[linux-block.git] / include / linux / kprobes.h

/* SPDX-License-Identifier: GPL-2.0-or-later */
#ifndef _LINUX_KPROBES_H
#define _LINUX_KPROBES_H
/*
 *  Kernel Probes (KProbes)
 *
 * 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 <linux/objpool.h>
#include <linux/rethook.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 (*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;

	/* 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 */
#define KPROBE_FLAG_ON_FUNC_ENTRY	16 /* probe is on the function entry */

/* Has this kprobe gone ? */
static inline bool kprobe_gone(struct kprobe *p)
{
	return p->flags & KPROBE_FLAG_GONE;
}

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

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

/* Is this kprobe uses ftrace ? */
static inline bool 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_holder {
	struct kretprobe __rcu *rp;
	struct objpool_head	pool;
};

struct kretprobe {
	struct kprobe kp;
	kretprobe_handler_t handler;
	kretprobe_handler_t entry_handler;
	int maxactive;
	int nmissed;
	size_t data_size;
#ifdef CONFIG_KRETPROBE_ON_RETHOOK
	struct rethook *rh;
#else
	struct kretprobe_holder *rph;
#endif
};

#define KRETPROBE_MAX_DATA_SIZE	4096

struct kretprobe_instance {
#ifdef CONFIG_KRETPROBE_ON_RETHOOK
	struct rethook_node node;
#else
	struct rcu_head rcu;
	struct llist_node llist;
	struct kretprobe_holder *rph;
	kprobe_opcode_t *ret_addr;
	void *fp;
#endif
	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);

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

#ifdef CONFIG_KRETPROBES
/* Check whether @p is used for implementing a trampoline. */
extern int arch_trampoline_kprobe(struct kprobe *p);

#ifdef CONFIG_KRETPROBE_ON_RETHOOK
static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance *ri)
{
	/* rethook::data is non-changed field, so that you can access it freely. */
	return (struct kretprobe *)ri->node.rethook->data;
}
static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_instance *ri)
{
	return ri->node.ret_addr;
}
#else
extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
				   struct pt_regs *regs);
void arch_kretprobe_fixup_return(struct pt_regs *regs,
				 kprobe_opcode_t *correct_ret_addr);

void __kretprobe_trampoline(void);
/*
 * Since some architecture uses structured function pointer,
 * use dereference_function_descriptor() to get real function address.
 */
static nokprobe_inline void *kretprobe_trampoline_addr(void)
{
	return dereference_kernel_function_descriptor(__kretprobe_trampoline);
}

/* If the trampoline handler called from a kprobe, use this version */
unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
					     void *frame_pointer);

static nokprobe_inline
unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
					   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, frame_pointer);
	kprobe_busy_end();

	return ret;
}

static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance *ri)
{
	return rcu_dereference_check(ri->rph->rp, rcu_read_lock_any_held());
}

static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_instance *ri)
{
	return (unsigned long)ri->ret_addr;
}
#endif /* CONFIG_KRETPROBE_ON_RETHOOK */

#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 */

/* Markers of '_kprobe_blacklist' section */
extern unsigned long __start_kprobe_blacklist[];
extern unsigned long __stop_kprobe_blacklist[];

extern struct kretprobe_blackpoint kretprobe_blacklist[];

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 int 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,
					kprobe_opcode_t *addr);

extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);

DEFINE_INSN_CACHE_OPS(optinsn);

extern void wait_for_kprobe_optimizer(void);
bool optprobe_queued_unopt(struct optimized_kprobe *op);
bool kprobe_disarmed(struct kprobe *p);
#else /* !CONFIG_OPTPROBES */
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 ftrace_regs *fregs);
extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
/* Set when ftrace has been killed: kprobes on ftrace must be disabled for safety */
extern bool kprobe_ftrace_disabled __read_mostly;
extern void kprobe_ftrace_kill(void);
#else
static inline int arch_prepare_kprobe_ftrace(struct kprobe *p)
{
	return -EINVAL;
}
static inline void kprobe_ftrace_kill(void) {}
#endif /* CONFIG_KPROBES_ON_FTRACE */

