drivers/firmware/efi/libstub/x86-stub.c - linux/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only

 /* -----------------------------------------------------------------------
  *
  *   Copyright 2011 Intel Corporation; author Matt Fleming
  *
  * ----------------------------------------------------------------------- */

 #include <linux/efi.h>
 #include <linux/pci.h>

 #include <asm/efi.h>
 #include <asm/e820/types.h>
 #include <asm/setup.h>
 #include <asm/desc.h>
 #include <asm/boot.h>

 #include "efistub.h"

 /* Maximum physical address for 64-bit kernel with 4-level paging */
 #define MAXMEM_X86_64_4LEVEL (1ull << 46)

 const efi_system_table_t *efi_system_table;
 extern u32 image_offset;
 static efi_loaded_image_t *image = NULL;

 static efi_status_t
 preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
 {
 	struct pci_setup_rom *rom = NULL;
 	efi_status_t status;
 	unsigned long size;
 	uint64_t romsize;
 	void *romimage;

 	/*
 	 * Some firmware images contain EFI function pointers at the place where
 	 * the romimage and romsize fields are supposed to be. Typically the EFI
 	 * code is mapped at high addresses, translating to an unrealistically
 	 * large romsize. The UEFI spec limits the size of option ROMs to 16
 	 * MiB so we reject any ROMs over 16 MiB in size to catch this.
 	 */
 	romimage = efi_table_attr(pci, romimage);
 	romsize = efi_table_attr(pci, romsize);
 	if (!romimage || !romsize || romsize > SZ_16M)
 		return EFI_INVALID_PARAMETER;

 	size = romsize + sizeof(*rom);

 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 			     (void **)&rom);
 	if (status != EFI_SUCCESS) {
 		efi_err("Failed to allocate memory for 'rom'\n");
 		return status;
 	}

 	memset(rom, 0, sizeof(*rom));

 	rom->data.type	= SETUP_PCI;
 	rom->data.len	= size - sizeof(struct setup_data);
 	rom->data.next	= 0;
 	rom->pcilen	= pci->romsize;
 	*__rom = rom;

 	status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
 				PCI_VENDOR_ID, 1, &rom->vendor);

 	if (status != EFI_SUCCESS) {
 		efi_err("Failed to read rom->vendor\n");
 		goto free_struct;
 	}

 	status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
 				PCI_DEVICE_ID, 1, &rom->devid);

 	if (status != EFI_SUCCESS) {
 		efi_err("Failed to read rom->devid\n");
 		goto free_struct;
 	}

 	status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus,
 				&rom->device, &rom->function);

 	if (status != EFI_SUCCESS)
 		goto free_struct;

 	memcpy(rom->romdata, romimage, romsize);
 	return status;

 free_struct:
 	efi_bs_call(free_pool, rom);
 	return status;
 }

 /*
  * There's no way to return an informative status from this function,
  * because any analysis (and printing of error messages) needs to be
  * done directly at the EFI function call-site.
  *
  * For example, EFI_INVALID_PARAMETER could indicate a bug or maybe we
  * just didn't find any PCI devices, but there's no way to tell outside
  * the context of the call.
  */
 static void setup_efi_pci(struct boot_params *params)
 {
 	efi_status_t status;
 	void **pci_handle = NULL;
 	efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID;
 	unsigned long size = 0;
 	struct setup_data *data;
 	efi_handle_t h;
 	int i;

 	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 			     &pci_proto, NULL, &size, pci_handle);

 	if (status == EFI_BUFFER_TOO_SMALL) {
 		status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 				     (void **)&pci_handle);

 		if (status != EFI_SUCCESS) {
 			efi_err("Failed to allocate memory for 'pci_handle'\n");
 			return;
 		}

 		status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 				     &pci_proto, NULL, &size, pci_handle);
 	}

 	if (status != EFI_SUCCESS)
 		goto free_handle;

 	data = (struct setup_data *)(unsigned long)params->hdr.setup_data;

 	while (data && data->next)
 		data = (struct setup_data *)(unsigned long)data->next;

 	for_each_efi_handle(h, pci_handle, size, i) {
 		efi_pci_io_protocol_t *pci = NULL;
 		struct pci_setup_rom *rom;

 		status = efi_bs_call(handle_protocol, h, &pci_proto,
 				     (void **)&pci);
 		if (status != EFI_SUCCESS || !pci)
 			continue;

 		status = preserve_pci_rom_image(pci, &rom);
 		if (status != EFI_SUCCESS)
 			continue;

 		if (data)
 			data->next = (unsigned long)rom;
 		else
 			params->hdr.setup_data = (unsigned long)rom;

 		data = (struct setup_data *)rom;
 	}

 free_handle:
 	efi_bs_call(free_pool, pci_handle);
 }

 static void retrieve_apple_device_properties(struct boot_params *boot_params)
 {
 	efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID;
 	struct setup_data *data, *new;
 	efi_status_t status;
 	u32 size = 0;
 	apple_properties_protocol_t *p;

 	status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&p);
 	if (status != EFI_SUCCESS)
 		return;

 	if (efi_table_attr(p, version) != 0x10000) {
 		efi_err("Unsupported properties proto version\n");
 		return;
 	}

 	efi_call_proto(p, get_all, NULL, &size);
 	if (!size)
 		return;

 	do {
 		status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
 				     size + sizeof(struct setup_data),
 				     (void **)&new);
 		if (status != EFI_SUCCESS) {
 			efi_err("Failed to allocate memory for 'properties'\n");
 			return;
 		}

 		status = efi_call_proto(p, get_all, new->data, &size);

 		if (status == EFI_BUFFER_TOO_SMALL)
 			efi_bs_call(free_pool, new);
 	} while (status == EFI_BUFFER_TOO_SMALL);

 	new->type = SETUP_APPLE_PROPERTIES;
 	new->len  = size;
 	new->next = 0;

 	data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
 	if (!data) {
 		boot_params->hdr.setup_data = (unsigned long)new;
 	} else {
 		while (data->next)
 			data = (struct setup_data *)(unsigned long)data->next;
 		data->next = (unsigned long)new;
 	}
 }

 static const efi_char16_t apple[] = L"Apple";

 static void setup_quirks(struct boot_params *boot_params)
 {
 	efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long)
 		efi_table_attr(efi_system_table, fw_vendor);

 	if (!memcmp(fw_vendor, apple, sizeof(apple))) {
 		if (IS_ENABLED(CONFIG_APPLE_PROPERTIES))
 			retrieve_apple_device_properties(boot_params);
 	}
 }

