linux/include/linux/kprobes.h
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   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/*
  53 * If function tracer is enabled and the arch supports full
  54 * passing of pt_regs to function tracing, then kprobes can
  55 * optimize on top of function tracing.
  56 */
  57#if defined(CONFIG_FUNCTION_TRACER) && defined(ARCH_SUPPORTS_FTRACE_SAVE_REGS) \
  58        && defined(ARCH_SUPPORTS_KPROBES_ON_FTRACE)
  59# define KPROBES_CAN_USE_FTRACE
  60#endif
  61
  62/* Attach to insert probes on any functions which should be ignored*/
  63#define __kprobes       __attribute__((__section__(".kprobes.text")))
  64
  65#else /* CONFIG_KPROBES */
  66typedef int kprobe_opcode_t;
  67struct arch_specific_insn {
  68        int dummy;
  69};
  70#define __kprobes
  71
  72#endif /* CONFIG_KPROBES */
  73
  74struct kprobe;
  75struct pt_regs;
  76struct kretprobe;
  77struct kretprobe_instance;
  78typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  79typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  80typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  81                                       unsigned long flags);
  82typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  83                                       int trapnr);
  84typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
  85                                    struct pt_regs *);
  86
  87struct kprobe {
  88        struct hlist_node hlist;
  89
  90        /* list of kprobes for multi-handler support */
  91        struct list_head list;
  92
  93        /*count the number of times this probe was temporarily disarmed */
  94        unsigned long nmissed;
  95
  96        /* location of the probe point */
  97        kprobe_opcode_t *addr;
  98
  99        /* Allow user to indicate symbol name of the probe point */
 100        const char *symbol_name;
 101
 102        /* Offset into the symbol */
 103        unsigned int offset;
 104
 105        /* Called before addr is executed. */
 106        kprobe_pre_handler_t pre_handler;
 107
 108        /* Called after addr is executed, unless... */
 109        kprobe_post_handler_t post_handler;
 110
 111        /*
 112         * ... called if executing addr causes a fault (eg. page fault).
 113         * Return 1 if it handled fault, otherwise kernel will see it.
 114         */
 115        kprobe_fault_handler_t fault_handler;
 116
 117        /*
 118         * ... called if breakpoint trap occurs in probe handler.
 119         * Return 1 if it handled break, otherwise kernel will see it.
 120         */
 121        kprobe_break_handler_t break_handler;
 122
 123        /* Saved opcode (which has been replaced with breakpoint) */
 124        kprobe_opcode_t opcode;
 125
 126        /* copy of the original instruction */
 127        struct arch_specific_insn ainsn;
 128
 129        /*
 130         * Indicates various status flags.
 131         * Protected by kprobe_mutex after this kprobe is registered.
 132         */
 133        u32 flags;
 134};
 135
 136/* Kprobe status flags */
 137#define KPROBE_FLAG_GONE        1 /* breakpoint has already gone */
 138#define KPROBE_FLAG_DISABLED    2 /* probe is temporarily disabled */
 139#define KPROBE_FLAG_OPTIMIZED   4 /*
 140                                   * probe is really optimized.
 141                                   * NOTE:
 142                                   * this flag is only for optimized_kprobe.
 143                                   */
 144#define KPROBE_FLAG_FTRACE      8 /* probe is using ftrace */
 145
 146/* Has this kprobe gone ? */
 147static inline int kprobe_gone(struct kprobe *p)
 148{
 149        return p->flags & KPROBE_FLAG_GONE;
 150}
 151
 152/* Is this kprobe disabled ? */
 153static inline int kprobe_disabled(struct kprobe *p)
 154{
 155        return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
 156}
 157
 158/* Is this kprobe really running optimized path ? */
 159static inline int kprobe_optimized(struct kprobe *p)
 160{
 161        return p->flags & KPROBE_FLAG_OPTIMIZED;
 162}
 163
 164/* Is this kprobe uses ftrace ? */
 165static inline int kprobe_ftrace(struct kprobe *p)
 166{
 167        return p->flags & KPROBE_FLAG_FTRACE;
 168}
 169
 170/*
 171 * Special probe type that uses setjmp-longjmp type tricks to resume
 172 * execution at a specified entry with a matching prototype corresponding
 173 * to the probed function - a trick to enable arguments to become
 174 * accessible seamlessly by probe handling logic.
 175 * Note:
 176 * Because of the way compilers allocate stack space for local variables
 177 * etc upfront, regardless of sub-scopes within a function, this mirroring
 178 * principle currently works only for probes placed on function entry points.
