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/* 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[];
#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 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 */
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