text: #ifndef _ASM_X86_KPROBES_H
  #define _ASM_X86_KPROBES_H
  /*
   *  Kernel Probes (KProbes)
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   *
   * Copyright (C) IBM Corporation, 2002, 2004
   *
   * See arch/x86/kernel/kprobes.c for x86 kprobes history.
   */
  #include <linux/types.h>
  #include <linux/ptrace.h>
  #include <linux/percpu.h>
  #include <asm/insn.h>
  
  #define  __ARCH_WANT_KPROBES_INSN_SLOT
  
  struct pt_regs;
  struct kprobe;
  
  typedef u8 kprobe_opcode_t;
  #define BREAKPOINT_INSTRUCTION	0xcc
  #define RELATIVEJUMP_OPCODE 0xe9
  #define RELATIVEJUMP_SIZE 5
  #define RELATIVECALL_OPCODE 0xe8
  #define RELATIVE_ADDR_SIZE 4
  #define MAX_STACK_SIZE 64
  #define CUR_STACK_SIZE(ADDR) \
  	(current_top_of_stack() - (unsigned long)(ADDR))
  #define MIN_STACK_SIZE(ADDR)				\
  	(MAX_STACK_SIZE < CUR_STACK_SIZE(ADDR) ?	\
  	 MAX_STACK_SIZE : CUR_STACK_SIZE(ADDR))
  
  #define flush_insn_slot(p)	do { } while (0)
  
  /* optinsn template addresses */
  extern __visible kprobe_opcode_t optprobe_template_entry;
  extern __visible kprobe_opcode_t optprobe_template_val;
  extern __visible kprobe_opcode_t optprobe_template_call;
  extern __visible kprobe_opcode_t optprobe_template_end;
  #define MAX_OPTIMIZED_LENGTH (MAX_INSN_SIZE + RELATIVE_ADDR_SIZE)
  #define MAX_OPTINSN_SIZE 				\
  	(((unsigned long)&optprobe_template_end -	\
  	  (unsigned long)&optprobe_template_entry) +	\
  	 MAX_OPTIMIZED_LENGTH + RELATIVEJUMP_SIZE)
  
  extern const int kretprobe_blacklist_size;
  
  void arch_remove_kprobe(struct kprobe *p);
  asmlinkage void kretprobe_trampoline(void);
  
  /* Architecture specific copy of original instruction*/
  struct arch_specific_insn {
  	/* copy of the original instruction */
  	kprobe_opcode_t *insn;
  	/*
  	 * boostable = -1: This instruction type is not boostable.
  	 * boostable = 0: This instruction type is boostable.
  	 * boostable = 1: This instruction has been boosted: we have
  	 * added a relative jump after the instruction copy in insn,
  	 * so no single-step and fixup are needed (unless there's
  	 * a post_handler or break_handler).
  	 */
  	int boostable;
  	bool if_modifier;
  };
  
  struct arch_optimized_insn {
  	/* copy of the original instructions */
  	kprobe_opcode_t copied_insn[RELATIVE_ADDR_SIZE];
  	/* detour code buffer */
  	kprobe_opcode_t *insn;
  	/* the size of instructions copied to detour code buffer */
  	size_t size;
  };
  
  /* Return true (!0) if optinsn is prepared for optimization. */
  static inline int arch_prepared_optinsn(struct arch_optimized_insn *optinsn)
  {
  	return optinsn->size;
  }
  
  struct prev_kprobe {
  	struct kprobe *kp;
  	unsigned long status;
  	unsigned long old_flags;
  	unsigned long saved_flags;
  };
  
  /* per-cpu kprobe control block */
  struct kprobe_ctlblk {
  	unsigned long kprobe_status;
  	unsigned long kprobe_old_flags;
  	unsigned long kprobe_saved_flags;
  	unsigned long *jprobe_saved_sp;
  	struct pt_regs jprobe_saved_regs;
  	kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];
  	struct prev_kprobe prev_kprobe;
  };
  
  extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
  extern int kprobe_exceptions_notify(struct notifier_block *self,
  				    unsigned long val, void *data);
  extern int kprobe_int3_handler(struct pt_regs *regs);
  extern int kprobe_debug_handler(struct pt_regs *regs);
  #endif /* _ASM_X86_KPROBES_H */
  