 179 */
 180struct jprobe {
 181        struct kprobe kp;
 182        void *entry;    /* probe handling code to jump to */
 183};
 184
 185/* For backward compatibility with old code using JPROBE_ENTRY() */
 186#define JPROBE_ENTRY(handler)   (handler)
 187
 188/*
 189 * Function-return probe -
 190 * Note:
 191 * User needs to provide a handler function, and initialize maxactive.
 192 * maxactive - The maximum number of instances of the probed function that
 193 * can be active concurrently.
 194 * nmissed - tracks the number of times the probed function's return was
 195 * ignored, due to maxactive being too low.
 196 *
 197 */
 198struct kretprobe {
 199        struct kprobe kp;
 200        kretprobe_handler_t handler;
 201        kretprobe_handler_t entry_handler;
 202        int maxactive;
 203        int nmissed;
 204        size_t data_size;
 205        struct hlist_head free_instances;
 206        raw_spinlock_t lock;
 207};
 208
 209struct kretprobe_instance {
 210        struct hlist_node hlist;
 211        struct kretprobe *rp;
 212        kprobe_opcode_t *ret_addr;
 213        struct task_struct *task;
 214        char data[0];
 215};
 216
 217struct kretprobe_blackpoint {
 218        const char *name;
 219        void *addr;
 220};
 221
 222struct kprobe_blackpoint {
 223        const char *name;
 224        unsigned long start_addr;
 225        unsigned long range;
 226};
 227
 228#ifdef CONFIG_KPROBES
 229DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 230DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 231
 232/*
 233 * For #ifdef avoidance:
 234 */
 235static inline int kprobes_built_in(void)
 236{
 237        return 1;
 238}
 239
 240#ifdef CONFIG_KRETPROBES
 241extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 242                                   struct pt_regs *regs);
 243extern int arch_trampoline_kprobe(struct kprobe *p);
 244#else /* CONFIG_KRETPROBES */
 245static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 246                                        struct pt_regs *regs)
 247{
 248}
 249static inline int arch_trampoline_kprobe(struct kprobe *p)
 250{
 251        return 0;
 252}
 253#endif /* CONFIG_KRETPROBES */
 254
 255extern struct kretprobe_blackpoint kretprobe_blacklist[];
 256
 257static inline void kretprobe_assert(struct kretprobe_instance *ri,
 258        unsigned long orig_ret_address, unsigned long trampoline_address)
 259{
 260        if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
 261                printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
 262                                ri->rp, ri->rp->kp.addr);
 263                BUG();
 264        }
 265}
 266
 267#ifdef CONFIG_KPROBES_SANITY_TEST
 268extern int init_test_probes(void);
 269#else
 270static inline int init_test_probes(void)
 271{
 272        return 0;
 273}
 274#endif /* CONFIG_KPROBES_SANITY_TEST */
 275
 276extern int arch_prepare_kprobe(struct kprobe *p);
 277extern void arch_arm_kprobe(struct kprobe *p);
 278extern void arch_disarm_kprobe(struct kprobe *p);
 279extern int arch_init_kprobes(void);
 280extern void show_registers(struct pt_regs *regs);
 281extern kprobe_opcode_t *get_insn_slot(void);
 282extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
 283extern void kprobes_inc_nmissed_count(struct kprobe *p);
 284
 285#ifdef CONFIG_OPTPROBES
 286/*
 287 * Internal structure for direct jump optimized probe
 288 */
 289struct optimized_kprobe {
 290        struct kprobe kp;
 291        struct list_head list;  /* list for optimizing queue */
 292        struct arch_optimized_insn optinsn;
 293};
 294
 295/* Architecture dependent functions for direct jump optimization */
 296extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
 297extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
 298extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
 299extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
 300extern void arch_optimize_kprobes(struct list_head *oplist);
 301extern void arch_unoptimize_kprobes(struct list_head *oplist,
 302                                    struct list_head *done_list);
 303extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
 304extern kprobe_opcode_t *get_optinsn_slot(void);
 305extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
 306extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
 307                                        unsigned long addr);
 308
 309extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
 310
 311#ifdef CONFIG_SYSCTL
 312extern int sysctl_kprobes_optimization;
 313extern int proc_kprobes_optimization_handler(struct ctl_table *table,
 314                                             int write, void __user *buffer,
