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 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 /* Saved opcode (which has been replaced with breakpoint) */ 104 kprobe_opcode_t opcode; 105 106 /* copy of the original instruction */ 107 struct arch_specific_insn ainsn; 108 109 /* 110 * Indicates various status flags. 111 * Protected by kprobe_mutex after this kprobe is registered. 112 */ 113 u32 flags; 114 }; 115 116 /* Kprobe status flags */ 117 #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */ 118 #define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */ 119 #define KPROBE_FLAG_OPTIMIZED 4 /* 120 * probe is really optimized. 121 * NOTE: 122 * this flag is only for optimized_kprobe. 123 */ 124 #define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */ 125 126 /* Has this kprobe gone ? */ 127 static inline int kprobe_gone(struct kprobe *p) 128 { 129 return p->flags & KPROBE_FLAG_GONE; 130 } 131 132 /* Is this kprobe disabled ? */ 133 static inline int kprobe_disabled(struct kprobe *p) 134 { 135 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE); 136 } 137 138 /* Is this kprobe really running optimized path ? */ 139 static inline int kprobe_optimized(struct kprobe *p) 140 { 141 return p->flags & KPROBE_FLAG_OPTIMIZED; 142 } 143 144 /* Is this kprobe uses ftrace ? */ 145 static inline int kprobe_ftrace(struct kprobe *p) 146 { 147 return p->flags & KPROBE_FLAG_FTRACE; 148 } 149 150 /* 151 * Function-return probe - 152 * Note: 153 * User needs to provide a handler function, and initialize maxactive. 154 * maxactive - The maximum number of instances of the probed function that 155 * can be active concurrently. 156 * nmissed - tracks the number of times the probed function's return was 157 * ignored, due to maxactive being too low. 158 * 159 */ 160 struct kretprobe { 161 struct kprobe kp; 162 kretprobe_handler_t handler; 163 kretprobe_handler_t entry_handler; 164 int maxactive; 165 int nmissed; 166 size_t data_size; 167 struct hlist_head free_instances; 168 raw_spinlock_t lock; 169 }; 170 171 struct kretprobe_instance { 172 struct hlist_node hlist; 173 struct kretprobe *rp; 174 kprobe_opcode_t *ret_addr; 175 struct task_struct *task; 176 char data[0]; 177 }; 178 179 struct kretprobe_blackpoint { 180 const char *name; 181 void *addr; 182 }; 183 184 struct kprobe_blacklist_entry { 185 struct list_head list; 186 unsigned long start_addr; 187 unsigned long end_addr; 188 }; 189 190 #ifdef CONFIG_KPROBES 191 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 192 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 193 194 /* 195 * For #ifdef avoidance: 196 */ 197 static inline int kprobes_built_in(void) 198 { 199 return 1; 200 } 201 202 #ifdef CONFIG_KRETPROBES 203 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 204 struct pt_regs *regs); 205 extern int arch_trampoline_kprobe(struct kprobe *p); 206 #else /* CONFIG_KRETPROBES */ 207 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 208 struct pt_regs *regs) 209 { 210 } 211 static inline int arch_trampoline_kprobe(struct kprobe *p) 212 { 213 return 0; 214 } 215 #endif /* CONFIG_KRETPROBES */ 216 217 extern struct kretprobe_blackpoint kretprobe_blacklist[]; 218 219 static inline void kretprobe_assert(struct kretprobe_instance *ri, 220 unsigned long orig_ret_address, unsigned long trampoline_address) 221 { 222 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 223 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 224 ri->rp, ri->rp->kp.addr); 225 BUG(); 226 } 227 } 228 229 #ifdef CONFIG_KPROBES_SANITY_TEST 230 extern int init_test_probes(void); 231 #else 232 static inline int init_test_probes(void) 233 { 234 return 0; 235 } 236 #endif /* CONFIG_KPROBES_SANITY_TEST */ 237 238 extern