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 /* Attach to insert probes on any functions which should be ignored*/
  53 #define __kprobes       __attribute__((__section__(".kprobes.text")))
  54
  55 #else /* CONFIG_KPROBES */
  56 typedef int kprobe_opcode_t;
  57 struct arch_specific_insn {
  58         int dummy;
  59 };
  60 #define __kprobes
  61
  62 #endif /* CONFIG_KPROBES */
  63
  64 struct kprobe;
  65 struct pt_regs;
  66 struct kretprobe;
  67 struct kretprobe_instance;
  68 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  69 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  70 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  71                                        unsigned long flags);
  72 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  73                                        int trapnr);
  74 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
  75                                     struct pt_regs *);
  76
  77 struct kprobe {
  78         struct hlist_node hlist;
  79
  80         /* list of kprobes for multi-handler support */
  81         struct list_head list;
  82
  83         /*count the number of times this probe was temporarily disarmed */
  84         unsigned long nmissed;
  85
  86         /* location of the probe point */
  87         kprobe_opcode_t *addr;
  88
  89         /* Allow user to indicate symbol name of the probe point */
  90         const char *symbol_name;
  91
  92         /* Offset into the symbol */
  93         unsigned int offset;
  94
  95         /* Called before addr is executed. */
  96         kprobe_pre_handler_t pre_handler;
  97
  98         /* Called after addr is executed, unless... */
  99         kprobe_post_handler_t post_handler;
 100
 101         /*
 102          * ... called if executing addr causes a fault (eg. page fault).
 103          * Return 1 if it handled fault, otherwise kernel will see it.
 104          */
 105         kprobe_fault_handler_t fault_handler;
 106
 107         /*
 108          * ... called if breakpoint trap occurs in probe handler.
 109          * Return 1 if it handled break, otherwise kernel will see it.
 110          */
 111         kprobe_break_handler_t break_handler;
 112
 113         /* Saved opcode (which has been replaced with breakpoint) */
 114         kprobe_opcode_t opcode;
 115
 116         /* copy of the original instruction */
 117         struct arch_specific_insn ainsn;
 118
 119         /*
 120          * Indicates various status flags.
 121          * Protected by kprobe_mutex after this kprobe is registered.
 122          */
 123         u32 flags;
 124 };
 125
 126 /* Kprobe status flags */
 127 #define KPROBE_FLAG_GONE        1 /* breakpoint has already gone */
 128 #define KPROBE_FLAG_DISABLED    2 /* probe is temporarily disabled */
 129 #define KPROBE_FLAG_OPTIMIZED   4 /*
 130                                    * probe is really optimized.
 131                                    * NOTE:
 132                                    * this flag is only for optimized_kprobe.
 133                                    */
 134 #define KPROBE_FLAG_FTRACE      8 /* probe is using ftrace */
 135
 136 /* Has this kprobe gone ? */
 137 static inline int kprobe_gone(struct kprobe *p)
 138 {
 139         return p->flags & KPROBE_FLAG_GONE;
 140 }
 141
 142 /* Is this kprobe disabled ? */
 143 static inline int kprobe_disabled(struct kprobe *p)
 144 {
 145         return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
 146 }
 147
 148 /* Is this kprobe really running optimized path ? */
 149 static inline int kprobe_optimized(struct kprobe *p)
 150 {
 151         return p->flags & KPROBE_FLAG_OPTIMIZED;
 152 }
 153
 154 /* Is this kprobe uses ftrace ? */
 155 static inline int kprobe_ftrace(struct kprobe *p)
 156 {
 157         return p->flags & KPROBE_FLAG_FTRACE;
 158 }
 159
 160 /*
 161  * Special probe type that uses setjmp-longjmp type tricks to resume
 162  * execution at a specified entry with a matching prototype corresponding
 163  * to the probed function - a trick to enable arguments to become
 164  * accessible seamlessly by probe handling logic.
 165  * Note:
 166  * Because of the way compilers allocate stack space for local variables
 167  * etc upfront, regardless of sub-scopes within a function, this mirroring
 168  * principle currently works only for probes placed on function entry points.
 169  */
 170 struct jprobe {
 171         struct kprobe kp;
 172         void *entry;    /* probe handling code to jump to */
 173 };
 174
 175 /* For backward compatibility with old code using JPROBE_ENTRY() */
 176 #define JPROBE_ENTRY(handler)   (handler)
 177
 178 /*
 179  * Function-return probe -
 180  * Note:
 181  * User needs to provide a handler function, and initialize maxactive.
