[mirror_ubuntu-hirsute-kernel.git] / drivers / firmware / efi / libstub / fdt.c

/*
 * 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;

	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 construct 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;
}
Commit	Line	Data
263b4a30 RF	1	/*
	2	* FDT related Helper functions used by the EFI stub on multiple
	3	* architectures. This should be #included by the EFI stub
	4	* implementation files.
	5	*
	6	* Copyright 2013 Linaro Limited; author Roy Franz
	7	*
	8	* This file is part of the Linux kernel, and is made available
	9	* under the terms of the GNU General Public License version 2.
	10	*
	11	*/
	12
bd669475 AB	13	#include <linux/efi.h>
	14	#include <linux/libfdt.h>
	15	#include <asm/efi.h>
	16
f3cdfd23 AB	17	#include "efistub.h"
f3cdfd23 AB	18
bd669475 AB	19	efi_status_t update_fdt(efi_system_table_t sys_table, void orig_fdt,
	20	unsigned long orig_fdt_size,
	21	void fdt, int new_fdt_size, char cmdline_ptr,
	22	u64 initrd_addr, u64 initrd_size,
	23	efi_memory_desc_t *memory_map,
	24	unsigned long map_size, unsigned long desc_size,
	25	u32 desc_ver)
263b4a30	26	{
0ceac9e0	27	int node, prev, num_rsv;
263b4a30 RF	28	int status;
	29	u32 fdt_val32;
	30	u64 fdt_val64;
	31
263b4a30 RF	32	/* Do some checks on provided FDT, if it exists*/
	33	if (orig_fdt) {
	34	if (fdt_check_header(orig_fdt)) {
	35	pr_efi_err(sys_table, "Device Tree header not valid!\n");
	36	return EFI_LOAD_ERROR;
	37	}
	38	/*
	39	* We don't get the size of the FDT if we get if from a
	40	* configuration table.
	41	*/
	42	if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
	43	pr_efi_err(sys_table, "Truncated device tree! foo!\n");
	44	return EFI_LOAD_ERROR;
	45	}
	46	}
	47
	48	if (orig_fdt)
	49	status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
	50	else
	51	status = fdt_create_empty_tree(fdt, new_fdt_size);
	52
	53	if (status != 0)
	54	goto fdt_set_fail;
	55
	56	/*
	57	* Delete any memory nodes present. We must delete nodes which
	58	* early_init_dt_scan_memory may try to use.
	59	*/
	60	prev = 0;
	61	for (;;) {
6fb8cc82	62	const char *type;
263b4a30 RF	63	int len;
	64
	65	node = fdt_next_node(fdt, prev, NULL);
	66	if (node < 0)
	67	break;
	68
	69	type = fdt_getprop(fdt, node, "device_type", &len);
	70	if (type && strncmp(type, "memory", len) == 0) {
	71	fdt_del_node(fdt, node);
	72	continue;
	73	}
	74
	75	prev = node;
	76	}
	77
0ceac9e0 MS	78	/*
	79	* Delete all memory reserve map entries. When booting via UEFI,
	80	* kernel will use the UEFI memory map to find reserved regions.
	81	*/
	82	num_rsv = fdt_num_mem_rsv(fdt);
	83	while (num_rsv-- > 0)
	84	fdt_del_mem_rsv(fdt, num_rsv);
	85
263b4a30 RF	86	node = fdt_subnode_offset(fdt, 0, "chosen");
	87	if (node < 0) {
	88	node = fdt_add_subnode(fdt, 0, "chosen");
	89	if (node < 0) {
	90	status = node; /* node is error code when negative */
	91	goto fdt_set_fail;
	92	}
	93	}
	94
	95	if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) {
	96	status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
	97	strlen(cmdline_ptr) + 1);
	98	if (status)
	99	goto fdt_set_fail;
	100	}
	101
	102	/* Set initrd address/end in device tree, if present */
	103	if (initrd_size != 0) {
	104	u64 initrd_image_end;
	105	u64 initrd_image_start = cpu_to_fdt64(initrd_addr);
	106
	107	status = fdt_setprop(fdt, node, "linux,initrd-start",
	108	&initrd_image_start, sizeof(u64));
	109	if (status)
	110	goto fdt_set_fail;
	111	initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
	112	status = fdt_setprop(fdt, node, "linux,initrd-end",
	113	&initrd_image_end, sizeof(u64));
	114	if (status)
	115	goto fdt_set_fail;
	116	}
	117
	118	/* Add FDT entries for EFI runtime services in chosen node. */
	119	node = fdt_subnode_offset(fdt, 0, "chosen");
