1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * EFI boot manager
4 *
5 * Copyright (c) 2017 Rob Clark
6 */
7
8 #define LOG_CATEGORY LOGC_EFI
9
10 #include <common.h>
11 #include <charset.h>
12 #include <log.h>
13 #include <malloc.h>
14 #include <efi_default_filename.h>
15 #include <efi_loader.h>
16 #include <efi_variable.h>
17 #include <asm/unaligned.h>
18
19 static const struct efi_boot_services *bs;
20 static const struct efi_runtime_services *rs;
21
22 const efi_guid_t efi_guid_bootmenu_auto_generated =
23 EFICONFIG_AUTO_GENERATED_ENTRY_GUID;
24
25 /*
26 * bootmgr implements the logic of trying to find a payload to boot
27 * based on the BootOrder + BootXXXX variables, and then loading it.
28 *
29 * TODO detecting a special key held (f9?) and displaying a boot menu
30 * like you would get on a PC would be clever.
31 *
32 * TODO if we had a way to write and persist variables after the OS
33 * has started, we'd also want to check OsIndications to see if we
34 * should do normal or recovery boot.
35 */
36
37 /**
38 * expand_media_path() - expand a device path for default file name
39 * @device_path: device path to check against
40 *
41 * If @device_path is a media or disk partition which houses a file
42 * system, this function returns a full device path which contains
43 * an architecture-specific default file name for removable media.
44 *
45 * Return: a newly allocated device path
46 */
47 static
expand_media_path(struct efi_device_path * device_path)48 struct efi_device_path *expand_media_path(struct efi_device_path *device_path)
49 {
50 struct efi_device_path *rem, *full_path;
51 efi_handle_t handle;
52
53 if (!device_path)
54 return NULL;
55
56 /*
57 * If device_path is a (removable) media or partition which provides
58 * simple file system protocol, append a default file name to support
59 * booting from removable media.
60 */
61 handle = efi_dp_find_obj(device_path,
62 &efi_simple_file_system_protocol_guid, &rem);
63 if (handle) {
64 if (rem->type == DEVICE_PATH_TYPE_END) {
65 full_path = efi_dp_from_file(device_path,
66 "/EFI/BOOT/" BOOTEFI_NAME);
67 } else {
68 full_path = efi_dp_dup(device_path);
69 }
70 } else {
71 full_path = efi_dp_dup(device_path);
72 }
73
74 return full_path;
75 }
76
77 /**
78 * try_load_from_file_path() - try to load a file
79 *
80 * Given a file media path iterate through a list of handles and try to
81 * to load the file from each of them until the first success.
82 *
83 * @fs_handles: array of handles with the simple file protocol
84 * @num: number of handles in fs_handles
85 * @fp: file path to open
86 * @handle: on return pointer to handle for loaded image
87 * @removable: if true only consider removable media, else only non-removable
88 */
try_load_from_file_path(efi_handle_t * fs_handles,efi_uintn_t num,struct efi_device_path * fp,efi_handle_t * handle,bool removable)89 static efi_status_t try_load_from_file_path(efi_handle_t *fs_handles,
90 efi_uintn_t num,
91 struct efi_device_path *fp,
92 efi_handle_t *handle,
93 bool removable)
94 {
95 struct efi_handler *handler;
96 struct efi_device_path *dp;
97 int i;
98 efi_status_t ret;
99
100 for (i = 0; i < num; i++) {
101 if (removable != efi_disk_is_removable(fs_handles[i]))
102 continue;
103
104 ret = efi_search_protocol(fs_handles[i], &efi_guid_device_path,
105 &handler);
106 if (ret != EFI_SUCCESS)
107 continue;
108
109 dp = handler->protocol_interface;
110 if (!dp)
111 continue;
112
113 dp = efi_dp_append(dp, fp);
114 if (!dp)
115 continue;
116
117 ret = EFI_CALL(efi_load_image(true, efi_root, dp, NULL, 0,
118 handle));
119 efi_free_pool(dp);
120 if (ret == EFI_SUCCESS)
121 return ret;
122 }
123
124 return EFI_NOT_FOUND;
125 }
126
127 /**
128 * try_load_from_short_path
129 * @fp: file path
130 * @handle: pointer to handle for newly installed image
131 *
132 * Enumerate all the devices which support file system operations,
133 * prepend its media device path to the file path, @fp, and
134 * try to load the file.
