/* SPDX-License-Identifier: GPL-2.0-or-later */

  #ifndef _LINUX_KPROBES_H
  #define _LINUX_KPROBES_H
  /*
   *  Kernel Probes (KProbes)
   *  include/linux/kprobes.h
   *

   * Copyright (C) IBM Corporation, 2002, 2004
   *
   * 2002-Oct	Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
   *		Probes initial implementation ( includes suggestions from
   *		Rusty Russell).
   * 2004-July	Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
   *		interface to access function arguments.

   * 2005-May	Hien Nguyen <hien@us.ibm.com> and Jim Keniston
   *		<jkenisto@us.ibm.com>  and Prasanna S Panchamukhi
   *		<prasanna@in.ibm.com> added function-return probes.

   */

  #include <linux/compiler.h>

  #include <linux/linkage.h>

  #include <linux/list.h>
  #include <linux/notifier.h>
  #include <linux/smp.h>

  #include <linux/bug.h>

  #include <linux/percpu.h>

  #include <linux/spinlock.h>
  #include <linux/rcupdate.h>

  #include <linux/mutex.h>

  #include <linux/ftrace.h>

  #include <asm/kprobes.h>

  #ifdef CONFIG_KPROBES

  /* kprobe_status settings */
  #define KPROBE_HIT_ACTIVE	0x00000001
  #define KPROBE_HIT_SS		0x00000002
  #define KPROBE_REENTER		0x00000004
  #define KPROBE_HIT_SSDONE	0x00000008

  #else /* CONFIG_KPROBES */

  #include <asm-generic/kprobes.h>

  typedef int kprobe_opcode_t;
  struct arch_specific_insn {
  	int dummy;
  };

  #endif /* CONFIG_KPROBES */

  struct kprobe;
  struct pt_regs;

  struct kretprobe;
  struct kretprobe_instance;

  typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);

  typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
  				       unsigned long flags);
  typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
  				       int trapnr);

  typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
  				    struct pt_regs *);

  struct kprobe {
  	struct hlist_node hlist;

  	/* list of kprobes for multi-handler support */
  	struct list_head list;

  	/*count the number of times this probe was temporarily disarmed */
  	unsigned long nmissed;

  	/* location of the probe point */
  	kprobe_opcode_t *addr;

  	/* Allow user to indicate symbol name of the probe point */

  	const char *symbol_name;

  
  	/* Offset into the symbol */
  	unsigned int offset;

  	/* Called before addr is executed. */
  	kprobe_pre_handler_t pre_handler;
  
  	/* Called after addr is executed, unless... */
  	kprobe_post_handler_t post_handler;

  	/*
  	 * ... called if executing addr causes a fault (eg. page fault).
  	 * Return 1 if it handled fault, otherwise kernel will see it.
  	 */

  	kprobe_fault_handler_t fault_handler;

  	/* Saved opcode (which has been replaced with breakpoint) */
  	kprobe_opcode_t opcode;
  
  	/* copy of the original instruction */
  	struct arch_specific_insn ainsn;

  	/*
  	 * Indicates various status flags.
  	 * Protected by kprobe_mutex after this kprobe is registered.
  	 */

  	u32 flags;

  };

  /* Kprobe status flags */
  #define KPROBE_FLAG_GONE	1 /* breakpoint has already gone */

  #define KPROBE_FLAG_DISABLED	2 /* probe is temporarily disabled */

  #define KPROBE_FLAG_OPTIMIZED	4 /*
  				   * probe is really optimized.
  				   * NOTE:
  				   * this flag is only for optimized_kprobe.
  				   */

  #define KPROBE_FLAG_FTRACE	8 /* probe is using ftrace */

  /* Has this kprobe gone ? */

  static inline int kprobe_gone(struct kprobe *p)
  {
  	return p->flags & KPROBE_FLAG_GONE;
  }

  /* Is this kprobe disabled ? */
  static inline int kprobe_disabled(struct kprobe *p)
  {
  	return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
  }

