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> /* for __kprobes */ 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 44 #ifdef CONFIG_KPROBES 45 #include <asm/kprobes.h> 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 typedef int kprobe_opcode_t; 55 struct arch_specific_insn { 56 int dummy; 57 }; 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 #define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */ 131 132 /* Has this kprobe gone ? */ 133 static inline int kprobe_gone(struct kprobe *p) 134 { 135 return p->flags & KPROBE_FLAG_GONE; 136 } 137 138 /* Is this kprobe disabled ? */ 139 static inline int kprobe_disabled(struct kprobe *p) 140 { 141 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE); 142 } 143 144 /* Is this kprobe really running optimized path ? */ 145 static inline int kprobe_optimized(struct kprobe *p) 146 { 147 return p->flags & KPROBE_FLAG_OPTIMIZED; 148 } 149 150 /* Is this kprobe uses ftrace ? */ 151 static inline int kprobe_ftrace(struct kprobe *p) 152 { 153 return p->flags & KPROBE_FLAG_FTRACE; 154 } 155 156 /* 157 * Special probe type that uses setjmp-longjmp type tricks to resume 158 * execution at a specified entry with a matching prototype corresponding 159 * to the probed function - a trick to enable arguments to become 160 * accessible seamlessly by probe handling logic. 161 * Note: 162 * Because of the way compilers allocate stack space for local variables 163 * etc upfront, regardless of sub-scopes within a function, this mirroring 164 * principle currently works only for probes placed on function entry points. 165 */ 166 struct jprobe { 167 struct kprobe kp; 168 void *entry; /* probe handling code to jump to */ 169 }; 170 171 /* For backward compatibility with old code using JPROBE_ENTRY() */ 172 #define JPROBE_ENTRY(handler) (handler) 173 174 /* 175 * Function-return probe - 176 * Note: 177 * User needs to provide a handler function, and initialize maxactive. 178 * maxactive - The maximum number of instances of the probed function that 179 * can be active concurrently. 180 * nmissed - tracks the number of times the probed function's return was 181 * ignored, due to maxactive being too low. 182 * 183 */ 184 struct kretprobe { 185 struct kprobe kp; 186 kretprobe_handler_t handler; 187 kretprobe_handler_t entry_handler; 188 int maxactive; 189 int nmissed; 190 size_t data_size; 191 struct hlist_head free_instances; 192 raw_spinlock_t lock; 193 }; 194 195 struct kretprobe_instance { 196 struct hlist_node hlist; 197 struct kretprobe *rp; 198 kprobe_opcode_t *ret_addr; 199 struct task_struct *task; 200 char data[0]; 201 }; 202 203 struct kretprobe_blackpoint { 204 const char *name; 205 void *addr; 206 }; 207 208 struct kprobe_blacklist_entry { 209 struct list_head list; 210 unsigned long start_addr; 211 unsigned long end_addr; 212 }; 213 214 #ifdef CONFIG_KPROBES 215 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 216 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 217 218 /* 219 * For #ifdef avoidance: 220 */ 221 static inline int kprobes_built_in(void) 222 { 223 return 1; 224 } 225 226 #ifdef CONFIG_KRETPROBES 227 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 228 struct pt_regs *regs); 229 extern int arch_trampoline_kprobe(struct kprobe *p); 230 #else /* CONFIG_KRETPROBES */ 231 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 232 struct pt_regs *regs) 233 { 234 } 235 static inline int arch_trampoline_kprobe(struct kprobe *p) 236 { 237 return 0; 238 } 239 #endif /* CONFIG_KRETPROBES */ 240 241 extern struct kretprobe_blackpoint kretprobe_blacklist[]; 242 243 static inline void kretprobe_assert(struct kretprobe_instance *ri, 244 unsigned long orig_ret_address, unsigned long trampoline_address) 245 { 246 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 