/*
* Determine whether we're in secure boot mode.
*/
enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg)
{
u32 attr;
u8 secboot, setupmode, moksbstate;
unsigned long size;
efi_status_t status;
size = sizeof(secboot);
status = get_efi_var(efi_SecureBoot_name, &efi_variable_guid,
NULL, &size, &secboot);
if (status != EFI_SUCCESS)
goto out_efi_err;
size = sizeof(setupmode);
status = get_efi_var(efi_SetupMode_name, &efi_variable_guid,
NULL, &size, &setupmode);
if (status != EFI_SUCCESS)
goto out_efi_err;
if (secboot == 0 || setupmode == 1)
return efi_secureboot_mode_disabled;
/*
* See if a user has put the shim into insecure mode. If so, and if the
* variable doesn't have the runtime attribute set, we might as well
* honor that.
*/
size = sizeof(moksbstate);
status = get_efi_var(shim_MokSBState_name, &shim_guid,
&attr, &size, &moksbstate);
/* If it fails, we don't care why. Default to secure */
if (status != EFI_SUCCESS)
goto secure_boot_enabled;
if (!(attr & EFI_VARIABLE_RUNTIME_ACCESS) && moksbstate == 1)
return efi_secureboot_mode_disabled;
secure_boot_enabled:
pr_efi(sys_table_arg, "UEFI Secure Boot is enabled.\n");
return efi_secureboot_mode_enabled;
out_efi_err:
pr_efi_err(sys_table_arg, "Could not determine UEFI Secure Boot status.\n");
if (status == EFI_NOT_FOUND)
return efi_secureboot_mode_disabled;
return efi_secureboot_mode_unknown;
}
/*
* EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
* that is described in the PE/COFF header. Most of the code is the same
* for both archictectures, with the arch-specific code provided in the
* handle_kernel_image() function.
*/
unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
unsigned long *image_addr)
{
efi_loaded_image_t *image;
efi_status_t status;
unsigned long image_size = 0;
unsigned long dram_base;
/* addr/point and size pairs for memory management*/
unsigned long initrd_addr;
u64 initrd_size = 0;
unsigned long fdt_addr = 0; /* Original DTB */
unsigned long fdt_size = 0;
char *cmdline_ptr = NULL;
int cmdline_size = 0;
unsigned long new_fdt_addr;
efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
unsigned long reserve_addr = 0;
unsigned long reserve_size = 0;
int secure_boot = 0;
struct screen_info *si;
/* Check if we were booted by the EFI firmware */
if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
goto fail;
pr_efi(sys_table, "Booting Linux Kernel...\n");
status = check_platform_features(sys_table);
if (status != EFI_SUCCESS)
goto fail;
/*
* Get a handle to the loaded image protocol. This is used to get
* information about the running image, such as size and the command
* line.
*/
status = sys_table->boottime->handle_protocol(handle,
&loaded_image_proto, (void *)&image);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
goto fail;
}
dram_base = get_dram_base(sys_table);
if (dram_base == EFI_ERROR) {
pr_efi_err(sys_table, "Failed to find DRAM base\n");
goto fail;
}
/*
* Get the command line from EFI, using the LOADED_IMAGE
* protocol. We are going to copy the command line into the
* device tree, so this can be allocated anywhere.
*/
cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
if (!cmdline_ptr) {
pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
goto fail;
}
/* check whether 'nokaslr' was passed on the command line */
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
static const u8 default_cmdline[] = CONFIG_CMDLINE;
const u8 *str, *cmdline = cmdline_ptr;
if (IS_ENABLED(CONFIG_CMDLINE_FORCE))
cmdline = default_cmdline;
str = strstr(cmdline, "nokaslr");
if (str == cmdline || (str > cmdline && *(str - 1) == ' '))
__nokaslr = true;
}
si = setup_graphics(sys_table);
status = handle_kernel_image(sys_table, image_addr, &image_size,
&reserve_addr,
&reserve_size,
dram_base, image);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table, "Failed to relocate kernel\n");
goto fail_free_cmdline;
}
status = efi_parse_options(cmdline_ptr);
if (status != EFI_SUCCESS)
pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n");
secure_boot = efi_get_secureboot(sys_table);
if (secure_boot > 0)
pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
if (secure_boot < 0) {
pr_efi_err(sys_table,
"could not determine UEFI Secure Boot status.\n");
}
/*
* Unauthenticated device tree data is a security hazard, so
* ignore 'dtb=' unless UEFI Secure Boot is disabled.
*/
if (secure_boot != 0 && strstr(cmdline_ptr, "dtb=")) {
pr_efi(sys_table, "Ignoring DTB from command line.\n");
} else {
status = handle_cmdline_files(sys_table, image, cmdline_ptr,
"dtb=",
~0UL, &fdt_addr, &fdt_size);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table, "Failed to load device tree!\n");
goto fail_free_image;
}
}
if (fdt_addr) {
pr_efi(sys_table, "Using DTB from command line\n");
} else {
/* Look for a device tree configuration table entry. */
fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
if (fdt_addr)
pr_efi(sys_table, "Using DTB from configuration table\n");
}
if (!fdt_addr)
pr_efi(sys_table, "Generating empty DTB\n");
status = handle_cmdline_files(sys_table, image, cmdline_ptr,
"initrd=", dram_base + SZ_512M,
(unsigned long *)&initrd_addr,
(unsigned long *)&initrd_size);
if (status != EFI_SUCCESS)
pr_efi_err(sys_table, "Failed initrd from command line!\n");
efi_random_get_seed(sys_table);
new_fdt_addr = fdt_addr;
status = allocate_new_fdt_and_exit_boot(sys_table, handle,
&new_fdt_addr, dram_base + MAX_FDT_OFFSET,
initrd_addr, initrd_size, cmdline_ptr,
fdt_addr, fdt_size);
/*
* If all went well, we need to return the FDT address to the
* calling function so it can be passed to kernel as part of
* the kernel boot protocol.
