Initial import

1 files changed, 1135 insertions, 0 deletions

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
new file mode 100644
index 000000000..e2ce85db2
--- /dev/null
+++ b/arch/x86/kernel/e820.c
@@ -0,0 +1,1135 @@
+/*
+ * 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/crash_dump.h>
+#include <linux/export.h>
+#include <linux/bootmem.h>
+#include <linux/pfn.h>
+#include <linux/suspend.h>
+#include <linux/acpi.h>
+#include <linux/firmware-map.h>
+#include <linux/memblock.h>
+#include <linux/sort.h>
+
+#include <asm/e820.h>
+#include <asm/proto.h>
+#include <asm/setup.h>
+
+/*
+ * The e820 map is the map that gets modified e.g. with command line parameters
+ * and that is also registered with modifications in the kernel resource tree
+ * with the iomem_resource as parent.
+ *
+ * The e820_saved is directly saved after the BIOS-provided memory map is
+ * copied. It doesn't get modified afterwards. It's registered for the
+ * /sys/firmware/memmap interface.
+ *
+ * That memory map is not modified and is used as base for kexec. The kexec'd
+ * kernel should get the same memory map as the firmware provides. Then the
+ * user can e.g. boot the original kernel with mem=1G while still booting the
+ * next kernel with full memory.
+ */
+struct e820map e820;
+struct e820map e820_saved;
+
+/* For PCI or other memory-mapped resources */
+unsigned long pci_mem_start = 0xaeedbabe;
+#ifdef CONFIG_PCI
+EXPORT_SYMBOL(pci_mem_start);
+#endif
+
+/*
+ * This function checks if any part of the range <start,end> is mapped
+ * with type.
+ */
+int
+e820_any_mapped(u64 start, u64 end, unsigned type)
+{
+	int i;
+
+	for (i = 0; i < e820.nr_map; i++) {
+		struct e820entry *ei = &e820.map[i];
+
+		if (type && ei->type != type)
+			continue;
+		if (ei->addr >= end || ei->addr + ei->size <= start)
+			continue;
+		return 1;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(e820_any_mapped);
+
+/*
+ * This function checks if the entire range <start,end> is mapped with type.
+ *
+ * Note: this function only works correct if the e820 table is sorted and
+ * not-overlapping, which is the case
+ */
+int __init e820_all_mapped(u64 start, u64 end, unsigned type)
+{
+	int i;
+
+	for (i = 0; i < e820.nr_map; i++) {
+		struct e820entry *ei = &e820.map[i];
+
+		if (type && ei->type != type)
+			continue;
+		/* is the region (part) in overlap with the current region ?*/
+		if (ei->addr >= end || ei->addr + ei->size <= start)
+			continue;
+
+		/* if the region is at the beginning of <start,end> we move
+		 * start to the end of the region since it's ok until there
+		 */
+		if (ei->addr <= start)
+			start = ei->addr + ei->size;
+		/*
+		 * if start is now at or beyond end, we're done, full
+		 * coverage
+		 */
+		if (start >= end)
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Add a memory region to the kernel e820 map.
