[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/refcount.h>
#include <linux/freelist.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 */

/* 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	*rp;
	refcount_t		ref;
};

struct kretprobe {
	struct kprobe kp;
	kretprobe_handler_t handler;
	kretprobe_handler_t entry_handler;
	int maxactive;
	int nmissed;
	size_t data_size;
	struct freelist_head freelist;
	struct kretprobe_holder *rph;
};

#define KRETPROBE_MAX_DATA_SIZE	4096

struct kretprobe_instance {
	union {
		struct freelist_node freelist;
		struct rcu_head rcu;
	};
	struct llist_node llist;
	struct kretprobe_holder *rph;
	kprobe_opcode_t *ret_addr;
	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);

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);

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)
{
	RCU_LOCKDEP_WARN(!rcu_read_lock_any_held(),
		"Kretprobe is accessed from instance under preemptive context");

	return READ_ONCE(ri->rph->rp);
}

#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[];

#ifdef CONFIG_KPROBES_SANITY_TEST
extern int init_test_probes(void);
#else /* !CONFIG_KPROBES_SANITY_TEST */
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 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);

#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 /* CONFIG_SYSCTL */
extern void wait_for_kprobe_optimizer(void);
#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);
#else
static inline int arch_prepare_kprobe_ftrace(struct kprobe *p)
{
	return -EINVAL;
}
#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);
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);

