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 #include <linux/ftrace.h>
  42
  43 #ifdef CONFIG_KPROBES
  44 #include <asm/kprobes.h>
  45
  46 /* kprobe_status settings */
  47 #define KPROBE_HIT_ACTIVE       0x00000001
  48 #define KPROBE_HIT_SS           0x00000002
  49 #define KPROBE_REENTER          0x00000004
  50 #define KPROBE_HIT_SSDONE       0x00000008
  51
  52 /*
  53  * If function tracer is enabled and the arch supports full
  54  * passing of pt_regs to function tracing, then kprobes can
  55  * optimize on top of function tracing.
  56  */
  57 #if defined(CONFIG_FUNCTION_TRACER) && defined(ARCH_SUPPORTS_FTRACE_SAVE_REGS) \
  58         && defined(ARCH_SUPPORTS_KPROBES_ON_FTRACE)
  59 # define KPROBES_CAN_USE_FTRACE
  60 #endif
  61
  62 /* Attach to insert probes on any functions which should be ignored*/
  63 #define __kprobes       __attribute__((__section__(".kprobes.text")))
  64
  65 #else /* CONFIG_KPROBES */
  66 typedef int kprobe_opcode_t;
  67 struct arch_specific_insn {
  68         int dummy;
  69 };
  70 #define __kprobes
  71
  72 #endif /* CONFIG_KPROBES */
  73
  74 struct kprobe;
  75 struct pt_regs;
  76 struct kretprobe;
  77 struct kretprobe_instance;
  78 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  79 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  80 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  81                                        unsigned long flags);
  82 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  83                                        int trapnr);
  84 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
  85                                     struct pt_regs *);
  86
  87 struct kprobe {
  88         struct hlist_node hlist;
  89
  90         /* list of kprobes for multi-handler support */
  91         struct list_head list;
  92
  93         /*count the number of times this probe was temporarily disarmed */
  94         unsigned long nmissed;
  95
  96         /* location of the probe point */
  97         kprobe_opcode_t *addr;
  98
  99         /* Allow user to indicate symbol name of the probe point */
 100         const char *symbol_name;
 101
 102         /* Offset into the symbol */
 103         unsigned int offset;
 104
 105         /* Called before addr is executed. */
 106         kprobe_pre_handler_t pre_handler;
 107
 108         /* Called after addr is executed, unless... */
 109         kprobe_post_handler_t post_handler;
 110
 111         /*
 112          * ... called if executing addr causes a fault (eg. page fault).
 113          * Return 1 if it handled fault, otherwise kernel will see it.
 114          */
 115         kprobe_fault_handler_t fault_handler;
 116
 117         /*
 118          * ... called if breakpoint trap occurs in probe handler.
 119          * Return 1 if it handled break, otherwise kernel will see it.
 120          */
 121         kprobe_break_handler_t break_handler;
 122
 123         /* Saved opcode (which has been replaced with breakpoint) */
 124         kprobe_opcode_t opcode;
 125
 126         /* copy of the original instruction */
 127         struct arch_specific_insn ainsn;
 128
 129         /*
 130          * Indicates various status flags.
 131          * Protected by kprobe_mutex after this kprobe is registered.
 132          */
 133         u32 flags;
 134 };
 135
 136 /* Kprobe status flags */
 137 #define KPROBE_FLAG_GONE        1 /* breakpoint has already gone */
 138 #define KPROBE_FLAG_DISABLED    2 /* probe is temporarily disabled */
 139 #define KPROBE_FLAG_OPTIMIZED   4 /*
 140                                    * probe is really optimized.
 141                                    * NOTE:
 142                                    * this flag is only for optimized_kprobe.
 143                                    */
 144 #define KPROBE_FLAG_FTRACE      8 /* probe is using ftrace */
 145
 146 /* Has this kprobe gone ? */
 147 static inline int kprobe_gone(struct kprobe *p)
 148 {
 149         return p->flags & KPROBE_FLAG_GONE;
 150 }
 151
 152 /* Is this kprobe disabled ? */
 153 static inline int kprobe_disabled(struct kprobe *p)
 154 {
 155         return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
 156 }
 157
 158 /* Is this kprobe really running optimized path ? */
 159 static inline int kprobe_optimized(struct kprobe *p)
 160 {
 161         return p->flags & KPROBE_FLAG_OPTIMIZED;
 162 }
 163
 164 /* Is this kprobe uses ftrace ? */
 165 static inline int kprobe_ftrace(struct kprobe *p)
 166 {
 167         return p->flags & KPROBE_FLAG_FTRACE;
 168 }
 169
 170 /*
 171  * Special probe type that uses setjmp-longjmp type tricks to resume
 172  * execution at a specified entry with a matching prototype corresponding
 173  * to the probed function - a trick to enable arguments to become
 174  * accessible seamlessly by probe handling logic.
