Initial import

5 files changed, 1493 insertions, 0 deletions

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
new file mode 100644
index 000000000..280bc0a63
--- /dev/null
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -0,0 +1,41 @@
+#
+# The stub may be linked into the kernel proper or into a separate boot binary,
+# but in either case, it executes before the kernel does (with MMU disabled) so
+# things like ftrace and stack-protector are likely to cause trouble if left
+# enabled, even if doing so doesn't break the build.
+#
+cflags-$(CONFIG_X86_32)		:= -march=i386
+cflags-$(CONFIG_X86_64)		:= -mcmodel=small
+cflags-$(CONFIG_X86)		+= -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2 \
+				   -fPIC -fno-strict-aliasing -mno-red-zone \
+				   -mno-mmx -mno-sse -DDISABLE_BRANCH_PROFILING
+
+cflags-$(CONFIG_ARM64)		:= $(subst -pg,,$(KBUILD_CFLAGS))
+cflags-$(CONFIG_ARM)		:= $(subst -pg,,$(KBUILD_CFLAGS)) \
+				   -fno-builtin -fpic -mno-single-pic-base
+
+KBUILD_CFLAGS			:= $(cflags-y) \
+				   $(call cc-option,-ffreestanding) \
+				   $(call cc-option,-fno-stack-protector)
+
+GCOV_PROFILE			:= n
+KASAN_SANITIZE			:= n
+
+lib-y				:= efi-stub-helper.o
+lib-$(CONFIG_EFI_ARMSTUB)	+= arm-stub.o fdt.o
+
+CFLAGS_fdt.o			+= -I$(srctree)/scripts/dtc/libfdt/
+
+#
+# arm64 puts the stub in the kernel proper, which will unnecessarily retain all
+# code indefinitely unless it is annotated as __init/__initdata/__initconst etc.
+# So let's apply the __init annotations at the section level, by prefixing
+# the section names directly. This will ensure that even all the inline string
+# literals are covered.
+#
+extra-$(CONFIG_ARM64)		:= $(lib-y)
+lib-$(CONFIG_ARM64)		:= $(patsubst %.o,%.init.o,$(lib-y))
+
+OBJCOPYFLAGS := --prefix-alloc-sections=.init
+$(obj)/%.init.o: $(obj)/%.o FORCE
+	$(call if_changed,objcopy)
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
new file mode 100644
index 000000000..e29560e6b
--- /dev/null
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -0,0 +1,355 @@
+/*
+ * EFI stub implementation that is shared by arm and arm64 architectures.
+ * This should be #included by the EFI stub implementation files.
+ *
+ * Copyright (C) 2013,2014 Linaro Limited
+ *     Roy Franz <roy.franz@linaro.org
+ * Copyright (C) 2013 Red Hat, Inc.
+ *     Mark Salter <msalter@redhat.com>
+ *
+ * This file is part of the Linux kernel, and is made available under the
+ * terms of the GNU General Public License version 2.
+ *
+ */
+
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+static int efi_secureboot_enabled(efi_system_table_t *sys_table_arg)
+{
+	static efi_guid_t const var_guid = EFI_GLOBAL_VARIABLE_GUID;
+	static efi_char16_t const var_name[] = {
+		'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
+
+	efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
+	unsigned long size = sizeof(u8);
+	efi_status_t status;
+	u8 val;
+
+	status = f_getvar((efi_char16_t *)var_name, (efi_guid_t *)&var_guid,
+			  NULL, &size, &val);
+
+	switch (status) {
+	case EFI_SUCCESS:
+		return val;
+	case EFI_NOT_FOUND:
+		return 0;
+	default:
+		return 1;
+	}
+}
+
+efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
+			     void *__image, void **__fh)
+{
+	efi_file_io_interface_t *io;
+	efi_loaded_image_t *image = __image;
+	efi_file_handle_t *fh;
+	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
+	efi_status_t status;
+	void *handle = (void *)(unsigned long)image->device_handle;
+
+	status = sys_table_arg->boottime->handle_protocol(handle,
+				 &fs_proto, (void **)&io);
+	if (status != EFI_SUCCESS) {
+		efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
+		return status;
+	}
+
+	status = io->open_volume(io, &fh);
+	if (status != EFI_SUCCESS)
+		efi_printk(sys_table_arg, "Failed to open volume\n");
+
+	*__fh = fh;
+	return status;
+}
+
+efi_status_t efi_file_close(void *handle)
+{
+	efi_file_handle_t *fh = handle;
+
+	return fh->close(handle);
+}
+
+efi_status_t
+efi_file_read(void *handle, unsigned long *size, void *addr)
+{
+	efi_file_handle_t *fh = handle;
+
+	return fh->read(handle, size, addr);
+}
+
+
+efi_status_t
+efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
+	      efi_char16_t *filename_16, void **handle, u64 *file_sz)
+{
+	efi_file_handle_t *h, *fh = __fh;
+	efi_file_info_t *info;
+	efi_status_t status;
+	efi_guid_t info_guid = EFI_FILE_INFO_ID;
+	unsigned long info_sz;
+
+	status = fh->open(fh, &h, filename_16, EFI_FILE_MODE_READ, (u64)0);
+	if (status != EFI_SUCCESS) {
+		efi_printk(sys_table_arg, "Failed to open file: ");
+		efi_char16_printk(sys_table_arg, filename_16);
+		efi_printk(sys_table_arg, "\n");
+		return status;
+	}
+
+	*handle = h;
+
+	info_sz = 0;
+	status = h->get_info(h, &info_guid, &info_sz, NULL);
+	if (status != EFI_BUFFER_TOO_SMALL) {
+		efi_printk(sys_table_arg, "Failed to get file info size\n");
+		return status;
+	}
+
+grow:
+	status = sys_table_arg->boottime->allocate_pool(EFI_LOADER_DATA,
+				 info_sz, (void **)&info);
+	if (status != EFI_SUCCESS) {
+		efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
+		return status;
+	}
+
+	status = h->get_info(h, &info_guid, &info_sz,
+						   info);
+	if (status == EFI_BUFFER_TOO_SMALL) {
+		sys_table_arg->boottime->free_pool(info);
+		goto grow;
+	}
+
+	*file_sz = info->file_size;
+	sys_table_arg->boottime->free_pool(info);
+
+	if (status != EFI_SUCCESS)
+		efi_printk(sys_table_arg, "Failed to get initrd info\n");
+
+	return status;
+}
+
+
+
+void efi_char16_printk(efi_system_table_t *sys_table_arg,
+			      efi_char16_t *str)
+{
+	struct efi_simple_text_output_protocol *out;
+
+	out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
+	out->output_string(out, str);
+}
+
+
+/*
+ * This function handles the architcture specific differences between arm and
+ * arm64 regarding where the kernel image must be loaded and any memory that
+ * must be reserved. On failure it is required to free all
+ * all allocations it has made.
