Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 913 insertions, 0 deletions

diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
new file mode 100644
index 000000000..4f0152b11
--- /dev/null
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -0,0 +1,913 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/* -----------------------------------------------------------------------
+ *
+ *   Copyright 2011 Intel Corporation; author Matt Fleming
+ *
+ * ----------------------------------------------------------------------- */
+
+#include <linux/efi.h>
+#include <linux/pci.h>
+#include <linux/stddef.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;
+const efi_dxe_services_table_t *efi_dxe_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	= 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 void
+adjust_memory_range_protection(unsigned long start, unsigned long size)
+{
+	efi_status_t status;
+	efi_gcd_memory_space_desc_t desc;
+	unsigned long end, next;
+	unsigned long rounded_start, rounded_end;
+	unsigned long unprotect_start, unprotect_size;
+
+	if (efi_dxe_table == NULL)
+		return;
+
+	rounded_start = rounddown(start, EFI_PAGE_SIZE);
+	rounded_end = roundup(start + size, EFI_PAGE_SIZE);
+
+	/*
+	 * Don't modify memory region attributes, they are
+	 * already suitable, to lower the possibility to
+	 * encounter firmware bugs.
+	 */
+
+	for (end = start + size; start < end; start = next) {
+
+		status = efi_dxe_call(get_memory_space_descriptor, start, &desc);
+
+		if (status != EFI_SUCCESS)
+			return;
+
+		next = desc.base_address + desc.length;
+
+		/*
+		 * Only system memory is suitable for trampoline/kernel image placement,
+		 * so only this type of memory needs its attributes to be modified.
+		 */
+
+		if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory ||
+		    (desc.attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0)
+			continue;
+
+		unprotect_start = max(rounded_start, (unsigned long)desc.base_address);
+		unprotect_size = min(rounded_end, next) - unprotect_start;
+
+		status = efi_dxe_call(set_memory_space_attributes,
+				      unprotect_start, unprotect_size,
+				      EFI_MEMORY_WB);
+
+		if (status != EFI_SUCCESS) {
+			efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n",
+				 unprotect_start,
+				 unprotect_start + unprotect_size,
+				 status);
+		}
+	}
+}
+
+/*
+ * Trampoline takes 2 pages and can be loaded in first megabyte of memory
+ * with its end placed between 128k and 640k where BIOS might start.
+ * (see arch/x86/boot/compressed/pgtable_64.c)
+ *
+ * We cannot find exact trampoline placement since memory map
+ * can be modified by UEFI, and it can alter the computed address.
+ */
+
+#define TRAMPOLINE_PLACEMENT_BASE ((128 - 8)*1024)
+#define TRAMPOLINE_PLACEMENT_SIZE (640*1024 - (128 - 8)*1024)
+
+void startup_32(struct boot_params *boot_params);
+
+static void
+setup_memory_protection(unsigned long image_base, unsigned long image_size)
+{
+	/*
+	 * Allow execution of possible trampoline used
+	 * for switching between 4- and 5-level page tables
+	 * and relocated kernel image.
+	 */
+
+	adjust_memory_range_protection(TRAMPOLINE_PLACEMENT_BASE,
+				       TRAMPOLINE_PLACEMENT_SIZE);
+
+#ifdef CONFIG_64BIT
+	if (image_base != (unsigned long)startup_32)
+		adjust_memory_range_protection(image_base, image_size);
+#else
+	/*
+	 * Clear protection flags on a whole range of possible
+	 * addresses used for KASLR. We don't need to do that
+	 * on x86_64, since KASLR/extraction is performed after
+	 * dedicated identity page tables are built and we only
+	 * need to remove possible protection on relocated image
+	 * itself disregarding further relocations.
+	 */
+	adjust_memory_range_protection(LOAD_PHYSICAL_ADDR,
+				       KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR);
+#endif
+}
+
+static const efi_char16_t apple[] = L"Apple";
+
+static void setup_quirks(struct boot_params *boot_params,
+			 unsigned long image_base,
+			 unsigned long image_size)
+{
+	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);
+	}
+
+	if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES))
+		setup_memory_protection(image_base, image_size);
+}
+
+/*
+ * 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 __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;
+
+	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 setup header from the second sector to boot_params */
+	memcpy(&hdr->jump, image_base + 512,
+	       sizeof(struct setup_header) - offsetof(struct setup_header, jump));
+
+	/*
+	 * 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;
+
+	/*
+	 * Disregard any setup data that was provided by the bootloader:
+	 * setup_data could be pointing anywhere, and we have no way of
+	 * authenticating or validating the payload.
+	 */
+	hdr->setup_data = 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)
+{
+	struct setup_data *e820ext = NULL;
+	__u32 e820ext_size = 0;
+	efi_status_t status;
+	struct exit_boot_struct priv;
+
+	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, &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.
+ */
+asmlinkage 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;
+	const struct linux_efi_initrd *initrd = NULL;
+	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);
+
+	efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID);
+	if (efi_dxe_table &&
+	    efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) {
+		efi_warn("Ignoring DXE services table: invalid signature\n");
+		efi_dxe_table = NULL;
+	}
+
+	/*
+	 * 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)) {
+		extern char _bss[];
+
+		status = efi_relocate_kernel(&bzimage_addr,
+					     (unsigned long)_bss - bzimage_addr,
+					     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.
+	 */
+	status = efi_load_initrd(image, hdr->initrd_addr_max, ULONG_MAX,
+				 &initrd);
+	if (status != EFI_SUCCESS)
+		goto fail;
+	if (initrd && initrd->size > 0) {
+		efi_set_u64_split(initrd->base, &hdr->ramdisk_image,
+				  &boot_params->ext_ramdisk_image);
+		efi_set_u64_split(initrd->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, bzimage_addr, buffer_end - buffer_start);
+
+	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);
+}