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
  42#ifdef CONFIG_KPROBES
  43#include <asm/kprobes.h>
  44
  45/* kprobe_status settings */
  46#define KPROBE_HIT_ACTIVE       0x00000001
  47#define KPROBE_HIT_SS           0x00000002
  48#define KPROBE_REENTER          0x00000004
  49#define KPROBE_HIT_SSDONE       0x00000008
  50
  51/* Attach to insert probes on any functions which should be ignored*/
  52#define __kprobes       __attribute__((__section__(".kprobes.text")))
  53#else /* CONFIG_KPROBES */
  54typedef int kprobe_opcode_t;
  55struct arch_specific_insn {
  56        int dummy;
  57};
  58#define __kprobes
  59#endif /* CONFIG_KPROBES */
  60
  61struct kprobe;
  62struct pt_regs;
  63struct kretprobe;
  64struct kretprobe_instance;
  65typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
  66typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
  67typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  68                                       unsigned long flags);
  69typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  70                                       int trapnr);
  71typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
  72                                    struct pt_regs *);
  73
  74struct kprobe {
  75        struct hlist_node hlist;
  76
  77        /* list of kprobes for multi-handler support */
  78        struct list_head list;
  79
  80        /*count the number of times this probe was temporarily disarmed */
  81        unsigned long nmissed;
  82
  83        /* location of the probe point */
  84        kprobe_opcode_t *addr;
  85
  86        /* Allow user to indicate symbol name of the probe point */
  87        const char *symbol_name;
  88
  89        /* Offset into the symbol */
  90        unsigned int offset;
  91
  92        /* Called before addr is executed. */
  93        kprobe_pre_handler_t pre_handler;
  94
  95        /* Called after addr is executed, unless... */
  96        kprobe_post_handler_t post_handler;
  97
  98        /*
  99         * ... called if executing addr causes a fault (eg. page fault).
 100         * Return 1 if it handled fault, otherwise kernel will see it.
 101         */
 102        kprobe_fault_handler_t fault_handler;
 103
 104        /*
 105         * ... called if breakpoint trap occurs in probe handler.
 106         * Return 1 if it handled break, otherwise kernel will see it.
 107         */
 108        kprobe_break_handler_t break_handler;
 109
 110        /* Saved opcode (which has been replaced with breakpoint) */
 111        kprobe_opcode_t opcode;
 112
 113        /* copy of the original instruction */
 114        struct arch_specific_insn ainsn;
 115
 116        /*
 117         * Indicates various status flags.
 118         * Protected by kprobe_mutex after this kprobe is registered.
 119         */
 120        u32 flags;
 121};
 122
 123/* Kprobe status flags */
 124#define KPROBE_FLAG_GONE        1 /* breakpoint has already gone */
 125#define KPROBE_FLAG_DISABLED    2 /* probe is temporarily disabled */
 126#define KPROBE_FLAG_OPTIMIZED   4 /*
 127                                   * probe is really optimized.
 128                                   * NOTE:
 129                                   * this flag is only for optimized_kprobe.
 130                                   */
 131
 132/* Has this kprobe gone ? */
 133static inline int kprobe_gone(struct kprobe *p)
 134{
 135        return p->flags & KPROBE_FLAG_GONE;
 136}
 137
 138/* Is this kprobe disabled ? */
 139static inline int kprobe_disabled(struct kprobe *p)
 140{
 141        return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
 142}
 143
 144/* Is this kprobe really running optimized path ? */
 145static inline int kprobe_optimized(struct kprobe *p)
 146{
 147        return p->flags & KPROBE_FLAG_OPTIMIZED;
 148}
 149/*
 150 * Special probe type that uses setjmp-longjmp type tricks to resume
 151 * execution at a specified entry with a matching prototype corresponding
 152 * to the probed function - a trick to enable arguments to become
 153 * accessible seamlessly by probe handling logic.
 154 * Note:
 155 * Because of the way compilers allocate stack space for local variables
 156 * etc upfront, regardless of sub-scopes within a function, this mirroring
 157 * principle currently works only for probes placed on function entry points.
 158 */
 159struct jprobe {
 160        struct kprobe kp;
 161        void *entry;    /* probe handling code to jump to */
 162};
 163
 164/* For backward compatibility with old code using JPROBE_ENTRY() */
 165#define JPROBE_ENTRY(handler)   (handler)
 166
 167/*
 168 * Function-return probe -
 169 * Note:
 170 * User needs to provide a handler function, and initialize maxactive.
