| Ilias Apalodimas | 37c3ca5 | 2021-03-17 21:54:59 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0+ |
| 2 | /* |
| 3 | * Copyright (c) 2020, Linaro Limited |
| 4 | */ |
| 5 | |
| 6 | #define LOG_CATEGORY LOGC_EFI |
| 7 | #include <common.h> |
| 8 | #include <env.h> |
| 9 | #include <malloc.h> |
| 10 | #include <dm.h> |
| 11 | #include <fs.h> |
| 12 | #include <efi_load_initrd.h> |
| 13 | #include <efi_loader.h> |
| 14 | #include <efi_variable.h> |
| 15 | |
| 16 | /** |
| 17 | * efi_create_current_boot_var() - Return Boot#### name were #### is replaced by |
| 18 | * the value of BootCurrent |
| 19 | * |
| 20 | * @var_name: variable name |
| 21 | * @var_name_size: size of var_name |
| 22 | * |
| 23 | * Return: Status code |
| 24 | */ |
| 25 | static efi_status_t efi_create_current_boot_var(u16 var_name[], |
| 26 | size_t var_name_size) |
| 27 | { |
| 28 | efi_uintn_t boot_current_size; |
| 29 | efi_status_t ret; |
| 30 | u16 boot_current; |
| 31 | u16 *pos; |
| 32 | |
| 33 | boot_current_size = sizeof(boot_current); |
| 34 | ret = efi_get_variable_int(L"BootCurrent", |
| 35 | &efi_global_variable_guid, NULL, |
| 36 | &boot_current_size, &boot_current, NULL); |
| 37 | if (ret != EFI_SUCCESS) |
| 38 | goto out; |
| 39 | |
| 40 | pos = efi_create_indexed_name(var_name, var_name_size, "Boot", |
| 41 | boot_current); |
| 42 | if (!pos) { |
| 43 | ret = EFI_OUT_OF_RESOURCES; |
| 44 | goto out; |
| 45 | } |
| 46 | |
| 47 | out: |
| 48 | return ret; |
| 49 | } |
| 50 | |
| 51 | /** |
| 52 | * efi_get_dp_from_boot() - Retrieve and return a device path from an EFI |
| 53 | * Boot### variable. |
| 54 | * A boot option may contain an array of device paths. |
| 55 | * We use a VenMedia() with a specific GUID to identify |
| 56 | * the usage of the array members. This function is |
| 57 | * used to extract a specific device path |
| 58 | * |
| 59 | * @guid: vendor GUID of the VenMedia() device path node identifying the |
| 60 | * device path |
| 61 | * |
| 62 | * Return: device path or NULL. Caller must free the returned value |
| 63 | */ |
| 64 | struct efi_device_path *efi_get_dp_from_boot(const efi_guid_t guid) |
| 65 | { |
| 66 | struct efi_device_path *file_path = NULL; |
| 67 | struct efi_device_path *tmp = NULL; |
| 68 | struct efi_load_option lo; |
| 69 | void *var_value = NULL; |
| 70 | efi_uintn_t size; |
| 71 | efi_status_t ret; |
| 72 | u16 var_name[16]; |
| 73 | |
| 74 | ret = efi_create_current_boot_var(var_name, sizeof(var_name)); |
| 75 | if (ret != EFI_SUCCESS) |
| 76 | return NULL; |
| 77 | |
| 78 | var_value = efi_get_var(var_name, &efi_global_variable_guid, &size); |
| 79 | if (!var_value) |
| 80 | return NULL; |
| 81 | |
| 82 | ret = efi_deserialize_load_option(&lo, var_value, &size); |
| 83 | if (ret != EFI_SUCCESS) |
| 84 | goto out; |
| 85 | |
| 86 | tmp = efi_dp_from_lo(&lo, &size, guid); |
| 87 | if (!tmp) |
| 88 | goto out; |
| 89 | |
| 90 | /* efi_dp_dup will just return NULL if efi_dp_next is NULL */ |
| 91 | file_path = efi_dp_dup(efi_dp_next(tmp)); |
| 92 | |
| 93 | out: |
| 94 | efi_free_pool(tmp); |
| 95 | free(var_value); |
| 96 | |
| 97 | return file_path; |
| 98 | } |