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/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 #define KPROBE_FLAG_OPTIMIZED   4 /*
 126                                    * probe is really optimized.
 127                                    * NOTE:
 128                                    * this flag is only for optimized_kprobe.
 129                                    */
 130
 131 /* Has this kprobe gone ? */
 132 static inline int kprobe_gone(struct kprobe *p)
 133 {
 134         return p->flags & KPROBE_FLAG_GONE;
 135 }
 136
 137 /* Is this kprobe disabled ? */
 138 static inline int kprobe_disabled(struct kprobe *p)
 139 {
 140         return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
 141 }
 142
 143 /* Is this kprobe really running optimized path ? */
 144 static inline int kprobe_optimized(struct kprobe *p)
 145 {
 146         return p->flags & KPROBE_FLAG_OPTIMIZED;
 147 }
 148 /*
 149  * Special probe type that uses setjmp-longjmp type tricks to resume
 150  * execution at a specified entry with a matching prototype corresponding
 151  * to the probed function - a trick to enable arguments to become
 152  * accessible seamlessly by probe handling logic.
 153  * Note:
 154  * Because of the way compilers allocate stack space for local variables
 155  * etc upfront, regardless of sub-scopes within a function, this mirroring
 156  * principle currently works only for probes placed on function entry points.
 157  */
 158 struct jprobe {
 159         struct kprobe kp;
 160         void *entry;    /* probe handling code to jump to */
 161 };
 162
 163 /* For backward compatibility with old code using JPROBE_ENTRY() */
 164 #define JPROBE_ENTRY(handler)   (handler)
 165
 166 /*
 167  * Function-return probe -
 168  * Note:
 169  * User needs to provide a handler function, and initialize maxactive.
 170  * maxactive - The maximum number of instances of the probed function that
 171  * can be active concurrently.
 172  * nmissed - tracks the number of times the probed function's return was
 173  * ignored, due to maxactive being too low.
 174  *
 175  */
 176 struct kretprobe {
 177         struct kprobe kp;
 178         kretprobe_handler_t handler;
 179         kretprobe_handler_t entry_handler;
 180         int maxactive;
 181         int nmissed;
 182         size_t data_size;
 183         struct hlist_head free_instances;
 184         raw_spinlock_t lock;
 185 };
 186
 187 struct kretprobe_instance {
 188         struct hlist_node hlist;
 189         struct kretprobe *rp;
 190         kprobe_opcode_t *ret_addr;
 191         struct task_struct *task;
 192         char data[0];
 193 };
 194
 195 struct kretprobe_blackpoint {
 196         const char *name;
 197         void *addr;
 198 };
 199
 200 struct kprobe_blackpoint {
 201         const char *name;
 202         unsigned long start_addr;
 203         unsigned long range;
 204 };
 205
 206 #ifdef CONFIG_KPROBES
 207 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 208 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 209
 210 /*
 211  * For #ifdef avoidance:
 212  */
 213 static inline int kprobes_built_in(void)
 214 {
 215         return 1;
 216 }
 217
 218 #ifdef CONFIG_KRETPROBES
 219 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 220                                    struct pt_regs *regs);
 221 extern int arch_trampoline_kprobe(struct kprobe *p);
 222 #else /* CONFIG_KRETPROBES */
 223 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 224                                         struct pt_regs *regs)
 225 {
 226 }
 227 static inline int arch_trampoline_kprobe(struct kprobe *p)
 228 {
 229         return 0;
 230 }
 231 #endif /* CONFIG_KRETPROBES */
 232
 233 extern struct kretprobe_blackpoint kretprobe_blacklist[];
 234
 235 static inline void kretprobe_assert(struct kretprobe_instance *ri,
 236         unsigned long orig_ret_address, unsigned long trampoline_address)
 237 {
 238         if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
 239                 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
 240                                 ri->rp, ri->rp->kp.addr);
 241                 BUG();
 242         }
 243 }
 244
 245 #ifdef CONFIG_KPROBES_SANITY_TEST
 246 extern int init_test_probes(void);
 247 #else
 248 static inline int init_test_probes(void)
 249 {
 250         return 0;
 251 }
 252 #endif /* CONFIG_KPROBES_SANITY_TEST */
 253
 254 extern int arch_prepare_kprobe(struct kprobe *p);
 255 extern void arch_arm_kprobe(struct kprobe *p);
 256 extern void arch_disarm_kprobe(struct kprobe *p);
 257 extern int arch_init_kprobes(void);
 258 extern void show_registers(struct pt_regs *regs);
 259 extern kprobe_opcode_t *get_insn_slot(void);
 260 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
 261 extern void kprobes_inc_nmissed_count(struct kprobe *p);
 262
 263 #ifdef CONFIG_OPTPROBES
 264 /*
 265  * Internal structure for direct jump optimized probe
 266  */
 267 struct optimized_kprobe {
 268         struct kprobe kp;
 269         struct list_head list;  /* list for optimizing queue */
 270         struct arch_optimized_insn optinsn;
 271 };
 272
 273 /* Architecture dependent functions for direct jump optimization */
 274 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
 275 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
 276 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