int arch_prepare_kprobe(struct kprobe *p); 239 extern void arch_arm_kprobe(struct kprobe *p); 240 extern void arch_disarm_kprobe(struct kprobe *p); 241 extern int arch_init_kprobes(void); 242 extern void show_registers(struct pt_regs *regs); 243 extern void kprobes_inc_nmissed_count(struct kprobe *p); 244 extern bool arch_within_kprobe_blacklist(unsigned long addr); 245 extern int arch_populate_kprobe_blacklist(void); 246 extern bool arch_kprobe_on_func_entry(unsigned long offset); 247 extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset); 248 249 extern bool within_kprobe_blacklist(unsigned long addr); 250 extern int kprobe_add_ksym_blacklist(unsigned long entry); 251 extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end); 252 253 struct kprobe_insn_cache { 254 struct mutex mutex; 255 void *(*alloc)(void); /* allocate insn page */ 256 void (*free)(void *); /* free insn page */ 257 struct list_head pages; /* list of kprobe_insn_page */ 258 size_t insn_size; /* size of instruction slot */ 259 int nr_garbage; 260 }; 261 262 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT 263 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c); 264 extern void __free_insn_slot(struct kprobe_insn_cache *c, 265 kprobe_opcode_t *slot, int dirty); 266 /* sleep-less address checking routine */ 267 extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c, 268 unsigned long addr); 269 270 #define DEFINE_INSN_CACHE_OPS(__name) \ 271 extern struct kprobe_insn_cache kprobe_##__name##_slots; \ 272 \ 273 static inline kprobe_opcode_t *get_##__name##_slot(void) \ 274 { \ 275 return __get_insn_slot(&kprobe_##__name##_slots); \ 276 } \ 277 \ 278 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\ 279 { \ 280 __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \ 281 } \ 282 \ 283 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \ 284 { \ 285 return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \ 286 } 287 #else /* __ARCH_WANT_KPROBES_INSN_SLOT */ 288 #define DEFINE_INSN_CACHE_OPS(__name) \ 289 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \ 290 { \ 291 return 0; \ 292 } 293 #endif 294 295 DEFINE_INSN_CACHE_OPS(insn); 296 297 #ifdef CONFIG_OPTPROBES 298 /* 299 * Internal structure for direct jump optimized probe 300 */ 301 struct optimized_kprobe { 302 struct kprobe kp; 303 struct list_head list; /* list for optimizing queue */ 304 struct arch_optimized_insn optinsn; 305 }; 306 307 /* Architecture dependent functions for direct jump optimization */ 308 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn); 309 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op); 310 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, 311 struct kprobe *orig); 312 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op); 313 extern void arch_optimize_kprobes(struct list_head *oplist); 314 extern void arch_unoptimize_kprobes(struct list_head *oplist, 315 struct list_head *done_list); 316 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op); 317 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op, 318 unsigned long addr); 319 320 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs); 321 322 DEFINE_INSN_CACHE_OPS(optinsn); 323 324 #ifdef CONFIG_SYSCTL 325 extern int sysctl_kprobes_optimization; 326 extern int proc_kprobes_optimization_handler(struct ctl_table *table, 327 int write, void __user *buffer, 328 size_t *length, loff_t *ppos); 329 #endif 330 extern void wait_for_kprobe_optimizer(void); 331 #else 332 static inline void wait_for_kprobe_optimizer(void) { } 333 #endif /* CONFIG_OPTPROBES */ 334 #ifdef CONFIG_KPROBES_ON_FTRACE 335 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, 336 struct ftrace_ops *ops, struct pt_regs *regs); 337 extern int