Commit 76db5a27 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
Browse files

bootconfig: Add Extra Boot Config support 

Extra Boot Config (XBC) allows admin to pass a tree-structured
boot configuration file when boot up the kernel. This extends
the kernel command line in an efficient way.

Boot config will contain some key-value commands, e.g.

key.word = value1
another.key.word = value2

It can fold same keys with braces, also you can write array
data. For example,

key {
   word1 {
      setting1 = data
      setting2
   }
   word2.array = "val1", "val2"
}

User can access these key-value pair and tree structure via
SKC APIs.

Link: http://lkml.kernel.org/r/157867221257.17873.1775090991929862549.stgit@devnote2



Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 13292494

MAINTAINERS

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@@ -15770,6 +15770,12 @@ W: http://www.stlinux.com 
S:	Supported

F:	drivers/net/ethernet/stmicro/stmmac/













EXTRA BOOT CONFIG













M:	Masami Hiramatsu <mhiramat@kernel.org>













S:	Maintained













F:	lib/bootconfig.c













F:	include/linux/bootconfig.h



























SUN3/3X















M:	Sam Creasey <sammy@sammy.net>















W:	http://sammy.net/sun3/

































include/linux/bootconfig.h
0 → 100644



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/* SPDX-License-Identifier: GPL-2.0 */













#ifndef _LINUX_XBC_H













#define _LINUX_XBC_H













/*













 * Extra Boot Config













 * Copyright (C) 2019 Linaro Ltd.













 * Author: Masami Hiramatsu <mhiramat@kernel.org>













 */



























#include <linux/kernel.h>













#include <linux/types.h>



























/* XBC tree node */













struct xbc_node {













	u16 next;













	u16 child;













	u16 parent;













	u16 data;













} __attribute__ ((__packed__));



























#define XBC_KEY		0













#define XBC_VALUE	(1 << 15)













/* Maximum size of boot config is 32KB - 1 */













#define XBC_DATA_MAX	(XBC_VALUE - 1)



























#define XBC_NODE_MAX	1024













#define XBC_KEYLEN_MAX	256













#define XBC_DEPTH_MAX	16



























/* Node tree access raw APIs */













struct xbc_node * __init xbc_root_node(void);













int __init xbc_node_index(struct xbc_node *node);













struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node);













struct xbc_node * __init xbc_node_get_child(struct xbc_node *node);













struct xbc_node * __init xbc_node_get_next(struct xbc_node *node);













const char * __init xbc_node_get_data(struct xbc_node *node);



























/**













 * xbc_node_is_value() - Test the node is a value node













 * @node: An XBC node.













 *













 * Test the @node is a value node and return true if a value node, false if not.













 */













static inline __init bool xbc_node_is_value(struct xbc_node *node)













{













	return node->data & XBC_VALUE;













}



























/**













 * xbc_node_is_key() - Test the node is a key node













 * @node: An XBC node.













 *













 * Test the @node is a key node and return true if a key node, false if not.













 */













static inline __init bool xbc_node_is_key(struct xbc_node *node)













{













	return !xbc_node_is_value(node);













}



























/**













 * xbc_node_is_array() - Test the node is an arraied value node













 * @node: An XBC node.













 *













 * Test the @node is an arraied value node.













 */













static inline __init bool xbc_node_is_array(struct xbc_node *node)













{













	return xbc_node_is_value(node) && node->next != 0;













}



























/**













 * xbc_node_is_leaf() - Test the node is a leaf key node













 * @node: An XBC node.













 *













 * Test the @node is a leaf key node which is a key node and has a value node













 * or no child. Returns true if it is a leaf node, or false if not.













 */













static inline __init bool xbc_node_is_leaf(struct xbc_node *node)













{













	return xbc_node_is_key(node) &&













		(!node->child || xbc_node_is_value(xbc_node_get_child(node)));













}



























/* Tree-based key-value access APIs */













struct xbc_node * __init xbc_node_find_child(struct xbc_node *parent,













					     const char *key);



























const char * __init xbc_node_find_value(struct xbc_node *parent,













					const char *key,













					struct xbc_node **vnode);



























struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,













						 struct xbc_node *leaf);



























const char * __init xbc_node_find_next_key_value(struct xbc_node *root,













						 struct xbc_node **leaf);



























/**













 * xbc_find_value() - Find a value which matches the key













 * @key: Search key













 * @vnode: A container pointer of XBC value node.













 *













 * Search a value whose key matches @key from whole of XBC tree and return













 * the value if found. Found value node is stored in *@vnode.













 * Note that this can return 0-length string and store NULL in *@vnode for













 * key-only (non-value) entry.













 */













static inline const char * __init













xbc_find_value(const char *key, struct xbc_node **vnode)













{













	return xbc_node_find_value(NULL, key, vnode);













}



























/**













 * xbc_find_node() - Find a node which matches the key













 * @key: Search key













 *













 * Search a (key) node whose key matches @key from whole of XBC tree and













 * return the node if found. If not found, returns NULL.













