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/compiler.h>     /* for __kprobes */
  33 #include <linux/linkage.h>
  34 #include <linux/list.h>
  35 #include <linux/notifier.h>
  36 #include <linux/smp.h>
  37 #include <linux/bug.h>
  38 #include <linux/percpu.h>
  39 #include <linux/spinlock.h>
  40 #include <linux/rcupdate.h>
  41 #include <linux/mutex.h>
  42 #include <linux/ftrace.h>
  43
  44 #ifdef CONFIG_KPROBES
  45 #include <asm/kprobes.h>
  46
  47 /* kprobe_status settings */
  48 #define KPROBE_HIT_ACTIVE       0x00000001
  49 #define KPROBE_HIT_SS           0x00000002
  50 #define KPROBE_REENTER          0x00000004
  51 #define KPROBE_HIT_SSDONE       0x00000008
  52
  53 #else /* CONFIG_KPROBES */
  54 typedef int kprobe_opcode_t;
  55 struct arch_specific_insn {
  56         int dummy;
  57 };
  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 #define KPROBE_FLAG_OPTIMIZED   4 /*
 126                                    * probe is really optimized.
 127                                    * NOTE:
 128                                    * this flag is only for optimized_kprobe.
 129                                    */
 130 #define KPROBE_FLAG_FTRACE      8 /* probe is using ftrace */
 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 /* Is this kprobe uses ftrace ? */
 151 static inline int kprobe_ftrace(struct kprobe *p)
 152 {
 153         return p->flags & KPROBE_FLAG_FTRACE;
 154 }
 155
 156 /*
 157  * Special probe type that uses setjmp-longjmp type tricks to resume
 158  * execution at a specified entry with a matching prototype corresponding
 159  * to the probed function - a trick to enable arguments to become
 160  * accessible seamlessly by probe handling logic.
 161  * Note:
 162  * Because of the way compilers allocate stack space for local variables
 163  * etc upfront, regardless of sub-scopes within a function, this mirroring
 164  * principle currently works only for probes placed on function entry points.
 165  */
 166 struct jprobe {
 167         struct kprobe kp;
 168         void *entry;    /* probe handling code to jump to */
 169 };
 170
 171 /* For backward compatibility with old code using JPROBE_ENTRY() */
 172 #define JPROBE_ENTRY(handler)   (handler)
 173
 174 /*
 175  * Function-return probe -
 176  * Note:
 177  * User needs to provide a handler function, and initialize maxactive.
 178  * maxactive - The maximum number of instances of the probed function that
 179  * can be active concurrently.
 180  * nmissed - tracks the number of times the probed function's return was
 181  * ignored, due to maxactive being too low.
 182  *
 183  */
 184 struct kretprobe {
 185         struct kprobe kp;
 186         kretprobe_handler_t handler;
 187         kretprobe_handler_t entry_handler;
 188         int maxactive;
 189         int nmissed;
 190         size_t data_size;
 191         struct hlist_head free_instances;
 192         raw_spinlock_t lock;
 193 };
 194
 195 struct kretprobe_instance {
 196         struct hlist_node hlist;
 197         struct kretprobe *rp;
 198         kprobe_opcode_t *ret_addr;
 199         struct task_struct *task;
 200         char data[0];
 201 };
 202
 203 struct kretprobe_blackpoint {
 204         const char *name;
 205         void *addr;
 206 };
 207
 208 struct kprobe_blackpoint {
 209         const char *name;
 210         unsigned long start_addr;
 211         unsigned long range;
 212 };
 213
 214 #ifdef CONFIG_KPROBES
 215 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 216 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 217
 218 /*
 219  * For #ifdef avoidance:
 220  */
 221 static inline int kprobes_built_in(void)
 222 {
 223         return 1;
 224 }
 225
 226 #ifdef CONFIG_KRETPROBES
 227 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 228                                    struct pt_regs *regs);
 229 extern int arch_trampoline_kprobe(struct kprobe *p);
 230 #else /* CONFIG_KRETPROBES */
 231 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 232                                         struct pt_regs *regs)
 233 {
 234 }
 235 static inline int arch_trampoline_kprobe(struct kprobe *p)
 236 {
 237         return 0;
 238 }
 239 #endif /* CONFIG_KRETPROBES */
 240
 241 extern struct kretprobe_blackpoint kretprobe_blacklist[];
 242
 243 static inline void kretprobe_assert(struct kretprobe_instance *ri,
 244         unsigned long orig_ret_address, unsigned long trampoline_address)
 245 {
 246         if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
 247                 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
 248                                 ri->rp, ri->rp->kp.addr);
 249                 BUG();
 250         }
 251 }
 252
 253 #ifdef CONFIG_KPROBES_SANITY_TEST
 254 extern int init_test_probes(void);
 255 #else
 256 static inline int init_test_probes(void)
 257 {
 258         return 0;
 259 }
 260 #endif /* CONFIG_KPROBES_SANITY_TEST */
 261
 262 extern int arch_prepare_kprobe(struct kprobe *p);
 263 extern void arch_arm_kprobe(struct kprobe *p);
 264 extern void arch_disarm_kprobe(struct kprobe *p);
 265 extern int arch_init_kprobes(void);
 266 extern void show_registers(struct pt_regs *regs);
 267 extern kprobe_opcode_t *get_insn_slot(void);
 268 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
 269 extern void kprobes_inc_nmissed_count(struct kprobe *p);
 270
 271 #ifdef CONFIG_OPTPROBES
 272 /*
 273  * Internal structure for direct jump optimized probe
 274  */
 275 struct optimized_kprobe {
 276         struct kprobe kp;
 277         struct list_head list;  /* list for optimizing queue */
 278         struct arch_optimized_insn optinsn;
 279 };
 280
 281 /* Architecture dependent functions for direct jump optimization */
