// SPDX-License-Identifier: GPL-2.0-only#include <linux/codetag.h>#include <linux/idr.h>#include <linux/kallsyms.h>#include <linux/module.h>#include <linux/seq_buf.h>#include <linux/slab.h>#include <linux/vmalloc.h> struct codetag_type {	struct list_head link;	unsigned int count;	struct idr mod_idr;	struct rw_semaphore mod_lock; /* protects mod_idr */	struct codetag_type_desc desc;}; struct codetag_range {	struct codetag *start;	struct codetag *stop;}; struct codetag_module {	struct module *mod;	struct codetag_range range;}; static DEFINE_MUTEX(codetag_lock);static LIST_HEAD(codetag_types); void codetag_lock_module_list(struct codetag_type *cttype, bool lock){	if (lock)		down_read(&cttype->mod_lock);	else		up_read(&cttype->mod_lock);} bool codetag_trylock_module_list(struct codetag_type *cttype){	return down_read_trylock(&cttype->mod_lock) != 0;} struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype){	struct codetag_iterator iter = {		.cttype = cttype,		.cmod = NULL,		.mod_id = 0,		.ct = NULL,	}; 	return iter;} static inline struct codetag *get_first_module_ct(struct codetag_module *cmod){	return cmod->range.start < cmod->range.stop ? cmod->range.start : NULL;} static inlinestruct codetag *get_next_module_ct(struct codetag_iterator *iter){	struct codetag *res = (struct codetag *)			((char *)iter->ct + iter->cttype->desc.tag_size); 	return res < iter->cmod->range.stop ? res : NULL;} struct codetag *codetag_next_ct(struct codetag_iterator *iter){	struct codetag_type *cttype = iter->cttype;	struct codetag_module *cmod;	struct codetag *ct; 	lockdep_assert_held(&cttype->mod_lock); 	if (unlikely(idr_is_empty(&cttype->mod_idr)))		return NULL; 	ct = NULL;	while (true) {		cmod = idr_find(&cttype->mod_idr, iter->mod_id); 		/* If module was removed move to the next one */		if (!cmod)			cmod = idr_get_next_ul(&cttype->mod_idr,					       &iter->mod_id); 		/* Exit if no more modules */		if (!cmod)			break; 		if (cmod != iter->cmod) {			iter->cmod = cmod;			ct = get_first_module_ct(cmod);		} else			ct = get_next_module_ct(iter); 		if (ct)			break; 		iter->mod_id++;	} 	iter->ct = ct;	return ct;} void codetag_to_text(struct seq_buf *out, struct codetag *ct){	if (ct->modname)		seq_buf_printf(out, "%s:%u [%s] func:%s",			       ct->filename, ct->lineno,			       ct->modname, ct->function);	else		seq_buf_printf(out, "%s:%u func:%s",			       ct->filename, ct->lineno, ct->function);} static inline size_t range_size(const struct codetag_type *cttype,				const struct codetag_range *range){	return ((char *)range->stop - (char *)range->start) /			cttype->desc.tag_size;} static void *get_symbol(struct module *mod, const char *prefix, const char *name){	DECLARE_SEQ_BUF(sb, KSYM_NAME_LEN);	const char *buf;	void *ret; 	seq_buf_printf(&sb, "%s%s", prefix, name);	if (seq_buf_has_overflowed(&sb))		return NULL; 	buf = seq_buf_str(&sb);	preempt_disable();	ret = mod ?		(void *)find_kallsyms_symbol_value(mod, buf) :		(void *)kallsyms_lookup_name(buf);	preempt_enable(); 	return ret;} static struct codetag_range get_section_range(struct module *mod,					      const char *section){	return (struct codetag_range) {		get_symbol(mod, "__start_", section),		get_symbol(mod, "__stop_", section),	};} static const char *get_mod_name(__maybe_unused struct module *mod){#ifdef CONFIG_MODULES	if (mod)		return mod->name;#endif	return "(built-in)";} static int codetag_module_init(struct codetag_type *cttype, struct module *mod){	struct codetag_range range;	struct codetag_module *cmod;	int err; 	range = get_section_range(mod, cttype->desc.section);	if (!range.start || !range.stop) {		pr_warn("Failed to load code tags of type %s from the module %s\n",			cttype->desc.section, get_mod_name(mod));		return -EINVAL;	} 	/* Ignore empty ranges */	if (range.start == range.stop)		return 0; 	BUG_ON(range.start > range.stop); 	cmod = kmalloc(sizeof(*cmod), GFP_KERNEL);	if (unlikely(!cmod))		return -ENOMEM; 	cmod->mod = mod;	cmod->range = range; 	down_write(&cttype->mod_lock);	err = idr_alloc(&cttype->mod_idr, cmod, 0, 0, GFP_KERNEL);	if (err >= 0) {		cttype->count += range_size(cttype, &range);		if (cttype->desc.module_load)			cttype->desc.module_load(cttype, cmod);	}	up_write(&cttype->mod_lock); 	if (err < 0) {		kfree(cmod);		return err;	} 	return 0;} #ifdef CONFIG_MODULESvoid codetag_load_module(struct module *mod){	struct codetag_type *cttype; 	if (!mod)		return; 	mutex_lock(&codetag_lock);	list_for_each_entry(cttype, &codetag_types, link)		codetag_module_init(cttype, mod);	mutex_unlock(&codetag_lock);} bool codetag_unload_module(struct module *mod){	struct codetag_type *cttype;	bool unload_ok = true; 	if (!mod)		return true; 	mutex_lock(&codetag_lock);	list_for_each_entry(cttype, &codetag_types, link) {		struct codetag_module *found = NULL;		struct codetag_module *cmod;		unsigned long mod_id, tmp; 		down_write(&cttype->mod_lock);		idr_for_each_entry_ul(&cttype->mod_idr, cmod, tmp, mod_id) {			if (cmod->mod && cmod->mod == mod) {				found = cmod;				break;			}		}		if (found) {			if (cttype->desc.module_unload)				if (!cttype->desc.module_unload(cttype, cmod))					unload_ok = false; 			cttype->count -= range_size(cttype, &cmod->range);			idr_remove(&cttype->mod_idr, mod_id);			kfree(cmod);		}		up_write(&cttype->mod_lock);	}	mutex_unlock(&codetag_lock); 	return unload_ok;}#endif /* CONFIG_MODULES */ struct codetag_type *codetag_register_type(const struct codetag_type_desc *desc){	struct codetag_type *cttype;	int err; 	BUG_ON(desc->tag_size <= 0); 	cttype = kzalloc(sizeof(*cttype), GFP_KERNEL);	if (unlikely(!cttype))		return ERR_PTR(-ENOMEM); 	cttype->desc = *desc;	idr_init(&cttype->mod_idr);	init_rwsem(&cttype->mod_lock); 	err = codetag_module_init(cttype, NULL);	if (unlikely(err)) {		kfree(cttype);		return ERR_PTR(err);	} 	mutex_lock(&codetag_lock);	list_add_tail(&cttype->link, &codetag_types);	mutex_unlock(&codetag_lock); 	return cttype;}