[mirror_ubuntu-bionic-kernel.git] / drivers / firmware / efi / libstub / arm-stub.c

/*
 * 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 <linux/sort.h>
#include <asm/efi.h>

#include "efistub.h"

/*
 * 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.
 * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
 * map everything below 1 GB. (512 MB is a reasonable upper bound for the
 * entire footprint of the UEFI runtime services memory regions)
 */
#define EFI_RT_VIRTUAL_BASE	SZ_512M
#define EFI_RT_VIRTUAL_SIZE	SZ_512M

#ifdef CONFIG_ARM64
# define EFI_RT_VIRTUAL_LIMIT	TASK_SIZE_64
#else
# define EFI_RT_VIRTUAL_LIMIT	TASK_SIZE
#endif

static u64 virtmap_base = EFI_RT_VIRTUAL_BASE;

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;
}

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);
}

static struct screen_info *setup_graphics(efi_system_table_t *sys_table_arg)
{
	efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
	efi_status_t status;
	unsigned long size;
	void **gop_handle = NULL;
	struct screen_info *si = NULL;

	size = 0;
	status = efi_call_early(locate_handle, EFI_LOCATE_BY_PROTOCOL,
				&gop_proto, NULL, &size, gop_handle);
	if (status == EFI_BUFFER_TOO_SMALL) {
		si = alloc_screen_info(sys_table_arg);
		if (!si)
			return NULL;
		efi_setup_gop(sys_table_arg, si, &gop_proto, size);
	}
	return si;
}

/*
 * 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;
	enum efi_secureboot_mode secure_boot;
	struct screen_info *si;

	/* Check if we were booted by the EFI firmware */
	if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
		goto fail;

	status = check_platform_features(sys_table);
	if (status != EFI_SUCCESS)
		goto fail;

	/*
	 * 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;
	}

	/*
	 * 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;
	}

	if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
	    IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
	    cmdline_size == 0)
		efi_parse_options(CONFIG_CMDLINE);

	if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0)
		efi_parse_options(cmdline_ptr);

	pr_efi(sys_table, "Booting Linux Kernel...\n");

	si = setup_graphics(sys_table);

	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_free_cmdline;
	}

	/* Ask the firmware to clear memory on unclean shutdown */
	efi_enable_reset_attack_mitigation(sys_table);

	secure_boot = efi_get_secureboot(sys_table);

	/*
	 * Unauthenticated device tree data is a security hazard, so ignore
	 * 'dtb=' unless UEFI Secure Boot is disabled.  We assume that secure
	 * boot is enabled if we can't determine its state.
	 */
	if (secure_boot != efi_secureboot_mode_disabled &&
	    strstr(cmdline_ptr, "dtb=")) {
		pr_efi(sys_table, "Ignoring DTB from command line.\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_image;
		}
	}

	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=",
				      efi_get_max_initrd_addr(dram_base,
							      *image_addr),
				      (unsigned long *)&initrd_addr,
				      (unsigned long *)&initrd_size);
	if (status != EFI_SUCCESS)
		pr_efi_err(sys_table, "Failed initrd from command line!\n");

	efi_random_get_seed(sys_table);

	if (!nokaslr()) {
		/*
		 * Randomize the base of the UEFI runtime services region.
		 * Preserve the 2 MB alignment of the region by taking a
		 * shift of 21 bit positions into account when scaling
		 * the headroom value using a 32-bit random value.
		 */
		static const u64 headroom = EFI_RT_VIRTUAL_LIMIT -
					    EFI_RT_VIRTUAL_BASE -
					    EFI_RT_VIRTUAL_SIZE;
		u32 rnd;

		status = efi_get_random_bytes(sys_table, sizeof(rnd),
					      (u8 *)&rnd);
		if (status == EFI_SUCCESS) {
			virtmap_base = EFI_RT_VIRTUAL_BASE +
				       (((headroom >> 21) * rnd) >> (32 - 21));
		}
	}

	new_fdt_addr = fdt_addr;
	status = allocate_new_fdt_and_exit_boot(sys_table, handle,
				&new_fdt_addr, efi_get_max_fdt_addr(dram_base),
				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_image:
	efi_free(sys_table, image_size, *image_addr);
	efi_free(sys_table, reserve_size, reserve_addr);
fail_free_cmdline:
	free_screen_info(sys_table, si);
	efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
fail:
	return EFI_ERROR;
}

static int cmp_mem_desc(const void *l, const void *r)
{
	const efi_memory_desc_t *left = l, *right = r;

