root/tools/testing/selftests/bpf/progs/test_core_reloc_flavors.c

DEFINITIONS

1. SEC

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2019 Facebook
   3 
   4 #include <linux/bpf.h>
   5 #include <stdint.h>
   6 #include "bpf_helpers.h"
   7 
   8 char _license[] SEC("license") = "GPL";
   9 
  10 static volatile struct data {
  11         char in[256];
  12         char out[256];
  13 } data;
  14 
  15 struct core_reloc_flavors {
  16         int a;
  17         int b;
  18         int c;
  19 };
  20 
  21 /* local flavor with reversed layout */
  22 struct core_reloc_flavors___reversed {
  23         int c;
  24         int b;
  25         int a;
  26 };
  27 
  28 /* local flavor with nested/overlapping layout */
  29 struct core_reloc_flavors___weird {
  30         struct {
  31                 int b;
  32         };
  33         /* a and c overlap in local flavor, but this should still work
  34          * correctly with target original flavor
  35          */
  36         union {
  37                 int a;
  38                 int c;
  39         };
  40 };
  41 
  42 SEC("raw_tracepoint/sys_enter")
  43 int test_core_flavors(void *ctx)
  44 {
  45         struct core_reloc_flavors *in_orig = (void *)&data.in;
  46         struct core_reloc_flavors___reversed *in_rev = (void *)&data.in;
  47         struct core_reloc_flavors___weird *in_weird = (void *)&data.in;
  48         struct core_reloc_flavors *out = (void *)&data.out;
  49 
  50         /* read a using weird layout */
  51         if (BPF_CORE_READ(&out->a, &in_weird->a))
  52                 return 1;
  53         /* read b using reversed layout */
  54         if (BPF_CORE_READ(&out->b, &in_rev->b))
  55                 return 1;
  56         /* read c using original layout */
  57         if (BPF_CORE_READ(&out->c, &in_orig->c))
  58                 return 1;
  59 
  60         return 0;
  61 }
  62