1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Test weak ksyms. 4 * 5 * Copyright (c) 2021 Google 6 */ 7 8 #include "vmlinux.h" 9 10 #include <bpf/bpf_helpers.h> 11 12 int out__existing_typed = -1; 13 __u64 out__existing_typeless = -1; 14 15 __u64 out__non_existent_typeless = -1; 16 __u64 out__non_existent_typed = -1; 17 18 /* existing weak symbols */ 19 20 /* test existing weak symbols can be resolved. */ 21 extern const struct rq runqueues __ksym __weak; /* typed */ 22 extern const void bpf_prog_active __ksym __weak; /* typeless */ 23 struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym __weak; 24 void bpf_testmod_test_mod_kfunc(int i) __ksym __weak; 25 26 27 /* non-existent weak symbols. */ 28 29 /* typeless symbols, default to zero. */ 30 extern const void bpf_link_fops1 __ksym __weak; 31 32 /* typed symbols, default to zero. */ 33 extern const int bpf_link_fops2 __ksym __weak; 34 void invalid_kfunc(void) __ksym __weak; 35 36 SEC("raw_tp/sys_enter") pass_handler(const void * ctx)37int pass_handler(const void *ctx) 38 { 39 struct rq *rq; 40 41 /* tests existing symbols. */ 42 rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, 0); 43 if (rq && bpf_ksym_exists(&runqueues)) 44 out__existing_typed = rq->cpu; 45 out__existing_typeless = (__u64)&bpf_prog_active; 46 47 /* tests non-existent symbols. */ 48 out__non_existent_typeless = (__u64)&bpf_link_fops1; 49 50 /* tests non-existent symbols. */ 51 out__non_existent_typed = (__u64)&bpf_link_fops2; 52 53 if (&bpf_link_fops2) /* can't happen */ 54 out__non_existent_typed = (__u64)bpf_per_cpu_ptr(&bpf_link_fops2, 0); 55 56 if (!bpf_ksym_exists(bpf_task_acquire)) 57 /* dead code won't be seen by the verifier */ 58 bpf_task_acquire(0); 59 60 if (!bpf_ksym_exists(bpf_testmod_test_mod_kfunc)) 61 /* dead code won't be seen by the verifier */ 62 bpf_testmod_test_mod_kfunc(0); 63 64 if (bpf_ksym_exists(invalid_kfunc)) 65 /* dead code won't be seen by the verifier */ 66 invalid_kfunc(); 67 68 return 0; 69 } 70 71 char _license[] SEC("license") = "GPL"; 72