Re: [gold patch] PR 22969: Add support for R_AARCH64_TLSLE_LDST8_TPREL_LO12, etc.

[Renlin Li <renlin dot li at foss dot arm dot com>]

Hi Cary,

On 28/03/18 02:23, Cary Coutant wrote:
> > Can you please look over this patch and give it a test? Let me know if
> > it's OK to check in.
>
> While I was looking in relocate_tls(), I found the following, which
> looks suspicious to me:
>
>      case elfcpp::R_AARCH64_TLSLE_MOVW_TPREL_G2:
>      case elfcpp::R_AARCH64_TLSLE_MOVW_TPREL_G1:
>      case elfcpp::R_AARCH64_TLSLE_MOVW_TPREL_G1_NC:
>      case elfcpp::R_AARCH64_TLSLE_MOVW_TPREL_G0:
>      case elfcpp::R_AARCH64_TLSLE_MOVW_TPREL_G0_NC:
>      case elfcpp::R_AARCH64_TLSLE_ADD_TPREL_HI12:
>      case elfcpp::R_AARCH64_TLSLE_ADD_TPREL_LO12:
>      case elfcpp::R_AARCH64_TLSLE_ADD_TPREL_LO12_NC:
>        {
>          gold_assert(tls_segment != NULL);
>          AArch64_address value = psymval->value(object, 0);
>
>          if (!parameters->options().shared())
>            {
>              AArch64_address aligned_tcb_size =
>                  align_address(target->tcb_size(),
>                                tls_segment->maximum_alignment());
>              value += aligned_tcb_size;
>              switch (r_type)
>                {
>                case elfcpp::R_AARCH64_TLSLE_MOVW_TPREL_G2:
>                case elfcpp::R_AARCH64_TLSLE_MOVW_TPREL_G1:
>                case elfcpp::R_AARCH64_TLSLE_MOVW_TPREL_G0:
>                  return aarch64_reloc_funcs::movnz(view, value + addend,
>                                                    reloc_property);
>                default:
>                  return aarch64_reloc_funcs::template
>                    rela_general<32>(view,
>                                     value,
>                                     addend,
>                                     reloc_property);
>                }
>            }
>
> For TLSLE_MOVW_TPREL_G1_NC and TLSLE_MOVW_TPREL_G0_NC, shouldn't we
> also use movnz instead of the default rela_general?

This is correct as far as I know.

TLSLE_MOVW_TPREL_G1_NC, TLSLE_MOVW_TPREL_G0_NC are relocations used with MOVK instruction.
while
TLSLE_MOVW_TPREL_G2, TLSLE_MOVW_TPREL_G1, TLSLE_MOVW_TPREL_G0 are used with MOV[NZ] instruction.

Regards,
Renlin

> -cary