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