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