1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 #ifndef _LINUX_KPROBES_H 3 #define _LINUX_KPROBES_H 4 /* 5 * Kernel Probes (KProbes) 6 * include/linux/kprobes.h 7 * 8 * Copyright (C) IBM Corporation, 2002, 2004 9 * 10 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel 11 * Probes initial implementation ( includes suggestions from 12 * Rusty Russell). 13 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes 14 * interface to access function arguments. 15 * 2005-May Hien Nguyen <hien@us.ibm.com> and Jim Keniston 16 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi 17 * <prasanna@in.ibm.com> added function-return probes. 18 */ 19 #include <linux/compiler.h> 20 #include <linux/linkage.h> 21 #include <linux/list.h> 22 #include <linux/notifier.h> 23 #include <linux/smp.h> 24 #include <linux/bug.h> 25 #include <linux/percpu.h> 26 #include <linux/spinlock.h> 27 #include <linux/rcupdate.h> 28 #include <linux/mutex.h> 29 #include <linux/ftrace.h> 30 #include <asm/kprobes.h> 31 32 #ifdef CONFIG_KPROBES 33 34 /* kprobe_status settings */ 35 #define KPROBE_HIT_ACTIVE 0x00000001 36 #define KPROBE_HIT_SS 0x00000002 37 #define KPROBE_REENTER 0x00000004 38 #define KPROBE_HIT_SSDONE 0x00000008 39 40 #else /* CONFIG_KPROBES */ 41 #include <asm-generic/kprobes.h> 42 typedef int kprobe_opcode_t; 43 struct arch_specific_insn { 44 int dummy; 45 }; 46 #endif /* CONFIG_KPROBES */ 47 48 struct kprobe; 49 struct pt_regs; 50 struct kretprobe; 51 struct kretprobe_instance; 52 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *); 53 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *, 54 unsigned long flags); 55 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *, 56 int trapnr); 57 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *, 58 struct pt_regs *); 59 60 struct kprobe { 61 struct hlist_node hlist; 62 63 /* list of kprobes for multi-handler support */ 64 struct list_head list; 65 66 /*count the number of times this probe was temporarily disarmed */ 67 unsigned long nmissed; 68 69 /* location of the probe point */ 70 kprobe_opcode_t *addr; 71 72 /* Allow user to indicate symbol name of the probe point */ 73 const char *symbol_name; 74 75 /* Offset into the symbol */ 76 unsigned int offset; 77 78 /* Called before addr is executed. */ 79 kprobe_pre_handler_t pre_handler; 80 81 /* Called after addr is executed, unless... */ 82 kprobe_post_handler_t post_handler; 83 84 /* 85 * ... called if executing addr causes a fault (eg. page fault). 86 * Return 1 if it handled fault, otherwise kernel will see it. 87 */ 88 kprobe_fault_handler_t fault_handler; 89 90 /* Saved opcode (which has been replaced with breakpoint) */ 91 kprobe_opcode_t opcode; 92 93 /* copy of the original instruction */ 94 struct arch_specific_insn ainsn; 95 96 /* 97 * Indicates various status flags. 98 * Protected by kprobe_mutex after this kprobe is registered. 99 */ 100 u32 flags; 101 }; 102 103 /* Kprobe status flags */ 104 #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */ 105 #define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */ 106 #define KPROBE_FLAG_OPTIMIZED 4 /* 107 * probe is really optimized. 108 * NOTE: 109 * this flag is only for optimized_kprobe. 110 */ 111 #define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */ 112 113 /* Has this kprobe gone ? */ 114 static inline int kprobe_gone(struct kprobe *p) 115 { 116 return p->flags & KPROBE_FLAG_GONE; 117 } 118 119 /* Is this kprobe disabled ? */ 120 static inline int kprobe_disabled(struct kprobe *p) 121 { 122 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE); 123 } 124 125 /* Is this kprobe really running optimized path ? */ 126 static inline int kprobe_optimized(struct kprobe *p) 127 { 128 return p->flags & KPROBE_FLAG_OPTIMIZED; 129 } 130 131 /* Is this kprobe uses ftrace ? */ 132 static inline int kprobe_ftrace(struct kprobe *p) 133 { 134 return p->flags & KPROBE_FLAG_FTRACE; 135 } 136 137 /* 138 * Function-return probe - 139 * Note: 140 * User needs to provide a handler function, and initialize maxactive. 141 * maxactive - The maximum number of instances of the probed function that 142 * can be active concurrently. 