/* 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);
kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset, bool *on_func_entry);

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);

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);

#if defined(CONFIG_KRETPROBE_ON_RETHOOK) || !defined(CONFIG_KRETPROBES)
#define kprobe_flush_task(tk)	do {} while (0)
#else
void kprobe_flush_task(struct task_struct *tk);
#endif

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 *alloc_optinsn_page(void);
void free_optinsn_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);

int kprobe_exceptions_notify(struct notifier_block *self,
			     unsigned long val, void *data);

#else /* !CONFIG_KPROBES: */

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;
}
#define kprobe_busy_begin()	do {} while (0)
#define kprobe_busy_end()	do {} while (0)

static inline int register_kprobe(struct kprobe *p)
{
	return -EOPNOTSUPP;
}
static inline int register_kprobes(struct kprobe **kps, int num)
{
	return -EOPNOTSUPP;
}
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 -EOPNOTSUPP;
}
static inline int register_kretprobes(struct kretprobe **rps, int num)
{
	return -EOPNOTSUPP;
}
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 void kprobe_ftrace_kill(void)
{
}
static inline int disable_kprobe(struct kprobe *kp)
{
	return -EOPNOTSUPP;
}
static inline int enable_kprobe(struct kprobe *kp)
{
	return -EOPNOTSUPP;
}

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 /* !CONFIG_KPROBES */

#ifndef CONFIG_OPTPROBES
static inline bool is_kprobe_optinsn_slot(unsigned long addr)
{
	return false;
}
#endif /* !CONFIG_OPTPROBES */

#ifdef CONFIG_KRETPROBES
#ifdef CONFIG_KRETPROBE_ON_RETHOOK
static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
{
	return is_rethook_trampoline(addr);
}

static nokprobe_inline
unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
				      struct llist_node **cur)
{
	return rethook_find_ret_addr(tsk, (unsigned long)fp, cur);
}
#else
static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
{
	return (void *)addr == kretprobe_trampoline_addr();
}

unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
				      struct llist_node **cur);
#endif
#else
static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
{
	return false;
}

static nokprobe_inline
unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
				      struct llist_node **cur)
{
	return 0;
}
#endif

