tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
3
4#include <linux/bpf.h>
5#include <bpf/bpf_helpers.h>
6#include "bpf_misc.h"
7
8struct value_t {
9 long long a[32];
10};
11
12struct {
13 __uint(type, BPF_MAP_TYPE_HASH);
14 __uint(max_entries, 1);
15 __type(key, long long);
16 __type(value, struct value_t);
17} map_hash SEC(".maps");
18
19SEC("socket")
20__description("bpf_jit_convergence je <-> jmp")
21__success __retval(0)
22__arch_x86_64
23__jited(" pushq %rbp")
24__naked void btf_jit_convergence_je_jmp(void)
25{
26 asm volatile (
27 "call %[bpf_get_prandom_u32];"
28 "if r0 == 0 goto l20_%=;"
29 "if r0 == 1 goto l21_%=;"
30 "if r0 == 2 goto l22_%=;"
31 "if r0 == 3 goto l23_%=;"
32 "if r0 == 4 goto l24_%=;"
33 "call %[bpf_get_prandom_u32];"
34 "call %[bpf_get_prandom_u32];"
35"l20_%=:"
36"l21_%=:"
37"l22_%=:"
38"l23_%=:"
39"l24_%=:"
40 "r1 = 0;"
41 "*(u64 *)(r10 - 8) = r1;"
42 "r2 = r10;"
43 "r2 += -8;"
44 "r1 = %[map_hash] ll;"
45 "call %[bpf_map_lookup_elem];"
46 "if r0 == 0 goto l1_%=;"
47 "r6 = r0;"
48 "call %[bpf_get_prandom_u32];"
49 "r7 = r0;"
50 "r5 = r6;"
51 "if r0 != 0x0 goto l12_%=;"
52 "call %[bpf_get_prandom_u32];"
53 "r1 = r0;"
54 "r2 = r6;"
55 "if r1 == 0x0 goto l0_%=;"
56"l9_%=:"
57 "r2 = *(u64 *)(r6 + 0x0);"
58 "r2 += 0x1;"
59 "*(u64 *)(r6 + 0x0) = r2;"
60 "goto l1_%=;"
61"l12_%=:"
62 "r1 = r7;"
63 "r1 += 0x98;"
64 "r2 = r5;"
65 "r2 += 0x90;"
66 "r2 = *(u32 *)(r2 + 0x0);"
67 "r3 = r7;"
68 "r3 &= 0x1;"
69 "r2 *= 0xa8;"
70 "if r3 == 0x0 goto l2_%=;"
71 "r1 += r2;"
72 "r1 -= r7;"
73 "r1 += 0x8;"
74 "if r1 <= 0xb20 goto l3_%=;"
75 "r1 = 0x0;"
76 "goto l4_%=;"
77"l3_%=:"
78 "r1 += r7;"
79"l4_%=:"
80 "if r1 == 0x0 goto l8_%=;"
81 "goto l9_%=;"
82"l2_%=:"
83 "r1 += r2;"
84 "r1 -= r7;"
85 "r1 += 0x10;"
86 "if r1 <= 0xb20 goto l6_%=;"
87 "r1 = 0x0;"
88 "goto l7_%=;"
89"l6_%=:"
90 "r1 += r7;"
91"l7_%=:"
92 "if r1 == 0x0 goto l8_%=;"
93 "goto l9_%=;"
94"l0_%=:"
95 "r1 = 0x3;"
96 "*(u64 *)(r10 - 0x10) = r1;"
97 "r2 = r1;"
98 "goto l1_%=;"
99"l8_%=:"
100 "r1 = r5;"
101 "r1 += 0x4;"
102 "r1 = *(u32 *)(r1 + 0x0);"
103 "*(u64 *)(r10 - 0x8) = r1;"
104"l1_%=:"
105 "r0 = 0;"
106 "exit;"
107 :
108 : __imm(bpf_get_prandom_u32),
109 __imm(bpf_map_lookup_elem),
110 __imm_addr(map_hash)
111 : __clobber_all);
112}
113
114char _license[] SEC("license") = "GPL";