 182  * maxactive - The maximum number of instances of the probed function that
 183  * can be active concurrently.
 184  * nmissed - tracks the number of times the probed function's return was
 185  * ignored, due to maxactive being too low.
 186  *
 187  */
 188 struct kretprobe {
 189         struct kprobe kp;
 190         kretprobe_handler_t handler;
 191         kretprobe_handler_t entry_handler;
 192         int maxactive;
 193         int nmissed;
 194         size_t data_size;
 195         struct hlist_head free_instances;
 196         raw_spinlock_t lock;
 197 };
 198
 199 struct kretprobe_instance {
 200         struct hlist_node hlist;
 201         struct kretprobe *rp;
 202         kprobe_opcode_t *ret_addr;
 203         struct task_struct *task;
 204         char data[0];
 205 };
 206
 207 struct kretprobe_blackpoint {
 208         const char *name;
 209         void *addr;
 210 };
 211
 212 struct kprobe_blackpoint {
 213         const char *name;
 214         unsigned long start_addr;
 215         unsigned long range;
 216 };
 217
 218 #ifdef CONFIG_KPROBES
 219 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 220 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 221
 222 /*
 223  * For #ifdef avoidance:
 224  */
 225 static inline int kprobes_built_in(void)
 226 {
 227         return 1;
 228 }
 229
 230 #ifdef CONFIG_KRETPROBES
 231 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 232                                    struct pt_regs *regs);
 233 extern int arch_trampoline_kprobe(struct kprobe *p);
 234 #else /* CONFIG_KRETPROBES */
 235 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 236                                         struct pt_regs *regs)
 237 {
 238 }
 239 static inline int arch_trampoline_kprobe(struct kprobe *p)
 240 {
 241         return 0;
 242 }
 243 #endif /* CONFIG_KRETPROBES */
 244
 245 extern struct kretprobe_blackpoint kretprobe_blacklist[];
 246
 247 static inline void kretprobe_assert(struct kretprobe_instance *ri,
 248         unsigned long orig_ret_address, unsigned long trampoline_address)
 249 {
 250         if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
 251                 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
 252                                 ri->rp, ri->rp->kp.addr);
 253                 BUG();
 254         }
 255 }
 256
 257 #ifdef CONFIG_KPROBES_SANITY_TEST
 258 extern int init_test_probes(void);
 259 #else
 260 static inline int init_test_probes(void)
 261 {
 262         return 0;
 263 }
 264 #endif /* CONFIG_KPROBES_SANITY_TEST */
 265
 266 extern int arch_prepare_kprobe(struct kprobe *p);
 267 extern void arch_arm_kprobe(struct kprobe *p);
 268 extern void arch_disarm_kprobe(struct kprobe *p);
 269 extern int arch_init_kprobes(void);
 270 extern void show_registers(struct pt_regs *regs);
 271 extern kprobe_opcode_t *get_insn_slot(void);
 272 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
 273 extern void kprobes_inc_nmissed_count(struct kprobe *p);
 274
 275 #ifdef CONFIG_OPTPROBES
 276 /*
 277  * Internal structure for direct jump optimized probe
 278  */
 279 struct optimized_kprobe {
 280         struct kprobe kp;
 281         struct list_head list;  /* list for optimizing queue */
 282         struct arch_optimized_insn optinsn;
 283 };
 284
 285 /* Architecture dependent functions for direct jump optimization */
 286 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
 287 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
 288 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
 289 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
 290 extern void arch_optimize_kprobes(struct list_head *oplist);
 291 extern void arch_unoptimize_kprobes(struct list_head *oplist,
 292                                     struct list_head *done_list);
 293 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
 294 extern kprobe_opcode_t *get_optinsn_slot(void);
 295 extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
 296 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
 297                                         unsigned long addr);
 298
 299 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
 300
 301 #ifdef CONFIG_SYSCTL
 302 extern int sysctl_kprobes_optimization;
 303 extern int proc_kprobes_optimization_handler(struct ctl_table *table,
 304                                              int write, void __user *buffer,
 305                                              size_t *length, loff_t *ppos);
 306 #endif
 307
 308 #endif /* CONFIG_OPTPROBES */
 309 #ifdef CONFIG_KPROBES_ON_FTRACE
