1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (C) 2023. Huawei Technologies Co., Ltd */ 3 #include <linux/types.h> 4 #include <bpf/bpf_helpers.h> 5 6 #include "bpf_experimental.h" 7 #include "bpf_misc.h" 8 9 char _license[] SEC("license") = "GPL"; 10 11 struct bin_data { 12 char blob[32]; 13 }; 14 15 #define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8))) 16 private(kptr) struct bin_data __kptr * ptr; 17 18 SEC("tc") 19 __naked int kptr_xchg_inline(void) 20 { 21 asm volatile ( 22 "r1 = %[ptr] ll;" 23 "r2 = 0;" 24 "call %[bpf_kptr_xchg];" 25 "if r0 == 0 goto 1f;" 26 "r1 = r0;" 27 "r2 = 0;" 28 "call %[bpf_obj_drop_impl];" 29 "1:" 30 "r0 = 0;" 31 "exit;" 32 : 33 : __imm_addr(ptr), 34 __imm(bpf_kptr_xchg), 35 __imm(bpf_obj_drop_impl) 36 : __clobber_all 37 ); 38 } 39 40 /* BTF FUNC records are not generated for kfuncs referenced 41 * from inline assembly. These records are necessary for 42 * libbpf to link the program. The function below is a hack 43 * to ensure that BTF FUNC records are generated. 44 */ 45 void __btf_root(void) 46 { 47 bpf_obj_drop(NULL); 48 } 49