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  * 2005-May     Hien Nguyen <hien@us.ibm.com> and Jim Keniston
  29  *              <jkenisto@us.ibm.com>  and Prasanna S Panchamukhi
  30  *              <prasanna@in.ibm.com> added function-return probes.
  31  */
  32 #include <linux/config.h>
  33 #include <linux/list.h>
  34 #include <linux/notifier.h>
  35 #include <linux/smp.h>
  36
  37 #include <asm/kprobes.h>
  38
  39 /* kprobe_status settings */
  40 #define KPROBE_HIT_ACTIVE       0x00000001
  41 #define KPROBE_HIT_SS           0x00000002
  42 #define KPROBE_REENTER          0x00000004
  43 #define KPROBE_HIT_SSDONE       0x00000008
  44
  45 /* Attach to insert probes on any functions which should be ignored*/
  46 #define __kprobes       __attribute__((__section__(".kprobes.text")))
  47
  48 struct kprobe;
  49 struct pt_regs;
  50 struct kretprobe;
  51 struct kretprobe_instance;
  52 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  53 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  54 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  55                                        unsigned long flags);
  56 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  57                                        int trapnr);
  58 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
  59                                     struct pt_regs *);
  60
  61 struct kprobe {
  62         struct hlist_node hlist;
  63
  64         /* list of kprobes for multi-handler support */
  65         struct list_head list;
  66
  67         /*count the number of times this probe was temporarily disarmed */
  68         unsigned long nmissed;
  69
  70         /* location of the probe point */
  71         kprobe_opcode_t *addr;
  72
  73         /* Called before addr is executed. */
  74         kprobe_pre_handler_t pre_handler;
  75
  76         /* Called after addr is executed, unless... */
  77         kprobe_post_handler_t post_handler;
  78
  79         /* ... called if executing addr causes a fault (eg. page fault).
  80          * Return 1 if it handled fault, otherwise kernel will see it. */
  81         kprobe_fault_handler_t fault_handler;
  82
  83         /* ... called if breakpoint trap occurs in probe handler.
  84          * Return 1 if it handled break, otherwise kernel will see it. */
  85         kprobe_break_handler_t break_handler;
  86
  87         /* Saved opcode (which has been replaced with breakpoint) */
  88         kprobe_opcode_t opcode;
  89
  90         /* copy of the original instruction */
  91         struct arch_specific_insn ainsn;
  92 };
  93
  94 /*
  95  * Special probe type that uses setjmp-longjmp type tricks to resume
  96  * execution at a specified entry with a matching prototype corresponding
  97  * to the probed function - a trick to enable arguments to become
  98  * accessible seamlessly by probe handling logic.
  99  * Note:
 100  * Because of the way compilers allocate stack space for local variables
 101  * etc upfront, regardless of sub-scopes within a function, this mirroring
 102  * principle currently works only for probes placed on function entry points.
 103  */
 104 struct jprobe {
 105         struct kprobe kp;
 106         kprobe_opcode_t *entry; /* probe handling code to jump to */
 107 };
 108
 109 #ifdef ARCH_SUPPORTS_KRETPROBES
 110 extern void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs);
 111 #else /* ARCH_SUPPORTS_KRETPROBES */
 112 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 113                                         struct pt_regs *regs)
 114 {
 115 }
 116 #endif /* ARCH_SUPPORTS_KRETPROBES */
 117 /*
 118  * Function-return probe -
 119  * Note:
 120  * User needs to provide a handler function, and initialize maxactive.
 121  * maxactive - The maximum number of instances of the probed function that
 122  * can be active concurrently.
 123  * nmissed - tracks the number of times the probed function's return was
 124  * ignored, due to maxactive being too low.
 125  *
 126  */
 127 struct kretprobe {
 128         struct kprobe kp;
 129         kretprobe_handler_t handler;
 130         int maxactive;
 131         int nmissed;
 132         struct hlist_head free_instances;
 133         struct hlist_head used_instances;
 134 };
 135
 136 struct kretprobe_instance {
 137         struct hlist_node uflist; /* either on free list or used list */
 138         struct hlist_node hlist;
 139         struct kretprobe *rp;
 140         kprobe_opcode_t *ret_addr;
 141         struct task_struct *task;
 142 };
 143
 144 #ifdef CONFIG_KPROBES
 145 /* Locks kprobe: irq must be disabled */
 146 void lock_kprobes(void);
 147 void unlock_kprobes(void);
 148
 149 /* kprobe running now on this CPU? */
 150 static inline int kprobe_running(void)
 151 {
 152         extern unsigned int kprobe_cpu;
 153         return kprobe_cpu == smp_processor_id();
 154 }
 155
 156 extern int arch_prepare_kprobe(struct kprobe *p);
 157 extern void arch_copy_kprobe(struct kprobe *p);
 158 extern void arch_arm_kprobe(struct kprobe *p);
 159 extern void arch_disarm_kprobe(struct kprobe *p);
 160 extern void arch_remove_kprobe(struct kprobe *p);
 161 extern int arch_init_kprobes(void);
 162 extern void show_registers(struct pt_regs *regs);
 163 extern kprobe_opcode_t *get_insn_slot(void);
 164 extern void free_insn_slot(kprobe_opcode_t *slot);
 165
 166 /* Get the kprobe at this addr (if any).  Must have called lock_kprobes */
 167 struct kprobe *get_kprobe(void *addr);
 168 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 169
 170 int register_kprobe(struct kprobe *p);
 171 void unregister_kprobe(struct kprobe *p);
 172 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 173 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 174 int register_jprobe(struct jprobe *p);
 175 void unregister_jprobe(struct jprobe *p);
 176 void jprobe_return(void);
 177
 178 int register_kretprobe(struct kretprobe *rp);
 179 void unregister_kretprobe(struct kretprobe *rp);
 180
 181 struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp);
 182 void add_rp_inst(struct kretprobe_instance *ri);
 183 void kprobe_flush_task(struct task_struct *tk);
 184 void recycle_rp_inst(struct kretprobe_instance *ri);
 185 #else /* CONFIG_KPROBES */
 186 static inline int kprobe_running(void)
 187 {
 188         return 0;
 189 }
 190 static inline int register_kprobe(struct kprobe *p)
 191 {
 192         return -ENOSYS;
 193 }
 194 static inline void unregister_kprobe(struct kprobe *p)
 195 {
 196 }
 197 static inline int register_jprobe(struct jprobe *p)
 198 {
 199         return -ENOSYS;
 200 }
 201 static inline void unregister_jprobe(struct jprobe *p)
 202 {
 203 }
 204 static inline void jprobe_return(void)
 205 {
 206 }
 207 static inline int register_kretprobe(struct kretprobe *rp)
 208 {
 209         return -ENOSYS;
 210 }
 211 static inline void unregister_kretprobe(struct kretprobe *rp)
 212 {
 213 }
 214 static inline void kprobe_flush_task(struct task_struct *tk)
 215 {
 216 }
 217 #endif                          /* CONFIG_KPROBES */
 218 #endif                          /* _LINUX_KPROBES_H */