Add couple preparation steps: clean and configuration. Also add newly added sysroot support info to cross-compile section. --- samples/bpf/README.rst | 41 ++++++++++++++++++++++++++++++++++++----- 1 file changed, 36 insertions(+), 5 deletions(-) diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst index 5f27e4faca50..d5845d73ab7d 100644 --- a/samples/bpf/README.rst +++ b/samples/bpf/README.rst @@ -14,6 +14,20 @@ Compiling requires having installed: Note that LLVM's tool 'llc' must support target 'bpf', list version and supported targets with command: ``llc --version`` +Clean and configuration +----------------------- + +It can be needed to clean tools, samples or kernel before trying new arch or +after some changes (on demand):: + + make -C tools clean + make -C samples/bpf clean + make clean + +Configure kernel, defconfig for instance:: + + make defconfig + Kernel headers -------------- @@ -68,9 +82,26 @@ It is also possible to point make to the newly compiled 'llc' or Cross compiling samples ----------------------- In order to cross-compile, say for arm64 targets, export CROSS_COMPILE and ARCH -environment variables before calling make. This will direct make to build -samples for the cross target. +environment variables before calling make. But do this before clean, +cofiguration and header install steps described above. This will direct make to +build samples for the cross target:: + + export ARCH=arm64 + export CROSS_COMPILE="aarch64-linux-gnu-" + +Headers can be also installed on RFC of target board if need to keep them in +sync (not necessarily and it creates a local "usr/include" directory also):: + + make INSTALL_HDR_PATH=~/some_sysroot/usr headers_install + +Pointing LLC and CLANG is not necessarily if it's installed on HOST and have +in its targets appropriate arm64 arch (usually it has several arches). +Build samples:: + + make samples/bpf/ + +Or build samples with SYSROOT if some header or library is absent in toolchain, +say libelf, providing address to file system containing headers and libs, +can be RFS of target board:: -export ARCH=arm64 -export CROSS_COMPILE="aarch64-linux-gnu-" -make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang + make samples/bpf/ SYSROOT=~/some_sysroot -- 2.17.1
