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
  53 struct kprobe;
  54 struct pt_regs;
  55 struct kretprobe;
  56 struct kretprobe_instance;
  57 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  58 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  59 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  60                                        unsigned long flags);
  61 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  62                                        int trapnr);
  63 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
  64                                     struct pt_regs *);
  65
  66 struct kprobe {
  67         struct hlist_node hlist;
  68
  69         /* list of kprobes for multi-handler support */
  70         struct list_head list;
  71
  72         /*count the number of times this probe was temporarily disarmed */
  73         unsigned long nmissed;
  74
  75         /* location of the probe point */
  76         kprobe_opcode_t *addr;
  77
  78         /* Allow user to indicate symbol name of the probe point */
  79         const char *symbol_name;
  80
  81         /* Offset into the symbol */
  82         unsigned int offset;
  83
  84         /* Called before addr is executed. */
  85         kprobe_pre_handler_t pre_handler;
  86
  87         /* Called after addr is executed, unless... */
  88         kprobe_post_handler_t post_handler;
  89
  90         /* ... called if executing addr causes a fault (eg. page fault).
  91          * Return 1 if it handled fault, otherwise kernel will see it. */
  92         kprobe_fault_handler_t fault_handler;
  93
  94         /* ... called if breakpoint trap occurs in probe handler.
  95          * Return 1 if it handled break, otherwise kernel will see it. */
  96         kprobe_break_handler_t break_handler;
  97
  98         /* Saved opcode (which has been replaced with breakpoint) */
  99         kprobe_opcode_t opcode;
 100
 101         /* copy of the original instruction */
 102         struct arch_specific_insn ainsn;
 103
 104         /* Indicates various status flags.  Protected by kprobe_mutex. */
 105         u32 flags;
 106 };
 107
 108 /* Kprobe status flags */
 109 #define KPROBE_FLAG_GONE        1 /* breakpoint has already gone */
 110
 111 static inline int kprobe_gone(struct kprobe *p)
 112 {
 113         return p->flags & KPROBE_FLAG_GONE;
 114 }
 115
 116 /*
 117  * Special probe type that uses setjmp-longjmp type tricks to resume
 118  * execution at a specified entry with a matching prototype corresponding
 119  * to the probed function - a trick to enable arguments to become
 120  * accessible seamlessly by probe handling logic.
 121  * Note:
 122  * Because of the way compilers allocate stack space for local variables
 123  * etc upfront, regardless of sub-scopes within a function, this mirroring
 124  * principle currently works only for probes placed on function entry points.
 125  */
 126 struct jprobe {
 127         struct kprobe kp;
 128         void *entry;    /* probe handling code to jump to */
 129 };
 130
 131 /* For backward compatibility with old code using JPROBE_ENTRY() */
 132 #define JPROBE_ENTRY(handler)   (handler)
 133
 134 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 135 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 136
 137 #ifdef CONFIG_KRETPROBES
 138 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 139                                    struct pt_regs *regs);
 140 extern int arch_trampoline_kprobe(struct kprobe *p);
 141 #else /* CONFIG_KRETPROBES */
 142 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 143                                         struct pt_regs *regs)
 144 {
 145 }
 146 static inline int arch_trampoline_kprobe(struct kprobe *p)
 147 {
 148         return 0;
 149 }
 150 #endif /* CONFIG_KRETPROBES */
 151 /*
 152  * Function-return probe -
 153  * Note:
 154  * User needs to provide a handler function, and initialize maxactive.
 155  * maxactive - The maximum number of instances of the probed function that
 156  * can be active concurrently.
 157  * nmissed - tracks the number of times the probed function's return was
 158  * ignored, due to maxactive being too low.
