[PATCH 0/4] bpf/arm64: add BPF_ABS/BPF_IND packet load support

[Stephen Hemminger]

Discovered this while exploring packet filtering.
The arm64 BPF JIT did not implement BPF_LD | BPF_ABS or BPF_LD | BPF_IND,
so cBPF filters converted by rte_bpf_convert() could not be JIT compiled
and silently fell back to the interpreter on arm64.

The first patch fixes a latent bug in emit_return_zero_if_src_zero():
the offset of the branch to the epilogue was held in an unsigned.
A backward branch wrapped around. Existing JIT tests were never
being run on ARM.

The next two patches make the bpf tests assert that,
on an architecture with a JITbackend, code is actually generated,
so a missing or failed JIT is reported rather than skipped.

The final patch adds the ABS/IND opcodes, mirroring the x86 JIT
with a fast path for data in the first
mbuf segment and a __rte_pktmbuf_read() slow path for the rest.


Stephen Hemminger (4):
  bpf/arm64: fix zero-return branch in multi-exit programs
  test: bpf check that JIT was generated
  test: bpf check that bpf_convert can be JIT'd
  bpf/arm64: add BPF_ABS/BPF_IND packet load support

 app/test/test_bpf.c     |  23 ++++++-
 lib/bpf/bpf_jit_arm64.c | 149 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 169 insertions(+), 3 deletions(-)

-- 
2.53.0