Merge branch 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6

* 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6: (156 commits)
  [PATCH] x86-64: Export smp_call_function_single
  [PATCH] i386: Clean up smp_tune_scheduling()
  [PATCH] unwinder: move .eh_frame to RODATA
  [PATCH] unwinder: fully support linker generated .eh_frame_hdr section
  [PATCH] x86-64: don't use set_irq_regs()
  [PATCH] x86-64: check vector in setup_ioapic_dest to verify if need setup_IO_APIC_irq
  [PATCH] x86-64: Make ix86 default to HIGHMEM4G instead of NOHIGHMEM
  [PATCH] i386: replace kmalloc+memset with kzalloc
  [PATCH] x86-64: remove remaining pc98 code
  [PATCH] x86-64: remove unused variable
  [PATCH] x86-64: Fix constraints in atomic_add_return()
  [PATCH] x86-64: fix asm constraints in i386 atomic_add_return
  [PATCH] x86-64: Correct documentation for bzImage protocol v2.05
  [PATCH] x86-64: replace kmalloc+memset with kzalloc in MTRR code
  [PATCH] x86-64: Fix numaq build error
  [PATCH] x86-64: include/asm-x86_64/cpufeature.h isn't a userspace header
  [PATCH] unwinder: Add debugging output to the Dwarf2 unwinder
  [PATCH] x86-64: Clarify error message in GART code
  [PATCH] x86-64: Fix interrupt race in idle callback (3rd try)
  [PATCH] x86-64: Remove unwind stack pointer alignment forcing again
  ...

Fixed conflict in include/linux/uaccess.h manually

Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 894 insertions, 0 deletions

diff --git a/arch/i386/kernel/e820.c b/arch/i386/kernel/e820.c
new file mode 100644
index 000000000000..2f7d0a92fd7c
--- /dev/null
+++ b/arch/i386/kernel/e820.c
@@ -0,0 +1,894 @@
+#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>
+
+#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
+} };
+
+static int romsignature(const unsigned char *x)
+{
+	unsigned short sig;
+	int ret = 0;
+	if (probe_kernel_address((const unsigned short *)x, sig) == 0)
+		ret = (sig == 0xaa55);
+	return ret;
+}
+
+static int __init romchecksum(unsigned char *rom, unsigned long length)
+{
+	unsigned char *p, sum = 0;
+
+	for (p = rom; p < rom + length; p++)
+		sum += *p;
+	return sum == 0;
+}
+
+static void __init probe_roms(void)
+{
+	unsigned long start, length, upper;
+	unsigned char *rom;
+	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;
+
+		/* 0 < length <= 0x7f * 512, historically */
+		length = rom[2] * 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;
+
+		/* 0 < length <= 0x7f * 512, historically */
+		length = rom[2] * 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_
+	*/
+	printk("sanitize start\n");
+	/* if there's only one memory region, don't bother */
+	if (*pnr_map < 2) {
+		printk("sanitize bail 0\n");
+		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) {
+			printk("sanitize bail 1\n");
+			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;
+
+	printk("sanitize end\n");
+	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;
+		printk("copy_e820_map() start: %016Lx size: %016Lx end: %016Lx type: %ld\n", start, size, end, 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) {
+			printk("copy_e820_map() type is E820_RAM\n");
+			if (start < 0x100000ULL && end > 0xA0000ULL) {
+				printk("copy_e820_map() lies in range...\n");
+				if (start < 0xA0000ULL) {
+					printk("copy_e820_map() start < 0xA0000ULL\n");
+					add_memory_region(start, 0xA0000ULL-start, type);
+				}
+				if (end <= 0x100000ULL) {
+					printk("copy_e820_map() end <= 0x100000ULL\n");
+					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 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 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);