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 *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);
#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;
}
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 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
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);
#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
1a59d1b8	1	/* SPDX-License-Identifier: GPL-2.0-or-later */
1da177e4 LT	2	#ifndef _LINUX_KPROBES_H
	3	#define _LINUX_KPROBES_H
	4	/*
	5	* Kernel Probes (KProbes)
1da177e4	6	*
1da177e4 LT	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.
b94cce92 HN	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.
1da177e4	17	*/
7d134b2c	18	#include <linux/compiler.h>
36dcd67a	19	#include <linux/linkage.h>
1da177e4 LT	20	#include <linux/list.h>
	21	#include <linux/notifier.h>
	22	#include <linux/smp.h>
187f1882	23	#include <linux/bug.h>
e6584523	24	#include <linux/percpu.h>
3516a460 AM	25	#include <linux/spinlock.h>
3516a460 AM	26	#include <linux/rcupdate.h>
7a7d1cf9	27	#include <linux/mutex.h>
ae6aa16f	28	#include <linux/ftrace.h>
d741bf41	29	#include <linux/refcount.h>
6e426e0f	30	#include <linux/freelist.h>
7d134b2c	31	#include <asm/kprobes.h>
b94cce92	32
00d7c05a	33	#ifdef CONFIG_KPROBES
1da177e4	34
ea32c65c PP	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
223a76b2	41	#else /* !CONFIG_KPROBES */
7d134b2c	42	#include <asm-generic/kprobes.h>
dc19835d MH	43	typedef int kprobe_opcode_t;
	44	struct arch_specific_insn {
	45	int dummy;
	46	};
dc19835d	47	#endif /* CONFIG_KPROBES */
d0aaff97	48
1da177e4 LT	49	struct kprobe;
1da177e4 LT	50	struct pt_regs;
b94cce92 HN	51	struct kretprobe;
b94cce92 HN	52	struct kretprobe_instance;
1da177e4	53	typedef int (kprobe_pre_handler_t) (struct kprobe , struct pt_regs *);
1da177e4 LT	54	typedef void (kprobe_post_handler_t) (struct kprobe , struct pt_regs *,
1da177e4 LT	55	unsigned long flags);
b94cce92 HN	56	typedef int (kretprobe_handler_t) (struct kretprobe_instance ,
	57	struct pt_regs *);
	58
1da177e4 LT	59	struct kprobe {
	60	struct hlist_node hlist;
	61
64f562c6 AM	62	/* list of kprobes for multi-handler support */
	63	struct list_head list;
	64
ea32c65c PP	65	/count the number of times this probe was temporarily disarmed /
	66	unsigned long nmissed;
	67
1da177e4 LT	68	/* location of the probe point */
	69	kprobe_opcode_t *addr;
	70
3a872d89	71	/* Allow user to indicate symbol name of the probe point */
9b3af29b	72	const char *symbol_name;
3a872d89 AM	73
	74	/* Offset into the symbol */
	75	unsigned int offset;
	76
1da177e4 LT	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
1da177e4 LT	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;
e8386a0c	88
de5bd88d MH	89	/*
	90	* Indicates various status flags.
	91	* Protected by kprobe_mutex after this kprobe is registered.
	92	*/
e8386a0c	93	u32 flags;
1da177e4 LT	94	};
1da177e4 LT	95
e8386a0c MH	96	/* Kprobe status flags */
e8386a0c MH	97	#define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
de5bd88d	98	#define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
afd66255 MH	99	#define KPROBE_FLAG_OPTIMIZED 4 /*
	100	* probe is really optimized.
	101	* NOTE:
	102	* this flag is only for optimized_kprobe.
	103	*/
ae6aa16f	104	#define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */
e8386a0c	105
de5bd88d	106	/* Has this kprobe gone ? */
29e8077a	107	static inline bool kprobe_gone(struct kprobe *p)
e8386a0c MH	108	{
	109	return p->flags & KPROBE_FLAG_GONE;
	110	}
	111
de5bd88d	112	/* Is this kprobe disabled ? */
29e8077a	113	static inline bool kprobe_disabled(struct kprobe *p)
de5bd88d MH	114	{
	115	return p->flags & (KPROBE_FLAG_DISABLED \| KPROBE_FLAG_GONE);
	116	}
afd66255 MH	117
afd66255 MH	118	/* Is this kprobe really running optimized path ? */
29e8077a	119	static inline bool kprobe_optimized(struct kprobe *p)
afd66255 MH	120	{
