Merge branch 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull EFI updates from Ingo Molnar:
 "The EFI changes in this cycle are much larger than usual, for two
  (positive) reasons:

   - The GRUB project is showing signs of life again, resulting in the
     introduction of the generic Linux/UEFI boot protocol, instead of
     x86 specific hacks which are increasingly difficult to maintain.
     There's hope that all future extensions will now go through that
     boot protocol.

   - Preparatory work for RISC-V EFI support.

  The main changes are:

   - Boot time GDT handling changes

   - Simplify handling of EFI properties table on arm64

   - Generic EFI stub cleanups, to improve command line handling, file
     I/O, memory allocation, etc.

   - Introduce a generic initrd loading method based on calling back
     into the firmware, instead of relying on the x86 EFI handover
     protocol or device tree.

   - Introduce a mixed mode boot method that does not rely on the x86
     EFI handover protocol either, and could potentially be adopted by
     other architectures (if another one ever surfaces where one
     execution mode is a superset of another)

   - Clean up the contents of 'struct efi', and move out everything that
     doesn't need to be stored there.

   - Incorporate support for UEFI spec v2.8A changes that permit
     firmware implementations to return EFI_UNSUPPORTED from UEFI
     runtime services at OS runtime, and expose a mask of which ones are
     supported or unsupported via a configuration table.

   - Partial fix for the lack of by-VA cache maintenance in the
     decompressor on 32-bit ARM.

   - Changes to load device firmware from EFI boot service memory
     regions

   - Various documentation updates and minor code cleanups and fixes"

* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
  efi/libstub/arm: Fix spurious message that an initrd was loaded
  efi/libstub/arm64: Avoid image_base value from efi_loaded_image
  partitions/efi: Fix partition name parsing in GUID partition entry
  efi/x86: Fix cast of image argument
  efi/libstub/x86: Use ULONG_MAX as upper bound for all allocations
  efi: Fix a mistype in comments mentioning efivar_entry_iter_begin()
  efi/libstub: Avoid linking libstub/lib-ksyms.o into vmlinux
  efi/x86: Preserve %ebx correctly in efi_set_virtual_address_map()
  efi/x86: Ignore the memory attributes table on i386
  efi/x86: Don't relocate the kernel unless necessary
  efi/x86: Remove extra headroom for setup block
  efi/x86: Add kernel preferred address to PE header
  efi/x86: Decompress at start of PE image load address
  x86/boot/compressed/32: Save the output address instead of recalculating it
  efi/libstub/x86: Deal with exit() boot service returning
  x86/boot: Use unsigned comparison for addresses
  efi/x86: Avoid using code32_start
  efi/x86: Make efi32_pe_entry() more readable
  efi/x86: Respect 32-bit ABI in efi32_pe_entry()
  efi/x86: Annotate the LOADED_IMAGE_PROTOCOL_GUID with SYM_DATA
  ...

