// SPDX-License-Identifier: GPL-2.0/* * Extra Boot Config * Masami Hiramatsu <mhiramat@kernel.org> */ /* * NOTE: This is only for tools/bootconfig, because tools/bootconfig will * run the parser sanity test. * This does NOT mean lib/bootconfig.c is available in the user space. * However, if you change this file, please make sure the tools/bootconfig * has no issue on building and running. */#include <linux/bootconfig.h> #ifdef __KERNEL__#include <linux/bug.h>#include <linux/ctype.h>#include <linux/errno.h>#include <linux/cache.h>#include <linux/compiler.h>#include <linux/init.h>#include <linux/moduleparam.h>#include <linux/printk.h>#include <linux/sprintf.h>#include <linux/memblock.h>#include <linux/string.h>#include <asm/setup.h>		/* COMMAND_LINE_SIZE */ #ifdef CONFIG_BOOT_CONFIG_EMBED/* embedded_bootconfig_data is defined in bootconfig-data.S */extern __visible const char embedded_bootconfig_data[];extern __visible const char embedded_bootconfig_data_end[]; const char * __init xbc_get_embedded_bootconfig(size_t *size){	*size = embedded_bootconfig_data_end - embedded_bootconfig_data;	return (*size) ? embedded_bootconfig_data : NULL;}#endif #ifdef CONFIG_CMDLINE_FROM_BOOTCONFIG/* embedded_kernel_cmdline is defined in embedded-cmdline.S */extern __visible const char embedded_kernel_cmdline[];extern __visible const char embedded_kernel_cmdline_end[]; /* Set once the embedded cmdline has actually been prepended. */static bool xbc_cmdline_applied __initdata; /* * str_prepend() - Prepend @src in front of the string in @dst, in place * @dst: NUL-terminated destination buffer, currently @dst_len bytes long * @dst_len: length of the current @dst string (excluding its NUL) * @src: bytes to prepend (not NUL-terminated) * @src_len: number of bytes from @src to prepend * * The caller must guarantee @dst has room for src_len + dst_len + 1 bytes. * Moving dst_len + 1 bytes carries @dst's NUL terminator too, so an empty * @dst needs no special case. */static void __init str_prepend(char *dst, size_t dst_len,			       const char *src, size_t src_len){	memmove(dst + src_len, dst, dst_len + 1);	memcpy(dst, src, src_len);} /** * xbc_prepend_embedded_cmdline() - Prepend embedded bootconfig cmdline * @dst: cmdline buffer to prepend into (must already contain a NUL byte) * @size: total capacity of @dst in bytes * * Prepend the build-time-rendered "kernel" subtree of the embedded * bootconfig to @dst. The rendered string already ends with a single * space (the xbc_snprint_cmdline() invariant), which serves as the * separator between the embedded keys and any existing content of @dst. * On overflow, log an error and leave @dst untouched rather than * silently truncating: booting without the embedded values is better * than refusing to boot, and the error message tells the user why * their embedded keys are missing. * * Intended to be called from setup_arch() before parse_early_param() so * that early_param() handlers see the embedded values. */void __init xbc_prepend_embedded_cmdline(char *dst, size_t size){	size_t embed_len = embedded_kernel_cmdline_end - embedded_kernel_cmdline;	size_t dst_len; 	if (!size || embed_len <= 1)	/* trailing NUL only */		return;	embed_len--;			/* exclude trailing NUL byte */ 	dst_len = strnlen(dst, size);	if (embed_len + dst_len + 1 > size) {		pr_err("embedded bootconfig cmdline (%zu bytes) does not fit in COMMAND_LINE_SIZE with %zu bytes already used; ignoring embedded values\n",		       embed_len, dst_len);		return;	} 	str_prepend(dst, dst_len, embedded_kernel_cmdline, embed_len);	xbc_cmdline_applied = true;} /** * xbc_embedded_cmdline_applied() - Did the embedded cmdline get prepended? * * Return true if xbc_prepend_embedded_cmdline() actually prepended the * embedded "kernel" subtree. setup_boot_config() uses this to avoid * rendering the same keys a second time. */bool __init xbc_embedded_cmdline_applied(void){	return xbc_cmdline_applied;}#endif	/* CONFIG_CMDLINE_FROM_BOOTCONFIG */ /* parse_args() callback: flag when the "bootconfig" parameter is present. */static int __init bootconfig_optin(char *param, char *val,				   const char *unused, void *arg){	if (!strcmp(param, "bootconfig"))		*(bool *)arg = true;	return 0;} /** * bootconfig_cmdline_requested() - Was "bootconfig" passed on the cmdline? * @boot_cmdline: kernel command line to inspect (not modified) * @end_offset: if non-NULL, set to the offset of the init arguments that *		follow a "--" separator, or 0 when there is none * * Parse a private copy of @boot_cmdline (parse_args() is destructive) and * report whether "bootconfig" is present before the "--" separator. * setup_arch() uses this to