 /*
  * See if we have Universal Graphics Adapter (UGA) protocol
  */
 static efi_status_t
 setup_uga(struct screen_info *si, efi_guid_t *uga_proto, unsigned long size)
 {
 	efi_status_t status;
 	u32 width, height;
 	void **uga_handle = NULL;
 	efi_uga_draw_protocol_t *uga = NULL, *first_uga;
 	efi_handle_t handle;
 	int i;

 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 			     (void **)&uga_handle);
 	if (status != EFI_SUCCESS)
 		return status;

 	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 			     uga_proto, NULL, &size, uga_handle);
 	if (status != EFI_SUCCESS)
 		goto free_handle;

 	height = 0;
 	width = 0;

 	first_uga = NULL;
 	for_each_efi_handle(handle, uga_handle, size, i) {
 		efi_guid_t pciio_proto = EFI_PCI_IO_PROTOCOL_GUID;
 		u32 w, h, depth, refresh;
 		void *pciio;

 		status = efi_bs_call(handle_protocol, handle, uga_proto,
 				     (void **)&uga);
 		if (status != EFI_SUCCESS)
 			continue;

 		pciio = NULL;
 		efi_bs_call(handle_protocol, handle, &pciio_proto, &pciio);

 		status = efi_call_proto(uga, get_mode, &w, &h, &depth, &refresh);
 		if (status == EFI_SUCCESS && (!first_uga || pciio)) {
 			width = w;
 			height = h;

 			/*
 			 * Once we've found a UGA supporting PCIIO,
 			 * don't bother looking any further.
 			 */
 			if (pciio)
 				break;

 			first_uga = uga;
 		}
 	}

 	if (!width && !height)
 		goto free_handle;

 	/* EFI framebuffer */
 	si->orig_video_isVGA	= VIDEO_TYPE_EFI;

 	si->lfb_depth		= 32;
 	si->lfb_width		= width;
 	si->lfb_height		= height;

 	si->red_size		= 8;
 	si->red_pos		= 16;
 	si->green_size		= 8;
 	si->green_pos		= 8;
 	si->blue_size		= 8;
 	si->blue_pos		= 0;
 	si->rsvd_size		= 8;
 	si->rsvd_pos		= 24;

 free_handle:
 	efi_bs_call(free_pool, uga_handle);

 	return status;
 }

 static void setup_graphics(struct boot_params *boot_params)
 {
 	efi_guid_t graphics_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
 	struct screen_info *si;
 	efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID;
 	efi_status_t status;
 	unsigned long size;
 	void **gop_handle = NULL;
 	void **uga_handle = NULL;

 	si = &boot_params->screen_info;
 	memset(si, 0, sizeof(*si));

 	size = 0;
 	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 			     &graphics_proto, NULL, &size, gop_handle);
 	if (status == EFI_BUFFER_TOO_SMALL)
 		status = efi_setup_gop(si, &graphics_proto, size);

 	if (status != EFI_SUCCESS) {
 		size = 0;
 		status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
 				     &uga_proto, NULL, &size, uga_handle);
 		if (status == EFI_BUFFER_TOO_SMALL)
 			setup_uga(si, &uga_proto, size);
 	}
 }


 static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status)
 {
 	efi_bs_call(exit, handle, status, 0, NULL);
 	for(;;)
 		asm("hlt");
 }

 void startup_32(struct boot_params *boot_params);

 void __noreturn efi_stub_entry(efi_handle_t handle,
 			       efi_system_table_t *sys_table_arg,
 			       struct boot_params *boot_params);

 /*
  * Because the x86 boot code expects to be passed a boot_params we
  * need to create one ourselves (usually the bootloader would create
  * one for us).
  */
 efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
 				   efi_system_table_t *sys_table_arg)
 {
 	struct boot_params *boot_params;
 	struct setup_header *hdr;
 	void *image_base;
 	efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
 	int options_size = 0;
 	efi_status_t status;
 	char *cmdline_ptr;
 	unsigned long ramdisk_addr;
 	unsigned long ramdisk_size;

 	efi_system_table = sys_table_arg;

 	/* Check if we were booted by the EFI firmware */
 	if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 		efi_exit(handle, EFI_INVALID_PARAMETER);

 	status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image);
 	if (status != EFI_SUCCESS) {
 		efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
 		efi_exit(handle, status);
 	}

 	image_base = efi_table_attr(image, image_base);
 	image_offset = (void *)startup_32 - image_base;

 	status = efi_allocate_pages(sizeof(struct boot_params),
 				    (unsigned long *)&boot_params, ULONG_MAX);
 	if (status != EFI_SUCCESS) {
 		efi_err("Failed to allocate lowmem for boot params\n");
 		efi_exit(handle, status);
 	}

 	memset(boot_params, 0x0, sizeof(struct boot_params));

 	hdr = &boot_params->hdr;

 	/* Copy the second sector to boot_params */
 	memcpy(&hdr->jump, image_base + 512, 512);

 	/*
 	 * Fill out some of the header fields ourselves because the
 	 * EFI firmware loader doesn't load the first sector.
 	 */
 	hdr->root_flags	= 1;
 	hdr->vid_mode	= 0xffff;
 	hdr->boot_flag	= 0xAA55;

 	hdr->type_of_loader = 0x21;

