arch/x86/xen/setup.c - kernel/panda - Git at Google

 /*
  * Machine specific setup for xen
  *
  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
  */

 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/pm.h>
 #include <linux/memblock.h>
 #include <linux/cpuidle.h>

 #include <asm/elf.h>
 #include <asm/vdso.h>
 #include <asm/e820.h>
 #include <asm/setup.h>
 #include <asm/acpi.h>
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>

 #include <xen/xen.h>
 #include <xen/page.h>
 #include <xen/interface/callback.h>
 #include <xen/interface/memory.h>
 #include <xen/interface/physdev.h>
 #include <xen/features.h>

 #include "xen-ops.h"
 #include "vdso.h"

 /* These are code, but not functions.  Defined in entry.S */
 extern const char xen_hypervisor_callback[];
 extern const char xen_failsafe_callback[];
 extern void xen_sysenter_target(void);
 extern void xen_syscall_target(void);
 extern void xen_syscall32_target(void);

 /* Amount of extra memory space we add to the e820 ranges */
 struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;

 /* Number of pages released from the initial allocation. */
 unsigned long xen_released_pages;

 /*
  * The maximum amount of extra memory compared to the base size.  The
  * main scaling factor is the size of struct page.  At extreme ratios
  * of base:extra, all the base memory can be filled with page
  * structures for the extra memory, leaving no space for anything
  * else.
  *
  * 10x seems like a reasonable balance between scaling flexibility and
  * leaving a practically usable system.
  */
 #define EXTRA_MEM_RATIO		(10)

 static void __init xen_add_extra_mem(u64 start, u64 size)
 {
 	unsigned long pfn;
 	int i;

 	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
 		/* Add new region. */
 		if (xen_extra_mem[i].size == 0) {
 			xen_extra_mem[i].start = start;
 			xen_extra_mem[i].size  = size;
 			break;
 		}
 		/* Append to existing region. */
 		if (xen_extra_mem[i].start + xen_extra_mem[i].size == start) {
 			xen_extra_mem[i].size += size;
 			break;
 		}
 	}
 	if (i == XEN_EXTRA_MEM_MAX_REGIONS)
 		printk(KERN_WARNING "Warning: not enough extra memory regions\n");

 	memblock_x86_reserve_range(start, start + size, "XEN EXTRA");

 	xen_max_p2m_pfn = PFN_DOWN(start + size);

 	for (pfn = PFN_DOWN(start); pfn <= xen_max_p2m_pfn; pfn++)
 		__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
 }

 static unsigned long __init xen_release_chunk(unsigned long start,
 					      unsigned long end)
 {
 	struct xen_memory_reservation reservation = {
 		.address_bits = 0,
 		.extent_order = 0,
 		.domid        = DOMID_SELF
 	};
 	unsigned long len = 0;
 	unsigned long pfn;
 	int ret;

 	for(pfn = start; pfn < end; pfn++) {
 		unsigned long mfn = pfn_to_mfn(pfn);

 		/* Make sure pfn exists to start with */
 		if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
 			continue;

 		set_xen_guest_handle(reservation.extent_start, &mfn);
 		reservation.nr_extents = 1;

 		ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
 					   &reservation);
 		WARN(ret != 1, "Failed to release pfn %lx err=%d\n", pfn, ret);
 		if (ret == 1) {
 			__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
 			len++;
 		}
 	}
 	printk(KERN_INFO "Freeing  %lx-%lx pfn range: %lu pages freed\n",
 	       start, end, len);

 	return len;
 }

 static unsigned long __init xen_set_identity_and_release(
 	const struct e820entry *list, size_t map_size, unsigned long nr_pages)
 {
 	phys_addr_t start = 0;
 	unsigned long released = 0;
 	unsigned long identity = 0;
 	const struct e820entry *entry;
 	int i;