  
  /* Is this kprobe really running optimized path ? */
  static inline int kprobe_optimized(struct kprobe *p)
  {
  	return p->flags & KPROBE_FLAG_OPTIMIZED;
  }

  
  /* Is this kprobe uses ftrace ? */
  static inline int kprobe_ftrace(struct kprobe *p)
  {
  	return p->flags & KPROBE_FLAG_FTRACE;
  }

  /*

   * Function-return probe -
   * Note:
   * User needs to provide a handler function, and initialize maxactive.
   * maxactive - The maximum number of instances of the probed function that
   * can be active concurrently.
   * nmissed - tracks the number of times the probed function's return was
   * ignored, due to maxactive being too low.
   *
   */
  struct kretprobe {
  	struct kprobe kp;
  	kretprobe_handler_t handler;

  	kretprobe_handler_t entry_handler;

  	int maxactive;
  	int nmissed;

  	size_t data_size;

  	struct hlist_head free_instances;

  	raw_spinlock_t lock;

  };
  
  struct kretprobe_instance {

  	union {
  		struct hlist_node hlist;
  		struct rcu_head rcu;
  	};

  	struct kretprobe *rp;

  	kprobe_opcode_t *ret_addr;
  	struct task_struct *task;

  	void *fp;

  	char data[];

  };

  struct kretprobe_blackpoint {
  	const char *name;
  	void *addr;
  };

  struct kprobe_blacklist_entry {
  	struct list_head list;

  	unsigned long start_addr;

  	unsigned long end_addr;

  };

  #ifdef CONFIG_KPROBES
  DECLARE_PER_CPU(struct kprobe *, current_kprobe);
  DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

  /*
   * For #ifdef avoidance:
   */
  static inline int kprobes_built_in(void)
  {
  	return 1;
  }

  extern void kprobe_busy_begin(void);
  extern void kprobe_busy_end(void);

  #ifdef CONFIG_KRETPROBES
  extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
  				   struct pt_regs *regs);
  extern int arch_trampoline_kprobe(struct kprobe *p);

  
  /* If the trampoline handler called from a kprobe, use this version */
  unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
  				void *trampoline_address,
  				void *frame_pointer);
  
  static nokprobe_inline
  unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
  				void *trampoline_address,
  				void *frame_pointer)
  {
  	unsigned long ret;
  	/*
  	 * Set a dummy kprobe for avoiding kretprobe recursion.
  	 * Since kretprobe never runs in kprobe handler, no kprobe must
  	 * be running at this point.
  	 */
  	kprobe_busy_begin();
  	ret = __kretprobe_trampoline_handler(regs, trampoline_address, frame_pointer);
  	kprobe_busy_end();
  
  	return ret;
  }

  #else /* CONFIG_KRETPROBES */
  static inline void arch_prepare_kretprobe(struct kretprobe *rp,
  					struct pt_regs *regs)
  {
  }
  static inline int arch_trampoline_kprobe(struct kprobe *p)
  {
  	return 0;
  }
  #endif /* CONFIG_KRETPROBES */

  extern struct kretprobe_blackpoint kretprobe_blacklist[];

  #ifdef CONFIG_KPROBES_SANITY_TEST
  extern int init_test_probes(void);
  #else
  static inline int init_test_probes(void)
  {
  	return 0;
  }
  #endif /* CONFIG_KPROBES_SANITY_TEST */

  extern int arch_prepare_kprobe(struct kprobe *p);

  extern void arch_arm_kprobe(struct kprobe *p);
  extern void arch_disarm_kprobe(struct kprobe *p);

  extern int arch_init_kprobes(void);

  extern void kprobes_inc_nmissed_count(struct kprobe *p);

  extern bool arch_within_kprobe_blacklist(unsigned long addr);

  extern int arch_populate_kprobe_blacklist(void);

  extern bool arch_kprobe_on_func_entry(unsigned long offset);
  extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);

  extern bool within_kprobe_blacklist(unsigned long addr);

  extern int kprobe_add_ksym_blacklist(unsigned long entry);
  extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);

  struct kprobe_insn_cache {
  	struct mutex mutex;

  	void *(*alloc)(void);	/* allocate insn page */
  	void (*free)(void *);	/* free insn page */

  	const char *sym;	/* symbol for insn pages */

  	struct list_head pages; /* list of kprobe_insn_page */
  	size_t insn_size;	/* size of instruction slot */
  	int nr_garbage;
  };

