51 lines · c
1// SPDX-License-Identifier: GPL-2.02/* Copyright (c) 2021 Facebook */3 4#include "vmlinux.h"5#include <bpf/bpf_helpers.h>6 7#define X_0(x)8#define X_1(x) x X_0(x)9#define X_2(x) x X_1(x)10#define X_3(x) x X_2(x)11#define X_4(x) x X_3(x)12#define X_5(x) x X_4(x)13#define X_6(x) x X_5(x)14#define X_7(x) x X_6(x)15#define X_8(x) x X_7(x)16#define X_9(x) x X_8(x)17#define X_10(x) x X_9(x)18#define REPEAT_256(Y) X_2(X_10(X_10(Y))) X_5(X_10(Y)) X_6(Y)19 20extern const int bpf_testmod_ksym_percpu __ksym;21extern void bpf_testmod_test_mod_kfunc(int i) __ksym;22extern void bpf_testmod_invalid_mod_kfunc(void) __ksym __weak;23 24int out_bpf_testmod_ksym = 0;25const volatile int x = 0;26 27SEC("tc")28int load(struct __sk_buff *skb)29{30 /* This will be kept by clang, but removed by verifier. Since it is31 * marked as __weak, libbpf and gen_loader don't error out if BTF ID32 * is not found for it, instead imm and off is set to 0 for it.33 */34 if (x)35 bpf_testmod_invalid_mod_kfunc();36 bpf_testmod_test_mod_kfunc(42);37 out_bpf_testmod_ksym = *(int *)bpf_this_cpu_ptr(&bpf_testmod_ksym_percpu);38 return 0;39}40 41SEC("tc")42int load_256(struct __sk_buff *skb)43{44 /* this will fail if kfunc doesn't reuse its own btf fd index */45 REPEAT_256(bpf_testmod_test_mod_kfunc(42););46 bpf_testmod_test_mod_kfunc(42);47 return 0;48}49 50char LICENSE[] SEC("license") = "GPL";51