[PATCH bpf-next 0/2] bpf, parisc: Add support for BPF_SDIV and BPF_SMOD in the parisc JITs

[Nicholas Dudar <main.kalliope@gmail.com>]

The parisc BPF JITs emit unsigned divide and remainder for signed
BPF_DIV and BPF_MOD (off == 1) on the 64-bit and 32-bit JITs, so
neither implements signed BPF_SDIV and BPF_SMOD. Signed div/mod
return an unsigned result for negative operands rather than the
verifier's and the interpreter's signed result.

Patch 1 adds signed support to the parisc64 JIT and the shared signed
64-bit helpers (hppa_sdiv64/hppa_sdiv64_rem) in bpf_jit_core.c. Patch
2 adds it to the parisc32 JIT, using those helpers for the 64-bit path
and the $$divI/$$remI signed millicode for the 32-bit path.

Both were tested with test_bpf on qemu-system-hppa; the signed div/mod
cases fail before and pass after.

Nicholas Dudar (2):
  bpf, parisc: Add support for BPF_SDIV and BPF_SMOD in the parisc64 JIT
  bpf, parisc: Add support for BPF_SDIV and BPF_SMOD in the parisc32 JIT

 arch/parisc/net/bpf_jit.h        |  2 ++
 arch/parisc/net/bpf_jit_comp32.c | 29 +++++++++++++++++---------
 arch/parisc/net/bpf_jit_comp64.c | 35 ++++++++++++++++++++++++--------
 arch/parisc/net/bpf_jit_core.c   | 14 +++++++++++++
 4 files changed, 61 insertions(+), 19 deletions(-)


base-commit: 1d91ea01185656ac3ee63c5f9f6f8bde3c746b3d
-- 
2.34.1