	121	return p->flags & KPROBE_FLAG_OPTIMIZED;
	122	}
ae6aa16f MH	123
ae6aa16f MH	124	/* Is this kprobe uses ftrace ? */
29e8077a	125	static inline bool kprobe_ftrace(struct kprobe *p)
ae6aa16f MH	126	{
	127	return p->flags & KPROBE_FLAG_FTRACE;
	128	}
	129
b94cce92 HN	130	/*
	131	* Function-return probe -
	132	* Note:
	133	* User needs to provide a handler function, and initialize maxactive.
	134	* maxactive - The maximum number of instances of the probed function that
	135	* can be active concurrently.
	136	* nmissed - tracks the number of times the probed function's return was
	137	* ignored, due to maxactive being too low.
	138	*
	139	*/
d741bf41 PZ	140	struct kretprobe_holder {
	141	struct kretprobe *rp;
	142	refcount_t ref;
	143	};
	144
b94cce92 HN	145	struct kretprobe {
	146	struct kprobe kp;
	147	kretprobe_handler_t handler;
f47cd9b5	148	kretprobe_handler_t entry_handler;
b94cce92 HN	149	int maxactive;
b94cce92 HN	150	int nmissed;
f47cd9b5	151	size_t data_size;
6e426e0f	152	struct freelist_head freelist;
d741bf41	153	struct kretprobe_holder *rph;
b94cce92 HN	154	};
b94cce92 HN	155
6bbfa441 MH	156	#define KRETPROBE_MAX_DATA_SIZE 4096
6bbfa441 MH	157
b94cce92	158	struct kretprobe_instance {
b3388178	159	union {
6e426e0f	160	struct freelist_node freelist;
b3388178 MH	161	struct rcu_head rcu;
b3388178 MH	162	};
6e426e0f	163	struct llist_node llist;
d741bf41	164	struct kretprobe_holder *rph;
802eae7c	165	kprobe_opcode_t *ret_addr;
3ff9c075	166	void *fp;
67a862a9	167	char data[];
b94cce92 HN	168	};
b94cce92 HN	169
f438d914 MH	170	struct kretprobe_blackpoint {
	171	const char *name;
	172	void *addr;
	173	};
3d8d996e	174
376e2424 MH	175	struct kprobe_blacklist_entry {
376e2424 MH	176	struct list_head list;
3d8d996e	177	unsigned long start_addr;
376e2424	178	unsigned long end_addr;
3d8d996e SD	179	};
3d8d996e SD	180
dc19835d MH	181	#ifdef CONFIG_KPROBES
	182	DECLARE_PER_CPU(struct kprobe *, current_kprobe);
	183	DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
	184
66ada2cc MH	185	extern void kprobe_busy_begin(void);
	186	extern void kprobe_busy_end(void);
	187
dc19835d MH	188	#ifdef CONFIG_KRETPROBES
	189	extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
	190	struct pt_regs *regs);
	191	extern int arch_trampoline_kprobe(struct kprobe *p);
66ada2cc	192
bf094cff MH	193	void arch_kretprobe_fixup_return(struct pt_regs *regs,
	194	kprobe_opcode_t *correct_ret_addr);
	195
adf8a61a	196	void __kretprobe_trampoline(void);
96fed8ac MH	197	/*
	198	* Since some architecture uses structured function pointer,
	199	* use dereference_function_descriptor() to get real function address.
	200	*/
	201	static nokprobe_inline void *kretprobe_trampoline_addr(void)
	202	{
adf8a61a	203	return dereference_kernel_function_descriptor(__kretprobe_trampoline);
96fed8ac MH	204	}
96fed8ac MH	205
66ada2cc MH	206	/* If the trampoline handler called from a kprobe, use this version */
66ada2cc MH	207	unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
96fed8ac	208	void *frame_pointer);
66ada2cc MH	209
	210	static nokprobe_inline
	211	unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
96fed8ac	212	void *frame_pointer)
66ada2cc MH	213	{
	214	unsigned long ret;
	215	/*
	216	* Set a dummy kprobe for avoiding kretprobe recursion.
	217	* Since kretprobe never runs in kprobe handler, no kprobe must
	218	* be running at this point.
	219	*/
	220	kprobe_busy_begin();
96fed8ac	221	ret = __kretprobe_trampoline_handler(regs, frame_pointer);
66ada2cc MH	222	kprobe_busy_end();
	223
	224	return ret;
	225	}
	226
d741bf41 PZ	227	static nokprobe_inline struct kretprobe get_kretprobe(struct kretprobe_instance ri)
	228	{
	229	RCU_LOCKDEP_WARN(!rcu_read_lock_any_held(),
	230	"Kretprobe is accessed from instance under preemptive context");
	231
	232	return READ_ONCE(ri->rph->rp);
	233	}
	234
223a76b2	235	#else /* !CONFIG_KRETPROBES */