 175  * Note:
 176  * Because of the way compilers allocate stack space for local variables
 177  * etc upfront, regardless of sub-scopes within a function, this mirroring
 178  * principle currently works only for probes placed on function entry points.
 179  */
 180 struct jprobe {
 181         struct kprobe kp;
 182         void *entry;    /* probe handling code to jump to */
 183 };
 184
 185 /* For backward compatibility with old code using JPROBE_ENTRY() */
 186 #define JPROBE_ENTRY(handler)   (handler)
 187
 188 /*
 189  * Function-return probe -
 190  * Note:
 191  * User needs to provide a handler function, and initialize maxactive.
 192  * maxactive - The maximum number of instances of the probed function that
 193  * can be active concurrently.
 194  * nmissed - tracks the number of times the probed function's return was
 195  * ignored, due to maxactive being too low.
 196  *
 197  */
 198 struct kretprobe {
 199         struct kprobe kp;
 200         kretprobe_handler_t handler;
 201         kretprobe_handler_t entry_handler;
 202         int maxactive;
 203         int nmissed;
 204         size_t data_size;
 205         struct hlist_head free_instances;
 206         raw_spinlock_t lock;
 207 };
 208
 209 struct kretprobe_instance {
 210         struct hlist_node hlist;
 211         struct kretprobe *rp;
 212         kprobe_opcode_t *ret_addr;
 213         struct task_struct *task;
 214         char data[0];
 215 };
 216
 217 struct kretprobe_blackpoint {
 218         const char *name;
 219         void *addr;
 220 };
 221
 222 struct kprobe_blackpoint {
 223         const char *name;
 224         unsigned long start_addr;
 225         unsigned long range;
 226 };
 227
 228 #ifdef CONFIG_KPROBES
 229 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 230 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 231
 232 /*
 233  * For #ifdef avoidance:
 234  */
 235 static inline int kprobes_built_in(void)
 236 {
 237         return 1;
 238 }
 239
 240 #ifdef CONFIG_KRETPROBES
 241 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 242                                    struct pt_regs *regs);
 243 extern int arch_trampoline_kprobe(struct kprobe *p);
 244 #else /* CONFIG_KRETPROBES */
 245 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 246                                         struct pt_regs *regs)
 247 {
 248 }
 249 static inline int arch_trampoline_kprobe(struct kprobe *p)
 250 {
 251         return 0;
 252 }
 253 #endif /* CONFIG_KRETPROBES */
 254
 255 extern struct kretprobe_blackpoint kretprobe_blacklist[];
 256
 257 static inline void kretprobe_assert(struct kretprobe_instance *ri,
 258         unsigned long orig_ret_address, unsigned long trampoline_address)
 259 {
 260         if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
 261                 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
 262                                 ri->rp, ri->rp->kp.addr);
 263                 BUG();
 264         }
 265 }
 266
 267 #ifdef CONFIG_KPROBES_SANITY_TEST
 268 extern int init_test_probes(void);
 269 #else
 270 static inline int init_test_probes(void)
 271 {
 272         return 0;
 273 }
 274 #endif /* CONFIG_KPROBES_SANITY_TEST */
 275
 276 extern int arch_prepare_kprobe(struct kprobe *p);
 277 extern void arch_arm_kprobe(struct kprobe *p);
 278 extern void arch_disarm_kprobe(struct kprobe *p);
 279 extern int arch_init_kprobes(void);
 280 extern void show_registers(struct pt_regs *regs);
 281 extern kprobe_opcode_t *get_insn_slot(void);
 282 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
 283 extern void kprobes_inc_nmissed_count(struct kprobe *p);
 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 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
 300 extern void arch_optimize_kprobes(struct list_head *oplist);
 301 extern void arch_unoptimize_kprobes(struct list_head *oplist,
 302                                     struct list_head *done_list);
 303 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
 304 extern kprobe_opcode_t *get_optinsn_slot(void);
 305 extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
 306 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
 307                                         unsigned long addr);
 308
 309 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
 310
 311 #ifdef CONFIG_SYSCTL
 312 extern int sysctl_kprobes_optimization;
 313 extern int proc_kprobes_optimization_handler(struct ctl_table *table,
 314                                              int write, void __user *buffer,
 315                                              size_t *length, loff_t *ppos);
 316 #endif
 317
