Since v1 [1], I added Quentin's acks and applied Andrii's suggestions: * Pass CFLAGS to libbpf link in patch 3 * Substitute CLANG_CROSS_FLAGS whole in HOST_CFLAGS to avoid accidents, patch 4
Add support for cross-building BPF tools and selftests with clang, by passing LLVM=1 or CC=clang to make, as well as CROSS_COMPILE. A single clang toolchain can generate binaries for multiple architectures, so instead of having prefixes such as aarch64-linux-gnu-gcc, clang uses the -target parameter: `clang -target aarch64-linux-gnu'.
Patch 1 adds the parameter in Makefile.include so tools can easily support this. Patch 2 prepares for the libbpf change from patch 3 (keep building resolve_btfids's libbpf in the host arch, when cross-building the kernel with clang). Patches 3-6 enable cross-building BPF tools with clang.
[1] https://lore.kernel.org/bpf/20211122192019.1277299-1-jean-philippe@linaro.or...
Jean-Philippe Brucker (6): tools: Help cross-building with clang tools/resolve_btfids: Support cross-building the kernel with clang tools/libbpf: Enable cross-building with clang bpftool: Enable cross-building with clang tools/runqslower: Enable cross-building with clang selftests/bpf: Enable cross-building with clang
tools/bpf/bpftool/Makefile | 13 +++++++------ tools/bpf/resolve_btfids/Makefile | 1 + tools/bpf/runqslower/Makefile | 4 ++-- tools/lib/bpf/Makefile | 3 ++- tools/scripts/Makefile.include | 13 ++++++++++++- tools/testing/selftests/bpf/Makefile | 8 ++++---- 6 files changed, 28 insertions(+), 14 deletions(-)