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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * bpf-script-test-prologue.c
   4  * Test BPF prologue
   5  */
   6 #ifndef LINUX_VERSION_CODE
   7 # error Need LINUX_VERSION_CODE
   8 # error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
   9 #endif
  10 #define SEC(NAME) __attribute__((section(NAME), used))
  11
  12 #include <uapi/linux/fs.h>
  13
  14 /*
  15  * If CONFIG_PROFILE_ALL_BRANCHES is selected,
  16  * 'if' is redefined after include kernel header.
  17  * Recover 'if' for BPF object code.
  18  */
  19 #ifdef if
  20 # undef if
  21 #endif
  22
  23 #define FMODE_READ              0x1
  24 #define FMODE_WRITE             0x2
  25
  26 static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
  27         (void *) 6;
  28
  29 SEC("func=null_lseek file->f_mode offset orig")
  30 int bpf_func__null_lseek(void *ctx, int err, unsigned long _f_mode,
  31                          unsigned long offset, unsigned long orig)
  32 {
  33         fmode_t f_mode = (fmode_t)_f_mode;
  34
  35         if (err)
  36                 return 0;
  37         if (f_mode & FMODE_WRITE)
  38                 return 0;
  39         if (offset & 1)
  40                 return 0;
  41         if (orig == SEEK_CUR)
  42                 return 0;
  43         return 1;
  44 }
  45
  46 char _license[] SEC("license") = "GPL";
  47 int _version SEC("version") = LINUX_VERSION_CODE;