+ */
+efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
+				 unsigned long *image_addr,
+				 unsigned long *image_size,
+				 unsigned long *reserve_addr,
+				 unsigned long *reserve_size,
+				 unsigned long dram_base,
+				 efi_loaded_image_t *image);
+/*
+ * EFI entry point for the arm/arm64 EFI stubs.  This is the entrypoint
+ * that is described in the PE/COFF header.  Most of the code is the same
+ * for both archictectures, with the arch-specific code provided in the
+ * handle_kernel_image() function.
+ */
+unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
+			       unsigned long *image_addr)
+{
+	efi_loaded_image_t *image;
+	efi_status_t status;
+	unsigned long image_size = 0;
+	unsigned long dram_base;
+	/* addr/point and size pairs for memory management*/
+	unsigned long initrd_addr;
+	u64 initrd_size = 0;
+	unsigned long fdt_addr = 0;  /* Original DTB */
+	unsigned long fdt_size = 0;
+	char *cmdline_ptr = NULL;
+	int cmdline_size = 0;
+	unsigned long new_fdt_addr;
+	efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
+	unsigned long reserve_addr = 0;
+	unsigned long reserve_size = 0;
+
+	/* Check if we were booted by the EFI firmware */
+	if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
+		goto fail;
+
+	pr_efi(sys_table, "Booting Linux Kernel...\n");
+
+	/*
+	 * Get a handle to the loaded image protocol.  This is used to get
+	 * information about the running image, such as size and the command
+	 * line.
+	 */
+	status = sys_table->boottime->handle_protocol(handle,
+					&loaded_image_proto, (void *)&image);
+	if (status != EFI_SUCCESS) {
+		pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
+		goto fail;
+	}
+
+	dram_base = get_dram_base(sys_table);
+	if (dram_base == EFI_ERROR) {
+		pr_efi_err(sys_table, "Failed to find DRAM base\n");
+		goto fail;
+	}
+	status = handle_kernel_image(sys_table, image_addr, &image_size,
+				     &reserve_addr,
+				     &reserve_size,
+				     dram_base, image);
+	if (status != EFI_SUCCESS) {
+		pr_efi_err(sys_table, "Failed to relocate kernel\n");
+		goto fail;
+	}
+
+	/*
+	 * Get the command line from EFI, using the LOADED_IMAGE
+	 * protocol. We are going to copy the command line into the
+	 * device tree, so this can be allocated anywhere.
+	 */
+	cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
+	if (!cmdline_ptr) {
+		pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
+		goto fail_free_image;
+	}
+
+	status = efi_parse_options(cmdline_ptr);
+	if (status != EFI_SUCCESS)
+		pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n");
+
+	/*
+	 * Unauthenticated device tree data is a security hazard, so
+	 * ignore 'dtb=' unless UEFI Secure Boot is disabled.
+	 */
+	if (efi_secureboot_enabled(sys_table)) {
+		pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
+	} else {
+		status = handle_cmdline_files(sys_table, image, cmdline_ptr,
+					      "dtb=",
+					      ~0UL, &fdt_addr, &fdt_size);
+
+		if (status != EFI_SUCCESS) {
+			pr_efi_err(sys_table, "Failed to load device tree!\n");
+			goto fail_free_cmdline;
+		}
+	}
+
+	if (fdt_addr) {
+		pr_efi(sys_table, "Using DTB from command line\n");
+	} else {
+		/* Look for a device tree configuration table entry. */
+		fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
+		if (fdt_addr)
+			pr_efi(sys_table, "Using DTB from configuration table\n");
+	}
+
+	if (!fdt_addr)
+		pr_efi(sys_table, "Generating empty DTB\n");
+
+	status = handle_cmdline_files(sys_table, image, cmdline_ptr,
+				      "initrd=", dram_base + SZ_512M,
+				      (unsigned long *)&initrd_addr,
+				      (unsigned long *)&initrd_size);
+	if (status != EFI_SUCCESS)
+		pr_efi_err(sys_table, "Failed initrd from command line!\n");
+
+	new_fdt_addr = fdt_addr;
+	status = allocate_new_fdt_and_exit_boot(sys_table, handle,
+				&new_fdt_addr, dram_base + MAX_FDT_OFFSET,
+				initrd_addr, initrd_size, cmdline_ptr,
+				fdt_addr, fdt_size);
+
+	/*
+	 * If all went well, we need to return the FDT address to the
+	 * calling function so it can be passed to kernel as part of
+	 * the kernel boot protocol.
+	 */
+	if (status == EFI_SUCCESS)
+		return new_fdt_addr;
+
+	pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
+
+	efi_free(sys_table, initrd_size, initrd_addr);
+	efi_free(sys_table, fdt_size, fdt_addr);
+
+fail_free_cmdline:
+	efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
+
+fail_free_image:
+	efi_free(sys_table, image_size, *image_addr);
+	efi_free(sys_table, reserve_size, reserve_addr);
+fail:
+	return EFI_ERROR;
+}
+
+/*
+ * This is the base address at which to start allocating virtual memory ranges
+ * for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
+ * any allocation we choose, and eliminate the risk of a conflict after kexec.
