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 #include <linux/percpu.h> 37 #include <linux/spinlock.h> 38 #include <linux/rcupdate.h> 39 40 #ifdef CONFIG_KPROBES 41 #include <asm/kprobes.h> 42 43 /* kprobe_status settings */ 44 #define KPROBE_HIT_ACTIVE 0x00000001 45 #define KPROBE_HIT_SS 0x00000002 46 #define KPROBE_REENTER 0x00000004 47 #define KPROBE_HIT_SSDONE 0x00000008 48 49 /* Attach to insert probes on any functions which should be ignored*/ 50 #define __kprobes __attribute__((__section__(".kprobes.text"))) 51 52 struct kprobe; 53 struct pt_regs; 54 struct kretprobe; 55 struct kretprobe_instance; 56 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *); 57 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *); 58 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *, 59 unsigned long flags); 60 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *, 61 int trapnr); 62 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *, 63 struct pt_regs *); 64 65 struct kprobe { 66 struct hlist_node hlist; 67 68 /* list of kprobes for multi-handler support */ 69 struct list_head list; 70 71 /*count the number of times this probe was temporarily disarmed */ 72 unsigned long nmissed; 73 74 /* location of the probe point */ 75 kprobe_opcode_t *addr; 76 77 /* Called before addr is executed. */ 78 kprobe_pre_handler_t pre_handler; 79 80 /* Called after addr is executed, unless... */ 81 kprobe_post_handler_t post_handler; 82 83 /* ... called if executing addr causes a fault (eg. page fault). 84 * Return 1 if it handled fault, otherwise kernel will see it. */ 85 kprobe_fault_handler_t fault_handler; 86 87 /* ... called if breakpoint trap occurs in probe handler. 88 * Return 1 if it handled break, otherwise kernel will see it. */ 89 kprobe_break_handler_t break_handler; 90 91 /* Saved opcode (which has been replaced with breakpoint) */ 92 kprobe_opcode_t opcode; 93 94 /* copy of the original instruction */ 95 struct arch_specific_insn ainsn; 96 }; 97 98 /* 99 * Special probe type that uses setjmp-longjmp type tricks to resume 100 * execution at a specified entry with a matching prototype corresponding 101 * to the probed function - a trick to enable arguments to become 102 * accessible seamlessly by probe handling logic. 103 * Note: 104 * Because of the way compilers allocate stack space for local variables 105 * etc upfront, regardless of sub-scopes within a function, this mirroring 106 * principle currently works only for probes placed on function entry points. 107 */ 108 struct jprobe { 109 struct kprobe kp; 110 kprobe_opcode_t *entry; /* probe handling code to jump to */ 111 }; 112 113 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 114 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 115 116 #ifdef ARCH_SUPPORTS_KRETPROBES 117 extern void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs); 118 #else /* ARCH_SUPPORTS_KRETPROBES */ 119 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 120 struct pt_regs *regs) 121 { 122 } 123 #endif /* ARCH_SUPPORTS_KRETPROBES */ 124 /* 125 * Function-return probe - 126 * Note: 127 * User needs to provide a handler function, and initialize maxactive. 128 * maxactive - The maximum number of instances of the probed function that 129 * can be active concurrently. 130 * nmissed - tracks the number of times the probed function's return was 131 * ignored, due to maxactive being too low. 132 * 133 */ 134 struct kretprobe { 135 struct kprobe kp; 136 kretprobe_handler_t handler; 137 int maxactive; 138 int nmissed; 139 struct hlist_head free_instances; 140 struct hlist_head used_instances; 141 }; 142 143 struct kretprobe_instance { 144 struct hlist_node uflist; /* either on free list or used list */ 145 struct hlist_node hlist; 146 struct kretprobe *rp; 147 kprobe_opcode_t *ret_addr; 148 struct task_struct *task; 149 }; 150 151 extern spinlock_t kretprobe_lock; 152 extern int arch_prepare_kprobe(struct kprobe *p); 153 extern void arch_copy_kprobe(struct kprobe *p); 154 extern void arch_arm_kprobe(struct kprobe *p); 155 extern void arch_disarm_kprobe(struct kprobe *p); 156 extern void arch_remove_kprobe(struct kprobe *p); 157 extern int arch_init_kprobes(void); 158 extern void show_registers(struct pt_regs *regs); 159 extern kprobe_opcode_t *get_insn_slot(void); 160 extern void free_insn_slot(kprobe_opcode_t *slot); 161 extern void kprobes_inc_nmissed_count(struct kprobe *p); 162 163 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 164 struct kprobe *get_kprobe(void *addr); 165 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 166 167 /* kprobe_running() will just return the current_kprobe on this CPU */ 168 static inline struct kprobe *kprobe_running(void) 169 { 170 return (__get_cpu_var(current_kprobe)); 171 } 172 173 static inline void reset_current_kprobe(void) 174 { 175 __get_cpu_var(current_kprobe) = NULL; 176 } 177 178 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 179 { 180 return (&__get_cpu_var(kprobe_ctlblk)); 181 } 182 183 int register_kprobe(struct kprobe *p); 184 void unregister_kprobe(struct kprobe *p); 185 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 186 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 187 int register_jprobe(struct jprobe *p); 188 void unregister_jprobe(struct jprobe *p); 189 void jprobe_return(void); 190 191 int register_kretprobe(struct kretprobe *rp); 192 void unregister_kretprobe(struct kretprobe *rp); 193 194 struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp); 195 void add_rp_inst(struct kretprobe_instance *ri); 196 void kprobe_flush_task(struct task_struct *tk); 197 void recycle_rp_inst(struct kretprobe_instance *ri); 198 #else /* CONFIG_KPROBES */ 199 200 #define __kprobes /**/ 201 struct jprobe; 202 struct kretprobe; 203 204 static inline struct kprobe *kprobe_running(void) 205 { 206 return NULL; 207 } 208 static inline int register_kprobe(struct kprobe *p) 209 { 210 return -ENOSYS; 211 } 212 static inline void unregister_kprobe(struct kprobe *p) 213 { 214 } 215 static inline int register_jprobe(struct jprobe *p) 216 { 217 return -ENOSYS; 218 } 219 static inline void unregister_jprobe(struct jprobe *p) 220 { 221 } 222 static inline void jprobe_return(void) 223 { 224 } 225 static inline int register_kretprobe(struct kretprobe *rp) 226 { 227 return -ENOSYS; 228 } 229 static inline void unregister_kretprobe(struct kretprobe *rp) 230 { 231 } 232 static inline void kprobe_flush_task(struct task_struct *tk) 233 { 234 } 235 #endif /* CONFIG_KPROBES */ 236 #endif /* _LINUX_KPROBES_H */ 237