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 42 #ifdef CONFIG_KPROBES 43 #include <asm/kprobes.h> 44 45 /* kprobe_status settings */ 46 #define KPROBE_HIT_ACTIVE 0x00000001 47 #define KPROBE_HIT_SS 0x00000002 48 #define KPROBE_REENTER 0x00000004 49 #define KPROBE_HIT_SSDONE 0x00000008 50 51 /* Attach to insert probes on any functions which should be ignored*/ 52 #define __kprobes __attribute__((__section__(".kprobes.text"))) 53 #else /* CONFIG_KPROBES */ 54 typedef int kprobe_opcode_t; 55 struct arch_specific_insn { 56 int dummy; 57 }; 58 #define __kprobes 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 */ 131 132 /* 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 * Special probe type that uses setjmp-longjmp type tricks to resume 151 * execution at a specified entry with a matching prototype corresponding 152 * to the probed function - a trick to enable arguments to become 153 * accessible seamlessly by probe handling logic. 154 * Note: 155 * Because of the way compilers allocate stack space for local variables 156 * etc upfront, regardless of sub-scopes within a function, this mirroring 157 * principle currently works only for probes placed on function entry points. 158 */ 159 struct jprobe { 160 struct kprobe kp; 161 void *entry; /* probe handling code to jump to */ 162 }; 163 164 /* For backward compatibility with old code using JPROBE_ENTRY() */ 165 #define JPROBE_ENTRY(handler) (handler) 166 167 /* 168 * Function-return probe - 169 * Note: 170 * User needs to provide a handler function, and initialize maxactive. 171 * maxactive - The maximum number of instances of the probed function that 172 * can be active concurrently. 173 * nmissed - tracks the number of times the probed function's return was 174 * ignored, due to maxactive being too low. 175 * 176 */ 177 struct kretprobe { 178 struct kprobe kp; 179 kretprobe_handler_t handler; 180 kretprobe_handler_t entry_handler; 181 int maxactive; 182 int nmissed; 183 size_t data_size; 184 struct hlist_head free_instances; 185 raw_spinlock_t lock; 186 }; 187 188 struct kretprobe_instance { 189 struct hlist_node hlist; 190 struct kretprobe *rp; 191 kprobe_opcode_t *ret_addr; 192 struct task_struct *task; 193 char data[0]; 194 }; 195 196 struct kretprobe_blackpoint { 197 const char *name; 198 void *addr; 199 }; 200 201 struct kprobe_blackpoint { 202 const char *name; 203 unsigned long start_addr; 204 unsigned long range; 205 }; 206 207 #ifdef CONFIG_KPROBES 208 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 209 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 210 211 /* 212 * For #ifdef avoidance: 213 */ 214 static inline int kprobes_built_in(void) 215 { 216 return 1; 217 } 218 219 #ifdef CONFIG_KRETPROBES 220 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 221 struct pt_regs *regs); 222 extern int arch_trampoline_kprobe(struct kprobe *p); 223 #else /* CONFIG_KRETPROBES */ 224 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 225 struct pt_regs *regs) 226 { 227 } 228 static inline int arch_trampoline_kprobe(struct kprobe *p) 229 { 230 return 0; 231 } 232 #endif /* CONFIG_KRETPROBES */ 233 234 extern struct kretprobe_blackpoint kretprobe_blacklist[]; 235 236 static inline void kretprobe_assert(struct kretprobe_instance *ri, 237 unsigned long orig_ret_address, unsigned long trampoline_address) 238 { 239 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 240 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 241 ri->rp, ri->rp->kp.addr); 242 BUG(); 243 } 244 } 245 246 #ifdef CONFIG_KPROBES_SANITY_TEST 247 extern int init_test_probes(void); 248 #else 249 static inline int init_test_probes(void) 250 { 251 return 0; 252 } 253 #endif /* CONFIG_KPROBES_SANITY_TEST */ 254 255 extern int arch_prepare_kprobe(struct kprobe *p); 256 extern void arch_arm_kprobe(struct kprobe *p); 257 extern void arch_disarm_kprobe(struct kprobe *p); 258 extern int arch_init_kprobes(void); 259 extern void show_registers(struct pt_regs *regs); 260 extern kprobe_opcode_t *get_insn_slot(void); 261 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty); 262 extern void kprobes_inc_nmissed_count(struct kprobe *p); 263 264 #ifdef CONFIG_OPTPROBES 265 /* 266 * Internal structure for direct jump optimized probe 267 */ 268 struct optimized_kprobe { 269 struct kprobe kp; 270 struct list_head list; /* list for optimizing queue */ 271 struct arch_optimized_insn optinsn; 272 }; 273 274 /* Architecture dependent functions for direct jump optimization */ 275 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn); 276 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op); 277 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op); 278 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op); 279 extern void arch_optimize_kprobes(struct