1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __BPF_UTIL__
3#define __BPF_UTIL__
4
5#include <stdio.h>
6#include <stdlib.h>
7#include <string.h>
8#include <errno.h>
9
10static inline unsigned int bpf_num_possible_cpus(void)
11{
12	static const char *fcpu = "/sys/devices/system/cpu/possible";
13	unsigned int start, end, possible_cpus = 0;
14	char buff[128];
15	FILE *fp;
16	int n;
17
18	fp = fopen(fcpu, "r");
19	if (!fp) {
20		printf("Failed to open %s: '%s'!\n", fcpu, strerror(errno));
21		exit(1);
22	}
23
24	while (fgets(buff, sizeof(buff), fp)) {
25		n = sscanf(buff, "%u-%u", &start, &end);
26		if (n == 0) {
27			printf("Failed to retrieve # possible CPUs!\n");
28			exit(1);
29		} else if (n == 1) {
30			end = start;
31		}
32		possible_cpus = start == 0 ? end + 1 : 0;
33		break;
34	}
35	fclose(fp);
36
37	return possible_cpus;
38}
39
40#define __bpf_percpu_val_align	__attribute__((__aligned__(8)))
41
42#define BPF_DECLARE_PERCPU(type, name)				\
43	struct { type v; /* padding */ } __bpf_percpu_val_align	\
44		name[bpf_num_possible_cpus()]
45#define bpf_percpu(name, cpu) name[(cpu)].v
46
47#endif /* __BPF_UTIL__ */
48