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/compiler.h> 33 #include <linux/linkage.h> 34 #include <linux/list.h> 35 #include <linux/notifier.h> 36 #include <linux/smp.h> 37 #include <linux/bug.h> 38 #include <linux/percpu.h> 39 #include <linux/spinlock.h> 40 #include <linux/rcupdate.h> 41 #include <linux/mutex.h> 42 #include <linux/ftrace.h> 43 #include <asm/kprobes.h> 44 45 #ifdef CONFIG_KPROBES 46 47 /* kprobe_status settings */ 48 #define KPROBE_HIT_ACTIVE 0x00000001 49 #define KPROBE_HIT_SS 0x00000002 50 #define KPROBE_REENTER 0x00000004 51 #define KPROBE_HIT_SSDONE 0x00000008 52 53 #else /* CONFIG_KPROBES */ 54 #include <asm-generic/kprobes.h> 55 typedef int kprobe_opcode_t; 56 struct arch_specific_insn { 57 int dummy; 58 }; 59 #endif /* CONFIG_KPROBES */ 60 61 struct kprobe; 62 struct pt_regs; 63 struct kretprobe; 64 struct kretprobe_instance; 65 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *); 66 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *); 67 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *, 68 unsigned long flags); 69 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *, 70 int trapnr); 71 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *, 72 struct pt_regs *); 73 74 struct kprobe { 75 struct hlist_node hlist; 76 77 /* list of kprobes for multi-handler support */ 78 struct list_head list; 79 80 /*count the number of times this probe was temporarily disarmed */ 81 unsigned long nmissed; 82 83 /* location of the probe point */ 84 kprobe_opcode_t *addr; 85 86 /* Allow user to indicate symbol name of the probe point */ 87 const char *symbol_name; 88 89 /* Offset into the symbol */ 90 unsigned int offset; 91 92 /* Called before addr is executed. */ 93 kprobe_pre_handler_t pre_handler; 94 95 /* Called after addr is executed, unless... */ 96 kprobe_post_handler_t post_handler; 97 98 /* 99 * ... called if executing addr causes a fault (eg. page fault). 100 * Return 1 if it handled fault, otherwise kernel will see it. 101 */ 102 kprobe_fault_handler_t fault_handler; 103 104 /* 105 * ... called if breakpoint trap occurs in probe handler. 106 * Return 1 if it handled break, otherwise kernel will see it. 107 */ 108 kprobe_break_handler_t break_handler; 109 110 /* Saved opcode (which has been replaced with breakpoint) */ 111 kprobe_opcode_t opcode; 112 113 /* copy of the original instruction */ 114 struct arch_specific_insn ainsn; 115 116 /* 117 * Indicates various status flags. 118 * Protected by kprobe_mutex after this kprobe is registered. 119 */ 120 u32 flags; 121 }; 122 123 /* Kprobe status flags */ 124 #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */ 125 #define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */ 126 #define KPROBE_FLAG_OPTIMIZED 4 /* 127 * probe is really optimized. 128 * NOTE: 129 * this flag is only for optimized_kprobe. 130 */ 131 #define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */ 132 133 /* Has this kprobe gone ? */ 134 static inline int kprobe_gone(struct kprobe *p) 135 { 136 return p->flags & KPROBE_FLAG_GONE; 137 } 138 139 /* Is this kprobe disabled ? */ 140 static inline int kprobe_disabled(struct kprobe *p) 141 { 142 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE); 143 } 144 145 /* Is this kprobe really running optimized path ? */ 146 static inline int kprobe_optimized(struct kprobe *p) 147 { 148 return p->flags & KPROBE_FLAG_OPTIMIZED; 149 } 150 151 /* Is this kprobe uses ftrace ? */ 152 static inline int kprobe_ftrace(struct kprobe *p) 153 { 154 return p->flags & KPROBE_FLAG_FTRACE; 155 } 156 157 /* 158 * Special probe type that uses setjmp-longjmp type tricks to resume 159 * execution at a specified entry with a matching prototype corresponding 160 * to the probed function - a trick to enable arguments to become 161 * accessible seamlessly by probe handling logic. 162 * Note: 163 * Because of the way compilers allocate stack space for local variables 164 * etc upfront, regardless of sub-scopes within a function, this mirroring 165 * principle currently works only for probes placed on function entry points. 166 */ 167 struct jprobe { 168 struct kprobe kp; 169 void *entry; /* probe handling code to jump to */ 170 }; 171 172 /* For backward compatibility with old code using JPROBE_ENTRY() */ 173 #define JPROBE_ENTRY(handler) (handler) 174 175 /* 176 * Function-return probe - 177 * Note: 178 * User needs to provide a handler function, and initialize maxactive. 179 * maxactive - The maximum number of instances of the probed function that 180 * can be active concurrently. 