[bpf-next,v2,0/2] bpf,arm64: Add support for BPF Arena

Message

Puranjay Mohan March 21, 2024, 3:31 p.m. UTC

Changes in V2
V1: https://lore.kernel.org/bpf/[e-mail]/
- Fix build warnings by using 5 in place of 32 as DONT_CLEAR marker.
  R5 is not mapped to any BPF register so it can safely be used here.

This series adds the support for PROBE_MEM32 and bpf_addr_space_cast
instructions to the ARM64 BPF JIT. These two instructions allow the
enablement of BPF Arena.

All arena related selftests are passing.

  [root@ip-172-31-6-62 bpf]# ./test_progs -a "*arena*"
  #3/1     arena_htab/arena_htab_llvm:OK
  #3/2     arena_htab/arena_htab_asm:OK
  #3       arena_htab:OK
  #4/1     arena_list/arena_list_1:OK
  #4/2     arena_list/arena_list_1000:OK
  #4       arena_list:OK
  #434/1   verifier_arena/basic_alloc1:OK
  #434/2   verifier_arena/basic_alloc2:OK
  #434/3   verifier_arena/basic_alloc3:OK
  #434/4   verifier_arena/iter_maps1:OK
  #434/5   verifier_arena/iter_maps2:OK
  #434/6   verifier_arena/iter_maps3:OK
  #434     verifier_arena:OK
  Summary: 3/10 PASSED, 0 SKIPPED, 0 FAILED

The implementation of bpf_addr_space_cast can be optimised by using ROR
(immediate) and CSEL instructions. Currently, lib/insn.c doesn't have APIs
to generate these intructions. I will send subsequent patches to implement
the APIs and then use these instructions in the JIT.

Puranjay Mohan (2):
  bpf: Add arm64 JIT support for PROBE_MEM32 pseudo instructions.
  bpf: Add arm64 JIT support for bpf_addr_space_cast instruction.

 arch/arm64/net/bpf_jit.h                     |   1 +
 arch/arm64/net/bpf_jit_comp.c                | 105 +++++++++++++++++--
 tools/testing/selftests/bpf/DENYLIST.aarch64 |   2 -
 3 files changed, 96 insertions(+), 12 deletions(-)