 	/* Convert unicode cmdline to ascii */
 	cmdline_ptr = efi_convert_cmdline(image, &options_size);
 	if (!cmdline_ptr)
 		goto fail;

 	efi_set_u64_split((unsigned long)cmdline_ptr,
 			  &hdr->cmd_line_ptr, &boot_params->ext_cmd_line_ptr);

 	hdr->ramdisk_image = 0;
 	hdr->ramdisk_size = 0;

 	efi_stub_entry(handle, sys_table_arg, boot_params);
 	/* not reached */

 fail:
 	efi_free(sizeof(struct boot_params), (unsigned long)boot_params);

 	efi_exit(handle, status);
 }

 static void add_e820ext(struct boot_params *params,
 			struct setup_data *e820ext, u32 nr_entries)
 {
 	struct setup_data *data;

 	e820ext->type = SETUP_E820_EXT;
 	e820ext->len  = nr_entries * sizeof(struct boot_e820_entry);
 	e820ext->next = 0;

 	data = (struct setup_data *)(unsigned long)params->hdr.setup_data;

 	while (data && data->next)
 		data = (struct setup_data *)(unsigned long)data->next;

 	if (data)
 		data->next = (unsigned long)e820ext;
 	else
 		params->hdr.setup_data = (unsigned long)e820ext;
 }

 static efi_status_t
 setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_size)
 {
 	struct boot_e820_entry *entry = params->e820_table;
 	struct efi_info *efi = &params->efi_info;
 	struct boot_e820_entry *prev = NULL;
 	u32 nr_entries;
 	u32 nr_desc;
 	int i;

 	nr_entries = 0;
 	nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;

 	for (i = 0; i < nr_desc; i++) {
 		efi_memory_desc_t *d;
 		unsigned int e820_type = 0;
 		unsigned long m = efi->efi_memmap;

 #ifdef CONFIG_X86_64
 		m |= (u64)efi->efi_memmap_hi << 32;
 #endif

 		d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i);
 		switch (d->type) {
 		case EFI_RESERVED_TYPE:
 		case EFI_RUNTIME_SERVICES_CODE:
 		case EFI_RUNTIME_SERVICES_DATA:
 		case EFI_MEMORY_MAPPED_IO:
 		case EFI_MEMORY_MAPPED_IO_PORT_SPACE:
 		case EFI_PAL_CODE:
 			e820_type = E820_TYPE_RESERVED;
 			break;

 		case EFI_UNUSABLE_MEMORY:
 			e820_type = E820_TYPE_UNUSABLE;
 			break;

 		case EFI_ACPI_RECLAIM_MEMORY:
 			e820_type = E820_TYPE_ACPI;
 			break;

 		case EFI_LOADER_CODE:
 		case EFI_LOADER_DATA:
 		case EFI_BOOT_SERVICES_CODE:
 		case EFI_BOOT_SERVICES_DATA:
 		case EFI_CONVENTIONAL_MEMORY:
 			if (efi_soft_reserve_enabled() &&
 			    (d->attribute & EFI_MEMORY_SP))
 				e820_type = E820_TYPE_SOFT_RESERVED;
 			else
 				e820_type = E820_TYPE_RAM;
 			break;

 		case EFI_ACPI_MEMORY_NVS:
 			e820_type = E820_TYPE_NVS;
 			break;

 		case EFI_PERSISTENT_MEMORY:
 			e820_type = E820_TYPE_PMEM;
 			break;

 		default:
 			continue;
 		}

 		/* Merge adjacent mappings */
 		if (prev && prev->type == e820_type &&
 		    (prev->addr + prev->size) == d->phys_addr) {
 			prev->size += d->num_pages << 12;
 			continue;
 		}

 		if (nr_entries == ARRAY_SIZE(params->e820_table)) {
 			u32 need = (nr_desc - i) * sizeof(struct e820_entry) +
 				   sizeof(struct setup_data);

 			if (!e820ext || e820ext_size < need)
 				return EFI_BUFFER_TOO_SMALL;

 			/* boot_params map full, switch to e820 extended */
 			entry = (struct boot_e820_entry *)e820ext->data;
 		}

 		entry->addr = d->phys_addr;
 		entry->size = d->num_pages << PAGE_SHIFT;
 		entry->type = e820_type;
 		prev = entry++;
 		nr_entries++;
 	}

 	if (nr_entries > ARRAY_SIZE(params->e820_table)) {
 		u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_table);

 		add_e820ext(params, e820ext, nr_e820ext);
 		nr_entries -= nr_e820ext;
 	}

 	params->e820_entries = (u8)nr_entries;

 	return EFI_SUCCESS;
 }

 static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
 				  u32 *e820ext_size)
 {
 	efi_status_t status;
 	unsigned long size;

 	size = sizeof(struct setup_data) +
 		sizeof(struct e820_entry) * nr_desc;

 	if (*e820ext) {
 		efi_bs_call(free_pool, *e820ext);
 		*e820ext = NULL;
 		*e820ext_size = 0;
 	}

 	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
 			     (void **)e820ext);
 	if (status == EFI_SUCCESS)
 		*e820ext_size = size;

 	return status;
 }

 static efi_status_t allocate_e820(struct boot_params *params,
 				  struct setup_data **e820ext,
 				  u32 *e820ext_size)
 {
 	unsigned long map_size, desc_size, map_key;
 	efi_status_t status;
 	__u32 nr_desc, desc_version;

 	/* Only need the size of the mem map and size of each mem descriptor */
 	map_size = 0;
 	status = efi_bs_call(get_memory_map, &map_size, NULL, &map_key,
 			     &desc_size, &desc_version);
 	if (status != EFI_BUFFER_TOO_SMALL)
 		return (status != EFI_SUCCESS) ? status : EFI_UNSUPPORTED;

 	nr_desc = map_size / desc_size + EFI_MMAP_NR_SLACK_SLOTS;

 	if (nr_desc > ARRAY_SIZE(params->e820_table)) {
 		u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table);

 		status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
 		if (status != EFI_SUCCESS)
 			return status;
 	}

 	return EFI_SUCCESS;
 }

 struct exit_boot_struct {
 	struct boot_params	*boot_params;
 	struct efi_info		*efi;
 };

 static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
 				   void *priv)
 {
 	const char *signature;
 	struct exit_boot_struct *p = priv;

 	signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
 				   : EFI32_LOADER_SIGNATURE;
 	memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));

 	efi_set_u64_split((unsigned long)efi_system_table,
 			  &p->efi->efi_systab, &p->efi->efi_systab_hi);
 	p->efi->efi_memdesc_size	= *map->desc_size;
 	p->efi->efi_memdesc_version	= *map->desc_ver;
 	efi_set_u64_split((unsigned long)*map->map,
 			  &p->efi->efi_memmap, &p->efi->efi_memmap_hi);
 	p->efi->efi_memmap_size		= *map->map_size;

