include/linux/kprobes.h

   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 */