247 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 248 ri->rp, ri->rp->kp.addr); 249 BUG(); 250 } 251 } 252 253 #ifdef CONFIG_KPROBES_SANITY_TEST 254 extern int init_test_probes(void); 255 #else 256 static inline int init_test_probes(void) 257 { 258 return 0; 259 } 260 #endif /* CONFIG_KPROBES_SANITY_TEST */ 261 262 extern int arch_prepare_kprobe(struct kprobe *p); 263 extern void arch_arm_kprobe(struct kprobe *p); 264 extern void arch_disarm_kprobe(struct kprobe *p); 265 extern int arch_init_kprobes(void); 266 extern void show_registers(struct pt_regs *regs); 267 extern void kprobes_inc_nmissed_count(struct kprobe *p); 268 extern bool arch_within_kprobe_blacklist(unsigned long addr); 269 270 extern bool within_kprobe_blacklist(unsigned long addr); 271 272 struct kprobe_insn_cache { 273 struct mutex mutex; 274 void *(*alloc)(void); /* allocate insn page */ 275 void (*free)(void *); /* free insn page */ 276 struct list_head pages; /* list of kprobe_insn_page */ 277 size_t insn_size; /* size of instruction slot */ 278 int nr_garbage; 279 }; 280 281 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c); 282 extern void __free_insn_slot(struct kprobe_insn_cache *c, 283 kprobe_opcode_t *slot, int dirty); 284 285 #define DEFINE_INSN_CACHE_OPS(__name) \ 286 extern struct kprobe_insn_cache kprobe_##__name##_slots; \ 287 \ 288 static inline kprobe_opcode_t *get_##__name##_slot(void) \ 289 { \ 290 return __get_insn_slot(&kprobe_##__name##_slots); \ 291 } \ 292 \ 293 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\ 294 { \ 295 __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \ 296 } \ 297 298 DEFINE_INSN_CACHE_OPS(insn); 299 300 #ifdef CONFIG_OPTPROBES 301 /* 302 * Internal structure for direct jump optimized probe 303 */ 304 struct optimized_kprobe { 305 struct kprobe kp; 306 struct list_head list; /* list for optimizing queue */ 307 struct arch_optimized_insn optinsn; 308 }; 309 310 /* Architecture dependent functions for direct jump optimization */ 311 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn); 312 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op); 313 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, 314 struct kprobe *orig); 315 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op); 316 extern void arch_optimize_kprobes(struct list_head *oplist); 317 extern void arch_unoptimize_kprobes(struct list_head *oplist, 318 struct list_head *done_list); 319 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op); 320 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op, 321 unsigned long addr); 322 323 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs); 324 325 DEFINE_INSN_CACHE_OPS(optinsn); 326 327 #ifdef CONFIG_SYSCTL 328 extern int sysctl_kprobes_optimization; 329 extern int proc_kprobes_optimization_handler(struct ctl_table *table, 330 int write, void __user *buffer, 331 size_t *length, loff_t *ppos); 332 #endif 333 334 #endif /* CONFIG_OPTPROBES */ 335 #ifdef CONFIG_KPROBES_ON_FTRACE 336 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, 337 struct ftrace_ops *ops, struct pt_regs *regs); 338 extern int arch_prepare_kprobe_ftrace(struct kprobe *p); 339 #endif 340 341 int arch_check_ftrace_location(struct kprobe *p); 342 343 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 344 struct kprobe *get_kprobe(void *addr); 345 void kretprobe_hash_lock(struct task_struct *tsk, 346 struct hlist_head **head, unsigned long *flags); 347 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags); 348 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 349 350 /* kprobe_running() will just return the current_kprobe on this CPU */ 351 static inline struct kprobe *kprobe_running(void) 352 { 353 return (__this_cpu_read(current_kprobe)); 354 } 355 356 static inline void