#ifndef _LINUX_KPROBES_H #define _LINUX_KPROBES_H /* * 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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * 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 #include #include #include #include #include #include #ifdef CONFIG_KPROBES #include /* 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; /* 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; kprobe_opcode_t *entry; /* probe handling code to jump to */ }; DECLARE_PER_CPU(struct kprobe *, current_kprobe); DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); #ifdef ARCH_SUPPORTS_KRETPROBES extern void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs); #else /* ARCH_SUPPORTS_KRETPROBES */ static inline void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs) { } #endif /* ARCH_SUPPORTS_KRETPROBES */ /* * 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; int maxactive; int nmissed; 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; }; 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); 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); int register_kretprobe(struct kretprobe *rp); void unregister_kretprobe(struct kretprobe *rp); struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp); void add_rp_inst(struct kretprobe_instance *ri); void kprobe_flush_task(struct task_struct *tk); void recycle_rp_inst(struct kretprobe_instance *ri); #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 */