[v2] s390: Move hwcaps/platform names out of _rtld_global_ro

  Changes to these arrays are often backported to stable releases,
but additions to these arrays shift the offsets of the following
_rltd_global_ro members, thus breaking the GLIBC_PRIVATE ABI.

Obviously, this change is itself an internal ABI break, but at least
it will avoid further ABI breaks going forward.

---
v2: Use more macro constants, fix typos.  (Tests still running.)
 sysdeps/s390/Makefile                      |  2 +
 sysdeps/s390/dl-procinfo-s390.c            | 32 +++++++++++++++
 sysdeps/s390/dl-procinfo.c                 | 64 ++----------------------------
 sysdeps/s390/dl-procinfo.h                 |  8 ++--
 sysdeps/unix/sysv/linux/s390/dl-procinfo.h |  2 +-
 5 files changed, 44 insertions(+), 64 deletions(-)


base-commit: 89baed0b93639180fd7d0ba922873b003649c7af
  

On 8/25/22 15:19, Florian Weimer wrote:
> Changes to these arrays are often backported to stable releases,
> but additions to these arrays shift the offsets of the following
> _rltd_global_ro members, thus breaking the GLIBC_PRIVATE ABI.
> 
> Obviously, this change is itself an internal ABI break, but at least
> it will avoid further ABI breaks going forward.

LGTM.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
 
> ---
> v2: Use more macro constants, fix typos.  (Tests still running.)
>  sysdeps/s390/Makefile                      |  2 +
>  sysdeps/s390/dl-procinfo-s390.c            | 32 +++++++++++++++
>  sysdeps/s390/dl-procinfo.c                 | 64 ++----------------------------
>  sysdeps/s390/dl-procinfo.h                 |  8 ++--
>  sysdeps/unix/sysv/linux/s390/dl-procinfo.h |  2 +-
>  5 files changed, 44 insertions(+), 64 deletions(-)
> 
> diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
> index 5b6a96579c..1d687a2184 100644
> --- a/sysdeps/s390/Makefile
> +++ b/sysdeps/s390/Makefile
> @@ -43,6 +43,8 @@ $(modpfx)gconv-modules-s390.conf: ../sysdeps/s390/gconv-modules-s390.conf \
>  endif
>  
>  ifeq ($(subdir),elf)
> +sysdep-dl-routines += dl-procinfo-s390
> +
>  ifeq ($(build-shared),yes)
>  tests += tst-dl-runtime-resolve-noaudit tst-dl-runtime-resolve-audit \
>  	tst-dl-runtime-profile-noaudit
> diff --git a/sysdeps/s390/dl-procinfo-s390.c b/sysdeps/s390/dl-procinfo-s390.c
> new file mode 100644
> index 0000000000..559f382793
> --- /dev/null
> +++ b/sysdeps/s390/dl-procinfo-s390.c
> @@ -0,0 +1,32 @@
> +/* Data for s390 version of processor capability information.
> +   Copyright (C) 2006-2022 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/>.  */
> +
> +#include <dl-procinfo.h>
> +
> +const char _dl_s390_cap_flags[_DL_HWCAP_COUNT][9] =
> +  {
> +    "esan3", "zarch", "stfle", "msa", "ldisp", "eimm", "dfp", "edat", "etf3eh",
> +    "highgprs", "te", "vx", "vxd", "vxe", "gs", "vxe2", "vxp", "sort", "dflt",
> +    "vxp2", "nnpa", "pcimio", "sie"
> +  };
> +
> +const char _dl_s390_platforms[_DL_PLATFORMS_COUNT][7] =
> +  {
> +    "g5", "z900", "z990", "z9-109", "z10", "z196", "zEC12", "z13", "z14", "z15",
> +    "z16"
> +  };

OK. Perfect.

> diff --git a/sysdeps/s390/dl-procinfo.c b/sysdeps/s390/dl-procinfo.c
> index f142221a17..88c955c12b 100644
> --- a/sysdeps/s390/dl-procinfo.c
> +++ b/sysdeps/s390/dl-procinfo.c
> @@ -16,66 +16,10 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>  
> -/* This information must be kept in sync with the _DL_HWCAP_COUNT and
> -   _DL_PLATFORM_COUNT definitions in procinfo.h.
> -
> -   If anything should be added here check whether the size of each string
> -   is still ok with the given array size.
> -
> -   All the #ifdefs in the definitions are quite irritating but
> -   necessary if we want to avoid duplicating the information.  There
> -   are three different modes:
> -
> -   - PROCINFO_DECL is defined.  This means we are only interested in
> -     declarations.
> -
> -   - PROCINFO_DECL is not defined:
> -
> -     + if SHARED is defined the file is included in an array
> -       initializer.  The .element = { ... } syntax is needed.
> -
> -     + if SHARED is not defined a normal array initialization is
> -       needed.
> -  */
> -
> -#ifndef PROCINFO_CLASS
> -# define PROCINFO_CLASS
> -#endif
> -
> -#if !defined PROCINFO_DECL && defined SHARED
> -  ._dl_s390_cap_flags
> -#else
> -PROCINFO_CLASS const char _dl_s390_cap_flags[23][9]
> -#endif
> -#ifndef PROCINFO_DECL
> -= {
> -     "esan3", "zarch", "stfle", "msa", "ldisp", "eimm", "dfp", "edat", "etf3eh",
> -     "highgprs", "te", "vx", "vxd", "vxe", "gs", "vxe2", "vxp", "sort", "dflt",
> -     "vxp2", "nnpa", "pcimio", "sie"
> -  }
> -#endif
> -#if !defined SHARED || defined PROCINFO_DECL
> -;
> -#else
> -,
> -#endif
> -
> -#if !defined PROCINFO_DECL && defined SHARED
> -  ._dl_s390_platforms
> -#else
> -PROCINFO_CLASS const char _dl_s390_platforms[11][7]
> -#endif
> -#ifndef PROCINFO_DECL
> -= {
> -    "g5", "z900", "z990", "z9-109", "z10", "z196", "zEC12", "z13", "z14", "z15",
> -    "z16"
> -  }
> -#endif
> -#if !defined SHARED || defined PROCINFO_DECL
> -;
> -#else
> -,
> -#endif
> +/* The hwcap and platform strings are now in
> +   sysdeps/s390/dl-procinfo-s390.c.  */

OK. Great comment.

>  
> +/* Needed by sysdeps/unix/sysv/linux/dl-vdso-setup.c (as included from
> +   sysdeps/generic/ldsodefs.h).  */
>  #undef PROCINFO_DECL
>  #undef PROCINFO_CLASS
> diff --git a/sysdeps/s390/dl-procinfo.h b/sysdeps/s390/dl-procinfo.h
> index 1f4e3875ba..e1f88b9ab7 100644
> --- a/sysdeps/s390/dl-procinfo.h
> +++ b/sysdeps/s390/dl-procinfo.h
> @@ -21,8 +21,10 @@
>  #include <ldsodefs.h>
>  
>  #define _DL_HWCAP_COUNT 23
> +extern const char _dl_s390_cap_flags[_DL_HWCAP_COUNT][9] attribute_hidden;
>  
>  #define _DL_PLATFORMS_COUNT	11
> +extern const char _dl_s390_platforms[_DL_PLATFORMS_COUNT][7] attribute_hidden;

OK.

>  
>  /* The kernel provides up to 32 capability bits with elf_hwcap.  */
>  #define _DL_FIRST_PLATFORM	32
> @@ -78,7 +80,7 @@ static inline const char *
>  __attribute__ ((unused))
>  _dl_hwcap_string (int idx)
>  {
> -  return GLRO(dl_s390_cap_flags)[idx];
> +  return _dl_s390_cap_flags[idx];
>  };
>  
>  static inline int
> @@ -89,7 +91,7 @@ _dl_string_hwcap (const char *str)
>  
>    for (i = 0; i < _DL_HWCAP_COUNT; i++)
>      {
> -      if (strcmp (str, GLRO(dl_s390_cap_flags)[i]) == 0)
> +      if (strcmp (str, _dl_s390_cap_flags[i]) == 0)
>  	return i;
>      }
>    return -1;
> @@ -104,7 +106,7 @@ _dl_string_platform (const char *str)
>    if (str != NULL)
>      for (i = 0; i < _DL_PLATFORMS_COUNT; ++i)
>        {
> -	if (strcmp (str, GLRO(dl_s390_platforms)[i]) == 0)
> +	if (strcmp (str, _dl_s390_platforms[i]) == 0)
>  	  return _DL_FIRST_PLATFORM + i;
>        }
>    return -1;
> diff --git a/sysdeps/unix/sysv/linux/s390/dl-procinfo.h b/sysdeps/unix/sysv/linux/s390/dl-procinfo.h
> index 46790c2103..a8e27149fd 100644
> --- a/sysdeps/unix/sysv/linux/s390/dl-procinfo.h
> +++ b/sysdeps/unix/sysv/linux/s390/dl-procinfo.h
> @@ -39,7 +39,7 @@ _dl_procinfo (unsigned int type, unsigned long int word)
>  
>    for (i = 0; i < _DL_HWCAP_COUNT; ++i)
>      if (word & (1UL << i))
> -      _dl_printf (" %s", GLRO(dl_s390_cap_flags)[i]);
> +      _dl_printf (" %s", _dl_s390_cap_flags[i]);
>  
>    _dl_printf ("\n");
>  
> 
> base-commit: 89baed0b93639180fd7d0ba922873b003649c7af
>