1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* Simple ftrace probe wrapper */ 3 #ifndef _LINUX_FPROBE_H 4 #define _LINUX_FPROBE_H 5 6 #include <linux/compiler.h> 7 #include <linux/ftrace.h> 8 #include <linux/rcupdate.h> 9 #include <linux/refcount.h> 10 #include <linux/slab.h> 11 12 struct fprobe; 13 typedef int (*fprobe_entry_cb)(struct fprobe *fp, unsigned long entry_ip, 14 unsigned long ret_ip, struct ftrace_regs *regs, 15 void *entry_data); 16 17 typedef void (*fprobe_exit_cb)(struct fprobe *fp, unsigned long entry_ip, 18 unsigned long ret_ip, struct ftrace_regs *regs, 19 void *entry_data); 20 21 /** 22 * struct fprobe_hlist_node - address based hash list node for fprobe. 23 * 24 * @hlist: The hlist node for address search hash table. 25 * @addr: One of the probing address of @fp. 26 * @fp: The fprobe which owns this. 27 */ 28 struct fprobe_hlist_node { 29 struct hlist_node hlist; 30 unsigned long addr; 31 struct fprobe *fp; 32 }; 33 34 /** 35 * struct fprobe_hlist - hash list nodes for fprobe. 36 * 37 * @hlist: The hlist node for existence checking hash table. 38 * @rcu: rcu_head for RCU deferred release. 39 * @fp: The fprobe which owns this fprobe_hlist. 40 * @size: The size of @array. 41 * @array: The fprobe_hlist_node for each address to probe. 42 */ 43 struct fprobe_hlist { 44 struct hlist_node hlist; 45 struct rcu_head rcu; 46 struct fprobe *fp; 47 int size; 48 struct fprobe_hlist_node array[] __counted_by(size); 49 }; 50 51 /** 52 * struct fprobe - ftrace based probe. 53 * 54 * @nmissed: The counter for missing events. 55 * @flags: The status flag. 56 * @entry_data_size: The private data storage size. 57 * @entry_handler: The callback function for function entry. 58 * @exit_handler: The callback function for function exit. 59 * @hlist_array: The fprobe_hlist for fprobe search from IP hash table. 60 */ 61 struct fprobe { 62 unsigned long nmissed; 63 unsigned int flags; 64 size_t entry_data_size; 65 66 fprobe_entry_cb entry_handler; 67 fprobe_exit_cb exit_handler; 68 69 struct fprobe_hlist *hlist_array; 70 }; 71 72 /* This fprobe is soft-disabled. */ 73 #define FPROBE_FL_DISABLED 1 74 75 /* 76 * This fprobe handler will be shared with kprobes. 77 * This flag must be set before registering. 78 */ 79 #define FPROBE_FL_KPROBE_SHARED 2 80 81 static inline bool fprobe_disabled(struct fprobe *fp) 82 { 83 return (fp) ? fp->flags & FPROBE_FL_DISABLED : false; 84 } 85 86 static inline bool fprobe_shared_with_kprobes(struct fprobe *fp) 87 { 88 return (fp) ? fp->flags & FPROBE_FL_KPROBE_SHARED : false; 89 } 90 91 #ifdef CONFIG_FPROBE 92 int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter); 93 int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num); 94 int register_fprobe_syms(struct fprobe *fp, const char **syms, int num); 95 int unregister_fprobe(struct fprobe *fp); 96 bool fprobe_is_registered(struct fprobe *fp); 97 #else 98 static inline int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter) 99 { 100 return -EOPNOTSUPP; 101 } 102 static inline int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num) 103 { 104 return -EOPNOTSUPP; 105 } 106 static inline int register_fprobe_syms(struct fprobe *fp, const char **syms, int num) 107 { 108 return -EOPNOTSUPP; 109 } 110 static inline int unregister_fprobe(struct fprobe *fp) 111 { 112 return -EOPNOTSUPP; 113 } 114 static inline bool fprobe_is_registered(struct fprobe *fp) 115 { 116 return false; 117 } 118 #endif 119 120 /** 121 * disable_fprobe() - Disable fprobe 122 * @fp: The fprobe to be disabled. 123 * 124 * This will soft-disable @fp. Note that this doesn't remove the ftrace 125 * hooks from the function entry. 126 */ 127 static inline void disable_fprobe(struct fprobe *fp) 128 { 129 if (fp) 130 fp->flags |= FPROBE_FL_DISABLED; 131 } 132 133 /** 134 * enable_fprobe() - Enable fprobe 135 * @fp: The fprobe to be enabled. 136 * 137 * This will soft-enable @fp. 138 */ 139 static inline void enable_fprobe(struct fprobe *fp) 140 { 141 if (fp) 142 fp->flags &= ~FPROBE_FL_DISABLED; 143 } 144 145 /* The entry data size is 4 bits (=16) * sizeof(long) in maximum */ 146 #define FPROBE_DATA_SIZE_BITS 4 147 #define MAX_FPROBE_DATA_SIZE_WORD ((1L << FPROBE_DATA_SIZE_BITS) - 1) 148 #define MAX_FPROBE_DATA_SIZE (MAX_FPROBE_DATA_SIZE_WORD * sizeof(long)) 149 150 #endif 151