+ * The value chosen is the largest non-zero power of 2 suitable for this purpose
+ * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
+ * be mapped efficiently.
+ */
+#define EFI_RT_VIRTUAL_BASE	0x40000000
+
+/*
+ * efi_get_virtmap() - create a virtual mapping for the EFI memory map
+ *
+ * This function populates the virt_addr fields of all memory region descriptors
+ * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
+ * are also copied to @runtime_map, and their total count is returned in @count.
+ */
+void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
+		     unsigned long desc_size, efi_memory_desc_t *runtime_map,
+		     int *count)
+{
+	u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
+	efi_memory_desc_t *out = runtime_map;
+	int l;
+
+	for (l = 0; l < map_size; l += desc_size) {
+		efi_memory_desc_t *in = (void *)memory_map + l;
+		u64 paddr, size;
+
+		if (!(in->attribute & EFI_MEMORY_RUNTIME))
+			continue;
+
+		/*
+		 * Make the mapping compatible with 64k pages: this allows
+		 * a 4k page size kernel to kexec a 64k page size kernel and
+		 * vice versa.
+		 */
+		paddr = round_down(in->phys_addr, SZ_64K);
+		size = round_up(in->num_pages * EFI_PAGE_SIZE +
+				in->phys_addr - paddr, SZ_64K);
+
+		/*
+		 * Avoid wasting memory on PTEs by choosing a virtual base that
+		 * is compatible with section mappings if this region has the
+		 * appropriate size and physical alignment. (Sections are 2 MB
+		 * on 4k granule kernels)
+		 */
+		if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
+			efi_virt_base = round_up(efi_virt_base, SZ_2M);
+
+		in->virt_addr = efi_virt_base + in->phys_addr - paddr;
+		efi_virt_base += size;
+
+		memcpy(out, in, desc_size);
+		out = (void *)out + desc_size;
+		++*count;
+	}
+}
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
new file mode 100644
index 000000000..f07d4a67f
--- /dev/null
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -0,0 +1,699 @@
+/*
+ * Helper functions used by the EFI stub on multiple
+ * architectures. This should be #included by the EFI stub
+ * implementation files.
+ *
+ * Copyright 2011 Intel Corporation; author Matt Fleming
+ *
+ * This file is part of the Linux kernel, and is made available
+ * under the terms of the GNU General Public License version 2.
+ *
+ */
+
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+/*
+ * Some firmware implementations have problems reading files in one go.
+ * A read chunk size of 1MB seems to work for most platforms.
+ *
+ * Unfortunately, reading files in chunks triggers *other* bugs on some
+ * platforms, so we provide a way to disable this workaround, which can
+ * be done by passing "efi=nochunk" on the EFI boot stub command line.
+ *
+ * If you experience issues with initrd images being corrupt it's worth
+ * trying efi=nochunk, but chunking is enabled by default because there
+ * are far more machines that require the workaround than those that
+ * break with it enabled.
+ */
+#define EFI_READ_CHUNK_SIZE	(1024 * 1024)
+
+static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;
+
+/*
+ * Allow the platform to override the allocation granularity: this allows
+ * systems that have the capability to run with a larger page size to deal
+ * with the allocations for initrd and fdt more efficiently.
+ */
+#ifndef EFI_ALLOC_ALIGN
+#define EFI_ALLOC_ALIGN		EFI_PAGE_SIZE
+#endif
+
+struct file_info {
+	efi_file_handle_t *handle;
+	u64 size;
+};
+
+void efi_printk(efi_system_table_t *sys_table_arg, char *str)
+{
+	char *s8;
+
+	for (s8 = str; *s8; s8++) {
+		efi_char16_t ch[2] = { 0 };
+
+		ch[0] = *s8;
+		if (*s8 == '\n') {
+			efi_char16_t nl[2] = { '\r', 0 };
+			efi_char16_printk(sys_table_arg, nl);
+		}
+
+		efi_char16_printk(sys_table_arg, ch);
+	}
+}
+
+efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
+				efi_memory_desc_t **map,
+				unsigned long *map_size,
+				unsigned long *desc_size,
+				u32 *desc_ver,
+				unsigned long *key_ptr)
+{
+	efi_memory_desc_t *m = NULL;
+	efi_status_t status;
+	unsigned long key;
+	u32 desc_version;
+
+	*map_size = sizeof(*m) * 32;
+again:
+	/*
+	 * Add an additional efi_memory_desc_t because we're doing an
+	 * allocation which may be in a new descriptor region.
+	 */
+	*map_size += sizeof(*m);
+	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
+				*map_size, (void **)&m);
+	if (status != EFI_SUCCESS)
+		goto fail;
+
+	*desc_size = 0;
+	key = 0;
+	status = efi_call_early(get_memory_map, map_size, m,
+				&key, desc_size, &desc_version);
+	if (status == EFI_BUFFER_TOO_SMALL) {
+		efi_call_early(free_pool, m);
+		goto again;
+	}
+
+	if (status != EFI_SUCCESS)
+		efi_call_early(free_pool, m);
+
+	if (key_ptr && status == EFI_SUCCESS)
+		*key_ptr = key;
+	if (desc_ver && status == EFI_SUCCESS)
+		*desc_ver = desc_version;
+
+fail:
+	*map = m;
+	return status;
+}
+
+
+unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
+{
+	efi_status_t status;
+	unsigned long map_size;
+	unsigned long membase  = EFI_ERROR;
+	struct efi_memory_map map;
+	efi_memory_desc_t *md;
+
+	status = efi_get_memory_map(sys_table_arg, (efi_memory_desc_t **)&map.map,
+				    &map_size, &map.desc_size, NULL, NULL);
+	if (status != EFI_SUCCESS)
+		return membase;
+
+	map.map_end = map.map + map_size;
+
+	for_each_efi_memory_desc(&map, md)
+		if (md->attribute & EFI_MEMORY_WB)
+			if (membase > md->phys_addr)
+				membase = md->phys_addr;
+
+	efi_call_early(free_pool, map.map);
+
+	return membase;
+}
+
+/*
+ * Allocate at the highest possible address that is not above 'max'.