  #ifdef __ARCH_WANT_KPROBES_INSN_SLOT

  extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
  extern void __free_insn_slot(struct kprobe_insn_cache *c,
  			     kprobe_opcode_t *slot, int dirty);

  /* sleep-less address checking routine  */
  extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
  				unsigned long addr);

  
  #define DEFINE_INSN_CACHE_OPS(__name)					\
  extern struct kprobe_insn_cache kprobe_##__name##_slots;		\
  									\
  static inline kprobe_opcode_t *get_##__name##_slot(void)		\
  {									\
  	return __get_insn_slot(&kprobe_##__name##_slots);		\
  }									\
  									\
  static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
  {									\
  	__free_insn_slot(&kprobe_##__name##_slots, slot, dirty);	\
  }									\

  									\
  static inline bool is_kprobe_##__name##_slot(unsigned long addr)	\
  {									\
  	return __is_insn_slot_addr(&kprobe_##__name##_slots, addr);	\
  }

  #define KPROBE_INSN_PAGE_SYM		"kprobe_insn_page"
  #define KPROBE_OPTINSN_PAGE_SYM		"kprobe_optinsn_page"
  int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
  			     unsigned long *value, char *type, char *sym);

  #else /* __ARCH_WANT_KPROBES_INSN_SLOT */
  #define DEFINE_INSN_CACHE_OPS(__name)					\
  static inline bool is_kprobe_##__name##_slot(unsigned long addr)	\
  {									\
  	return 0;							\
  }
  #endif

  
  DEFINE_INSN_CACHE_OPS(insn);

  #ifdef CONFIG_OPTPROBES
  /*
   * Internal structure for direct jump optimized probe
   */
  struct optimized_kprobe {
  	struct kprobe kp;
  	struct list_head list;	/* list for optimizing queue */
  	struct arch_optimized_insn optinsn;
  };
  
  /* Architecture dependent functions for direct jump optimization */
  extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
  extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);

  extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
  					 struct kprobe *orig);

  extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);

  extern void arch_optimize_kprobes(struct list_head *oplist);

  extern void arch_unoptimize_kprobes(struct list_head *oplist,
  				    struct list_head *done_list);

  extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);

  extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
  					unsigned long addr);
  
  extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);

  DEFINE_INSN_CACHE_OPS(optinsn);

  #ifdef CONFIG_SYSCTL
  extern int sysctl_kprobes_optimization;
  extern int proc_kprobes_optimization_handler(struct ctl_table *table,

  					     int write, void *buffer,

  					     size_t *length, loff_t *ppos);
  #endif

  extern void wait_for_kprobe_optimizer(void);
  #else
  static inline void wait_for_kprobe_optimizer(void) { }

  #endif /* CONFIG_OPTPROBES */

  #ifdef CONFIG_KPROBES_ON_FTRACE

  extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,

  				  struct ftrace_ops *ops, struct pt_regs *regs);

  extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
  #endif

  int arch_check_ftrace_location(struct kprobe *p);

  /* Get the kprobe at this addr (if any) - called with preemption disabled */

  struct kprobe *get_kprobe(void *addr);

  /* kprobe_running() will just return the current_kprobe on this CPU */
  static inline struct kprobe *kprobe_running(void)
  {

  	return (__this_cpu_read(current_kprobe));

