Re: [PATCH bpf-next 2/2] selftests/bpf: Extend live regs tests with a test for gotox

[Anton Protopopov <a.s.protopopov@gmail.com>]

On 26/01/14 11:33AM, Anton Protopopov wrote:
> Add a test which checks that the destination register of a gotox
> instruction is marked as used and that the union of jump targets
> is considered as live.
> 
> Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
> ---
>  .../bpf/progs/compute_live_registers.c        | 37 +++++++++++++++++++
>  1 file changed, 37 insertions(+)
> 
> diff --git a/tools/testing/selftests/bpf/progs/compute_live_registers.c b/tools/testing/selftests/bpf/progs/compute_live_registers.c
> index 6884ab99a421..fad91c599095 100644
> --- a/tools/testing/selftests/bpf/progs/compute_live_registers.c
> +++ b/tools/testing/selftests/bpf/progs/compute_live_registers.c
> @@ -431,6 +431,43 @@ __naked void subprog1(void)
>  		::: __clobber_all);
>  }
>  
> +SEC("socket")
> +__log_level(2)
> +__msg("2: .1........ (07) r1 += 8")
> +__msg("3: .1........ (79) r2 = *(u64 *)(r1 +0)")
> +__msg("4: ..2....... (b7) r3 = 1")
> +__msg("5: ..23...... (b7) r4 = 2")
> +__msg("6: ..234..... (0d) gotox r2")
> +__msg("7: ...3...... (bf) r0 = r3")
> +__msg("8: 0......... (95) exit")
> +__msg("9: ....4..... (bf) r0 = r4")
> +__msg("10: 0......... (95) exit")
> +__naked
> +void gotox(void)
> +{
> +	asm volatile (
> +	".pushsection .jumptables,\"\",@progbits;"
> +"jt0_%=: .quad l0_%= - socket;"
> +	".quad l1_%= - socket;"
> +	".size jt0_%=, 16;"
> +	".global jt0_%=;"
> +	".popsection;"
> +
> +	"r1 = jt0_%= ll;"
> +	"r1 += 8;"
> +	"r2 = *(u64 *)(r1 + 0);"
> +	"r3 = 1;"
> +	"r4 = 2;"
> +	".8byte %[gotox_r2];"
> +"l0_%=:  r0 = r3;"
> +	"exit;"
> +"l1_%=:  r0 = r4;"
> +	"exit;"
> +	:
> +	: __imm_insn(gotox_r2, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_2, BPF_REG_0, 0, 0))
> +	: __clobber_all);
> +}
> +
>  /* to retain debug info for BTF generation */
>  void kfunc_root(void)
>  {
> -- 
> 2.34.1
> 

Ah, this fails on s390x. I will send a fix later today.