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/percpu.h> 37 #include <linux/spinlock.h> 38 #include <linux/rcupdate.h> 39 #include <linux/mutex.h> 40 41 #ifdef CONFIG_KPROBES 42 #include <asm/kprobes.h> 43 44 /* kprobe_status settings */ 45 #define KPROBE_HIT_ACTIVE 0x00000001 46 #define KPROBE_HIT_SS 0x00000002 47 #define KPROBE_REENTER 0x00000004 48 #define KPROBE_HIT_SSDONE 0x00000008 49 50 /* Attach to insert probes on any functions which should be ignored*/ 51 #define __kprobes __attribute__((__section__(".kprobes.text"))) 52 #else /* CONFIG_KPROBES */ 53 typedef int kprobe_opcode_t; 54 struct arch_specific_insn { 55 int dummy; 56 }; 57 #define __kprobes 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 */ 125 126 /* 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 * Special probe type that uses setjmp-longjmp type tricks to resume 139 * execution at a specified entry with a matching prototype corresponding 140 * to the probed function - a trick to enable arguments to become 141 * accessible seamlessly by probe handling logic. 142 * Note: 143 * Because of the way compilers allocate stack space for local variables 144 * etc upfront, regardless of sub-scopes within a function, this mirroring 145 * principle currently works only for probes placed on function entry points. 146 */ 147 struct jprobe { 148 struct kprobe kp; 149 void *entry; /* probe handling code to jump to */ 150 }; 151 152 /* For backward compatibility with old code using JPROBE_ENTRY() */ 153 #define JPROBE_ENTRY(handler) (handler) 154 155 /* 156 * Function-return probe - 157 * Note: 158 * User needs to provide a handler function, and initialize maxactive. 159 * maxactive - The maximum number of instances of the probed function that 160 * can be active concurrently. 161 * nmissed - tracks the number of times the probed function's return was 162 * ignored, due to maxactive being too low. 163 * 164 */ 165 struct kretprobe { 166 struct kprobe kp; 167 kretprobe_handler_t handler; 168 kretprobe_handler_t entry_handler; 169 int maxactive; 170 int nmissed; 171 size_t data_size; 172 struct hlist_head free_instances; 173 spinlock_t lock; 174 }; 175 176 struct kretprobe_instance { 177 struct hlist_node hlist; 178 struct kretprobe *rp; 179 kprobe_opcode_t *ret_addr; 180 struct task_struct *task; 181 char data[0]; 182 }; 183 184 struct kretprobe_blackpoint { 185 const char *name; 186 void *addr; 187 }; 188 189 struct kprobe_blackpoint { 190 const char *name; 191 unsigned long start_addr; 192 unsigned long range; 193 }; 194 195 #ifdef CONFIG_KPROBES 196 DECLARE_PER_CPU(struct kprobe *, current_kprobe); 197 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); 198 199 /* 200 * For #ifdef avoidance: 201 */ 202 static inline int kprobes_built_in(void) 203 { 204 return 1; 205 } 206 207 #ifdef CONFIG_KRETPROBES 208 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, 209 struct pt_regs *regs); 210 extern int arch_trampoline_kprobe(struct kprobe *p); 211 #else /* CONFIG_KRETPROBES */ 212 static inline void arch_prepare_kretprobe(struct kretprobe *rp, 213 struct pt_regs *regs) 214 { 215 } 216 static inline int arch_trampoline_kprobe(struct kprobe *p) 217 { 218 return 0; 219 } 220 #endif /* CONFIG_KRETPROBES */ 221 222 extern struct kretprobe_blackpoint kretprobe_blacklist[]; 223 224 static inline void kretprobe_assert(struct kretprobe_instance *ri, 225 unsigned long orig_ret_address, unsigned long trampoline_address) 226 { 227 if (!orig_ret_address || (orig_ret_address == trampoline_address)) { 228 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", 229 ri->rp, ri->rp->kp.addr); 230 BUG(); 231 } 232 } 233 234 #ifdef CONFIG_KPROBES_SANITY_TEST 235 extern int init_test_probes(void); 236 #else 237 static inline int init_test_probes(void) 238 { 239 return 0; 240 } 241 #endif /* CONFIG_KPROBES_SANITY_TEST */ 242 243 extern int arch_prepare_kprobe(struct kprobe *p); 244 extern void arch_arm_kprobe(struct kprobe *p); 245 extern void arch_disarm_kprobe(struct kprobe *p); 246 extern int arch_init_kprobes(void); 247 extern void show_registers(struct pt_regs *regs); 248 extern kprobe_opcode_t *get_insn_slot(void); 249 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty); 