 */













static inline struct xbc_node * __init xbc_find_node(const char *key)













{













	return xbc_node_find_child(NULL, key);













}



























/**













 * xbc_array_for_each_value() - Iterate value nodes on an array













 * @anode: An XBC arraied value node













 * @value: A value













 *













 * Iterate array value nodes and values starts from @anode. This is expected to













 * be used with xbc_find_value() and xbc_node_find_value(), so that user can













 * process each array entry node.













 */













#define xbc_array_for_each_value(anode, value)				\













	for (value = xbc_node_get_data(anode); anode != NULL ;		\













	     anode = xbc_node_get_next(anode),				\













	     value = anode ? xbc_node_get_data(anode) : NULL)



























/**













 * xbc_node_for_each_child() - Iterate child nodes













 * @parent: An XBC node.













 * @child: Iterated XBC node.













 *













 * Iterate child nodes of @parent. Each child nodes are stored to @child.













 */













#define xbc_node_for_each_child(parent, child)				\













	for (child = xbc_node_get_child(parent); child != NULL ;	\













	     child = xbc_node_get_next(child))



























/**













 * xbc_node_for_each_array_value() - Iterate array entries of geven key













 * @node: An XBC node.













 * @key: A key string searched under @node













 * @anode: Iterated XBC node of array entry.













 * @value: Iterated value of array entry.













 *













 * Iterate array entries of given @key under @node. Each array entry node













 * is stroed to @anode and @value. If the @node doesn't have @key node,













 * it does nothing.













 * Note that even if the found key node has only one value (not array)













 * this executes block once. Hoever, if the found key node has no value













 * (key-only node), this does nothing. So don't use this for testing the













 * key-value pair existence.













 */













#define xbc_node_for_each_array_value(node, key, anode, value)		\













	for (value = xbc_node_find_value(node, key, &anode); value != NULL; \













	     anode = xbc_node_get_next(anode),				\













	     value = anode ? xbc_node_get_data(anode) : NULL)



























/**













 * xbc_node_for_each_key_value() - Iterate key-value pairs under a node













 * @node: An XBC node.













 * @knode: Iterated key node













 * @value: Iterated value string













 *













 * Iterate key-value pairs under @node. Each key node and value string are













 * stored in @knode and @value respectively.













 */













#define xbc_node_for_each_key_value(node, knode, value)			\













	for (knode = NULL, value = xbc_node_find_next_key_value(node, &knode);\













	     knode != NULL; value = xbc_node_find_next_key_value(node, &knode))



























/**













 * xbc_for_each_key_value() - Iterate key-value pairs













 * @knode: Iterated key node













 * @value: Iterated value string













 *













 * Iterate key-value pairs in whole XBC tree. Each key node and value string













 * are stored in @knode and @value respectively.













 */













#define xbc_for_each_key_value(knode, value)				\













	xbc_node_for_each_key_value(NULL, knode, value)



























/* Compose partial key */













int __init xbc_node_compose_key_after(struct xbc_node *root,













			struct xbc_node *node, char *buf, size_t size);



























/**













 * xbc_node_compose_key() - Compose full key string of the XBC node













 * @node: An XBC node.













 * @buf: A buffer to store the key.













 * @size: The size of the @buf.













 *













 * Compose the full-length key of the @node into @buf. Returns the total













 * length of the key stored in @buf. Or returns -EINVAL if @node is NULL,













 * and -ERANGE if the key depth is deeper than max depth.













 */













static inline int __init xbc_node_compose_key(struct xbc_node *node,













					      char *buf, size_t size)













{













	return xbc_node_compose_key_after(NULL, node, buf, size);













}



























/* XBC node initializer */













int __init xbc_init(char *buf);



























/* XBC cleanup data structures */













void __init xbc_destroy_all(void);



























/* Debug dump functions */













void __init xbc_debug_dump(void);



























#endif
























init/Kconfig



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@@ -1215,6 +1215,17 @@ source "usr/Kconfig"





























endif





























config BOOT_CONFIG













	bool "Boot config support"













	select LIBXBC













	default y













	help













	  Extra boot config allows system admin to pass a config file as













	  complemental extension of kernel cmdline when booting.













	  The boot config file is usually attached at the end of initramfs.



























	  If unsure, say Y.





























choice















	prompt "Compiler optimization level"















	default CC_OPTIMIZE_FOR_PERFORMANCE

































lib/Kconfig



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@@ -566,6 +566,9 @@ config DIMLIB













config LIBFDT















	bool





























config LIBXBC













	bool





























config OID_REGISTRY















	tristate















	help

































lib/Makefile



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@@ -228,6 +228,8 @@ $(foreach file, $(libfdt_files), \













	$(eval CFLAGS_$(file) = -I $(srctree)/scripts/dtc/libfdt))















lib-$(CONFIG_LIBFDT) += $(libfdt_files)





























lib-$(CONFIG_LIBXBC) += bootconfig.o





























obj-$(CONFIG_RBTREE_TEST) += rbtree_test.o















obj-$(CONFIG_INTERVAL_TREE_TEST) += interval_tree_test.o

























































































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