[bpf-next 0/6] bpf,powerpc: Add support for bpf arena and arena atomics

[Venkat Rao Bagalkote]

On 05/08/25 11:57 am, Saket Kumar Bhaskar wrote:
> This patch series introduces support for the PROBE_MEM32,
> bpf_addr_space_cast and PROBE_ATOMIC instructions in the powerpc BPF JIT,
> facilitating the implementation of BPF arena and arena atomics.
>
> The last patch in the series has fix for arena spinlock selftest
> failure.
>
> This series is rebased on top of:
> https://lore.kernel.org/bpf/20250717202935.29018-2-puranjay@kernel.org/
>
> All selftests related to bpf_arena, bpf_arena_atomic(except
> load_acquire/store_release) enablement are passing:


Hello Saket,


I see couple of selftests are failing on my set up.

>
> # ./test_progs -t arena_list
> #5/1     arena_list/arena_list_1:OK
> #5/2     arena_list/arena_list_1000:OK
> #5       arena_list:OK
> Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
>
> # ./test_progs -t arena_htab
> #4/1     arena_htab/arena_htab_llvm:OK
> #4/2     arena_htab/arena_htab_asm:OK
> #4       arena_htab:OK
> Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
>
> # ./test_progs -t verifier_arena
> #464/1   verifier_arena/basic_alloc1:OK
> #464/2   verifier_arena/basic_alloc2:OK
> #464/3   verifier_arena/basic_alloc3:OK
> #464/4   verifier_arena/iter_maps1:OK
> #464/5   verifier_arena/iter_maps2:OK
> #464/6   verifier_arena/iter_maps3:OK
> #464     verifier_arena:OK
> #465/1   verifier_arena_large/big_alloc1:OK
> #465/2   verifier_arena_large/big_alloc2:OK
> #465     verifier_arena_large:OK
> Summary: 2/8 PASSED, 0 SKIPPED, 0 FAILED


All error logs:
tester_init:PASS:tester_log_buf 0 nsec
process_subtest:PASS:obj_open_mem 0 nsec
process_subtest:PASS:specs_alloc 0 nsec
run_subtest:PASS:obj_open_mem 0 nsec
run_subtest:PASS:unexpected_load_failure 0 nsec
do_prog_test_run:PASS:bpf_prog_test_run 0 nsec
run_subtest:FAIL:1103 Unexpected retval: 4 != 0
#513/7   verifier_arena/reserve_invalid_region:FAIL
#513     verifier_arena:FAIL
Summary: 1/14 PASSED, 0 SKIPPED, 1 FAILED


>
> # ./test_progs -t arena_atomics
> #3/1     arena_atomics/add:OK
> #3/2     arena_atomics/sub:OK
> #3/3     arena_atomics/and:OK
> #3/4     arena_atomics/or:OK
> #3/5     arena_atomics/xor:OK
> #3/6     arena_atomics/cmpxchg:OK
> #3/7     arena_atomics/xchg:OK
> #3/8     arena_atomics/uaf:OK
> #3/9     arena_atomics/load_acquire:SKIP
> #3/10    arena_atomics/store_release:SKIP
> #3       arena_atomics:OK (SKIP: 2/10)
> Summary: 1/8 PASSED, 2 SKIPPED, 0 FAILED
>
> All selftests related to arena_spin_lock are passing:
>
> # ./test_progs -t arena_spin_lock
> #6/1     arena_spin_lock/arena_spin_lock_1:OK
> #6/2     arena_spin_lock/arena_spin_lock_1000:OK
> #6/3     arena_spin_lock/arena_spin_lock_50000:OK
> #6       arena_spin_lock:OK
> Summary: 1/3 PASSED, 0 SKIPPED, 0 FAILED
test_arena_spin_lock_size:FAIL:check counter value unexpected check 
counter value: actual 15999 != expected 16000
#6/1     arena_spin_lock/arena_spin_lock_1:FAIL
#6       arena_spin_lock:FAIL
Summary: 0/2 PASSED, 0 SKIPPED, 1 FAILED
> Saket Kumar Bhaskar (6):
>    bpf,powerpc: Introduce bpf_jit_emit_probe_mem_store() to emit store
>      instructions
>    bpf,powerpc: Implement PROBE_MEM32 pseudo instructions
>    bpf,powerpc: Implement bpf_addr_space_cast instruction
>    bpf,powerpc: Introduce bpf_jit_emit_atomic_ops() to emit atomic
>      instructions
>    bpf,powerpc: Implement PROBE_ATOMIC instructions
>    selftests/bpf: Fix arena_spin_lock selftest failure
>
>   arch/powerpc/net/bpf_jit.h                    |   6 +-
>   arch/powerpc/net/bpf_jit_comp.c               |  32 +-
>   arch/powerpc/net/bpf_jit_comp32.c             |   2 +-
>   arch/powerpc/net/bpf_jit_comp64.c             | 378 +++++++++++++-----
>   .../bpf/prog_tests/arena_spin_lock.c          |  23 +-
>   .../selftests/bpf/progs/arena_spin_lock.c     |   8 +-
>   .../selftests/bpf/progs/bpf_arena_spin_lock.h |   4 +-
>   7 files changed, 348 insertions(+), 105 deletions(-)
>
> base-commit: ea2aecdf7a954a8c0015e185cc870c4191d1d93f


Regards,

Venkat.