250 extern void kprobes_inc_nmissed_count(struct kprobe *p); 251 252 /* Get the kprobe at this addr (if any) - called with preemption disabled */ 253 struct kprobe *get_kprobe(void *addr); 254 void kretprobe_hash_lock(struct task_struct *tsk, 255 struct hlist_head **head, unsigned long *flags); 256 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags); 257 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); 258 259 /* kprobe_running() will just return the current_kprobe on this CPU */ 260 static inline struct kprobe *kprobe_running(void) 261 { 262 return (__get_cpu_var(current_kprobe)); 263 } 264 265 static inline void reset_current_kprobe(void) 266 { 267 __get_cpu_var(current_kprobe) = NULL; 268 } 269 270 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) 271 { 272 return (&__get_cpu_var(kprobe_ctlblk)); 273 } 274 275 int register_kprobe(struct kprobe *p); 276 void unregister_kprobe(struct kprobe *p); 277 int register_kprobes(struct kprobe **kps, int num); 278 void unregister_kprobes(struct kprobe **kps, int num); 279 int setjmp_pre_handler(struct kprobe *, struct pt_regs *); 280 int longjmp_break_handler(struct kprobe *, struct pt_regs *); 281 int register_jprobe(struct jprobe *p); 282 void unregister_jprobe(struct jprobe *p); 283 int register_jprobes(struct jprobe **jps, int num); 284 void unregister_jprobes(struct jprobe **jps, int num); 285 void jprobe_return(void); 286 unsigned long arch_deref_entry_point(void *); 287 288 int register_kretprobe(struct kretprobe *rp); 289 void unregister_kretprobe(struct kretprobe *rp); 290 int register_kretprobes(struct kretprobe **rps, int num); 291 void unregister_kretprobes(struct kretprobe **rps, int num); 292 293 void kprobe_flush_task(struct task_struct *tk); 294 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); 295 296 int disable_kprobe(struct kprobe *kp); 297 int enable_kprobe(struct kprobe *kp); 298 299 void dump_kprobe(struct kprobe *kp); 300 301 #else /* !CONFIG_KPROBES: */ 302 303 static inline int kprobes_built_in(void) 304 { 305 return 0; 306 } 307 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) 308 { 309 return 0; 310 } 311 static inline struct kprobe *get_kprobe(void *addr) 312 { 313 return NULL; 314 } 315 static inline struct kprobe *kprobe_running(void) 316 { 317 return NULL; 318 } 319 static inline int register_kprobe(struct kprobe *p) 320 { 321 return -ENOSYS; 322 } 323 static inline int register_kprobes(struct kprobe **kps, int num) 324 { 325 return -ENOSYS; 326 } 327 static inline void unregister_kprobe(struct kprobe *p) 328 { 329 } 330 static inline void unregister_kprobes(struct kprobe **kps, int num) 331 { 332 } 333 static inline int register_jprobe(struct jprobe *p) 334 { 335 return -ENOSYS; 336 } 337 static inline int register_jprobes(struct jprobe **jps, int num) 338 { 339 return -ENOSYS; 340 } 341 static inline void unregister_jprobe(struct jprobe *p) 342 { 343 } 344 static inline void unregister_jprobes(struct jprobe **jps, int num) 345 { 346 } 347 static inline void jprobe_return(void) 348 { 349 } 350 static inline int register_kretprobe(struct kretprobe *rp) 351 { 352 return -ENOSYS; 353 } 354 static inline int register_kretprobes(struct kretprobe **rps, int num) 355 { 356 return -ENOSYS; 357 } 358 static inline void unregister_kretprobe(struct kretprobe *rp) 359 { 360 } 361 static inline void unregister_kretprobes(struct kretprobe **rps, int num) 362 { 363 } 364 static inline void kprobe_flush_task(struct task_struct *tk) 365 { 366 } 367 static inline int disable_kprobe(struct kprobe *kp) 368 { 369 return -ENOSYS; 370 } 371 static inline int enable_kprobe(struct kprobe *kp) 372 { 373 return -ENOSYS; 374 } 375 #endif /* CONFIG_KPROBES */ 376 static inline int disable_kretprobe(struct kretprobe *rp) 377 { 378 return disable_kprobe(&rp->kp); 379 } 380 static inline int enable_kretprobe(struct kretprobe *rp) 381 { 382 return enable_kprobe(&rp->kp); 383 } 384 static inline int disable_jprobe(struct jprobe *jp) 385 { 386 return disable_kprobe(&jp->kp); 387 } 388 static inline int enable_jprobe(struct jprobe *jp) 389 { 390 return enable_kprobe(&jp->kp); 391 } 392 393 #endif /* _LINUX_KPROBES_H */ 394