181 * nmissed - tracks the number of times the probed function's return was 182 * ignored, due to maxactive being too low. 183 * 184 */ 185 struct kretprobe { 186 struct kprobe kp; 187 kretprobe_handler_t handler; 188 kretprobe_handler_t entry_handler; 189 int maxactive; 190 int nmissed; 191 size_t data_size; 192 struct hlist_head free_instances; 193 raw_spinlock_t lock; 194 }; 195 196 struct kretprobe_instance { 197 struct hlist_node hlist; 198 struct kretprobe *rp; 199 kprobe_opcode_t *ret_addr; 200 struct task_struct *task; 201 char data[0]; 202 }; 203 204 struct kretprobe_blackpoint { 205 const char *name; 206 void *addr; 207 }; 208 209 struct kprobe_blacklist_entry { 210 struct list_head list; 211 unsigned long start_addr; 212 unsigned long end_addr; 213 }; 214 215 #ifdef CONFIG_KPROBES 216 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 217 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 218 219 /* 220 * For #ifdef avoidance: 221 */ 222 static inline int kprobes_built_in(void) 223 { 224 return 1; 225 } 226 227 #ifdef CONFIG_KRETPROBES 228 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 229 struct pt_regs *regs); 230 extern int arch_trampoline_kprobe(struct kprobe *p); 231 #else /* CONFIG_KRETPROBES */ 232 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 233 struct pt_regs *regs) 234 { 235 } 236 static inline int arch_trampoline_kprobe(struct kprobe *p) 237 { 238 return 0; 239 } 240 #endif /* CONFIG_KRETPROBES */ 241 242 extern struct kretprobe_blackpoint kretprobe_blacklist[]; 243 244 static inline void kretprobe_assert(struct kretprobe_instance *ri, 245 unsigned long orig_ret_address, unsigned long trampoline_address) 246 { 247 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 248 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 249 ri->rp, ri->rp->kp.addr); 250 BUG(); 251 } 252 } 253 254 #ifdef CONFIG_KPROBES_SANITY_TEST 255 extern int init_test_probes(void); 256 #else 257 static inline int init_test_probes(void) 258 { 259 return 0; 260 } 261 #endif /* CONFIG_KPROBES_SANITY_TEST */ 262 263 extern int arch_prepare_kprobe(struct kprobe *p); 264 extern void arch_arm_kprobe(struct kprobe *p); 265 extern void arch_disarm_kprobe(struct kprobe *p); 266 extern int arch_init_kprobes(void); 267 extern void show_registers(struct pt_regs *regs); 268 extern void kprobes_inc_nmissed_count(struct kprobe *p); 269 extern bool arch_within_kprobe_blacklist(unsigned long addr); 270 271 extern bool within_kprobe_blacklist(unsigned long addr); 272 273 struct kprobe_insn_cache { 274 struct mutex mutex; 275 void *(*alloc)(void); /* allocate insn page */ 276 void (*free)(void *); /* free insn page */ 277 struct list_head pages; /* list of kprobe_insn_page */ 278 size_t insn_size; /* size of instruction slot */ 279 int nr_garbage; 280 }; 281 282 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT 283 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c); 284 extern void __free_insn_slot(struct kprobe_insn_cache *c, 285 kprobe_opcode_t *slot, int dirty); 286 /* sleep-less address checking routine */ 287 extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c, 288 unsigned long addr); 289 290 #define DEFINE_INSN_CACHE_OPS(__name) \ 291 extern struct kprobe_insn_cache kprobe_##__name##_slots; \ 292 \ 293 static inline kprobe_opcode_t *get_##__name##_slot(void) \ 294 { \ 295 return __get_insn_slot(&kprobe_##__name##_slots); \ 296 } \ 297 \ 298 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\ 299 { \ 300 __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \ 301 } \ 302 \ 303 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \ 304 { \ 305 return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \ 306 } 307 #else /* __ARCH_WANT_KPROBES_INSN_SLOT */ 308 #define DEFINE_INSN_CACHE_OPS(__name) \ 309 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \ 310 { \ 311 return 0; \ 312 } 313 #endif 314 315 DEFINE_INSN_CACHE_OPS(insn); 316 317 #ifdef CONFIG_OPTPROBES 318 /* 319 * Internal structure for direct jump optimized probe 320 */ 321 struct optimized_kprobe { 322 struct kprobe kp; 323 struct list_head list; /* list for optimizing queue */ 324 struct arch_optimized_insn optinsn; 325 }; 326 327 /* Architecture dependent functions for direct jump optimization */ 328 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn); 329 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op); 330 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, 331 struct kprobe *orig); 332 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op); 333 extern void arch_optimize_kprobes(struct list_head *oplist); 334 extern void arch_unoptimize_kprobes(struct list_head *oplist, 335 struct list_head *done_list); 336 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op); 337 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op, 338 unsigned long addr); 339 340 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs); 341 342 DEFINE_INSN_CACHE_OPS(optinsn); 343 344 #ifdef CONFIG_SYSCTL 345 extern int sysctl_kprobes_optimization; 346 extern