	return (left->phys_addr > right->phys_addr) ? 1 : -1;
}

/*
 * Returns whether region @left ends exactly where region @right starts,
 * or false if either argument is NULL.
 */
static bool regions_are_adjacent(efi_memory_desc_t *left,
				 efi_memory_desc_t *right)
{
	u64 left_end;

	if (left == NULL || right == NULL)
		return false;

	left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;

	return left_end == right->phys_addr;
}

/*
 * Returns whether region @left and region @right have compatible memory type
 * mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
 */
static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
						      efi_memory_desc_t *right)
{
	static const u64 mem_type_mask = EFI_MEMORY_WB | EFI_MEMORY_WT |
					 EFI_MEMORY_WC | EFI_MEMORY_UC |
					 EFI_MEMORY_RUNTIME;

	return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
}

/*
 * 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 = virtmap_base;
	efi_memory_desc_t *in, *prev = NULL, *out = runtime_map;
	int l;

	/*
	 * To work around potential issues with the Properties Table feature
	 * introduced in UEFI 2.5, which may split PE/COFF executable images
	 * in memory into several RuntimeServicesCode and RuntimeServicesData
	 * regions, we need to preserve the relative offsets between adjacent
	 * EFI_MEMORY_RUNTIME regions with the same memory type attributes.
	 * The easiest way to find adjacent regions is to sort the memory map
	 * before traversing it.
	 */
	sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);

	for (l = 0; l < map_size; l += desc_size, prev = in) {
		u64 paddr, size;

		in = (void *)memory_map + l;
		if (!(in->attribute & EFI_MEMORY_RUNTIME))
			continue;

		paddr = in->phys_addr;
		size = in->num_pages * EFI_PAGE_SIZE;

		/*
		 * Make the mapping compatible with 64k pages: this allows
		 * a 4k page size kernel to kexec a 64k page size kernel and
		 * vice versa.
		 */
		if (!regions_are_adjacent(prev, in) ||
		    !regions_have_compatible_memory_type_attrs(prev, in)) {

			paddr = round_down(in->phys_addr, SZ_64K);
			size += in->phys_addr - paddr;

			/*
			 * 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);
			else
				efi_virt_base = round_up(efi_virt_base, SZ_64K);
		}

