bpf/progs/test_ksyms_module.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Copyright (c) 2021 Facebook */
0003
0004 #include "vmlinux.h"
0005 #include <bpf/bpf_helpers.h>
0006
0007 #define X_0(x)
0008 #define X_1(x) x X_0(x)
0009 #define X_2(x) x X_1(x)
0010 #define X_3(x) x X_2(x)
0011 #define X_4(x) x X_3(x)
0012 #define X_5(x) x X_4(x)
0013 #define X_6(x) x X_5(x)
0014 #define X_7(x) x X_6(x)
0015 #define X_8(x) x X_7(x)
0016 #define X_9(x) x X_8(x)
0017 #define X_10(x) x X_9(x)
0018 #define REPEAT_256(Y) X_2(X_10(X_10(Y))) X_5(X_10(Y)) X_6(Y)
0019
0020 extern const int bpf_testmod_ksym_percpu __ksym;
0021 extern void bpf_testmod_test_mod_kfunc(int i) __ksym;
0022 extern void bpf_testmod_invalid_mod_kfunc(void) __ksym __weak;
0023
0024 int out_bpf_testmod_ksym = 0;
0025 const volatile int x = 0;
0026
0027 SEC("tc")
0028 int load(struct __sk_buff *skb)
0029 {
0030     /* This will be kept by clang, but removed by verifier. Since it is
0031      * marked as __weak, libbpf and gen_loader don't error out if BTF ID
0032      * is not found for it, instead imm and off is set to 0 for it.
0033      */
0034     if (x)
0035         bpf_testmod_invalid_mod_kfunc();
0036     bpf_testmod_test_mod_kfunc(42);
0037     out_bpf_testmod_ksym = *(int *)bpf_this_cpu_ptr(&bpf_testmod_ksym_percpu);
0038     return 0;
0039 }
0040
0041 SEC("tc")
0042 int load_256(struct __sk_buff *skb)
0043 {
0044     /* this will fail if kfunc doesn't reuse its own btf fd index */
0045     REPEAT_256(bpf_testmod_test_mod_kfunc(42););
0046     bpf_testmod_test_mod_kfunc(42);
0047     return 0;
0048 }
0049
0050 char LICENSE[] SEC("license") = "GPL";