include/linux/fprobe.h

   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/rethook.h>
   9
  10 struct fprobe;
  11
  12 typedef int (*fprobe_entry_cb)(struct fprobe *fp, unsigned long entry_ip,
  13                                unsigned long ret_ip, struct pt_regs *regs,
  14                                void *entry_data);
  15
  16 typedef void (*fprobe_exit_cb)(struct fprobe *fp, unsigned long entry_ip,
  17                                unsigned long ret_ip, struct pt_regs *regs,
  18                                void *entry_data);
  19
  20 /**
  21  * struct fprobe - ftrace based probe.
  22  * @ops: The ftrace_ops.
  23  * @nmissed: The counter for missing events.
  24  * @flags: The status flag.
  25  * @rethook: The rethook data structure. (internal data)
  26  * @entry_data_size: The private data storage size.
  27  * @nr_maxactive: The max number of active functions.
  28  * @entry_handler: The callback function for function entry.
  29  * @exit_handler: The callback function for function exit.
  30  */
  31 struct fprobe {
  32 #ifdef CONFIG_FUNCTION_TRACER
  33         /*
  34          * If CONFIG_FUNCTION_TRACER is not set, CONFIG_FPROBE is disabled too.
  35          * But user of fprobe may keep embedding the struct fprobe on their own
  36          * code. To avoid build error, this will keep the fprobe data structure
  37          * defined here, but remove ftrace_ops data structure.
  38          */
  39         struct ftrace_ops       ops;
  40 #endif
  41         unsigned long           nmissed;
  42         unsigned int            flags;
  43         struct rethook          *rethook;
  44         size_t                  entry_data_size;
  45         int                     nr_maxactive;
  46
  47         fprobe_entry_cb entry_handler;
  48         fprobe_exit_cb  exit_handler;
  49 };
  50
  51 /* This fprobe is soft-disabled. */
  52 #define FPROBE_FL_DISABLED      1
  53
  54 /*
  55  * This fprobe handler will be shared with kprobes.
  56  * This flag must be set before registering.
  57  */
  58 #define FPROBE_FL_KPROBE_SHARED 2
  59
  60 static inline bool fprobe_disabled(struct fprobe *fp)
  61 {
  62         return (fp) ? fp->flags & FPROBE_FL_DISABLED : false;
  63 }
  64
  65 static inline bool fprobe_shared_with_kprobes(struct fprobe *fp)
  66 {
  67         return (fp) ? fp->flags & FPROBE_FL_KPROBE_SHARED : false;
  68 }
  69
  70 #ifdef CONFIG_FPROBE
  71 int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter);
  72 int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num);
  73 int register_fprobe_syms(struct fprobe *fp, const char **syms, int num);
  74 int unregister_fprobe(struct fprobe *fp);
  75 bool fprobe_is_registered(struct fprobe *fp);
  76 #else
  77 static inline int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter)
  78 {
  79         return -EOPNOTSUPP;
  80 }
  81 static inline int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num)
  82 {
  83         return -EOPNOTSUPP;
  84 }
  85 static inline int register_fprobe_syms(struct fprobe *fp, const char **syms, int num)
  86 {
  87         return -EOPNOTSUPP;
  88 }
  89 static inline int unregister_fprobe(struct fprobe *fp)
  90 {
  91         return -EOPNOTSUPP;
  92 }
  93 static inline bool fprobe_is_registered(struct fprobe *fp)
  94 {
  95         return false;
  96 }
  97 #endif
  98
  99 /**
 100  * disable_fprobe() - Disable fprobe
 101  * @fp: The fprobe to be disabled.
 102  *
 103  * This will soft-disable @fp. Note that this doesn't remove the ftrace
 104  * hooks from the function entry.
 105  */
 106 static inline void disable_fprobe(struct fprobe *fp)
 107 {
 108         if (fp)
 109                 fp->flags |= FPROBE_FL_DISABLED;
 110 }
 111
 112 /**
 113  * enable_fprobe() - Enable fprobe
 114  * @fp: The fprobe to be enabled.
 115  *
 116  * This will soft-enable @fp.
 117  */
 118 static inline void enable_fprobe(struct fprobe *fp)
 119 {
 120         if (fp)
 121                 fp->flags &= ~FPROBE_FL_DISABLED;
 122 }
 123
 124 #endif