 	/*
 	 * Combine non-RAM regions and gaps until a RAM region (or the
 	 * end of the map) is reached, then set the 1:1 map and
 	 * release the pages (if available) in those non-RAM regions.
 	 *
 	 * The combined non-RAM regions are rounded to a whole number
 	 * of pages so any partial pages are accessible via the 1:1
 	 * mapping.  This is needed for some BIOSes that put (for
 	 * example) the DMI tables in a reserved region that begins on
 	 * a non-page boundary.
 	 */
 	for (i = 0, entry = list; i < map_size; i++, entry++) {
 		phys_addr_t end = entry->addr + entry->size;

 		if (entry->type == E820_RAM || i == map_size - 1) {
 			unsigned long start_pfn = PFN_DOWN(start);
 			unsigned long end_pfn = PFN_UP(end);

 			if (entry->type == E820_RAM)
 				end_pfn = PFN_UP(entry->addr);

 			if (start_pfn < end_pfn) {
 				if (start_pfn < nr_pages)
 					released += xen_release_chunk(
 						start_pfn, min(end_pfn, nr_pages));

 				identity += set_phys_range_identity(
 					start_pfn, end_pfn);
 			}
 			start = end;
 		}
 	}

 	printk(KERN_INFO "Released %lu pages of unused memory\n", released);
 	printk(KERN_INFO "Set %ld page(s) to 1-1 mapping\n", identity);

 	return released;
 }

 static unsigned long __init xen_get_max_pages(void)
 {
 	unsigned long max_pages = MAX_DOMAIN_PAGES;
 	domid_t domid = DOMID_SELF;
 	int ret;

 	/*
 	 * For the initial domain we use the maximum reservation as
 	 * the maximum page.
 	 *
 	 * For guest domains the current maximum reservation reflects
 	 * the current maximum rather than the static maximum. In this
 	 * case the e820 map provided to us will cover the static
 	 * maximum region.
 	 */
 	if (xen_initial_domain()) {
 		ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid);
 		if (ret > 0)
 			max_pages = ret;
 	}

 	return min(max_pages, MAX_DOMAIN_PAGES);
 }

 static void xen_align_and_add_e820_region(u64 start, u64 size, int type)
 {
 	u64 end = start + size;

 	/* Align RAM regions to page boundaries. */
 	if (type == E820_RAM) {
 		start = PAGE_ALIGN(start);
 		end &= ~((u64)PAGE_SIZE - 1);
 	}

 	e820_add_region(start, end - start, type);
 }

 /**
  * machine_specific_memory_setup - Hook for machine specific memory setup.
  **/
 char * __init xen_memory_setup(void)
 {
 	static struct e820entry map[E820MAX] __initdata;

 	unsigned long max_pfn = xen_start_info->nr_pages;
 	unsigned long long mem_end;
 	int rc;
 	struct xen_memory_map memmap;
 	unsigned long max_pages;
 	unsigned long extra_pages = 0;
 	int i;
 	int op;

 	max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
 	mem_end = PFN_PHYS(max_pfn);

 	memmap.nr_entries = E820MAX;
 	set_xen_guest_handle(memmap.buffer, map);

 	op = xen_initial_domain() ?
 		XENMEM_machine_memory_map :
 		XENMEM_memory_map;
 	rc = HYPERVISOR_memory_op(op, &memmap);
 	if (rc == -ENOSYS) {
 		BUG_ON(xen_initial_domain());
 		memmap.nr_entries = 1;
 		map[0].addr = 0ULL;
 		map[0].size = mem_end;
 		/* 8MB slack (to balance backend allocations). */
 		map[0].size += 8ULL << 20;
 		map[0].type = E820_RAM;
 		rc = 0;
 	}
 	BUG_ON(rc);

 	/* Make sure the Xen-supplied memory map is well-ordered. */
 	sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);

 	max_pages = xen_get_max_pages();
 	if (max_pages > max_pfn)
 		extra_pages += max_pages - max_pfn;

 	/*
 	 * Set P2M for all non-RAM pages and E820 gaps to be identity
 	 * type PFNs.  Any RAM pages that would be made inaccesible by
 	 * this are first released.
 	 */
 	xen_released_pages = xen_set_identity_and_release(
 		map, memmap.nr_entries, max_pfn);
 	extra_pages += xen_released_pages;