 318 #endif /* CONFIG_OPTPROBES */
 319 #ifdef KPROBES_CAN_USE_FTRACE
 320 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 321                                   struct ftrace_ops *ops, struct pt_regs *regs);
 322 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
 323 #endif
 324
 325
 326 /* Get the kprobe at this addr (if any) - called with preemption disabled */
 327 struct kprobe *get_kprobe(void *addr);
 328 void kretprobe_hash_lock(struct task_struct *tsk,
 329                          struct hlist_head **head, unsigned long *flags);
 330 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
 331 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 332
 333 /* kprobe_running() will just return the current_kprobe on this CPU */
 334 static inline struct kprobe *kprobe_running(void)
 335 {
 336         return (__this_cpu_read(current_kprobe));
 337 }
 338
 339 static inline void reset_current_kprobe(void)
 340 {
 341         __this_cpu_write(current_kprobe, NULL);
 342 }
 343
 344 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 345 {
 346         return (&__get_cpu_var(kprobe_ctlblk));
 347 }
 348
 349 int register_kprobe(struct kprobe *p);
 350 void unregister_kprobe(struct kprobe *p);
 351 int register_kprobes(struct kprobe **kps, int num);
 352 void unregister_kprobes(struct kprobe **kps, int num);
 353 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 354 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 355 int register_jprobe(struct jprobe *p);
 356 void unregister_jprobe(struct jprobe *p);
 357 int register_jprobes(struct jprobe **jps, int num);
 358 void unregister_jprobes(struct jprobe **jps, int num);
 359 void jprobe_return(void);
 360 unsigned long arch_deref_entry_point(void *);
 361
 362 int register_kretprobe(struct kretprobe *rp);
 363 void unregister_kretprobe(struct kretprobe *rp);
 364 int register_kretprobes(struct kretprobe **rps, int num);
 365 void unregister_kretprobes(struct kretprobe **rps, int num);
 366
 367 void kprobe_flush_task(struct task_struct *tk);
 368 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 369
 370 int disable_kprobe(struct kprobe *kp);
 371 int enable_kprobe(struct kprobe *kp);
 372
 373 void dump_kprobe(struct kprobe *kp);
 374
 375 #else /* !CONFIG_KPROBES: */
 376
 377 static inline int kprobes_built_in(void)
 378 {
 379         return 0;
 380 }
 381 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 382 {
 383         return 0;
 384 }
 385 static inline struct kprobe *get_kprobe(void *addr)
 386 {
 387         return NULL;
 388 }
 389 static inline struct kprobe *kprobe_running(void)
 390 {
 391         return NULL;
 392 }
 393 static inline int register_kprobe(struct kprobe *p)
 394 {
 395         return -ENOSYS;
 396 }
 397 static inline int register_kprobes(struct kprobe **kps, int num)
 398 {
 399         return -ENOSYS;
 400 }
 401 static inline void unregister_kprobe(struct kprobe *p)
 402 {
 403 }
 404 static inline void unregister_kprobes(struct kprobe **kps, int num)
 405 {
 406 }
 407 static inline int register_jprobe(struct jprobe *p)
 408 {
 409         return -ENOSYS;
 410 }
 411 static inline int register_jprobes(struct jprobe **jps, int num)
 412 {
 413         return -ENOSYS;
 414 }
 415 static inline void unregister_jprobe(struct jprobe *p)
 416 {
 417 }
 418 static inline void unregister_jprobes(struct jprobe **jps, int num)
 419 {
 420 }
 421 static inline void jprobe_return(void)
 422 {
 423 }
 424 static inline int register_kretprobe(struct kretprobe *rp)
 425 {
 426         return -ENOSYS;
 427 }
 428 static inline int register_kretprobes(struct kretprobe **rps, int num)
 429 {
 430         return -ENOSYS;
 431 }
 432 static inline void unregister_kretprobe(struct kretprobe *rp)
 433 {
 434 }
 435 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 436 {
 437 }
 438 static inline void kprobe_flush_task(struct task_struct *tk)
 439 {
 440 }
 441 static inline int disable_kprobe(struct kprobe *kp)
 442 {
 443         return -ENOSYS;
 444 }
 445 static inline int enable_kprobe(struct kprobe *kp)
 446 {
 447         return -ENOSYS;
 448 }
 449 #endif /* CONFIG_KPROBES */
 450 static inline int disable_kretprobe(struct kretprobe *rp)
 451 {
 452         return disable_kprobe(&rp->kp);
 453 }
 454 static inline int enable_kretprobe(struct kretprobe *rp)
 455 {
 456         return enable_kprobe(&rp->kp);
 457 }
 458 static inline int disable_jprobe(struct jprobe *jp)
 459 {
 460         return disable_kprobe(&jp->kp);
 461 }
 462 static inline int enable_jprobe(struct jprobe *jp)
 463 {
 464         return enable_kprobe(&jp->kp);
 465 }
 466
 467 #endif /* _LINUX_KPROBES_H */