tools/testing/selftests/bpf/bpf_util.h

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