	120	fdt_val64 = cpu_to_fdt64((u64)(unsigned long)sys_table);
	121	status = fdt_setprop(fdt, node, "linux,uefi-system-table",
	122	&fdt_val64, sizeof(fdt_val64));
	123	if (status)
	124	goto fdt_set_fail;
	125
	126	fdt_val64 = cpu_to_fdt64((u64)(unsigned long)memory_map);
	127	status = fdt_setprop(fdt, node, "linux,uefi-mmap-start",
	128	&fdt_val64, sizeof(fdt_val64));
	129	if (status)
	130	goto fdt_set_fail;
	131
	132	fdt_val32 = cpu_to_fdt32(map_size);
	133	status = fdt_setprop(fdt, node, "linux,uefi-mmap-size",
	134	&fdt_val32, sizeof(fdt_val32));
	135	if (status)
	136	goto fdt_set_fail;
	137
	138	fdt_val32 = cpu_to_fdt32(desc_size);
	139	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size",
	140	&fdt_val32, sizeof(fdt_val32));
	141	if (status)
	142	goto fdt_set_fail;
	143
	144	fdt_val32 = cpu_to_fdt32(desc_ver);
	145	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver",
	146	&fdt_val32, sizeof(fdt_val32));
	147	if (status)
	148	goto fdt_set_fail;
	149
263b4a30 RF	150	return EFI_SUCCESS;
	151
	152	fdt_set_fail:
	153	if (status == -FDT_ERR_NOSPACE)
	154	return EFI_BUFFER_TOO_SMALL;
	155
	156	return EFI_LOAD_ERROR;
	157	}
	158
	159	#ifndef EFI_FDT_ALIGN
	160	#define EFI_FDT_ALIGN EFI_PAGE_SIZE
	161	#endif
	162
	163	/*
	164	* Allocate memory for a new FDT, then add EFI, commandline, and
	165	* initrd related fields to the FDT. This routine increases the
	166	* FDT allocation size until the allocated memory is large
	167	* enough. EFI allocations are in EFI_PAGE_SIZE granules,
	168	* which are fixed at 4K bytes, so in most cases the first
	169	* allocation should succeed.
	170	* EFI boot services are exited at the end of this function.
	171	* There must be no allocations between the get_memory_map()
	172	* call and the exit_boot_services() call, so the exiting of
	173	* boot services is very tightly tied to the creation of the FDT
	174	* with the final memory map in it.
	175	*/
	176
	177	efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
	178	void *handle,
	179	unsigned long *new_fdt_addr,
	180	unsigned long max_addr,
	181	u64 initrd_addr, u64 initrd_size,
	182	char *cmdline_ptr,
	183	unsigned long fdt_addr,
	184	unsigned long fdt_size)
	185	{
	186	unsigned long map_size, desc_size;
	187	u32 desc_ver;
	188	unsigned long mmap_key;
f3cdfd23	189	efi_memory_desc_t memory_map, runtime_map;
263b4a30 RF	190	unsigned long new_fdt_size;
263b4a30 RF	191	efi_status_t status;
f3cdfd23 AB	192	int runtime_entry_count = 0;
	193
	194	/*
	195	* Get a copy of the current memory map that we will use to prepare
	196	* the input for SetVirtualAddressMap(). We don't have to worry about
	197	* subsequent allocations adding entries, since they could not affect
	198	* the number of EFI_MEMORY_RUNTIME regions.
	199	*/
	200	status = efi_get_memory_map(sys_table, &runtime_map, &map_size,
	201	&desc_size, &desc_ver, &mmap_key);
	202	if (status != EFI_SUCCESS) {
	203	pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n");
	204	return status;
	205	}
	206
	207	pr_efi(sys_table,
	208	"Exiting boot services and installing virtual address map...\n");
263b4a30 RF	209
	210	/*
	211	* Estimate size of new FDT, and allocate memory for it. We
	212	* will allocate a bigger buffer if this ends up being too
	213	* small, so a rough guess is OK here.
	214	*/
	215	new_fdt_size = fdt_size + EFI_PAGE_SIZE;
	216	while (1) {
	217	status = efi_high_alloc(sys_table, new_fdt_size, EFI_FDT_ALIGN,
	218	new_fdt_addr, max_addr);
	219	if (status != EFI_SUCCESS) {
	220	pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n");
	221	goto fail;
	222	}
	223
	224	/*
	225	* Now that we have done our final memory allocation (and free)
	226	* we can get the memory map key needed for
	227	* exit_boot_services().
