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/list.h> 33 #include <linux/notifier.h> 34 #include <linux/smp.h> 35 #include <linux/percpu.h> 36 #include <linux/spinlock.h> 37 #include <linux/rcupdate.h> 38 #include <linux/mutex.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 /* Indicates that the corresponding module has been ref counted */ 72 unsigned int mod_refcounted; 73 74 /*count the number of times this probe was temporarily disarmed */ 75 unsigned long nmissed; 76 77 /* location of the probe point */ 78 kprobe_opcode_t *addr; 79 80 /* Called before addr is executed. */ 81 kprobe_pre_handler_t pre_handler; 82 83 /* Called after addr is executed, unless... */ 84 kprobe_post_handler_t post_handler; 85 86 /* ... called if executing addr causes a fault (eg. page fault). 87 * Return 1 if it handled fault, otherwise kernel will see it. */ 88 kprobe_fault_handler_t fault_handler; 89 90 /* ... called if breakpoint trap occurs in probe handler. 91 * Return 1 if it handled break, otherwise kernel will see it. */ 92 kprobe_break_handler_t break_handler; 93 94 /* Saved opcode (which has been replaced with breakpoint) */ 95 kprobe_opcode_t opcode; 96 97 /* copy of the original instruction */ 98 struct arch_specific_insn ainsn; 99 }; 100 101 /* 102 * Special probe type that uses setjmp-longjmp type tricks to resume 103 * execution at a specified entry with a matching prototype corresponding 104 * to the probed function - a trick to enable arguments to become 105 * accessible seamlessly by probe handling logic. 106 * Note: 107 * Because of the way compilers allocate stack space for local variables 108 * etc upfront, regardless of sub-scopes within a function, this mirroring 109 * principle currently works only for probes placed on function entry points. 110 */ 111 struct jprobe { 112 struct kprobe kp; 113 kprobe_opcode_t *entry; /* probe handling code to jump to */ 114 }; 115 116 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 117 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 118 119 #ifdef ARCH_SUPPORTS_KRETPROBES 120 extern void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs); 121 #else /* ARCH_SUPPORTS_KRETPROBES */ 122 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 123 struct pt_regs *regs) 124 { 125 } 126 #endif /* ARCH_SUPPORTS_KRETPROBES */ 127 /* 128 * Function-return probe - 129 * Note: 130 * User needs to provide a handler function, and initialize maxactive. 131 * maxactive - The maximum number of instances of the probed function that 132 * can be active concurrently. 133 * nmissed - tracks the number of times the probed function's return was 134 * ignored, due to maxactive being too low. 135 * 136 */ 137 struct kretprobe { 138 struct kprobe kp; 139 kretprobe_handler_t handler; 140 int maxactive; 141 int nmissed; 142 struct hlist_head free_instances; 143 struct hlist_head used_instances; 144 }; 145 146 struct kretprobe_instance { 147 struct hlist_node uflist; /* either on free list or used list */ 148 struct hlist_node hlist; 149 struct kretprobe *rp; 150 kprobe_opcode_t *ret_addr; 151 struct task_struct *task; 152 }; 153 154 extern spinlock_t kretprobe_lock; 155 extern struct mutex kprobe_mutex; 156 extern int arch_prepare_kprobe(struct kprobe *p); 157 extern void arch_arm_kprobe(struct kprobe *p); 158 extern void arch_disarm_kprobe(struct kprobe *p); 159 extern int arch_init_kprobes(void); 160 extern void show_registers(struct pt_regs *regs); 161 extern kprobe_opcode_t *get_insn_slot(void); 162 extern void free_insn_slot(kprobe_opcode_t *slot); 163 extern void kprobes_inc_nmissed_count(struct kprobe *p); 164 165 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 166 struct kprobe *get_kprobe(void *addr); 167 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 168 169 /* kprobe_running() will just return the current_kprobe on this CPU */ 170 static inline struct kprobe *kprobe_running(void) 171 { 172 return (__get_cpu_var(current_kprobe)); 173 } 174 175 static inline void reset_current_kprobe(void) 176 { 177 __get_cpu_var(current_kprobe) = NULL; 178 } 179 180 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 181 { 182 return (&__get_cpu_var(kprobe_ctlblk)); 183 } 184 185 int register_kprobe(struct kprobe *p); 186 void unregister_kprobe(struct kprobe *p); 187 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 188 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 189 int register_jprobe(struct jprobe *p); 190 void unregister_jprobe(struct jprobe *p); 191 void jprobe_return(void); 192 193 int register_kretprobe(struct kretprobe *rp); 194 void unregister_kretprobe(struct kretprobe *rp); 195 196 struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp); 197 void add_rp_inst(struct kretprobe_instance *ri); 198 void kprobe_flush_task(struct task_struct *tk); 199 void recycle_rp_inst(struct kretprobe_instance *ri); 200 #else /* CONFIG_KPROBES */ 201 202 #define __kprobes /**/ 203 struct jprobe; 204 struct kretprobe; 205 206 static inline struct kprobe *kprobe_running(void) 207 { 208 return NULL; 209 } 210 static inline int register_kprobe(struct kprobe *p) 211 { 212 return -ENOSYS; 213 } 214 static inline void unregister_kprobe(struct kprobe *p) 215 { 216 } 217 static inline int register_jprobe(struct jprobe *p) 218 { 219 return -ENOSYS; 220 } 221 static inline void unregister_jprobe(struct jprobe *p) 222 { 223 } 224 static inline void jprobe_return(void) 225 { 226 } 227 static inline int register_kretprobe(struct kretprobe *rp) 228 { 229 return -ENOSYS; 230 } 231 static inline void unregister_kretprobe(struct kretprobe *rp) 232 { 233 } 234 static inline void kprobe_flush_task(struct task_struct *tk) 235 { 236 } 237 #endif /* CONFIG_KPROBES */ 238 #endif /* _LINUX_KPROBES_H */ 239