S390: Influence hwcaps/stfle via GLIBC_TUNABLES.

This patch enables the option to influence hwcaps and stfle bits used
by the s390 specific ifunc-resolvers.  The currently x86-specific
tunable glibc.cpu.hwcaps is also used on s390x to achieve the task. In
addition the user can also set a CPU arch-level like z13 instead of
single HWCAP and STFLE features.

Note that the tunable only handles the features which are really used
in the IFUNC-resolvers.  All others are ignored as the values are only
used inside glibc.  Thus we can influence:
- HWCAP_S390_VXRS (z13)
- HWCAP_S390_VXRS_EXT (z14)
- HWCAP_S390_VXRS_EXT2 (z15)
- STFLE_MIE3 (z15)

The influenced hwcap/stfle-bits are stored in the s390-specific
cpu_features struct which also contains reserved fields for future
usage.

The ifunc-resolvers and users of stfle bits are adjusted to use the
information from cpu_features struct.

On 31bit, the ELF_MACHINE_IRELATIVE macro is now also defined.
Otherwise the new ifunc-resolvers segfaults as they depend on
the not yet processed_rtld_global_ro@GLIBC_PRIVATE relocation.

0 files changed, 0 insertions, 0 deletions