		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;
	}
}
Commit	Line	Data
3c7f2550 MS	1	/*
	2	* EFI stub implementation that is shared by arm and arm64 architectures.
	3	* This should be #included by the EFI stub implementation files.
	4	*
	5	* Copyright (C) 2013,2014 Linaro Limited
	6	* Roy Franz <roy.franz@linaro.org
	7	* Copyright (C) 2013 Red Hat, Inc.
	8	* Mark Salter <msalter@redhat.com>
	9	*
	10	* This file is part of the Linux kernel, and is made available under the
	11	* terms of the GNU General Public License version 2.
	12	*
	13	*/
	14
bd669475	15	#include <linux/efi.h>
0ce3cc00	16	#include <linux/sort.h>
bd669475 AB	17	#include <asm/efi.h>
	18
	19	#include "efistub.h"
	20
e69176d6 AB	21	/*
	22	* This is the base address at which to start allocating virtual memory ranges
	23	* for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
	24	* any allocation we choose, and eliminate the risk of a conflict after kexec.
	25	* The value chosen is the largest non-zero power of 2 suitable for this purpose
	26	* both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
	27	* be mapped efficiently.
	28	* Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
	29	* map everything below 1 GB. (512 MB is a reasonable upper bound for the
	30	* entire footprint of the UEFI runtime services memory regions)
	31	*/
	32	#define EFI_RT_VIRTUAL_BASE SZ_512M
	33	#define EFI_RT_VIRTUAL_SIZE SZ_512M
	34
197decef AB	35	#ifdef CONFIG_ARM64
	36	# define EFI_RT_VIRTUAL_LIMIT TASK_SIZE_64
	37	#else
	38	# define EFI_RT_VIRTUAL_LIMIT TASK_SIZE
	39	#endif
	40
e69176d6 AB	41	static u64 virtmap_base = EFI_RT_VIRTUAL_BASE;
e69176d6 AB	42
bd669475 AB	43	efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
bd669475 AB	44	void __image, void *__fh)
3c7f2550 MS	45	{
	46	efi_file_io_interface_t *io;
	47	efi_loaded_image_t *image = __image;
	48	efi_file_handle_t *fh;
	49	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
	50	efi_status_t status;
	51	void handle = (void )(unsigned long)image->device_handle;
	52
	53	status = sys_table_arg->boottime->handle_protocol(handle,
	54	&fs_proto, (void **)&io);
	55	if (status != EFI_SUCCESS) {
	56	efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
	57	return status;
	58	}
	59
	60	status = io->open_volume(io, &fh);
	61	if (status != EFI_SUCCESS)
	62	efi_printk(sys_table_arg, "Failed to open volume\n");
	63
	64	*__fh = fh;
	65	return status;
	66	}
bd669475	67
bd669475	68	void efi_char16_printk(efi_system_table_t *sys_table_arg,
3c7f2550 MS	69	efi_char16_t *str)
	70	{
	71	struct efi_simple_text_output_protocol *out;
	72
	73	out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
	74	out->output_string(out, str);
	75	}
	76
f0827e18 AB	77	static struct screen_info setup_graphics(efi_system_table_t sys_table_arg)
	78	{
	79	efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
	80	efi_status_t status;
	81	unsigned long size;
	82	void **gop_handle = NULL;
	83	struct screen_info *si = NULL;
	84
	85	size = 0;
	86	status = efi_call_early(locate_handle, EFI_LOCATE_BY_PROTOCOL,
	87	&gop_proto, NULL, &size, gop_handle);
	88	if (status == EFI_BUFFER_TOO_SMALL) {
	89	si = alloc_screen_info(sys_table_arg);
	90	if (!si)
	91	return NULL;
	92	efi_setup_gop(sys_table_arg, si, &gop_proto, size);
	93	}
	94	return si;
	95	}
3c7f2550 MS	96
	97	/*
	98	* This function handles the architcture specific differences between arm and
	99	* arm64 regarding where the kernel image must be loaded and any memory that
	100	* must be reserved. On failure it is required to free all
	101	* all allocations it has made.
	102	*/
bd669475 AB	103	efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
	104	unsigned long *image_addr,
	105	unsigned long *image_size,
	106	unsigned long *reserve_addr,
	107	unsigned long *reserve_size,
	108	unsigned long dram_base,
	109	efi_loaded_image_t *image);
3c7f2550 MS	110	/*
	111	* EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
	112	* that is described in the PE/COFF header. Most of the code is the same
	113	* for both archictectures, with the arch-specific code provided in the
	114	* handle_kernel_image() function.
	115	*/
ddeeefe2	116	unsigned long efi_entry(void handle, efi_system_table_t sys_table,
3c7f2550 MS	117	unsigned long *image_addr)
	118	{
	119	efi_loaded_image_t *image;
	120	efi_status_t status;
	121	unsigned long image_size = 0;
	122	unsigned long dram_base;
	123	/* addr/point and size pairs for memory management*/
	124	unsigned long initrd_addr;
	125	u64 initrd_size = 0;
345c736e	126	unsigned long fdt_addr = 0; /* Original DTB */
a643375f	127	unsigned long fdt_size = 0;
3c7f2550 MS	128	char *cmdline_ptr = NULL;
	129	int cmdline_size = 0;
	130	unsigned long new_fdt_addr;
