tools/testing/selftests/bpf/bpf_util.h

   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
  10 static 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__ */