1 // SPDX-License-Identifier: GPL-2.0+
5 * Copyright (c) 2017 Rob Clark
10 #include <efi_loader.h>
12 #define READ_ONLY BIT(31)
15 * Mapping between EFI variables and u-boot variables:
17 * efi_$guid_$varname = {attributes}(type)value
21 * efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_OsIndicationsSupported=
22 * "{ro,boot,run}(blob)0000000000000000"
23 * efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_BootOrder=
26 * The attributes are a comma separated list of these possible
30 * + boot - boot-services access
31 * + run - runtime access
33 * NOTE: with current implementation, no variables are available after
34 * ExitBootServices, and all are persisted (if possible).
36 * If not specified, the attributes default to "{boot}".
38 * The required type is one of:
40 * + utf8 - raw utf8 string
41 * + blob - arbitrary length hex string
43 * Maybe a utf16 type would be useful to for a string value to be auto
47 #define MAX_VAR_NAME 31
48 #define MAX_NATIVE_VAR_NAME \
49 (strlen("efi_xxxxxxxx-xxxx-xxxx-xxxxxxxxxxxxxxxx_") + \
50 (MAX_VAR_NAME * MAX_UTF8_PER_UTF16))
52 static int hex(int ch)
54 if (ch >= 'a' && ch <= 'f')
56 if (ch >= '0' && ch <= '9')
58 if (ch >= 'A' && ch <= 'F')
63 static int hex2mem(u8 *mem, const char *hexstr, int size)
68 for (i = 0; i < size; i++) {
72 nibble = hex(*hexstr);
79 nibble = hex(*hexstr);
83 *mem = (*mem << 4) | nibble;
91 static char *mem2hex(char *hexstr, const u8 *mem, int count)
93 static const char hexchars[] = "0123456789abcdef";
97 *hexstr++ = hexchars[ch >> 4];
98 *hexstr++ = hexchars[ch & 0xf];
104 static efi_status_t efi_to_native(char *native, u16 *variable_name,
109 len = utf16_strlen((u16 *)variable_name);
110 if (len >= MAX_VAR_NAME)
111 return EFI_DEVICE_ERROR;
113 native += sprintf(native, "efi_%pUl_", vendor);
114 native = (char *)utf16_to_utf8((u8 *)native, (u16 *)variable_name, len);
120 static const char *prefix(const char *str, const char *prefix)
122 size_t n = strlen(prefix);
123 if (!strncmp(prefix, str, n))
128 /* parse attributes part of variable value, if present: */
129 static const char *parse_attr(const char *str, u32 *attrp)
135 *attrp = EFI_VARIABLE_BOOTSERVICE_ACCESS;
139 while (*str == sep) {
144 if ((s = prefix(str, "ro"))) {
146 } else if ((s = prefix(str, "boot"))) {
147 attr |= EFI_VARIABLE_BOOTSERVICE_ACCESS;
148 } else if ((s = prefix(str, "run"))) {
149 attr |= EFI_VARIABLE_RUNTIME_ACCESS;
151 printf("invalid attribute: %s\n", str);
166 /* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#GetVariable.28.29 */
167 efi_status_t EFIAPI efi_get_variable(u16 *variable_name, efi_guid_t *vendor,
168 u32 *attributes, efi_uintn_t *data_size,
171 char native_name[MAX_NATIVE_VAR_NAME + 1];
173 unsigned long in_size;
177 EFI_ENTRY("\"%ls\" %pUl %p %p %p", variable_name, vendor, attributes,
180 if (!variable_name || !vendor || !data_size)
181 return EFI_EXIT(EFI_INVALID_PARAMETER);
183 ret = efi_to_native(native_name, variable_name, vendor);
185 return EFI_EXIT(ret);
187 debug("%s: get '%s'\n", __func__, native_name);
189 val = env_get(native_name);
191 return EFI_EXIT(EFI_NOT_FOUND);
193 val = parse_attr(val, &attr);
195 in_size = *data_size;
197 if ((s = prefix(val, "(blob)"))) {
198 unsigned len = strlen(s);
200 /* number of hexadecimal digits must be even */
202 return EFI_EXIT(EFI_DEVICE_ERROR);
204 /* two characters per byte: */
209 return EFI_EXIT(EFI_BUFFER_TOO_SMALL);
212 return EFI_EXIT(EFI_INVALID_PARAMETER);
214 if (hex2mem(data, s, len) != len)
215 return EFI_EXIT(EFI_DEVICE_ERROR);
217 debug("%s: got value: \"%s\"\n", __func__, s);
218 } else if ((s = prefix(val, "(utf8)"))) {
219 unsigned len = strlen(s) + 1;
224 return EFI_EXIT(EFI_BUFFER_TOO_SMALL);
227 return EFI_EXIT(EFI_INVALID_PARAMETER);
229 memcpy(data, s, len);
230 ((char *)data)[len] = '\0';
232 debug("%s: got value: \"%s\"\n", __func__, (char *)data);
234 debug("%s: invalid value: '%s'\n", __func__, val);
235 return EFI_EXIT(EFI_DEVICE_ERROR);
239 *attributes = attr & EFI_VARIABLE_MASK;
241 return EFI_EXIT(EFI_SUCCESS);
244 /* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#GetNextVariableName.28.29 */
245 efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
249 EFI_ENTRY("%p \"%ls\" %pUl", variable_name_size, variable_name, vendor);
251 return EFI_EXIT(EFI_DEVICE_ERROR);
254 /* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#SetVariable.28.29 */
255 efi_status_t EFIAPI efi_set_variable(u16 *variable_name, efi_guid_t *vendor,
256 u32 attributes, efi_uintn_t data_size,
259 char native_name[MAX_NATIVE_VAR_NAME + 1];
260 efi_status_t ret = EFI_SUCCESS;
264 EFI_ENTRY("\"%ls\" %pUl %x %zu %p", variable_name, vendor, attributes,
267 if (!variable_name || !vendor)
268 return EFI_EXIT(EFI_INVALID_PARAMETER);
270 ret = efi_to_native(native_name, variable_name, vendor);
272 return EFI_EXIT(ret);
274 #define ACCESS_ATTR (EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS)
276 if ((data_size == 0) || !(attributes & ACCESS_ATTR)) {
277 /* delete the variable: */
278 env_set(native_name, NULL);
279 return EFI_EXIT(EFI_SUCCESS);
282 val = env_get(native_name);
284 parse_attr(val, &attr);
286 if (attr & READ_ONLY)
287 return EFI_EXIT(EFI_WRITE_PROTECTED);
290 val = malloc(2 * data_size + strlen("{ro,run,boot}(blob)") + 1);
292 return EFI_EXIT(EFI_OUT_OF_RESOURCES);
296 /* store attributes: */
297 attributes &= (EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS);
298 s += sprintf(s, "{");
300 u32 attr = 1 << (ffs(attributes) - 1);
302 if (attr == EFI_VARIABLE_BOOTSERVICE_ACCESS)
303 s += sprintf(s, "boot");
304 else if (attr == EFI_VARIABLE_RUNTIME_ACCESS)
305 s += sprintf(s, "run");
309 s += sprintf(s, ",");
311 s += sprintf(s, "}");
314 s += sprintf(s, "(blob)");
315 s = mem2hex(s, data, data_size);
318 debug("%s: setting: %s=%s\n", __func__, native_name, val);
320 if (env_set(native_name, val))
321 ret = EFI_DEVICE_ERROR;
325 return EFI_EXIT(ret);