Hello all,
This patch series targets a long-standing BPF usability issue - the lack
of general cross-compilation support - by enabling cross-endian usage of
libbpf and cross-endian build targets for selftests/bpf. Use cases range
from better BPF support for embedded systems based on e.g. big-endian
MIPS, to more build/test options for s390x systems.
Initial development and testing used mips64, since this arch makes
switching the build byte-order trivial and is thus very handy for A/B
testing. However, it lacks some key features (bpf2bpf call, kfuncs, etc)
making for poor selftests/bpf coverage.
Final testing takes the kernel and selftests/bpf cross-built from x86_64
to s390x, and runs the result under QEMU/s390x. That same configuration
could also be used on kernel-patches/bpf CI for regression testing endian
support or perhaps load-sharing s390x builds across x86_64 systems.
This thread includes some background regarding testing on QEMU/s390x and
the generally favourable results (3 failures running test_progs):
https://lore.kernel.org/bpf/ZsEcsaa3juxxQBUf@kodidev-ubuntu/
Feedback and suggestions are welcome!
Best regards,
Tony
Tony Ambardar (8):
libbpf: Improve log message formatting
libbpf: Fix header comment typos for BTF.ext
libbpf: Fix output .symtab byte-order during linking
libbpf: Support BTF.ext loading and output in either endianness
libbpf: Support opening bpf objects of either endianness
libbpf: Support linking bpf objects of either endianness
libbpf: Support creating light skeleton of either endianness
selftests/bpf: Support cross-endian building
tools/lib/bpf/bpf_gen_internal.h | 1 +
tools/lib/bpf/btf.c | 167 +++++++++++++++++++++++--
tools/lib/bpf/btf.h | 2 +
tools/lib/bpf/btf_dump.c | 2 +-
tools/lib/bpf/btf_relocate.c | 2 +-
tools/lib/bpf/gen_loader.c | 179 +++++++++++++++++++++------
tools/lib/bpf/libbpf.c | 26 +++-
tools/lib/bpf/libbpf.map | 2 +
tools/lib/bpf/libbpf_internal.h | 17 ++-
tools/lib/bpf/linker.c | 108 +++++++++++++---
tools/lib/bpf/relo_core.c | 2 +-
tools/lib/bpf/skel_internal.h | 3 +-
tools/testing/selftests/bpf/Makefile | 7 +-
13 files changed, 438 insertions(+), 80 deletions(-)
--
2.34.1