+ */
+static void __init __e820_add_region(struct e820map *e820x, u64 start, u64 size,
+					 int type)
+{
+	int x = e820x->nr_map;
+
+	if (x >= ARRAY_SIZE(e820x->map)) {
+		printk(KERN_ERR "e820: too many entries; ignoring [mem %#010llx-%#010llx]\n",
+		       (unsigned long long) start,
+		       (unsigned long long) (start + size - 1));
+		return;
+	}
+
+	e820x->map[x].addr = start;
+	e820x->map[x].size = size;
+	e820x->map[x].type = type;
+	e820x->nr_map++;
+}
+
+void __init e820_add_region(u64 start, u64 size, int type)
+{
+	__e820_add_region(&e820, start, size, type);
+}
+
+static void __init e820_print_type(u32 type)
+{
+	switch (type) {
+	case E820_RAM:
+	case E820_RESERVED_KERN:
+		printk(KERN_CONT "usable");
+		break;
+	case E820_RESERVED:
+		printk(KERN_CONT "reserved");
+		break;
+	case E820_ACPI:
+		printk(KERN_CONT "ACPI data");
+		break;
+	case E820_NVS:
+		printk(KERN_CONT "ACPI NVS");
+		break;
+	case E820_UNUSABLE:
+		printk(KERN_CONT "unusable");
+		break;
+	case E820_PRAM:
+		printk(KERN_CONT "persistent (type %u)", type);
+		break;
+	default:
+		printk(KERN_CONT "type %u", type);
+		break;
+	}
+}
+
+void __init e820_print_map(char *who)
+{
+	int i;
+
+	for (i = 0; i < e820.nr_map; i++) {
+		printk(KERN_INFO "%s: [mem %#018Lx-%#018Lx] ", who,
+		       (unsigned long long) e820.map[i].addr,
+		       (unsigned long long)
+		       (e820.map[i].addr + e820.map[i].size - 1));
+		e820_print_type(e820.map[i].type);
+		printk(KERN_CONT "\n");
+	}
+}
+
+/*
+ * Sanitize the BIOS e820 map.
+ *
+ * Some e820 responses include overlapping entries. The following
+ * replaces the original e820 map with a new one, removing overlaps,
+ * and resolving conflicting memory types in favor of highest
+ * numbered type.
+ *
+ * The input parameter biosmap points to an array of 'struct
+ * e820entry' which on entry has elements in the range [0, *pnr_map)
+ * valid, and which has space for up to max_nr_map entries.
+ * On return, the resulting sanitized e820 map entries will be in
+ * overwritten in the same location, starting at biosmap.
+ *
+ * The integer pointed to by pnr_map must be valid on entry (the
+ * current number of valid entries located at biosmap). If the
+ * sanitizing succeeds the *pnr_map will be updated with the new
+ * number of valid entries (something no more than max_nr_map).
+ *
+ * The return value from sanitize_e820_map() is zero if it
+ * successfully 'sanitized' the map entries passed in, and is -1
+ * if it did nothing, which can happen if either of (1) it was
+ * only passed one map entry, or (2) any of the input map entries
+ * were invalid (start + size < start, meaning that the size was
+ * so big the described memory range wrapped around through zero.)
+ *
+ *	Visually we're performing the following
+ *	(1,2,3,4 = memory types)...
+ *
+ *	Sample memory map (w/overlaps):
+ *	   ____22__________________
+ *	   ______________________4_
+ *	   ____1111________________
+ *	   _44_____________________
+ *	   11111111________________
+ *	   ____________________33__
+ *	   ___________44___________
+ *	   __________33333_________
+ *	   ______________22________
+ *	   ___________________2222_
+ *	   _________111111111______
+ *	   _____________________11_
+ *	   _________________4______
+ *
+ *	Sanitized equivalent (no overlap):
+ *	   1_______________________
+ *	   _44_____________________
+ *	   ___1____________________
+ *	   ____22__________________
+ *	   ______11________________
+ *	   _________1______________
+ *	   __________3_____________
+ *	   ___________44___________
+ *	   _____________33_________
+ *	   _______________2________
+ *	   ________________1_______
+ *	   _________________4______
+ *	   ___________________2____
+ *	   ____________________33__
+ *	   ______________________4_
+ */
+struct change_member {
+	struct e820entry *pbios; /* pointer to original bios entry */
+	unsigned long long addr; /* address for this change point */
+};
+
+static int __init cpcompare(const void *a, const void *b)
+{
+	struct change_member * const *app = a, * const *bpp = b;
+	const struct change_member *ap = *app, *bp = *bpp;
+
+	/*
+	 * Inputs are pointers to two elements of change_point[].  If their
+	 * addresses are unequal, their difference dominates.  If the addresses
+	 * are equal, then consider one that represents the end of its region
+	 * to be greater than one that does not.