/* Returns true if kprobes handled the fault */
static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
					      unsigned int trap)
{
	if (!IS_ENABLED(CONFIG_KPROBES))
		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 */
Commit	Line	Data
	1	/* SPDX-License-Identifier: GPL-2.0-or-later */
	2	#ifndef _LINUX_KPROBES_H
	3	#define _LINUX_KPROBES_H
	4	/*
	5	* Kernel Probes (KProbes)
	6	*
	7	* Copyright (C) IBM Corporation, 2002, 2004
	8	*
	9	* 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
	10	* Probes initial implementation ( includes suggestions from
	11	* Rusty Russell).
	12	* 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
	13	* interface to access function arguments.
	14	* 2005-May Hien Nguyen <hien@us.ibm.com> and Jim Keniston
	15	* <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
	16	* <prasanna@in.ibm.com> added function-return probes.
	17	*/
	18	#include <linux/compiler.h>
	19	#include <linux/linkage.h>
	20	#include <linux/list.h>
	21	#include <linux/notifier.h>
	22	#include <linux/smp.h>
	23	#include <linux/bug.h>
	24	#include <linux/percpu.h>
	25	#include <linux/spinlock.h>
	26	#include <linux/rcupdate.h>
	27	#include <linux/mutex.h>
	28	#include <linux/ftrace.h>
	29	#include <linux/objpool.h>
	30	#include <linux/rethook.h>
	31	#include <asm/kprobes.h>
	32
	33	#ifdef CONFIG_KPROBES
	34
	35	/* kprobe_status settings */
	36	#define KPROBE_HIT_ACTIVE 0x00000001
	37	#define KPROBE_HIT_SS 0x00000002
	38	#define KPROBE_REENTER 0x00000004
	39	#define KPROBE_HIT_SSDONE 0x00000008
	40
	41	#else /* !CONFIG_KPROBES */
	42	#include <asm-generic/kprobes.h>
	43	typedef int kprobe_opcode_t;
	44	struct arch_specific_insn {
	45	int dummy;
	46	};
	47	#endif /* CONFIG_KPROBES */
	48
	49	struct kprobe;
	50	struct pt_regs;
	51	struct kretprobe;
	52	struct kretprobe_instance;
	53	typedef int (kprobe_pre_handler_t) (struct kprobe , struct pt_regs *);
	54	typedef void (kprobe_post_handler_t) (struct kprobe , struct pt_regs *,
	55	unsigned long flags);
	56	typedef int (kretprobe_handler_t) (struct kretprobe_instance ,
	57	struct pt_regs *);
	58
	59	struct kprobe {
	60	struct hlist_node hlist;
	61
	62	/* list of kprobes for multi-handler support */
	63	struct list_head list;
	64
	65	/count the number of times this probe was temporarily disarmed /
	66	unsigned long nmissed;
	67
	68	/* location of the probe point */
	69	kprobe_opcode_t *addr;
	70
	71	/* Allow user to indicate symbol name of the probe point */
	72	const char *symbol_name;
	73
	74	/* Offset into the symbol */
	75	unsigned int offset;
	76
	77	/* Called before addr is executed. */
	78	kprobe_pre_handler_t pre_handler;
	79
	80	/* Called after addr is executed, unless... */
	81	kprobe_post_handler_t post_handler;
	82
	83	/* Saved opcode (which has been replaced with breakpoint) */
	84	kprobe_opcode_t opcode;
	85
	86	/* copy of the original instruction */
	87	struct arch_specific_insn ainsn;
	88
	89	/*
	90	* Indicates various status flags.
	91	* Protected by kprobe_mutex after this kprobe is registered.
	92	*/
	93	u32 flags;
	94	};
	95
	96	/* Kprobe status flags */
	97	#define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
	98	#define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
	99	#define KPROBE_FLAG_OPTIMIZED 4 /*
	100	* probe is really optimized.
	101	* NOTE:
	102	* this flag is only for optimized_kprobe.
	103	*/
	104	#define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */
	105	#define KPROBE_FLAG_ON_FUNC_ENTRY 16 /* probe is on the function entry */
	106
	107	/* Has this kprobe gone ? */
	108	static inline bool kprobe_gone(struct kprobe *p)
	109	{
	110	return p->flags & KPROBE_FLAG_GONE;
	111	}
	112
	113	/* Is this kprobe disabled ? */
	114	static inline bool kprobe_disabled(struct kprobe *p)
	115	{
