[PATCH bpf-next 0/8] bpf, riscv64: Support load-acquire and store-release instructions

[Pu Lehui]

On 2025/4/30 8:48, Peilin Ye wrote:
> Hi all!
> 
> Patchset [1] introduced BPF load-acquire (BPF_LOAD_ACQ) and
> store-release (BPF_STORE_REL) instructions, and added x86-64 and arm64
> JIT compiler support.  As a follow-up, this patchset supports
> load-acquire and store-release instructions for the riscv64 JIT
> compiler, and introduces some related selftests/ changes.
> 
> Specifically:
> 
>   * PATCH 1 makes insn_def_regno() handle load-acquires properly for
>     bpf_jit_needs_zext() (true for riscv64) architectures
>   * PATCH 2, 3 from Andrea Parri add the actual support to the riscv64
>     JIT compiler
>   * PATCH 4 optimizes code emission by skipping redundant zext
>     instructions inserted by the verifier
>   * PATCH 5, 6 and 7 are minor selftest/ improvements
>   * PATCH 8 enables (non-arena) load-acquire/store-release selftests for
>     riscv64
> 
> Please refer to individual patches for details.  Thanks!
> 
> [1] https://lore.kernel.org/all/cover.1741049567.git.yepeilin@google.com/
> 
> Andrea Parri (2):
>    bpf, riscv64: Introduce emit_load_*() and emit_store_*()
>    bpf, riscv64: Support load-acquire and store-release instructions
> 
> Peilin Ye (6):
>    bpf/verifier: Handle BPF_LOAD_ACQ instructions in insn_def_regno()
>    bpf, riscv64: Skip redundant zext instruction after load-acquire
>    selftests/bpf: Use CAN_USE_LOAD_ACQ_STORE_REL when appropriate
>    selftests/bpf: Avoid passing out-of-range values to __retval()
>    selftests/bpf: Verify zero-extension behavior in load-acquire tests
>    selftests/bpf: Enable non-arena load-acquire/store-release selftests
>      for riscv64
> 
>   arch/riscv/net/bpf_jit.h                      |  15 +
>   arch/riscv/net/bpf_jit_comp64.c               | 334 ++++++++++++------
>   arch/riscv/net/bpf_jit_core.c                 |   3 +-
>   kernel/bpf/verifier.c                         |  11 +-
>   tools/testing/selftests/bpf/progs/bpf_misc.h  |   5 +-
>   .../bpf/progs/verifier_load_acquire.c         |  48 ++-
>   .../selftests/bpf/progs/verifier_precision.c  |   5 +-
>   .../bpf/progs/verifier_store_release.c        |  39 +-
>   8 files changed, 314 insertions(+), 146 deletions(-)
> 

Hi Peilin, good to see the implementation of load-acquire and 
store-release instructions on RV64! But I'm about to start my vacation, 
so I'll test it once I'm back.