Re: [PATCH bpf-next v1 1/7] selftests/bpf: Build callx tests with GCC that defines __BPF_FEATURE_CALLX

[Vineet Gupta]

On 10/27/26 5:46 PM, bot+bpf-ci@xxxxxxxxxx wrote:
> > selftests/bpf: Build callx tests with GCC that defines __BPF_FEATURE_CALLX
> TL;DR: Nit only: the new __skip() reason in the callx selftests omits riscv64,
> though riscv64 is supported, so a riscv64 build with a GCC lacking callx
> prints a misleading skip message.
>
> > +/* clang always emits callx, gcc only when it defines __BPF_FEATURE_CALLX */
> > +#if (defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_x86) ||	\
> > +     (defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64)) &&		\
> > +	(defined(__clang__) || defined(__BPF_FEATURE_CALLX))
> > +#define CAN_USE_CALLX
> > +#endif
> > +
> > @@ -1075,6 +1073,7 @@ int callx_c_ops_on_stack(void *ctx)
> >   #else
> >
> >   SEC("socket")
> > +__skip("callx needs x86/arm64 JIT and compiler support")
> >   __success
> >   int dummy(void *ctx)
> >   {
> this isn't a bug, but the skip reason leaves out riscv64, even though the
> CAN_USE_CALLX macro above accepts it.
>
> The same string is added to the dummy() program in
> verifier_callx_rodata.c.  The riscv64 JIT implements bpf_jit_supports_callx(),
> and commit 530dfafc6107 ("selftests/bpf: Enable callx related testcases for
> RV64") turned these tests on for RV64.
>
> On a riscv64 build with a bpf-gcc that does not define __BPF_FEATURE_CALLX,
> the arch supports callx and only the compiler lacks it, yet run_subtest()
> prints:
>
>    run_subtest:SKIP: callx needs x86/arm64 JIT and compiler support
>
> That reads as though riscv64 itself were unsupported.
>
> Could the reason say x86/arm64/riscv64, or leave the arch list out (for
> example "toolchain or JIT can't do callx", as the new comment in
> callx_rodata_lskel.c does)?

I'll just leave out the arch list and refer to just toolchain or JIT.

Thx,
-Vineet

> ---
> 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/40608355234