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 <[email protected]> Kernel 24 * Probes initial implementation ( includes suggestions from 25 * Rusty Russell). 26 * 2004-July Suparna Bhattacharya <[email protected]> added jumper probes 27 * interface to access function arguments. 28 * 2005-May Hien Nguyen <[email protected]> and Jim Keniston 29 * <[email protected]> and Prasanna S Panchamukhi 30 * <[email protected]> added function-return probes. 31 */ 32 #include <linux/linkage.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"))) notrace 52 #else /* CONFIG_KPROBES */ 53 typedef int kprobe_opcode_t; 54 struct arch_specific_insn { 55 int dummy; 56 }; 57 #define __kprobes notrace 58 #endif /* CONFIG_KPROBES */ 59 60 struct kprobe; 61 struct pt_regs; 62 struct kretprobe; 63 struct kretprobe_instance; 64 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *); 65 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *); 66 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *, 67 unsigned long flags); 68 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *, 69 int trapnr); 70 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *, 71 struct pt_regs *); 72 73 struct kprobe { 74 struct hlist_node hlist; 75 76 /* list of kprobes for multi-handler support */ 77 struct list_head list; 78 79 /*count the number of times this probe was temporarily disarmed */ 80 unsigned long nmissed; 81 82 /* location of the probe point */ 83 kprobe_opcode_t *addr; 84 85 /* Allow user to indicate symbol name of the probe point */ 86 const char *symbol_name; 87 88 /* Offset into the symbol */ 89 unsigned int offset; 90 91 /* Called before addr is executed. */ 92 kprobe_pre_handler_t pre_handler; 93 94 /* Called after addr is executed, unless... */ 95 kprobe_post_handler_t post_handler; 96 97 /* ... called if executing addr causes a fault (eg. page fault). 98 * Return 1 if it handled fault, otherwise kernel will see it. */ 99 kprobe_fault_handler_t fault_handler; 100 101 /* ... called if breakpoint trap occurs in probe handler. 102 * Return 1 if it handled break, otherwise kernel will see it. */ 103 kprobe_break_handler_t break_handler; 104 105 /* Saved opcode (which has been replaced with breakpoint) */ 106 kprobe_opcode_t opcode; 107 108 /* copy of the original instruction */ 109 struct arch_specific_insn ainsn; 110 111 /* Indicates various status flags. Protected by kprobe_mutex. */ 112 u32 flags; 113 }; 114 115 /* Kprobe status flags */ 116 #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */ 117 118 static inline int kprobe_gone(struct kprobe *p) 119 { 120 return p->flags & KPROBE_FLAG_GONE; 121 } 122 123 /* 124 * Special probe type that uses setjmp-longjmp type tricks to resume 125 * execution at a specified entry with a matching prototype corresponding 126 * to the probed function - a trick to enable arguments to become 127 * accessible seamlessly by probe handling logic. 128 * Note: 129 * Because of the way compilers allocate stack space for local variables 130 * etc upfront, regardless of sub-scopes within a function, this mirroring 131 * principle currently works only for probes placed on function entry points. 132 */ 133 struct jprobe { 134 struct kprobe kp; 135 void *entry; /* probe handling code to jump to */ 136 }; 137 138 /* For backward compatibility with old code using JPROBE_ENTRY() */ 139 #define JPROBE_ENTRY(handler) (handler) 140 141 /* 142 * Function-return probe - 143 * Note: 144 * User needs to provide a handler function, and initialize maxactive. 145 * maxactive - The maximum number of instances of the probed function that 146 * can be active concurrently. 147 * nmissed - tracks the number of times the probed function's return was 148 * ignored, due to maxactive being too low. 149 * 150 */ 151 struct kretprobe { 152 struct kprobe kp; 153 kretprobe_handler_t handler; 154 kretprobe_handler_t entry_handler; 155 int maxactive; 156 int nmissed; 157 size_t data_size; 158 struct hlist_head free_instances; 159 spinlock_t lock; 160 }; 161 162 struct kretprobe_instance { 163 struct hlist_node hlist; 164 struct kretprobe *rp; 165 kprobe_opcode_t *ret_addr; 166 struct task_struct *task; 167 char data[0]; 168 }; 169 170 struct kretprobe_blackpoint { 171 const char *name; 172 void *addr; 173 }; 174 175 struct kprobe_blackpoint { 176 const char *name; 177 unsigned long start_addr; 178 unsigned long range; 179 }; 180 181 #ifdef CONFIG_KPROBES 182 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 183 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 184 185 #ifdef CONFIG_KRETPROBES 186 