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/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"))) 52 #else /* CONFIG_KPROBES */ 53 typedef int kprobe_opcode_t; 54 struct arch_specific_insn { 55 int dummy; 56 }; 57 #define __kprobes 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 /* 98 * ... called if executing addr causes a fault (eg. page fault). 99 * Return 1 if it handled fault, otherwise kernel will see it. 100 */ 101 kprobe_fault_handler_t fault_handler; 102 103 /* 104 * ... called if breakpoint trap occurs in probe handler. 105 * Return 1 if it handled break, otherwise kernel will see it. 106 */ 107 kprobe_break_handler_t break_handler; 108 109 /* Saved opcode (which has been replaced with breakpoint) */ 110 kprobe_opcode_t opcode; 111 112 /* copy of the original instruction */ 113 struct arch_specific_insn ainsn; 114 115 /* 116 * Indicates various status flags. 117 * Protected by kprobe_mutex after this kprobe is registered. 118 */ 119 u32 flags; 120 }; 121 122 /* Kprobe status flags */ 123 #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */ 124 #define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */ 125 #define KPROBE_FLAG_OPTIMIZED 4 /* 126 * probe is really optimized. 127 * NOTE: 128 * this flag is only for optimized_kprobe. 129 */ 130 131 /* Has this kprobe gone ? */ 132 static inline int kprobe_gone(struct kprobe *p) 133 { 134 return p->flags & KPROBE_FLAG_GONE; 135 } 136 137 /* Is this kprobe disabled ? */ 138 static inline int kprobe_disabled(struct kprobe *p) 139 { 140 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE); 141 } 142 143 /* Is this kprobe really running optimized path ? */ 144 static inline int kprobe_optimized(struct kprobe *p) 145 { 146 return p->flags & KPROBE_FLAG_OPTIMIZED; 147 } 148 /* 149 * Special probe type that uses setjmp-longjmp type tricks to resume 150 * execution at a specified entry with a matching prototype corresponding 151 * to the probed function - a trick to enable arguments to become 152 * accessible seamlessly by probe handling logic. 153 * Note: 154 * Because of the way compilers allocate stack space for local variables 155 * etc upfront, regardless of sub-scopes within a function, this mirroring 156 * principle currently works only for probes placed on function entry points. 157 */ 158 struct jprobe { 159 struct kprobe kp; 160 void *entry; /* probe handling code to jump to */ 161 }; 162 163 /* For backward compatibility with old code using JPROBE_ENTRY() */ 164 #define JPROBE_ENTRY(handler) (handler) 165 166 /* 167 * Function-return probe - 168 * Note: 169 * User needs to provide a handler function, and initialize maxactive. 170 * maxactive - The maximum number of instances of the probed function that 171 * can be active concurrently. 172 * nmissed - tracks the number of times the probed function's return was 173 * ignored, due to maxactive being too low. 174 * 175 */ 176 struct kretprobe { 177 struct kprobe kp; 178 kretprobe_handler_t handler; 179 kretprobe_handler_t entry_handler; 180 int maxactive; 181 int nmissed; 182 size_t data_size; 183 struct hlist_head free_instances; 184 spinlock_t lock; 185 }; 186 187 struct kretprobe_instance { 188 struct hlist_node hlist; 189 struct kretprobe *rp; 190 kprobe_opcode_t *ret_addr; 191 struct task_struct *task; 192 char data[0]; 193 }; 194 195 struct kretprobe_blackpoint { 196 const char *name; 197 void *addr; 198 }; 199 200 struct kprobe_blackpoint { 201 const char *name; 202 unsigned long start_addr; 203 unsigned long range; 204 }; 205 206 #ifdef CONFIG_KPROBES 207 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 208 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 209 210 /* 211 * For #ifdef avoidance: 212 */ 213 static inline int kprobes_built_in(void) 214 { 215 return 1; 216 } 217 218 #ifdef CONFIG_KRETPROBES 219 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 220 struct pt_regs *regs); 221 extern int arch_trampoline_kprobe(struct kprobe *p); 222 #else /* CONFIG_KRETPROBES */ 223 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 224 struct pt_regs *regs) 225 { 226 } 227 static inline int arch_trampoline_kprobe(struct kprobe *p) 228 { 229 return 0; 230 } 231 #endif /* CONFIG_KRETPROBES */ 232 233 extern struct kretprobe_blackpoint kretprobe_blacklist[]; 234 235 static inline void kretprobe_assert(struct kretprobe_instance *ri, 236 unsigned long orig_ret_address, unsigned long trampoline_address) 237 { 238 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 239 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 240 ri->rp, ri->rp->kp.addr); 241 BUG(); 242 } 243 } 244 245 #ifdef CONFIG_KPROBES_SANITY_TEST 246 extern int init_test_probes(void); 247 #else 248 static inline int init_test_probes(void) 249 { 250 return 0; 251 } 252 #endif /* CONFIG_KPROBES_SANITY_TEST */ 253 254 extern int arch_prepare_kprobe(struct kprobe *p); 255 extern void arch_arm_kprobe(struct kprobe *p); 256 extern void arch_disarm_kprobe(struct kprobe *p); 257 extern int arch_init_kprobes(void); 258 extern void show_registers(struct pt_regs *regs); 259 extern kprobe_opcode_t *get_insn_slot(void); 260 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty); 261 extern void kprobes_inc_nmissed_count(struct kprobe *p); 262 263 #ifdef CONFIG_OPTPROBES 264 /* 265 * Internal structure for direct jump optimized probe 266 */ 267 struct optimized_kprobe { 268 struct kprobe kp; 269 struct list_head list; /* list for optimizing queue */ 270 struct arch_optimized_insn optinsn; 271 }; 272 273 /* Architecture dependent functions for direct jump optimization */ 274 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn); 275 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op); 276 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op); 277 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op); 278 extern int arch_optimize_kprobe(struct optimized_kprobe *op); 279 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op); 280 extern kprobe_opcode_t *get_optinsn_slot(void); 281 extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty); 282 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op, 283 unsigned long addr); 284 285 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs); 286 287 #ifdef CONFIG_SYSCTL 288 extern int sysctl_kprobes_optimization; 289 extern int proc_kprobes_optimization_handler(struct ctl_table *table, 290 int write, void __user *buffer, 291 size_t *length, loff_t *ppos); 292 #endif 293 294 #endif /* CONFIG_OPTPROBES */ 295 296 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 297 struct kprobe *get_kprobe(void *addr); 298 void kretprobe_hash_lock(struct task_struct *tsk, 299 struct hlist_head **head, unsigned long *flags); 300 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags); 301 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 302 303 /* kprobe_running() will just return the current_kprobe on this CPU */ 304 static inline struct kprobe *kprobe_running(void) 305 { 306 return (__get_cpu_var(current_kprobe)); 307 } 308 309 static inline void reset_current_kprobe(void) 310 { 311 __get_cpu_var(current_kprobe) = NULL; 312 } 313 314 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 315 { 316 return (&__get_cpu_var(kprobe_ctlblk)); 317 } 318 319 int register_kprobe(struct kprobe *p); 320 void unregister_kprobe(struct kprobe *p); 321 int register_kprobes(struct kprobe **kps, int num); 322 void unregister_kprobes(struct kprobe **kps, int num); 323 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 324 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 325 int register_jprobe(struct jprobe *p); 326 void unregister_jprobe(struct jprobe *p); 327 int register_jprobes(struct jprobe **jps, int num); 328 void unregister_jprobes(struct jprobe **jps, int num); 329 void jprobe_return(void); 330 unsigned long arch_deref_entry_point(void *); 331 332 int register_kretprobe(struct kretprobe *rp); 333 void unregister_kretprobe(struct kretprobe *rp); 334 int register_kretprobes(struct kretprobe **rps, int num); 335 void unregister_kretprobes(struct kretprobe **rps, int num); 336 337 void kprobe_flush_task(struct task_struct *tk); 338 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 339 340 int disable_kprobe(struct kprobe *kp); 341 int enable_kprobe(struct kprobe *kp); 342 343 void dump_kprobe(struct kprobe *kp); 344 345 #else /* !CONFIG_KPROBES: */ 346 347 static inline int kprobes_built_in(void) 348 { 349 return 0; 350 } 351 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) 352 { 353 return 0; 354 } 355 static inline struct kprobe *get_kprobe(void *addr) 356 { 357 return NULL; 358 } 359 static inline struct kprobe *kprobe_running(void) 360 { 361 return NULL; 362 } 363 static inline int register_kprobe(struct kprobe *p) 364 { 365 return -ENOSYS; 366 } 367 static inline int register_kprobes(struct kprobe **kps, int num) 368 { 369 return -ENOSYS; 370 } 371 static inline void unregister_kprobe(struct kprobe *p) 372 { 373 } 374 static inline void unregister_kprobes(struct kprobe **kps, int num) 375 { 376 } 377 static inline int register_jprobe(struct jprobe *p) 378 { 379 return -ENOSYS; 380 } 381 static inline int register_jprobes(struct jprobe **jps, int num) 382 { 383 return -ENOSYS; 384 } 385 static inline void unregister_jprobe(struct jprobe *p) 386 { 387 } 388 static inline void unregister_jprobes(struct jprobe **jps, int num) 389 { 390 } 391 static inline void jprobe_return(void) 392 { 393 } 394 static inline int register_kretprobe(struct kretprobe *rp) 395 { 396 return -ENOSYS; 397 } 398 static inline int register_kretprobes(struct kretprobe **rps, int num) 399 { 400 return -ENOSYS; 401 } 402 static inline void unregister_kretprobe(struct kretprobe *rp) 403 { 404 } 405 static inline void unregister_kretprobes(struct kretprobe **rps, int num) 406 { 407 } 408 static inline void kprobe_flush_task(struct task_struct *tk) 409 { 410 } 411 static inline int disable_kprobe(struct kprobe *kp) 412 { 413 return -ENOSYS; 414 } 415 static inline int enable_kprobe(struct kprobe *kp) 416 { 417 return -ENOSYS; 418 } 419 #endif /* CONFIG_KPROBES */ 420 static inline int disable_kretprobe(struct kretprobe *rp) 421 { 422 return disable_kprobe(&rp->kp); 423 } 424 static inline int enable_kretprobe(struct kretprobe *rp) 425 { 426 return enable_kprobe(&rp->kp); 427 } 428 static inline int disable_jprobe(struct jprobe *jp) 429 { 430 return disable_kprobe(&jp->kp); 431 } 432 static inline int enable_jprobe(struct jprobe *jp) 433 { 434 return enable_kprobe(&jp->kp); 435 } 436 437 #endif /* _LINUX_KPROBES_H */ 438