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/* 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 <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 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_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); /* * For #ifdef avoidance: */ static inline int kprobes_built_in(void) { return 1; } extern void kprobe_busy_begin(void); extern void kprobe_busy_end(void); #ifdef CONFIG_KRETPROBES extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs); extern int arch_trampoline_kprobe(struct kprobe *p); /* If the trampoline handler called from a kprobe, use this version */ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, void *trampoline_address, void *frame_pointer); static nokprobe_inline unsigned long kretprobe_trampoline_handler(struct pt_regs *regs, void *trampoline_address, void *frame_pointer) { unsigned long ret; /* * Set a dummy kprobe for avoiding kretprobe recursion. * Since kretprobe never runs in kprobe handler, no kprobe must * be running at this point. */ kprobe_busy_begin(); ret = __kretprobe_trampoline_handler(regs, trampoline_address, frame_pointer); kprobe_busy_end(); return ret; } 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 */ extern struct kretprobe_blackpoint kretprobe_blacklist[]; #ifdef CONFIG_KPROBES_SANITY_TEST extern int init_test_probes(void); #else static inline int init_test_probes(void) { return 0; } #endif /* CONFIG_KPROBES_SANITY_TEST */ extern int arch_prepare_kprobe(struct kprobe *p); extern void arch_arm_kprobe(struct kprobe *p); extern void arch_disarm_kprobe(struct kprobe *p); extern int arch_init_kprobes(void); extern void kprobes_inc_nmissed_count(struct kprobe *p); extern bool arch_within_kprobe_blacklist(unsigned long addr); extern int arch_populate_kprobe_blacklist(void); extern bool arch_kprobe_on_func_entry(unsigned long offset); extern 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, unsigned long addr); extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs); DEFINE_INSN_CACHE_OPS(optinsn); #ifdef CONFIG_SYSCTL extern int sysctl_kprobes_optimization; extern int proc_kprobes_optimization_handler(struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos); #endif extern void wait_for_kprobe_optimizer(void); #else static inline void wait_for_kprobe_optimizer(void) { } #endif /* CONFIG_OPTPROBES */ #ifdef CONFIG_KPROBES_ON_FTRACE extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ops, struct ftrace_regs *fregs); extern int arch_prepare_kprobe_ftrace(struct kprobe *p); #endif int arch_check_ftrace_location(struct kprobe *p); /* Get the kprobe at this addr (if any) - called with preemption disabled */ struct kprobe *get_kprobe(void *addr); /* kprobe_running() will just return the current_kprobe on this CPU */ static inline struct kprobe *kprobe_running(void) { return (__this_cpu_read(current_kprobe)); } static inline void reset_current_kprobe(void) { __this_cpu_write(current_kprobe, NULL); } static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void) { return this_cpu_ptr(&kprobe_ctlblk); } kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset); int register_kprobe(struct kprobe *p); void unregister_kprobe(struct kprobe *p); int register_kprobes(struct kprobe **kps, int num); void unregister_kprobes(struct kprobe **kps, int num); unsigned long arch_deref_entry_point(void *); int register_kretprobe(struct kretprobe *rp); void unregister_kretprobe(struct kretprobe *rp); int register_kretprobes(struct kretprobe **rps, int num); void unregister_kretprobes(struct kretprobe **rps, int num); void kprobe_flush_task(struct task_struct *tk); void kprobe_free_init_mem(void); int disable_kprobe(struct kprobe *kp); int enable_kprobe(struct kprobe *kp); void dump_kprobe(struct kprobe *kp); void *alloc_insn_page(void); void *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 kprobes_built_in(void) { return 0; } static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) { return 0; } static inline struct kprobe *get_kprobe(void *addr) { return NULL; } static inline struct kprobe *kprobe_running(void) { return NULL; } static inline int register_kprobe(struct kprobe *p) { return -ENOSYS; } static inline int register_kprobes(struct kprobe **kps, int num) { return -ENOSYS; } static inline void unregister_kprobe(struct kprobe *p) { } static inline void unregister_kprobes(struct kprobe **kps, int num) { } static inline int register_kretprobe(struct kretprobe *rp) { return -ENOSYS; } static inline int register_kretprobes(struct kretprobe **rps, int num) { return -ENOSYS; } static inline void unregister_kretprobe(struct kretprobe *rp) { } static inline void unregister_kretprobes(struct kretprobe **rps, int num) { } static inline void kprobe_flush_task(struct task_struct *tk) { } static inline void kprobe_free_init_mem(void) { } static inline int disable_kprobe(struct kprobe *kp) { return -ENOSYS; } static inline int enable_kprobe(struct kprobe *kp) { return -ENOSYS; } static inline bool within_kprobe_blacklist(unsigned long addr) { return true; } static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type, char *sym) { return -ERANGE; } #endif /* CONFIG_KPROBES */ static inline int disable_kretprobe(struct kretprobe *rp) { return disable_kprobe(&rp->kp); } static inline int enable_kretprobe(struct kretprobe *rp) { return enable_kprobe(&rp->kp); } #ifndef CONFIG_KPROBES static inline bool is_kprobe_insn_slot(unsigned long addr) { return false; } #endif #ifndef CONFIG_OPTPROBES static inline bool is_kprobe_optinsn_slot(unsigned long addr) { return false; } #endif /* Returns true if kprobes handled the fault */ static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs, unsigned int trap) { if (!kprobes_built_in()) return false; if (user_mode(regs)) return false; /* * To be potentially processing a kprobe fault and to be allowed * to call kprobe_running(), we have to be non-preemptible. */ if (preemptible()) return false; if (!kprobe_running()) return false; return kprobe_fault_handler(regs, trap); } #endif /* _LINUX_KPROBES_H */