/* 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 {
struct hlist_node hlist;
struct kretprobe *rp;
kprobe_opcode_t *ret_addr;
struct task_struct *task;
void *fp;
char data[0];
};
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;
}
#ifdef CONFIG_KRETPROBES
extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs);
extern int arch_trampoline_kprobe(struct kprobe *p);
#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[];
static inline void kretprobe_assert(struct kretprobe_instance *ri,
unsigned long orig_ret_address, unsigned long trampoline_address)
{
if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
ri->rp, ri->rp->kp.addr);
BUG();
}
}
#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 show_registers(struct pt_regs *regs);
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 */
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); \
}
#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 __user *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);
void kretprobe_hash_lock(struct task_struct *tsk,
struct hlist_head **head, unsigned long *flags);
void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
/* 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 recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
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);
#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 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;
}
#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 */