+ */
+efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
+			    unsigned long size, unsigned long align,
+			    unsigned long *addr, unsigned long max)
+{
+	unsigned long map_size, desc_size;
+	efi_memory_desc_t *map;
+	efi_status_t status;
+	unsigned long nr_pages;
+	u64 max_addr = 0;
+	int i;
+
+	status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
+				    NULL, NULL);
+	if (status != EFI_SUCCESS)
+		goto fail;
+
+	/*
+	 * Enforce minimum alignment that EFI requires when requesting
+	 * a specific address.  We are doing page-based allocations,
+	 * so we must be aligned to a page.
+	 */
+	if (align < EFI_ALLOC_ALIGN)
+		align = EFI_ALLOC_ALIGN;
+
+	nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
+again:
+	for (i = 0; i < map_size / desc_size; i++) {
+		efi_memory_desc_t *desc;
+		unsigned long m = (unsigned long)map;
+		u64 start, end;
+
+		desc = (efi_memory_desc_t *)(m + (i * desc_size));
+		if (desc->type != EFI_CONVENTIONAL_MEMORY)
+			continue;
+
+		if (desc->num_pages < nr_pages)
+			continue;
+
+		start = desc->phys_addr;
+		end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);
+
+		if (end > max)
+			end = max;
+
+		if ((start + size) > end)
+			continue;
+
+		if (round_down(end - size, align) < start)
+			continue;
+
+		start = round_down(end - size, align);
+
+		/*
+		 * Don't allocate at 0x0. It will confuse code that
+		 * checks pointers against NULL.
+		 */
+		if (start == 0x0)
+			continue;
+
+		if (start > max_addr)
+			max_addr = start;
+	}
+
+	if (!max_addr)
+		status = EFI_NOT_FOUND;
+	else {
+		status = efi_call_early(allocate_pages,
+					EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
+					nr_pages, &max_addr);
+		if (status != EFI_SUCCESS) {
+			max = max_addr;
+			max_addr = 0;
+			goto again;
+		}
+
+		*addr = max_addr;
+	}
+
+	efi_call_early(free_pool, map);
+fail:
+	return status;
+}
+
+/*
+ * Allocate at the lowest possible address.
+ */
+efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
+			   unsigned long size, unsigned long align,
+			   unsigned long *addr)
+{
+	unsigned long map_size, desc_size;
+	efi_memory_desc_t *map;
+	efi_status_t status;
+	unsigned long nr_pages;
+	int i;
+
+	status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
+				    NULL, NULL);
+	if (status != EFI_SUCCESS)
+		goto fail;
+
+	/*
+	 * Enforce minimum alignment that EFI requires when requesting
+	 * a specific address.  We are doing page-based allocations,
+	 * so we must be aligned to a page.
+	 */
+	if (align < EFI_ALLOC_ALIGN)
+		align = EFI_ALLOC_ALIGN;
+
+	nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
+	for (i = 0; i < map_size / desc_size; i++) {
+		efi_memory_desc_t *desc;
+		unsigned long m = (unsigned long)map;
+		u64 start, end;
+
+		desc = (efi_memory_desc_t *)(m + (i * desc_size));
+
+		if (desc->type != EFI_CONVENTIONAL_MEMORY)
+			continue;
+
+		if (desc->num_pages < nr_pages)
+			continue;
+
+		start = desc->phys_addr;
+		end = start + desc->num_pages * (1UL << EFI_PAGE_SHIFT);
+
+		/*
+		 * Don't allocate at 0x0. It will confuse code that
+		 * checks pointers against NULL. Skip the first 8
+		 * bytes so we start at a nice even number.
+		 */
+		if (start == 0x0)
+			start += 8;
+
+		start = round_up(start, align);
+		if ((start + size) > end)
+			continue;
+
+		status = efi_call_early(allocate_pages,
+					EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
+					nr_pages, &start);
+		if (status == EFI_SUCCESS) {
+			*addr = start;
+			break;
+		}
+	}
+
+	if (i == map_size / desc_size)
+		status = EFI_NOT_FOUND;
+
+	efi_call_early(free_pool, map);
+fail:
+	return status;
+}
+
+void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
+	      unsigned long addr)
+{
+	unsigned long nr_pages;
+
+	if (!size)
+		return;
+
+	nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
+	efi_call_early(free_pages, addr, nr_pages);
+}
+
+/*
+ * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
+ * option, e.g. efi=nochunk.
+ *
+ * It should be noted that efi= is parsed in two very different
+ * environments, first in the early boot environment of the EFI boot
+ * stub, and subsequently during the kernel boot.
+ */
+efi_status_t efi_parse_options(char *cmdline)
+{
+	char *str;
+
+	/*
+	 * If no EFI parameters were specified on the cmdline we've got
+	 * nothing to do.
+	 */
+	str = strstr(cmdline, "efi=");
+	if (!str)
+		return EFI_SUCCESS;
+
+	/* Skip ahead to first argument */
+	str += strlen("efi=");
+
+	/*
+	 * Remember, because efi= is also used by the kernel we need to
+	 * skip over arguments we don't understand.
+	 */
+	while (*str) {
+		if (!strncmp(str, "nochunk", 7)) {
+			str += strlen("nochunk");
+			__chunk_size = -1UL;
+		}
+
+		/* Group words together, delimited by "," */
+		while (*str && *str != ',')
+			str++;
+
+		if (*str == ',')
+			str++;
+	}
+
+	return EFI_SUCCESS;
+}
+
+/*
+ * Check the cmdline for a LILO-style file= arguments.