 	return EFI_SUCCESS;
 }

 static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
 {
 	unsigned long map_sz, key, desc_size, buff_size;
 	efi_memory_desc_t *mem_map;
 	struct setup_data *e820ext = NULL;
 	__u32 e820ext_size = 0;
 	efi_status_t status;
 	__u32 desc_version;
 	struct efi_boot_memmap map;
 	struct exit_boot_struct priv;

 	map.map			= &mem_map;
 	map.map_size		= &map_sz;
 	map.desc_size		= &desc_size;
 	map.desc_ver		= &desc_version;
 	map.key_ptr		= &key;
 	map.buff_size		= &buff_size;
 	priv.boot_params	= boot_params;
 	priv.efi		= &boot_params->efi_info;

 	status = allocate_e820(boot_params, &e820ext, &e820ext_size);
 	if (status != EFI_SUCCESS)
 		return status;

 	/* Might as well exit boot services now */
 	status = efi_exit_boot_services(handle, &map, &priv, exit_boot_func);
 	if (status != EFI_SUCCESS)
 		return status;

 	/* Historic? */
 	boot_params->alt_mem_k	= 32 * 1024;

 	status = setup_e820(boot_params, e820ext, e820ext_size);
 	if (status != EFI_SUCCESS)
 		return status;

 	return EFI_SUCCESS;
 }

 /*
  * On success, we return the address of startup_32, which has potentially been
  * relocated by efi_relocate_kernel.
  * On failure, we exit to the firmware via efi_exit instead of returning.
  */
 unsigned long efi_main(efi_handle_t handle,
 			     efi_system_table_t *sys_table_arg,
 			     struct boot_params *boot_params)
 {
 	unsigned long bzimage_addr = (unsigned long)startup_32;
 	unsigned long buffer_start, buffer_end;
 	struct setup_header *hdr = &boot_params->hdr;
 	efi_status_t status;

 	efi_system_table = sys_table_arg;

 	/* Check if we were booted by the EFI firmware */
 	if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 		efi_exit(handle, EFI_INVALID_PARAMETER);

 	/*
 	 * If the kernel isn't already loaded at a suitable address,
 	 * relocate it.
 	 *
 	 * It must be loaded above LOAD_PHYSICAL_ADDR.
 	 *
 	 * The maximum address for 64-bit is 1 << 46 for 4-level paging. This
 	 * is defined as the macro MAXMEM, but unfortunately that is not a
 	 * compile-time constant if 5-level paging is configured, so we instead
 	 * define our own macro for use here.
 	 *
 	 * For 32-bit, the maximum address is complicated to figure out, for
 	 * now use KERNEL_IMAGE_SIZE, which will be 512MiB, the same as what
 	 * KASLR uses.
 	 *
 	 * Also relocate it if image_offset is zero, i.e. the kernel wasn't
 	 * loaded by LoadImage, but rather by a bootloader that called the
 	 * handover entry. The reason we must always relocate in this case is
 	 * to handle the case of systemd-boot booting a unified kernel image,
 	 * which is a PE executable that contains the bzImage and an initrd as
 	 * COFF sections. The initrd section is placed after the bzImage
 	 * without ensuring that there are at least init_size bytes available
 	 * for the bzImage, and thus the compressed kernel's startup code may
 	 * overwrite the initrd unless it is moved out of the way.
 	 */

 	buffer_start = ALIGN(bzimage_addr - image_offset,
 			     hdr->kernel_alignment);
 	buffer_end = buffer_start + hdr->init_size;

 	if ((buffer_start < LOAD_PHYSICAL_ADDR)				     ||
 	    (IS_ENABLED(CONFIG_X86_32) && buffer_end > KERNEL_IMAGE_SIZE)    ||
 	    (IS_ENABLED(CONFIG_X86_64) && buffer_end > MAXMEM_X86_64_4LEVEL) ||
 	    (image_offset == 0)) {
 		status = efi_relocate_kernel(&bzimage_addr,
 					     hdr->init_size, hdr->init_size,
 					     hdr->pref_address,
 					     hdr->kernel_alignment,
 					     LOAD_PHYSICAL_ADDR);
 		if (status != EFI_SUCCESS) {
 			efi_err("efi_relocate_kernel() failed!\n");
 			goto fail;
 		}
 		/*
 		 * Now that we've copied the kernel elsewhere, we no longer
 		 * have a set up block before startup_32(), so reset image_offset
 		 * to zero in case it was set earlier.
 		 */
 		image_offset = 0;
 	}

 #ifdef CONFIG_CMDLINE_BOOL
 	status = efi_parse_options(CONFIG_CMDLINE);
 	if (status != EFI_SUCCESS) {
 		efi_err("Failed to parse options\n");
 		goto fail;
 	}
 #endif
 	if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
 		unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
 					       ((u64)boot_params->ext_cmd_line_ptr << 32));
 		status = efi_parse_options((char *)cmdline_paddr);
 		if (status != EFI_SUCCESS) {
 			efi_err("Failed to parse options\n");
 			goto fail;
 		}
 	}

 	/*
 	 * At this point, an initrd may already have been loaded by the
 	 * bootloader and passed via bootparams. We permit an initrd loaded
 	 * from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it.
 	 *
 	 * If the device path is not present, any command-line initrd=
 	 * arguments will be processed only if image is not NULL, which will be
 	 * the case only if we were loaded via the PE entry point.
 	 */
 	if (!efi_noinitrd) {
 		unsigned long addr, size;

 		status = efi_load_initrd(image, &addr, &size,
 					 hdr->initrd_addr_max, ULONG_MAX);

 		if (status != EFI_SUCCESS) {
 			efi_err("Failed to load initrd!\n");
 			goto fail;
 		}
 		if (size > 0) {
 			efi_set_u64_split(addr, &hdr->ramdisk_image,
 					  &boot_params->ext_ramdisk_image);
 			efi_set_u64_split(size, &hdr->ramdisk_size,
 					  &boot_params->ext_ramdisk_size);
 		}
 	}