+	 */
+	if (ap->addr != bp->addr)
+		return ap->addr > bp->addr ? 1 : -1;
+
+	return (ap->addr != ap->pbios->addr) - (bp->addr != bp->pbios->addr);
+}
+
+int __init sanitize_e820_map(struct e820entry *biosmap, int max_nr_map,
+			     u32 *pnr_map)
+{
+	static struct change_member change_point_list[2*E820_X_MAX] __initdata;
+	static struct change_member *change_point[2*E820_X_MAX] __initdata;
+	static struct e820entry *overlap_list[E820_X_MAX] __initdata;
+	static struct e820entry new_bios[E820_X_MAX] __initdata;
+	unsigned long current_type, last_type;
+	unsigned long long last_addr;
+	int chgidx;
+	int overlap_entries;
+	int new_bios_entry;
+	int old_nr, new_nr, chg_nr;
+	int i;
+
+	/* if there's only one memory region, don't bother */
+	if (*pnr_map < 2)
+		return -1;
+
+	old_nr = *pnr_map;
+	BUG_ON(old_nr > max_nr_map);
+
+	/* bail out if we find any unreasonable addresses in bios map */
+	for (i = 0; i < old_nr; i++)
+		if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr)
+			return -1;
+
+	/* create pointers for initial change-point information (for sorting) */
+	for (i = 0; i < 2 * old_nr; i++)
+		change_point[i] = &change_point_list[i];
+
+	/* record all known change-points (starting and ending addresses),
+	   omitting those that are for empty memory regions */
+	chgidx = 0;
+	for (i = 0; i < old_nr; i++)	{
+		if (biosmap[i].size != 0) {
+			change_point[chgidx]->addr = biosmap[i].addr;
+			change_point[chgidx++]->pbios = &biosmap[i];
+			change_point[chgidx]->addr = biosmap[i].addr +
+				biosmap[i].size;
+			change_point[chgidx++]->pbios = &biosmap[i];
+		}
+	}
+	chg_nr = chgidx;
+
+	/* sort change-point list by memory addresses (low -> high) */
+	sort(change_point, chg_nr, sizeof *change_point, cpcompare, NULL);
+
+	/* create a new bios memory map, removing overlaps */
+	overlap_entries = 0;	 /* number of entries in the overlap table */
+	new_bios_entry = 0;	 /* index for creating new bios map entries */
+	last_type = 0;		 /* start with undefined memory type */
+	last_addr = 0;		 /* start with 0 as last starting address */
+
+	/* loop through change-points, determining affect on the new bios map */
+	for (chgidx = 0; chgidx < chg_nr; chgidx++) {
+		/* keep track of all overlapping bios entries */
+		if (change_point[chgidx]->addr ==
+		    change_point[chgidx]->pbios->addr) {
+			/*
+			 * add map entry to overlap list (> 1 entry
+			 * implies an overlap)
+			 */
+			overlap_list[overlap_entries++] =
+				change_point[chgidx]->pbios;
+		} else {
+			/*
+			 * remove entry from list (order independent,
+			 * so swap with last)
+			 */
+			for (i = 0; i < overlap_entries; i++) {
+				if (overlap_list[i] ==
+				    change_point[chgidx]->pbios)
+					overlap_list[i] =
+						overlap_list[overlap_entries-1];
+			}
+			overlap_entries--;
+		}
+		/*
+		 * if there are overlapping entries, decide which
+		 * "type" to use (larger value takes precedence --
+		 * 1=usable, 2,3,4,4+=unusable)
+		 */
+		current_type = 0;
+		for (i = 0; i < overlap_entries; i++)
+			if (overlap_list[i]->type > current_type)
+				current_type = overlap_list[i]->type;
+		/*
+		 * continue building up new bios map based on this
+		 * information
+		 */
+		if (current_type != last_type || current_type == E820_PRAM) {
+			if (last_type != 0)	 {
+				new_bios[new_bios_entry].size =
+					change_point[chgidx]->addr - last_addr;
+				/*
+				 * move forward only if the new size
+				 * was non-zero
+				 */
+				if (new_bios[new_bios_entry].size != 0)
+					/*
+					 * no more space left for new
+					 * bios entries ?