 	/*
 	 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
 	 * factor the base size.  On non-highmem systems, the base
 	 * size is the full initial memory allocation; on highmem it
 	 * is limited to the max size of lowmem, so that it doesn't
 	 * get completely filled.
 	 *
 	 * In principle there could be a problem in lowmem systems if
 	 * the initial memory is also very large with respect to
 	 * lowmem, but we won't try to deal with that here.
 	 */
 	extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
 			  extra_pages);

 	i = 0;
 	while (i < memmap.nr_entries) {
 		u64 addr = map[i].addr;
 		u64 size = map[i].size;
 		u32 type = map[i].type;

 		if (type == E820_RAM) {
 			if (addr < mem_end) {
 				size = min(size, mem_end - addr);
 			} else if (extra_pages) {
 				size = min(size, (u64)extra_pages * PAGE_SIZE);
 				extra_pages -= size / PAGE_SIZE;
 				xen_add_extra_mem(addr, size);
 			} else
 				type = E820_UNUSABLE;
 		}

 		xen_align_and_add_e820_region(addr, size, type);

 		map[i].addr += size;
 		map[i].size -= size;
 		if (map[i].size == 0)
 			i++;
 	}

 	/*
 	 * In domU, the ISA region is normal, usable memory, but we
 	 * reserve ISA memory anyway because too many things poke
 	 * about in there.
 	 */
 	e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
 			E820_RESERVED);

 	/*
 	 * Reserve Xen bits:
 	 *  - mfn_list
 	 *  - xen_start_info
 	 * See comment above "struct start_info" in <xen/interface/xen.h>
 	 */
 	memblock_x86_reserve_range(__pa(xen_start_info->mfn_list),
 		      __pa(xen_start_info->pt_base),
 			"XEN START INFO");

 	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

 	return "Xen";
 }

 /*
  * Set the bit indicating "nosegneg" library variants should be used.
  * We only need to bother in pure 32-bit mode; compat 32-bit processes
  * can have un-truncated segments, so wrapping around is allowed.
  */
 static void __init fiddle_vdso(void)
 {
 #ifdef CONFIG_X86_32
 	u32 *mask;
 	mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
 	*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
 	mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
 	*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
 #endif
 }

 static int __cpuinit register_callback(unsigned type, const void *func)
 {
 	struct callback_register callback = {
 		.type = type,
 		.address = XEN_CALLBACK(__KERNEL_CS, func),
 		.flags = CALLBACKF_mask_events,
 	};

 	return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
 }

 void __cpuinit xen_enable_sysenter(void)
 {
 	int ret;
 	unsigned sysenter_feature;

 #ifdef CONFIG_X86_32
 	sysenter_feature = X86_FEATURE_SEP;
 #else
 	sysenter_feature = X86_FEATURE_SYSENTER32;
 #endif

 	if (!boot_cpu_has(sysenter_feature))
 		return;

 	ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
 	if(ret != 0)
 		setup_clear_cpu_cap(sysenter_feature);
 }

 void __cpuinit xen_enable_syscall(void)
 {
 #ifdef CONFIG_X86_64
 	int ret;

 	ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
 	if (ret != 0) {
 		printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
 		/* Pretty fatal; 64-bit userspace has no other
 		   mechanism for syscalls. */
 	}

 	if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
 		ret = register_callback(CALLBACKTYPE_syscall32,
 					xen_syscall32_target);
 		if (ret != 0)
 			setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
 	}
 #endif /* CONFIG_X86_64 */
 }

 void __init xen_arch_setup(void)
 {
 	xen_panic_handler_init();

 	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
 	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);

 	if (!xen_feature(XENFEAT_auto_translated_physmap))
 		HYPERVISOR_vm_assist(VMASST_CMD_enable,
 				     VMASST_TYPE_pae_extended_cr3);

 	if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
 	    register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
 		BUG();

 	xen_enable_sysenter();
 	xen_enable_syscall();

 #ifdef CONFIG_ACPI
 	if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
 		printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
 		disable_acpi();
 	}
 #endif

 	memcpy(boot_command_line, xen_start_info->cmd_line,
 	       MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
 	       COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);

