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