| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * EFI stub implementation that is shared by arm and arm64 architectures. |
| * This should be #included by the EFI stub implementation files. |
| * |
| * Copyright (C) 2013,2014 Linaro Limited |
| * Roy Franz <roy.franz@linaro.org |
| * Copyright (C) 2013 Red Hat, Inc. |
| * Mark Salter <msalter@redhat.com> |
| */ |
| |
| #include <linux/efi.h> |
| #include <linux/libfdt.h> |
| #include <asm/efi.h> |
| |
| #include "efistub.h" |
| |
| /* |
| * This is the base address at which to start allocating virtual memory ranges |
| * for UEFI Runtime Services. |
| * |
| * For ARM/ARM64: |
| * This is in the low TTBR0 range so that we can use |
| * any allocation we choose, and eliminate the risk of a conflict after kexec. |
| * The value chosen is the largest non-zero power of 2 suitable for this purpose |
| * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can |
| * be mapped efficiently. |
| * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split, |
| * map everything below 1 GB. (512 MB is a reasonable upper bound for the |
| * entire footprint of the UEFI runtime services memory regions) |
| * |
| * For RISC-V: |
| * There is no specific reason for which, this address (512MB) can't be used |
| * EFI runtime virtual address for RISC-V. It also helps to use EFI runtime |
| * services on both RV32/RV64. Keep the same runtime virtual address for RISC-V |
| * as well to minimize the code churn. |
| */ |
| #define EFI_RT_VIRTUAL_BASE SZ_512M |
| #define EFI_RT_VIRTUAL_SIZE SZ_512M |
| |
| #ifdef CONFIG_ARM64 |
| # define EFI_RT_VIRTUAL_LIMIT DEFAULT_MAP_WINDOW_64 |
| #else |
| # define EFI_RT_VIRTUAL_LIMIT TASK_SIZE |
| #endif |
| |
| static u64 virtmap_base = EFI_RT_VIRTUAL_BASE; |
| static bool flat_va_mapping; |
| |
| const efi_system_table_t *efi_system_table; |
| |
| static struct screen_info *setup_graphics(void) |
| { |
| efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID; |
| efi_status_t status; |
| unsigned long size; |
| void **gop_handle = NULL; |
| struct screen_info *si = NULL; |
| |
| size = 0; |
| status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, |
| &gop_proto, NULL, &size, gop_handle); |
| if (status == EFI_BUFFER_TOO_SMALL) { |
| si = alloc_screen_info(); |
| if (!si) |
| return NULL; |
| status = efi_setup_gop(si, &gop_proto, size); |
| if (status != EFI_SUCCESS) { |
| free_screen_info(si); |
| return NULL; |
| } |
| } |
| return si; |
| } |
| |
| static void install_memreserve_table(void) |
| { |
| struct linux_efi_memreserve *rsv; |
| efi_guid_t memreserve_table_guid = LINUX_EFI_MEMRESERVE_TABLE_GUID; |
| efi_status_t status; |
| |
| status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(*rsv), |
| (void **)&rsv); |
| if (status != EFI_SUCCESS) { |
| efi_err("Failed to allocate memreserve entry!\n"); |
| return; |
| } |
| |
| rsv->next = 0; |
| rsv->size = 0; |
| atomic_set(&rsv->count, 0); |
| |
| status = efi_bs_call(install_configuration_table, |
| &memreserve_table_guid, rsv); |
| if (status != EFI_SUCCESS) |
| efi_err("Failed to install memreserve config table!\n"); |
| } |
| |
| static u32 get_supported_rt_services(void) |
| { |
| const efi_rt_properties_table_t *rt_prop_table; |
| u32 supported = EFI_RT_SUPPORTED_ALL; |
| |
| rt_prop_table = get_efi_config_table(EFI_RT_PROPERTIES_TABLE_GUID); |
| if (rt_prop_table) |
| supported &= rt_prop_table->runtime_services_supported; |
| |
| return supported; |
| } |
| |
| /* |
| * 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. |
| */ |
| efi_status_t __efiapi efi_pe_entry(efi_handle_t handle, |
| efi_system_table_t *sys_table_arg) |
| { |
| efi_loaded_image_t *image; |
| efi_status_t status; |
| unsigned long image_addr; |