list_head *oplist); 280 extern void arch_unoptimize_kprobes(struct list_head *oplist, 281 struct list_head *done_list); 282 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op); 283 extern kprobe_opcode_t *get_optinsn_slot(void); 284 extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty); 285 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op, 286 unsigned long addr); 287 288 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs); 289 290 #ifdef CONFIG_SYSCTL 291 extern int sysctl_kprobes_optimization; 292 extern int proc_kprobes_optimization_handler(struct ctl_table *table, 293 int write, void __user *buffer, 294 size_t *length, loff_t *ppos); 295 #endif 296 297 #endif /* CONFIG_OPTPROBES */ 298 299 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 300 struct kprobe *get_kprobe(void *addr); 301 void kretprobe_hash_lock(struct task_struct *tsk, 302 struct hlist_head **head, unsigned long *flags); 303 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags); 304 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 305 306 /* kprobe_running() will just return the current_kprobe on this CPU */ 307 static inline struct kprobe *kprobe_running(void) 308 { 309 return (__this_cpu_read(current_kprobe)); 310 } 311 312 static inline void reset_current_kprobe(void) 313 { 314 __this_cpu_write(current_kprobe, NULL); 315 } 316 317 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 318 { 319 return (&__get_cpu_var(kprobe_ctlblk)); 320 } 321 322 int register_kprobe(struct kprobe *p); 323 void unregister_kprobe(struct kprobe *p); 324 int register_kprobes(struct kprobe **kps, int num); 325 void unregister_kprobes(struct kprobe **kps, int num); 326 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 327 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 328 int register_jprobe(struct jprobe *p); 329 void unregister_jprobe(struct jprobe *p); 330 int register_jprobes(struct jprobe **jps, int num); 331 void unregister_jprobes(struct jprobe **jps, int num); 332 void jprobe_return(void); 333 unsigned long arch_deref_entry_point(void *); 334 335 int register_kretprobe(struct kretprobe *rp); 336 void unregister_kretprobe(struct kretprobe *rp); 337 int register_kretprobes(struct kretprobe **rps, int num); 338 void unregister_kretprobes(struct kretprobe **rps, int num); 339 340 void kprobe_flush_task(struct task_struct *tk); 341 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 342 343 int disable_kprobe(struct kprobe *kp); 344 int enable_kprobe(struct kprobe *kp); 345 346 void dump_kprobe(struct kprobe *kp); 347 348 #else /* !CONFIG_KPROBES: */ 349 350 static inline int kprobes_built_in(void) 351 { 352 return 0; 353 } 354 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) 355 { 356 return 0; 357 } 358 static inline struct kprobe *get_kprobe(void *addr) 359 { 360 return NULL; 361 } 362 static inline struct kprobe *kprobe_running(void) 363 { 364 return NULL; 365 } 366 static inline int register_kprobe(struct kprobe *p) 367 { 368 return -ENOSYS; 369 } 370 static inline int register_kprobes(struct kprobe **kps, int num) 371 { 372 return -ENOSYS; 373 } 374 static inline void unregister_kprobe(struct kprobe *p) 375 { 376 } 377 static inline void unregister_kprobes(struct kprobe **kps, int num) 378 { 379 } 380 static inline int register_jprobe(struct jprobe *p) 381 { 382 return -ENOSYS; 383 } 384 static inline int register_jprobes(struct jprobe **jps, int num) 385 { 386 return -ENOSYS; 387 } 388 static inline void unregister_jprobe(struct jprobe *p) 389 { 390 } 391 static inline void unregister_jprobes(struct jprobe **jps, int num) 392 { 393 } 394 static inline void jprobe_return(void) 395 { 396 } 397 static inline int register_kretprobe(struct kretprobe *rp) 398 { 399 return -ENOSYS; 400 } 401 static inline int register_kretprobes(struct kretprobe **rps, int num) 402 { 403 return -ENOSYS; 404 } 405 static inline void unregister_kretprobe(struct kretprobe *rp) 406 { 407 } 408 static inline void unregister_kretprobes(struct kretprobe **rps, int num) 409 { 410 } 411 static inline void kprobe_flush_task(struct task_struct *tk) 412 { 413 } 414 static inline int disable_kprobe(struct kprobe *kp) 415 { 416 return -ENOSYS; 417 } 418 static inline int enable_kprobe(struct kprobe *kp) 419 { 420 return -ENOSYS; 421 } 422 #endif /* CONFIG_KPROBES */ 423 static inline int disable_kretprobe(struct kretprobe *rp) 424 { 425 return disable_kprobe(&rp->kp); 426 } 427 static inline int enable_kretprobe(struct kretprobe *rp) 428 { 429 return enable_kprobe(&rp->kp); 430 } 431 static inline int disable_jprobe(struct jprobe *jp) 432 { 433 return disable_kprobe(&jp->kp); 434 } 435 static inline int enable_jprobe(struct jprobe *jp) 436 { 437 return enable_kprobe(&jp->kp); 438 } 439 440 #endif /* _LINUX_KPROBES_H */ 441