+ *
+ * We only support loading a file from the same filesystem as
+ * the kernel image.
+ */
+efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
+				  efi_loaded_image_t *image,
+				  char *cmd_line, char *option_string,
+				  unsigned long max_addr,
+				  unsigned long *load_addr,
+				  unsigned long *load_size)
+{
+	struct file_info *files;
+	unsigned long file_addr;
+	u64 file_size_total;
+	efi_file_handle_t *fh = NULL;
+	efi_status_t status;
+	int nr_files;
+	char *str;
+	int i, j, k;
+
+	file_addr = 0;
+	file_size_total = 0;
+
+	str = cmd_line;
+
+	j = 0;			/* See close_handles */
+
+	if (!load_addr || !load_size)
+		return EFI_INVALID_PARAMETER;
+
+	*load_addr = 0;
+	*load_size = 0;
+
+	if (!str || !*str)
+		return EFI_SUCCESS;
+
+	for (nr_files = 0; *str; nr_files++) {
+		str = strstr(str, option_string);
+		if (!str)
+			break;
+
+		str += strlen(option_string);
+
+		/* Skip any leading slashes */
+		while (*str == '/' || *str == '\\')
+			str++;
+
+		while (*str && *str != ' ' && *str != '\n')
+			str++;
+	}
+
+	if (!nr_files)
+		return EFI_SUCCESS;
+
+	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
+				nr_files * sizeof(*files), (void **)&files);
+	if (status != EFI_SUCCESS) {
+		pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
+		goto fail;
+	}
+
+	str = cmd_line;
+	for (i = 0; i < nr_files; i++) {
+		struct file_info *file;
+		efi_char16_t filename_16[256];
+		efi_char16_t *p;
+
+		str = strstr(str, option_string);
+		if (!str)
+			break;
+
+		str += strlen(option_string);
+
+		file = &files[i];
+		p = filename_16;
+
+		/* Skip any leading slashes */
+		while (*str == '/' || *str == '\\')
+			str++;
+
+		while (*str && *str != ' ' && *str != '\n') {
+			if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
+				break;
+
+			if (*str == '/') {
+				*p++ = '\\';
+				str++;
+			} else {
+				*p++ = *str++;
+			}
+		}
+
+		*p = '\0';
+
+		/* Only open the volume once. */
+		if (!i) {
+			status = efi_open_volume(sys_table_arg, image,
+						 (void **)&fh);
+			if (status != EFI_SUCCESS)
+				goto free_files;
+		}
+
+		status = efi_file_size(sys_table_arg, fh, filename_16,
+				       (void **)&file->handle, &file->size);
+		if (status != EFI_SUCCESS)
+			goto close_handles;
+
+		file_size_total += file->size;
+	}
+
+	if (file_size_total) {
+		unsigned long addr;
+
+		/*
+		 * Multiple files need to be at consecutive addresses in memory,
+		 * so allocate enough memory for all the files.  This is used
+		 * for loading multiple files.
+		 */
+		status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
+				    &file_addr, max_addr);
+		if (status != EFI_SUCCESS) {
+			pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
+			goto close_handles;
+		}
+
+		/* We've run out of free low memory. */
+		if (file_addr > max_addr) {
+			pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
+			status = EFI_INVALID_PARAMETER;
+			goto free_file_total;
+		}
+
+		addr = file_addr;
+		for (j = 0; j < nr_files; j++) {
+			unsigned long size;
+
+			size = files[j].size;
+			while (size) {
+				unsigned long chunksize;
+				if (size > __chunk_size)
+					chunksize = __chunk_size;
+				else
+					chunksize = size;
+
+				status = efi_file_read(files[j].handle,
+						       &chunksize,
+						       (void *)addr);
+				if (status != EFI_SUCCESS) {
+					pr_efi_err(sys_table_arg, "Failed to read file\n");
+					goto free_file_total;
+				}
+				addr += chunksize;
+				size -= chunksize;
+			}
+
+			efi_file_close(files[j].handle);
+		}
+
+	}
+
+	efi_call_early(free_pool, files);
+
+	*load_addr = file_addr;
+	*load_size = file_size_total;
+
+	return status;
+
+free_file_total:
+	efi_free(sys_table_arg, file_size_total, file_addr);
+
+close_handles:
+	for (k = j; k < i; k++)
+		efi_file_close(files[k].handle);
+free_files:
+	efi_call_early(free_pool, files);
+fail:
+	*load_addr = 0;
+	*load_size = 0;
+
+	return status;
+}
+/*
+ * Relocate a kernel image, either compressed or uncompressed.
+ * In the ARM64 case, all kernel images are currently
+ * uncompressed, and as such when we relocate it we need to
+ * allocate additional space for the BSS segment. Any low
+ * memory that this function should avoid needs to be
+ * unavailable in the EFI memory map, as if the preferred
+ * address is not available the lowest available address will
+ * be used.
+ */
+efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
+				 unsigned long *image_addr,
+				 unsigned long image_size,
+				 unsigned long alloc_size,
+				 unsigned long preferred_addr,
+				 unsigned long alignment)
+{
+	unsigned long cur_image_addr;
+	unsigned long new_addr = 0;
+	efi_status_t status;
+	unsigned long nr_pages;
+	efi_physical_addr_t efi_addr = preferred_addr;
+
+	if (!image_addr || !image_size || !alloc_size)
+		return EFI_INVALID_PARAMETER;
+	if (alloc_size < image_size)
+		return EFI_INVALID_PARAMETER;
+
+	cur_image_addr = *image_addr;
+
+	/*
+	 * The EFI firmware loader could have placed the kernel image
+	 * anywhere in memory, but the kernel has restrictions on the
+	 * max physical address it can run at.  Some architectures
+	 * also have a prefered address, so first try to relocate
+	 * to the preferred address.  If that fails, allocate as low
+	 * as possible while respecting the required alignment.
