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