 277 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
 278 extern void arch_optimize_kprobes(struct list_head *oplist);
 279 extern void arch_unoptimize_kprobes(struct list_head *oplist,
 280                                     struct list_head *done_list);
 281 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
 282 extern kprobe_opcode_t *get_optinsn_slot(void);
 283 extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
 284 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
 285                                         unsigned long addr);
 286
 287 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
 288
 289 #ifdef CONFIG_SYSCTL
 290 extern int sysctl_kprobes_optimization;
 291 extern int proc_kprobes_optimization_handler(struct ctl_table *table,
 292                                              int write, void __user *buffer,
 293                                              size_t *length, loff_t *ppos);
 294 #endif
 295
 296 #endif /* CONFIG_OPTPROBES */
 297
 298 /* Get the kprobe at this addr (if any) - called with preemption disabled */
 299 struct kprobe *get_kprobe(void *addr);
 300 void kretprobe_hash_lock(struct task_struct *tsk,
 301                          struct hlist_head **head, unsigned long *flags);
 302 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
 303 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 304
 305 /* kprobe_running() will just return the current_kprobe on this CPU */
 306 static inline struct kprobe *kprobe_running(void)
 307 {
 308         return (__this_cpu_read(current_kprobe));
 309 }
 310
 311 static inline void reset_current_kprobe(void)
 312 {
 313         __this_cpu_write(current_kprobe, NULL);
 314 }
 315
 316 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 317 {
 318         return (&__get_cpu_var(kprobe_ctlblk));
 319 }
 320
 321 int register_kprobe(struct kprobe *p);
 322 void unregister_kprobe(struct kprobe *p);
 323 int register_kprobes(struct kprobe **kps, int num);
 324 void unregister_kprobes(struct kprobe **kps, int num);
 325 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 326 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 327 int register_jprobe(struct jprobe *p);
 328 void unregister_jprobe(struct jprobe *p);
 329 int register_jprobes(struct jprobe **jps, int num);
 330 void unregister_jprobes(struct jprobe **jps, int num);
 331 void jprobe_return(void);
 332 unsigned long arch_deref_entry_point(void *);
 333
 334 int register_kretprobe(struct kretprobe *rp);
 335 void unregister_kretprobe(struct kretprobe *rp);
 336 int register_kretprobes(struct kretprobe **rps, int num);
 337 void unregister_kretprobes(struct kretprobe **rps, int num);
 338
 339 void kprobe_flush_task(struct task_struct *tk);
 340 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 341
 342 int disable_kprobe(struct kprobe *kp);
 343 int enable_kprobe(struct kprobe *kp);
 344
 345 void dump_kprobe(struct kprobe *kp);
 346
 347 #else /* !CONFIG_KPROBES: */
 348
 349 static inline int kprobes_built_in(void)
 350 {
 351         return 0;
 352 }
 353 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 354 {
 355         return 0;
 356 }
 357 static inline struct kprobe *get_kprobe(void *addr)
 358 {
 359         return NULL;
 360 }
 361 static inline struct kprobe *kprobe_running(void)
 362 {
 363         return NULL;
 364 }
 365 static inline int register_kprobe(struct kprobe *p)
 366 {
 367         return -ENOSYS;
 368 }
 369 static inline int register_kprobes(struct kprobe **kps, int num)
 370 {
 371         return -ENOSYS;
 372 }
 373 static inline void unregister_kprobe(struct kprobe *p)
 374 {
 375 }
 376 static inline void unregister_kprobes(struct kprobe **kps, int num)
 377 {
 378 }
 379 static inline int register_jprobe(struct jprobe *p)
 380 {
 381         return -ENOSYS;
 382 }
 383 static inline int register_jprobes(struct jprobe **jps, int num)
 384 {
 385         return -ENOSYS;
 386 }
 387 static inline void unregister_jprobe(struct jprobe *p)
 388 {
 389 }
 390 static inline void unregister_jprobes(struct jprobe **jps, int num)
 391 {
 392 }
 393 static inline void jprobe_return(void)
 394 {
 395 }
 396 static inline int register_kretprobe(struct kretprobe *rp)
 397 {
 398         return -ENOSYS;
 399 }
 400 static inline int register_kretprobes(struct kretprobe **rps, int num)
 401 {
 402         return -ENOSYS;
 403 }
 404 static inline void unregister_kretprobe(struct kretprobe *rp)
 405 {
 406 }
 407 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 408 {
 409 }
 410 static inline void kprobe_flush_task(struct task_struct *tk)
 411 {
 412 }
 413 static inline int disable_kprobe(struct kprobe *kp)
 414 {
 415         return -ENOSYS;
 416 }
 417 static inline int enable_kprobe(struct kprobe *kp)
 418 {
 419         return -ENOSYS;
 420 }
 421 #endif /* CONFIG_KPROBES */
 422 static inline int disable_kretprobe(struct kretprobe *rp)
 423 {
 424         return disable_kprobe(&rp->kp);
 425 }
 426 static inline int enable_kretprobe(struct kretprobe *rp)
 427 {
 428         return enable_kprobe(&rp->kp);
 429 }
 430 static inline int disable_jprobe(struct jprobe *jp)
 431 {
 432         return disable_kprobe(&jp->kp);
 433 }
 434 static inline int enable_jprobe(struct jprobe *jp)
 435 {
 436         return enable_kprobe(&jp->kp);
 437 }
 438
 439 #endif /* _LINUX_KPROBES_H */