+					 */
+					if (++new_bios_entry >= max_nr_map)
+						break;
+			}
+			if (current_type != 0)	{
+				new_bios[new_bios_entry].addr =
+					change_point[chgidx]->addr;
+				new_bios[new_bios_entry].type = current_type;
+				last_addr = change_point[chgidx]->addr;
+			}
+			last_type = current_type;
+		}
+	}
+	/* retain count for new bios entries */
+	new_nr = new_bios_entry;
+
+	/* copy new bios mapping into original location */
+	memcpy(biosmap, new_bios, new_nr * sizeof(struct e820entry));
+	*pnr_map = new_nr;
+
+	return 0;
+}
+
+static int __init __append_e820_map(struct e820entry *biosmap, int nr_map)
+{
+	while (nr_map) {
+		u64 start = biosmap->addr;
+		u64 size = biosmap->size;
+		u64 end = start + size;
+		u32 type = biosmap->type;
+
+		/* Overflow in 64 bits? Ignore the memory map. */
+		if (start > end)
+			return -1;
+
+		e820_add_region(start, size, type);
+
+		biosmap++;
+		nr_map--;
+	}
+	return 0;
+}
+
+/*
+ * Copy the BIOS e820 map into a safe place.
+ *
+ * Sanity-check it while we're at it..
+ *
+ * If we're lucky and live on a modern system, the setup code
+ * will have given us a memory map that we can use to properly
+ * set up memory.  If we aren't, we'll fake a memory map.
+ */
+static int __init append_e820_map(struct e820entry *biosmap, int nr_map)
+{
+	/* Only one memory region (or negative)? Ignore it */
+	if (nr_map < 2)
+		return -1;
+
+	return __append_e820_map(biosmap, nr_map);
+}
+
+static u64 __init __e820_update_range(struct e820map *e820x, u64 start,
+					u64 size, unsigned old_type,
+					unsigned new_type)
+{
+	u64 end;
+	unsigned int i;
+	u64 real_updated_size = 0;
+
+	BUG_ON(old_type == new_type);
+
+	if (size > (ULLONG_MAX - start))
+		size = ULLONG_MAX - start;
+
+	end = start + size;
+	printk(KERN_DEBUG "e820: update [mem %#010Lx-%#010Lx] ",
+	       (unsigned long long) start, (unsigned long long) (end - 1));
+	e820_print_type(old_type);
+	printk(KERN_CONT " ==> ");
+	e820_print_type(new_type);
+	printk(KERN_CONT "\n");
+
+	for (i = 0; i < e820x->nr_map; i++) {
+		struct e820entry *ei = &e820x->map[i];
+		u64 final_start, final_end;
+		u64 ei_end;
+
+		if (ei->type != old_type)
+			continue;
+
+		ei_end = ei->addr + ei->size;
+		/* totally covered by new range? */
+		if (ei->addr >= start && ei_end <= end) {
+			ei->type = new_type;
+			real_updated_size += ei->size;
+			continue;
+		}
+
+		/* new range is totally covered? */
+		if (ei->addr < start && ei_end > end) {
+			__e820_add_region(e820x, start, size, new_type);
+			__e820_add_region(e820x, end, ei_end - end, ei->type);
+			ei->size = start - ei->addr;
+			real_updated_size += size;
+			continue;
+		}
+
+		/* partially covered */
+		final_start = max(start, ei->addr);
+		final_end = min(end, ei_end);
+		if (final_start >= final_end)
+			continue;
+
+		__e820_add_region(e820x, final_start, final_end - final_start,
+				  new_type);
+
+		real_updated_size += final_end - final_start;
+
+		/*
+		 * left range could be head or tail, so need to update
+		 * size at first.
