1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Common header file for generic dynamic events. 4 */ 5 6 #ifndef _TRACE_DYNEVENT_H 7 #define _TRACE_DYNEVENT_H 8 9 #include <linux/kernel.h> 10 #include <linux/list.h> 11 #include <linux/mutex.h> 12 #include <linux/seq_file.h> 13 14 #include "trace.h" 15 16 struct dyn_event; 17 18 /** 19 * struct dyn_event_operations - Methods for each type of dynamic events 20 * 21 * These methods must be set for each type, since there is no default method. 22 * Before using this for dyn_event_init(), it must be registered by 23 * dyn_event_register(). 24 * 25 * @create: Parse and create event method. This is invoked when user passes 26 * a event definition to dynamic_events interface. This must not destruct 27 * the arguments and return -ECANCELED if given arguments doesn't match its 28 * command prefix. 29 * @show: Showing method. This is invoked when user reads the event definitions 30 * via dynamic_events interface. 31 * @is_busy: Check whether given event is busy so that it can not be deleted. 32 * Return true if it is busy, otherwides false. 33 * @free: Delete the given event. Return 0 if success, otherwides error. 34 * @match: Check whether given event and system name match this event. The argc 35 * and argv is used for exact match. Return true if it matches, otherwides 36 * false. 37 * 38 * Except for @create, these methods are called under holding event_mutex. 39 */ 40 struct dyn_event_operations { 41 struct list_head list; 42 int (*create)(int argc, const char *argv[]); 43 int (*show)(struct seq_file *m, struct dyn_event *ev); 44 bool (*is_busy)(struct dyn_event *ev); 45 int (*free)(struct dyn_event *ev); 46 bool (*match)(const char *system, const char *event, 47 int argc, const char **argv, struct dyn_event *ev); 48 }; 49 50 /* Register new dyn_event type -- must be called at first */ 51 int dyn_event_register(struct dyn_event_operations *ops); 52 53 /** 54 * struct dyn_event - Dynamic event list header 55 * 56 * The dyn_event structure encapsulates a list and a pointer to the operators 57 * for making a global list of dynamic events. 58 * User must includes this in each event structure, so that those events can 59 * be added/removed via dynamic_events interface. 60 */ 61 struct dyn_event { 62 struct list_head list; 63 struct dyn_event_operations *ops; 64 }; 65 66 extern struct list_head dyn_event_list; 67 68 static inline 69 int dyn_event_init(struct dyn_event *ev, struct dyn_event_operations *ops) 70 { 71 if (!ev || !ops) 72 return -EINVAL; 73 74 INIT_LIST_HEAD(&ev->list); 75 ev->ops = ops; 76 return 0; 77 } 78 79 static inline int dyn_event_add(struct dyn_event *ev) 80 { 81 lockdep_assert_held(&event_mutex); 82 83 if (!ev || !ev->ops) 84 return -EINVAL; 85 86 list_add_tail(&ev->list, &dyn_event_list); 87 return 0; 88 } 89 90 static inline void dyn_event_remove(struct dyn_event *ev) 91 { 92 lockdep_assert_held(&event_mutex); 93 list_del_init(&ev->list); 94 } 95 96 void *dyn_event_seq_start(struct seq_file *m, loff_t *pos); 97 void *dyn_event_seq_next(struct seq_file *m, void *v, loff_t *pos); 98 void dyn_event_seq_stop(struct seq_file *m, void *v); 99 int dyn_events_release_all(struct dyn_event_operations *type); 100 int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type); 101 102 /* 103 * for_each_dyn_event - iterate over the dyn_event list 104 * @pos: the struct dyn_event * to use as a loop cursor 105 * 106 * This is just a basement of for_each macro. Wrap this for 107 * each actual event structure with ops filtering. 108 */ 109 #define for_each_dyn_event(pos) \ 110 list_for_each_entry(pos, &dyn_event_list, list) 111 112 /* 113 * for_each_dyn_event - iterate over the dyn_event list safely 114 * @pos: the struct dyn_event * to use as a loop cursor 115 * @n: the struct dyn_event * to use as temporary storage 116 */ 117 #define for_each_dyn_event_safe(pos, n) \ 118 list_for_each_entry_safe(pos, n, &dyn_event_list, list) 119 120 #endif 121