*/
if (status == EFI_SUCCESS)
return new_fdt_addr;
pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
efi_free(sys_table, initrd_size, initrd_addr);
efi_free(sys_table, fdt_size, fdt_addr);
fail_free_image:
efi_free(sys_table, image_size, *image_addr);
efi_free(sys_table, reserve_size, reserve_addr);
fail_free_cmdline:
free_screen_info(sys_table, si);
efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
fail:
return EFI_ERROR;
}
efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
void *handle,
unsigned long *new_fdt_addr,
unsigned long max_addr,
u64 initrd_addr, u64 initrd_size,
char *cmdline_ptr,
unsigned long fdt_addr,
unsigned long fdt_size)
{
unsigned long map_size, desc_size, buff_size;
u32 desc_ver;
unsigned long mmap_key;
efi_memory_desc_t *memory_map, *runtime_map;
unsigned long new_fdt_size;
efi_status_t status;
int runtime_entry_count = 0;
struct efi_boot_memmap map;
struct exit_boot_struct priv;
map.map = &runtime_map;
map.map_size = &map_size;
map.desc_size = &desc_size;
map.desc_ver = &desc_ver;
map.key_ptr = &mmap_key;
map.buff_size = &buff_size;
/*
* Get a copy of the current memory map that we will use to prepare
* the input for SetVirtualAddressMap(). We don't have to worry about
* subsequent allocations adding entries, since they could not affect
* the number of EFI_MEMORY_RUNTIME regions.
*/
status = efi_get_memory_map(sys_table, &map);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n");
return status;
}
pr_efi(sys_table,
"Exiting boot services and installing virtual address map...\n");
map.map = &memory_map;
/*
* Estimate size of new FDT, and allocate memory for it. We
* will allocate a bigger buffer if this ends up being too
* small, so a rough guess is OK here.
*/
new_fdt_size = fdt_size + EFI_PAGE_SIZE;
while (1) {
status = efi_high_alloc(sys_table, new_fdt_size, EFI_FDT_ALIGN,
new_fdt_addr, max_addr);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n");
goto fail;
}
/*
* Now that we have done our final memory allocation (and free)
* we can get the memory map key needed for
* exit_boot_services().
*/
status = efi_get_memory_map(sys_table, &map);
if (status != EFI_SUCCESS)
goto fail_free_new_fdt;
status = update_fdt(sys_table,
(void *)fdt_addr, fdt_size,
(void *)*new_fdt_addr, new_fdt_size,
cmdline_ptr, initrd_addr, initrd_size,
memory_map, map_size, desc_size, desc_ver);
/* Succeeding the first time is the expected case. */
if (status == EFI_SUCCESS)
break;
if (status == EFI_BUFFER_TOO_SMALL) {
/*
* We need to allocate more space for the new
* device tree, so free existing buffer that is
* too small. Also free memory map, as we will need
* to get new one that reflects the free/alloc we do
* on the device tree buffer.
*/
efi_free(sys_table, new_fdt_size, *new_fdt_addr);
sys_table->boottime->free_pool(memory_map);
new_fdt_size += EFI_PAGE_SIZE;
} else {
pr_efi_err(sys_table, "Unable to construct new device tree.\n");
goto fail_free_mmap;
}
}
sys_table->boottime->free_pool(memory_map);
priv.runtime_map = runtime_map;
priv.runtime_entry_count = &runtime_entry_count;
status = efi_exit_boot_services(sys_table, handle, &map, &priv,
exit_boot_func);
if (status == EFI_SUCCESS) {
efi_set_virtual_address_map_t *svam;
/* Install the new virtual address map */
svam = sys_table->runtime->set_virtual_address_map;
status = svam(runtime_entry_count * desc_size, desc_size,
desc_ver, runtime_map);
/*
* We are beyond the point of no return here, so if the call to
* SetVirtualAddressMap() failed, we need to signal that to the
* incoming kernel but proceed normally otherwise.
*/
if (status != EFI_SUCCESS) {
int l;
/*
* Set the virtual address field of all
* EFI_MEMORY_RUNTIME entries to 0. This will signal
* the incoming kernel that no virtual translation has
* been installed.
*/
for (l = 0; l < map_size; l += desc_size) {
efi_memory_desc_t *p = (void *)memory_map + l;
if (p->attribute & EFI_MEMORY_RUNTIME)
p->virt_addr = 0;
}
}
return EFI_SUCCESS;
}
pr_efi_err(sys_table, "Exit boot services failed.\n");
fail_free_mmap:
sys_table->boottime->free_pool(memory_map);
fail_free_new_fdt:
efi_free(sys_table, new_fdt_size, *new_fdt_addr);
fail:
sys_table->boottime->free_pool(runtime_map);
return EFI_LOAD_ERROR;
}