reset_current_kprobe(void) 357 { 358 __this_cpu_write(current_kprobe, NULL); 359 } 360 361 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 362 { 363 return this_cpu_ptr(&kprobe_ctlblk); 364 } 365 366 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 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 371 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 372 int register_jprobe(struct jprobe *p); 373 void unregister_jprobe(struct jprobe *p); 374 int register_jprobes(struct jprobe **jps, int num); 375 void unregister_jprobes(struct jprobe **jps, int num); 376 void jprobe_return(void); 377 unsigned long arch_deref_entry_point(void *); 378 379 int register_kretprobe(struct kretprobe *rp); 380 void unregister_kretprobe(struct kretprobe *rp); 381 int register_kretprobes(struct kretprobe **rps, int num); 382 void unregister_kretprobes(struct kretprobe **rps, int num); 383 384 void kprobe_flush_task(struct task_struct *tk); 385 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 386 387 int disable_kprobe(struct kprobe *kp); 388 int enable_kprobe(struct kprobe *kp); 389 390 void dump_kprobe(struct kprobe *kp); 391 392 #else /* !CONFIG_KPROBES: */ 393 394 static inline int kprobes_built_in(void) 395 { 396 return 0; 397 } 398 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) 399 { 400 return 0; 401 } 402 static inline struct kprobe *get_kprobe(void *addr) 403 { 404 return NULL; 405 } 406 static inline struct kprobe *kprobe_running(void) 407 { 408 return NULL; 409 } 410 static inline int register_kprobe(struct kprobe *p) 411 { 412 return -ENOSYS; 413 } 414 static inline int register_kprobes(struct kprobe **kps, int num) 415 { 416 return -ENOSYS; 417 } 418 static inline void unregister_kprobe(struct kprobe *p) 419 { 420 } 421 static inline void unregister_kprobes(struct kprobe **kps, int num) 422 { 423 } 424 static inline int register_jprobe(struct jprobe *p) 425 { 426 return -ENOSYS; 427 } 428 static inline int register_jprobes(struct jprobe **jps, int num) 429 { 430 return -ENOSYS; 431 } 432 static inline void unregister_jprobe(struct jprobe *p) 433 { 434 } 435 static inline void unregister_jprobes(struct jprobe **jps, int num) 436 { 437 } 438 static inline void jprobe_return(void) 439 { 440 } 441 static inline int register_kretprobe(struct kretprobe *rp) 442 { 443 return -ENOSYS; 444 } 445 static inline int register_kretprobes(struct kretprobe **rps, int num) 446 { 447 return -ENOSYS; 448 } 449 static inline void unregister_kretprobe(struct kretprobe *rp) 450 { 451 } 452 static inline void unregister_kretprobes(struct kretprobe **rps, int num) 453 { 454 } 455 static inline void kprobe_flush_task(struct task_struct *tk) 456 { 457 } 458 static inline int disable_kprobe(struct kprobe *kp) 459 { 460 return -ENOSYS; 461 } 462 static inline int enable_kprobe(struct kprobe *kp) 463 { 464 return -ENOSYS; 465 } 466 #endif /* CONFIG_KPROBES */ 467 static inline int disable_kretprobe(struct kretprobe *rp) 468 { 469 return disable_kprobe(&rp->kp); 470 } 471 static inline int enable_kretprobe(struct kretprobe *rp) 472 { 473 return enable_kprobe(&rp->kp); 474 } 475 static inline int disable_jprobe(struct jprobe *jp) 476 { 477 return disable_kprobe(&jp->kp); 478 } 479 static inline int enable_jprobe(struct jprobe *jp) 480 { 481 return enable_kprobe(&jp->kp); 482 } 483 484 #ifdef CONFIG_KPROBES 485 /* 486 * Blacklist ganerating macro. Specify functions which is not probed 487 * by using this macro. 488 */ 489 #define __NOKPROBE_SYMBOL(fname) \ 490 static unsigned long __used \ 491 __attribute__((section("_kprobe_blacklist"))) \ 492 _kbl_addr_##fname = (unsigned long)fname; 493 #define NOKPROBE_SYMBOL(fname) __NOKPROBE_SYMBOL(fname) 494 #else 495 #define NOKPROBE_SYMBOL(fname) 496 #endif 497 498 #endif /* _LINUX_KPROBES_H */ 499