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mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-09-04 20:19:47 +08:00
linux/drivers/firmware/efi/libstub/x86-stub.c
Linus Torvalds d7dd9b449f EFI updates for v6.6
- one bugfix for x86 mixed mode that did not make it into v6.5
 - first pass of cleanup for the EFI runtime wrappers
 - some cosmetic touchups
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Merge tag 'efi-next-for-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

Pull EFI updates from Ard Biesheuvel:
 "This primarily covers some cleanup work on the EFI runtime wrappers,
  which are shared between all EFI architectures except Itanium, and
  which provide some level of isolation to prevent faults occurring in
  the firmware code (which runs at the same privilege level as the
  kernel) from bringing down the system.

  Beyond that, there is a fix that did not make it into v6.5, and some
  doc fixes and dead code cleanup.

   - one bugfix for x86 mixed mode that did not make it into v6.5

   - first pass of cleanup for the EFI runtime wrappers

   - some cosmetic touchups"

* tag 'efi-next-for-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  x86/efistub: Fix PCI ROM preservation in mixed mode
  efi/runtime-wrappers: Clean up white space and add __init annotation
  acpi/prmt: Use EFI runtime sandbox to invoke PRM handlers
  efi/runtime-wrappers: Don't duplicate setup/teardown code
  efi/runtime-wrappers: Remove duplicated macro for service returning void
  efi/runtime-wrapper: Move workqueue manipulation out of line
  efi/runtime-wrappers: Use type safe encapsulation of call arguments
  efi/riscv: Move EFI runtime call setup/teardown helpers out of line
  efi/arm64: Move EFI runtime call setup/teardown helpers out of line
  efi/riscv: libstub: Fix comment about absolute relocation
  efi: memmap: Remove kernel-doc warnings
  efi: Remove unused extern declaration efi_lookup_mapped_addr()
2023-08-28 16:25:45 -07:00

