LXR linux/tools/perf/tests/bpf-script-test-prologue.c

   1/*
   2 * bpf-script-test-prologue.c
   3 * Test BPF prologue
   4 */
   5#ifndef LINUX_VERSION_CODE
   6# error Need LINUX_VERSION_CODE
   7# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
   8#endif
   9#define SEC(NAME) __attribute__((section(NAME), used))
  10
  11#include <uapi/linux/fs.h>
  12
  13/*
  14 * If CONFIG_PROFILE_ALL_BRANCHES is selected,
  15 * 'if' is redefined after include kernel header.
  16 * Recover 'if' for BPF object code.
  17 */
  18#ifdef if
  19# undef if
  20#endif
  21
  22#define FMODE_READ              0x1
  23#define FMODE_WRITE             0x2
  24
  25static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
  26        (void *) 6;
  27
  28SEC("func=null_lseek file->f_mode offset orig")
  29int bpf_func__null_lseek(void *ctx, int err, unsigned long f_mode,
  30                         unsigned long offset, unsigned long orig)
  31{
  32        if (err)
  33                return 0;
  34        if (f_mode & FMODE_WRITE)
  35                return 0;
  36        if (offset & 1)
  37                return 0;
  38        if (orig == SEEK_CUR)
  39                return 0;
  40        return 1;
  41}
  42
  43char _license[] SEC("license") = "GPL";
  44int _version SEC("version") = LINUX_VERSION_CODE;
  45