diff options
Diffstat (limited to 'include/linux/uprobes.h')
| -rw-r--r-- | include/linux/uprobes.h | 261 |
1 files changed, 192 insertions, 69 deletions
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 06f28beed7c2..ee3d36eda45d 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -1,64 +1,70 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ #ifndef _LINUX_UPROBES_H #define _LINUX_UPROBES_H /* * User-space Probes (UProbes) * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. - * * Copyright (C) IBM Corporation, 2008-2012 * Authors: * Srikar Dronamraju * Jim Keniston - * Copyright (C) 2011-2012 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> + * Copyright (C) 2011-2012 Red Hat, Inc., Peter Zijlstra */ #include <linux/errno.h> #include <linux/rbtree.h> +#include <linux/types.h> +#include <linux/wait.h> +#include <linux/timer.h> +#include <linux/seqlock.h> +#include <linux/mutex.h> +struct uprobe; struct vm_area_struct; struct mm_struct; struct inode; +struct notifier_block; +struct page; -#ifdef CONFIG_ARCH_SUPPORTS_UPROBES -# include <asm/uprobes.h> -#endif - +/* + * Allowed return values from uprobe consumer's handler callback + * with following meaning: + * + * UPROBE_HANDLER_REMOVE + * - Remove the uprobe breakpoint from current->mm. + * UPROBE_HANDLER_IGNORE + * - Ignore ret_handler callback for this consumer. + */ #define UPROBE_HANDLER_REMOVE 1 -#define UPROBE_HANDLER_MASK 1 +#define UPROBE_HANDLER_IGNORE 2 #define MAX_URETPROBE_DEPTH 64 -enum uprobe_filter_ctx { - UPROBE_FILTER_REGISTER, - UPROBE_FILTER_UNREGISTER, - UPROBE_FILTER_MMAP, -}; +#define UPROBE_NO_TRAMPOLINE_VADDR (~0UL) struct uprobe_consumer { - int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs); + /* + * handler() can return UPROBE_HANDLER_REMOVE to signal the need to + * unregister uprobe for current process. If UPROBE_HANDLER_REMOVE is + * returned, filter() callback has to be implemented as well and it + * should return false to "confirm" the decision to uninstall uprobe + * for the current process. If filter() is omitted or returns true, + * UPROBE_HANDLER_REMOVE is effectively ignored. + */ + int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs, __u64 *data); int (*ret_handler)(struct uprobe_consumer *self, unsigned long func, - struct pt_regs *regs); - bool (*filter)(struct uprobe_consumer *self, - enum uprobe_filter_ctx ctx, - struct mm_struct *mm); + struct pt_regs *regs, __u64 *data); + bool (*filter)(struct uprobe_consumer *self, struct mm_struct *mm); - struct uprobe_consumer *next; + struct list_head cons_node; + + __u64 id; /* set when uprobe_consumer is registered */ }; #ifdef CONFIG_UPROBES +#include <asm/uprobes.h> + enum uprobe_task_state { UTASK_RUNNING, UTASK_SSTEP, @@ -66,80 +72,201 @@ enum uprobe_task_state { UTASK_SSTEP_TRAPPED, }; +/* The state of hybrid-lifetime uprobe inside struct return_instance */ +enum hprobe_state { + HPROBE_LEASED, /* uretprobes_srcu-protected uprobe */ + HPROBE_STABLE, /* refcounted uprobe */ + HPROBE_GONE, /* NULL uprobe, SRCU expired, refcount failed */ + HPROBE_CONSUMED, /* uprobe "consumed" by uretprobe handler */ +}; + +/* + * Hybrid lifetime uprobe. Represents a uprobe instance that could be either + * SRCU protected (with SRCU protection eventually potentially timing out), + * refcounted using uprobe->ref, or there could be no valid uprobe (NULL). + * + * hprobe's internal state is setup such that background timer thread can + * atomically "downgrade" temporarily RCU-protected uprobe into refcounted one + * (or no uprobe, if refcounting failed). + * + * *stable* pointer always point to the uprobe (or could be NULL if there is + * was no valid underlying uprobe to begin with). + * + * *leased* pointer is the key to achieving race-free atomic lifetime state + * transition and can have three possible states: + * - either the same non-NULL value as *stable*, in which case uprobe is + * SRCU-protected; + * - NULL, in which case uprobe (if there is any) is refcounted; + * - special __UPROBE_DEAD value, which represents an uprobe that was SRCU + * protected initially, but SRCU period timed out and we attempted to + * convert it to refcounted, but refcount_inc_not_zero() failed, because + * uprobe effectively went away (the last consumer unsubscribed). In this + * case it's important to know that *stable* pointer (which still has + * non-NULL uprobe pointer) shouldn't be used, because lifetime of + * underlying uprobe is not guaranteed anymore. __UPROBE_DEAD is just an + * internal marker and is handled transparently by hprobe_fetch() helper. + * + * When uprobe is SRCU-protected, we also record srcu_idx value, necessary for + * SRCU unlocking. + * + * See hprobe_expire() and hprobe_fetch() for details of race-free uprobe + * state transitioning details. It all hinges on atomic xchg() over *leaded* + * pointer. *stable* pointer, once initially set, is not modified concurrently. + */ +struct hprobe { + enum hprobe_state state; + int srcu_idx; + struct uprobe *uprobe; +}; + /* * uprobe_task: Metadata of a task while it singlesteps. */ struct uprobe_task { enum uprobe_task_state state; - struct arch_uprobe_task autask; - struct return_instance *return_instances; unsigned int depth; - struct uprobe *active_uprobe; + struct return_instance *return_instances; + struct return_instance *ri_pool; + struct timer_list ri_timer; + seqcount_t ri_seqcount; + + union { + struct { + struct arch_uprobe_task autask; + unsigned long vaddr; + }; + + struct { + struct callback_head dup_xol_work; + unsigned long dup_xol_addr; + }; + }; + + struct uprobe *active_uprobe; unsigned long xol_vaddr; - unsigned long vaddr; + bool signal_denied; + + struct arch_uprobe *auprobe; }; -/* - * On a breakpoint hit, thread contests for a slot. It frees the - * slot after singlestep. Currently a fixed number of slots are - * allocated. - */ -struct xol_area { - wait_queue_head_t wq; /* if all slots are busy */ - atomic_t slot_count; /* number of in-use slots */ - unsigned long *bitmap; /* 0 = free slot */ - struct page *page; +struct return_consumer { + __u64 cookie; + __u64 id; +}; + +struct return_instance { + struct hprobe hprobe; + unsigned long func; + unsigned long stack; /* stack pointer */ + unsigned long orig_ret_vaddr; /* original return address */ + bool chained; /* true, if instance is nested */ + int cons_cnt; /* total number of session consumers */ + + struct return_instance *next; /* keep as stack */ + struct rcu_head rcu; + /* singular pre-allocated return_consumer instance for common case */ + struct return_consumer consumer; /* - * We keep the vma's vm_start rather than a pointer to the vma - * itself. The probed process or a naughty kernel module could make - * the vma go away, and we must handle that reasonably gracefully. + * extra return_consumer instances for rare cases of multiple session consumers, + * contains (cons_cnt - 1) elements */ - unsigned long vaddr; /* Page(s) of instruction slots */ + struct return_consumer *extra_consumers; +} ____cacheline_aligned; + +enum rp_check { + RP_CHECK_CALL, + RP_CHECK_CHAIN_CALL, + RP_CHECK_RET, }; +struct xol_area; + struct uprobes_state { struct xol_area *xol_area; +#ifdef CONFIG_X86_64 + struct hlist_head head_tramps; +#endif }; -extern int __weak set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); -extern int __weak set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); -extern bool __weak is_swbp_insn(uprobe_opcode_t *insn); -extern bool __weak is_trap_insn(uprobe_opcode_t *insn); -extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); -extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool); -extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); +typedef int (*uprobe_write_verify_t)(struct page *page, unsigned long vaddr, + uprobe_opcode_t *insn, int nbytes, void *data); + +extern void __init uprobes_init(void); +extern int set_swbp(struct arch_uprobe *aup, struct vm_area_struct *vma, unsigned long vaddr); +extern int set_orig_insn(struct arch_uprobe *aup, struct vm_area_struct *vma, unsigned long vaddr); +extern bool is_swbp_insn(uprobe_opcode_t *insn); +extern bool is_trap_insn(uprobe_opcode_t *insn); +extern unsigned long uprobe_get_swbp_addr(struct pt_regs *regs); +extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs); +extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma, unsigned long vaddr, uprobe_opcode_t, + bool is_register); +extern int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma, const unsigned long opcode_vaddr, + uprobe_opcode_t *insn, int nbytes, uprobe_write_verify_t verify, bool is_register, bool do_update_ref_ctr, + void *data); +extern struct uprobe *uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc); +extern int uprobe_apply(struct uprobe *uprobe, struct uprobe_consumer *uc, bool); +extern void uprobe_unregister_nosync(struct uprobe *uprobe, struct uprobe_consumer *uc); +extern void uprobe_unregister_sync(void); extern int uprobe_mmap(struct vm_area_struct *vma); extern void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end); extern void uprobe_start_dup_mmap(void); extern void uprobe_end_dup_mmap(void); extern void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm); extern void uprobe_free_utask(struct task_struct *t); -extern void uprobe_copy_process(struct task_struct *t); -extern unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs); +extern void uprobe_copy_process(struct task_struct *t, u64 flags); extern int uprobe_post_sstep_notifier(struct pt_regs *regs); extern int uprobe_pre_sstep_notifier(struct pt_regs *regs); extern void uprobe_notify_resume(struct pt_regs *regs); extern bool uprobe_deny_signal(void); -extern bool __weak arch_uprobe_skip_sstep(struct arch_uprobe *aup, struct pt_regs *regs); +extern bool arch_uprobe_skip_sstep(struct arch_uprobe *aup, struct pt_regs *regs); extern void uprobe_clear_state(struct mm_struct *mm); +extern int arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long addr); +extern int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk); +extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data); +extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs); +extern bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx, struct pt_regs *regs); +extern bool arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs); +extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, + void *src, unsigned long len); +extern void uprobe_handle_trampoline(struct pt_regs *regs); +extern void *arch_uretprobe_trampoline(unsigned long *psize); +extern unsigned long uprobe_get_trampoline_vaddr(void); +extern void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len); +extern void arch_uprobe_clear_state(struct mm_struct *mm); +extern void arch_uprobe_init_state(struct mm_struct *mm); +extern void handle_syscall_uprobe(struct pt_regs *regs, unsigned long bp_vaddr); +extern void arch_uprobe_optimize(struct arch_uprobe *auprobe, unsigned long vaddr); #else /* !CONFIG_UPROBES */ struct uprobes_state { }; -static inline int -uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) + +static inline void uprobes_init(void) { - return -ENOSYS; +} + +#define uprobe_get_trap_addr(regs) instruction_pointer(regs) + +static inline struct uprobe * +uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc) +{ + return ERR_PTR(-ENOSYS); } static inline int -uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool add) +uprobe_apply(struct uprobe* uprobe, struct uprobe_consumer *uc, bool add) { return -ENOSYS; } static inline void -uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) +uprobe_unregister_nosync(struct uprobe *uprobe, struct uprobe_consumer *uc) +{ +} +static inline void uprobe_unregister_sync(void) { } static inline int uprobe_mmap(struct vm_area_struct *vma) @@ -167,14 +294,10 @@ static inline bool uprobe_deny_signal(void) { return false; } -static inline unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) -{ - return 0; -} static inline void uprobe_free_utask(struct task_struct *t) { } -static inline void uprobe_copy_process(struct task_struct *t) +static inline void uprobe_copy_process(struct task_struct *t, u64 flags) { } static inline void uprobe_clear_state(struct mm_struct *mm) |