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