+	 */
+	nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
+	status = efi_call_early(allocate_pages,
+				EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
+				nr_pages, &efi_addr);
+	new_addr = efi_addr;
+	/*
+	 * If preferred address allocation failed allocate as low as
+	 * possible.
+	 */
+	if (status != EFI_SUCCESS) {
+		status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
+				       &new_addr);
+	}
+	if (status != EFI_SUCCESS) {
+		pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
+		return status;
+	}
+
+	/*
+	 * We know source/dest won't overlap since both memory ranges
+	 * have been allocated by UEFI, so we can safely use memcpy.
+	 */
+	memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
+
+	/* Return the new address of the relocated image. */
+	*image_addr = new_addr;
+
+	return status;
+}
+
+/*
+ * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
+ * This overestimates for surrogates, but that is okay.
+ */
+static int efi_utf8_bytes(u16 c)
+{
+	return 1 + (c >= 0x80) + (c >= 0x800);
+}
+
+/*
+ * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
+ */
+static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
+{
+	unsigned int c;
+
+	while (n--) {
+		c = *src++;
+		if (n && c >= 0xd800 && c <= 0xdbff &&
+		    *src >= 0xdc00 && *src <= 0xdfff) {
+			c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
+			src++;
+			n--;
+		}
+		if (c >= 0xd800 && c <= 0xdfff)
+			c = 0xfffd; /* Unmatched surrogate */
+		if (c < 0x80) {
+			*dst++ = c;
+			continue;
+		}
+		if (c < 0x800) {
+			*dst++ = 0xc0 + (c >> 6);
+			goto t1;
+		}
+		if (c < 0x10000) {
+			*dst++ = 0xe0 + (c >> 12);
+			goto t2;
+		}
+		*dst++ = 0xf0 + (c >> 18);
+		*dst++ = 0x80 + ((c >> 12) & 0x3f);
+	t2:
+		*dst++ = 0x80 + ((c >> 6) & 0x3f);
+	t1:
+		*dst++ = 0x80 + (c & 0x3f);
+	}
+
+	return dst;
+}
+
+/*
+ * Convert the unicode UEFI command line to ASCII to pass to kernel.
+ * Size of memory allocated return in *cmd_line_len.
+ * Returns NULL on error.
+ */
+char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
+			  efi_loaded_image_t *image,
+			  int *cmd_line_len)
+{
+	const u16 *s2;
+	u8 *s1 = NULL;
+	unsigned long cmdline_addr = 0;
+	int load_options_chars = image->load_options_size / 2; /* UTF-16 */
+	const u16 *options = image->load_options;
+	int options_bytes = 0;  /* UTF-8 bytes */
+	int options_chars = 0;  /* UTF-16 chars */
+	efi_status_t status;
+	u16 zero = 0;
+
+	if (options) {
+		s2 = options;
+		while (*s2 && *s2 != '\n'
+		       && options_chars < load_options_chars) {
+			options_bytes += efi_utf8_bytes(*s2++);
+			options_chars++;
+		}
+	}
+
+	if (!options_chars) {
+		/* No command line options, so return empty string*/
+		options = &zero;
+	}
+
+	options_bytes++;	/* NUL termination */
+
+	status = efi_low_alloc(sys_table_arg, options_bytes, 0, &cmdline_addr);
+	if (status != EFI_SUCCESS)
+		return NULL;
+
+	s1 = (u8 *)cmdline_addr;
+	s2 = (const u16 *)options;
+
+	s1 = efi_utf16_to_utf8(s1, s2, options_chars);
+	*s1 = '\0';
+
+	*cmd_line_len = options_bytes;
+	return (char *)cmdline_addr;
+}
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
new file mode 100644
index 000000000..e334a01cf
--- /dev/null
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -0,0 +1,50 @@
+
+#ifndef _DRIVERS_FIRMWARE_EFI_EFISTUB_H
+#define _DRIVERS_FIRMWARE_EFI_EFISTUB_H
+
+/* error code which can't be mistaken for valid address */
+#define EFI_ERROR	(~0UL)
+
+#undef memcpy
+#undef memset
+#undef memmove
+
+void efi_char16_printk(efi_system_table_t *, efi_char16_t *);
+
+efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg, void *__image,
+			     void **__fh);
+
+efi_status_t efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
+			   efi_char16_t *filename_16, void **handle,
+			   u64 *file_sz);
+
+efi_status_t efi_file_read(void *handle, unsigned long *size, void *addr);
+
+efi_status_t efi_file_close(void *handle);
+
+unsigned long get_dram_base(efi_system_table_t *sys_table_arg);
+
+efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
+			unsigned long orig_fdt_size,
+			void *fdt, int new_fdt_size, char *cmdline_ptr,
+			u64 initrd_addr, u64 initrd_size,
+			efi_memory_desc_t *memory_map,
+			unsigned long map_size, unsigned long desc_size,
+			u32 desc_ver);
+
+efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
+					    void *handle,
+					    unsigned long *new_fdt_addr,
+					    unsigned long max_addr,
+					    u64 initrd_addr, u64 initrd_size,
+					    char *cmdline_ptr,
+					    unsigned long fdt_addr,
+					    unsigned long fdt_size);
+
+void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size);
+
+void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
+		     unsigned long desc_size, efi_memory_desc_t *runtime_map,
+		     int *count);
+
+#endif
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
new file mode 100644
index 000000000..ef5d764e2
--- /dev/null
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -0,0 +1,348 @@
+/*
+ * FDT related Helper functions used by the EFI stub on multiple
+ * architectures. This should be #included by the EFI stub
+ * implementation files.