	116	return p->flags & (KPROBE_FLAG_DISABLED \| KPROBE_FLAG_GONE);
	117	}
	118
	119	/* Is this kprobe really running optimized path ? */
	120	static inline bool kprobe_optimized(struct kprobe *p)
	121	{
	122	return p->flags & KPROBE_FLAG_OPTIMIZED;
	123	}
	124
	125	/* Is this kprobe uses ftrace ? */
	126	static inline bool kprobe_ftrace(struct kprobe *p)
	127	{
	128	return p->flags & KPROBE_FLAG_FTRACE;
	129	}
	130
	131	/*
	132	* Function-return probe -
	133	* Note:
	134	* User needs to provide a handler function, and initialize maxactive.
	135	* maxactive - The maximum number of instances of the probed function that
	136	* can be active concurrently.
	137	* nmissed - tracks the number of times the probed function's return was
	138	* ignored, due to maxactive being too low.
	139	*
	140	*/
	141	struct kretprobe_holder {
	142	struct kretprobe __rcu *rp;
	143	struct objpool_head pool;
	144	};
	145
	146	struct kretprobe {
	147	struct kprobe kp;
	148	kretprobe_handler_t handler;
	149	kretprobe_handler_t entry_handler;
	150	int maxactive;
	151	int nmissed;
	152	size_t data_size;
	153	#ifdef CONFIG_KRETPROBE_ON_RETHOOK
	154	struct rethook *rh;
	155	#else
	156	struct kretprobe_holder *rph;
	157	#endif
	158	};
	159
	160	#define KRETPROBE_MAX_DATA_SIZE 4096
	161
	162	struct kretprobe_instance {
	163	#ifdef CONFIG_KRETPROBE_ON_RETHOOK
	164	struct rethook_node node;
	165	#else
	166	struct rcu_head rcu;
	167	struct llist_node llist;
	168	struct kretprobe_holder *rph;
	169	kprobe_opcode_t *ret_addr;
	170	void *fp;
	171	#endif
	172	char data[];
	173	};
	174
	175	struct kretprobe_blackpoint {
	176	const char *name;
	177	void *addr;
	178	};
	179
	180	struct kprobe_blacklist_entry {
	181	struct list_head list;
	182	unsigned long start_addr;
	183	unsigned long end_addr;
	184	};
	185
	186	#ifdef CONFIG_KPROBES
	187	DECLARE_PER_CPU(struct kprobe *, current_kprobe);
	188	DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
	189
	190	extern void kprobe_busy_begin(void);
	191	extern void kprobe_busy_end(void);
	192
	193	#ifdef CONFIG_KRETPROBES
	194	/* Check whether @p is used for implementing a trampoline. */
	195	extern int arch_trampoline_kprobe(struct kprobe *p);
	196
	197	#ifdef CONFIG_KRETPROBE_ON_RETHOOK
	198	static nokprobe_inline struct kretprobe get_kretprobe(struct kretprobe_instance ri)
	199	{
	200	/* rethook::data is non-changed field, so that you can access it freely. */
	201	return (struct kretprobe *)ri->node.rethook->data;
	202	}
	203	static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_instance *ri)
	204	{
	205	return ri->node.ret_addr;
	206	}
	207	#else
	208	extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
	209	struct pt_regs *regs);
	210	void arch_kretprobe_fixup_return(struct pt_regs *regs,
	211	kprobe_opcode_t *correct_ret_addr);
	212
	213	void __kretprobe_trampoline(void);
	214	/*
	215	* Since some architecture uses structured function pointer,
	216	* use dereference_function_descriptor() to get real function address.
	217	*/
	218	static nokprobe_inline void *kretprobe_trampoline_addr(void)
	219	{
	220	return dereference_kernel_function_descriptor(__kretprobe_trampoline);
	221	}
	222
	223	/* If the trampoline handler called from a kprobe, use this version */
	224	unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
	225	void *frame_pointer);
	226
	227	static nokprobe_inline
	228	unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
	229	void *frame_pointer)
	230	{
	231	unsigned long ret;
	232	/*
	233	* Set a dummy kprobe for avoiding kretprobe recursion.
	234	* Since kretprobe never runs in kprobe handler, no kprobe must
	235	* be running at this point.
	236	*/
	237	kprobe_busy_begin();
	238	ret = __kretprobe_trampoline_handler(regs, frame_pointer);
	239	kprobe_busy_end();
	240
	241	return ret;
