| commit | 83535cb2bfa0fabbb31dbcbc6ffe759a03757c0f | [log] [tgz] |
|---|---|---|
| author | Andrii Nakryiko <andriin@fb.com> | Wed Nov 20 23:07:43 2019 -0800 |
| committer | Andrii Nakryiko <andrii.nakryiko@gmail.com> | Mon Nov 25 16:55:44 2019 -0800 |
| tree | 308321f2b0ea72cee9558489a9f9d282212c82d4 | |
| parent | 3f05b513d4b293f36668b3c69bf018a1aa39fee7 [diff] |
libbpf: Support initialized global variables Initialized global variables are no different in ELF from static variables, and don't require any extra support from libbpf. But they are matching semantics of global data (backed by BPF maps) more closely, preventing LLVM/Clang from aggressively inlining constant values and not requiring volatile incantations to prevent those. This patch enables global variables. It still disables uninitialized variables, which will be put into special COM (common) ELF section, because BPF doesn't allow uninitialized data to be accessed. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191121070743.1309473-5-andriin@fb.com
This is a mirror of bpf-next linux tree's tools/lib/bpf directory plus its supporting header files.
The following files will by sync'ed with bpf-next repo:
src/ <-> bpf-next/tools/lib/bpf/include/uapi/linux/bpf_common.h <-> bpf-next/tools/include/uapi/linux/bpf_common.hinclude/uapi/linux/bpf.h <-> bpf-next/tools/include/uapi/linux/bpf.hinclude/uapi/linux/btf.h <-> bpf-next/tools/include/uapi/linux/btf.hinclude/uapi/linux/if_link.h <-> bpf-next/tools/include/uapi/linux/if_link.hinclude/uapi/linux/if_xdp.h <-> bpf-next/tools/include/uapi/linux/if_xdp.hinclude/uapi/linux/netlink.h <-> bpf-next/tools/include/uapi/linux/netlink.hinclude/tools/libc_compat.h <-> bpf-next/tools/include/tools/libc_compat.hOther header files at this repo (include/linux/*.h) are reduced versions of their counterpart files at bpf-next's tools/include/linux/*.h to make compilation successful.
libelf is an internal dependency of libbpf and thus it is required to link against and must be installed on the system for applications to work. pkg-config is used by default to find libelf, and the program called can be overridden with PKG_CONFIG. If using pkg-config at build time is not desired, it can be disabled by setting NO_PKG_CONFIG=1 when calling make.
To build both static libbpf.a and shared libbpf.so:
$ cd src
$ make
To build only static libbpf.a library in directory build/ and install them together with libbpf headers in a staging directory root/:
$ cd src $ mkdir build root $ BUILD_STATIC_ONLY=y OBJDIR=build DESTDIR=root make install
To build both static libbpf.a and shared libbpf.so against a custom libelf dependency installed in /build/root/ and install them together with libbpf headers in a build directory /build/root/:
$ cd src $ PKG_CONFIG_PATH=/build/root/lib64/pkgconfig DESTDIR=/build/root make install