[PATCH v2 2/2] ARC/dl-runtime helper macros

[Adhemerval Zanella]

On 01/06/2020 19:18, Vineet Gupta wrote:
> This is purely for review purposes to attest the interface defined
> in prior patch

LGTM with some style nits, however I think it should be pushed along with 
the ARC patchset.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

> ---
>  sysdeps/arc/dl-runtime.h | 42 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
>  create mode 100644 sysdeps/arc/dl-runtime.h
> 
> diff --git a/sysdeps/arc/dl-runtime.h b/sysdeps/arc/dl-runtime.h
> new file mode 100644
> index 000000000000..529d49f5d0a1
> --- /dev/null
> +++ b/sysdeps/arc/dl-runtime.h
> @@ -0,0 +1,42 @@
> +/* Helpers for On-demand PLT fixup for shared objects. ARC version.

Double space after period.

> +   Copyright (C) 2017-2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public License as
> +   published by the Free Software Foundation; either version 2.1 of the
> +   License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library.  If not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +/* PLT jump into resolver passes PC of PLTn, while _dl_fixup expects the
> +   address of corresponding .rela.plt entry.
> +
> +    - @plt0: runtime pc of first plt entry (DT_PLTGOT)
> +    - @pltn: runtime pc of plt entry being resolved
> +    - @size: size of .plt.rela entry (unused).  */
> +static inline uintptr_t
> +reloc_index (uintptr_t plt0, uintptr_t pltn, size_t size)
> +{
> +  unsigned long int idx = (unsigned long)pltn - (unsigned long)plt0;

I don't think the explicit cast is required here.

> +
> +  /* PLT trampoline is 16 bytes. */
> +  idx /= 16;
> +
> +  /* Exclude PLT0 and PLT1.  */
> +  return idx - 2;
> +}
> +
> +static inline uintptr_t
> +reloc_offset (uintptr_t plt0, uintptr_t pltn)
> +{
> +  size_t sz = sizeof (ElfW(Rela));
> +  return reloc_index(plt0, pltn, sz) * sz;

Space before parenthesis.

> +}
>