[PATCH bpf-next v4 3/3] selftests/bpf: Enable stack argument tests for RV64

[Pu Lehui]

On 2026/9/5 15:45, bot+bpf-ci at kernel.org wrote:
>> Enable the stack argument selftests for RV64. The riscv guard is
>> restricted to __riscv_xlen == 64 since stack arguments are only
>> supported by the RV64 JIT.
>>
>> Keep the __BPF_FEATURE_STACK_ARGUMENT gate, defined by clang with
>> BPF stack argument support [1].
>>
>> [1] https://github.com/llvm/llvm-project/pull/189060
>>
>> Signed-off-by: Feng Jiang <jiangfeng at kylinos.cn>
> 
> The changelog says "Enable the stack argument selftests for RV64", but
> one arch-gated stack-argument test remains on x86_64/arm64 only.
> 
> Exhaustive list of every arch-gated stack-argument test in
> tools/testing/selftests/bpf:
> 
>    progs/btf__stack_arg_precision.c        updated by this patch
>    progs/btf__verifier_stack_arg_order.c   updated by this patch
>    progs/stack_arg.c                       updated by this patch
>    progs/stack_arg_kfunc.c                 updated by this patch
>    progs/stack_arg_precision.c             updated by this patch
>    progs/verifier_stack_arg.c              updated by this patch
>    progs/verifier_stack_arg_order.c        updated by this patch
>    progs/stack_arg_fail.c                  no arch gate - already runs
>    progs/exceptions.c:383                  intentionally left alone
>    progs/arena_kfunc.c:219-230             not updated, not explained
> 
> progs/exceptions.c is correctly left alone: DENYLIST.riscv64 lists
> 'exceptions' with the comment "JIT does not support exceptions", and
> arch/riscv/net/ implements no bpf_jit_supports_exceptions().
> 
> progs/arena_kfunc.c is not explained. It gates its stack-argument test
> with test_loader arch annotations rather than a preprocessor guard:
> 
>    #if defined(__BPF_FEATURE_ADDR_SPACE_CAST) && \
>            defined(__BPF_FEATURE_STACK_ARGUMENT)
>    SEC("syscall")
>    __arch_x86_64
>    __arch_arm64
>    __failure __msg("arena pointer cannot be a stack argument")
>    int arena_arg_stack(void *ctx)
> 
> test_loader.c skips any test whose arch mask does not contain the running
> arch, so arena_arg_stack stays skipped on RV64 after this patch.
> 
> Does anything block it from running on RV64?  bpf_jit_supports_arena()
> returns true on riscv64, DENYLIST.riscv64 contains only 'exceptions', and
> arena_arg_stack is a __failure test so it only needs the verifier to reach
> the "arena pointer cannot be a stack argument" check - which now happens
> on RV64 because the preceding commit makes bpf_jit_supports_stack_args()
> return true.
> 
> Should __arch_riscv64 be added to progs/arena_kfunc.c's arena_arg_stack
> (and the #else dummy_test, which carries the same two annotations), or is
> there a reason it should stay on x86_64/arm64 only?

not yet support bpf_jit_supports_arena_args and Kumar have been worked 
on this [0].

[0] https://lore.kernel.org/bpf/20260821233516.3426127-4-memxor@gmail.com/

> 
> 
> ---
> AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
> See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
> 
> CI run summary: https://github.com/kernel-patches/bpf/actions/runs/33952202002