1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/bpf.h>
3 #include <bpf/bpf_helpers.h>
4 
5 struct __bpf_stdout__ {
6 	__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
7 	__type(key, int);
8 	__type(value, __u32);
9 	__uint(max_entries, __NR_CPUS__);
10 } __bpf_stdout__ SEC(".maps");
11 
12 #define puts(from) \
13 	({ const int __len = sizeof(from); \
14 	   char __from[sizeof(from)] = from;			\
15 	   bpf_perf_event_output(args, &__bpf_stdout__, BPF_F_CURRENT_CPU, \
16 			  &__from, __len & (sizeof(from) - 1)); })
17 
18 struct syscall_enter_args;
19 
20 SEC("raw_syscalls:sys_enter")
sys_enter(struct syscall_enter_args * args)21 int sys_enter(struct syscall_enter_args *args)
22 {
23 	puts("Hello, world\n");
24 	return 0;
25 }
26 
27 char _license[] SEC("license") = "GPL";
28