	242	}
	243
	244	static nokprobe_inline struct kretprobe get_kretprobe(struct kretprobe_instance ri)
	245	{
	246	return rcu_dereference_check(ri->rph->rp, rcu_read_lock_any_held());
	247	}
	248
	249	static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_instance *ri)
	250	{
	251	return (unsigned long)ri->ret_addr;
	252	}
	253	#endif /* CONFIG_KRETPROBE_ON_RETHOOK */
	254
	255	#else /* !CONFIG_KRETPROBES */
	256	static inline void arch_prepare_kretprobe(struct kretprobe *rp,
	257	struct pt_regs *regs)
	258	{
	259	}
	260	static inline int arch_trampoline_kprobe(struct kprobe *p)
	261	{
	262	return 0;
	263	}
	264	#endif /* CONFIG_KRETPROBES */
	265
	266	/* Markers of '_kprobe_blacklist' section */
	267	extern unsigned long __start_kprobe_blacklist[];
	268	extern unsigned long __stop_kprobe_blacklist[];
	269
	270	extern struct kretprobe_blackpoint kretprobe_blacklist[];
	271
	272	extern int arch_prepare_kprobe(struct kprobe *p);
	273	extern void arch_arm_kprobe(struct kprobe *p);
	274	extern void arch_disarm_kprobe(struct kprobe *p);
	275	extern int arch_init_kprobes(void);
	276	extern void kprobes_inc_nmissed_count(struct kprobe *p);
	277	extern bool arch_within_kprobe_blacklist(unsigned long addr);
	278	extern int arch_populate_kprobe_blacklist(void);
	279	extern int kprobe_on_func_entry(kprobe_opcode_t addr, const char sym, unsigned long offset);
	280
	281	extern bool within_kprobe_blacklist(unsigned long addr);
	282	extern int kprobe_add_ksym_blacklist(unsigned long entry);
	283	extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);
	284
	285	struct kprobe_insn_cache {
	286	struct mutex mutex;
	287	void (alloc)(void); /* allocate insn page */
	288	void (free)(void ); /* free insn page */
	289	const char sym; / symbol for insn pages */
	290	struct list_head pages; /* list of kprobe_insn_page */
	291	size_t insn_size; /* size of instruction slot */
	292	int nr_garbage;
	293	};
	294
	295	#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
	296	extern kprobe_opcode_t __get_insn_slot(struct kprobe_insn_cache c);
	297	extern void __free_insn_slot(struct kprobe_insn_cache *c,
	298	kprobe_opcode_t *slot, int dirty);
	299	/* sleep-less address checking routine */
	300	extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
	301	unsigned long addr);
	302
	303	#define DEFINE_INSN_CACHE_OPS(__name) \
	304	extern struct kprobe_insn_cache kprobe_##__name##_slots; \
	305	\
	306	static inline kprobe_opcode_t *get_##__name##_slot(void) \
	307	{ \
	308	return __get_insn_slot(&kprobe_##__name##_slots); \
	309	} \
	310	\
	311	static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
	312	{ \
	313	__free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \
	314	} \
	315	\
	316	static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
	317	{ \
	318	return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \
	319	}
	320	#define KPROBE_INSN_PAGE_SYM "kprobe_insn_page"
	321	#define KPROBE_OPTINSN_PAGE_SYM "kprobe_optinsn_page"
	322	int kprobe_cache_get_kallsym(struct kprobe_insn_cache c, unsigned int symnum,
	323	unsigned long value, char type, char *sym);
	324	#else /* !__ARCH_WANT_KPROBES_INSN_SLOT */
	325	#define DEFINE_INSN_CACHE_OPS(__name) \
	326	static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
	327	{ \
	328	return 0; \
	329	}
	330	#endif
	331
	332	DEFINE_INSN_CACHE_OPS(insn);
	333
	334	#ifdef CONFIG_OPTPROBES
	335	/*
	336	* Internal structure for direct jump optimized probe
	337	*/
	338	struct optimized_kprobe {
	339	struct kprobe kp;
	340	struct list_head list; /* list for optimizing queue */
	341	struct arch_optimized_insn optinsn;
	342	};
	343
	344	/* Architecture dependent functions for direct jump optimization */
	345	extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
