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"))) notrace
  52 #else /* CONFIG_KPROBES */
  53 typedef int kprobe_opcode_t;
  54 struct arch_specific_insn {
  55         int dummy;
  56 };
  57 #define __kprobes       notrace
  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         /* ... called if executing addr causes a fault (eg. page fault).
  98          * Return 1 if it handled fault, otherwise kernel will see it. */
  99         kprobe_fault_handler_t fault_handler;
 100
 101         /* ... called if breakpoint trap occurs in probe handler.
 102          * Return 1 if it handled break, otherwise kernel will see it. */
 103         kprobe_break_handler_t break_handler;
 104
 105         /* Saved opcode (which has been replaced with breakpoint) */
 106         kprobe_opcode_t opcode;
 107
 108         /* copy of the original instruction */
 109         struct arch_specific_insn ainsn;
 110
 111         /* Indicates various status flags.  Protected by kprobe_mutex. */
 112         u32 flags;
 113 };
 114
 115 /* Kprobe status flags */
 116 #define KPROBE_FLAG_GONE        1 /* breakpoint has already gone */
 117
 118 static inline int kprobe_gone(struct kprobe *p)
 119 {
 120         return p->flags & KPROBE_FLAG_GONE;
 121 }
 122
 123 /*
 124  * Special probe type that uses setjmp-longjmp type tricks to resume
 125  * execution at a specified entry with a matching prototype corresponding
 126  * to the probed function - a trick to enable arguments to become
 127  * accessible seamlessly by probe handling logic.
 128  * Note:
 129  * Because of the way compilers allocate stack space for local variables
 130  * etc upfront, regardless of sub-scopes within a function, this mirroring
 131  * principle currently works only for probes placed on function entry points.
 132  */
 133 struct jprobe {
 134         struct kprobe kp;
 135         void *entry;    /* probe handling code to jump to */
 136 };
 137
 138 /* For backward compatibility with old code using JPROBE_ENTRY() */
 139 #define JPROBE_ENTRY(handler)   (handler)
 140
 141 /*
 142  * Function-return probe -
 143  * Note:
 144  * User needs to provide a handler function, and initialize maxactive.
 145  * maxactive - The maximum number of instances of the probed function that
 146  * can be active concurrently.
 147  * nmissed - tracks the number of times the probed function's return was
 148  * ignored, due to maxactive being too low.
 149  *
 150  */
 151 struct kretprobe {
 152         struct kprobe kp;
 153         kretprobe_handler_t handler;
 154         kretprobe_handler_t entry_handler;
 155         int maxactive;
 156         int nmissed;
 157         size_t data_size;
 158         struct hlist_head free_instances;
 159         spinlock_t lock;
 160 };
 161
 162 struct kretprobe_instance {
 163         struct hlist_node hlist;
 164         struct kretprobe *rp;
 165         kprobe_opcode_t *ret_addr;
 166         struct task_struct *task;
 167         char data[0];
 168 };
 169
 170 struct kretprobe_blackpoint {
 171         const char *name;
 172         void *addr;
 173 };
 174
 175 struct kprobe_blackpoint {
 176         const char *name;
 177         unsigned long start_addr;
 178         unsigned long range;
 179 };
 180
 181 #ifdef CONFIG_KPROBES
 182 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 183 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 184
 185 /*
 186  * For #ifdef avoidance:
 187  */
 188 static inline int kprobes_built_in(void)
 189 {
 190         return 1;
 191 }
 192
 193 #ifdef CONFIG_KRETPROBES
 194 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 195                                    struct pt_regs *regs);
 196 extern int arch_trampoline_kprobe(struct kprobe *p);
 197 #else /* CONFIG_KRETPROBES */
 198 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 199                                         struct pt_regs *regs)
 200 {
 201 }
 202 static inline int arch_trampoline_kprobe(struct kprobe *p)
 203 {
 204         return 0;
 205 }
 206 #endif /* CONFIG_KRETPROBES */
 207
 208 extern struct kretprobe_blackpoint kretprobe_blacklist[];
 209
 210 static inline void kretprobe_assert(struct kretprobe_instance *ri,
 211         unsigned long orig_ret_address, unsigned long trampoline_address)
 212 {
 213         if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