 159  *
 160  */
 161 struct kretprobe {
 162         struct kprobe kp;
 163         kretprobe_handler_t handler;
 164         kretprobe_handler_t entry_handler;
 165         int maxactive;
 166         int nmissed;
 167         size_t data_size;
 168         struct hlist_head free_instances;
 169         spinlock_t lock;
 170 };
 171
 172 struct kretprobe_instance {
 173         struct hlist_node hlist;
 174         struct kretprobe *rp;
 175         kprobe_opcode_t *ret_addr;
 176         struct task_struct *task;
 177         char data[0];
 178 };
 179
 180 struct kretprobe_blackpoint {
 181         const char *name;
 182         void *addr;
 183 };
 184
 185 struct kprobe_blackpoint {
 186         const char *name;
 187         unsigned long start_addr;
 188         unsigned long range;
 189 };
 190
 191 extern struct kretprobe_blackpoint kretprobe_blacklist[];
 192
 193 static inline void kretprobe_assert(struct kretprobe_instance *ri,
 194         unsigned long orig_ret_address, unsigned long trampoline_address)
 195 {
 196         if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
 197                 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
 198                                 ri->rp, ri->rp->kp.addr);
 199                 BUG();
 200         }
 201 }
 202
 203 #ifdef CONFIG_KPROBES_SANITY_TEST
 204 extern int init_test_probes(void);
 205 #else
 206 static inline int init_test_probes(void)
 207 {
 208         return 0;
 209 }
 210 #endif /* CONFIG_KPROBES_SANITY_TEST */
 211
 212 extern int arch_prepare_kprobe(struct kprobe *p);
 213 extern void arch_arm_kprobe(struct kprobe *p);
 214 extern void arch_disarm_kprobe(struct kprobe *p);
 215 extern int arch_init_kprobes(void);
 216 extern void show_registers(struct pt_regs *regs);
 217 extern kprobe_opcode_t *get_insn_slot(void);
 218 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
 219 extern void kprobes_inc_nmissed_count(struct kprobe *p);
 220
 221 /* Get the kprobe at this addr (if any) - called with preemption disabled */
 222 struct kprobe *get_kprobe(void *addr);
 223 void kretprobe_hash_lock(struct task_struct *tsk,
 224                          struct hlist_head **head, unsigned long *flags);
 225 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
 226 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 227
 228 /* kprobe_running() will just return the current_kprobe on this CPU */
 229 static inline struct kprobe *kprobe_running(void)
 230 {
 231         return (__get_cpu_var(current_kprobe));
 232 }
 233
 234 static inline void reset_current_kprobe(void)
 235 {
 236         __get_cpu_var(current_kprobe) = NULL;
 237 }
 238
 239 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 240 {
 241         return (&__get_cpu_var(kprobe_ctlblk));
 242 }
 243
 244 int register_kprobe(struct kprobe *p);
 245 void unregister_kprobe(struct kprobe *p);
 246 int register_kprobes(struct kprobe **kps, int num);
 247 void unregister_kprobes(struct kprobe **kps, int num);
 248 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 249 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 250 int register_jprobe(struct jprobe *p);
 251 void unregister_jprobe(struct jprobe *p);
 252 int register_jprobes(struct jprobe **jps, int num);
 253 void unregister_jprobes(struct jprobe **jps, int num);
 254 void jprobe_return(void);
 255 unsigned long arch_deref_entry_point(void *);
 256
 257 int register_kretprobe(struct kretprobe *rp);
 258 void unregister_kretprobe(struct kretprobe *rp);
 259 int register_kretprobes(struct kretprobe **rps, int num);
 260 void unregister_kretprobes(struct kretprobe **rps, int num);
 261
 262 void kprobe_flush_task(struct task_struct *tk);
 263 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 264
 265 #else /* CONFIG_KPROBES */
 266
 267 #define __kprobes       notrace
 268 struct jprobe;
 269 struct kretprobe;
 270
 271 static inline struct kprobe *get_kprobe(void *addr)
 272 {
 273         return NULL;
 274 }
 275 static inline struct kprobe *kprobe_running(void)
 276 {
 277         return NULL;
 278 }
 279 static inline int register_kprobe(struct kprobe *p)
 280 {
 281         return -ENOSYS;
 282 }
 283 static inline int register_kprobes(struct kprobe **kps, int num)
 284 {
 285         return -ENOSYS;
 286 }
 287 static inline void unregister_kprobe(struct kprobe *p)
 288 {
 289 }
 290 static inline void unregister_kprobes(struct kprobe **kps, int num)
 291 {
 292 }
 293 static inline int register_jprobe(struct jprobe *p)
 294 {
 295         return -ENOSYS;
 296 }
 297 static inline int register_jprobes(struct jprobe **jps, int num)
 298 {
 299         return -ENOSYS;
 300 }
 301 static inline void unregister_jprobe(struct jprobe *p)
 302 {
 303 }
 304 static inline void unregister_jprobes(struct jprobe **jps, int num)
 305 {
 306 }
 307 static inline void jprobe_return(void)
 308 {
 309 }
 310 static inline int register_kretprobe(struct kretprobe *rp)
 311 {
 312         return -ENOSYS;
 313 }
 314 static inline int register_kretprobes(struct kretprobe **rps, int num)
 315 {
 316         return -ENOSYS;
 317 }
 318 static inline void unregister_kretprobe(struct kretprobe *rp)
 319 {
 320 }
 321 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 322 {
 323 }
 324 static inline void kprobe_flush_task(struct task_struct *tk)
 325 {
 326 }
 327 #endif                          /* CONFIG_KPROBES */
 328 #endif                          /* _LINUX_KPROBES_H */