+		 */
+		ei->size -= final_end - final_start;
+		if (ei->addr < final_start)
+			continue;
+		ei->addr = final_end;
+	}
+	return real_updated_size;
+}
+
+u64 __init e820_update_range(u64 start, u64 size, unsigned old_type,
+			     unsigned new_type)
+{
+	return __e820_update_range(&e820, start, size, old_type, new_type);
+}
+
+static u64 __init e820_update_range_saved(u64 start, u64 size,
+					  unsigned old_type, unsigned new_type)
+{
+	return __e820_update_range(&e820_saved, start, size, old_type,
+				     new_type);
+}
+
+/* make e820 not cover the range */
+u64 __init e820_remove_range(u64 start, u64 size, unsigned old_type,
+			     int checktype)
+{
+	int i;
+	u64 end;
+	u64 real_removed_size = 0;
+
+	if (size > (ULLONG_MAX - start))
+		size = ULLONG_MAX - start;
+
+	end = start + size;
+	printk(KERN_DEBUG "e820: remove [mem %#010Lx-%#010Lx] ",
+	       (unsigned long long) start, (unsigned long long) (end - 1));
+	if (checktype)
+		e820_print_type(old_type);
+	printk(KERN_CONT "\n");
+
+	for (i = 0; i < e820.nr_map; i++) {
+		struct e820entry *ei = &e820.map[i];
+		u64 final_start, final_end;
+		u64 ei_end;
+
+		if (checktype && ei->type != old_type)
+			continue;
+
+		ei_end = ei->addr + ei->size;
+		/* totally covered? */
+		if (ei->addr >= start && ei_end <= end) {
+			real_removed_size += ei->size;
+			memset(ei, 0, sizeof(struct e820entry));
+			continue;
+		}
+
+		/* new range is totally covered? */
+		if (ei->addr < start && ei_end > end) {
+			e820_add_region(end, ei_end - end, ei->type);
+			ei->size = start - ei->addr;
+			real_removed_size += size;
+			continue;
+		}
+
+		/* partially covered */
+		final_start = max(start, ei->addr);
+		final_end = min(end, ei_end);
+		if (final_start >= final_end)
+			continue;
+		real_removed_size += final_end - final_start;
+
+		/*
+		 * left range could be head or tail, so need to update
+		 * size at first.
+		 */
+		ei->size -= final_end - final_start;
+		if (ei->addr < final_start)
+			continue;
+		ei->addr = final_end;
+	}
+	return real_removed_size;
+}
+
+void __init update_e820(void)
+{
+	if (sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map))
+		return;
+	printk(KERN_INFO "e820: modified physical RAM map:\n");
+	e820_print_map("modified");
+}
+static void __init update_e820_saved(void)
+{
+	sanitize_e820_map(e820_saved.map, ARRAY_SIZE(e820_saved.map),
+				&e820_saved.nr_map);
+}
+#define MAX_GAP_END 0x100000000ull
+/*
+ * Search for a gap in the e820 memory space from start_addr to end_addr.
+ */
+__init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
+		unsigned long start_addr, unsigned long long end_addr)
+{
+	unsigned long long last;
+	int i = e820.nr_map;
+	int found = 0;
+
+	last = (end_addr && end_addr < MAX_GAP_END) ? end_addr : MAX_GAP_END;
+
+	while (--i >= 0) {
+		unsigned long long start = e820.map[i].addr;
+		unsigned long long end = start + e820.map[i].size;
+
+		if (end < start_addr)
+			continue;
+
+		/*
+		 * Since "last" is at most 4GB, we know we'll
+		 * fit in 32 bits if this condition is true
+		 */
+		if (last > end) {
+			unsigned long gap = last - end;
+
+			if (gap >= *gapsize) {
+				*gapsize = gap;
+				*gapstart = end;
+				found = 1;
+			}
+		}
+		if (start < last)
+			last = start;
+	}
+	return found;
+}
+
+/*
+ * Search for the biggest gap in the low 32 bits of the e820
+ * memory space.  We pass this space to PCI to assign MMIO resources
+ * for hotplug or unconfigured devices in.
+ * Hopefully the BIOS let enough space left.