 214                 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
 215                                 ri->rp, ri->rp->kp.addr);
 216                 BUG();
 217         }
 218 }
 219
 220 #ifdef CONFIG_KPROBES_SANITY_TEST
 221 extern int init_test_probes(void);
 222 #else
 223 static inline int init_test_probes(void)
 224 {
 225         return 0;
 226 }
 227 #endif /* CONFIG_KPROBES_SANITY_TEST */
 228
 229 extern int arch_prepare_kprobe(struct kprobe *p);
 230 extern void arch_arm_kprobe(struct kprobe *p);
 231 extern void arch_disarm_kprobe(struct kprobe *p);
 232 extern int arch_init_kprobes(void);
 233 extern void show_registers(struct pt_regs *regs);
 234 extern kprobe_opcode_t *get_insn_slot(void);
 235 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
 236 extern void kprobes_inc_nmissed_count(struct kprobe *p);
 237
 238 /* Get the kprobe at this addr (if any) - called with preemption disabled */
 239 struct kprobe *get_kprobe(void *addr);
 240 void kretprobe_hash_lock(struct task_struct *tsk,
 241                          struct hlist_head **head, unsigned long *flags);
 242 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
 243 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 244
 245 /* kprobe_running() will just return the current_kprobe on this CPU */
 246 static inline struct kprobe *kprobe_running(void)
 247 {
 248         return (__get_cpu_var(current_kprobe));
 249 }
 250
 251 static inline void reset_current_kprobe(void)
 252 {
 253         __get_cpu_var(current_kprobe) = NULL;
 254 }
 255
 256 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 257 {
 258         return (&__get_cpu_var(kprobe_ctlblk));
 259 }
 260
 261 int register_kprobe(struct kprobe *p);
 262 void unregister_kprobe(struct kprobe *p);
 263 int register_kprobes(struct kprobe **kps, int num);
 264 void unregister_kprobes(struct kprobe **kps, int num);
 265 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 266 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 267 int register_jprobe(struct jprobe *p);
 268 void unregister_jprobe(struct jprobe *p);
 269 int register_jprobes(struct jprobe **jps, int num);
 270 void unregister_jprobes(struct jprobe **jps, int num);
 271 void jprobe_return(void);
 272 unsigned long arch_deref_entry_point(void *);
 273
 274 int register_kretprobe(struct kretprobe *rp);
 275 void unregister_kretprobe(struct kretprobe *rp);
 276 int register_kretprobes(struct kretprobe **rps, int num);
 277 void unregister_kretprobes(struct kretprobe **rps, int num);
 278
 279 void kprobe_flush_task(struct task_struct *tk);
 280 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 281
 282 #else /* !CONFIG_KPROBES: */
 283
 284 static inline int kprobes_built_in(void)
 285 {
 286         return 0;
 287 }
 288 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 289 {
 290         return 0;
 291 }
 292 static inline struct kprobe *get_kprobe(void *addr)
 293 {
 294         return NULL;
 295 }
 296 static inline struct kprobe *kprobe_running(void)
 297 {
 298         return NULL;
 299 }
 300 static inline int register_kprobe(struct kprobe *p)
 301 {
 302         return -ENOSYS;
 303 }
 304 static inline int register_kprobes(struct kprobe **kps, int num)
 305 {
 306         return -ENOSYS;
 307 }
 308 static inline void unregister_kprobe(struct kprobe *p)
 309 {
 310 }
 311 static inline void unregister_kprobes(struct kprobe **kps, int num)
 312 {
 313 }
 314 static inline int register_jprobe(struct jprobe *p)
 315 {
 316         return -ENOSYS;
 317 }
 318 static inline int register_jprobes(struct jprobe **jps, int num)
 319 {
 320         return -ENOSYS;
 321 }
 322 static inline void unregister_jprobe(struct jprobe *p)
 323 {
 324 }
 325 static inline void unregister_jprobes(struct jprobe **jps, int num)
 326 {
 327 }
 328 static inline void jprobe_return(void)
 329 {
 330 }
 331 static inline int register_kretprobe(struct kretprobe *rp)
 332 {
 333         return -ENOSYS;
 334 }
 335 static inline int register_kretprobes(struct kretprobe **rps, int num)
 336 {
 337         return -ENOSYS;
 338 }
 339 static inline void unregister_kretprobe(struct kretprobe *rp)
 340 {
 341 }
 342 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 343 {
 344 }
 345 static inline void kprobe_flush_task(struct task_struct *tk)
 346 {
 347 }
 348 #endif /* CONFIG_KPROBES */
 349 #endif /* _LINUX_KPROBES_H */