135 * This function should be called when handling a short-form path
136 * which is starting with a file device path.
137 *
138 * Return: status code
139 */
try_load_from_short_path(struct efi_device_path * fp,efi_handle_t * handle)140 static efi_status_t try_load_from_short_path(struct efi_device_path *fp,
141 efi_handle_t *handle)
142 {
143 efi_handle_t *fs_handles;
144 efi_uintn_t num;
145 efi_status_t ret;
146
147 ret = EFI_CALL(efi_locate_handle_buffer(
148 BY_PROTOCOL,
149 &efi_simple_file_system_protocol_guid,
150 NULL,
151 &num, &fs_handles));
152 if (ret != EFI_SUCCESS)
153 return ret;
154 if (!num)
155 return EFI_NOT_FOUND;
156
157 /* removable media first */
158 ret = try_load_from_file_path(fs_handles, num, fp, handle, true);
159 if (ret == EFI_SUCCESS)
160 goto out;
161
162 /* fixed media */
163 ret = try_load_from_file_path(fs_handles, num, fp, handle, false);
164 if (ret == EFI_SUCCESS)
165 goto out;
166
167 out:
168 return ret;
169 }
170
171 /**
172 * try_load_entry() - try to load image for boot option
173 *
174 * Attempt to load load-option number 'n', returning device_path and file_path
175 * if successful. This checks that the EFI_LOAD_OPTION is active (enabled)
176 * and that the specified file to boot exists.
177 *
178 * @n: number of the boot option, e.g. 0x0a13 for Boot0A13
179 * @handle: on return handle for the newly installed image
180 * @load_options: load options set on the loaded image protocol
181 * Return: status code
182 */
try_load_entry(u16 n,efi_handle_t * handle,void ** load_options)183 static efi_status_t try_load_entry(u16 n, efi_handle_t *handle,
184 void **load_options)
185 {
186 struct efi_load_option lo;
187 u16 varname[9];
188 void *load_option;
189 efi_uintn_t size;
190 efi_status_t ret;
191
192 efi_create_indexed_name(varname, sizeof(varname), "Boot", n);
193
194 load_option = efi_get_var(varname, &efi_global_variable_guid, &size);
195 if (!load_option)
196 return EFI_LOAD_ERROR;
197
198 ret = efi_deserialize_load_option(&lo, load_option, &size);
199 if (ret != EFI_SUCCESS) {
200 log_warning("Invalid load option for %ls\n", varname);
201 goto error;
202 }
203
204 if (lo.attributes & LOAD_OPTION_ACTIVE) {
205 struct efi_device_path *file_path;
206 u32 attributes;
207
208 log_debug("trying to load \"%ls\" from %pD\n", lo.label,
209 lo.file_path);
210
211 if (EFI_DP_TYPE(lo.file_path, MEDIA_DEVICE, FILE_PATH)) {
212 /* file_path doesn't contain a device path */
213 ret = try_load_from_short_path(lo.file_path, handle);
214 } else {
215 file_path = expand_media_path(lo.file_path);
216 ret = EFI_CALL(efi_load_image(true, efi_root, file_path,
217 NULL, 0, handle));
218 efi_free_pool(file_path);
219 }
220 if (ret != EFI_SUCCESS) {
221 log_warning("Loading %ls '%ls' failed\n",
222 varname, lo.label);
223 goto error;
224 }
225
226 attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
227 EFI_VARIABLE_RUNTIME_ACCESS;
228 ret = efi_set_variable_int(u"BootCurrent",
229 &efi_global_variable_guid,
230 attributes, sizeof(n), &n, false);
231 if (ret != EFI_SUCCESS)