+ *
+ * Copyright 2013 Linaro Limited; author Roy Franz
+ *
+ * This file is part of the Linux kernel, and is made available
+ * under the terms of the GNU General Public License version 2.
+ *
+ */
+
+#include <linux/efi.h>
+#include <linux/libfdt.h>
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
+			unsigned long orig_fdt_size,
+			void *fdt, int new_fdt_size, char *cmdline_ptr,
+			u64 initrd_addr, u64 initrd_size,
+			efi_memory_desc_t *memory_map,
+			unsigned long map_size, unsigned long desc_size,
+			u32 desc_ver)
+{
+	int node, prev, num_rsv;
+	int status;
+	u32 fdt_val32;
+	u64 fdt_val64;
+
+	/* Do some checks on provided FDT, if it exists*/
+	if (orig_fdt) {
+		if (fdt_check_header(orig_fdt)) {
+			pr_efi_err(sys_table, "Device Tree header not valid!\n");
+			return EFI_LOAD_ERROR;
+		}
+		/*
+		 * We don't get the size of the FDT if we get if from a
+		 * configuration table.
+		 */
+		if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
+			pr_efi_err(sys_table, "Truncated device tree! foo!\n");
+			return EFI_LOAD_ERROR;
+		}
+	}
+
+	if (orig_fdt)
+		status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
+	else
+		status = fdt_create_empty_tree(fdt, new_fdt_size);
+
+	if (status != 0)
+		goto fdt_set_fail;
+
+	/*
+	 * Delete any memory nodes present. We must delete nodes which
+	 * early_init_dt_scan_memory may try to use.
+	 */
+	prev = 0;
+	for (;;) {
+		const char *type;
+		int len;
+
+		node = fdt_next_node(fdt, prev, NULL);
+		if (node < 0)
+			break;
+
+		type = fdt_getprop(fdt, node, "device_type", &len);
+		if (type && strncmp(type, "memory", len) == 0) {
+			fdt_del_node(fdt, node);
+			continue;
+		}
+
+		prev = node;
+	}
+
+	/*
+	 * Delete all memory reserve map entries. When booting via UEFI,
+	 * kernel will use the UEFI memory map to find reserved regions.
+	 */
+	num_rsv = fdt_num_mem_rsv(fdt);
+	while (num_rsv-- > 0)
+		fdt_del_mem_rsv(fdt, num_rsv);
+
+	node = fdt_subnode_offset(fdt, 0, "chosen");
+	if (node < 0) {
+		node = fdt_add_subnode(fdt, 0, "chosen");
+		if (node < 0) {
+			status = node; /* node is error code when negative */
+			goto fdt_set_fail;
+		}
+	}
+
+	if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) {
+		status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
+				     strlen(cmdline_ptr) + 1);
+		if (status)
+			goto fdt_set_fail;
+	}
+
+	/* Set initrd address/end in device tree, if present */
+	if (initrd_size != 0) {
+		u64 initrd_image_end;
+		u64 initrd_image_start = cpu_to_fdt64(initrd_addr);
+
+		status = fdt_setprop(fdt, node, "linux,initrd-start",
+				     &initrd_image_start, sizeof(u64));
+		if (status)
+			goto fdt_set_fail;
+		initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
+		status = fdt_setprop(fdt, node, "linux,initrd-end",
+				     &initrd_image_end, sizeof(u64));
+		if (status)
+			goto fdt_set_fail;
+	}
+
+	/* Add FDT entries for EFI runtime services in chosen node. */
+	node = fdt_subnode_offset(fdt, 0, "chosen");
+	fdt_val64 = cpu_to_fdt64((u64)(unsigned long)sys_table);
+	status = fdt_setprop(fdt, node, "linux,uefi-system-table",
+			     &fdt_val64, sizeof(fdt_val64));
+	if (status)
+		goto fdt_set_fail;
+
+	fdt_val64 = cpu_to_fdt64((u64)(unsigned long)memory_map);
+	status = fdt_setprop(fdt, node, "linux,uefi-mmap-start",
+			     &fdt_val64,  sizeof(fdt_val64));
+	if (status)
+		goto fdt_set_fail;
+
+	fdt_val32 = cpu_to_fdt32(map_size);
+	status = fdt_setprop(fdt, node, "linux,uefi-mmap-size",
+			     &fdt_val32,  sizeof(fdt_val32));
+	if (status)
+		goto fdt_set_fail;
+
+	fdt_val32 = cpu_to_fdt32(desc_size);
+	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size",
+			     &fdt_val32, sizeof(fdt_val32));
+	if (status)
+		goto fdt_set_fail;
+
+	fdt_val32 = cpu_to_fdt32(desc_ver);
+	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver",
+			     &fdt_val32, sizeof(fdt_val32));
+	if (status)
+		goto fdt_set_fail;
+
+	/*
+	 * Add kernel version banner so stub/kernel match can be
+	 * verified.
+	 */
+	status = fdt_setprop_string(fdt, node, "linux,uefi-stub-kern-ver",
+			     linux_banner);
+	if (status)
+		goto fdt_set_fail;
+
+	return EFI_SUCCESS;
+
+fdt_set_fail:
+	if (status == -FDT_ERR_NOSPACE)
+		return EFI_BUFFER_TOO_SMALL;
+
+	return EFI_LOAD_ERROR;
+}
+
+#ifndef EFI_FDT_ALIGN
+#define EFI_FDT_ALIGN EFI_PAGE_SIZE
+#endif
+
+/*
+ * Allocate memory for a new FDT, then add EFI, commandline, and
+ * initrd related fields to the FDT.  This routine increases the
+ * FDT allocation size until the allocated memory is large
+ * enough.  EFI allocations are in EFI_PAGE_SIZE granules,
+ * which are fixed at 4K bytes, so in most cases the first
+ * allocation should succeed.
+ * EFI boot services are exited at the end of this function.
