bf8d5c52c3
When multiple probes are registered at the same address and if due to some recursion (probe getting triggered within a probe handler), we skip calling pre_handlers and just increment nmissed field. The below patch make sure it walks the list for multiple probes case. Without the below patch we get incorrect results of nmissed count for multiple probe case. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
237 lines
7.3 KiB
C
237 lines
7.3 KiB
C
#ifndef _LINUX_KPROBES_H
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#define _LINUX_KPROBES_H
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/*
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* Kernel Probes (KProbes)
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* include/linux/kprobes.h
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright (C) IBM Corporation, 2002, 2004
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*
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* 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
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* Probes initial implementation ( includes suggestions from
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* Rusty Russell).
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* 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
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* interface to access function arguments.
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* 2005-May Hien Nguyen <hien@us.ibm.com> and Jim Keniston
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* <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
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* <prasanna@in.ibm.com> added function-return probes.
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*/
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#include <linux/config.h>
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#include <linux/list.h>
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#include <linux/notifier.h>
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#include <linux/smp.h>
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#include <linux/percpu.h>
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#include <linux/spinlock.h>
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#include <linux/rcupdate.h>
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#ifdef CONFIG_KPROBES
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#include <asm/kprobes.h>
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/* kprobe_status settings */
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#define KPROBE_HIT_ACTIVE 0x00000001
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#define KPROBE_HIT_SS 0x00000002
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#define KPROBE_REENTER 0x00000004
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#define KPROBE_HIT_SSDONE 0x00000008
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/* Attach to insert probes on any functions which should be ignored*/
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#define __kprobes __attribute__((__section__(".kprobes.text")))
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struct kprobe;
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struct pt_regs;
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struct kretprobe;
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struct kretprobe_instance;
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typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
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typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
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typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
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unsigned long flags);
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typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
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int trapnr);
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typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
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struct pt_regs *);
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struct kprobe {
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struct hlist_node hlist;
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/* list of kprobes for multi-handler support */
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struct list_head list;
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/*count the number of times this probe was temporarily disarmed */
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unsigned long nmissed;
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/* location of the probe point */
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kprobe_opcode_t *addr;
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/* Called before addr is executed. */
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kprobe_pre_handler_t pre_handler;
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/* Called after addr is executed, unless... */
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kprobe_post_handler_t post_handler;
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/* ... called if executing addr causes a fault (eg. page fault).
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* Return 1 if it handled fault, otherwise kernel will see it. */
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kprobe_fault_handler_t fault_handler;
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/* ... called if breakpoint trap occurs in probe handler.
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* Return 1 if it handled break, otherwise kernel will see it. */
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kprobe_break_handler_t break_handler;
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/* Saved opcode (which has been replaced with breakpoint) */
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kprobe_opcode_t opcode;
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/* copy of the original instruction */
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struct arch_specific_insn ainsn;
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};
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/*
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* Special probe type that uses setjmp-longjmp type tricks to resume
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* execution at a specified entry with a matching prototype corresponding
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* to the probed function - a trick to enable arguments to become
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* accessible seamlessly by probe handling logic.
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* Note:
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* Because of the way compilers allocate stack space for local variables
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* etc upfront, regardless of sub-scopes within a function, this mirroring
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* principle currently works only for probes placed on function entry points.
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*/
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struct jprobe {
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struct kprobe kp;
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kprobe_opcode_t *entry; /* probe handling code to jump to */
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};
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DECLARE_PER_CPU(struct kprobe *, current_kprobe);
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DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
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#ifdef ARCH_SUPPORTS_KRETPROBES
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extern void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs);
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#else /* ARCH_SUPPORTS_KRETPROBES */
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static inline void arch_prepare_kretprobe(struct kretprobe *rp,
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struct pt_regs *regs)
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{
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}
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#endif /* ARCH_SUPPORTS_KRETPROBES */
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/*
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* Function-return probe -
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* Note:
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* User needs to provide a handler function, and initialize maxactive.
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* maxactive - The maximum number of instances of the probed function that
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* can be active concurrently.
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* nmissed - tracks the number of times the probed function's return was
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* ignored, due to maxactive being too low.
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*
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*/
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struct kretprobe {
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struct kprobe kp;
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kretprobe_handler_t handler;
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int maxactive;
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int nmissed;
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struct hlist_head free_instances;
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struct hlist_head used_instances;
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};
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struct kretprobe_instance {
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struct hlist_node uflist; /* either on free list or used list */
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struct hlist_node hlist;
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struct kretprobe *rp;
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kprobe_opcode_t *ret_addr;
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struct task_struct *task;
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};
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extern spinlock_t kretprobe_lock;
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extern int arch_prepare_kprobe(struct kprobe *p);
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extern void arch_copy_kprobe(struct kprobe *p);
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extern void arch_arm_kprobe(struct kprobe *p);
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extern void arch_disarm_kprobe(struct kprobe *p);
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extern void arch_remove_kprobe(struct kprobe *p);
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extern int arch_init_kprobes(void);
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extern void show_registers(struct pt_regs *regs);
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extern kprobe_opcode_t *get_insn_slot(void);
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extern void free_insn_slot(kprobe_opcode_t *slot);
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extern void kprobes_inc_nmissed_count(struct kprobe *p);
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/* Get the kprobe at this addr (if any) - called with preemption disabled */
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struct kprobe *get_kprobe(void *addr);
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struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
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/* kprobe_running() will just return the current_kprobe on this CPU */
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static inline struct kprobe *kprobe_running(void)
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{
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return (__get_cpu_var(current_kprobe));
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}
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static inline void reset_current_kprobe(void)
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{
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__get_cpu_var(current_kprobe) = NULL;
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}
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static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
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{
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return (&__get_cpu_var(kprobe_ctlblk));
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}
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int register_kprobe(struct kprobe *p);
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void unregister_kprobe(struct kprobe *p);
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int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
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int longjmp_break_handler(struct kprobe *, struct pt_regs *);
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int register_jprobe(struct jprobe *p);
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void unregister_jprobe(struct jprobe *p);
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void jprobe_return(void);
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int register_kretprobe(struct kretprobe *rp);
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void unregister_kretprobe(struct kretprobe *rp);
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struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp);
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void add_rp_inst(struct kretprobe_instance *ri);
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void kprobe_flush_task(struct task_struct *tk);
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void recycle_rp_inst(struct kretprobe_instance *ri);
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#else /* CONFIG_KPROBES */
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#define __kprobes /**/
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struct jprobe;
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struct kretprobe;
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static inline struct kprobe *kprobe_running(void)
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{
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return NULL;
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}
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static inline int register_kprobe(struct kprobe *p)
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{
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return -ENOSYS;
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}
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static inline void unregister_kprobe(struct kprobe *p)
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{
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}
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static inline int register_jprobe(struct jprobe *p)
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{
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return -ENOSYS;
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}
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static inline void unregister_jprobe(struct jprobe *p)
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{
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}
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static inline void jprobe_return(void)
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{
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}
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static inline int register_kretprobe(struct kretprobe *rp)
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{
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return -ENOSYS;
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}
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static inline void unregister_kretprobe(struct kretprobe *rp)
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{
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}
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static inline void kprobe_flush_task(struct task_struct *tk)
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{
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}
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#endif /* CONFIG_KPROBES */
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#endif /* _LINUX_KPROBES_H */
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