	131	efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
	132	unsigned long reserve_addr = 0;
	133	unsigned long reserve_size = 0;
de8cb458	134	enum efi_secureboot_mode secure_boot;
f0827e18	135	struct screen_info *si;
3c7f2550 MS	136
	137	/* Check if we were booted by the EFI firmware */
	138	if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
	139	goto fail;
	140
b9d6769b AB	141	status = check_platform_features(sys_table);
	142	if (status != EFI_SUCCESS)
	143	goto fail;
	144
3c7f2550 MS	145	/*
	146	* Get a handle to the loaded image protocol. This is used to get
	147	* information about the running image, such as size and the command
	148	* line.
	149	*/
	150	status = sys_table->boottime->handle_protocol(handle,
	151	&loaded_image_proto, (void *)&image);
	152	if (status != EFI_SUCCESS) {
	153	pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
	154	goto fail;
	155	}
	156
	157	dram_base = get_dram_base(sys_table);
	158	if (dram_base == EFI_ERROR) {
	159	pr_efi_err(sys_table, "Failed to find DRAM base\n");
	160	goto fail;
	161	}
3c7f2550 MS	162
	163	/*
	164	* Get the command line from EFI, using the LOADED_IMAGE
	165	* protocol. We are going to copy the command line into the
	166	* device tree, so this can be allocated anywhere.
	167	*/
	168	cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
	169	if (!cmdline_ptr) {
	170	pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
2b5fe07a AB	171	goto fail;
	172	}
	173
eeff7d63 AB	174	if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) \|\|
	175	IS_ENABLED(CONFIG_CMDLINE_FORCE) \|\|
	176	cmdline_size == 0)
	177	efi_parse_options(CONFIG_CMDLINE);
	178
	179	if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0)
	180	efi_parse_options(cmdline_ptr);
	181
	182	pr_efi(sys_table, "Booting Linux Kernel...\n");
	183
f0827e18 AB	184	si = setup_graphics(sys_table);
f0827e18 AB	185
2b5fe07a AB	186	status = handle_kernel_image(sys_table, image_addr, &image_size,
	187	&reserve_addr,
	188	&reserve_size,
	189	dram_base, image);
	190	if (status != EFI_SUCCESS) {
	191	pr_efi_err(sys_table, "Failed to relocate kernel\n");
	192	goto fail_free_cmdline;
3c7f2550 MS	193	}
3c7f2550 MS	194
ccc829ba MG	195	/* Ask the firmware to clear memory on unclean shutdown */
	196	efi_enable_reset_attack_mitigation(sys_table);
	197
73a64925	198	secure_boot = efi_get_secureboot(sys_table);
73a64925	199
345c736e	200	/*
de8cb458 DH	201	* Unauthenticated device tree data is a security hazard, so ignore
	202	* 'dtb=' unless UEFI Secure Boot is disabled. We assume that secure
	203	* boot is enabled if we can't determine its state.
345c736e	204	*/
de8cb458 DH	205	if (secure_boot != efi_secureboot_mode_disabled &&
de8cb458 DH	206	strstr(cmdline_ptr, "dtb=")) {
73a64925	207	pr_efi(sys_table, "Ignoring DTB from command line.\n");
345c736e	208	} else {
3c7f2550 MS	209	status = handle_cmdline_files(sys_table, image, cmdline_ptr,
3c7f2550 MS	210	"dtb=",
a643375f	211	~0UL, &fdt_addr, &fdt_size);
3c7f2550 MS	212
	213	if (status != EFI_SUCCESS) {
	214	pr_efi_err(sys_table, "Failed to load device tree!\n");
2b5fe07a	215	goto fail_free_image;
3c7f2550 MS	216	}
3c7f2550 MS	217	}
0bcaa904 MR	218
	219	if (fdt_addr) {
	220	pr_efi(sys_table, "Using DTB from command line\n");
	221	} else {
345c736e	222	/* Look for a device tree configuration table entry. */
a643375f	223	fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
0bcaa904 MR	224	if (fdt_addr)
	225	pr_efi(sys_table, "Using DTB from configuration table\n");
	226	}
	227
	228	if (!fdt_addr)
	229	pr_efi(sys_table, "Generating empty DTB\n");
3c7f2550	230
138728dd AB	231	status = handle_cmdline_files(sys_table, image, cmdline_ptr, "initrd=",
	232	efi_get_max_initrd_addr(dram_base,
	233	*image_addr),
3c7f2550 MS	234	(unsigned long *)&initrd_addr,
	235	(unsigned long *)&initrd_size);
	236	if (status != EFI_SUCCESS)
	237	pr_efi_err(sys_table, "Failed initrd from command line!\n");
	238
568bc4e8 AB	239	efi_random_get_seed(sys_table);
568bc4e8 AB	240
e69176d6 AB	241	if (!nokaslr()) {
	242	/*
	243	* Randomize the base of the UEFI runtime services region.
	244	* Preserve the 2 MB alignment of the region by taking a
	245	* shift of 21 bit positions into account when scaling
	246	* the headroom value using a 32-bit random value.
	247	*/
197decef AB	248	static const u64 headroom = EFI_RT_VIRTUAL_LIMIT -
	249	EFI_RT_VIRTUAL_BASE -
	250	EFI_RT_VIRTUAL_SIZE;
e69176d6 AB	251	u32 rnd;
	252
	253	status = efi_get_random_bytes(sys_table, sizeof(rnd),
	254	(u8 *)&rnd);
	255	if (status == EFI_SUCCESS) {
	256	virtmap_base = EFI_RT_VIRTUAL_BASE +
	257	(((headroom >> 21) * rnd) >> (32 - 21));
	258	}
	259	}
	260
3c7f2550 MS	261	new_fdt_addr = fdt_addr;
