linux_dsm_epyc7002/drivers/firmware/efi/libstub/x86-stub.c
Ard Biesheuvel 17054f492d efi/x86: Implement mixed mode boot without the handover protocol
Add support for booting 64-bit x86 kernels from 32-bit firmware running
on 64-bit capable CPUs without requiring the bootloader to implement
the EFI handover protocol or allocate the setup block, etc etc, all of
which can be done by the stub itself, using code that already exists.

Instead, create an ordinary EFI application entrypoint but implemented
in 32-bit code [so that it can be invoked by 32-bit firmware], and stash
the address of this 32-bit entrypoint in the .compat section where the
bootloader can find it.

Note that we use the setup block embedded in the binary to go through
startup_32(), but it gets reallocated and copied in efi_pe_entry(),
using the same code that runs when the x86 kernel is booted in EFI
mode from native firmware. This requires the loaded image protocol to
be installed on the kernel image's EFI handle, and point to the kernel
image itself and not to its loader. This, in turn, requires the
bootloader to use the LoadImage() boot service to load the 64-bit
image from 32-bit firmware, which is in fact supported by firmware
based on EDK2. (Only StartImage() will fail, and instead, the newly
added entrypoint needs to be invoked)

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23 21:59:42 +01:00

808 lines
20 KiB
C

// 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"
static efi_system_table_t *sys_table;
extern const bool efi_is64;
__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);
unreachable();
}
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;
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;
bool above4g;
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);
}
hdr = &((struct boot_params *)efi_table_attr(image, image_base))->hdr;
above4g = hdr->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G;
status = efi_allocate_pages(0x4000, (unsigned long *)&boot_params,
above4g ? ULONG_MAX : UINT_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, efi_table_attr(image, 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,
above4g ? ULONG_MAX : UINT_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,
above4g ? ULONG_MAX
: hdr->initrd_addr_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 a pointer to a boot_params structure, and NULL
* on failure.
*/
struct boot_params *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;
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 the preferred load
* address, relocate it.
*/
if (bzimage_addr != hdr->pref_address) {
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;
}
}
hdr->code32_start = (u32)bzimage_addr;
/*
* 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;
unsigned long max_addr = hdr->initrd_addr_max;
if (hdr->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)
max_addr = ULONG_MAX;
status = efi_load_initrd_dev_path(&addr, &size, max_addr);
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 boot_params;
fail:
efi_printk("efi_main() failed!\n");
efi_exit(handle, status);
}