1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_XBC_H
3 #define _LINUX_XBC_H
4 /*
5 * Extra Boot Config
6 * Copyright (C) 2019 Linaro Ltd.
7 * Author: Masami Hiramatsu <mhiramat@kernel.org>
8 */
9
10 #ifdef __KERNEL__
11 #include <linux/kernel.h>
12 #include <linux/types.h>
13 bool __init cmdline_has_extra_options(void);
14 #else /* !__KERNEL__ */
15 /*
16 * NOTE: This is only for tools/bootconfig, because tools/bootconfig will
17 * run the parser sanity test.
18 * This does NOT mean linux/bootconfig.h is available in the user space.
19 * However, if you change this file, please make sure the tools/bootconfig
20 * has no issue on building and running.
21 */
22 #endif
23
24 #define BOOTCONFIG_MAGIC "#BOOTCONFIG\n"
25 #define BOOTCONFIG_MAGIC_LEN 12
26 #define BOOTCONFIG_ALIGN_SHIFT 2
27 #define BOOTCONFIG_ALIGN (1 << BOOTCONFIG_ALIGN_SHIFT)
28 #define BOOTCONFIG_ALIGN_MASK (BOOTCONFIG_ALIGN - 1)
29
30 /**
31 * xbc_calc_checksum() - Calculate checksum of bootconfig
32 * @data: Bootconfig data.
33 * @size: The size of the bootconfig data.
34 *
35 * Calculate the checksum value of the bootconfig data.
36 * The checksum will be used with the BOOTCONFIG_MAGIC and the size for
37 * embedding the bootconfig in the initrd image.
38 */
39 static inline __init uint32_t xbc_calc_checksum(void *data, uint32_t size)
40 {
41 unsigned char *p = data;
42 uint32_t ret = 0;
43
44 while (size--)
45 ret += *p++;
46
47 return ret;
48 }
49
50 /* XBC tree node */
51 struct xbc_node {
52 uint16_t next;
53 uint16_t child;
54 uint16_t parent;
55 uint16_t data;
56 } __attribute__ ((__packed__));
57
58 #define XBC_KEY 0
59 #define XBC_VALUE (1 << 15)
60 /* Maximum size of boot config is 32KB - 1 */
61 #define XBC_DATA_MAX (XBC_VALUE - 1)
62
63 #define XBC_NODE_MAX 8192
64 #define XBC_KEYLEN_MAX 256
65 #define XBC_DEPTH_MAX 16
66
67 /* Node tree access raw APIs */
68 struct xbc_node * __init xbc_root_node(void);
69 int __init xbc_node_index(struct xbc_node *node);
70 struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node);
71 struct xbc_node * __init xbc_node_get_child(struct xbc_node *node);
72 struct xbc_node * __init xbc_node_get_next(struct xbc_node *node);
73 const char * __init xbc_node_get_data(struct xbc_node *node);
74
75 /**
76 * xbc_node_is_value() - Test the node is a value node
77 * @node: An XBC node.
78 *
79 * Test the @node is a value node and return true if a value node, false if not.
80 */
81 static inline __init bool xbc_node_is_value(struct xbc_node *node)
82 {
83 return node->data & XBC_VALUE;
84 }
85
86 /**
87 * xbc_node_is_key() - Test the node is a key node
88 * @node: An XBC node.
89 *
90 * Test the @node is a key node and return true if a key node, false if not.
91 */
92 static inline __init bool xbc_node_is_key(struct xbc_node *node)
93 {
94 return !xbc_node_is_value(node);
95 }
96
97 /**
98 * xbc_node_is_array() - Test the node is an arraied value node
99 * @node: An XBC node.
100 *
101 * Test the @node is an arraied value node.
102 */
103 static inline __init bool xbc_node_is_array(struct xbc_node *node)
104 {
105 return xbc_node_is_value(node) && node->child != 0;
106 }
107
108 /**
109 * xbc_node_is_leaf() - Test the node is a leaf key node
110 * @node: An XBC node.
111 *
112 * Test the @node is a leaf key node which is a key node and has a value node
113 * or no child. Returns true if it is a leaf node, or false if not.
114 * Note that the leaf node can have subkey nodes in addition to the
115 * value node.
116 */
117 static inline __init bool xbc_node_is_leaf(struct xbc_node *node)
118 {
119 return xbc_node_is_key(node) &&
120 (!node->child || xbc_node_is_value(xbc_node_get_child(node)));
121 }
122
123 /* Tree-based key-value access APIs */
124 struct xbc_node * __init xbc_node_find_subkey(struct xbc_node *parent,
125 const char *key);
126
127 const char * __init xbc_node_find_value(struct xbc_node *parent,
128 const char *key,
129 struct xbc_node **vnode);
130
131 struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
132 struct xbc_node *leaf);
133
134 const char * __init xbc_node_find_next_key_value(struct xbc_node *root,
135 struct xbc_node **leaf);
136
137 /**
138 * xbc_find_value() - Find a value which matches the key
139 * @key: Search key
140 * @vnode: A container pointer of XBC value node.
141 *
142 * Search a value whose key matches @key from whole of XBC tree and return
143 * the value if found. Found value node is stored in *@vnode.
144 * Note that this can return 0-length string and store NULL in *@vnode for
145 * key-only (non-value) entry.
146 */
147 static inline const char * __init
148 xbc_find_value(const char *key, struct xbc_node **vnode)
149 {
150 return xbc_node_find_value(NULL, key, vnode);
151 }
152
153 /**
154 * xbc_find_node() - Find a node which matches the key
155 * @key: Search key
156 *
157 * Search a (key) node whose key matches @key from whole of XBC tree and
158 * return the node if found. If not found, returns NULL.
