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![Adrian Hunter](/assets/img/avatar_default.png)
Symbols are needed for tools to describe instruction addresses. Pages allocated for kprobe's purposes need symbols to be created for them. Add such symbols to be visible via /proc/kallsyms. Note: kprobe insn pages are not used if ftrace is configured. To see the effect of this patch, the kernel must be configured with: # CONFIG_FUNCTION_TRACER is not set CONFIG_KPROBES=y and for optimised kprobes: CONFIG_OPTPROBES=y Example on x86: # perf probe __schedule Added new event: probe:__schedule (on __schedule) # cat /proc/kallsyms | grep '\[__builtin__kprobes\]' ffffffffc00d4000 t kprobe_insn_page [__builtin__kprobes] ffffffffc00d6000 t kprobe_optinsn_page [__builtin__kprobes] Note: This patch adds "__builtin__kprobes" as a module name in /proc/kallsyms for symbols for pages allocated for kprobes' purposes, even though "__builtin__kprobes" is not a module. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lkml.kernel.org/r/20200528080058.20230-1-adrian.hunter@intel.com
495 lines
14 KiB
C
495 lines
14 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#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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* 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/compiler.h>
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#include <linux/linkage.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/bug.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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#include <linux/mutex.h>
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#include <linux/ftrace.h>
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#include <asm/kprobes.h>
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#ifdef CONFIG_KPROBES
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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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#else /* CONFIG_KPROBES */
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#include <asm-generic/kprobes.h>
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typedef int kprobe_opcode_t;
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struct arch_specific_insn {
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int dummy;
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};
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#endif /* CONFIG_KPROBES */
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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 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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/* Allow user to indicate symbol name of the probe point */
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const char *symbol_name;
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/* Offset into the symbol */
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unsigned int offset;
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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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/*
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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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*/
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kprobe_fault_handler_t fault_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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* Indicates various status flags.
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* Protected by kprobe_mutex after this kprobe is registered.
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*/
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u32 flags;
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};
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/* Kprobe status flags */
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#define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
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#define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
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#define KPROBE_FLAG_OPTIMIZED 4 /*
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* probe is really optimized.
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* NOTE:
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* this flag is only for optimized_kprobe.
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*/
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#define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */
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/* Has this kprobe gone ? */
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static inline int kprobe_gone(struct kprobe *p)
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{
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return p->flags & KPROBE_FLAG_GONE;
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}
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/* Is this kprobe disabled ? */
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static inline int kprobe_disabled(struct kprobe *p)
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{
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return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
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}
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/* Is this kprobe really running optimized path ? */
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static inline int kprobe_optimized(struct kprobe *p)
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{
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return p->flags & KPROBE_FLAG_OPTIMIZED;
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}
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/* Is this kprobe uses ftrace ? */
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static inline int kprobe_ftrace(struct kprobe *p)
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{
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return p->flags & KPROBE_FLAG_FTRACE;
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}
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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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kretprobe_handler_t entry_handler;
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int maxactive;
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int nmissed;
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size_t data_size;
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struct hlist_head free_instances;
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raw_spinlock_t lock;
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};
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struct kretprobe_instance {
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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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void *fp;
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char data[0];
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};
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struct kretprobe_blackpoint {
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const char *name;
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void *addr;
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};
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struct kprobe_blacklist_entry {
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struct list_head list;
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unsigned long start_addr;
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unsigned long end_addr;
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};
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#ifdef CONFIG_KPROBES
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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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/*
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* For #ifdef avoidance:
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*/
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static inline int kprobes_built_in(void)
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{
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return 1;
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}
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#ifdef CONFIG_KRETPROBES
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extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
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struct pt_regs *regs);
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extern int arch_trampoline_kprobe(struct kprobe *p);
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#else /* CONFIG_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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static inline int arch_trampoline_kprobe(struct kprobe *p)
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{
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return 0;
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}
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#endif /* CONFIG_KRETPROBES */
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extern struct kretprobe_blackpoint kretprobe_blacklist[];
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static inline void kretprobe_assert(struct kretprobe_instance *ri,
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unsigned long orig_ret_address, unsigned long trampoline_address)
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{
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if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
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printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
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ri->rp, ri->rp->kp.addr);
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BUG();
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}
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}
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#ifdef CONFIG_KPROBES_SANITY_TEST
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extern int init_test_probes(void);
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#else
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static inline int init_test_probes(void)
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{
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return 0;
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}
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#endif /* CONFIG_KPROBES_SANITY_TEST */
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extern int arch_prepare_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 int arch_init_kprobes(void);
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extern void show_registers(struct pt_regs *regs);
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extern void kprobes_inc_nmissed_count(struct kprobe *p);
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extern bool arch_within_kprobe_blacklist(unsigned long addr);
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extern int arch_populate_kprobe_blacklist(void);
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extern bool arch_kprobe_on_func_entry(unsigned long offset);
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extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
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extern bool within_kprobe_blacklist(unsigned long addr);
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extern int kprobe_add_ksym_blacklist(unsigned long entry);
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extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);
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struct kprobe_insn_cache {
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struct mutex mutex;
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void *(*alloc)(void); /* allocate insn page */
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void (*free)(void *); /* free insn page */
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const char *sym; /* symbol for insn pages */
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struct list_head pages; /* list of kprobe_insn_page */
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size_t insn_size; /* size of instruction slot */
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int nr_garbage;
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};
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#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
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extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
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extern void __free_insn_slot(struct kprobe_insn_cache *c,
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kprobe_opcode_t *slot, int dirty);
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/* sleep-less address checking routine */
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extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