+ * There must be no allocations between the get_memory_map()
+ * call and the exit_boot_services() call, so the exiting of
+ * boot services is very tightly tied to the creation of the FDT
+ * with the final memory map in it.
+ */
+
+efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
+					    void *handle,
+					    unsigned long *new_fdt_addr,
+					    unsigned long max_addr,
+					    u64 initrd_addr, u64 initrd_size,
+					    char *cmdline_ptr,
+					    unsigned long fdt_addr,
+					    unsigned long fdt_size)
+{
+	unsigned long map_size, desc_size;
+	u32 desc_ver;
+	unsigned long mmap_key;
+	efi_memory_desc_t *memory_map, *runtime_map;
+	unsigned long new_fdt_size;
+	efi_status_t status;
+	int runtime_entry_count = 0;
+
+	/*
+	 * Get a copy of the current memory map that we will use to prepare
+	 * the input for SetVirtualAddressMap(). We don't have to worry about
+	 * subsequent allocations adding entries, since they could not affect
+	 * the number of EFI_MEMORY_RUNTIME regions.
+	 */
+	status = efi_get_memory_map(sys_table, &runtime_map, &map_size,
+				    &desc_size, &desc_ver, &mmap_key);
+	if (status != EFI_SUCCESS) {
+		pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n");
+		return status;
+	}
+
+	pr_efi(sys_table,
+	       "Exiting boot services and installing virtual address map...\n");
+
+	/*
+	 * Estimate size of new FDT, and allocate memory for it. We
+	 * will allocate a bigger buffer if this ends up being too
+	 * small, so a rough guess is OK here.
+	 */
+	new_fdt_size = fdt_size + EFI_PAGE_SIZE;
+	while (1) {
+		status = efi_high_alloc(sys_table, new_fdt_size, EFI_FDT_ALIGN,
+					new_fdt_addr, max_addr);
+		if (status != EFI_SUCCESS) {
+			pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n");
+			goto fail;
+		}
+
+		/*
+		 * Now that we have done our final memory allocation (and free)
+		 * we can get the memory map key  needed for
+		 * exit_boot_services().
+		 */
+		status = efi_get_memory_map(sys_table, &memory_map, &map_size,
+					    &desc_size, &desc_ver, &mmap_key);
+		if (status != EFI_SUCCESS)
+			goto fail_free_new_fdt;
+
+		status = update_fdt(sys_table,
+				    (void *)fdt_addr, fdt_size,
+				    (void *)*new_fdt_addr, new_fdt_size,
+				    cmdline_ptr, initrd_addr, initrd_size,
+				    memory_map, map_size, desc_size, desc_ver);
+
+		/* Succeeding the first time is the expected case. */
+		if (status == EFI_SUCCESS)
+			break;
+
+		if (status == EFI_BUFFER_TOO_SMALL) {
+			/*
+			 * We need to allocate more space for the new
+			 * device tree, so free existing buffer that is
+			 * too small.  Also free memory map, as we will need
+			 * to get new one that reflects the free/alloc we do
+			 * on the device tree buffer.
+			 */
+			efi_free(sys_table, new_fdt_size, *new_fdt_addr);
+			sys_table->boottime->free_pool(memory_map);
+			new_fdt_size += EFI_PAGE_SIZE;
+		} else {
+			pr_efi_err(sys_table, "Unable to constuct new device tree.\n");
+			goto fail_free_mmap;
+		}
+	}
+
+	/*
+	 * Update the memory map with virtual addresses. The function will also
+	 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
+	 * entries so that we can pass it straight into SetVirtualAddressMap()
+	 */
+	efi_get_virtmap(memory_map, map_size, desc_size, runtime_map,
+			&runtime_entry_count);
+
+	/* Now we are ready to exit_boot_services.*/
+	status = sys_table->boottime->exit_boot_services(handle, mmap_key);
+
+	if (status == EFI_SUCCESS) {
+		efi_set_virtual_address_map_t *svam;
+
+		/* Install the new virtual address map */
+		svam = sys_table->runtime->set_virtual_address_map;
+		status = svam(runtime_entry_count * desc_size, desc_size,
+			      desc_ver, runtime_map);
+
+		/*
+		 * We are beyond the point of no return here, so if the call to
+		 * SetVirtualAddressMap() failed, we need to signal that to the
+		 * incoming kernel but proceed normally otherwise.
+		 */
+		if (status != EFI_SUCCESS) {
+			int l;
+
+			/*
+			 * Set the virtual address field of all
+			 * EFI_MEMORY_RUNTIME entries to 0. This will signal
+			 * the incoming kernel that no virtual translation has
+			 * been installed.
+			 */
+			for (l = 0; l < map_size; l += desc_size) {
+				efi_memory_desc_t *p = (void *)memory_map + l;
+
+				if (p->attribute & EFI_MEMORY_RUNTIME)
+					p->virt_addr = 0;
+			}
+		}
+		return EFI_SUCCESS;
+	}
+
+	pr_efi_err(sys_table, "Exit boot services failed.\n");
+
+fail_free_mmap:
+	sys_table->boottime->free_pool(memory_map);
+
+fail_free_new_fdt:
+	efi_free(sys_table, new_fdt_size, *new_fdt_addr);
+
+fail:
+	sys_table->boottime->free_pool(runtime_map);
+	return EFI_LOAD_ERROR;
+}
+
+void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size)
+{
+	efi_guid_t fdt_guid = DEVICE_TREE_GUID;
+	efi_config_table_t *tables;
+	void *fdt;
+	int i;
+
+	tables = (efi_config_table_t *) sys_table->tables;
+	fdt = NULL;
+
+	for (i = 0; i < sys_table->nr_tables; i++)
+		if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) {
+			fdt = (void *) tables[i].table;
+			if (fdt_check_header(fdt) != 0) {
+				pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
+				return NULL;
+			}
+			*fdt_size = fdt_totalsize(fdt);
+			break;
+	 }
+
+	return fdt;
+}