1 // SPDX-License-Identifier: GPL-2.0+
5 * Copyright (c) 2017 Rob Clark
8 #define LOG_CATEGORY LOGC_EFI
14 #include <efi_loader.h>
15 #include <efi_variable.h>
16 #include <asm/unaligned.h>
18 static const struct efi_boot_services *bs;
19 static const struct efi_runtime_services *rs;
22 * bootmgr implements the logic of trying to find a payload to boot
23 * based on the BootOrder + BootXXXX variables, and then loading it.
25 * TODO detecting a special key held (f9?) and displaying a boot menu
26 * like you would get on a PC would be clever.
28 * TODO if we had a way to write and persist variables after the OS
29 * has started, we'd also want to check OsIndications to see if we
30 * should do normal or recovery boot.
34 * get_var() - get UEFI variable
36 * It is the caller's duty to free the returned buffer.
38 * @name: name of variable
39 * @vendor: vendor GUID of variable
40 * @size: size of allocated buffer
41 * Return: buffer with variable data or NULL
43 static void *get_var(u16 *name, const efi_guid_t *vendor,
50 ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL);
51 if (ret == EFI_BUFFER_TOO_SMALL) {
53 ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL);
56 if (ret != EFI_SUCCESS) {
66 * try_load_entry() - try to load image for boot option
68 * Attempt to load load-option number 'n', returning device_path and file_path
69 * if successful. This checks that the EFI_LOAD_OPTION is active (enabled)
70 * and that the specified file to boot exists.
72 * @n: number of the boot option, e.g. 0x0a13 for Boot0A13
73 * @handle: on return handle for the newly installed image
74 * @load_options: load options set on the loaded image protocol
77 static efi_status_t try_load_entry(u16 n, efi_handle_t *handle,
80 struct efi_load_option lo;
81 u16 varname[] = L"Boot0000";
82 u16 hexmap[] = L"0123456789ABCDEF";
87 varname[4] = hexmap[(n & 0xf000) >> 12];
88 varname[5] = hexmap[(n & 0x0f00) >> 8];
89 varname[6] = hexmap[(n & 0x00f0) >> 4];
90 varname[7] = hexmap[(n & 0x000f) >> 0];
92 load_option = get_var(varname, &efi_global_variable_guid, &size);
94 return EFI_LOAD_ERROR;
96 ret = efi_deserialize_load_option(&lo, load_option, &size);
97 if (ret != EFI_SUCCESS) {
98 log_warning("Invalid load option for %ls\n", varname);
102 if (lo.attributes & LOAD_OPTION_ACTIVE) {
105 log_debug("%s: trying to load \"%ls\" from %pD\n",
106 __func__, lo.label, lo.file_path);
108 ret = EFI_CALL(efi_load_image(true, efi_root, lo.file_path,
110 if (ret != EFI_SUCCESS) {
111 log_warning("Loading %ls '%ls' failed\n",
116 attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
117 EFI_VARIABLE_RUNTIME_ACCESS;
118 ret = efi_set_variable_int(L"BootCurrent",
119 &efi_global_variable_guid,
120 attributes, sizeof(n), &n, false);
121 if (ret != EFI_SUCCESS)
123 /* try to register load file2 for initrd's */
124 if (IS_ENABLED(CONFIG_EFI_LOAD_FILE2_INITRD)) {
125 ret = efi_initrd_register();
126 if (ret != EFI_SUCCESS)
130 log_info("Booting: %ls\n", lo.label);
132 ret = EFI_LOAD_ERROR;
135 /* Set load options */
137 *load_options = malloc(size);
138 if (!*load_options) {
139 ret = EFI_OUT_OF_RESOURCES;
142 memcpy(*load_options, lo.optional_data, size);
143 ret = efi_set_load_options(*handle, size, *load_options);
145 *load_options = NULL;
154 if (EFI_CALL(efi_unload_image(*handle)) != EFI_SUCCESS)
155 log_err("Unloading image failed\n");
162 * efi_bootmgr_load() - try to load from BootNext or BootOrder
164 * Attempt to load from BootNext or in the order specified by BootOrder
165 * EFI variable, the available load-options, finding and returning
166 * the first one that can be loaded successfully.
168 * @handle: on return handle for the newly installed image
169 * @load_options: load options set on the loaded image protocol
170 * Return: status code
172 efi_status_t efi_bootmgr_load(efi_handle_t *handle, void **load_options)
174 u16 bootnext, *bootorder;
179 bs = systab.boottime;
183 size = sizeof(bootnext);
184 ret = efi_get_variable_int(L"BootNext",
185 &efi_global_variable_guid,
186 NULL, &size, &bootnext, NULL);
187 if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
188 /* BootNext does exist here */
189 if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16))
190 log_err("BootNext must be 16-bit integer\n");
192 /* delete BootNext */
193 ret = efi_set_variable_int(L"BootNext",
194 &efi_global_variable_guid,
198 if (ret == EFI_SUCCESS) {
199 if (size == sizeof(u16)) {
200 ret = try_load_entry(bootnext, handle,
202 if (ret == EFI_SUCCESS)
205 "Loading from BootNext failed, falling back to BootOrder\n");
208 log_err("Deleting BootNext failed\n");
213 bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
215 log_info("BootOrder not defined\n");
220 num = size / sizeof(uint16_t);
221 for (i = 0; i < num; i++) {
222 log_debug("%s trying to load Boot%04X\n", __func__,
224 ret = try_load_entry(bootorder[i], handle, load_options);
225 if (ret == EFI_SUCCESS)