dc19835d MH	236	static inline void arch_prepare_kretprobe(struct kretprobe *rp,
	237	struct pt_regs *regs)
	238	{
	239	}
	240	static inline int arch_trampoline_kprobe(struct kprobe *p)
	241	{
	242	return 0;
	243	}
	244	#endif /* CONFIG_KRETPROBES */
	245
223a76b2 MH	246	/* Markers of '_kprobe_blacklist' section */
	247	extern unsigned long __start_kprobe_blacklist[];
	248	extern unsigned long __stop_kprobe_blacklist[];
	249
f438d914 MH	250	extern struct kretprobe_blackpoint kretprobe_blacklist[];
f438d914 MH	251
8c1c9356 AM	252	#ifdef CONFIG_KPROBES_SANITY_TEST
8c1c9356 AM	253	extern int init_test_probes(void);
223a76b2	254	#else /* !CONFIG_KPROBES_SANITY_TEST */
8c1c9356 AM	255	static inline int init_test_probes(void)
	256	{
	257	return 0;
	258	}
	259	#endif /* CONFIG_KPROBES_SANITY_TEST */
	260
1da177e4	261	extern int arch_prepare_kprobe(struct kprobe *p);
7e1048b1 RL	262	extern void arch_arm_kprobe(struct kprobe *p);
7e1048b1 RL	263	extern void arch_disarm_kprobe(struct kprobe *p);
6772926b	264	extern int arch_init_kprobes(void);
bf8d5c52	265	extern void kprobes_inc_nmissed_count(struct kprobe *p);
be8f2743	266	extern bool arch_within_kprobe_blacklist(unsigned long addr);
fb1a59fa	267	extern int arch_populate_kprobe_blacklist(void);
659b957f	268	extern bool arch_kprobe_on_func_entry(unsigned long offset);
97c753e6	269	extern int kprobe_on_func_entry(kprobe_opcode_t addr, const char sym, unsigned long offset);
1da177e4	270
e5779e8e	271	extern bool within_kprobe_blacklist(unsigned long addr);
fb1a59fa MH	272	extern int kprobe_add_ksym_blacklist(unsigned long entry);
fb1a59fa MH	273	extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);
e5779e8e	274
c802d64a HC	275	struct kprobe_insn_cache {
c802d64a HC	276	struct mutex mutex;
af96397d HC	277	void (alloc)(void); /* allocate insn page */
af96397d HC	278	void (free)(void ); /* free insn page */
d002b8bc	279	const char sym; / symbol for insn pages */
c802d64a HC	280	struct list_head pages; /* list of kprobe_insn_page */
	281	size_t insn_size; /* size of instruction slot */
	282	int nr_garbage;
	283	};
	284
5b485629	285	#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
c802d64a HC	286	extern kprobe_opcode_t __get_insn_slot(struct kprobe_insn_cache c);
	287	extern void __free_insn_slot(struct kprobe_insn_cache *c,
	288	kprobe_opcode_t *slot, int dirty);
5b485629 MH	289	/* sleep-less address checking routine */
	290	extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
	291	unsigned long addr);
c802d64a HC	292
	293	#define DEFINE_INSN_CACHE_OPS(__name) \
	294	extern struct kprobe_insn_cache kprobe_##__name##_slots; \
	295	\
	296	static inline kprobe_opcode_t *get_##__name##_slot(void) \
	297	{ \
	298	return __get_insn_slot(&kprobe_##__name##_slots); \
	299	} \
	300	\
	301	static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
	302	{ \
	303	__free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \
	304	} \
5b485629 MH	305	\
	306	static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
	307	{ \
	308	return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \
	309	}
d002b8bc AH	310	#define KPROBE_INSN_PAGE_SYM "kprobe_insn_page"
	311	#define KPROBE_OPTINSN_PAGE_SYM "kprobe_optinsn_page"
	312	int kprobe_cache_get_kallsym(struct kprobe_insn_cache c, unsigned int symnum,
	313	unsigned long value, char type, char *sym);
223a76b2	314	#else /* !__ARCH_WANT_KPROBES_INSN_SLOT */
5b485629 MH	315	#define DEFINE_INSN_CACHE_OPS(__name) \
	316	static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
	317	{ \
	318	return 0; \
	319	}
	320	#endif
c802d64a HC	321
	322	DEFINE_INSN_CACHE_OPS(insn);
	323
afd66255 MH	324	#ifdef CONFIG_OPTPROBES
	325	/*
	326	* Internal structure for direct jump optimized probe
	327	*/
	328	struct optimized_kprobe {
	329	struct kprobe kp;
	330	struct list_head list; /* list for optimizing queue */
	331	struct arch_optimized_insn optinsn;