 	/* Set up idle, making sure it calls safe_halt() pvop */
 #ifdef CONFIG_X86_32
 	boot_cpu_data.hlt_works_ok = 1;
 #endif
 	disable_cpuidle();
 	boot_option_idle_override = IDLE_HALT;
 	WARN_ON(set_pm_idle_to_default());
 	fiddle_vdso();
 }
	/*
	* Machine specific setup for xen
	*
	* Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
	*/

	#include <linux/module.h>
	#include <linux/sched.h>
	#include <linux/mm.h>
	#include <linux/pm.h>
	#include <linux/memblock.h>
	#include <linux/cpuidle.h>

	#include <asm/elf.h>
	#include <asm/vdso.h>
	#include <asm/e820.h>
	#include <asm/setup.h>
	#include <asm/acpi.h>
	#include <asm/xen/hypervisor.h>
	#include <asm/xen/hypercall.h>

	#include <xen/xen.h>
	#include <xen/page.h>
	#include <xen/interface/callback.h>
	#include <xen/interface/memory.h>
	#include <xen/interface/physdev.h>
	#include <xen/features.h>

	#include "xen-ops.h"
	#include "vdso.h"

	/* These are code, but not functions. Defined in entry.S */
	extern const char xen_hypervisor_callback[];
	extern const char xen_failsafe_callback[];
	extern void xen_sysenter_target(void);
	extern void xen_syscall_target(void);
	extern void xen_syscall32_target(void);

	/* Amount of extra memory space we add to the e820 ranges */
	struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;

	/* Number of pages released from the initial allocation. */
	unsigned long xen_released_pages;

	/*
	* The maximum amount of extra memory compared to the base size. The
	* main scaling factor is the size of struct page. At extreme ratios
	* of base:extra, all the base memory can be filled with page
	* structures for the extra memory, leaving no space for anything
	* else.
	*
	* 10x seems like a reasonable balance between scaling flexibility and
	* leaving a practically usable system.
	*/
	#define EXTRA_MEM_RATIO (10)

	static void __init xen_add_extra_mem(u64 start, u64 size)
	{
	unsigned long pfn;
	int i;

	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
	/* Add new region. */
	if (xen_extra_mem[i].size == 0) {
	xen_extra_mem[i].start = start;
	xen_extra_mem[i].size = size;
	break;
	}
	/* Append to existing region. */
	if (xen_extra_mem[i].start + xen_extra_mem[i].size == start) {
	xen_extra_mem[i].size += size;
	break;
	}
	}
	if (i == XEN_EXTRA_MEM_MAX_REGIONS)
	printk(KERN_WARNING "Warning: not enough extra memory regions\n");

	memblock_x86_reserve_range(start, start + size, "XEN EXTRA");

	xen_max_p2m_pfn = PFN_DOWN(start + size);

	for (pfn = PFN_DOWN(start); pfn <= xen_max_p2m_pfn; pfn++)
	__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
	}

	static unsigned long __init xen_release_chunk(unsigned long start,
	unsigned long end)
	{
	struct xen_memory_reservation reservation = {
	.address_bits = 0,
	.extent_order = 0,
	.domid = DOMID_SELF
	};
	unsigned long len = 0;
	unsigned long pfn;
	int ret;

	for(pfn = start; pfn < end; pfn++) {
	unsigned long mfn = pfn_to_mfn(pfn);

	/* Make sure pfn exists to start with */
	if (mfn == INVALID_P2M_ENTRY \|\| mfn_to_pfn(mfn) != pfn)
	continue;

	set_xen_guest_handle(reservation.extent_start, &mfn);
	reservation.nr_extents = 1;

	ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
	&reservation);
	WARN(ret != 1, "Failed to release pfn %lx err=%d\n", pfn, ret);
	if (ret == 1) {
	__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
	len++;
	}
	}
	printk(KERN_INFO "Freeing %lx-%lx pfn range: %lu pages freed\n",
	start, end, len);

	return len;
	}

	static unsigned long __init xen_set_identity_and_release(
	const struct e820entry *list, size_t map_size, unsigned long nr_pages)
	{
	phys_addr_t start = 0;
	unsigned long released = 0;
	unsigned long identity = 0;
	const struct e820entry *entry;
	int i;

