71 lines
1.8 KiB
C
71 lines
1.8 KiB
C
|
// SPDX-License-Identifier: GPL-2.0-or-later
|
||
|
|
/*
|
||
|
|
* Dynamic Ftrace based Kprobes Optimization
|
||
|
|
*
|
||
|
|
* Copyright (C) Hitachi Ltd., 2012
|
||
|
|
*/
|
||
|
|
#include <linux/kprobes.h>
|
||
|
|
#include <linux/ptrace.h>
|
||
|
|
#include <linux/hardirq.h>
|
||
|
|
#include <linux/preempt.h>
|
||
|
|
#include <linux/ftrace.h>
|
||
|
|
|
||
|
|
#include "common.h"
|
||
|
|
|
||
|
|
/* Ftrace callback handler for kprobes -- called under preempt disabled */
|
||
|
|
void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
|
||
|
|
struct ftrace_ops *ops, struct ftrace_regs *fregs)
|
||
|
|
{
|
||
|
|
struct pt_regs *regs = ftrace_get_regs(fregs);
|
||
|
|
struct kprobe *p;
|
||
|
|
struct kprobe_ctlblk *kcb;
|
||
|
|
int bit;
|
||
|
|
|
||
|
|
bit = ftrace_test_recursion_trylock(ip, parent_ip);
|
||
|
|
if (bit < 0)
|
||
|
|
return;
|
||
|
|
|
||
|
|
p = get_kprobe((kprobe_opcode_t *)ip);
|
||
|
|
if (unlikely(!p) || kprobe_disabled(p))
|
||
|
|
goto out;
|
||
|
|
|
||
|
|
kcb = get_kprobe_ctlblk();
|
||
|
|
if (kprobe_running()) {
|
||
|
|
kprobes_inc_nmissed_count(p);
|
||
|
|
} else {
|
||
|
|
unsigned long orig_ip = regs->ip;
|
||
|
|
/* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
|
||
|
|
regs->ip = ip + sizeof(kprobe_opcode_t);
|
||
|
|
|
||
|
|
__this_cpu_write(current_kprobe, p);
|
||
|
|
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
|
||
|
|
if (!p->pre_handler || !p->pre_handler(p, regs)) {
|
||
|
|
/*
|
||
|
|
* Emulate singlestep (and also recover regs->ip)
|
||
|
|
* as if there is a 5byte nop
|
||
|
|
*/
|
||
|
|
regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
|
||
|
|
if (unlikely(p->post_handler)) {
|
||
|
|
kcb->kprobe_status = KPROBE_HIT_SSDONE;
|
||
|
|
p->post_handler(p, regs, 0);
|
||
|
|
}
|
||
|
|
regs->ip = orig_ip;
|
||
|
|
}
|
||
|
|
/*
|
||
|
|
* If pre_handler returns !0, it changes regs->ip. We have to
|
||
|
|
* skip emulating post_handler.
|
||
|
|
*/
|
||
|
|
__this_cpu_write(current_kprobe, NULL);
|
||
|
|
}
|
||
|
|
out:
|
||
|
|
ftrace_test_recursion_unlock(bit);
|
||
|
|
}
|
||
|
|
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
|
||
|
|
|
||
|
|
int arch_prepare_kprobe_ftrace(struct kprobe *p)
|
||
|
|
{
|
||
|
|
p->ainsn.insn = NULL;
|
||
|
|
p->ainsn.boostable = false;
|
||
|
|
return 0;
|
||
|
|
}
|