988 lines
25 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 <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 <asm/kaslr.h>
#include <asm/sev.h>
#include "efistub.h"
#include "x86-stub.h"
const efi_system_table_t *efi_system_table;
const efi_dxe_services_table_t *efi_dxe_table;
static efi_loaded_image_t *image = NULL;
static efi_memory_attribute_protocol_t *memattr;
typedef union sev_memory_acceptance_protocol sev_memory_acceptance_protocol_t;
union sev_memory_acceptance_protocol {
struct {
efi_status_t (__efiapi * allow_unaccepted_memory)(
sev_memory_acceptance_protocol_t *);
};
struct {
u32 allow_unaccepted_memory;
} mixed_mode;
};
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;
}
}
void efi_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;
rounded_start = rounddown(start, EFI_PAGE_SIZE);
rounded_end = roundup(start + size, EFI_PAGE_SIZE);
if (memattr != NULL) {
efi_call_proto(memattr, clear_memory_attributes, rounded_start,
rounded_end - rounded_start, EFI_MEMORY_XP);
return;
}
if (efi_dxe_table == NULL)
return;
/*
* 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);
}
}
}
static void setup_unaccepted_memory(void)
{
efi_guid_t mem_acceptance_proto = OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL_GUID;
sev_memory_acceptance_protocol_t *proto;
efi_status_t status;
if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
return;
/*
* Enable unaccepted memory before calling exit boot services in order
* for the UEFI to not accept all memory on EBS.
*/
status = efi_bs_call(locate_protocol, &mem_acceptance_proto, NULL,
(void **)&proto);
if (status != EFI_SUCCESS)
return;
status = efi_call_proto(proto, allow_unaccepted_memory);
if (status != EFI_SUCCESS)
efi_err("Memory acceptance protocol failed\n");
}
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 __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);
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;
case EFI_UNACCEPTED_MEMORY:
if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY)) {
efi_warn_once(
"The system has unaccepted memory, but kernel does not support it\nConsider enabling CONFIG_UNACCEPTED_MEMORY\n");
continue;
}
e820_type = E820_TYPE_RAM;
process_unaccepted_memory(d->phys_addr,
d->phys_addr + PAGE_SIZE * d->num_pages);
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)
{
struct efi_boot_memmap *map;
efi_status_t status;
__u32 nr_desc;
status = efi_get_memory_map(&map, false);
if (status != EFI_SUCCESS)
return status;
nr_desc = map->map_size / map->desc_size;
if (nr_desc > ARRAY_SIZE(params->e820_table) - EFI_MMAP_NR_SLACK_SLOTS) {
u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table) +
EFI_MMAP_NR_SLACK_SLOTS;
status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
}
if (IS_ENABLED(CONFIG_UNACCEPTED_MEMORY) && status == EFI_SUCCESS)
status = allocate_unaccepted_bitmap(nr_desc, map);
efi_bs_call(free_pool, map);
return status;
}
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;
}
static bool have_unsupported_snp_features(void)
{
u64 unsupported;
unsupported = snp_get_unsupported_features(sev_get_status());
if (unsupported) {
efi_err("Unsupported SEV-SNP features detected: 0x%llx\n",
unsupported);
return true;
}
return false;
}
static void efi_get_seed(void *seed, int size)
{
efi_get_random_bytes(size, seed);
/*
* This only updates seed[0] when running on 32-bit, but in that case,
* seed[1] is not used anyway, as there is no virtual KASLR on 32-bit.
*/
*(unsigned long *)seed ^= kaslr_get_random_long("EFI");
}
static void error(char *str)
{
efi_warn("Decompression failed: %s\n", str);
}
static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry)
{
unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
unsigned long addr, alloc_size, entry;
efi_status_t status;
u32 seed[2] = {};
/* determine the required size of the allocation */
alloc_size = ALIGN(max_t(unsigned long, output_len, kernel_total_size),
MIN_KERNEL_ALIGN);
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
u64 range = KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR - kernel_total_size;
efi_get_seed(seed, sizeof(seed));
virt_addr += (range * seed[1]) >> 32;
virt_addr &= ~(CONFIG_PHYSICAL_ALIGN - 1);
}
status = efi_random_alloc(alloc_size, CONFIG_PHYSICAL_ALIGN, &addr,
seed[0], EFI_LOADER_CODE,
EFI_X86_KERNEL_ALLOC_LIMIT);
if (status != EFI_SUCCESS)
return status;
entry = decompress_kernel((void *)addr, virt_addr, error);
if (entry == ULONG_MAX) {
efi_free(alloc_size, addr);
return EFI_LOAD_ERROR;
}
*kernel_entry = addr + entry;
efi_adjust_memory_range_protection(addr, kernel_total_size);
return EFI_SUCCESS;
}
static void __noreturn enter_kernel(unsigned long kernel_addr,
struct boot_params *boot_params)
{
/* enter decompressed kernel with boot_params pointer in RSI/ESI */
asm("jmp *%0"::"r"(kernel_addr), "S"(boot_params));
unreachable();
}
/*
* On success, this routine will jump to the relocated image directly and never
* return. On failure, it will exit to the firmware via efi_exit() instead of
* returning.
*/
void __noreturn efi_stub_entry(efi_handle_t handle,
efi_system_table_t *sys_table_arg,
struct boot_params *boot_params)
{
efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
struct setup_header *hdr = &boot_params->hdr;
const struct linux_efi_initrd *initrd = NULL;
unsigned long kernel_entry;
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 (have_unsupported_snp_features())
efi_exit(handle, EFI_UNSUPPORTED);
if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES)) {
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;
}
}
/* grab the memory attributes protocol if it exists */
efi_bs_call(locate_protocol, &guid, NULL, (void **)&memattr);
status = efi_setup_5level_paging();
if (status != EFI_SUCCESS) {
efi_err("efi_setup_5level_paging() failed!\n");
goto fail;
}
#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;
}
}
status = efi_decompress_kernel(&kernel_entry);
if (status != EFI_SUCCESS) {
efi_err("Failed to decompress kernel\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);
setup_unaccepted_memory();
status = exit_boot(boot_params, handle);
if (status != EFI_SUCCESS) {
efi_err("exit_boot() failed!\n");
goto fail;
}
/*
* Call the SEV init code while still running with the firmware's
* GDT/IDT, so #VC exceptions will be handled by EFI.
*/
sev_enable(boot_params);
efi_5level_switch();
enter_kernel(kernel_entry, boot_params);
fail:
efi_err("efi_stub_entry() failed!\n");
efi_exit(handle, status);
}
#ifdef CONFIG_EFI_HANDOVER_PROTOCOL
void efi_handover_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
struct boot_params *boot_params)
{
extern char _bss[], _ebss[];
memset(_bss, 0, _ebss - _bss);
efi_stub_entry(handle, sys_table_arg, boot_params);
}
#ifndef CONFIG_EFI_MIXED
extern __alias(efi_handover_entry)
void efi32_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
struct boot_params *boot_params);
extern __alias(efi_handover_entry)
void efi64_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
struct boot_params *boot_params);
#endif
#endif