linux/samples/bpf
Daniel Borkmann 96a8eb1eee bpf: fix samples to add fake KBUILD_MODNAME
Some of the sample files are causing issues when they are loaded with tc
and cls_bpf, meaning tc bails out while trying to parse the resulting ELF
file as program/map/etc sections are not present, which can be easily
spotted with readelf(1).

Currently, BPF samples are including some of the kernel headers and mid
term we should change them to refrain from this, really. When dynamic
debugging is enabled, we bail out due to undeclared KBUILD_MODNAME, which
is easily overlooked in the build as clang spills this along with other
noisy warnings from various header includes, and llc still generates an
ELF file with mentioned characteristics. For just playing around with BPF
examples, this can be a bit of a hurdle to take.

Just add a fake KBUILD_MODNAME as a band-aid to fix the issue, same is
done in xdp*_kern samples already.

Fixes: 65d472fb00 ("samples/bpf: add 'pointer to packet' tests")
Fixes: 6afb1e28b8 ("samples/bpf: Add tunnel set/get tests.")
Fixes: a3f7461734 ("cgroup: bpf: Add an example to do cgroup checking in BPF")
Reported-by: Chandrasekar Kannan <ckannan@console.to>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-29 14:46:12 -04:00
..
bpf_helpers.h samples/bpf: add perf_event+bpf example 2016-09-02 10:46:45 -07:00
bpf_load.c samples/bpf: add perf_event+bpf example 2016-09-02 10:46:45 -07:00
bpf_load.h samples/bpf: move ksym_search() into library 2016-03-08 15:28:32 -05:00
fds_example.c samples/bpf: add map_flags to bpf loader 2016-03-08 15:28:32 -05:00
lathist_kern.c bpf: BPF based latency tracing 2015-06-23 06:09:58 -07:00
lathist_user.c bpf: BPF based latency tracing 2015-06-23 06:09:58 -07:00
libbpf.c samples/bpf: add map_flags to bpf loader 2016-03-08 15:28:32 -05:00
libbpf.h bpf: allow access into map value arrays 2016-09-29 01:35:35 -04:00
Makefile samples/bpf: add sampleip example 2016-09-02 10:46:45 -07:00
map_perf_test_kern.c samples/bpf: add map performance test 2016-03-08 23:22:03 -05:00
map_perf_test_user.c samples/bpf: Fix build breakage with map_perf_test_user.c 2016-04-06 16:01:28 -04:00
offwaketime_kern.c bpf, samples: don't zero data when not needed 2016-04-14 21:40:42 -04:00
offwaketime_user.c samples/bpf: move ksym_search() into library 2016-03-08 15:28:32 -05:00
parse_ldabs.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
parse_simple.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
parse_varlen.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
README.rst samples/bpf: like LLC also verify and allow redefining CLANG command 2016-04-29 14:26:08 -04:00
sampleip_kern.c samples/bpf: add sampleip example 2016-09-02 10:46:45 -07:00
sampleip_user.c samples/bpf: add sampleip example 2016-09-02 10:46:45 -07:00
sock_example.c samples/bpf: add map_flags to bpf loader 2016-03-08 15:28:32 -05:00
sockex1_kern.c samples: bpf: add skb->field examples and tests 2015-03-15 22:02:28 -04:00
sockex1_user.c samples: bpf: add skb->field examples and tests 2015-03-15 22:02:28 -04:00
sockex2_kern.c bpf samples: fix compiler errors with sockex2 and sockex3 2016-09-27 03:48:58 -04:00
sockex2_user.c samples/bpf: set max locked memory to ulimited 2016-06-25 12:03:46 -04:00
sockex3_kern.c bpf samples: fix compiler errors with sockex2 and sockex3 2016-09-27 03:48:58 -04:00
sockex3_user.c bpf samples: fix compiler errors with sockex2 and sockex3 2016-09-27 03:48:58 -04:00
spintest_kern.c samples/bpf: Enable powerpc support 2016-04-06 16:01:29 -04:00
spintest_user.c samples/bpf: add bpf map stress test 2016-03-08 23:22:02 -05:00
tcbpf1_kern.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
tcbpf2_kern.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
test_cgrp2_array_pin.c cgroup: bpf: Add an example to do cgroup checking in BPF 2016-07-01 16:32:13 -04:00
test_cgrp2_tc_kern.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
test_cgrp2_tc.sh cgroup: bpf: Add an example to do cgroup checking in BPF 2016-07-01 16:32:13 -04:00
test_cls_bpf.sh samples/bpf: add 'pointer to packet' tests 2016-05-06 16:01:54 -04:00
test_current_task_under_cgroup_kern.c samples/bpf: Add test_current_task_under_cgroup test 2016-08-12 21:49:42 -07:00
test_current_task_under_cgroup_user.c samples/bpf: Add test_current_task_under_cgroup test 2016-08-12 21:49:42 -07:00
test_ipip.sh samples/bpf: add comprehensive ipip, ipip6, ip6ip6 test 2016-09-17 10:13:07 -04:00
test_maps.c samples/bpf: add bpf_map_update_elem() tests 2016-08-06 20:49:19 -04:00
test_overhead_kprobe_kern.c samples/bpf: add tracepoint vs kprobe performance tests 2016-04-07 21:04:27 -04:00
test_overhead_tp_kern.c samples/bpf: add tracepoint vs kprobe performance tests 2016-04-07 21:04:27 -04:00
test_overhead_user.c samples/bpf: add tracepoint vs kprobe performance tests 2016-04-07 21:04:27 -04:00
test_probe_write_user_kern.c samples/bpf: Add test/example of using bpf_probe_write_user bpf helper 2016-07-25 18:07:48 -07:00
test_probe_write_user_user.c samples/bpf: Add test/example of using bpf_probe_write_user bpf helper 2016-07-25 18:07:48 -07:00
test_tunnel_bpf.sh samples/bpf: extend test_tunnel_bpf.sh with IPIP test 2016-09-17 10:13:07 -04:00
test_verifier.c bpf: allow access into map value arrays 2016-09-29 01:35:35 -04:00
trace_event_kern.c samples/bpf: add perf_event+bpf example 2016-09-02 10:46:45 -07:00
trace_event_user.c samples/bpf: add perf_event+bpf example 2016-09-02 10:46:45 -07:00
trace_output_kern.c samples/bpf: fix trace_output example 2016-04-28 17:29:45 -04:00
trace_output_user.c samples: bpf: add bpf_perf_event_output example 2015-10-22 06:42:15 -07:00
tracex1_kern.c bpf, samples: don't zero data when not needed 2016-04-14 21:40:42 -04:00
tracex1_user.c samples/bpf: Add simple non-portable kprobe filter example 2015-04-02 13:25:50 +02:00
tracex2_kern.c bpf, samples: don't zero data when not needed 2016-04-14 21:40:42 -04:00
tracex2_user.c samples/bpf: update tracex[23] examples to use per-cpu maps 2016-02-06 03:34:36 -05:00
tracex3_kern.c samples/bpf: update tracex[23] examples to use per-cpu maps 2016-02-06 03:34:36 -05:00
tracex3_user.c samples/bpf: update tracex[23] examples to use per-cpu maps 2016-02-06 03:34:36 -05:00
tracex4_kern.c samples/bpf: Enable powerpc support 2016-04-06 16:01:29 -04:00
tracex4_user.c samples/bpf: Add kmem_alloc()/free() tracker tool 2015-04-02 13:25:51 +02:00
tracex5_kern.c bpf samples: update tracex5 sample to use __seccomp_filter 2016-09-27 03:48:58 -04:00
tracex5_user.c bpf samples: update tracex5 sample to use __seccomp_filter 2016-09-27 03:48:58 -04:00
tracex6_kern.c bpf: fix build warnings and add function read_trace_pipe() 2015-08-12 16:39:12 -07:00
tracex6_user.c bpf: fix build warnings and add function read_trace_pipe() 2015-08-12 16:39:12 -07:00
xdp1_kern.c bpf: make xdp sample variable names more meaningful 2016-07-20 22:07:24 -07:00
xdp1_user.c Add sample for adding simple drop program to link 2016-07-19 21:46:32 -07:00
xdp2_kern.c bpf: make xdp sample variable names more meaningful 2016-07-20 22:07:24 -07:00

