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
77
78
79
80
81
82
83
84
85
86
87
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2022, 2024, Oracle and/or its affiliates.
*/
#include <bpf_asm_helpers.h>
.text
.align 4
.global dt_progenyof
.type dt_progenyof, @function
dt_progenyof:
#define ARG %r6
#define CNT %r7
#define PTR %r8
#define VAL %r9
/* uint64_t dt_progenyof(pid_t arg); */
mov ARG, %r1
lsh ARG, 32
rsh ARG, 32
/* assure the BPF verifier there is no infinite loop */
mov CNT, 256
/* ptr = bpf_get_current_task() */
call BPF_FUNC_get_current_task
mov PTR, %r0
.Lloop:
/* if (ptr == 0) goto Lret0 */
jeq PTR, 0, .Lret0
/* if (count <= 0) goto Lret0 */
jsle CNT, 0, .Lret0
/* val = *((uint32_t *)(ptr + TASK_PID)), using [%fp+-8] as temp */
mov %r1, %fp
add %r1, -8
mov %r2, 4
lddw %r3, TASK_PID
add %r3, PTR
call BPF_FUNC_probe_read
jne %r0, 0, .Lret0
ldxw VAL, [%fp+-8]
lsh VAL, 32
rsh VAL, 32
/* if (val == arg) goto Lret1 */
jeq VAL, ARG, .Lret1
/* val = *((uint64_t *)(ptr + TASK_REAL_PARENT)), using [%fp+-8] as temp */
mov %r1, %fp
add %r1, -8
mov %r2, 8
lddw %r3, TASK_REAL_PARENT
add %r3, PTR
call BPF_FUNC_probe_read
jne %r0, 0, .Lret0
ldxdw VAL, [%fp+-8]
/* if (val == ptr) goto Lret0 */
jeq VAL, PTR, .Lret0
/* ptr = val */
mov PTR, VAL
/* count-- */
sub CNT, 1
/* goto Lloop */
ja .Lloop
.Lret0:
/* return 0 */
mov %r0, 0
exit
.Lret1:
/* return 1 */
mov %r0, 1
exit
.size dt_progenyof, .-dt_progenyof
#undef ARG
#undef CNT
#undef PTR
#undef VAL
|