+ */
+__init void e820_setup_gap(void)
+{
+	unsigned long gapstart, gapsize;
+	int found;
+
+	gapstart = 0x10000000;
+	gapsize = 0x400000;
+	found  = e820_search_gap(&gapstart, &gapsize, 0, MAX_GAP_END);
+
+#ifdef CONFIG_X86_64
+	if (!found) {
+		gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
+		printk(KERN_ERR
+	"e820: cannot find a gap in the 32bit address range\n"
+	"e820: PCI devices with unassigned 32bit BARs may break!\n");
+	}
+#endif
+
+	/*
+	 * e820_reserve_resources_late protect stolen RAM already
+	 */
+	pci_mem_start = gapstart;
+
+	printk(KERN_INFO
+	       "e820: [mem %#010lx-%#010lx] available for PCI devices\n",
+	       gapstart, gapstart + gapsize - 1);
+}
+
+/**
+ * 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(u64 phys_addr, u32 data_len)
+{
+	int entries;
+	struct e820entry *extmap;
+	struct setup_data *sdata;
+
+	sdata = early_memremap(phys_addr, data_len);
+	entries = sdata->len / sizeof(struct e820entry);
+	extmap = (struct e820entry *)(sdata->data);
+	__append_e820_map(extmap, entries);
+	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+	early_memunmap(sdata, data_len);
+	printk(KERN_INFO "e820: extended physical RAM map:\n");
+	e820_print_map("extended");
+}
+
+#if defined(CONFIG_X86_64) || \
+	(defined(CONFIG_X86_32) && defined(CONFIG_HIBERNATION))
+/**
+ * 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.
+ */
+void __init e820_mark_nosave_regions(unsigned long limit_pfn)
+{
+	int i;
+	unsigned long pfn = 0;
+
+	for (i = 0; i < e820.nr_map; i++) {
+		struct e820entry *ei = &e820.map[i];
+
+		if (pfn < PFN_UP(ei->addr))
+			register_nosave_region(pfn, PFN_UP(ei->addr));
+
+		pfn = PFN_DOWN(ei->addr + ei->size);
+
+		if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
+			register_nosave_region(PFN_UP(ei->addr), pfn);
+
+		if (pfn >= limit_pfn)
+			break;
+	}
+}
+#endif
+
+#ifdef CONFIG_ACPI
+/**
+ * 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)
+			acpi_nvs_register(ei->addr, ei->size);
+	}
+
+	return 0;
+}
+core_initcall(e820_mark_nvs_memory);
+#endif
+
+/*
+ * pre allocated 4k and reserved it in memblock and e820_saved
+ */
+u64 __init early_reserve_e820(u64 size, u64 align)
+{
+	u64 addr;
+
+	addr = __memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
+	if (addr) {
+		e820_update_range_saved(addr, size, E820_RAM, E820_RESERVED);
+		printk(KERN_INFO "e820: update e820_saved for early_reserve_e820\n");
+		update_e820_saved();
+	}
+
+	return addr;
+}
+
+#ifdef CONFIG_X86_32
+# ifdef CONFIG_X86_PAE
+#  define MAX_ARCH_PFN		(1ULL<<(36-PAGE_SHIFT))
+# else
+#  define MAX_ARCH_PFN		(1ULL<<(32-PAGE_SHIFT))
+# endif
+#else /* CONFIG_X86_32 */
+# define MAX_ARCH_PFN MAXMEM>>PAGE_SHIFT
+#endif
+
+/*
+ * Find the highest page frame number we have available
+ */
+static unsigned long __init e820_end_pfn(unsigned long limit_pfn)
+{
+	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;
+
+		/*
+		 * Persistent memory is accounted as ram for purposes of
+		 * establishing max_pfn and mem_map.