| unsigned long image_size = 0; |
| /* addr/point and size pairs for memory management*/ |
| unsigned long initrd_addr = 0; |
| unsigned long initrd_size = 0; |
| unsigned long fdt_addr = 0; /* Original DTB */ |
| unsigned long fdt_size = 0; |
| char *cmdline_ptr = NULL; |
| int cmdline_size = 0; |
| efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID; |
| unsigned long reserve_addr = 0; |
| unsigned long reserve_size = 0; |
| enum efi_secureboot_mode secure_boot; |
| struct screen_info *si; |
| efi_properties_table_t *prop_tbl; |
| unsigned long max_addr; |
| |
| 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) { |
| status = EFI_INVALID_PARAMETER; |
| goto fail; |
| } |
| |
| status = check_platform_features(); |
| 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 = efi_system_table->boottime->handle_protocol(handle, |
| &loaded_image_proto, (void *)&image); |
| if (status != EFI_SUCCESS) { |
| efi_err("Failed to get loaded image protocol\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(image, &cmdline_size); |
| if (!cmdline_ptr) { |
| efi_err("getting command line via LOADED_IMAGE_PROTOCOL\n"); |
| status = EFI_OUT_OF_RESOURCES; |
| goto fail; |
| } |
| |
| if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || |
| IS_ENABLED(CONFIG_CMDLINE_FORCE) || |
| cmdline_size == 0) { |
| status = efi_parse_options(CONFIG_CMDLINE); |
| if (status != EFI_SUCCESS) { |
| efi_err("Failed to parse options\n"); |
| goto fail_free_cmdline; |
| } |
| } |
| |
| if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0) { |
| status = efi_parse_options(cmdline_ptr); |
| if (status != EFI_SUCCESS) { |
| efi_err("Failed to parse options\n"); |
| goto fail_free_cmdline; |
| } |
| } |
| |
| efi_info("Booting Linux Kernel...\n"); |
| |
| si = setup_graphics(); |
| |
| status = handle_kernel_image(&image_addr, &image_size, |
| &reserve_addr, |
| &reserve_size, |
| image); |
| if (status != EFI_SUCCESS) { |
| efi_err("Failed to relocate kernel\n"); |
| goto fail_free_screeninfo; |
| } |
| |
| efi_retrieve_tpm2_eventlog(); |
| |
| /* Ask the firmware to clear memory on unclean shutdown */ |
| efi_enable_reset_attack_mitigation(); |
| |
| secure_boot = efi_get_secureboot(); |
| |
| /* |
| * Unauthenticated device tree data is a security hazard, so ignore |
| * 'dtb=' unless UEFI Secure Boot is disabled. We assume that secure |
| * boot is enabled if we can't determine its state. |
| */ |
| if (!IS_ENABLED(CONFIG_EFI_ARMSTUB_DTB_LOADER) || |
| secure_boot != efi_secureboot_mode_disabled) { |
| if (strstr(cmdline_ptr, "dtb=")) |
| efi_err("Ignoring DTB from command line.\n"); |
| } else { |
| status = efi_load_dtb(image, &fdt_addr, &fdt_size); |
| |
| if (status != EFI_SUCCESS) { |
| efi_err("Failed to load device tree!\n"); |
| goto fail_free_image; |
| } |
| } |
| |
| if (fdt_addr) { |
| efi_info("Using DTB from command line\n"); |
| } else { |
| /* Look for a device tree configuration table entry. */ |
| fdt_addr = (uintptr_t)get_fdt(&fdt_size); |
| if (fdt_addr) |
| efi_info("Using DTB from configuration table\n"); |
| } |
| |
| if (!fdt_addr) |
| efi_info("Generating empty DTB\n"); |
| |
| if (!efi_noinitrd) { |
| max_addr = efi_get_max_initrd_addr(image_addr); |
| status = efi_load_initrd(image, &initrd_addr, &initrd_size, |
| ULONG_MAX, max_addr); |
| if (status != EFI_SUCCESS) |
| efi_err("Failed to load initrd!\n"); |
| } |
| |
| efi_random_get_seed(); |
| |
| /* |
| * If the NX PE data feature is enabled in the properties table, we |
| * should take care not to create a virtual mapping that changes the |
| * relative placement of runtime services code and data regions, as |
| * they may belong to the same PE/COFF executable image in memory. |
| * The easiest way to achieve that is to simply use a 1:1 mapping. |
