include/linux/kprobes.h

   1 #ifndef _LINUX_KPROBES_H
   2 #define _LINUX_KPROBES_H
   3 /*
   4  *  Kernel Probes (KProbes)
   5  *  include/linux/kprobes.h
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20  *
  21  * Copyright (C) IBM Corporation, 2002, 2004
  22  *
  23  * 2002-Oct     Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
  24  *              Probes initial implementation ( includes suggestions from
  25  *              Rusty Russell).
  26  * 2004-July    Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
  27  *              interface to access function arguments.
  28  */
  29 #include <linux/config.h>
  30 #include <linux/list.h>
  31 #include <linux/notifier.h>
  32 #include <linux/smp.h>
  33 #include <asm/kprobes.h>
  34
  35 struct kprobe;
  36 struct pt_regs;
  37 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  38 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  39 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  40                                        unsigned long flags);
  41 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  42                                        int trapnr);
  43 struct kprobe {
  44         struct hlist_node hlist;
  45
  46         /* location of the probe point */
  47         kprobe_opcode_t *addr;
  48
  49         /* Called before addr is executed. */
  50         kprobe_pre_handler_t pre_handler;
  51
  52         /* Called after addr is executed, unless... */
  53         kprobe_post_handler_t post_handler;
  54
  55         /* ... called if executing addr causes a fault (eg. page fault).
  56          * Return 1 if it handled fault, otherwise kernel will see it. */
  57         kprobe_fault_handler_t fault_handler;
  58
  59         /* ... called if breakpoint trap occurs in probe handler.
  60          * Return 1 if it handled break, otherwise kernel will see it. */
  61         kprobe_break_handler_t break_handler;
  62
  63         /* Saved opcode (which has been replaced with breakpoint) */
  64         kprobe_opcode_t opcode;
  65
  66         /* copy of the original instruction */
  67         kprobe_opcode_t insn[MAX_INSN_SIZE];
  68 };
  69
  70 /*
  71  * Special probe type that uses setjmp-longjmp type tricks to resume
  72  * execution at a specified entry with a matching prototype corresponding
  73  * to the probed function - a trick to enable arguments to become
  74  * accessible seamlessly by probe handling logic.
  75  * Note:
  76  * Because of the way compilers allocate stack space for local variables
  77  * etc upfront, regardless of sub-scopes within a function, this mirroring
  78  * principle currently works only for probes placed on function entry points.
  79  */
  80 struct jprobe {
  81         struct kprobe kp;
  82         kprobe_opcode_t *entry; /* probe handling code to jump to */
  83 };
  84
  85 #ifdef CONFIG_KPROBES
  86 /* Locks kprobe: irq must be disabled */
  87 void lock_kprobes(void);
  88 void unlock_kprobes(void);
  89
  90 /* kprobe running now on this CPU? */
  91 static inline int kprobe_running(void)
  92 {
  93         extern unsigned int kprobe_cpu;
  94         return kprobe_cpu == smp_processor_id();
  95 }
  96
  97 extern void arch_prepare_kprobe(struct kprobe *p);
  98 extern void show_registers(struct pt_regs *regs);
  99
 100 /* Get the kprobe at this addr (if any).  Must have called lock_kprobes */
 101 struct kprobe *get_kprobe(void *addr);
 102
 103 int register_kprobe(struct kprobe *p);
 104 void unregister_kprobe(struct kprobe *p);
 105 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 106 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 107 int register_jprobe(struct jprobe *p);
 108 void unregister_jprobe(struct jprobe *p);
 109 void jprobe_return(void);
 110
 111 #else
 112 static inline int kprobe_running(void)
 113 {
 114         return 0;
 115 }
 116 static inline int register_kprobe(struct kprobe *p)
 117 {
 118         return -ENOSYS;
 119 }
 120 static inline void unregister_kprobe(struct kprobe *p)
 121 {
 122 }
 123 static inline int register_jprobe(struct jprobe *p)
 124 {
 125         return -ENOSYS;
 126 }
 127 static inline void unregister_jprobe(struct jprobe *p)
 128 {
 129 }
 130 static inline void jprobe_return(void)
 131 {
 132 }
 133 #endif
 134 #endif                          /* _LINUX_KPROBES_H */