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 #include <linux/mutex.h> 40 41 #ifdef CONFIG_KPROBES 42 #include <asm/kprobes.h> 43 44 /* kprobe_status settings */ 45 #define KPROBE_HIT_ACTIVE 0x00000001 46 #define KPROBE_HIT_SS 0x00000002 47 #define KPROBE_REENTER 0x00000004 48 #define KPROBE_HIT_SSDONE 0x00000008 49 50 /* Attach to insert probes on any functions which should be ignored*/ 51 #define __kprobes __attribute__((__section__(".kprobes.text"))) 52 53 struct kprobe; 54 struct pt_regs; 55 struct kretprobe; 56 struct kretprobe_instance; 57 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *); 58 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *); 59 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *, 60 unsigned long flags); 61 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *, 62 int trapnr); 63 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *, 64 struct pt_regs *); 65 66 struct kprobe { 67 struct hlist_node hlist; 68 69 /* list of kprobes for multi-handler support */ 70 struct list_head list; 71 72 /* Indicates that the corresponding module has been ref counted */ 73 unsigned int mod_refcounted; 74 75 /*count the number of times this probe was temporarily disarmed */ 76 unsigned long nmissed; 77 78 /* location of the probe point */ 79 kprobe_opcode_t *addr; 80 81 /* Called before addr is executed. */ 82 kprobe_pre_handler_t pre_handler; 83 84 /* Called after addr is executed, unless... */ 85 kprobe_post_handler_t post_handler; 86 87 /* ... called if executing addr causes a fault (eg. page fault). 88 * Return 1 if it handled fault, otherwise kernel will see it. */ 89 kprobe_fault_handler_t fault_handler; 90 91 /* ... called if breakpoint trap occurs in probe handler. 92 * Return 1 if it handled break, otherwise kernel will see it. */ 93 kprobe_break_handler_t break_handler; 94 95 /* Saved opcode (which has been replaced with breakpoint) */ 96 kprobe_opcode_t opcode; 97 98 /* copy of the original instruction */ 99 struct arch_specific_insn ainsn; 100 }; 101 102 /* 103 * Special probe type that uses setjmp-longjmp type tricks to resume 104 * execution at a specified entry with a matching prototype corresponding 105 * to the probed function - a trick to enable arguments to become 106 * accessible seamlessly by probe handling logic. 107 * Note: 108 * Because of the way compilers allocate stack space for local variables 109 * etc upfront, regardless of sub-scopes within a function, this mirroring 110 * principle currently works only for probes placed on function entry points. 111 */ 112 struct jprobe { 113 struct kprobe kp; 114 kprobe_opcode_t *entry; /* probe handling code to jump to */ 115 }; 116 117 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 118 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 119 120 #ifdef ARCH_SUPPORTS_KRETPROBES 121 extern void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs); 122 #else /* ARCH_SUPPORTS_KRETPROBES */ 123 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 124 struct pt_regs *regs) 125 { 126 } 127 #endif /* ARCH_SUPPORTS_KRETPROBES */ 128 /* 129 * Function-return probe - 130 * Note: 131 * User needs to provide a handler function, and initialize maxactive. 132 * maxactive - The maximum number of instances of the probed function that 133 * can be active concurrently. 134 * nmissed - tracks the number of times the probed function's return was 135 * ignored, due to maxactive being too low. 136 * 137 */ 138 struct kretprobe { 139 struct kprobe kp; 140 kretprobe_handler_t handler; 141 int maxactive; 142 int nmissed; 143 struct hlist_head free_instances; 144 struct hlist_head used_instances; 145 }; 146 147 struct kretprobe_instance { 148 struct hlist_node uflist; /* either on free list or used list */ 149 struct hlist_node hlist; 150 struct kretprobe *rp; 151 kprobe_opcode_t *ret_addr; 152 struct task_struct *task; 153 }; 154 155 extern spinlock_t kretprobe_lock; 156 extern struct mutex kprobe_mutex; 157 extern int arch_prepare_kprobe(struct kprobe *p); 158 extern void arch_arm_kprobe(struct kprobe *p); 159 extern void arch_disarm_kprobe(struct kprobe *p); 160 extern int arch_init_kprobes(void); 161 extern void show_registers(struct pt_regs *regs); 162 extern kprobe_opcode_t *get_insn_slot(void); 163 extern void free_insn_slot(kprobe_opcode_t *slot); 164 extern void kprobes_inc_nmissed_count(struct kprobe *p); 165 166 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 167 struct kprobe *get_kprobe(void *addr); 168 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 169 170 /* kprobe_running() will just return the current_kprobe on this CPU */ 171 static inline struct kprobe *kprobe_running(void) 172 { 173 return (__get_cpu_var(current_kprobe)); 174 } 175 176 static inline void reset_current_kprobe(void) 177 { 178 __get_cpu_var(current_kprobe) = NULL; 179 } 180 181 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 182 { 183 return (&__get_cpu_var(kprobe_ctlblk)); 184 } 185 186 int register_kprobe(struct kprobe *p); 187 void unregister_kprobe(struct kprobe *p); 188 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 189 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 190 int register_jprobe(struct jprobe *p); 191 void unregister_jprobe(struct jprobe *p); 192 void jprobe_return(void); 193 194 int register_kretprobe(struct kretprobe *rp); 195 void unregister_kretprobe(struct kretprobe *rp); 196 197 struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp); 198 void add_rp_inst(struct kretprobe_instance *ri); 199 void kprobe_flush_task(struct task_struct *tk); 200 void recycle_rp_inst(struct kretprobe_instance *ri); 201 #else /* CONFIG_KPROBES */ 202 203 #define __kprobes /**/ 204 struct jprobe; 205 struct kretprobe; 206 207 static inline struct kprobe *kprobe_running(void) 208 { 209 return NULL; 210 } 211 static inline int register_kprobe(struct kprobe *p) 212 { 213 return -ENOSYS; 214 } 215 static inline void unregister_kprobe(struct kprobe *p) 216 { 217 } 218 static inline int register_jprobe(struct jprobe *p) 219 { 220 return -ENOSYS; 221 } 222 static inline void unregister_jprobe(struct jprobe *p) 223 { 224 } 225 static inline void jprobe_return(void) 226 { 227 } 228 static inline int register_kretprobe(struct kretprobe *rp) 229 { 230 return -ENOSYS; 231 } 232 static inline void unregister_kretprobe(struct kretprobe *rp) 233 { 234 } 235 static inline void kprobe_flush_task(struct task_struct *tk) 236 { 237 } 238 #endif /* CONFIG_KPROBES */ 239 #endif /* _LINUX_KPROBES_H */ 240