arch_prepare_kprobe_ftrace(struct kprobe *p); 338 #endif 339 340 int arch_check_ftrace_location(struct kprobe *p); 341 342 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 343 struct kprobe *get_kprobe(void *addr); 344 void kretprobe_hash_lock(struct task_struct *tsk, 345 struct hlist_head **head, unsigned long *flags); 346 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags); 347 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 348 349 /* kprobe_running() will just return the current_kprobe on this CPU */ 350 static inline struct kprobe *kprobe_running(void) 351 { 352 return (__this_cpu_read(current_kprobe)); 353 } 354 355 static inline void reset_current_kprobe(void) 356 { 357 __this_cpu_write(current_kprobe, NULL); 358 } 359 360 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 361 { 362 return this_cpu_ptr(&kprobe_ctlblk); 363 } 364 365 kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset); 366 int register_kprobe(struct kprobe *p); 367 void unregister_kprobe(struct kprobe *p); 368 int register_kprobes(struct kprobe **kps, int num); 369 void unregister_kprobes(struct kprobe **kps, int num); 370 unsigned long arch_deref_entry_point(void *); 371 372 int register_kretprobe(struct kretprobe *rp); 373 void unregister_kretprobe(struct kretprobe *rp); 374 int register_kretprobes(struct kretprobe **rps, int num); 375 void unregister_kretprobes(struct kretprobe **rps, int num); 376 377 void kprobe_flush_task(struct task_struct *tk); 378 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 379 380 int disable_kprobe(struct kprobe *kp); 381 int enable_kprobe(struct kprobe *kp); 382 383 void dump_kprobe(struct kprobe *kp); 384 385 void *alloc_insn_page(void); 386 void free_insn_page(void *page); 387 388 #else /* !CONFIG_KPROBES: */ 389 390 static inline int kprobes_built_in(void) 391 { 392 return 0; 393 } 394 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) 395 { 396 return 0; 397 } 398 static inline struct kprobe *get_kprobe(void *addr) 399 { 400 return NULL; 401 } 402 static inline struct kprobe *kprobe_running(void) 403 { 404 return NULL; 405 } 406 static inline int register_kprobe(struct kprobe *p) 407 { 408 return -ENOSYS; 409 } 410 static inline int register_kprobes(struct kprobe **kps, int num) 411 { 412 return -ENOSYS; 413 } 414 static inline void unregister_kprobe(struct kprobe *p) 415 { 416 } 417 static inline void unregister_kprobes(struct kprobe **kps, int num) 418 { 419 } 420 static inline int register_kretprobe(struct kretprobe *rp) 421 { 422 return -ENOSYS; 423 } 424 static inline int register_kretprobes(struct kretprobe **rps, int num) 425 { 426 return -ENOSYS; 427 } 428 static inline void unregister_kretprobe(struct kretprobe *rp) 429 { 430 } 431 static inline void unregister_kretprobes(struct kretprobe **rps, int num) 432 { 433 } 434 static inline void kprobe_flush_task(struct task_struct *tk) 435 { 436 } 437 static inline int disable_kprobe(struct kprobe *kp) 438 { 439 return -ENOSYS; 440 } 441 static inline int enable_kprobe(struct kprobe *kp) 442 { 443 return -ENOSYS; 444 } 445 446 static inline bool within_kprobe_blacklist(unsigned long addr) 447 { 448 return true; 449 } 450 #endif /* CONFIG_KPROBES */ 451 static inline int disable_kretprobe(struct kretprobe *rp) 452 { 453 return disable_kprobe(&rp->kp); 454 } 455 static inline int enable_kretprobe(struct kretprobe *rp) 456 { 457 return enable_kprobe(&rp->kp); 458 } 459 460 #ifndef CONFIG_KPROBES 461 static inline bool is_kprobe_insn_slot(unsigned long addr) 462 { 463 return false; 464 } 465 #endif 466 #ifndef CONFIG_OPTPROBES 467 static inline bool is_kprobe_optinsn_slot(unsigned long addr) 468 { 469 return false; 470 } 471 #endif 472 473 #endif /* _LINUX_KPROBES_H */ 474