[PATCH v4 0/7] bpf: JIT related bug fixes

[Stephen Hemminger <stephen@networkplumber.org>]

While implementing JIT for packet capture ran into several issues:
  1. x86 JIT had pre-existing bug which would crash
  2. ARM64 BPF JIT was missing instructions for packet access.
     Which had been discovered previously [1]
  3. Tests related to JIT were not being run or missing coverage.

Fixed all of these. Patches are ordered so that most urgent fix
is first, followed by the test that should have caught the problem.

The arm64 epilogue branch fix (patch 4) was originally posted by
Christophe Fontaine [1]; that series stalled, so it is carried here
with his authorship.

Changes since v3:
 - incorporate review feedback
 - rebase to current main
 - extend the x86 fix to all fixed-width immediates, not just JSET:
   TEST is always imm32, while ROR and the shift group are always
   imm8; patch 1 retitled to match
 - add a regression test for a large shift count (patch 3)

Changes since v2:
 - found more places where the x86 JIT emitted invalid opcodes for
   fixed-width immediates

Changes since v1:
 - add the x86 JSET encoding fix and its regression test, found once
   the convert test ran generated code through the JIT
 - carry Christophe's arm64 epilogue fix with his sign-off
 - convert test now runs the converted filters through the JIT, not
   just loading them
 - kept Marat's ack on the "check JIT was generated" patch; dropped it
   on the convert test since that changed substantially

[1] https://inbox.dpdk.org/dev/20260319114500.9757-2-cfontain@redhat.com/

Christophe Fontaine (1):
  bpf/arm64: fix offset type to allow a negative jump

Stephen Hemminger (6):
  bpf/x86: fix JIT encoding of fixed-width immediates
  test/bpf: add JSET test with small immediate
  test/bpf: add test for large shift
  test/bpf: check that JIT was generated
  bpf/arm64: add BPF_ABS/BPF_IND packet load support
  test/bpf: check that bpf_convert can be JIT'd

 app/test/test_bpf.c     | 327 +++++++++++++++++++++++++++++++---------
 lib/bpf/bpf_jit_arm64.c | 153 ++++++++++++++++++-
 lib/bpf/bpf_jit_x86.c   |   6 +-
 lib/bpf/meson.build     |   2 +
 4 files changed, 412 insertions(+), 76 deletions(-)

-- 
2.53.0