bdefbbf2ec
Users are likely to manually compile both LLVM 'llc' and 'clang' tools. Thus, also allow redefining CLANG and verify command exist. Makefile implementation wise, the target that verify the command have been generalized. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
67 lines
1.9 KiB
ReStructuredText
67 lines
1.9 KiB
ReStructuredText
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
|