 282 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
 283 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
 284 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
 285 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
 286 extern void arch_optimize_kprobes(struct list_head *oplist);
 287 extern void arch_unoptimize_kprobes(struct list_head *oplist,
 288                                     struct list_head *done_list);
 289 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
 290 extern kprobe_opcode_t *get_optinsn_slot(void);
 291 extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
 292 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
 293                                         unsigned long addr);
 294
 295 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
 296
 297 #ifdef CONFIG_SYSCTL
 298 extern int sysctl_kprobes_optimization;
 299 extern int proc_kprobes_optimization_handler(struct ctl_table *table,
 300                                              int write, void __user *buffer,
 301                                              size_t *length, loff_t *ppos);
 302 #endif
 303
 304 #endif /* CONFIG_OPTPROBES */
 305 #ifdef CONFIG_KPROBES_ON_FTRACE
 306 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 307                                   struct ftrace_ops *ops, struct pt_regs *regs);
 308 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
 309 #endif
 310
 311
 312 /* Get the kprobe at this addr (if any) - called with preemption disabled */
 313 struct kprobe *get_kprobe(void *addr);
 314 void kretprobe_hash_lock(struct task_struct *tsk,
 315                          struct hlist_head **head, unsigned long *flags);
 316 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
 317 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 318
 319 /* kprobe_running() will just return the current_kprobe on this CPU */
 320 static inline struct kprobe *kprobe_running(void)
 321 {
 322         return (__this_cpu_read(current_kprobe));
 323 }
 324
 325 static inline void reset_current_kprobe(void)
 326 {
 327         __this_cpu_write(current_kprobe, NULL);
 328 }
 329
 330 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 331 {
 332         return (&__get_cpu_var(kprobe_ctlblk));
 333 }
 334
 335 int register_kprobe(struct kprobe *p);
 336 void unregister_kprobe(struct kprobe *p);
 337 int register_kprobes(struct kprobe **kps, int num);
 338 void unregister_kprobes(struct kprobe **kps, int num);
 339 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 340 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 341 int register_jprobe(struct jprobe *p);
 342 void unregister_jprobe(struct jprobe *p);
 343 int register_jprobes(struct jprobe **jps, int num);
 344 void unregister_jprobes(struct jprobe **jps, int num);
 345 void jprobe_return(void);
 346 unsigned long arch_deref_entry_point(void *);
 347
 348 int register_kretprobe(struct kretprobe *rp);
 349 void unregister_kretprobe(struct kretprobe *rp);
 350 int register_kretprobes(struct kretprobe **rps, int num);
 351 void unregister_kretprobes(struct kretprobe **rps, int num);
 352
 353 void kprobe_flush_task(struct task_struct *tk);
 354 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 355
 356 int disable_kprobe(struct kprobe *kp);
 357 int enable_kprobe(struct kprobe *kp);
 358
 359 void dump_kprobe(struct kprobe *kp);
 360
 361 #else /* !CONFIG_KPROBES: */
 362
 363 static inline int kprobes_built_in(void)
 364 {
 365         return 0;
 366 }
 367 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 368 {
 369         return 0;
 370 }
 371 static inline struct kprobe *get_kprobe(void *addr)
 372 {
 373         return NULL;
 374 }
 375 static inline struct kprobe *kprobe_running(void)
 376 {
 377         return NULL;
 378 }
 379 static inline int register_kprobe(struct kprobe *p)
 380 {
 381         return -ENOSYS;
 382 }
 383 static inline int register_kprobes(struct kprobe **kps, int num)
 384 {
 385         return -ENOSYS;
 386 }
 387 static inline void unregister_kprobe(struct kprobe *p)
 388 {
 389 }
 390 static inline void unregister_kprobes(struct kprobe **kps, int num)
 391 {
 392 }
 393 static inline int register_jprobe(struct jprobe *p)
 394 {
 395         return -ENOSYS;
 396 }
 397 static inline int register_jprobes(struct jprobe **jps, int num)
 398 {
 399         return -ENOSYS;
 400 }
 401 static inline void unregister_jprobe(struct jprobe *p)
 402 {
 403 }
 404 static inline void unregister_jprobes(struct jprobe **jps, int num)
 405 {
 406 }
 407 static inline void jprobe_return(void)
 408 {
 409 }
 410 static inline int register_kretprobe(struct kretprobe *rp)
 411 {
 412         return -ENOSYS;
 413 }
 414 static inline int register_kretprobes(struct kretprobe **rps, int num)
 415 {
 416         return -ENOSYS;
 417 }
 418 static inline void unregister_kretprobe(struct kretprobe *rp)
 419 {
 420 }
 421 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 422 {
 423 }
 424 static inline void kprobe_flush_task(struct task_struct *tk)
 425 {
 426 }
 427 static inline int disable_kprobe(struct kprobe *kp)
 428 {
 429         return -ENOSYS;
 430 }
 431 static inline int enable_kprobe(struct kprobe *kp)
 432 {
 433         return -ENOSYS;
 434 }
 435 #endif /* CONFIG_KPROBES */
 436 static inline int disable_kretprobe(struct kretprobe *rp)
 437 {
 438         return disable_kprobe(&rp->kp);
 439 }
 440 static inline int enable_kretprobe(struct kretprobe *rp)
 441 {
 442         return enable_kprobe(&rp->kp);
 443 }
 444 static inline int disable_jprobe(struct jprobe *jp)
 445 {
 446         return disable_kprobe(&jp->kp);
 447 }
 448 static inline int enable_jprobe(struct jprobe *jp)
 449 {
 450         return enable_kprobe(&jp->kp);
 451 }
 452
 453 #endif /* _LINUX_KPROBES_H */