gate prepending the build-time embedded cmdline; * setup_boot_config() uses it for the runtime opt-in and to locate the init * arguments via @end_offset. Sharing one parser keeps the early and late * paths agreeing on what counts as opt-in. CONFIG_BOOT_CONFIG_FORCE is not * folded in here; callers apply it where they need it. */bool __init bootconfig_cmdline_requested(const char *boot_cmdline, int *end_offset){	static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;	bool found = false;	char *err; 	if (end_offset)		*end_offset = 0; 	strscpy(tmp_cmdline, boot_cmdline, COMMAND_LINE_SIZE);	err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0,			 &found, bootconfig_optin);	if (IS_ERR(err))		return false; 	/* parse_args() stops at "--" and returns the address of the rest. */	if (end_offset && err)		*end_offset = err - tmp_cmdline; 	return found;} #endif	/* __KERNEL__ */ /* * Extra Boot Config (XBC) is given as tree-structured ascii text of * key-value pairs on memory. * xbc_parse() parses the text to build a simple tree. Each tree node is * simply a key word or a value. A key node may have a next key node or/and * a child node (both key and value). A value node may have a next value * node (for array). */ static struct xbc_node *xbc_nodes __initdata;static int xbc_node_num __initdata;static char *xbc_data __initdata;static size_t xbc_data_size __initdata;static struct xbc_node *last_parent __initdata;static const char *xbc_err_msg __initdata;static int xbc_err_pos __initdata;static int open_brace[XBC_DEPTH_MAX] __initdata;static int brace_index __initdata; #ifdef __KERNEL__static inline void * __init xbc_alloc_mem(size_t size){	return memblock_alloc(size, SMP_CACHE_BYTES);} static inline void __init xbc_free_mem(void *addr, size_t size, bool early){	if (early)		memblock_free(addr, size);	else if (addr)		memblock_free(addr, size);} #else /* !__KERNEL__ */ static inline void *xbc_alloc_mem(size_t size){	return calloc(1, size);} static inline void xbc_free_mem(void *addr, size_t size, bool early){	free(addr);}#endif /** * xbc_get_info() - Get the information of loaded boot config * @node_size: A pointer to store the number of nodes. * @data_size: A pointer to store the size of bootconfig data. * * Get the number of used nodes in @node_size if it is not NULL, * and the size of bootconfig data in @data_size if it is not NULL. * Return 0 if the boot config is initialized, or return -ENODEV. */int __init xbc_get_info(int *node_size, size_t *data_size){	if (!xbc_data)		return -ENODEV; 	if (node_size)		*node_size = xbc_node_num;	if (data_size)		*data_size = xbc_data_size;	return 0;} static int __init xbc_parse_error(const char *msg, const char *p){	xbc_err_msg = msg;	xbc_err_pos = (int)(p - xbc_data); 	return -EINVAL;} /** * xbc_root_node() - Get the root node of extended boot config * * Return the address of root node of extended boot config. If the * extended boot config is not initialized, return NULL. */struct xbc_node * __init xbc_root_node(void){	if (unlikely(!xbc_data))		return NULL; 	return xbc_nodes;} /** * xbc_node_index() - Get the index of XBC node * @node: A target node of getting index. * * Return the index number of @node in XBC node list. */uint16_t __init xbc_node_index(struct xbc_node *node){	return (uint16_t)(node - &xbc_nodes[0]);} /** * xbc_node_get_parent() - Get the parent XBC node * @node: An XBC node. * * Return the parent node of @node. If the node is top node of the tree, * return NULL. */struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node){	return node->parent == XBC_NODE_MAX ? NULL : &xbc_nodes[node->parent];} /** * xbc_node_get_child() - Get the child XBC node * @node: An XBC node. * * Return the first child node of @node. If the node has no child, return * NULL. */struct xbc_node * __init xbc_node_get_child(struct xbc_node *node){	return node->child ? &xbc_nodes[node->child] : NULL;} /** * xbc_node_get_next() - Get the next sibling XBC node * @node: An XBC node. * * Return the NEXT sibling node of @node. If the node has no next sibling, * return NULL. Note that even if this returns NULL, it doesn't mean @node * has no siblings. (You also has to check whether the parent's child node * is @node or not.) */struct xbc_node * __init xbc_node_get_next(struct xbc_node *node){	return node->next ? &xbc_nodes[node->next] : NULL;} /** * xbc_node_get_data() - Get the data of XBC node * @node: An XBC node. * * Return the data (which is always a null terminated string) of @node. * If the node has invalid data, warn and return NULL. */const char * __init xbc_node_get_data(struct xbc_node *node){	size_t offset = node->data & ~XBC_VALUE; 	if (WARN_ON(offset >= xbc_data_size))		return NULL; 	return xbc_data + offset;} static bool __initxbc_node_match_prefix(struct xbc_node *node, const char **prefix){	const char *p = xbc_node_get_data(node);	size_t len = strlen(p); 	if (strncmp(*prefix, p, len))		return false; 	p = *prefix + len;	if (*p == '.')		