On Tue, Apr 2, 2024 at 3:50 PM Andrii Nakryiko <andrii@xxxxxxxxxx> wrote:
>
> Add selftests validating that BPF verifier handles precision marking
> for SCALAR registers derived from r10 (fp) register correctly.
>
> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> ---
> .../bpf/progs/verifier_subprog_precision.c | 86 +++++++++++++++++++
> 1 file changed, 86 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c b/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c
> index 6f5d19665cf6..e1a8f107f0a7 100644
> --- a/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c
> +++ b/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c
> @@ -76,6 +76,92 @@ __naked int subprog_result_precise(void)
> );
> }
>
> +__naked __noinline __used
> +static unsigned long fp_leaking_subprog()
> +{
> + asm volatile (
> + "r0 = (s8)r10;"
Our CI's clang doesn't like this instruction. I guess I'll have to
encode it in binary form :(
> + "exit;"
> + );
> +}
> +
[...]
