path: root/samples
diff options
authorJesper Dangaard Brouer <brouer@redhat.com>2016-04-28 14:21:04 +0200
committerDavid S. Miller <davem@davemloft.net>2016-04-29 14:25:32 -0400
commit1c97566d515de2ef66873e30288b150f0154f3b3 (patch)
treefc261307afeec86f598abe3d87832c98fd19f4af /samples
parent7b01dd5793394ee2ef47c328b28c30f5c01107c9 (diff)
samples/bpf: add a README file to get users started
Getting started with using examples in samples/bpf/ is not straightforward. There are several dependencies, and specific versions of these dependencies. Just compiling the example tool is also slightly obscure, e.g. one need to call make like: make samples/bpf/ Do notice the "/" slash after the directory name. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'samples')
1 files changed, 63 insertions, 0 deletions
diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst
new file mode 100644
index 000000000000..6f133f3f0075
--- /dev/null
+++ b/samples/bpf/README.rst
@@ -0,0 +1,63 @@
+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.
+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.
+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::
+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' command
+via redefining LLC on the make command line::
+ make samples/bpf/ LLC=~/git/llvm/build/bin/llc