glibc/sysdeps/s390/cpu-features.h
Stefan Liebler 41f67ccbe9 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.
2023-02-07 09:19:27 +01:00

47 lines
1.7 KiB
C

/* Initialize cpu feature data. s390x version.
Copyright (C) 2023 Free Software Foundation, Inc.
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/>. */
#ifndef __CPU_FEATURES_S390X_H
# define __CPU_FEATURES_S390X_H
#define S390_STFLE_BITS_Z10 34 /* General instructions extension */
#define S390_STFLE_BITS_Z196 45 /* Distinct operands, pop ... */
#define S390_STFLE_BITS_ARCH13_MIE3 61 /* Miscellaneous-Instruction-Extensions
Facility 3, e.g. mvcrl. */
#define S390_STFLE_MASK_ARCH13_MIE3 (1ULL << (63 - S390_STFLE_BITS_ARCH13_MIE3))
#define S390_IS_ARCH13_MIE3(STFLE_BITS_ARRAY) \
(((STFLE_BITS_ARRAY)[0] & S390_STFLE_MASK_ARCH13_MIE3) != 0)
#define S390_IS_Z196(STFLE_BITS_ARRAY) \
(((STFLE_BITS_ARRAY)[0] & (1ULL << (63 - S390_STFLE_BITS_Z196))) != 0)
#define S390_IS_Z10(STFLE_BITS_ARRAY) \
(((STFLE_BITS_ARRAY)[0] & (1ULL << (63 - S390_STFLE_BITS_Z10))) != 0)
struct cpu_features
{
unsigned long int hwcap;
unsigned long int __reserved_hwcap2;
unsigned long long stfle_bits[3];
unsigned long long __reserved[11];
};
#endif /* __CPU_FEATURES_S390X_H */