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 /* Allow user to indicate symbol name of the probe point */ 81 const char *symbol_name; 82 83 /* Offset into the symbol */ 84 unsigned int offset; 85 86 /* Called before addr is executed. */ 87 kprobe_pre_handler_t pre_handler; 88 89 /* Called after addr is executed, unless... */ 90 kprobe_post_handler_t post_handler; 91 92 /* ... called if executing addr causes a fault (eg. page fault). 93 * Return 1 if it handled fault, otherwise kernel will see it. */ 94 kprobe_fault_handler_t fault_handler; 95 96 /* ... called if breakpoint trap occurs in probe handler. 97 * Return 1 if it handled break, otherwise kernel will see it. */ 98 kprobe_break_handler_t break_handler; 99 100 /* Saved opcode (which has been replaced with breakpoint) */ 101 kprobe_opcode_t opcode; 102 103 /* copy of the original instruction */ 104 struct arch_specific_insn ainsn; 105 }; 106 107 /* 108 * Special probe type that uses setjmp-longjmp type tricks to resume 109 * execution at a specified entry with a matching prototype corresponding 110 * to the probed function - a trick to enable arguments to become 111 * accessible seamlessly by probe handling logic. 112 * Note: 113 * Because of the way compilers allocate stack space for local variables 114 * etc upfront, regardless of sub-scopes within a function, this mirroring 115 * principle currently works only for probes placed on function entry points. 116 */ 117 struct jprobe { 118 struct kprobe kp; 119 kprobe_opcode_t *entry; /* probe handling code to jump to */ 120 }; 121 122 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 123 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 124 125 #ifdef ARCH_SUPPORTS_KRETPROBES 126 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 127 struct pt_regs *regs); 128 extern int arch_trampoline_kprobe(struct kprobe *p); 129 #else /* ARCH_SUPPORTS_KRETPROBES */ 130 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 131 struct pt_regs *regs) 132 { 133 } 134 static inline int arch_trampoline_kprobe(struct kprobe *p) 135 { 136 return 0; 137 } 138 #endif /* ARCH_SUPPORTS_KRETPROBES */ 139 /* 140 * Function-return probe - 141 * Note: 142 * User needs to provide a handler function, and initialize maxactive. 143 * maxactive - The maximum number of instances of the probed function that 144 * can be active concurrently. 145 * nmissed - tracks the number of times the probed function's return was 146 * ignored, due to maxactive being too low. 147 * 148 */ 149 struct kretprobe { 150 struct kprobe kp; 151 kretprobe_handler_t handler; 152 int maxactive; 153 int nmissed; 154 struct hlist_head free_instances; 155 struct hlist_head used_instances; 156 }; 157 158 struct kretprobe_instance { 159 struct hlist_node uflist; /* either on free list or used list */ 160 struct hlist_node hlist; 161 struct kretprobe *rp; 162 kprobe_opcode_t *ret_addr; 163 struct task_struct *task; 164 }; 165 166 static inline void kretprobe_assert(struct kretprobe_instance *ri, 167 unsigned long orig_ret_address, unsigned long trampoline_address) 168 { 169 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 170 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 171 ri->rp, ri->rp->kp.addr); 172 BUG(); 173 } 174 } 175 176 extern spinlock_t kretprobe_lock; 177 extern struct mutex kprobe_mutex; 178 extern int arch_prepare_kprobe(struct kprobe *p); 179 extern void arch_arm_kprobe(struct kprobe *p); 180 extern void arch_disarm_kprobe(struct kprobe *p); 181 extern int arch_init_kprobes(void); 182 extern void show_registers(struct pt_regs *regs); 183 extern kprobe_opcode_t *get_insn_slot(void); 184 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty); 185 extern void kprobes_inc_nmissed_count(struct kprobe *p); 186 187 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 188 struct kprobe *get_kprobe(void *addr); 189 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 190 191 /* kprobe_running() will just return the current_kprobe on this CPU */ 192 static inline struct kprobe *kprobe_running(void) 193 { 194 return (__get_cpu_var(current_kprobe)); 195 } 196 197 static inline void reset_current_kprobe(void) 198 { 199 __get_cpu_var(current_kprobe) = NULL; 200 } 201 202 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 203 { 204 return (&__get_cpu_var(kprobe_ctlblk)); 205 } 206 207 int register_kprobe(struct kprobe *p); 208 void unregister_kprobe(struct kprobe *p); 209 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 210 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 211 int register_jprobe(struct jprobe *p); 212 void unregister_jprobe(struct jprobe *p); 213 void jprobe_return(void); 214 215 int register_kretprobe(struct kretprobe *rp); 216 void unregister_kretprobe(struct kretprobe *rp); 217 218 void kprobe_flush_task(struct task_struct *tk); 219 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 220 #else /* CONFIG_KPROBES */ 221 222 #define __kprobes /**/ 223 struct jprobe; 224 struct kretprobe; 225 226 static inline struct kprobe *kprobe_running(void) 227 { 228 return NULL; 229 } 230 static inline int register_kprobe(struct kprobe *p) 231 { 232 return -ENOSYS; 233 } 234 static inline void unregister_kprobe(struct kprobe *p) 235 { 236 } 237 static inline int register_jprobe(struct jprobe *p) 238 { 239 return -ENOSYS; 240 } 241 static inline void unregister_jprobe(struct jprobe *p) 242 { 243 } 244 static inline void jprobe_return(void) 245 { 246 } 247 static inline int register_kretprobe(struct kretprobe *rp) 248 { 249 return -ENOSYS; 250 } 251 static inline void unregister_kretprobe(struct kretprobe *rp) 252 { 253 } 254 static inline void kprobe_flush_task(struct task_struct *tk) 255 { 256 } 257 #endif /* CONFIG_KPROBES */ 258 #endif /* _LINUX_KPROBES_H */ 259