1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
|
// SPDX-License-Identifier: GPL-2.0
#include <linux/kprobes.h>
int arch_check_ftrace_location(struct kprobe *p)
{
if (ftrace_location((unsigned long)p->addr))
p->flags |= KPROBE_FLAG_FTRACE;
return 0;
}
/* Ftrace callback handler for kprobes -- called under preepmt disabed */
void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *ops, struct ftrace_regs *fregs)
{
int bit;
bool lr_saver = false;
struct kprobe *p;
struct kprobe_ctlblk *kcb;
struct pt_regs *regs;
bit = ftrace_test_recursion_trylock(ip, parent_ip);
if (bit < 0)
return;
regs = ftrace_get_regs(fregs);
preempt_disable_notrace();
p = get_kprobe((kprobe_opcode_t *)ip);
if (!p) {
p = get_kprobe((kprobe_opcode_t *)(ip - MCOUNT_INSN_SIZE));
if (unlikely(!p) || kprobe_disabled(p))
goto out;
lr_saver = true;
}
kcb = get_kprobe_ctlblk();
if (kprobe_running()) {
kprobes_inc_nmissed_count(p);
} else {
unsigned long orig_ip = instruction_pointer(regs);
if (lr_saver)
ip -= MCOUNT_INSN_SIZE;
instruction_pointer_set(regs, ip);
__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->pc)
* as if there is a nop
*/
instruction_pointer_set(regs,
(unsigned long)p->addr + MCOUNT_INSN_SIZE);
if (unlikely(p->post_handler)) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
p->post_handler(p, regs, 0);
}
instruction_pointer_set(regs, orig_ip);
}
/*
* If pre_handler returns !0, it changes regs->pc. We have to
* skip emulating post_handler.
*/
__this_cpu_write(current_kprobe, NULL);
}
out:
preempt_enable_notrace();
ftrace_test_recursion_unlock(bit);
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
int arch_prepare_kprobe_ftrace(struct kprobe *p)
{
p->ainsn.api.insn = NULL;
return 0;
}
|