p++;	else if (*p != '\0')		return false;	*prefix = p; 	return true;} /** * xbc_node_find_subkey() - Find a subkey node which matches given key * @parent: An XBC node. * @key: A key string. * * Search a key node under @parent which matches @key. The @key can contain * several words jointed with '.'. If @parent is NULL, this searches the * node from whole tree. Return NULL if no node is matched. */struct xbc_node * __initxbc_node_find_subkey(struct xbc_node *parent, const char *key){	struct xbc_node *node; 	if (parent)		node = xbc_node_get_subkey(parent);	else		node = xbc_root_node(); 	while (node && xbc_node_is_key(node)) {		if (!xbc_node_match_prefix(node, &key))			node = xbc_node_get_next(node);		else if (*key != '\0')			node = xbc_node_get_subkey(node);		else			break;	} 	return node;} /** * xbc_node_find_value() - Find a value node which matches given key * @parent: An XBC node. * @key: A key string. * @vnode: A container pointer of found XBC node. * * Search a value node under @parent whose (parent) key node matches @key, * store it in *@vnode, and returns the value string. * The @key can contain several words jointed with '.'. If @parent is NULL, * this searches the node from whole tree. Return the value string if a * matched key found, return NULL if no node is matched. * Note that this returns 0-length string and stores NULL in *@vnode if the * key has no value. And also it will return the value of the first entry if * the value is an array. */const char * __initxbc_node_find_value(struct xbc_node *parent, const char *key,		    struct xbc_node **vnode){	struct xbc_node *node = xbc_node_find_subkey(parent, key); 	if (!node || !xbc_node_is_key(node))		return NULL; 	node = xbc_node_get_child(node);	if (node && !xbc_node_is_value(node))		return NULL; 	if (vnode)		*vnode = node; 	return node ? xbc_node_get_data(node) : "";} /** * xbc_node_compose_key_after() - Compose partial key string of the XBC node * @root: Root XBC node * @node: Target XBC node. * @buf: A buffer to store the key. * @size: The size of the @buf. * * Compose the partial key of the @node into @buf, which is starting right * after @root (@root is not included.) If @root is NULL, this returns full * key words of @node. * Returns the total length of the key stored in @buf. Returns -EINVAL * if @node is NULL or @root is not the ancestor of @node or @root is @node, * or returns -ERANGE if the key depth is deeper than max depth. * This is expected to be used with xbc_find_node() to list up all (child) * keys under given key. */int __init xbc_node_compose_key_after(struct xbc_node *root,				      struct xbc_node *node,				      char *buf, size_t size){	uint16_t keys[XBC_DEPTH_MAX];	int depth = 0, ret = 0, total = 0; 	if (!node || node == root)		return -EINVAL; 	if (xbc_node_is_value(node))		node = xbc_node_get_parent(node); 	while (node && node != root) {		keys[depth++] = xbc_node_index(node);		if (depth == XBC_DEPTH_MAX)			return -ERANGE;		node = xbc_node_get_parent(node);	}	if (!node && root)		return -EINVAL; 	while (--depth >= 0) {		node = xbc_nodes + keys[depth];		ret = snprintf(buf, size, "%s%s", xbc_node_get_data(node),			       depth ? "." : "");		if (ret < 0)			return ret;		if (ret >= size) {			size = 0;		} else {			size -= ret;			buf += ret;		}		total += ret;	} 	return total;} /** * xbc_node_find_next_leaf() - Find the next leaf node under given node * @root: An XBC root node * @node: An XBC node which starts from. * * Search the next leaf node (which means the terminal key node) of @node * under @root node (including @root node itself). * Return the next node or NULL if next leaf node is not found. */struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,						 struct xbc_node *node){	struct xbc_node *next; 	if (unlikely(!xbc_data))		return NULL; 	if (!node) {	/* First try */		node = root;		if (!node)			node = xbc_nodes;	} else {		/* Leaf node may have a subkey */		next = xbc_node_get_subkey(node);		if (next) {			node = next;			goto found;		} 		if (node == root)	/* @root was a leaf, no child node. */			return NULL; 		while (!node->next) {			node = xbc_node_get_parent(node);			if (node == root)				return NULL;			/* User passed a node which is not under parent */			if (WARN_ON(!node))				return NULL;		}		node = xbc_node_get_next(node);

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