	346	extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
	347	extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
	348	struct kprobe *orig);
	349	extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
	350	extern void arch_optimize_kprobes(struct list_head *oplist);
	351	extern void arch_unoptimize_kprobes(struct list_head *oplist,
	352	struct list_head *done_list);
	353	extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
	354	extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
	355	kprobe_opcode_t *addr);
	356
	357	extern void opt_pre_handler(struct kprobe p, struct pt_regs regs);
	358
	359	DEFINE_INSN_CACHE_OPS(optinsn);
	360
	361	extern void wait_for_kprobe_optimizer(void);
	362	bool optprobe_queued_unopt(struct optimized_kprobe *op);
	363	bool kprobe_disarmed(struct kprobe *p);
	364	#else /* !CONFIG_OPTPROBES */
	365	static inline void wait_for_kprobe_optimizer(void) { }
	366	#endif /* CONFIG_OPTPROBES */
	367
	368	#ifdef CONFIG_KPROBES_ON_FTRACE
	369	extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
	370	struct ftrace_ops ops, struct ftrace_regs fregs);
	371	extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
	372	/* Set when ftrace has been killed: kprobes on ftrace must be disabled for safety */
	373	extern bool kprobe_ftrace_disabled __read_mostly;
	374	extern void kprobe_ftrace_kill(void);
	375	#else
	376	static inline int arch_prepare_kprobe_ftrace(struct kprobe *p)
	377	{
	378	return -EINVAL;
	379	}
	380	static inline void kprobe_ftrace_kill(void) {}
	381	#endif /* CONFIG_KPROBES_ON_FTRACE */
	382
	383	/* Get the kprobe at this addr (if any) - called with preemption disabled */
	384	struct kprobe get_kprobe(void addr);
	385
	386	/* kprobe_running() will just return the current_kprobe on this CPU */
	387	static inline struct kprobe *kprobe_running(void)
	388	{
	389	return __this_cpu_read(current_kprobe);
	390	}
	391
	392	static inline void reset_current_kprobe(void)
	393	{
	394	__this_cpu_write(current_kprobe, NULL);
	395	}
	396
	397	static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
	398	{
	399	return this_cpu_ptr(&kprobe_ctlblk);
	400	}
	401
	402	kprobe_opcode_t kprobe_lookup_name(const char name, unsigned int offset);
	403	kprobe_opcode_t arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset, bool on_func_entry);
	404
	405	int register_kprobe(struct kprobe *p);
	406	void unregister_kprobe(struct kprobe *p);
	407	int register_kprobes(struct kprobe **kps, int num);
	408	void unregister_kprobes(struct kprobe **kps, int num);
	409
	410	int register_kretprobe(struct kretprobe *rp);
	411	void unregister_kretprobe(struct kretprobe *rp);
	412	int register_kretprobes(struct kretprobe **rps, int num);
	413	void unregister_kretprobes(struct kretprobe **rps, int num);
	414
	415	#if defined(CONFIG_KRETPROBE_ON_RETHOOK) \|\| !defined(CONFIG_KRETPROBES)
	416	#define kprobe_flush_task(tk) do {} while (0)
	417	#else
	418	void kprobe_flush_task(struct task_struct *tk);
	419	#endif
	420
	421	void kprobe_free_init_mem(void);
	422
	423	int disable_kprobe(struct kprobe *kp);
	424	int enable_kprobe(struct kprobe *kp);
	425
	426	void dump_kprobe(struct kprobe *kp);
	427
	428	void *alloc_insn_page(void);
	429
	430	void *alloc_optinsn_page(void);
	431	void free_optinsn_page(void *page);
	432
	433	int kprobe_get_kallsym(unsigned int symnum, unsigned long value, char type,
	434	char *sym);
	435
	436	int arch_kprobe_get_kallsym(unsigned int symnum, unsigned long value,
	437	char type, char sym);
	438
	439	int kprobe_exceptions_notify(struct notifier_block *self,
	440	unsigned long val, void *data);
	441
	442	#else /* !CONFIG_KPROBES: */
	443
	444	static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
	445	{
	446	return 0;
	447	}
	448	static inline struct kprobe get_kprobe(void addr)
