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

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * bpf-script-test-prologue.c
0004  * Test BPF prologue
0005  */
0006 #ifndef LINUX_VERSION_CODE
0007 # error Need LINUX_VERSION_CODE
0008 # error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
0009 #endif
0010 #define SEC(NAME) __attribute__((section(NAME), used))
0011
0012 #include <uapi/linux/fs.h>
0013
0014 /*
0015  * If CONFIG_PROFILE_ALL_BRANCHES is selected,
0016  * 'if' is redefined after include kernel header.
0017  * Recover 'if' for BPF object code.
0018  */
0019 #ifdef if
0020 # undef if
0021 #endif
0022
0023 #define FMODE_READ      0x1
0024 #define FMODE_WRITE     0x2
0025
0026 static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
0027     (void *) 6;
0028
0029 SEC("func=null_lseek file->f_mode offset orig")
0030 int bpf_func__null_lseek(void *ctx, int err, unsigned long _f_mode,
0031              unsigned long offset, unsigned long orig)
0032 {
0033     fmode_t f_mode = (fmode_t)_f_mode;
0034
0035     if (err)
0036         return 0;
0037     if (f_mode & FMODE_WRITE)
0038         return 0;
0039     if (offset & 1)
0040         return 0;
0041     if (orig == SEEK_CUR)
0042         return 0;
0043     return 1;
0044 }
0045
0046 char _license[] SEC("license") = "GPL";
0047 int _version SEC("version") = LINUX_VERSION_CODE;