 	/*
 	 * If the boot loader gave us a value for secure_boot then we use that,
 	 * otherwise we ask the BIOS.
 	 */
 	if (boot_params->secure_boot == efi_secureboot_mode_unset)
 		boot_params->secure_boot = efi_get_secureboot();

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

 	efi_random_get_seed();

 	efi_retrieve_tpm2_eventlog();

 	setup_graphics(boot_params);

 	setup_efi_pci(boot_params);

 	setup_quirks(boot_params);

 	status = exit_boot(boot_params, handle);
 	if (status != EFI_SUCCESS) {
 		efi_err("exit_boot() failed!\n");
 		goto fail;
 	}

 	return bzimage_addr;
 fail:
 	efi_err("efi_main() failed!\n");

 	efi_exit(handle, status);
 }
	// SPDX-License-Identifier: GPL-2.0-only

	/* -----------------------------------------------------------------------
	*
	* Copyright 2011 Intel Corporation; author Matt Fleming
	*
	* ----------------------------------------------------------------------- */

	#include <linux/efi.h>
	#include <linux/pci.h>

	#include <asm/efi.h>
	#include <asm/e820/types.h>
	#include <asm/setup.h>
	#include <asm/desc.h>
	#include <asm/boot.h>

	#include "efistub.h"

	/* Maximum physical address for 64-bit kernel with 4-level paging */
	#define MAXMEM_X86_64_4LEVEL (1ull << 46)

	const efi_system_table_t *efi_system_table;
	extern u32 image_offset;
	static efi_loaded_image_t *image = NULL;

	static efi_status_t
	preserve_pci_rom_image(efi_pci_io_protocol_t pci, struct pci_setup_rom *__rom)
	{
	struct pci_setup_rom *rom = NULL;
	efi_status_t status;
	unsigned long size;
	uint64_t romsize;
	void *romimage;

	/*
	* Some firmware images contain EFI function pointers at the place where
	* the romimage and romsize fields are supposed to be. Typically the EFI
	* code is mapped at high addresses, translating to an unrealistically
	* large romsize. The UEFI spec limits the size of option ROMs to 16
	* MiB so we reject any ROMs over 16 MiB in size to catch this.
	*/
	romimage = efi_table_attr(pci, romimage);
	romsize = efi_table_attr(pci, romsize);
	if (!romimage \|\| !romsize \|\| romsize > SZ_16M)
	return EFI_INVALID_PARAMETER;

	size = romsize + sizeof(*rom);

	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
	(void **)&rom);
	if (status != EFI_SUCCESS) {
	efi_err("Failed to allocate memory for 'rom'\n");
	return status;
	}

	memset(rom, 0, sizeof(*rom));

	rom->data.type = SETUP_PCI;
	rom->data.len = size - sizeof(struct setup_data);
	rom->data.next = 0;
	rom->pcilen = pci->romsize;
	*__rom = rom;

	status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
	PCI_VENDOR_ID, 1, &rom->vendor);

	if (status != EFI_SUCCESS) {
	efi_err("Failed to read rom->vendor\n");
	goto free_struct;
	}

	status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
	PCI_DEVICE_ID, 1, &rom->devid);

	if (status != EFI_SUCCESS) {
	efi_err("Failed to read rom->devid\n");
	goto free_struct;
	}

	status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus,
	&rom->device, &rom->function);

	if (status != EFI_SUCCESS)
	goto free_struct;

	memcpy(rom->romdata, romimage, romsize);
	return status;

	free_struct:
	efi_bs_call(free_pool, rom);
	return status;
	}

	/*
	* There's no way to return an informative status from this function,
	* because any analysis (and printing of error messages) needs to be
	* done directly at the EFI function call-site.
	*
	* For example, EFI_INVALID_PARAMETER could indicate a bug or maybe we
	* just didn't find any PCI devices, but there's no way to tell outside
	* the context of the call.
	*/
	static void setup_efi_pci(struct boot_params *params)
	{
	efi_status_t status;
	void **pci_handle = NULL;
	efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID;
	unsigned long size = 0;
	struct setup_data *data;
	efi_handle_t h;
	int i;

	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
	&pci_proto, NULL, &size, pci_handle);

	if (status == EFI_BUFFER_TOO_SMALL) {
	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
	(void **)&pci_handle);

	if (status != EFI_SUCCESS) {
	efi_err("Failed to allocate memory for 'pci_handle'\n");
	return;
	}

	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
	&pci_proto, NULL, &size, pci_handle);
	}

	if (status != EFI_SUCCESS)
	goto free_handle;

	data = (struct setup_data *)(unsigned long)params->hdr.setup_data;

	while (data && data->next)
	data = (struct setup_data *)(unsigned long)data->next;

	for_each_efi_handle(h, pci_handle, size, i) {
	efi_pci_io_protocol_t *pci = NULL;
	struct pci_setup_rom *rom;

	status = efi_bs_call(handle_protocol, h, &pci_proto,
	(void **)&pci);
	if (status != EFI_SUCCESS \|\| !pci)
	continue;

	status = preserve_pci_rom_image(pci, &rom);
	if (status != EFI_SUCCESS)
	continue;

	if (data)
	data->next = (unsigned long)rom;
	else
	params->hdr.setup_data = (unsigned long)rom;

	data = (struct setup_data *)rom;
	}

	free_handle:
	efi_bs_call(free_pool, pci_handle);
	}

	static void retrieve_apple_device_properties(struct boot_params *boot_params)
	{
	efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID;
	struct setup_data data, new;
	efi_status_t status;
	u32 size = 0;
	apple_properties_protocol_t *p;

	status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&p);
	if (status != EFI_SUCCESS)
	return;

	if (efi_table_attr(p, version) != 0x10000) {
	efi_err("Unsupported properties proto version\n");
	return;
	}

	efi_call_proto(p, get_all, NULL, &size);
	if (!size)
	return;

	do {
	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
	size + sizeof(struct setup_data),
	(void **)&new);
	if (status != EFI_SUCCESS) {
	efi_err("Failed to allocate memory for 'properties'\n");
	return;
	}

	status = efi_call_proto(p, get_all, new->data, &size);

	if (status == EFI_BUFFER_TOO_SMALL)
	efi_bs_call(free_pool, new);
	} while (status == EFI_BUFFER_TOO_SMALL);

	new->type = SETUP_APPLE_PROPERTIES;
	new->len = size;
	new->next = 0;

	data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
	if (!data) {
	boot_params->hdr.setup_data = (unsigned long)new;
	} else {
	while (data->next)
	data = (struct setup_data *)(unsigned long)data->next;
	data->next = (unsigned long)new;
	}
	}

	static const efi_char16_t apple[] = L"Apple";

	static void setup_quirks(struct boot_params *boot_params)
	{
	efi_char16_t fw_vendor = (efi_char16_t )(unsigned long)
	efi_table_attr(efi_system_table, fw_vendor);

	if (!memcmp(fw_vendor, apple, sizeof(apple))) {
	if (IS_ENABLED(CONFIG_APPLE_PROPERTIES))
	retrieve_apple_device_properties(boot_params);
	}
	}

	/*
	* See if we have Universal Graphics Adapter (UGA) protocol
	*/
	static efi_status_t
	setup_uga(struct screen_info si, efi_guid_t uga_proto, unsigned long size)
	{
	efi_status_t status;
	u32 width, height;
	void **uga_handle = NULL;
	efi_uga_draw_protocol_t uga = NULL, first_uga;
	efi_handle_t handle;
	int i;

	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
	(void **)&uga_handle);
	if (status != EFI_SUCCESS)
	return status;

	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
	uga_proto, NULL, &size, uga_handle);
	if (status != EFI_SUCCESS)
	goto free_handle;

	height = 0;
	width = 0;

	first_uga = NULL;
	for_each_efi_handle(handle, uga_handle, size, i) {
	efi_guid_t pciio_proto = EFI_PCI_IO_PROTOCOL_GUID;
	u32 w, h, depth, refresh;
	void *pciio;

	status = efi_bs_call(handle_protocol, handle, uga_proto,
	(void **)&uga);
	if (status != EFI_SUCCESS)
	continue;

	pciio = NULL;
	efi_bs_call(handle_protocol, handle, &pciio_proto, &pciio);

	status = efi_call_proto(uga, get_mode, &w, &h, &depth, &refresh);
	if (status == EFI_SUCCESS && (!first_uga \|\| pciio)) {
	width = w;
	height = h;

	/*
	* Once we've found a UGA supporting PCIIO,
	* don't bother looking any further.
	*/
	if (pciio)
	break;

	first_uga = uga;
	}
	}

	if (!width && !height)
	goto free_handle;

	/* EFI framebuffer */
	si->orig_video_isVGA = VIDEO_TYPE_EFI;

	si->lfb_depth = 32;
	si->lfb_width = width;
	si->lfb_height = height;

	si->red_size = 8;
	si->red_pos = 16;
	si->green_size = 8;
	si->green_pos = 8;
	si->blue_size = 8;
	si->blue_pos = 0;
	si->rsvd_size = 8;
	si->rsvd_pos = 24;

	free_handle:
	efi_bs_call(free_pool, uga_handle);

	return status;
	}

	static void setup_graphics(struct boot_params *boot_params)
	{
	efi_guid_t graphics_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
	struct screen_info *si;
	efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID;
	efi_status_t status;
	unsigned long size;
	void **gop_handle = NULL;
	void **uga_handle = NULL;

	si = &boot_params->screen_info;
	memset(si, 0, sizeof(*si));

	size = 0;
	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
	&graphics_proto, NULL, &size, gop_handle);
	if (status == EFI_BUFFER_TOO_SMALL)
	status = efi_setup_gop(si, &graphics_proto, size);

	if (status != EFI_SUCCESS) {
	size = 0;
	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
	&uga_proto, NULL, &size, uga_handle);
	if (status == EFI_BUFFER_TOO_SMALL)
	setup_uga(si, &uga_proto, size);
	}
	}


	static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status)
	{
	efi_bs_call(exit, handle, status, 0, NULL);
	for(;;)
	asm("hlt");
	}

	void startup_32(struct boot_params *boot_params);

	void __noreturn efi_stub_entry(efi_handle_t handle,
	efi_system_table_t *sys_table_arg,
	struct boot_params *boot_params);

	/*
	* Because the x86 boot code expects to be passed a boot_params we
	* need to create one ourselves (usually the bootloader would create
	* one for us).
	*/
	efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
	efi_system_table_t *sys_table_arg)
	{
	struct boot_params *boot_params;
	struct setup_header *hdr;
	void *image_base;
	efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
	int options_size = 0;
	efi_status_t status;
	char *cmdline_ptr;
	unsigned long ramdisk_addr;
	unsigned long ramdisk_size;

	efi_system_table = sys_table_arg;

	/* Check if we were booted by the EFI firmware */
	if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
	efi_exit(handle, EFI_INVALID_PARAMETER);

	status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image);
	if (status != EFI_SUCCESS) {
	efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
	efi_exit(handle, status);
	}

	image_base = efi_table_attr(image, image_base);
	image_offset = (void *)startup_32 - image_base;

	status = efi_allocate_pages(sizeof(struct boot_params),
	(unsigned long *)&boot_params, ULONG_MAX);
	if (status != EFI_SUCCESS) {
	efi_err("Failed to allocate lowmem for boot params\n");
	efi_exit(handle, status);
	}

	memset(boot_params, 0x0, sizeof(struct boot_params));

	hdr = &boot_params->hdr;

	/* Copy the second sector to boot_params */
	memcpy(&hdr->jump, image_base + 512, 512);

	/*
	* Fill out some of the header fields ourselves because the
	* EFI firmware loader doesn't load the first sector.
	*/
	hdr->root_flags = 1;
	hdr->vid_mode = 0xffff;
	hdr->boot_flag = 0xAA55;

	hdr->type_of_loader = 0x21;