 310 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 311                                   struct ftrace_ops *ops, struct pt_regs *regs);
 312 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
 313 #endif
 314
 315
 316 /* Get the kprobe at this addr (if any) - called with preemption disabled */
 317 struct kprobe *get_kprobe(void *addr);
 318 void kretprobe_hash_lock(struct task_struct *tsk,
 319                          struct hlist_head **head, unsigned long *flags);
 320 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
 321 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 322
 323 /* kprobe_running() will just return the current_kprobe on this CPU */
 324 static inline struct kprobe *kprobe_running(void)
 325 {
 326         return (__this_cpu_read(current_kprobe));
 327 }
 328
 329 static inline void reset_current_kprobe(void)
 330 {
 331         __this_cpu_write(current_kprobe, NULL);
 332 }
 333
 334 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 335 {
 336         return (&__get_cpu_var(kprobe_ctlblk));
 337 }
 338
 339 int register_kprobe(struct kprobe *p);
 340 void unregister_kprobe(struct kprobe *p);
 341 int register_kprobes(struct kprobe **kps, int num);
 342 void unregister_kprobes(struct kprobe **kps, int num);
 343 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 344 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 345 int register_jprobe(struct jprobe *p);
 346 void unregister_jprobe(struct jprobe *p);
 347 int register_jprobes(struct jprobe **jps, int num);
 348 void unregister_jprobes(struct jprobe **jps, int num);
 349 void jprobe_return(void);
 350 unsigned long arch_deref_entry_point(void *);
 351
 352 int register_kretprobe(struct kretprobe *rp);
 353 void unregister_kretprobe(struct kretprobe *rp);
 354 int register_kretprobes(struct kretprobe **rps, int num);
 355 void unregister_kretprobes(struct kretprobe **rps, int num);
 356
 357 void kprobe_flush_task(struct task_struct *tk);
 358 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 359
 360 int disable_kprobe(struct kprobe *kp);
 361 int enable_kprobe(struct kprobe *kp);
 362
 363 void dump_kprobe(struct kprobe *kp);
 364
 365 #else /* !CONFIG_KPROBES: */
 366
 367 static inline int kprobes_built_in(void)
 368 {
 369         return 0;
 370 }
 371 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 372 {
 373         return 0;
 374 }
 375 static inline struct kprobe *get_kprobe(void *addr)
 376 {
 377         return NULL;
 378 }
 379 static inline struct kprobe *kprobe_running(void)
 380 {
 381         return NULL;
 382 }
 383 static inline int register_kprobe(struct kprobe *p)
 384 {
 385         return -ENOSYS;
 386 }
 387 static inline int register_kprobes(struct kprobe **kps, int num)
 388 {
 389         return -ENOSYS;
 390 }
 391 static inline void unregister_kprobe(struct kprobe *p)
 392 {
 393 }
 394 static inline void unregister_kprobes(struct kprobe **kps, int num)
 395 {
 396 }
 397 static inline int register_jprobe(struct jprobe *p)
 398 {
 399         return -ENOSYS;
 400 }
 401 static inline int register_jprobes(struct jprobe **jps, int num)
 402 {
 403         return -ENOSYS;
 404 }
 405 static inline void unregister_jprobe(struct jprobe *p)
 406 {
 407 }
 408 static inline void unregister_jprobes(struct jprobe **jps, int num)
 409 {
 410 }
 411 static inline void jprobe_return(void)
 412 {
 413 }
 414 static inline int register_kretprobe(struct kretprobe *rp)
 415 {
 416         return -ENOSYS;
 417 }
 418 static inline int register_kretprobes(struct kretprobe **rps, int num)
 419 {
 420         return -ENOSYS;
 421 }
 422 static inline void unregister_kretprobe(struct kretprobe *rp)
 423 {
 424 }
 425 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 426 {
 427 }
 428 static inline void kprobe_flush_task(struct task_struct *tk)
 429 {
 430 }
 431 static inline int disable_kprobe(struct kprobe *kp)
 432 {
 433         return -ENOSYS;
 434 }
 435 static inline int enable_kprobe(struct kprobe *kp)
 436 {
 437         return -ENOSYS;
 438 }
 439 #endif /* CONFIG_KPROBES */
 440 static inline int disable_kretprobe(struct kretprobe *rp)
 441 {
 442         return disable_kprobe(&rp->kp);
 443 }
 444 static inline int enable_kretprobe(struct kretprobe *rp)
 445 {
 446         return enable_kprobe(&rp->kp);
 447 }
 448 static inline int disable_jprobe(struct jprobe *jp)
 449 {
 450         return disable_kprobe(&jp->kp);
 451 }
 452 static inline int enable_jprobe(struct jprobe *jp)
 453 {
 454         return enable_kprobe(&jp->kp);
 455 }
 456
 457 #endif /* _LINUX_KPROBES_H */