	332	};
	333
	334	/* Architecture dependent functions for direct jump optimization */
	335	extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
	336	extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
cbf6ab52 MH	337	extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
cbf6ab52 MH	338	struct kprobe *orig);
afd66255	339	extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
cd7ebe22	340	extern void arch_optimize_kprobes(struct list_head *oplist);
f984ba4e MH	341	extern void arch_unoptimize_kprobes(struct list_head *oplist,
f984ba4e MH	342	struct list_head *done_list);
afd66255	343	extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
afd66255	344	extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
c42421e2	345	kprobe_opcode_t *addr);
afd66255 MH	346
afd66255 MH	347	extern void opt_pre_handler(struct kprobe p, struct pt_regs regs);
b2be84df	348
c802d64a HC	349	DEFINE_INSN_CACHE_OPS(optinsn);
c802d64a HC	350
b2be84df MH	351	#ifdef CONFIG_SYSCTL
	352	extern int sysctl_kprobes_optimization;
	353	extern int proc_kprobes_optimization_handler(struct ctl_table *table,
32927393	354	int write, void *buffer,
b2be84df	355	size_t length, loff_t ppos);
223a76b2	356	#endif /* CONFIG_SYSCTL */
30e7d894	357	extern void wait_for_kprobe_optimizer(void);
223a76b2	358	#else /* !CONFIG_OPTPROBES */
30e7d894	359	static inline void wait_for_kprobe_optimizer(void) { }
afd66255	360	#endif /* CONFIG_OPTPROBES */
223a76b2	361
e7dbfe34	362	#ifdef CONFIG_KPROBES_ON_FTRACE
ae6aa16f	363	extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
d19ad077	364	struct ftrace_ops ops, struct ftrace_regs fregs);
ae6aa16f	365	extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
02afb8d6 PA	366	#else
	367	static inline int arch_prepare_kprobe_ftrace(struct kprobe *p)
	368	{
	369	return -EINVAL;
	370	}
223a76b2	371	#endif /* CONFIG_KPROBES_ON_FTRACE */
ae6aa16f	372
d217d545	373	/* Get the kprobe at this addr (if any) - called with preemption disabled */
1da177e4 LT	374	struct kprobe get_kprobe(void addr);
1da177e4 LT	375
e6584523 AM	376	/* kprobe_running() will just return the current_kprobe on this CPU */
	377	static inline struct kprobe *kprobe_running(void)
	378	{
223a76b2	379	return __this_cpu_read(current_kprobe);
e6584523 AM	380	}
	381
	382	static inline void reset_current_kprobe(void)
	383	{
b76834bc	384	__this_cpu_write(current_kprobe, NULL);
e6584523 AM	385	}
	386
	387	static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
	388	{
bdffd893	389	return this_cpu_ptr(&kprobe_ctlblk);
e6584523 AM	390	}
e6584523 AM	391
290e3070	392	kprobe_opcode_t kprobe_lookup_name(const char name, unsigned int offset);
1da177e4 LT	393	int register_kprobe(struct kprobe *p);
1da177e4 LT	394	void unregister_kprobe(struct kprobe *p);
9861668f MH	395	int register_kprobes(struct kprobe **kps, int num);
9861668f MH	396	void unregister_kprobes(struct kprobe **kps, int num);
1da177e4	397
b94cce92 HN	398	int register_kretprobe(struct kretprobe *rp);
b94cce92 HN	399	void unregister_kretprobe(struct kretprobe *rp);
4a296e07 MH	400	int register_kretprobes(struct kretprobe **rps, int num);
4a296e07 MH	401	void unregister_kretprobes(struct kretprobe **rps, int num);
b94cce92	402
b94cce92	403	void kprobe_flush_task(struct task_struct *tk);
8c1c9356	404
82d083ab MH	405	void kprobe_free_init_mem(void);
82d083ab MH	406
de5bd88d MH	407	int disable_kprobe(struct kprobe *kp);
	408	int enable_kprobe(struct kprobe *kp);
	409
24851d24 FW	410	void dump_kprobe(struct kprobe *kp);
24851d24 FW	411
ad3bc25a	412	void *alloc_insn_page(void);
ad3bc25a	413
7ee3e97e CL	414	void *alloc_optinsn_page(void);
	415	void free_optinsn_page(void *page);
	416
d002b8bc AH	417	int kprobe_get_kallsym(unsigned int symnum, unsigned long value, char type,
	418	char *sym);
	419
	420	int arch_kprobe_get_kallsym(unsigned int symnum, unsigned long value,
	421	char type, char sym);