int proc_kprobes_optimization_handler(struct ctl_table *table, 347 int write, void __user *buffer, 348 size_t *length, loff_t *ppos); 349 #endif 350 #endif /* CONFIG_OPTPROBES */ 351 #ifdef CONFIG_KPROBES_ON_FTRACE 352 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, 353 struct ftrace_ops *ops, struct pt_regs *regs); 354 extern int arch_prepare_kprobe_ftrace(struct kprobe *p); 355 #endif 356 357 int arch_check_ftrace_location(struct kprobe *p); 358 359 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 360 struct kprobe *get_kprobe(void *addr); 361 void kretprobe_hash_lock(struct task_struct *tsk, 362 struct hlist_head **head, unsigned long *flags); 363 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags); 364 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 365 366 /* kprobe_running() will just return the current_kprobe on this CPU */ 367 static inline struct kprobe *kprobe_running(void) 368 { 369 return (__this_cpu_read(current_kprobe)); 370 } 371 372 static inline void reset_current_kprobe(void) 373 { 374 __this_cpu_write(current_kprobe, NULL); 375 } 376 377 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 378 { 379 return this_cpu_ptr(&kprobe_ctlblk); 380 } 381 382 int register_kprobe(struct kprobe *p); 383 void unregister_kprobe(struct kprobe *p); 384 int register_kprobes(struct kprobe **kps, int num); 385 void unregister_kprobes(struct kprobe **kps, int num); 386 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 387 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 388 int register_jprobe(struct jprobe *p); 389 void unregister_jprobe(struct jprobe *p); 390 int register_jprobes(struct jprobe **jps, int num); 391 void unregister_jprobes(struct jprobe **jps, int num); 392 void jprobe_return(void); 393 unsigned long arch_deref_entry_point(void *); 394 395 int register_kretprobe(struct kretprobe *rp); 396 void unregister_kretprobe(struct kretprobe *rp); 397 int register_kretprobes(struct kretprobe **rps, int num); 398 void unregister_kretprobes(struct kretprobe **rps, int num); 399 400 void kprobe_flush_task(struct task_struct *tk); 401 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 402 403 int disable_kprobe(struct kprobe *kp); 404 int enable_kprobe(struct kprobe *kp); 405 406 void dump_kprobe(struct kprobe *kp); 407 408 #else /* !CONFIG_KPROBES: */ 409 410 static inline int kprobes_built_in(void) 411 { 412 return 0; 413 } 414 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) 415 { 416 return 0; 417 } 418 static inline struct kprobe *get_kprobe(void *addr) 419 { 420 return NULL; 421 } 422 static inline struct kprobe *kprobe_running(void) 423 { 424 return NULL; 425 } 426 static inline int register_kprobe(struct kprobe *p) 427 { 428 return -ENOSYS; 429 } 430 static inline int register_kprobes(struct kprobe **kps, int num) 431 { 432 return -ENOSYS; 433 } 434 static inline void unregister_kprobe(struct kprobe *p) 435 { 436 } 437 static inline void unregister_kprobes(struct kprobe **kps, int num) 438 { 439 } 440 static inline int register_jprobe(struct jprobe *p) 441 { 442 return -ENOSYS; 443 } 444 static inline int register_jprobes(struct jprobe **jps, int num) 445 { 446 return -ENOSYS; 447 } 448 static inline void unregister_jprobe(struct jprobe *p) 449 { 450 } 451 static inline void unregister_jprobes(struct jprobe **jps, int num) 452 { 453 } 454 static inline void jprobe_return(void) 455 { 456 } 457 static inline int register_kretprobe(struct kretprobe *rp) 458 { 459 return -ENOSYS; 460 } 461 static inline int register_kretprobes(struct kretprobe **rps, int num) 462 { 463 return -ENOSYS; 464 } 465 static inline void unregister_kretprobe(struct kretprobe *rp) 466 { 467 } 468 static inline void unregister_kretprobes(struct kretprobe **rps, int num) 469 { 470 } 471 static inline void kprobe_flush_task(struct task_struct *tk) 472 { 473 } 474 static inline int disable_kprobe(struct kprobe *kp) 475 { 476 return -ENOSYS; 477 } 478 static inline int enable_kprobe(struct kprobe *kp) 479 { 480 return -ENOSYS; 481 } 482 #endif /* CONFIG_KPROBES */ 483 static inline int disable_kretprobe(struct kretprobe *rp) 484 { 485 return disable_kprobe(&rp->kp); 486 } 487 static inline int enable_kretprobe(struct kretprobe *rp) 488 { 489 return enable_kprobe(&rp->kp); 490 } 491 static inline int disable_jprobe(struct jprobe *jp) 492 { 493 return disable_kprobe(&jp->kp); 494 } 495 static inline int enable_jprobe(struct jprobe *jp) 496 { 497 return enable_kprobe(&jp->kp); 498 } 499 500 #ifndef CONFIG_KPROBES 501 static inline bool is_kprobe_insn_slot(unsigned long addr) 502 { 503 return false; 504 } 505 #endif 506 #ifndef CONFIG_OPTPROBES 507 static inline bool is_kprobe_optinsn_slot(unsigned long addr) 508 { 509 return false; 510 } 511 #endif 512 513 #endif /* _LINUX_KPROBES_H */ 514