	/* Convert unicode cmdline to ascii */
	cmdline_ptr = efi_convert_cmdline(image, &options_size);
	if (!cmdline_ptr)
	goto fail;

	efi_set_u64_split((unsigned long)cmdline_ptr,
	&hdr->cmd_line_ptr, &boot_params->ext_cmd_line_ptr);

	hdr->ramdisk_image = 0;
	hdr->ramdisk_size = 0;

	efi_stub_entry(handle, sys_table_arg, boot_params);
	/* not reached */

	fail:
	efi_free(sizeof(struct boot_params), (unsigned long)boot_params);

	efi_exit(handle, status);
	}

	static void add_e820ext(struct boot_params *params,
	struct setup_data *e820ext, u32 nr_entries)
	{
	struct setup_data *data;

	e820ext->type = SETUP_E820_EXT;
	e820ext->len = nr_entries * sizeof(struct boot_e820_entry);
	e820ext->next = 0;

	data = (struct setup_data *)(unsigned long)params->hdr.setup_data;

	while (data && data->next)
	data = (struct setup_data *)(unsigned long)data->next;

	if (data)
	data->next = (unsigned long)e820ext;
	else
	params->hdr.setup_data = (unsigned long)e820ext;
	}

	static efi_status_t
	setup_e820(struct boot_params params, struct setup_data e820ext, u32 e820ext_size)
	{
	struct boot_e820_entry *entry = params->e820_table;
	struct efi_info *efi = &params->efi_info;
	struct boot_e820_entry *prev = NULL;
	u32 nr_entries;
	u32 nr_desc;
	int i;

	nr_entries = 0;
	nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;

	for (i = 0; i < nr_desc; i++) {
	efi_memory_desc_t *d;
	unsigned int e820_type = 0;
	unsigned long m = efi->efi_memmap;

	#ifdef CONFIG_X86_64
	m \|= (u64)efi->efi_memmap_hi << 32;
	#endif

	d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i);
	switch (d->type) {
	case EFI_RESERVED_TYPE:
	case EFI_RUNTIME_SERVICES_CODE:
	case EFI_RUNTIME_SERVICES_DATA:
	case EFI_MEMORY_MAPPED_IO:
	case EFI_MEMORY_MAPPED_IO_PORT_SPACE:
	case EFI_PAL_CODE:
	e820_type = E820_TYPE_RESERVED;
	break;

	case EFI_UNUSABLE_MEMORY:
	e820_type = E820_TYPE_UNUSABLE;
	break;

	case EFI_ACPI_RECLAIM_MEMORY:
	e820_type = E820_TYPE_ACPI;
	break;

	case EFI_LOADER_CODE:
	case EFI_LOADER_DATA:
	case EFI_BOOT_SERVICES_CODE:
	case EFI_BOOT_SERVICES_DATA:
	case EFI_CONVENTIONAL_MEMORY:
	if (efi_soft_reserve_enabled() &&
	(d->attribute & EFI_MEMORY_SP))
	e820_type = E820_TYPE_SOFT_RESERVED;
	else
	e820_type = E820_TYPE_RAM;
	break;

	case EFI_ACPI_MEMORY_NVS:
	e820_type = E820_TYPE_NVS;
	break;

	case EFI_PERSISTENT_MEMORY:
	e820_type = E820_TYPE_PMEM;
	break;

	default:
	continue;
	}

	/* Merge adjacent mappings */
	if (prev && prev->type == e820_type &&
	(prev->addr + prev->size) == d->phys_addr) {
	prev->size += d->num_pages << 12;
	continue;
	}

	if (nr_entries == ARRAY_SIZE(params->e820_table)) {
	u32 need = (nr_desc - i) * sizeof(struct e820_entry) +
	sizeof(struct setup_data);

	if (!e820ext \|\| e820ext_size < need)
	return EFI_BUFFER_TOO_SMALL;

	/* boot_params map full, switch to e820 extended */
	entry = (struct boot_e820_entry *)e820ext->data;
	}

	entry->addr = d->phys_addr;
	entry->size = d->num_pages << PAGE_SHIFT;
	entry->type = e820_type;
	prev = entry++;
	nr_entries++;
	}

	if (nr_entries > ARRAY_SIZE(params->e820_table)) {
	u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_table);

	add_e820ext(params, e820ext, nr_e820ext);
	nr_entries -= nr_e820ext;
	}

	params->e820_entries = (u8)nr_entries;

	return EFI_SUCCESS;
	}

	static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
	u32 *e820ext_size)
	{
	efi_status_t status;
	unsigned long size;

	size = sizeof(struct setup_data) +
	sizeof(struct e820_entry) * nr_desc;

	if (*e820ext) {
	efi_bs_call(free_pool, *e820ext);
	*e820ext = NULL;
	*e820ext_size = 0;
	}

	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
	(void **)e820ext);
	if (status == EFI_SUCCESS)
	*e820ext_size = size;

	return status;
	}

	static efi_status_t allocate_e820(struct boot_params *params,
	struct setup_data **e820ext,
	u32 *e820ext_size)
	{
	unsigned long map_size, desc_size, map_key;
	efi_status_t status;
	__u32 nr_desc, desc_version;

	/* Only need the size of the mem map and size of each mem descriptor */
	map_size = 0;
	status = efi_bs_call(get_memory_map, &map_size, NULL, &map_key,
	&desc_size, &desc_version);
	if (status != EFI_BUFFER_TOO_SMALL)
	return (status != EFI_SUCCESS) ? status : EFI_UNSUPPORTED;

	nr_desc = map_size / desc_size + EFI_MMAP_NR_SLACK_SLOTS;

	if (nr_desc > ARRAY_SIZE(params->e820_table)) {
	u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table);

	status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
	if (status != EFI_SUCCESS)
	return status;
	}

	return EFI_SUCCESS;
	}

	struct exit_boot_struct {
	struct boot_params *boot_params;
	struct efi_info *efi;
	};

	static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
	void *priv)
	{
	const char *signature;
	struct exit_boot_struct *p = priv;

	signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
	: EFI32_LOADER_SIGNATURE;
	memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));

	efi_set_u64_split((unsigned long)efi_system_table,
	&p->efi->efi_systab, &p->efi->efi_systab_hi);
	p->efi->efi_memdesc_size = *map->desc_size;
	p->efi->efi_memdesc_version = *map->desc_ver;
	efi_set_u64_split((unsigned long)*map->map,
	&p->efi->efi_memmap, &p->efi->efi_memmap_hi);
	p->efi->efi_memmap_size = *map->map_size;

	return EFI_SUCCESS;
	}

	static efi_status_t exit_boot(struct boot_params boot_params, void handle)
	{
	unsigned long map_sz, key, desc_size, buff_size;
	efi_memory_desc_t *mem_map;
	struct setup_data *e820ext = NULL;
	__u32 e820ext_size = 0;
	efi_status_t status;
	__u32 desc_version;
	struct efi_boot_memmap map;
	struct exit_boot_struct priv;

	map.map = &mem_map;
	map.map_size = &map_sz;
	map.desc_size = &desc_size;
	map.desc_ver = &desc_version;
	map.key_ptr = &key;
	map.buff_size = &buff_size;
	priv.boot_params = boot_params;
	priv.efi = &boot_params->efi_info;

	status = allocate_e820(boot_params, &e820ext, &e820ext_size);
	if (status != EFI_SUCCESS)
	return status;