	228	*/
	229	status = efi_get_memory_map(sys_table, &memory_map, &map_size,
	230	&desc_size, &desc_ver, &mmap_key);
	231	if (status != EFI_SUCCESS)
	232	goto fail_free_new_fdt;
	233
	234	status = update_fdt(sys_table,
	235	(void *)fdt_addr, fdt_size,
	236	(void )new_fdt_addr, new_fdt_size,
	237	cmdline_ptr, initrd_addr, initrd_size,
	238	memory_map, map_size, desc_size, desc_ver);
	239
	240	/* Succeeding the first time is the expected case. */
	241	if (status == EFI_SUCCESS)
	242	break;
	243
	244	if (status == EFI_BUFFER_TOO_SMALL) {
	245	/*
	246	* We need to allocate more space for the new
	247	* device tree, so free existing buffer that is
	248	* too small. Also free memory map, as we will need
	249	* to get new one that reflects the free/alloc we do
	250	* on the device tree buffer.
	251	*/
	252	efi_free(sys_table, new_fdt_size, *new_fdt_addr);
	253	sys_table->boottime->free_pool(memory_map);
	254	new_fdt_size += EFI_PAGE_SIZE;
	255	} else {
e3d132d1	256	pr_efi_err(sys_table, "Unable to construct new device tree.\n");
263b4a30 RF	257	goto fail_free_mmap;
	258	}
	259	}
	260
f3cdfd23 AB	261	/*
	262	* Update the memory map with virtual addresses. The function will also
	263	* populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
	264	* entries so that we can pass it straight into SetVirtualAddressMap()
	265	*/
	266	efi_get_virtmap(memory_map, map_size, desc_size, runtime_map,
	267	&runtime_entry_count);
	268
263b4a30 RF	269	/* Now we are ready to exit_boot_services.*/
	270	status = sys_table->boottime->exit_boot_services(handle, mmap_key);
	271
f3cdfd23 AB	272	if (status == EFI_SUCCESS) {
f3cdfd23 AB	273	efi_set_virtual_address_map_t *svam;
263b4a30	274
f3cdfd23 AB	275	/* Install the new virtual address map */
	276	svam = sys_table->runtime->set_virtual_address_map;
	277	status = svam(runtime_entry_count * desc_size, desc_size,
	278	desc_ver, runtime_map);
	279
	280	/*
	281	* We are beyond the point of no return here, so if the call to
	282	* SetVirtualAddressMap() failed, we need to signal that to the
	283	* incoming kernel but proceed normally otherwise.
	284	*/
	285	if (status != EFI_SUCCESS) {
	286	int l;
	287
	288	/*
	289	* Set the virtual address field of all
	290	* EFI_MEMORY_RUNTIME entries to 0. This will signal
	291	* the incoming kernel that no virtual translation has
	292	* been installed.
	293	*/
	294	for (l = 0; l < map_size; l += desc_size) {
	295	efi_memory_desc_t p = (void )memory_map + l;
	296
	297	if (p->attribute & EFI_MEMORY_RUNTIME)
	298	p->virt_addr = 0;
	299	}
	300	}
	301	return EFI_SUCCESS;
	302	}
263b4a30 RF	303
	304	pr_efi_err(sys_table, "Exit boot services failed.\n");
	305
	306	fail_free_mmap:
	307	sys_table->boottime->free_pool(memory_map);
	308
	309	fail_free_new_fdt:
	310	efi_free(sys_table, new_fdt_size, *new_fdt_addr);
	311
	312	fail:
f3cdfd23	313	sys_table->boottime->free_pool(runtime_map);
263b4a30 RF	314	return EFI_LOAD_ERROR;
	315	}
	316
a643375f	317	void get_fdt(efi_system_table_t sys_table, unsigned long *fdt_size)
263b4a30 RF	318	{
	319	efi_guid_t fdt_guid = DEVICE_TREE_GUID;
	320	efi_config_table_t *tables;
	321	void *fdt;
	322	int i;
	323
	324	tables = (efi_config_table_t *) sys_table->tables;
	325	fdt = NULL;
	326
	327	for (i = 0; i < sys_table->nr_tables; i++)
	328	if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) {
	329	fdt = (void *) tables[i].table;
a643375f AB	330	if (fdt_check_header(fdt) != 0) {
	331	pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
	332	return NULL;
	333	}
	334	*fdt_size = fdt_totalsize(fdt);
263b4a30 RF	335	break;
	336	}
	337
	338	return fdt;
	339	}