+		 */
+		if (ei->type != E820_RAM && ei->type != E820_PRAM)
+			continue;
+
+		start_pfn = ei->addr >> PAGE_SHIFT;
+		end_pfn = (ei->addr + ei->size) >> PAGE_SHIFT;
+
+		if (start_pfn >= limit_pfn)
+			continue;
+		if (end_pfn > limit_pfn) {
+			last_pfn = limit_pfn;
+			break;
+		}
+		if (end_pfn > last_pfn)
+			last_pfn = end_pfn;
+	}
+
+	if (last_pfn > max_arch_pfn)
+		last_pfn = max_arch_pfn;
+
+	printk(KERN_INFO "e820: last_pfn = %#lx max_arch_pfn = %#lx\n",
+			 last_pfn, max_arch_pfn);
+	return last_pfn;
+}
+unsigned long __init e820_end_of_ram_pfn(void)
+{
+	return e820_end_pfn(MAX_ARCH_PFN);
+}
+
+unsigned long __init e820_end_of_low_ram_pfn(void)
+{
+	return e820_end_pfn(1UL << (32-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;
+
+	if (!strcmp(p, "nopentium")) {
+#ifdef CONFIG_X86_32
+		setup_clear_cpu_cap(X86_FEATURE_PSE);
+		return 0;
+#else
+		printk(KERN_WARNING "mem=nopentium ignored! (only supported on x86_32)\n");
+		return -EINVAL;
+#endif
+	}
+
+	userdef = 1;
+	mem_size = memparse(p, &p);
+	/* don't remove all of memory when handling "mem={invalid}" param */
+	if (mem_size == 0)
+		return -EINVAL;
+	e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);
+
+	return 0;
+}
+early_param("mem", parse_memopt);
+
+static int __init parse_memmap_one(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 if (*p == '!') {
+		start_at = memparse(p+1, &p);
+		e820_add_region(start_at, mem_size, E820_PRAM);
+	} else
+		e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);
+
+	return *p == '\0' ? 0 : -EINVAL;
+}
+static int __init parse_memmap_opt(char *str)
+{
+	while (str) {
+		char *k = strchr(str, ',');
+
+		if (k)
+			*k++ = 0;
+
+		parse_memmap_one(str);
+		str = k;
+	}
+
+	return 0;
+}
+early_param("memmap", parse_memmap_opt);
+
+void __init finish_e820_parsing(void)
+{
+	if (userdef) {
+		if (sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map),
+					&e820.nr_map) < 0)
+			early_panic("Invalid user supplied memory map");
+
+		printk(KERN_INFO "e820: user-defined physical RAM map:\n");
+		e820_print_map("user");
+	}
+}
+
+static inline const char *e820_type_to_string(int e820_type)
+{
+	switch (e820_type) {
+	case E820_RESERVED_KERN:
+	case E820_RAM:	return "System RAM";
+	case E820_ACPI:	return "ACPI Tables";
+	case E820_NVS:	return "ACPI Non-volatile Storage";
+	case E820_UNUSABLE:	return "Unusable memory";
+	case E820_PRAM: return "Persistent RAM";
+	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) &&
+		     (e820.map[i].type != E820_PRAM)) ||
+		     res->start < (1ULL<<20)) {
+			res->flags |= IORESOURCE_BUSY;
+			insert_resource(&iomem_resource, res);
+		}
+		res++;
+	}
+
+	for (i = 0; i < e820_saved.nr_map; i++) {
+		struct e820entry *entry = &e820_saved.map[i];
+		firmware_map_add_early(entry->addr,
+			entry->addr + entry->size,
+			e820_type_to_string(entry->type));
+	}
+}
+
+/* How much should we pad RAM ending depending on where it is? */
+static unsigned long ram_alignment(resource_size_t pos)
+{
+	unsigned long mb = pos >> 20;
+
+	/* To 64kB in the first megabyte */
+	if (!mb)
+		return 64*1024;
+
+	/* To 1MB in the first 16MB */
+	if (mb < 16)
+		return 1024*1024;
+
+	/* To 64MB for anything above that */
+	return 64*1024*1024;
+}
+
+#define MAX_RESOURCE_SIZE ((resource_size_t)-1)
+
+void __init e820_reserve_resources_late(void)
+{
+	int i;
+	struct resource *res;
+
+	res = e820_res;
+	for (i = 0; i < e820.nr_map; i++) {
+		if (!res->parent && res->end)
+			insert_resource_expand_to_fit(&iomem_resource, res);
+		res++;
+	}
+
+	/*
+	 * Try to bump up RAM regions to reasonable boundaries to
+	 * avoid stolen RAM:
+	 */
+	for (i = 0; i < e820.nr_map; i++) {
+		struct e820entry *entry = &e820.map[i];
+		u64 start, end;
+
+		if (entry->type != E820_RAM)
+			continue;
+		start = entry->addr + entry->size;
+		end = round_up(start, ram_alignment(start)) - 1;
+		if (end > MAX_RESOURCE_SIZE)
+			end = MAX_RESOURCE_SIZE;
+		if (start >= end)
+			continue;
+		printk(KERN_DEBUG
+		       "e820: reserve RAM buffer [mem %#010llx-%#010llx]\n",
+		       start, end);
+		reserve_region_with_split(&iomem_resource, start, end,
+					  "RAM buffer");
+	}
+}
+
+char *__init default_machine_specific_memory_setup(void)
+{
+	char *who = "BIOS-e820";
+	u32 new_nr;
+	/*
+	 * Try to copy the BIOS-supplied E820-map.