	/* Might as well exit boot services now */
	status = efi_exit_boot_services(handle, &map, &priv, exit_boot_func);
	if (status != EFI_SUCCESS)
	return status;

	/* Historic? */
	boot_params->alt_mem_k = 32 * 1024;

	status = setup_e820(boot_params, e820ext, e820ext_size);
	if (status != EFI_SUCCESS)
	return status;

	return EFI_SUCCESS;
	}

	/*
	* On success, we return the address of startup_32, which has potentially been
	* relocated by efi_relocate_kernel.
	* On failure, we exit to the firmware via efi_exit instead of returning.
	*/
	unsigned long efi_main(efi_handle_t handle,
	efi_system_table_t *sys_table_arg,
	struct boot_params *boot_params)
	{
	unsigned long bzimage_addr = (unsigned long)startup_32;
	unsigned long buffer_start, buffer_end;
	struct setup_header *hdr = &boot_params->hdr;
	efi_status_t status;

	efi_system_table = sys_table_arg;

	/* Check if we were booted by the EFI firmware */
	if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
	efi_exit(handle, EFI_INVALID_PARAMETER);

	/*
	* If the kernel isn't already loaded at a suitable address,
	* relocate it.
	*
	* It must be loaded above LOAD_PHYSICAL_ADDR.
	*
	* The maximum address for 64-bit is 1 << 46 for 4-level paging. This
	* is defined as the macro MAXMEM, but unfortunately that is not a
	* compile-time constant if 5-level paging is configured, so we instead
	* define our own macro for use here.
	*
	* For 32-bit, the maximum address is complicated to figure out, for
	* now use KERNEL_IMAGE_SIZE, which will be 512MiB, the same as what
	* KASLR uses.
	*
	* Also relocate it if image_offset is zero, i.e. the kernel wasn't
	* loaded by LoadImage, but rather by a bootloader that called the
	* handover entry. The reason we must always relocate in this case is
	* to handle the case of systemd-boot booting a unified kernel image,
	* which is a PE executable that contains the bzImage and an initrd as
	* COFF sections. The initrd section is placed after the bzImage
	* without ensuring that there are at least init_size bytes available
	* for the bzImage, and thus the compressed kernel's startup code may
	* overwrite the initrd unless it is moved out of the way.
	*/

	buffer_start = ALIGN(bzimage_addr - image_offset,
	hdr->kernel_alignment);
	buffer_end = buffer_start + hdr->init_size;

	if ((buffer_start < LOAD_PHYSICAL_ADDR) \|\|
	(IS_ENABLED(CONFIG_X86_32) && buffer_end > KERNEL_IMAGE_SIZE) \|\|
	(IS_ENABLED(CONFIG_X86_64) && buffer_end > MAXMEM_X86_64_4LEVEL) \|\|
	(image_offset == 0)) {
	status = efi_relocate_kernel(&bzimage_addr,
	hdr->init_size, hdr->init_size,
	hdr->pref_address,
	hdr->kernel_alignment,
	LOAD_PHYSICAL_ADDR);
	if (status != EFI_SUCCESS) {
	efi_err("efi_relocate_kernel() failed!\n");
	goto fail;
	}
	/*
	* Now that we've copied the kernel elsewhere, we no longer
	* have a set up block before startup_32(), so reset image_offset
	* to zero in case it was set earlier.
	*/
	image_offset = 0;
	}

	#ifdef CONFIG_CMDLINE_BOOL
	status = efi_parse_options(CONFIG_CMDLINE);
	if (status != EFI_SUCCESS) {
	efi_err("Failed to parse options\n");
	goto fail;
	}
	#endif
	if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
	unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr \|
	((u64)boot_params->ext_cmd_line_ptr << 32));
	status = efi_parse_options((char *)cmdline_paddr);
	if (status != EFI_SUCCESS) {
	efi_err("Failed to parse options\n");
	goto fail;
	}
	}

	/*
	* At this point, an initrd may already have been loaded by the
	* bootloader and passed via bootparams. We permit an initrd loaded
	* from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it.
	*
	* If the device path is not present, any command-line initrd=
	* arguments will be processed only if image is not NULL, which will be
	* the case only if we were loaded via the PE entry point.
	*/
	if (!efi_noinitrd) {
	unsigned long addr, size;

	status = efi_load_initrd(image, &addr, &size,
	hdr->initrd_addr_max, ULONG_MAX);

	if (status != EFI_SUCCESS) {
	efi_err("Failed to load initrd!\n");
	goto fail;
	}
	if (size > 0) {
	efi_set_u64_split(addr, &hdr->ramdisk_image,
	&boot_params->ext_ramdisk_image);
	efi_set_u64_split(size, &hdr->ramdisk_size,
	&boot_params->ext_ramdisk_size);
	}
	}

	/*
	* If the boot loader gave us a value for secure_boot then we use that,
	* otherwise we ask the BIOS.
	*/
	if (boot_params->secure_boot == efi_secureboot_mode_unset)
	boot_params->secure_boot = efi_get_secureboot();

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

	efi_random_get_seed();

	efi_retrieve_tpm2_eventlog();

	setup_graphics(boot_params);

	setup_efi_pci(boot_params);

	setup_quirks(boot_params);

	status = exit_boot(boot_params, handle);
	if (status != EFI_SUCCESS) {
	efi_err("exit_boot() failed!\n");
	goto fail;
	}

	return bzimage_addr;
	fail:
	efi_err("efi_main() failed!\n");

	efi_exit(handle, status);
	}