159 */
160 static inline struct xbc_node * __init xbc_find_node(const char *key)
161 {
162 return xbc_node_find_subkey(NULL, key);
163 }
164
165 /**
166 * xbc_node_get_subkey() - Return the first subkey node if exists
167 * @node: Parent node
168 *
169 * Return the first subkey node of the @node. If the @node has no child
170 * or only value node, this will return NULL.
171 */
172 static inline struct xbc_node * __init xbc_node_get_subkey(struct xbc_node *node)
173 {
174 struct xbc_node *child = xbc_node_get_child(node);
175
176 if (child && xbc_node_is_value(child))
177 return xbc_node_get_next(child);
178 else
179 return child;
180 }
181
182 /**
183 * xbc_array_for_each_value() - Iterate value nodes on an array
184 * @anode: An XBC arraied value node
185 * @value: A value
186 *
187 * Iterate array value nodes and values starts from @anode. This is expected to
188 * be used with xbc_find_value() and xbc_node_find_value(), so that user can
189 * process each array entry node.
190 */
191 #define xbc_array_for_each_value(anode, value) \
192 for (value = xbc_node_get_data(anode); anode != NULL ; \
193 anode = xbc_node_get_child(anode), \
194 value = anode ? xbc_node_get_data(anode) : NULL)
195
196 /**
197 * xbc_node_for_each_child() - Iterate child nodes
198 * @parent: An XBC node.
199 * @child: Iterated XBC node.
200 *
201 * Iterate child nodes of @parent. Each child nodes are stored to @child.
202 * The @child can be mixture of a value node and subkey nodes.
203 */
204 #define xbc_node_for_each_child(parent, child) \
205 for (child = xbc_node_get_child(parent); child != NULL ; \
206 child = xbc_node_get_next(child))
207
208 /**
209 * xbc_node_for_each_subkey() - Iterate child subkey nodes
210 * @parent: An XBC node.
211 * @child: Iterated XBC node.
212 *
213 * Iterate subkey nodes of @parent. Each child nodes are stored to @child.
214 * The @child is only the subkey node.
215 */
216 #define xbc_node_for_each_subkey(parent, child) \
217 for (child = xbc_node_get_subkey(parent); child != NULL ; \
218 child = xbc_node_get_next(child))
219
220 /**
221 * xbc_node_for_each_array_value() - Iterate array entries of geven key
222 * @node: An XBC node.
223 * @key: A key string searched under @node
224 * @anode: Iterated XBC node of array entry.
225 * @value: Iterated value of array entry.
226 *
227 * Iterate array entries of given @key under @node. Each array entry node
228 * is stored to @anode and @value. If the @node doesn't have @key node,
229 * it does nothing.
230 * Note that even if the found key node has only one value (not array)
231 * this executes block once. However, if the found key node has no value
232 * (key-only node), this does nothing. So don't use this for testing the
233 * key-value pair existence.
234 */
235 #define xbc_node_for_each_array_value(node, key, anode, value) \
236 for (value = xbc_node_find_value(node, key, &anode); value != NULL; \
237 anode = xbc_node_get_child(anode), \
238 value = anode ? xbc_node_get_data(anode) : NULL)
239
240 /**
241 * xbc_node_for_each_key_value() - Iterate key-value pairs under a node
242 * @node: An XBC node.
243 * @knode: Iterated key node
244 * @value: Iterated value string
245 *
246 * Iterate key-value pairs under @node. Each key node and value string are
247 * stored in @knode and @value respectively.
248 */
249 #define xbc_node_for_each_key_value(node, knode, value) \
250 for (knode = NULL, value = xbc_node_find_next_key_value(node, &knode);\
251 knode != NULL; value = xbc_node_find_next_key_value(node, &knode))
252
253 /**
254 * xbc_for_each_key_value() - Iterate key-value pairs
255 * @knode: Iterated key node
256 * @value: Iterated value string
257 *
258 * Iterate key-value pairs in whole XBC tree. Each key node and value string
259 * are stored in @knode and @value respectively.
260 */
261 #define xbc_for_each_key_value(knode, value) \
262 xbc_node_for_each_key_value(NULL, knode, value)
263
264 /* Compose partial key */
265 int __init xbc_node_compose_key_after(struct xbc_node *root,
266 struct xbc_node *node, char *buf, size_t size);
267
268 /**
269 * xbc_node_compose_key() - Compose full key string of the XBC node
270 * @node: An XBC node.
271 * @buf: A buffer to store the key.
272 * @size: The size of the @buf.
273 *
274 * Compose the full-length key of the @node into @buf. Returns the total
275 * length of the key stored in @buf. Or returns -EINVAL if @node is NULL,
276 * and -ERANGE if the key depth is deeper than max depth.
277 */
278 static inline int __init xbc_node_compose_key(struct xbc_node *node,
279 char *buf, size_t size)
280 {
281 return xbc_node_compose_key_after(NULL, node, buf, size);
282 }
283
284 /* XBC node initializer */
285 int __init xbc_init(const char *buf, size_t size, const char **emsg, int *epos);
286
287 /* XBC node and size information */
288 int __init xbc_get_info(int *node_size, size_t *data_size);
289
290 /* XBC cleanup data structures */
291 void __init _xbc_exit(bool early);
292
293 static inline void xbc_exit(void)
294 {
295 _xbc_exit(false);
296 }
297
298 /* XBC embedded bootconfig data in kernel */
299 #ifdef CONFIG_BOOT_CONFIG_EMBED
300 const char * __init xbc_get_embedded_bootconfig(size_t *size);
301 #else
302 static inline const char *xbc_get_embedded_bootconfig(size_t *size)
303 {
304 return NULL;
305 }
306 #endif
307
308 #endif
309
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