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unsigned long addr);
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#define DEFINE_INSN_CACHE_OPS(__name) \
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extern struct kprobe_insn_cache kprobe_##__name##_slots; \
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\
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static inline kprobe_opcode_t *get_##__name##_slot(void) \
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{ \
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return __get_insn_slot(&kprobe_##__name##_slots); \
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} \
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\
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static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
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{ \
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__free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \
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} \
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\
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static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
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{ \
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return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \
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}
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#define KPROBE_INSN_PAGE_SYM "kprobe_insn_page"
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#define KPROBE_OPTINSN_PAGE_SYM "kprobe_optinsn_page"
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int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
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unsigned long *value, char *type, char *sym);
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#else /* __ARCH_WANT_KPROBES_INSN_SLOT */
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#define DEFINE_INSN_CACHE_OPS(__name) \
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static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
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{ \
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return 0; \
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}
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#endif
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DEFINE_INSN_CACHE_OPS(insn);
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#ifdef CONFIG_OPTPROBES
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/*
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* Internal structure for direct jump optimized probe
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*/
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struct optimized_kprobe {
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struct kprobe kp;
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struct list_head list; /* list for optimizing queue */
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struct arch_optimized_insn optinsn;
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};
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/* Architecture dependent functions for direct jump optimization */
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extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
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extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
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extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
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struct kprobe *orig);
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extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
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extern void arch_optimize_kprobes(struct list_head *oplist);
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extern void arch_unoptimize_kprobes(struct list_head *oplist,
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struct list_head *done_list);
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extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
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extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
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unsigned long addr);
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extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
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DEFINE_INSN_CACHE_OPS(optinsn);
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#ifdef CONFIG_SYSCTL
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extern int sysctl_kprobes_optimization;
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extern int proc_kprobes_optimization_handler(struct ctl_table *table,
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int write, void *buffer,
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size_t *length, loff_t *ppos);
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#endif
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extern void wait_for_kprobe_optimizer(void);
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#else
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static inline void wait_for_kprobe_optimizer(void) { }
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#endif /* CONFIG_OPTPROBES */
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#ifdef CONFIG_KPROBES_ON_FTRACE
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extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
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struct ftrace_ops *ops, struct pt_regs *regs);
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extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
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#endif
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int arch_check_ftrace_location(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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void kretprobe_hash_lock(struct task_struct *tsk,
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struct hlist_head **head, unsigned long *flags);
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void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
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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 (__this_cpu_read(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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__this_cpu_write(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 this_cpu_ptr(&kprobe_ctlblk);
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}
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kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset);
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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 register_kprobes(struct kprobe **kps, int num);
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void unregister_kprobes(struct kprobe **kps, int num);
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unsigned long arch_deref_entry_point(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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int register_kretprobes(struct kretprobe **rps, int num);
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void unregister_kretprobes(struct kretprobe **rps, int num);
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void kprobe_flush_task(struct task_struct *tk);
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void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
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int disable_kprobe(struct kprobe *kp);
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int enable_kprobe(struct kprobe *kp);
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void dump_kprobe(struct kprobe *kp);
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void *alloc_insn_page(void);
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void free_insn_page(void *page);
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int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
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char *sym);
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int arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
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char *type, char *sym);
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#else /* !CONFIG_KPROBES: */
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static inline int kprobes_built_in(void)
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{
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return 0;
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}
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static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
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{
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return 0;
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}
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static inline struct kprobe *get_kprobe(void *addr)
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{
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return NULL;
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}
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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 int register_kprobes(struct kprobe **kps, int num)
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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 void unregister_kprobes(struct kprobe **kps, int num)
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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 int register_kretprobes(struct kretprobe **rps, int num)
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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 unregister_kretprobes(struct kretprobe **rps, int num)
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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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static inline int disable_kprobe(struct kprobe *kp)
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{
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return -ENOSYS;
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}
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static inline int enable_kprobe(struct kprobe *kp)
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{
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return -ENOSYS;
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}
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static inline bool within_kprobe_blacklist(unsigned long addr)
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{
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return true;
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}
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static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value,
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char *type, char *sym)
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{
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return -ERANGE;
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}
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#endif /* CONFIG_KPROBES */
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static inline int disable_kretprobe(struct kretprobe *rp)
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{
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return disable_kprobe(&rp->kp);
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}
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static inline int enable_kretprobe(struct kretprobe *rp)
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{
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return enable_kprobe(&rp->kp);
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}
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#ifndef CONFIG_KPROBES
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static inline bool is_kprobe_insn_slot(unsigned long addr)
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{
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return false;
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}
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#endif
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#ifndef CONFIG_OPTPROBES
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static inline bool is_kprobe_optinsn_slot(unsigned long addr)
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{
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return false;
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}
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#endif
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/* Returns true if kprobes handled the fault */
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static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
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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 */
|