[net-next,V4,3/5] samples/bpf: add a README file to get users started
diff mbox

Message ID 20160428122103.16807.41837.stgit@firesoul
State New
Headers show

Commit Message

Jesper Dangaard Brouer April 28, 2016, 12:21 p.m. UTC
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>
---
 samples/bpf/README.rst |   64 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 samples/bpf/README.rst


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Comments

Naveen N. Rao April 28, 2016, 1:37 p.m. UTC | #1
On 2016/04/28 02:21PM, Jesper Dangaard Brouer wrote:
> 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>

> ---
>  samples/bpf/README.rst |   64 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 64 insertions(+)
>  create mode 100644 samples/bpf/README.rst
> 
> diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst
> new file mode 100644
> index 000000000000..993d280184fa
> --- /dev/null
> +++ b/samples/bpf/README.rst
> @@ -0,0 +1,64 @@
> +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.
> +
> +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' command
> +via redefining LLC on the make command line::
> +
> + make samples/bpf/ LLC=~/git/llvm/build/bin/llc
> +
> 

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Alexei Starovoitov April 28, 2016, 4:49 p.m. UTC | #2
On Thu, Apr 28, 2016 at 02:21:04PM +0200, Jesper Dangaard Brouer wrote:
> 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: Alexei Starovoitov <ast@kernel.org>

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Patch
diff mbox

diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst
new file mode 100644
index 000000000000..993d280184fa
--- /dev/null
+++ b/samples/bpf/README.rst
@@ -0,0 +1,64 @@ 
+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.
+
+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' command
+via redefining LLC on the make command line::
+
+ make samples/bpf/ LLC=~/git/llvm/build/bin/llc
+