1 // SPDX-License-Identifier: GPL-2.0+
5 * Copyright (c) 2017 Rob Clark
11 #include <efi_loader.h>
12 #include <asm/unaligned.h>
14 static const struct efi_boot_services *bs;
15 static const struct efi_runtime_services *rs;
18 * bootmgr implements the logic of trying to find a payload to boot
19 * based on the BootOrder + BootXXXX variables, and then loading it.
21 * TODO detecting a special key held (f9?) and displaying a boot menu
22 * like you would get on a PC would be clever.
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.
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)
33 lo->attributes = get_unaligned_le32(data);
36 lo->file_path_length = get_unaligned_le16(data);
40 lo->label = (u16 *)data;
41 data += (u16_strlen(lo->label) + 1) * sizeof(u16);
44 lo->file_path = (struct efi_device_path *)data;
45 data += lo->file_path_length;
47 lo->optional_data = data;
51 * Serialize efi_load_option structure into byte stream for BootXXXX.
52 * Return a size of allocated data.
54 unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data)
56 unsigned long label_len, option_len;
60 label_len = (u16_strlen(lo->label) + 1) * sizeof(u16);
61 option_len = strlen((char *)lo->optional_data);
64 size = sizeof(lo->attributes);
65 size += sizeof(lo->file_path_length);
67 size += lo->file_path_length;
68 size += option_len + 1;
75 memcpy(p, &lo->attributes, sizeof(lo->attributes));
76 p += sizeof(lo->attributes);
78 memcpy(p, &lo->file_path_length, sizeof(lo->file_path_length));
79 p += sizeof(lo->file_path_length);
81 memcpy(p, lo->label, label_len);
84 memcpy(p, lo->file_path, lo->file_path_length);
85 p += lo->file_path_length;
87 memcpy(p, lo->optional_data, option_len);
94 /* free() the result */
95 static void *get_var(u16 *name, const efi_guid_t *vendor,
98 efi_guid_t *v = (efi_guid_t *)vendor;
103 EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf));
104 if (ret == EFI_BUFFER_TOO_SMALL) {
106 EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf));
109 if (ret != EFI_SUCCESS) {
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.
123 static void *try_load_entry(uint16_t n, struct efi_device_path **device_path,
124 struct efi_device_path **file_path)
126 struct efi_load_option lo;
127 u16 varname[] = L"Boot0000";
128 u16 hexmap[] = L"0123456789ABCDEF";
129 void *load_option, *image = NULL;
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];
137 load_option = get_var(varname, &efi_global_variable_guid, &size);
141 efi_deserialize_load_option(&lo, load_option);
143 if (lo.attributes & LOAD_OPTION_ACTIVE) {
147 debug("%s: trying to load \"%ls\" from %pD\n",
148 __func__, lo.label, lo.file_path);
150 ret = efi_load_image_from_path(lo.file_path, &image, &size);
152 if (ret != EFI_SUCCESS)
155 attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
156 EFI_VARIABLE_RUNTIME_ACCESS;
158 ret = EFI_CALL(efi_set_variable(
160 (efi_guid_t *)&efi_global_variable_guid,
161 attributes, size, &n));
162 if (ret != EFI_SUCCESS)
165 printf("Booting: %ls\n", lo.label);
166 efi_dp_split_file_path(lo.file_path, device_path, file_path);
176 * Attempt to load from BootNext or in the order specified by BootOrder
177 * EFI variable, the available load-options, finding and returning
178 * the first one that can be loaded successfully.
180 void *efi_bootmgr_load(struct efi_device_path **device_path,
181 struct efi_device_path **file_path)
183 u16 bootnext, *bootorder;
189 bs = systab.boottime;
194 size = sizeof(bootnext);
195 ret = EFI_CALL(efi_get_variable(L"BootNext",
196 (efi_guid_t *)&efi_global_variable_guid,
197 NULL, &size, &bootnext));
198 if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
199 /* BootNext does exist here */
200 if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16))
201 printf("BootNext must be 16-bit integer\n");
203 /* delete BootNext */
204 ret = EFI_CALL(efi_set_variable(
206 (efi_guid_t *)&efi_global_variable_guid,
210 if (ret == EFI_SUCCESS) {
211 if (size == sizeof(u16)) {
212 image = try_load_entry(bootnext, device_path,
218 printf("Deleting BootNext failed\n");
223 bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
225 printf("BootOrder not defined\n");
229 num = size / sizeof(uint16_t);
230 for (i = 0; i < num; i++) {
231 debug("%s: trying to load Boot%04X\n", __func__, bootorder[i]);
232 image = try_load_entry(bootorder[i], device_path, file_path);