| */ |
| prop_tbl = get_efi_config_table(EFI_PROPERTIES_TABLE_GUID); |
| flat_va_mapping = prop_tbl && |
| (prop_tbl->memory_protection_attribute & |
| EFI_PROPERTIES_RUNTIME_MEMORY_PROTECTION_NON_EXECUTABLE_PE_DATA); |
| |
| /* force efi_novamap if SetVirtualAddressMap() is unsupported */ |
| efi_novamap |= !(get_supported_rt_services() & |
| EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP); |
| |
| /* hibernation expects the runtime regions to stay in the same place */ |
| if (!IS_ENABLED(CONFIG_HIBERNATION) && !efi_nokaslr && !flat_va_mapping) { |
| /* |
| * Randomize the base of the UEFI runtime services region. |
| * Preserve the 2 MB alignment of the region by taking a |
| * shift of 21 bit positions into account when scaling |
| * the headroom value using a 32-bit random value. |
| */ |
| static const u64 headroom = EFI_RT_VIRTUAL_LIMIT - |
| EFI_RT_VIRTUAL_BASE - |
| EFI_RT_VIRTUAL_SIZE; |
| u32 rnd; |
| |
| status = efi_get_random_bytes(sizeof(rnd), (u8 *)&rnd); |
| if (status == EFI_SUCCESS) { |
| virtmap_base = EFI_RT_VIRTUAL_BASE + |
| (((headroom >> 21) * rnd) >> (32 - 21)); |
| } |
| } |
| |
| install_memreserve_table(); |
| |
| status = allocate_new_fdt_and_exit_boot(handle, &fdt_addr, |
| initrd_addr, initrd_size, |
| cmdline_ptr, fdt_addr, fdt_size); |
| if (status != EFI_SUCCESS) |
| goto fail_free_initrd; |
| |
| if (IS_ENABLED(CONFIG_ARM)) |
| efi_handle_post_ebs_state(); |
| |
| efi_enter_kernel(image_addr, fdt_addr, fdt_totalsize((void *)fdt_addr)); |
| /* not reached */ |
| |
| fail_free_initrd: |
| efi_err("Failed to update FDT and exit boot services\n"); |
| |
| efi_free(initrd_size, initrd_addr); |
| efi_free(fdt_size, fdt_addr); |
| |
| fail_free_image: |
| efi_free(image_size, image_addr); |
| efi_free(reserve_size, reserve_addr); |
| fail_free_screeninfo: |
| free_screen_info(si); |
| fail_free_cmdline: |
| efi_bs_call(free_pool, cmdline_ptr); |
| fail: |
| return status; |
| } |
| |
| /* |
| * efi_get_virtmap() - create a virtual mapping for the EFI memory map |
| * |
| * This function populates the virt_addr fields of all memory region descriptors |
| * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors |
| * are also copied to @runtime_map, and their total count is returned in @count. |
| */ |
| void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, |
| unsigned long desc_size, efi_memory_desc_t *runtime_map, |
| int *count) |
| { |
| u64 efi_virt_base = virtmap_base; |
| efi_memory_desc_t *in, *out = runtime_map; |
| int l; |
| |
| for (l = 0; l < map_size; l += desc_size) { |
| u64 paddr, size; |
| |
| in = (void *)memory_map + l; |
| if (!(in->attribute & EFI_MEMORY_RUNTIME)) |
| continue; |
| |
| paddr = in->phys_addr; |
| size = in->num_pages * EFI_PAGE_SIZE; |
| |
| in->virt_addr = in->phys_addr; |
| if (efi_novamap) { |
| continue; |
| } |
| |
| /* |
| * Make the mapping compatible with 64k pages: this allows |
| * a 4k page size kernel to kexec a 64k page size kernel and |
| * vice versa. |
| */ |
| if (!flat_va_mapping) { |
| |
| paddr = round_down(in->phys_addr, SZ_64K); |
| size += in->phys_addr - paddr; |
| |
| /* |
| * Avoid wasting memory on PTEs by choosing a virtual |
| * base that is compatible with section mappings if this |
| * region has the appropriate size and physical |
| * alignment. (Sections are 2 MB on 4k granule kernels) |
| */ |
| if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M) |
| efi_virt_base = round_up(efi_virt_base, SZ_2M); |
| else |
| efi_virt_base = round_up(efi_virt_base, SZ_64K); |
| |
| in->virt_addr += efi_virt_base - paddr; |
| efi_virt_base += size; |
| } |
| |
| memcpy(out, in, desc_size); |
| out = (void *)out + desc_size; |
| ++*count; |
| } |
| } |