3c7f2550 MS	262	status = allocate_new_fdt_and_exit_boot(sys_table, handle,
138728dd	263	&new_fdt_addr, efi_get_max_fdt_addr(dram_base),
3c7f2550 MS	264	initrd_addr, initrd_size, cmdline_ptr,
	265	fdt_addr, fdt_size);
	266
	267	/*
	268	* If all went well, we need to return the FDT address to the
	269	* calling function so it can be passed to kernel as part of
	270	* the kernel boot protocol.
	271	*/
	272	if (status == EFI_SUCCESS)
	273	return new_fdt_addr;
	274
	275	pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
	276
	277	efi_free(sys_table, initrd_size, initrd_addr);
	278	efi_free(sys_table, fdt_size, fdt_addr);
	279
3c7f2550 MS	280	fail_free_image:
	281	efi_free(sys_table, image_size, *image_addr);
	282	efi_free(sys_table, reserve_size, reserve_addr);
2b5fe07a	283	fail_free_cmdline:
f0827e18	284	free_screen_info(sys_table, si);
2b5fe07a	285	efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
3c7f2550 MS	286	fail:
	287	return EFI_ERROR;
	288	}
f3cdfd23	289
0ce3cc00 AB	290	static int cmp_mem_desc(const void l, const void r)
	291	{
	292	const efi_memory_desc_t left = l, right = r;
	293
	294	return (left->phys_addr > right->phys_addr) ? 1 : -1;
	295	}
	296
	297	/*
	298	* Returns whether region @left ends exactly where region @right starts,
	299	* or false if either argument is NULL.
	300	*/
	301	static bool regions_are_adjacent(efi_memory_desc_t *left,
	302	efi_memory_desc_t *right)
	303	{
	304	u64 left_end;
	305
	306	if (left == NULL \|\| right == NULL)
	307	return false;
	308
	309	left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;
	310
	311	return left_end == right->phys_addr;
	312	}
	313
	314	/*
	315	* Returns whether region @left and region @right have compatible memory type
	316	* mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
	317	*/
	318	static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
	319	efi_memory_desc_t *right)
	320	{
	321	static const u64 mem_type_mask = EFI_MEMORY_WB \| EFI_MEMORY_WT \|
	322	EFI_MEMORY_WC \| EFI_MEMORY_UC \|
	323	EFI_MEMORY_RUNTIME;
	324
	325	return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
	326	}
	327
f3cdfd23 AB	328	/*
	329	* efi_get_virtmap() - create a virtual mapping for the EFI memory map
	330	*
	331	* This function populates the virt_addr fields of all memory region descriptors
	332	* in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
	333	* are also copied to @runtime_map, and their total count is returned in @count.
	334	*/
	335	void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
	336	unsigned long desc_size, efi_memory_desc_t *runtime_map,
	337	int *count)
	338	{
e69176d6	339	u64 efi_virt_base = virtmap_base;
0ce3cc00	340	efi_memory_desc_t in, prev = NULL, *out = runtime_map;
f3cdfd23 AB	341	int l;
f3cdfd23 AB	342
0ce3cc00 AB	343	/*
	344	* To work around potential issues with the Properties Table feature
	345	* introduced in UEFI 2.5, which may split PE/COFF executable images
	346	* in memory into several RuntimeServicesCode and RuntimeServicesData
	347	* regions, we need to preserve the relative offsets between adjacent
	348	* EFI_MEMORY_RUNTIME regions with the same memory type attributes.
	349	* The easiest way to find adjacent regions is to sort the memory map
	350	* before traversing it.
	351	*/
	352	sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);
	353
	354	for (l = 0; l < map_size; l += desc_size, prev = in) {
f3cdfd23 AB	355	u64 paddr, size;
f3cdfd23 AB	356
0ce3cc00	357	in = (void *)memory_map + l;
f3cdfd23 AB	358	if (!(in->attribute & EFI_MEMORY_RUNTIME))
	359	continue;
	360
0ce3cc00 AB	361	paddr = in->phys_addr;
	362	size = in->num_pages * EFI_PAGE_SIZE;
	363
f3cdfd23 AB	364	/*
	365	* Make the mapping compatible with 64k pages: this allows
	366	* a 4k page size kernel to kexec a 64k page size kernel and
	367	* vice versa.
	368	*/
0ce3cc00 AB	369	if (!regions_are_adjacent(prev, in) \|\|
	370	!regions_have_compatible_memory_type_attrs(prev, in)) {
	371
	372	paddr = round_down(in->phys_addr, SZ_64K);
	373	size += in->phys_addr - paddr;
	374
	375	/*
	376	* Avoid wasting memory on PTEs by choosing a virtual
	377	* base that is compatible with section mappings if this
	378	* region has the appropriate size and physical
	379	* alignment. (Sections are 2 MB on 4k granule kernels)
	380	*/
	381	if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
	382	efi_virt_base = round_up(efi_virt_base, SZ_2M);
	383	else
	384	efi_virt_base = round_up(efi_virt_base, SZ_64K);
	385	}
f3cdfd23 AB	386
	387	in->virt_addr = efi_virt_base + in->phys_addr - paddr;
	388	efi_virt_base += size;
	389
	390	memcpy(out, in, desc_size);
	391	out = (void *)out + desc_size;
	392	++*count;
	393	}
	394	}