+	 *
+	 * Otherwise fake a memory map; one section from 0k->640k,
+	 * the next section from 1mb->appropriate_mem_k
+	 */
+	new_nr = boot_params.e820_entries;
+	sanitize_e820_map(boot_params.e820_map,
+			ARRAY_SIZE(boot_params.e820_map),
+			&new_nr);
+	boot_params.e820_entries = new_nr;
+	if (append_e820_map(boot_params.e820_map, boot_params.e820_entries)
+	  < 0) {
+		u64 mem_size;
+
+		/* compare results from other methods and take the greater */
+		if (boot_params.alt_mem_k
+		    < boot_params.screen_info.ext_mem_k) {
+			mem_size = boot_params.screen_info.ext_mem_k;
+			who = "BIOS-88";
+		} else {
+			mem_size = boot_params.alt_mem_k;
+			who = "BIOS-e801";
+		}
+
+		e820.nr_map = 0;
+		e820_add_region(0, LOWMEMSIZE(), E820_RAM);
+		e820_add_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
+	}
+
+	/* In case someone cares... */
+	return who;
+}
+
+void __init setup_memory_map(void)
+{
+	char *who;
+
+	who = x86_init.resources.memory_setup();
+	memcpy(&e820_saved, &e820, sizeof(struct e820map));
+	printk(KERN_INFO "e820: BIOS-provided physical RAM map:\n");
+	e820_print_map(who);
+}
+
+void __init memblock_x86_fill(void)
+{
+	int i;
+	u64 end;
+
+	/*
+	 * EFI may have more than 128 entries
+	 * We are safe to enable resizing, beause memblock_x86_fill()
+	 * is rather later for x86
+	 */
+	memblock_allow_resize();
+
+	for (i = 0; i < e820.nr_map; i++) {
+		struct e820entry *ei = &e820.map[i];
+
+		end = ei->addr + ei->size;
+		if (end != (resource_size_t)end)
+			continue;
+
+		if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
+			continue;
+
+		memblock_add(ei->addr, ei->size);
+	}
+
+	/* throw away partial pages */
+	memblock_trim_memory(PAGE_SIZE);
+
+	memblock_dump_all();
+}
+
+void __init memblock_find_dma_reserve(void)
+{
+#ifdef CONFIG_X86_64
+	u64 nr_pages = 0, nr_free_pages = 0;
+	unsigned long start_pfn, end_pfn;
+	phys_addr_t start, end;
+	int i;
+	u64 u;
+
+	/*
+	 * need to find out used area below MAX_DMA_PFN
+	 * need to use memblock to get free size in [0, MAX_DMA_PFN]
+	 * at first, and assume boot_mem will not take below MAX_DMA_PFN
+	 */
+	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
+		start_pfn = min(start_pfn, MAX_DMA_PFN);
+		end_pfn = min(end_pfn, MAX_DMA_PFN);
+		nr_pages += end_pfn - start_pfn;
+	}
+
+	for_each_free_mem_range(u, NUMA_NO_NODE, &start, &end, NULL) {
+		start_pfn = min_t(unsigned long, PFN_UP(start), MAX_DMA_PFN);
+		end_pfn = min_t(unsigned long, PFN_DOWN(end), MAX_DMA_PFN);
+		if (start_pfn < end_pfn)
+			nr_free_pages += end_pfn - start_pfn;
+	}
+
+	set_dma_reserve(nr_pages - nr_free_pages);
+#endif
+}