 171 * maxactive - The maximum number of instances of the probed function that
 172 * can be active concurrently.
 173 * nmissed - tracks the number of times the probed function's return was
 174 * ignored, due to maxactive being too low.
 175 *
 176 */
 177struct kretprobe {
 178        struct kprobe kp;
 179        kretprobe_handler_t handler;
 180        kretprobe_handler_t entry_handler;
 181        int maxactive;
 182        int nmissed;
 183        size_t data_size;
 184        struct hlist_head free_instances;
 185        raw_spinlock_t lock;
 186};
 187
 188struct kretprobe_instance {
 189        struct hlist_node hlist;
 190        struct kretprobe *rp;
 191        kprobe_opcode_t *ret_addr;
 192        struct task_struct *task;
 193        char data[0];
 194};
 195
 196struct kretprobe_blackpoint {
 197        const char *name;
 198        void *addr;
 199};
 200
 201struct kprobe_blackpoint {
 202        const char *name;
 203        unsigned long start_addr;
 204        unsigned long range;
 205};
 206
 207#ifdef CONFIG_KPROBES
 208DECLARE_PER_CPU(struct kprobe *, current_kprobe);
 209DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 210
 211/*
 212 * For #ifdef avoidance:
 213 */
 214static inline int kprobes_built_in(void)
 215{
 216        return 1;
 217}
 218
 219#ifdef CONFIG_KRETPROBES
 220extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
 221                                   struct pt_regs *regs);
 222extern int arch_trampoline_kprobe(struct kprobe *p);
 223#else /* CONFIG_KRETPROBES */
 224static inline void arch_prepare_kretprobe(struct kretprobe *rp,
 225                                        struct pt_regs *regs)
 226{
 227}
 228static inline int arch_trampoline_kprobe(struct kprobe *p)
 229{
 230        return 0;
 231}
 232#endif /* CONFIG_KRETPROBES */
 233
 234extern struct kretprobe_blackpoint kretprobe_blacklist[];
 235
 236static inline void kretprobe_assert(struct kretprobe_instance *ri,
 237        unsigned long orig_ret_address, unsigned long trampoline_address)
 238{
 239        if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
 240                printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
 241                                ri->rp, ri->rp->kp.addr);
 242                BUG();
 243        }
 244}
 245
 246#ifdef CONFIG_KPROBES_SANITY_TEST
 247extern int init_test_probes(void);
 248#else
 249static inline int init_test_probes(void)
 250{
 251        return 0;
 252}
 253#endif /* CONFIG_KPROBES_SANITY_TEST */
 254
 255extern int arch_prepare_kprobe(struct kprobe *p);
 256extern void arch_arm_kprobe(struct kprobe *p);
 257extern void arch_disarm_kprobe(struct kprobe *p);
 258extern int arch_init_kprobes(void);
 259extern void show_registers(struct pt_regs *regs);
 260extern kprobe_opcode_t *get_insn_slot(void);
 261extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
 262extern void kprobes_inc_nmissed_count(struct kprobe *p);
 263
 264#ifdef CONFIG_OPTPROBES
 265/*
 266 * Internal structure for direct jump optimized probe
 267 */
 268struct optimized_kprobe {
 269        struct kprobe kp;
 270        struct list_head list;  /* list for optimizing queue */
 271        struct arch_optimized_insn optinsn;
 272};
 273
 274/* Architecture dependent functions for direct jump optimization */
 275extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
 276extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
 277extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
 278extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
 279extern void arch_optimize_kprobes(struct list_head *oplist);
 280extern void arch_unoptimize_kprobes(struct list_head *oplist,
 281                                    struct list_head *done_list);
 282extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
 283extern kprobe_opcode_t *get_optinsn_slot(void);
 284extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
 285extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
 286                                        unsigned long addr);
 287
 288extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
 289
 290#ifdef CONFIG_SYSCTL
 291extern int sysctl_kprobes_optimization;
 292extern int proc_kprobes_optimization_handler(struct ctl_table *table,
 293                                             int write, void __user *buffer,
 294                                             size_t *length, loff_t *ppos);
 295#endif
 296
 297#endif /* CONFIG_OPTPROBES */
 298
 299/* Get the kprobe at this addr (if any) - called with preemption disabled */
 300struct kprobe *get_kprobe(void *addr);
 301void kretprobe_hash_lock(struct task_struct *tsk,
 302                         struct hlist_head **head, unsigned long *flags);
 303void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
 304struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
 305
 306/* kprobe_running() will just return the current_kprobe on this CPU */
 307static inline struct kprobe *kprobe_running(void)
 308{
 309        return (__this_cpu_read(current_kprobe));
 310}
 311
 312static inline void reset_current_kprobe(void)
 313{
 314        __this_cpu_write(current_kprobe, NULL);
 315}
 316
 317static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
 318{
 319        return (&__get_cpu_var(kprobe_ctlblk));
 320}
 321
 322int register_kprobe(struct kprobe *p);
 323void unregister_kprobe(struct kprobe *p);
 324int register_kprobes(struct kprobe **kps, int num);
 325void unregister_kprobes(struct kprobe **kps, int num);
 326int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
 327int longjmp_break_handler(struct kprobe *, struct pt_regs *);
 328int register_jprobe(struct jprobe *p);
 329void unregister_jprobe(struct jprobe *p);
 330int register_jprobes(struct jprobe **jps, int num);
 331void unregister_jprobes(struct jprobe **jps, int num);
 332void jprobe_return(void);
 333unsigned long arch_deref_entry_point(void *);
 334
 335int register_kretprobe(struct kretprobe *rp);
 336void unregister_kretprobe(struct kretprobe *rp);
 337int register_kretprobes(struct kretprobe **rps, int num);
 338void unregister_kretprobes(struct kretprobe **rps, int num);
 339
 340void kprobe_flush_task(struct task_struct *tk);
 341void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 342
 343int disable_kprobe(struct kprobe *kp);
 344int enable_kprobe(struct kprobe *kp);
 345
 346void dump_kprobe(struct kprobe *kp);
 347
 348#else /* !CONFIG_KPROBES: */
 349
 350static inline int kprobes_built_in(void)
 351{
 352        return 0;
 353}
 354static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 355{
 356        return 0;
 357}
 358static inline struct kprobe *get_kprobe(void *addr)
 359{
 360        return NULL;
 361}
 362static inline struct kprobe *kprobe_running(void)
 363{
 364        return NULL;
 365}
 366static inline int register_kprobe(struct kprobe *p)
 367{
 368        return -ENOSYS;
 369}
 370static inline int register_kprobes(struct kprobe **kps, int num)
 371{
 372        return -ENOSYS;
 373}
 374static inline void unregister_kprobe(struct kprobe *p)
 375{
 376}
 377static inline void unregister_kprobes(struct kprobe **kps, int num)
 378{
 379}
 380static inline int register_jprobe(struct jprobe *p)
 381{
 382        return -ENOSYS;
 383}
 384static inline int register_jprobes(struct jprobe **jps, int num)
 385{
 386        return -ENOSYS;
 387}
 388static inline void unregister_jprobe(struct jprobe *p)
 389{
 390}
 391static inline void unregister_jprobes(struct jprobe **jps, int num)
 392{
 393}
 394static inline void jprobe_return(void)
 395{
 396}
 397static inline int register_kretprobe(struct kretprobe *rp)
 398{
 399        return -ENOSYS;
 400}
 401static inline int register_kretprobes(struct kretprobe **rps, int num)
 402{
 403        return -ENOSYS;
 404}
 405static inline void unregister_kretprobe(struct kretprobe *rp)
 406{
 407}
 408static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 409{
 410}
 411static inline void kprobe_flush_task(struct task_struct *tk)
 412{
 413}
 414static inline int disable_kprobe(struct kprobe *kp)
 415{
 416        return -ENOSYS;
 417}
 418static inline int enable_kprobe(struct kprobe *kp)
 419{
 420        return -ENOSYS;
 421}
 422#endif /* CONFIG_KPROBES */
 423static inline int disable_kretprobe(struct kretprobe *rp)
 424{
 425        return disable_kprobe(&rp->kp);
 426}
 427static inline int enable_kretprobe(struct kretprobe *rp)
 428{
 429        return enable_kprobe(&rp->kp);
 430}
 431static inline int disable_jprobe(struct jprobe *jp)
 432{
 433        return disable_kprobe(&jp->kp);
 434}
 435static inline int enable_jprobe(struct jprobe *jp)
 436{
 437        return enable_kprobe(&jp->kp);
 438}
 439
 440#endif /* _LINUX_KPROBES_H */
 441
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