143 * nmissed - tracks the number of times the probed function's return was 144 * ignored, due to maxactive being too low. 145 * 146 */ 147 struct kretprobe { 148 struct kprobe kp; 149 kretprobe_handler_t handler; 150 kretprobe_handler_t entry_handler; 151 int maxactive; 152 int nmissed; 153 size_t data_size; 154 struct hlist_head free_instances; 155 raw_spinlock_t lock; 156 }; 157 158 struct kretprobe_instance { 159 struct hlist_node hlist; 160 struct kretprobe *rp; 161 kprobe_opcode_t *ret_addr; 162 struct task_struct *task; 163 void *fp; 164 char data[0]; 165 }; 166 167 struct kretprobe_blackpoint { 168 const char *name; 169 void *addr; 170 }; 171 172 struct kprobe_blacklist_entry { 173 struct list_head list; 174 unsigned long start_addr; 175 unsigned long end_addr; 176 }; 177 178 #ifdef CONFIG_KPROBES 179 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 180 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 181 182 /* 183 * For #ifdef avoidance: 184 */ 185 static inline int kprobes_built_in(void) 186 { 187 return 1; 188 } 189 190 #ifdef CONFIG_KRETPROBES 191 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 192 struct pt_regs *regs); 193 extern int arch_trampoline_kprobe(struct kprobe *p); 194 #else /* CONFIG_KRETPROBES */ 195 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 196 struct pt_regs *regs) 197 { 198 } 199 static inline int arch_trampoline_kprobe(struct kprobe *p) 200 { 201 return 0; 202 } 203 #endif /* CONFIG_KRETPROBES */ 204 205 extern struct kretprobe_blackpoint kretprobe_blacklist[]; 206 207 static inline void kretprobe_assert(struct kretprobe_instance *ri, 208 unsigned long orig_ret_address, unsigned long trampoline_address) 209 { 210 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 211 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 212 ri->rp, ri->rp->kp.addr); 213 BUG(); 214 } 215 } 216 217 #ifdef CONFIG_KPROBES_SANITY_TEST 218 extern int init_test_probes(void); 219 #else 220 static inline int init_test_probes(void) 221 { 222 return 0; 223 } 224 #endif /* CONFIG_KPROBES_SANITY_TEST */ 225 226 extern int arch_prepare_kprobe(struct kprobe *p); 227 extern void arch_arm_kprobe(struct kprobe *p); 228 extern void arch_disarm_kprobe(struct kprobe *p); 229 extern int arch_init_kprobes(void); 230 extern void show_registers(struct pt_regs *regs); 231 extern void kprobes_inc_nmissed_count(struct kprobe *p); 232 extern bool arch_within_kprobe_blacklist(unsigned long addr); 233 extern int arch_populate_kprobe_blacklist(void); 234 extern bool arch_kprobe_on_func_entry(unsigned long offset); 235 extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset); 236 237 extern bool within_kprobe_blacklist(unsigned long addr); 238 extern int kprobe_add_ksym_blacklist(unsigned long entry); 239 extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end); 240 241 struct kprobe_insn_cache { 242 struct mutex mutex; 243 void *(*alloc)(void); /* allocate insn page */ 244 void (*free)(void *); /* free insn page */ 245 struct list_head pages; /* list of kprobe_insn_page */ 246 size_t insn_size; /* size of instruction slot */ 247 int nr_garbage; 248 }; 249 250 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT 251 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c); 252 extern void __free_insn_slot(struct kprobe_insn_cache *c, 253 kprobe_opcode_t *slot, int dirty); 254 /* sleep-less address checking routine */ 255 extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c, 256 unsigned long addr); 257 258 #define DEFINE_INSN_CACHE_OPS(__name) \ 259 extern struct kprobe_insn_cache kprobe_##__name##_slots; \ 260 \ 261 static inline kprobe_opcode_t *get_##__name##_slot(void) \ 262 { \ 263 return __get_insn_slot(&kprobe_##__name##_slots); \ 264 } \ 265 \ 266 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\ 267 { \ 268 __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \ 269 } \ 270 \ 271 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \ 272 { \ 273 return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \ 274 } 275 #else /* __ARCH_WANT_KPROBES_INSN_SLOT */ 276 #define DEFINE_INSN_CACHE_OPS(__name) \ 277 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \ 278 { \ 279 return 0; \ 280 } 281 #endif 282 283 DEFINE_INSN_CACHE_OPS(insn); 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 struct kprobe *orig); 300 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op); 301 extern void arch_optimize_kprobes(struct list_head *oplist); 302 extern void arch_unoptimize_kprobes(struct list_head *oplist, 303 struct list_head *done_list); 304 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op); 305 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op, 306 unsigned long addr); 307 308 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs); 309 310 DEFINE_INSN_CACHE_OPS(optinsn); 311 312 #ifdef CONFIG_SYSCTL 313 extern int sysctl_kprobes_optimization; 314 extern int proc_kprobes_optimization_handler(struct ctl_table *table, 315 int write, void __user *buffer, 316 size_t *length, loff_t *ppos); 317 #endif 318 extern void wait_for_kprobe_optimizer(void); 319 #else 320 static inline void wait_for_kprobe_optimizer(void) { } 321 #endif /* CONFIG_OPTPROBES */ 322 #ifdef CONFIG_KPROBES_ON_FTRACE 323 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, 324 struct ftrace_ops *ops, struct pt_regs *regs); 325 extern int arch_prepare_kprobe_ftrace(struct kprobe *p); 326 #endif 327 328 int arch_check_ftrace_location(struct kprobe *p); 329 330 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 331 struct kprobe *get_kprobe(void *addr); 332 void kretprobe_hash_lock(struct task_struct *tsk, 333 struct hlist_head **head, unsigned long *flags); 334 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags); 335 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 336 337 /* kprobe_running() will just return the current_kprobe on this CPU */ 338 static inline struct kprobe *kprobe_running(void) 339 { 340 return (__this_cpu_read(current_kprobe)); 341 } 342 343 static inline void reset_current_kprobe(void) 344 { 345 __this_cpu_write(current_kprobe, NULL); 346 } 347 348 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 349 { 350 return this_cpu_ptr(&kprobe_ctlblk); 351 } 352 353 kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset); 354 int register_kprobe(struct kprobe *p); 355 void unregister_kprobe(struct kprobe *p); 356 int register_kprobes(struct kprobe **kps, int num); 357 void unregister_kprobes(struct kprobe **kps, int num); 358 unsigned long arch_deref_entry_point(void *); 359 360 int register_kretprobe(struct kretprobe *rp); 361 void unregister_kretprobe(struct kretprobe *rp); 362 int register_kretprobes(struct kretprobe **rps, int num); 363 void unregister_kretprobes(struct kretprobe **rps, int num); 364 365 void kprobe_flush_task(struct task_struct *tk); 366 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 367 368 int disable_kprobe(struct kprobe *kp); 369 int enable_kprobe(struct kprobe *kp); 370 371 void dump_kprobe(struct kprobe *kp); 372 373 void *alloc_insn_page(void); 374 void free_insn_page(void *page); 375 376 #else /* !CONFIG_KPROBES: */ 377 378 static inline int kprobes_built_in(void) 379 { 380 return 0; 381 } 382 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) 383 { 384 return 0; 385 } 386 static inline struct kprobe *get_kprobe(void *addr) 387 { 388 return NULL; 389 } 390 static inline struct kprobe *kprobe_running(void) 391 { 392 return NULL; 393 } 394 static inline int register_kprobe(struct kprobe *p) 395 { 396 return -ENOSYS; 397 } 398 static inline int register_kprobes(struct kprobe **kps, int num) 399 { 400 return -ENOSYS; 401 } 402 static inline void unregister_kprobe(struct kprobe *p) 403 { 404 } 405 static inline void unregister_kprobes(struct kprobe **kps, int num) 406 { 407 } 408 static inline int register_kretprobe(struct kretprobe *rp) 409 { 410 return -ENOSYS; 411 } 412 static inline int register_kretprobes(struct kretprobe **rps, int num) 413 { 414 return -ENOSYS; 415 } 416 static inline void unregister_kretprobe(struct kretprobe *rp) 417 { 418 } 419 static inline void unregister_kretprobes(struct kretprobe **rps, int num) 420 { 421 } 422 static inline void kprobe_flush_task(struct task_struct *tk) 423 { 424 } 425 static inline int disable_kprobe(struct kprobe *kp) 426 { 427 return -ENOSYS; 428 } 429 static inline int enable_kprobe(struct kprobe *kp) 430 { 431 return -ENOSYS; 432 } 433 434 static inline bool within_kprobe_blacklist(unsigned long addr) 435 { 436 return true; 437 } 438 #endif /* CONFIG_KPROBES */ 439 static inline int disable_kretprobe(struct kretprobe *rp) 440 { 441 return disable_kprobe(&rp->kp); 442 } 443 static inline int enable_kretprobe(struct kretprobe *rp) 444 { 445 return enable_kprobe(&rp->kp); 446 } 447 448 #ifndef CONFIG_KPROBES 449 static inline bool is_kprobe_insn_slot(unsigned long addr) 450 { 451 return false; 452 } 453 #endif 454 #ifndef CONFIG_OPTPROBES 455 static inline bool is_kprobe_optinsn_slot(unsigned long addr) 456 { 457 return false; 458 } 459 #endif 460 461 /* Returns true if kprobes handled the fault */ 462 static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs, 463 unsigned int trap) 464 { 465 if (!kprobes_built_in()) 466 return false; 467 if (user_mode(regs)) 468 return false; 469 /* 470 * To be potentially processing a kprobe fault and to be allowed 471 * to call kprobe_running(), we have to be non-preemptible. 472 */ 473 if (preemptible()) 474 return false; 475 if (!kprobe_running()) 476 return false; 477 return kprobe_fault_handler(regs, trap); 478 } 479 480 #endif /* _LINUX_KPROBES_H */ 481