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| author | Andrii Nakryiko <andriin@fb.com> | 2019-04-02 09:49:50 -0700 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2019-04-03 00:53:07 +0200 |
| commit | e83b9f55448afce3fe1abcd1d10db9584f8042a6 (patch) | |
| tree | 4a8ccfba6f274d3b7d4e61c0d11789d9bc0706bb /Makefile | |
| parent | 99182beed858a1bde22f60046602b9b223225f73 (diff) | |
| download | linux-e83b9f55448afce3fe1abcd1d10db9584f8042a6.tar.gz | |
kbuild: add ability to generate BTF type info for vmlinux
This patch adds new config option to trigger generation of BTF type information from DWARF debuginfo for vmlinux and kernel modules through pahole, which in turn relies on libbpf for btf_dedup() algorithm. The intent is to record compact type information of all types used inside kernel, including all the structs/unions/typedefs/etc. This enables BPF's compile-once-run-everywhere ([0]) approach, in which tracing programs that are inspecting kernel's internal data (e.g., struct task_struct) can be compiled on a system running some kernel version, but would be possible to run on other kernel versions (and configurations) without recompilation, even if the layout of structs changed and/or some of the fields were added, removed, or renamed. This is only possible if BPF loader can get kernel type info to adjust all the offsets correctly. This patch is a first time in this direction, making sure that BTF type info is part of Linux kernel image in non-loadable ELF section. BTF deduplication ([1]) algorithm typically provides 100x savings compared to DWARF data, so resulting .BTF section is not big as is typically about 2MB in size. [0] http://vger.kernel.org/lpc-bpf2018.html#session-2 [1] https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexei Starovoitov <ast@fb.com> Cc: Yonghong Song <yhs@fb.com> Cc: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/Makefile b/Makefile index c0a34064c574..73c013378559 100644 --- a/Makefile +++ b/Makefile @@ -399,6 +399,7 @@ NM = $(CROSS_COMPILE)nm STRIP = $(CROSS_COMPILE)strip OBJCOPY = $(CROSS_COMPILE)objcopy OBJDUMP = $(CROSS_COMPILE)objdump +PAHOLE = pahole LEX = flex YACC = bison AWK = awk @@ -453,7 +454,7 @@ KBUILD_LDFLAGS := GCC_PLUGINS_CFLAGS := export ARCH SRCARCH CONFIG_SHELL HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE AS LD CC -export CPP AR NM STRIP OBJCOPY OBJDUMP KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS +export CPP AR NM STRIP OBJCOPY OBJDUMP PAHOLE KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS export MAKE LEX YACC AWK INSTALLKERNEL PERL PYTHON PYTHON2 PYTHON3 UTS_MACHINE export HOSTCXX KBUILD_HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS |