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Diffstat (limited to 'samples/bpf/README.rst')
| -rw-r--r-- | samples/bpf/README.rst | 49 |
1 files changed, 39 insertions, 10 deletions
diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst index 5f27e4faca50..dd34b2d26f1c 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 -------------- @@ -32,12 +46,10 @@ 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. + make M=samples/bpf It is also possible to call make from this directory. This will just -hide the the invocation of make as above with the appended "/". +hide the invocation of make as above. Manually compiling LLVM with 'bpf' support ------------------------------------------ @@ -63,14 +75,31 @@ Quick sniplet for manually compiling LLVM and clang 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 + make M=samples/bpf LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang 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 RFS 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 M=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 M=samples/bpf SYSROOT=~/some_sysroot |