  }
  
  static inline void reset_current_kprobe(void)
  {

  	__this_cpu_write(current_kprobe, NULL);

  }
  
  static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
  {

  	return this_cpu_ptr(&kprobe_ctlblk);

  }

  kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset);

  int register_kprobe(struct kprobe *p);
  void unregister_kprobe(struct kprobe *p);

  int register_kprobes(struct kprobe **kps, int num);
  void unregister_kprobes(struct kprobe **kps, int num);

  unsigned long arch_deref_entry_point(void *);

  int register_kretprobe(struct kretprobe *rp);
  void unregister_kretprobe(struct kretprobe *rp);

  int register_kretprobes(struct kretprobe **rps, int num);
  void unregister_kretprobes(struct kretprobe **rps, int num);

  void kprobe_flush_task(struct task_struct *tk);

  void kprobe_free_init_mem(void);

  int disable_kprobe(struct kprobe *kp);
  int enable_kprobe(struct kprobe *kp);

  void dump_kprobe(struct kprobe *kp);

  void *alloc_insn_page(void);
  void free_insn_page(void *page);

  int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
  		       char *sym);
  
  int arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
  			    char *type, char *sym);

  #else /* !CONFIG_KPROBES: */

  static inline int kprobes_built_in(void)
  {
  	return 0;
  }
  static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
  {
  	return 0;
  }

  static inline struct kprobe *get_kprobe(void *addr)
  {
  	return NULL;
  }

  static inline struct kprobe *kprobe_running(void)

  {

  	return NULL;

  }
  static inline int register_kprobe(struct kprobe *p)
  {
  	return -ENOSYS;
  }

  static inline int register_kprobes(struct kprobe **kps, int num)
  {
  	return -ENOSYS;
  }

  static inline void unregister_kprobe(struct kprobe *p)
  {
  }

  static inline void unregister_kprobes(struct kprobe **kps, int num)
  {
  }

  static inline int register_kretprobe(struct kretprobe *rp)
  {
  	return -ENOSYS;
  }

  static inline int register_kretprobes(struct kretprobe **rps, int num)
  {
  	return -ENOSYS;
  }

  static inline void unregister_kretprobe(struct kretprobe *rp)
  {
  }

  static inline void unregister_kretprobes(struct kretprobe **rps, int num)
  {
  }

  static inline void kprobe_flush_task(struct task_struct *tk)
  {
  }

  static inline void kprobe_free_init_mem(void)
  {
  }

  static inline int disable_kprobe(struct kprobe *kp)
  {
  	return -ENOSYS;
  }
  static inline int enable_kprobe(struct kprobe *kp)
  {
  	return -ENOSYS;
  }

  
  static inline bool within_kprobe_blacklist(unsigned long addr)
  {
  	return true;
  }

  static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value,
  				     char *type, char *sym)
  {
  	return -ERANGE;
  }

  #endif /* CONFIG_KPROBES */

  static inline int disable_kretprobe(struct kretprobe *rp)
  {
  	return disable_kprobe(&rp->kp);
  }
  static inline int enable_kretprobe(struct kretprobe *rp)
  {
  	return enable_kprobe(&rp->kp);
  }

  #ifndef CONFIG_KPROBES
  static inline bool is_kprobe_insn_slot(unsigned long addr)
  {
  	return false;
  }
  #endif
  #ifndef CONFIG_OPTPROBES
  static inline bool is_kprobe_optinsn_slot(unsigned long addr)
  {
  	return false;
  }
  #endif

  /* Returns true if kprobes handled the fault */
  static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
  					      unsigned int trap)
  {
  	if (!kprobes_built_in())
  		return false;
  	if (user_mode(regs))
  		return false;
  	/*
  	 * To be potentially processing a kprobe fault and to be allowed
  	 * to call kprobe_running(), we have to be non-preemptible.
  	 */
  	if (preemptible())
  		return false;
  	if (!kprobe_running())
  		return false;
  	return kprobe_fault_handler(regs, trap);
  }

  #endif /* _LINUX_KPROBES_H */