eBPF sample programs
====================

This directory contains a mini eBPF library, test stubs, verifier
test-suite and examples for using eBPF.

Build dependencies
==================

Compiling requires having installed:
 * clang >= version 3.4.0
 * llvm >= version 3.7.1

Note that LLVM's tool 'llc' must support target 'bpf', list version
and supported targets with command: ``llc --version``

Kernel headers
--------------

There are usually dependencies to header files of the current kernel.
To avoid installing devel kernel headers system wide, as a normal
user, simply call::

 make headers_install

This will creates a local "usr/include" directory in the git/build top
level directory, that the make system automatically pickup first.

Compiling
=========

For building the BPF samples, issue the below command from the kernel
top level directory::

 make samples/bpf/

Do notice the "/" slash after the directory name.

It is also possible to call make from this directory.  This will just
hide the the invocation of make as above with the appended "/".

Manually compiling LLVM with 'bpf' support
------------------------------------------

Since version 3.7.0, LLVM adds a proper LLVM backend target for the
BPF bytecode architecture.

By default llvm will build all non-experimental backends including bpf.
To generate a smaller llc binary one can use::

 -DLLVM_TARGETS_TO_BUILD="BPF"

Quick sniplet for manually compiling LLVM and clang
(build dependencies are cmake and gcc-c++)::

 $ git clone http://llvm.org/git/llvm.git
 $ cd llvm/tools
 $ git clone --depth 1 http://llvm.org/git/clang.git
 $ cd ..; mkdir build; cd build
 $ cmake .. -DLLVM_TARGETS_TO_BUILD="BPF;X86"
 $ make -j $(getconf _NPROCESSORS_ONLN)

It is also possible to point make to the newly compiled 'llc' or
'clang' command via redefining LLC or CLANG on the make command line::

 make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang