1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * EFI boot manager 4 * 5 * Copyright (c) 2017 Rob Clark 6 */ 7 8 #include <common.h> 9 #include <charset.h> 10 #include <malloc.h> 11 #include <efi_loader.h> 12 #include <asm/unaligned.h> 13 14 static const struct efi_boot_services *bs; 15 static const struct efi_runtime_services *rs; 16 17 /* 18 * bootmgr implements the logic of trying to find a payload to boot 19 * based on the BootOrder + BootXXXX variables, and then loading it. 20 * 21 * TODO detecting a special key held (f9?) and displaying a boot menu 22 * like you would get on a PC would be clever. 23 * 24 * TODO if we had a way to write and persist variables after the OS 25 * has started, we'd also want to check OsIndications to see if we 26 * should do normal or recovery boot. 27 */ 28 29 30 /* Parse serialized data and transform it into efi_load_option structure */ 31 void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data) 32 { 33 lo->attributes = get_unaligned_le32(data); 34 data += sizeof(u32); 35 36 lo->file_path_length = get_unaligned_le16(data); 37 data += sizeof(u16); 38 39 /* FIXME */ 40 lo->label = (u16 *)data; 41 data += (u16_strlen(lo->label) + 1) * sizeof(u16); 42 43 /* FIXME */ 44 lo->file_path = (struct efi_device_path *)data; 45 data += lo->file_path_length; 46 47 lo->optional_data = data; 48 } 49 50 /* 51 * Serialize efi_load_option structure into byte stream for BootXXXX. 52 * Return a size of allocated data. 53 */ 54 unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data) 55 { 56 unsigned long label_len, option_len; 57 unsigned long size; 58 u8 *p; 59 60 label_len = (u16_strlen(lo->label) + 1) * sizeof(u16); 61 option_len = strlen((char *)lo->optional_data); 62 63 /* total size */ 64 size = sizeof(lo->attributes); 65 size += sizeof(lo->file_path_length); 66 size += label_len; 67 size += lo->file_path_length; 68 size += option_len + 1; 69 p = malloc(size); 70 if (!p) 71 return 0; 72 73 /* copy data */ 74 *data = p; 75 memcpy(p, &lo->attributes, sizeof(lo->attributes)); 76 p += sizeof(lo->attributes); 77 78 memcpy(p, &lo->file_path_length, sizeof(lo->file_path_length)); 79 p += sizeof(lo->file_path_length); 80 81 memcpy(p, lo->label, label_len); 82 p += label_len; 83 84 memcpy(p, lo->file_path, lo->file_path_length); 85 p += lo->file_path_length; 86 87 memcpy(p, lo->optional_data, option_len); 88 p += option_len; 89 *(char *)p = '\0'; 90 91 return size; 92 } 93 94 /* free() the result */ 95 static void *get_var(u16 *name, const efi_guid_t *vendor, 96 efi_uintn_t *size) 97 { 98 efi_guid_t *v = (efi_guid_t *)vendor; 99 efi_status_t ret; 100 void *buf = NULL; 101 102 *size = 0; 103 EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf)); 104 if (ret == EFI_BUFFER_TOO_SMALL) { 105 buf = malloc(*size); 106 EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf)); 107 } 108 109 if (ret != EFI_SUCCESS) { 110 free(buf); 111 *size = 0; 112 return NULL; 113 } 114 115 return buf; 116 } 117 118 /* 119 * Attempt to load load-option number 'n', returning device_path and file_path 120 * if successful. This checks that the EFI_LOAD_OPTION is active (enabled) 121 * and that the specified file to boot exists. 122 */ 123 static void *try_load_entry(uint16_t n, struct efi_device_path **device_path, 124 struct efi_device_path **file_path) 125 { 126 struct efi_load_option lo; 127 u16 varname[] = L"Boot0000"; 128 u16 hexmap[] = L"0123456789ABCDEF"; 129 void *load_option, *image = NULL; 130 efi_uintn_t size; 131 132 varname[4] = hexmap[(n & 0xf000) >> 12]; 133 varname[5] = hexmap[(n & 0x0f00) >> 8]; 134 varname[6] = hexmap[(n & 0x00f0) >> 4]; 135 varname[7] = hexmap[(n & 0x000f) >> 0]; 136 137 load_option = get_var(varname, &efi_global_variable_guid, &size); 138 if (!load_option) 139 return NULL; 140 141 efi_deserialize_load_option(&lo, load_option); 142 143 if (lo.attributes & LOAD_OPTION_ACTIVE) { 144 efi_status_t ret; 145 146 debug("%s: trying to load \"%ls\" from %pD\n", 147 __func__, lo.label, lo.file_path); 148 149 ret = efi_load_image_from_path(lo.file_path, &image, &size); 150 151 if (ret != EFI_SUCCESS) 152 goto error; 153 154 printf("Booting: %ls\n", lo.label); 155 efi_dp_split_file_path(lo.file_path, device_path, file_path); 156 } 157 158 error: 159 free(load_option); 160 161 return image; 162 } 163 164 /* 165 * Attempt to load, in the order specified by BootOrder EFI variable, the 166 * available load-options, finding and returning the first one that can 167 * be loaded successfully. 168 */ 169 void *efi_bootmgr_load(struct efi_device_path **device_path, 170 struct efi_device_path **file_path) 171 { 172 uint16_t *bootorder; 173 efi_uintn_t size; 174 void *image = NULL; 175 int i, num; 176 177 bs = systab.boottime; 178 rs = systab.runtime; 179 180 bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size); 181 if (!bootorder) { 182 printf("BootOrder not defined\n"); 183 goto error; 184 } 185 186 num = size / sizeof(uint16_t); 187 for (i = 0; i < num; i++) { 188 debug("%s: trying to load Boot%04X\n", __func__, bootorder[i]); 189 image = try_load_entry(bootorder[i], device_path, file_path); 190 if (image) 191 break; 192 } 193 194 free(bootorder); 195 196 error: 197 return image; 198 } 199