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