	449	{
	450	return NULL;
	451	}
	452	static inline struct kprobe *kprobe_running(void)
	453	{
	454	return NULL;
	455	}
	456	#define kprobe_busy_begin() do {} while (0)
	457	#define kprobe_busy_end() do {} while (0)
	458
	459	static inline int register_kprobe(struct kprobe *p)
	460	{
	461	return -EOPNOTSUPP;
	462	}
	463	static inline int register_kprobes(struct kprobe **kps, int num)
	464	{
	465	return -EOPNOTSUPP;
	466	}
	467	static inline void unregister_kprobe(struct kprobe *p)
	468	{
	469	}
	470	static inline void unregister_kprobes(struct kprobe **kps, int num)
	471	{
	472	}
	473	static inline int register_kretprobe(struct kretprobe *rp)
	474	{
	475	return -EOPNOTSUPP;
	476	}
	477	static inline int register_kretprobes(struct kretprobe **rps, int num)
	478	{
	479	return -EOPNOTSUPP;
	480	}
	481	static inline void unregister_kretprobe(struct kretprobe *rp)
	482	{
	483	}
	484	static inline void unregister_kretprobes(struct kretprobe **rps, int num)
	485	{
	486	}
	487	static inline void kprobe_flush_task(struct task_struct *tk)
	488	{
	489	}
	490	static inline void kprobe_free_init_mem(void)
	491	{
	492	}
	493	static inline void kprobe_ftrace_kill(void)
	494	{
	495	}
	496	static inline int disable_kprobe(struct kprobe *kp)
	497	{
	498	return -EOPNOTSUPP;
	499	}
	500	static inline int enable_kprobe(struct kprobe *kp)
	501	{
	502	return -EOPNOTSUPP;
	503	}
	504
	505	static inline bool within_kprobe_blacklist(unsigned long addr)
	506	{
	507	return true;
	508	}
	509	static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value,
	510	char type, char sym)
	511	{
	512	return -ERANGE;
	513	}
	514	#endif /* CONFIG_KPROBES */
	515
	516	static inline int disable_kretprobe(struct kretprobe *rp)
	517	{
	518	return disable_kprobe(&rp->kp);
	519	}
	520	static inline int enable_kretprobe(struct kretprobe *rp)
	521	{
	522	return enable_kprobe(&rp->kp);
	523	}
	524
	525	#ifndef CONFIG_KPROBES
	526	static inline bool is_kprobe_insn_slot(unsigned long addr)
	527	{
	528	return false;
	529	}
	530	#endif /* !CONFIG_KPROBES */
	531
	532	#ifndef CONFIG_OPTPROBES
	533	static inline bool is_kprobe_optinsn_slot(unsigned long addr)
	534	{
	535	return false;
	536	}
	537	#endif /* !CONFIG_OPTPROBES */
	538
	539	#ifdef CONFIG_KRETPROBES
	540	#ifdef CONFIG_KRETPROBE_ON_RETHOOK
	541	static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
	542	{
	543	return is_rethook_trampoline(addr);
	544	}
	545
	546	static nokprobe_inline
	547	unsigned long kretprobe_find_ret_addr(struct task_struct tsk, void fp,
	548	struct llist_node **cur)
	549	{
	550	return rethook_find_ret_addr(tsk, (unsigned long)fp, cur);
	551	}
	552	#else
	553	static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
	554	{
	555	return (void *)addr == kretprobe_trampoline_addr();
	556	}
	557
	558	unsigned long kretprobe_find_ret_addr(struct task_struct tsk, void fp,
	559	struct llist_node **cur);
	560	#endif
	561	#else
	562	static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
	563	{
	564	return false;
	565	}
	566
	567	static nokprobe_inline
	568	unsigned long kretprobe_find_ret_addr(struct task_struct tsk, void fp,
	569	struct llist_node **cur)
	570	{
	571	return 0;
	572	}
	573	#endif
	574
	575	/* Returns true if kprobes handled the fault */
	576	static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
	577	unsigned int trap)
	578	{
	579	if (!IS_ENABLED(CONFIG_KPROBES))
	580	return false;
	581	if (user_mode(regs))
	582	return false;
	583	/*
	584	* To be potentially processing a kprobe fault and to be allowed
	585	* to call kprobe_running(), we have to be non-preemptible.
	586	*/
	587	if (preemptible())
	588	return false;
	589	if (!kprobe_running())
	590	return false;
	591	return kprobe_fault_handler(regs, trap);
	592	}
	593
	594	#endif /* _LINUX_KPROBES_H */