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 187 struct pt_regs *regs); 188 extern int arch_trampoline_kprobe(struct kprobe *p); 189 #else /* CONFIG_KRETPROBES */ 190 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 191 struct pt_regs *regs) 192 { 193 } 194 static inline int arch_trampoline_kprobe(struct kprobe *p) 195 { 196 return 0; 197 } 198 #endif /* CONFIG_KRETPROBES */ 199 200 extern struct kretprobe_blackpoint kretprobe_blacklist[]; 201 202 static inline void kretprobe_assert(struct kretprobe_instance *ri, 203 unsigned long orig_ret_address, unsigned long trampoline_address) 204 { 205 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 206 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 207 ri->rp, ri->rp->kp.addr); 208 BUG(); 209 } 210 } 211 212 #ifdef CONFIG_KPROBES_SANITY_TEST 213 extern int init_test_probes(void); 214 #else 215 static inline int init_test_probes(void) 216 { 217 return 0; 218 } 219 #endif /* CONFIG_KPROBES_SANITY_TEST */ 220 221 extern int arch_prepare_kprobe(struct kprobe *p); 222 extern void arch_arm_kprobe(struct kprobe *p); 223 extern void arch_disarm_kprobe(struct kprobe *p); 224 extern int arch_init_kprobes(void); 225 extern void show_registers(struct pt_regs *regs); 226 extern kprobe_opcode_t *get_insn_slot(void); 227 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty); 228 extern void kprobes_inc_nmissed_count(struct kprobe *p); 229 230 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 231 struct kprobe *get_kprobe(void *addr); 232 void kretprobe_hash_lock(struct task_struct *tsk, 233 struct hlist_head **head, unsigned long *flags); 234 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags); 235 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 236 237 /* kprobe_running() will just return the current_kprobe on this CPU */ 238 static inline struct kprobe *kprobe_running(void) 239 { 240 return (__get_cpu_var(current_kprobe)); 241 } 242 243 static inline void reset_current_kprobe(void) 244 { 245 __get_cpu_var(current_kprobe) = NULL; 246 } 247 248 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 249 { 250 return (&__get_cpu_var(kprobe_ctlblk)); 251 } 252 253 int register_kprobe(struct kprobe *p); 254 void unregister_kprobe(struct kprobe *p); 255 int register_kprobes(struct kprobe **kps, int num); 256 void unregister_kprobes(struct kprobe **kps, int num); 257 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 258 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 259 int register_jprobe(struct jprobe *p); 260 void unregister_jprobe(struct jprobe *p); 261 int register_jprobes(struct jprobe **jps, int num); 262 void unregister_jprobes(struct jprobe **jps, int num); 263 void jprobe_return(void); 264 unsigned long arch_deref_entry_point(void *); 265 266 int register_kretprobe(struct kretprobe *rp); 267 void unregister_kretprobe(struct kretprobe *rp); 268 int register_kretprobes(struct kretprobe **rps, int num); 269 void unregister_kretprobes(struct kretprobe **rps, int num); 270 271 void kprobe_flush_task(struct task_struct *tk); 272 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 273 274 #else /* CONFIG_KPROBES */ 275 276 static inline struct kprobe *get_kprobe(void *addr) 277 { 278 return NULL; 279 } 280 static inline struct kprobe *kprobe_running(void) 281 { 282 return NULL; 283 } 284 static inline int register_kprobe(struct kprobe *p) 285 { 286 return -ENOSYS; 287 } 288 static inline int register_kprobes(struct kprobe **kps, int num) 289 { 290 return -ENOSYS; 291 } 292 static inline void unregister_kprobe(struct kprobe *p) 293 { 294 } 295 static inline void unregister_kprobes(struct kprobe **kps, int num) 296 { 297 } 298 static inline int register_jprobe(struct jprobe *p) 299 { 300 return -ENOSYS; 301 } 302 static inline int register_jprobes(struct jprobe **jps, int num) 303 { 304 return -ENOSYS; 305 } 306 static inline void unregister_jprobe(struct jprobe *p) 307 { 308 } 309 static inline void unregister_jprobes(struct jprobe **jps, int num) 310 { 311 } 312 static inline void jprobe_return(void) 313 { 314 } 315 static inline int register_kretprobe(struct kretprobe *rp) 316 { 317 return -ENOSYS; 318 } 319 static inline int register_kretprobes(struct kretprobe **rps, int num) 320 { 321 return -ENOSYS; 322 } 323 static inline void unregister_kretprobe(struct kretprobe *rp) 324 { 325 } 326 static inline void unregister_kretprobes(struct kretprobe **rps, int num) 327 { 328 } 329 static inline void kprobe_flush_task(struct task_struct *tk) 330 { 331 } 332 #endif /* CONFIG_KPROBES */ 333 #endif /* _LINUX_KPROBES_H */ 334