1 files changed, 837 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 000000000000..8d3a707789de
--- /dev/null
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -0,0 +1,837 @@
+// 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)
+
+static efi_system_table_t *sys_table;
+extern const bool efi_is64;
+extern u32 image_offset;
+
+__pure efi_system_table_t *efi_system_table(void)
+{
+	return sys_table;
+}
+
+__attribute_const__ bool efi_is_64bit(void)
+{
+	if (IS_ENABLED(CONFIG_EFI_MIXED))
+		return efi_is64;
+	return IS_ENABLED(CONFIG_X86_64);
+}
+
+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_printk("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_printk("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_printk("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_printk("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_printk("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_printk("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;
+	efi_loaded_image_t *image;
+	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;
+
+	sys_table = sys_table_arg;
+
+	/* Check if we were booted by the EFI firmware */
+	if (sys_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_printk("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;
+
+	hdr = &((struct boot_params *)image_base)->hdr;
+
+	status = efi_allocate_pages(0x4000, (unsigned long *)&boot_params, ULONG_MAX);
+	if (status != EFI_SUCCESS) {
+		efi_printk("Failed to allocate lowmem for boot params\n");
+		efi_exit(handle, status);
+	}
+
+	memset(boot_params, 0x0, 0x4000);
+
+	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, ULONG_MAX);
+	if (!cmdline_ptr)
+		goto fail;
+
+	hdr->cmd_line_ptr = (unsigned long)cmdline_ptr;
+	/* Fill in upper bits of command line address, NOP on 32 bit  */
+	boot_params->ext_cmd_line_ptr = (u64)(unsigned long)cmdline_ptr >> 32;
+
+	hdr->ramdisk_image = 0;
+	hdr->ramdisk_size = 0;
+
+	if (efi_is_native()) {
+		status = efi_parse_options(cmdline_ptr);
+		if (status != EFI_SUCCESS)
+			goto fail2;
+
+		if (!noinitrd()) {
+			status = efi_load_initrd(image, &ramdisk_addr,
+						 &ramdisk_size,
+						 hdr->initrd_addr_max,
+						 ULONG_MAX);
+			if (status != EFI_SUCCESS)
+				goto fail2;
+			hdr->ramdisk_image = ramdisk_addr & 0xffffffff;
+			hdr->ramdisk_size  = ramdisk_size & 0xffffffff;
+			boot_params->ext_ramdisk_image = (u64)ramdisk_addr >> 32;
+			boot_params->ext_ramdisk_size  = (u64)ramdisk_size >> 32;
+		}
+	}
+
+	efi_stub_entry(handle, sys_table, boot_params);
+	/* not reached */
+
+fail2:
+	efi_free(options_size, (unsigned long)cmdline_ptr);
+fail:
+	efi_free(0x4000, (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, buff_size;
+	struct efi_boot_memmap boot_map;
+	efi_memory_desc_t *map;
+	efi_status_t status;
+	__u32 nr_desc;
+
+	boot_map.map		= &map;
+	boot_map.map_size	= &map_size;
+	boot_map.desc_size	= &desc_size;
+	boot_map.desc_ver	= NULL;
+	boot_map.key_ptr	= NULL;
+	boot_map.buff_size	= &buff_size;
+
+	status = efi_get_memory_map(&boot_map);
+	if (status != EFI_SUCCESS)
+		return status;
+
+	nr_desc = buff_size / desc_size;
+
+	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));
+
+	p->efi->efi_systab		= (unsigned long)efi_system_table();
+	p->efi->efi_memdesc_size	= *map->desc_size;
+	p->efi->efi_memdesc_version	= *map->desc_ver;
+	p->efi->efi_memmap		= (unsigned long)*map->map;
+	p->efi->efi_memmap_size		= *map->map_size;
+
+#ifdef CONFIG_X86_64
+	p->efi->efi_systab_hi		= (unsigned long)efi_system_table() >> 32;
+	p->efi->efi_memmap_hi		= (unsigned long)*map->map >> 32;
+#endif
+
+	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;
+	unsigned long cmdline_paddr;
+
+	sys_table = sys_table_arg;
+
+	/* Check if we were booted by the EFI firmware */
+	if (sys_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. we weren't loaded by
+	 * LoadImage, but we are not aligned correctly.
+	 */
+
+	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 && !IS_ALIGNED(bzimage_addr,
+					      hdr->kernel_alignment))) {
+		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_printk("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;
+	}
+
+	/*
+	 * efi_pe_entry() may have been called before efi_main(), in which
+	 * case this is the second time we parse the cmdline. This is ok,
+	 * parsing the cmdline multiple times does not have side-effects.
+	 */
+	cmdline_paddr = ((u64)hdr->cmd_line_ptr |
+			 ((u64)boot_params->ext_cmd_line_ptr << 32));
+	efi_parse_options((char *)cmdline_paddr);
+
+	/*
+	 * At this point, an initrd may already have been loaded, either by
+	 * the bootloader and passed via bootparams, or loaded from a initrd=
+	 * command line option by efi_pe_entry() above. In either case, we
+	 * permit an initrd loaded from the LINUX_EFI_INITRD_MEDIA_GUID device
+	 * path to supersede it.
+	 */
+	if (!noinitrd()) {
+		unsigned long addr, size;
+
+		status = efi_load_initrd_dev_path(&addr, &size, ULONG_MAX);
+		if (status == EFI_SUCCESS) {
+			hdr->ramdisk_image		= (u32)addr;
+			hdr->ramdisk_size 		= (u32)size;
+			boot_params->ext_ramdisk_image	= (u64)addr >> 32;
+			boot_params->ext_ramdisk_size 	= (u64)size >> 32;
+		} else if (status != EFI_NOT_FOUND) {
+			efi_printk("efi_load_initrd_dev_path() failed!\n");
+			goto fail;
+		}
+	}
+
+	/*
+	 * 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_printk("exit_boot() failed!\n");
+		goto fail;
+	}
+
+	return bzimage_addr;
+fail:
+	efi_printk("efi_main() failed!\n");
+
+	efi_exit(handle, status);
+}