232 goto unload;
233 /* try to register load file2 for initrd's */
234 if (IS_ENABLED(CONFIG_EFI_LOAD_FILE2_INITRD)) {
235 ret = efi_initrd_register();
236 if (ret != EFI_SUCCESS)
237 goto unload;
238 }
239
240 log_info("Booting: %ls\n", lo.label);
241 } else {
242 ret = EFI_LOAD_ERROR;
243 }
244
245 /* Set load options */
246 if (size >= sizeof(efi_guid_t) &&
247 !guidcmp(lo.optional_data, &efi_guid_bootmenu_auto_generated))
248 size = 0;
249
250 if (size) {
251 *load_options = malloc(size);
252 if (!*load_options) {
253 ret = EFI_OUT_OF_RESOURCES;
254 goto error;
255 }
256 memcpy(*load_options, lo.optional_data, size);
257 ret = efi_set_load_options(*handle, size, *load_options);
258 } else {
259 *load_options = NULL;
260 }
261
262 error:
263 free(load_option);
264
265 return ret;
266
267 unload:
268 if (EFI_CALL(efi_unload_image(*handle)) != EFI_SUCCESS)
269 log_err("Unloading image failed\n");
270 free(load_option);
271
272 return ret;
273 }
274
275 /**
276 * efi_bootmgr_load() - try to load from BootNext or BootOrder
277 *
278 * Attempt to load from BootNext or in the order specified by BootOrder
279 * EFI variable, the available load-options, finding and returning
280 * the first one that can be loaded successfully.
281 *
282 * @handle: on return handle for the newly installed image
283 * @load_options: load options set on the loaded image protocol
284 * Return: status code
285 */
efi_bootmgr_load(efi_handle_t * handle,void ** load_options)286 efi_status_t efi_bootmgr_load(efi_handle_t *handle, void **load_options)
287 {
288 u16 bootnext, *bootorder;
289 efi_uintn_t size;
290 int i, num;
291 efi_status_t ret;
292
293 bs = systab.boottime;
294 rs = systab.runtime;
295
296 /* BootNext */
297 size = sizeof(bootnext);
298 ret = efi_get_variable_int(u"BootNext",
299 &efi_global_variable_guid,
300 NULL, &size, &bootnext, NULL);
301 if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
302 /* BootNext does exist here */
303 if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16))
304 log_err("BootNext must be 16-bit integer\n");
305
306 /* delete BootNext */
307 ret = efi_set_variable_int(u"BootNext",
308 &efi_global_variable_guid,
309 0, 0, NULL, false);
310
311 /* load BootNext */
312 if (ret == EFI_SUCCESS) {
313 if (size == sizeof(u16)) {
314 ret = try_load_entry(bootnext, handle,
315 load_options);
316 if (ret == EFI_SUCCESS)
317 return ret;
318 log_warning(
319 "Loading from BootNext failed, falling back to BootOrder\n");
320 }
321 } else {
322 log_err("Deleting BootNext failed\n");
323 }
324 }
325
326 /* BootOrder */
327 bootorder = efi_get_var(u"BootOrder", &efi_global_variable_guid, &size);
328 if (!bootorder) {
329 log_info("BootOrder not defined\n");
330 ret = EFI_NOT_FOUND;
331 goto error;
332 }
333
334 num = size / sizeof(uint16_t);
335 for (i = 0; i < num; i++) {
336 log_debug("trying to load Boot%04X\n", bootorder[i]);
337 ret = try_load_entry(bootorder[i], handle, load_options);
338 if (ret == EFI_SUCCESS)
339 break;
340 }
341
342 free(bootorder);
343
344 error:
345 return ret;
346 }
347