 315                                             size_t *length, loff_t *ppos);
 316#endif
 317
 318#endif /* CONFIG_OPTPROBES */
 319#ifdef KPROBES_CAN_USE_FTRACE
 320extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 321                                  struct ftrace_ops *ops, struct pt_regs *regs);
 322extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
 323#endif
 324
 325
 326/* Get the kprobe at this addr (if any) - called with preemption disabled */
 327struct kprobe *get_kprobe(void *addr);
 328void kretprobe_hash_lock(struct task_struct *tsk,
 329                         struct hlist_head **head, unsigned long *flags);
 330void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
 331struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 332
 333/* kprobe_running() will just return the current_kprobe on this CPU */
 334static inline struct kprobe *kprobe_running(void)
 335{
 336        return (__this_cpu_read(current_kprobe));
 337}
 338
 339static inline void reset_current_kprobe(void)
 340{
 341        __this_cpu_write(current_kprobe, NULL);
 342}
 343
 344static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 345{
 346        return (&__get_cpu_var(kprobe_ctlblk));
 347}
 348
 349int register_kprobe(struct kprobe *p);
 350void unregister_kprobe(struct kprobe *p);
 351int register_kprobes(struct kprobe **kps, int num);
 352void unregister_kprobes(struct kprobe **kps, int num);
 353int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 354int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 355int register_jprobe(struct jprobe *p);
 356void unregister_jprobe(struct jprobe *p);
 357int register_jprobes(struct jprobe **jps, int num);
 358void unregister_jprobes(struct jprobe **jps, int num);
 359void jprobe_return(void);
 360unsigned long arch_deref_entry_point(void *);
 361
 362int register_kretprobe(struct kretprobe *rp);
 363void unregister_kretprobe(struct kretprobe *rp);
 364int register_kretprobes(struct kretprobe **rps, int num);
 365void unregister_kretprobes(struct kretprobe **rps, int num);
 366
 367void kprobe_flush_task(struct task_struct *tk);
 368void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 369
 370int disable_kprobe(struct kprobe *kp);
 371int enable_kprobe(struct kprobe *kp);
 372
 373void dump_kprobe(struct kprobe *kp);
 374
 375#else /* !CONFIG_KPROBES: */
 376
 377static inline int kprobes_built_in(void)
 378{
 379        return 0;
 380}
 381static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 382{
 383        return 0;
 384}
 385static inline struct kprobe *get_kprobe(void *addr)
 386{
 387        return NULL;
 388}
 389static inline struct kprobe *kprobe_running(void)
 390{
 391        return NULL;
 392}
 393static inline int register_kprobe(struct kprobe *p)
 394{
 395        return -ENOSYS;
 396}
 397static inline int register_kprobes(struct kprobe **kps, int num)
 398{
 399        return -ENOSYS;
 400}
 401static inline void unregister_kprobe(struct kprobe *p)
 402{
 403}
 404static inline void unregister_kprobes(struct kprobe **kps, int num)
 405{
 406}
 407static inline int register_jprobe(struct jprobe *p)
 408{
 409        return -ENOSYS;
 410}
 411static inline int register_jprobes(struct jprobe **jps, int num)
 412{
 413        return -ENOSYS;
 414}
 415static inline void unregister_jprobe(struct jprobe *p)
 416{
 417}
 418static inline void unregister_jprobes(struct jprobe **jps, int num)
 419{
 420}
 421static inline void jprobe_return(void)
 422{
 423}
 424static inline int register_kretprobe(struct kretprobe *rp)
 425{
 426        return -ENOSYS;
 427}
 428static inline int register_kretprobes(struct kretprobe **rps, int num)
 429{
 430        return -ENOSYS;
 431}
 432static inline void unregister_kretprobe(struct kretprobe *rp)
 433{
 434}
 435static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 436{
 437}
 438static inline void kprobe_flush_task(struct task_struct *tk)
 439{
 440}
 441static inline int disable_kprobe(struct kprobe *kp)
 442{
 443        return -ENOSYS;
 444}
 445static inline int enable_kprobe(struct kprobe *kp)
 446{
 447        return -ENOSYS;
 448}
 449#endif /* CONFIG_KPROBES */
 450static inline int disable_kretprobe(struct kretprobe *rp)
 451{
 452        return disable_kprobe(&rp->kp);
 453}
 454static inline int enable_kretprobe(struct kretprobe *rp)
 455{
 456        return enable_kprobe(&rp->kp);
 457}
 458static inline int disable_jprobe(struct jprobe *jp)
 459{
 460        return disable_kprobe(&jp->kp);
 461}
 462static inline int enable_jprobe(struct jprobe *jp)
 463{
 464        return enable_kprobe(&jp->kp);
 465}
 466
 467#endif /* _LINUX_KPROBES_H */
 468
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