	/*
	* Combine non-RAM regions and gaps until a RAM region (or the
	* end of the map) is reached, then set the 1:1 map and
	* release the pages (if available) in those non-RAM regions.
	*
	* The combined non-RAM regions are rounded to a whole number
	* of pages so any partial pages are accessible via the 1:1
	* mapping. This is needed for some BIOSes that put (for
	* example) the DMI tables in a reserved region that begins on
	* a non-page boundary.
	*/
	for (i = 0, entry = list; i < map_size; i++, entry++) {
	phys_addr_t end = entry->addr + entry->size;

	if (entry->type == E820_RAM \|\| i == map_size - 1) {
	unsigned long start_pfn = PFN_DOWN(start);
	unsigned long end_pfn = PFN_UP(end);

	if (entry->type == E820_RAM)
	end_pfn = PFN_UP(entry->addr);

	if (start_pfn < end_pfn) {
	if (start_pfn < nr_pages)
	released += xen_release_chunk(
	start_pfn, min(end_pfn, nr_pages));

	identity += set_phys_range_identity(
	start_pfn, end_pfn);
	}
	start = end;
	}
	}

	printk(KERN_INFO "Released %lu pages of unused memory\n", released);
	printk(KERN_INFO "Set %ld page(s) to 1-1 mapping\n", identity);

	return released;
	}

	static unsigned long __init xen_get_max_pages(void)
	{
	unsigned long max_pages = MAX_DOMAIN_PAGES;
	domid_t domid = DOMID_SELF;
	int ret;

	/*
	* For the initial domain we use the maximum reservation as
	* the maximum page.
	*
	* For guest domains the current maximum reservation reflects
	* the current maximum rather than the static maximum. In this
	* case the e820 map provided to us will cover the static
	* maximum region.
	*/
	if (xen_initial_domain()) {
	ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid);
	if (ret > 0)
	max_pages = ret;
	}

	return min(max_pages, MAX_DOMAIN_PAGES);
	}

	static void xen_align_and_add_e820_region(u64 start, u64 size, int type)
	{
	u64 end = start + size;

	/* Align RAM regions to page boundaries. */
	if (type == E820_RAM) {
	start = PAGE_ALIGN(start);
	end &= ~((u64)PAGE_SIZE - 1);
	}

	e820_add_region(start, end - start, type);
	}

	/**
	* machine_specific_memory_setup - Hook for machine specific memory setup.
	**/
	char * __init xen_memory_setup(void)
	{
	static struct e820entry map[E820MAX] __initdata;

	unsigned long max_pfn = xen_start_info->nr_pages;
	unsigned long long mem_end;
	int rc;
	struct xen_memory_map memmap;
	unsigned long max_pages;
	unsigned long extra_pages = 0;
	int i;
	int op;

	max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
	mem_end = PFN_PHYS(max_pfn);

	memmap.nr_entries = E820MAX;
	set_xen_guest_handle(memmap.buffer, map);

	op = xen_initial_domain() ?
	XENMEM_machine_memory_map :
	XENMEM_memory_map;
	rc = HYPERVISOR_memory_op(op, &memmap);
	if (rc == -ENOSYS) {
	BUG_ON(xen_initial_domain());
	memmap.nr_entries = 1;
	map[0].addr = 0ULL;
	map[0].size = mem_end;
	/* 8MB slack (to balance backend allocations). */
	map[0].size += 8ULL << 20;
	map[0].type = E820_RAM;
	rc = 0;
	}
	BUG_ON(rc);

	/* Make sure the Xen-supplied memory map is well-ordered. */
	sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);

	max_pages = xen_get_max_pages();
	if (max_pages > max_pfn)
	extra_pages += max_pages - max_pfn;

	/*
	* Set P2M for all non-RAM pages and E820 gaps to be identity
	* type PFNs. Any RAM pages that would be made inaccesible by
	* this are first released.
	*/
	xen_released_pages = xen_set_identity_and_release(
	map, memmap.nr_entries, max_pfn);
	extra_pages += xen_released_pages;