b1801812	422	#else /* !CONFIG_KPROBES: */
00d7c05a	423
b1801812 IM	424	static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
	425	{
	426	return 0;
	427	}
785656a4 AS	428	static inline struct kprobe get_kprobe(void addr)
	429	{
	430	return NULL;
	431	}
e6584523	432	static inline struct kprobe *kprobe_running(void)
1da177e4	433	{
e6584523	434	return NULL;
1da177e4 LT	435	}
	436	static inline int register_kprobe(struct kprobe *p)
	437	{
223a76b2	438	return -EOPNOTSUPP;
1da177e4	439	}
9861668f MH	440	static inline int register_kprobes(struct kprobe **kps, int num)
9861668f MH	441	{
223a76b2	442	return -EOPNOTSUPP;
9861668f	443	}
1da177e4 LT	444	static inline void unregister_kprobe(struct kprobe *p)
	445	{
	446	}
9861668f MH	447	static inline void unregister_kprobes(struct kprobe **kps, int num)
	448	{
	449	}
b94cce92 HN	450	static inline int register_kretprobe(struct kretprobe *rp)
b94cce92 HN	451	{
223a76b2	452	return -EOPNOTSUPP;
b94cce92	453	}
4a296e07 MH	454	static inline int register_kretprobes(struct kretprobe **rps, int num)
4a296e07 MH	455	{
223a76b2	456	return -EOPNOTSUPP;
4a296e07	457	}
b94cce92 HN	458	static inline void unregister_kretprobe(struct kretprobe *rp)
	459	{
	460	}
4a296e07 MH	461	static inline void unregister_kretprobes(struct kretprobe **rps, int num)
	462	{
	463	}
b94cce92 HN	464	static inline void kprobe_flush_task(struct task_struct *tk)
	465	{
	466	}
82d083ab MH	467	static inline void kprobe_free_init_mem(void)
	468	{
	469	}
de5bd88d MH	470	static inline int disable_kprobe(struct kprobe *kp)
de5bd88d MH	471	{
223a76b2	472	return -EOPNOTSUPP;
de5bd88d MH	473	}
	474	static inline int enable_kprobe(struct kprobe *kp)
	475	{
223a76b2	476	return -EOPNOTSUPP;
de5bd88d	477	}
fab94075 BP	478
	479	static inline bool within_kprobe_blacklist(unsigned long addr)
	480	{
	481	return true;
	482	}
d002b8bc AH	483	static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value,
	484	char type, char sym)
	485	{
	486	return -ERANGE;
	487	}
b1801812	488	#endif /* CONFIG_KPROBES */
223a76b2	489
8f9b1528 MH	490	static inline int disable_kretprobe(struct kretprobe *rp)
	491	{
	492	return disable_kprobe(&rp->kp);
	493	}
	494	static inline int enable_kretprobe(struct kretprobe *rp)
	495	{
	496	return enable_kprobe(&rp->kp);
	497	}
8f9b1528	498
5b485629 MH	499	#ifndef CONFIG_KPROBES
	500	static inline bool is_kprobe_insn_slot(unsigned long addr)
	501	{
	502	return false;
	503	}
223a76b2 MH	504	#endif /* !CONFIG_KPROBES */
223a76b2 MH	505
5b485629 MH	506	#ifndef CONFIG_OPTPROBES
	507	static inline bool is_kprobe_optinsn_slot(unsigned long addr)
	508	{
	509	return false;
	510	}
223a76b2	511	#endif /* !CONFIG_OPTPROBES */
5b485629	512
03bac0df MH	513	#ifdef CONFIG_KRETPROBES
	514	static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
	515	{
	516	return (void *)addr == kretprobe_trampoline_addr();
	517	}
	518
	519	unsigned long kretprobe_find_ret_addr(struct task_struct tsk, void fp,
	520	struct llist_node **cur);
	521	#else
	522	static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
	523	{
	524	return false;
	525	}
	526
	527	static nokprobe_inline
	528	unsigned long kretprobe_find_ret_addr(struct task_struct tsk, void fp,
	529	struct llist_node **cur)
	530	{
	531	return 0;
	532	}
	533	#endif
	534
b98cca44 AK	535	/* Returns true if kprobes handled the fault */
	536	static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
	537	unsigned int trap)
	538	{
dfc05b55	539	if (!IS_ENABLED(CONFIG_KPROBES))
b98cca44 AK	540	return false;
	541	if (user_mode(regs))
	542	return false;
	543	/*
	544	* To be potentially processing a kprobe fault and to be allowed
	545	* to call kprobe_running(), we have to be non-preemptible.
	546	*/
	547	if (preemptible())
	548	return false;
	549	if (!kprobe_running())
	550	return false;
	551	return kprobe_fault_handler(regs, trap);
	552	}
	553
b1801812	554	#endif /* _LINUX_KPROBES_H */