RAM && *ei_endpfn > end_pfn_map)
+		end_pfn_map = *ei_endpfn;
+
+	/* Skip if map is outside the node */
+	if (ei->type != E820_RAM || *ei_endpfn <= start_pfn ||
+				    *ei_startpfn >= end_pfn)
+		return 0;
+
+	/* Check for overlaps */
+	if (*ei_startpfn < start_pfn)
+		*ei_startpfn = start_pfn;
+	if (*ei_endpfn > end_pfn)
+		*ei_endpfn = end_pfn;
+
+	/* Obey end_user_pfn to save on memmap */
+	if (*ei_startpfn >= end_user_pfn)
+		return 0;
+	if (*ei_endpfn > end_user_pfn)
+		*ei_endpfn = end_user_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 end_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, end_pfn,
+					    &ei_startpfn, &ei_endpfn))
+			add_active_range(nid, ei_startpfn, ei_endpfn);
+}
+
+/* 
+ * Add a memory region to the kernel e820 map.
+ */ 
+void __init add_memory_region(unsigned long start, unsigned long size, int type)
+{
+	int 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++;
+}
+
+/*
+ * 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
+ */
+unsigned long __init e820_hole_size(unsigned long start, unsigned long end)
+{
+	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long end_pfn = end >> PAGE_SHIFT;
+	unsigned long ei_startpfn;
+	unsigned long ei_endpfn;
+	unsigned long ram = 0;
+	int i;
+
+	for (i = 0; i < e820.nr_map; i++) {
+		if (e820_find_active_region(&e820.map[i],
+					    start_pfn, end_pfn,
+					    &ei_startpfn, &ei_endpfn))
+			ram += ei_endpfn - ei_startpfn;
+	}
+	return end - start - (ram << PAGE_SHIFT);
+}
+
+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));
+		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 %u\n", e820.map[i].type);
+				break;
+		}
+	}
+}
+
+/*
+ * Sanitize the BIOS e820 map.
+ *
+ * Some e820 responses include overlapping entries.  The following 
+ * replaces the original e820 map with a new one, removing overlaps.
+ *
+ */
+static int __init sanitize_e820_map(struct e820entry * biosmap, char * 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*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;
+	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;
+
+	/* 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.
+ */
+static 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 start = biosmap->addr;
+		unsigned long size = biosmap->size;
+		unsigned long end = start + size;
+		unsigned long type = biosmap->type;
+
+		/* Overflow in 64 bits? Ignore the memory map. */
+		if (start > end)
+			return -1;
+
+		add_memory_region(start, size, type);
+	} while (biosmap++,--nr_map);
+	return 0;
+}
+
+void early_panic(char *msg)
+{
+	early_printk(msg);
+	panic(msg);
+}
+
+void __init setup_memory_region(void)
+{
+	/*
+	 * 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
+	 */
+	sanitize_e820_map(E820_MAP, &E820_MAP_NR);
+	if (copy_e820_map(E820_MAP, E820_MAP_NR) < 0)
+		early_panic("Cannot find a valid memory map");
+	printk(KERN_INFO "BIOS-provided physical RAM map:\n");
+	e820_print_map("BIOS-e820");
+}
+
+static int __init parse_memopt(char *p)
+{
+	if (!p)
+		return -EINVAL;
+	end_user_pfn = memparse(p, &p);
+	end_user_pfn >>= PAGE_SHIFT;	
+	return 0;
+} 
+early_param("mem", parse_memopt);
+
+static int userdef __initdata;
+
+static int __init parse_memmap_opt(char *p)
+{
+	char *oldp;
+	unsigned long long start_at, mem_size;
+
+	if (!strcmp(p, "exactmap")) {
+#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.
+		 */
+		e820_register_active_regions(0, 0, -1UL);
+		saved_max_pfn = e820_end_of_ram();
+		remove_all_active_ranges();
+#endif
+		end_pfn_map = 0;
+		e820.nr_map = 0;
+		userdef = 1;
+		return 0;
+	}
+
+	oldp = p;
+	mem_size = memparse(p, &p);
+	if (p == oldp)
+		return -EINVAL;
+	if (*p == '@') {
+		start_at = memparse(p+1, &p);
+		add_memory_region(start_at, mem_size, E820_RAM);
+	} else if (*p == '#') {
+		start_at = memparse(p+1, &p);
+		add_memory_region(start_at, mem_size, E820_ACPI);
+	} else if (*p == '$') {
+		start_at = memparse(p+1, &p);
+		add_memory_region(start_at, mem_size, E820_RESERVED);
+	} else {
+		end_user_pfn = (mem_size >> PAGE_SHIFT);
+	}
+	return *p == '\0' ? 0 : -EINVAL;
+}
+early_param("memmap", parse_memmap_opt);
+
+void __init finish_e820_parsing(void)
+{
+	if (userdef) {
+		printk(KERN_INFO "user-defined physical RAM map:\n");
+		e820_print_map("user");
+	}
+}
+
+unsigned long pci_mem_start = 0xaeedbabe;
+EXPORT_SYMBOL(pci_mem_start);
+
+/*
+ * 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, round;
+	unsigned long last;
+	int i;
+	int found = 0;
+
+	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;
+				found = 1;
+			}
+		}
+		if (start < last)
+			last = start;
+	}
+
+	if (!found) {
+		gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
+		printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit address range\n"
+		       KERN_ERR "PCI: Unassigned devices with 32bit resource registers may break!\n");
+	}
+
+	/*
+	 * 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(KERN_INFO "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
+		pci_mem_start, gapstart, gapsize);
+}