	/*
	* Clamp the amount of extra memory to a EXTRA_MEM_RATIO
	* factor the base size. On non-highmem systems, the base
	* size is the full initial memory allocation; on highmem it
	* is limited to the max size of lowmem, so that it doesn't
	* get completely filled.
	*
	* In principle there could be a problem in lowmem systems if
	* the initial memory is also very large with respect to
	* lowmem, but we won't try to deal with that here.
	*/
	extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
	extra_pages);

	i = 0;
	while (i < memmap.nr_entries) {
	u64 addr = map[i].addr;
	u64 size = map[i].size;
	u32 type = map[i].type;

	if (type == E820_RAM) {
	if (addr < mem_end) {
	size = min(size, mem_end - addr);
	} else if (extra_pages) {
	size = min(size, (u64)extra_pages * PAGE_SIZE);
	extra_pages -= size / PAGE_SIZE;
	xen_add_extra_mem(addr, size);
	} else
	type = E820_UNUSABLE;
	}

	xen_align_and_add_e820_region(addr, size, type);

	map[i].addr += size;
	map[i].size -= size;
	if (map[i].size == 0)
	i++;
	}

	/*
	* In domU, the ISA region is normal, usable memory, but we
	* reserve ISA memory anyway because too many things poke
	* about in there.
	*/
	e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
	E820_RESERVED);

	/*
	* Reserve Xen bits:
	* - mfn_list
	* - xen_start_info
	* See comment above "struct start_info" in <xen/interface/xen.h>
	*/
	memblock_x86_reserve_range(__pa(xen_start_info->mfn_list),
	__pa(xen_start_info->pt_base),
	"XEN START INFO");

	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

	return "Xen";
	}

	/*
	* Set the bit indicating "nosegneg" library variants should be used.
	* We only need to bother in pure 32-bit mode; compat 32-bit processes
	* can have un-truncated segments, so wrapping around is allowed.
	*/
	static void __init fiddle_vdso(void)
	{
	#ifdef CONFIG_X86_32
	u32 *mask;
	mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
	*mask \|= 1 << VDSO_NOTE_NONEGSEG_BIT;
	mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
	*mask \|= 1 << VDSO_NOTE_NONEGSEG_BIT;
	#endif
	}

	static int __cpuinit register_callback(unsigned type, const void *func)
	{
	struct callback_register callback = {
	.type = type,
	.address = XEN_CALLBACK(__KERNEL_CS, func),
	.flags = CALLBACKF_mask_events,
	};

	return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
	}

	void __cpuinit xen_enable_sysenter(void)
	{
	int ret;
	unsigned sysenter_feature;

	#ifdef CONFIG_X86_32
	sysenter_feature = X86_FEATURE_SEP;
	#else
	sysenter_feature = X86_FEATURE_SYSENTER32;
	#endif

	if (!boot_cpu_has(sysenter_feature))
	return;

	ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
	if(ret != 0)
	setup_clear_cpu_cap(sysenter_feature);
	}

	void __cpuinit xen_enable_syscall(void)
	{
	#ifdef CONFIG_X86_64
	int ret;

	ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
	if (ret != 0) {
	printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
	/* Pretty fatal; 64-bit userspace has no other
	mechanism for syscalls. */
	}

	if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
	ret = register_callback(CALLBACKTYPE_syscall32,
	xen_syscall32_target);
	if (ret != 0)
	setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
	}
	#endif /* CONFIG_X86_64 */
	}

	void __init xen_arch_setup(void)
	{
	xen_panic_handler_init();

	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);

	if (!xen_feature(XENFEAT_auto_translated_physmap))
	HYPERVISOR_vm_assist(VMASST_CMD_enable,
	VMASST_TYPE_pae_extended_cr3);

	if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) \|\|
	register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
	BUG();

	xen_enable_sysenter();
	xen_enable_syscall();

	#ifdef CONFIG_ACPI
	if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
	printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
	disable_acpi();
	}
	#endif

	memcpy(boot_command_line, xen_start_info->cmd_line,
	MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
	COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);

	/* Set up idle, making sure it calls safe_halt() pvop */
	#ifdef CONFIG_X86_32
	boot_cpu_data.hlt_works_ok = 1;
	#endif
	disable_cpuidle();
	boot_option_idle_override = IDLE_HALT;
	WARN_ON(set_pm_idle_to_default());
	fiddle_vdso();
	}