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* Kernel Probes (KProbes)
* include/linux/kprobes.h
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
* Copyright (C) IBM Corporation, 2002, 2004
* 2002-Oct Created by Vamsi Krishna S <> Kernel
* Probes initial implementation ( includes suggestions from
* Rusty Russell).
* 2004-July Suparna Bhattacharya <> added jumper probes
* interface to access function arguments.
* 2005-May Hien Nguyen <> and Jim Keniston
* <> and Prasanna S Panchamukhi
* <> added function-return probes.
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/smp.h>
#include <linux/percpu.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/mutex.h>
#include <asm/kprobes.h>
/* kprobe_status settings */
#define KPROBE_HIT_ACTIVE 0x00000001
#define KPROBE_HIT_SS 0x00000002
#define KPROBE_REENTER 0x00000004
#define KPROBE_HIT_SSDONE 0x00000008
/* Attach to insert probes on any functions which should be ignored*/
#define __kprobes __attribute__((__section__(".kprobes.text")))
struct kprobe;
struct pt_regs;
struct kretprobe;
struct kretprobe_instance;
typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
unsigned long flags);
typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
int trapnr);
typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
struct pt_regs *);
struct kprobe {
struct hlist_node hlist;
/* list of kprobes for multi-handler support */
struct list_head list;
/* Indicates that the corresponding module has been ref counted */
unsigned int mod_refcounted;
/*count the number of times this probe was temporarily disarmed */
unsigned long nmissed;
/* location of the probe point */
kprobe_opcode_t *addr;
/* Allow user to indicate symbol name of the probe point */
const char *symbol_name;
/* Offset into the symbol */
unsigned int offset;
/* Called before addr is executed. */
kprobe_pre_handler_t pre_handler;
/* Called after addr is executed, unless... */
kprobe_post_handler_t post_handler;
/* ... called if executing addr causes a fault (eg. page fault).
* Return 1 if it handled fault, otherwise kernel will see it. */
kprobe_fault_handler_t fault_handler;
/* ... called if breakpoint trap occurs in probe handler.
* Return 1 if it handled break, otherwise kernel will see it. */
kprobe_break_handler_t break_handler;
/* Saved opcode (which has been replaced with breakpoint) */
kprobe_opcode_t opcode;
/* copy of the original instruction */
struct arch_specific_insn ainsn;
* Special probe type that uses setjmp-longjmp type tricks to resume
* execution at a specified entry with a matching prototype corresponding
* to the probed function - a trick to enable arguments to become
* accessible seamlessly by probe handling logic.
* Note:
* Because of the way compilers allocate stack space for local variables
* etc upfront, regardless of sub-scopes within a function, this mirroring
* principle currently works only for probes placed on function entry points.
struct jprobe {
struct kprobe kp;
void *entry; /* probe handling code to jump to */
/* For backward compatibility with old code using JPROBE_ENTRY() */
#define JPROBE_ENTRY(handler) (handler)
DECLARE_PER_CPU(struct kprobe *, current_kprobe);
DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs);
extern int arch_trampoline_kprobe(struct kprobe *p);
static inline void arch_prepare_kretprobe(struct kretprobe *rp,
struct pt_regs *regs)
static inline int arch_trampoline_kprobe(struct kprobe *p)
return 0;
* Function-return probe -
* Note:
* User needs to provide a handler function, and initialize maxactive.
* maxactive - The maximum number of instances of the probed function that
* can be active concurrently.
* nmissed - tracks the number of times the probed function's return was
* ignored, due to maxactive being too low.
struct kretprobe {
struct kprobe kp;
kretprobe_handler_t handler;
kretprobe_handler_t entry_handler;
int maxactive;
int nmissed;
size_t data_size;
struct hlist_head free_instances;
struct hlist_head used_instances;
struct kretprobe_instance {
struct hlist_node uflist; /* either on free list or used list */
struct hlist_node hlist;
struct kretprobe *rp;
kprobe_opcode_t *ret_addr;
struct task_struct *task;
char data[0];
struct kretprobe_blackpoint {
const char *name;
void *addr;
extern struct kretprobe_blackpoint kretprobe_blacklist[];
static inline void kretprobe_assert(struct kretprobe_instance *ri,
unsigned long orig_ret_address, unsigned long trampoline_address)
if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
ri->rp, ri->rp->kp.addr);
extern int init_test_probes(void);
static inline int init_test_probes(void)
return 0;
extern spinlock_t kretprobe_lock;
extern struct mutex kprobe_mutex;
extern int arch_prepare_kprobe(struct kprobe *p);
extern void arch_arm_kprobe(struct kprobe *p);
extern void arch_disarm_kprobe(struct kprobe *p);
extern int arch_init_kprobes(void);
extern void show_registers(struct pt_regs *regs);
extern kprobe_opcode_t *get_insn_slot(void);
extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
extern void kprobes_inc_nmissed_count(struct kprobe *p);
/* Get the kprobe at this addr (if any) - called with preemption disabled */
struct kprobe *get_kprobe(void *addr);
struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
/* kprobe_running() will just return the current_kprobe on this CPU */
static inline struct kprobe *kprobe_running(void)
return (__get_cpu_var(current_kprobe));
static inline void reset_current_kprobe(void)
__get_cpu_var(current_kprobe) = NULL;
static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
return (&__get_cpu_var(kprobe_ctlblk));
int register_kprobe(struct kprobe *p);
void unregister_kprobe(struct kprobe *p);
int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
int longjmp_break_handler(struct kprobe *, struct pt_regs *);
int register_jprobe(struct jprobe *p);
void unregister_jprobe(struct jprobe *p);
void jprobe_return(void);
unsigned long arch_deref_entry_point(void *);
int register_kretprobe(struct kretprobe *rp);
void unregister_kretprobe(struct kretprobe *rp);
void kprobe_flush_task(struct task_struct *tk);
void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
#else /* CONFIG_KPROBES */
#define __kprobes /**/
struct jprobe;
struct kretprobe;
static inline struct kprobe *kprobe_running(void)
return NULL;
static inline int register_kprobe(struct kprobe *p)
return -ENOSYS;
static inline void unregister_kprobe(struct kprobe *p)
static inline int register_jprobe(struct jprobe *p)
return -ENOSYS;
static inline void unregister_jprobe(struct jprobe *p)
static inline void jprobe_return(void)
static inline int register_kretprobe(struct kretprobe *rp)
return -ENOSYS;
static inline void unregister_kretprobe(struct kretprobe *rp)
static inline void kprobe_flush_task(struct task_struct *tk)
#endif /* CONFIG_KPROBES */
#endif /* _LINUX_KPROBES_H */