PowerPC: Influence cpu/arch hwcap features via GLIBC_TUNABLES

This patch enables the option to influence hwcaps used by PowerPC.
The environment variable, GLIBC_TUNABLES=glibc.cpu.hwcaps=-xxx,yyy,-zzz....,
can be used to enable CPU/ARCH feature yyy, disable CPU/ARCH feature xxx
and zzz, where the feature name is case-sensitive and has to match the ones
mentioned in the file{sysdeps/powerpc/dl-procinfo.c}.

Note that the hwcap tunables only used in the IFUNC selection.
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 130 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/powerpc/cpu-features.h b/sysdeps/unix/sysv/linux/powerpc/cpu-features.h
new file mode 100644
index 0000000000..e5fce88e5e
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/powerpc/cpu-features.h
@@ -0,0 +1,130 @@
+/* Initialize cpu feature data.  PowerPC version.
+   Copyright (C) 2017-2023 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_POWERPC_H
+# define __CPU_FEATURES_POWERPC_H
+
+#include <stdbool.h>
+#include <sys/auxv.h>
+
+struct cpu_features
+{
+  bool use_cached_memopt;
+  unsigned long int hwcap;
+  unsigned long int hwcap2;
+};
+
+static const char hwcap_names[] = {
+  "4xxmac\0"
+  "altivec\0"
+  "arch_2_05\0"
+  "arch_2_06\0"
+  "archpmu\0"
+  "booke\0"
+  "cellbe\0"
+  "dfp\0"
+  "efpdouble\0"
+  "efpsingle\0"
+  "fpu\0"
+  "ic_snoop\0"
+  "mmu\0"
+  "notb\0"
+  "pa6t\0"
+  "power4\0"
+  "power5\0"
+  "power5+\0"
+  "power6x\0"
+  "ppc32\0"
+  "ppc601\0"
+  "ppc64\0"
+  "ppcle\0"
+  "smt\0"
+  "spe\0"
+  "true_le\0"
+  "ucache\0"
+  "vsx\0"
+  "arch_2_07\0"
+  "dscr\0"
+  "ebb\0"
+  "htm\0"
+  "htm-nosc\0"
+  "htm-no-suspend\0"
+  "isel\0"
+  "tar\0"
+  "vcrypto\0"
+  "arch_3_00\0"
+  "ieee128\0"
+  "darn\0"
+  "scv\0"
+  "arch_3_1\0"
+  "mma\0"
+};
+
+static const struct
+{
+  unsigned int mask;
+  bool id;
+} hwcap_tunables[] = {
+   /* AT_HWCAP tunable masks.  */
+   { PPC_FEATURE_HAS_4xxMAC,                 0 },
+   { PPC_FEATURE_HAS_ALTIVEC,                0 },
+   { PPC_FEATURE_ARCH_2_05,                  0 },
+   { PPC_FEATURE_ARCH_2_06,                  0 },
+   { PPC_FEATURE_PSERIES_PERFMON_COMPAT,     0 },
+   { PPC_FEATURE_BOOKE,                      0 },
+   { PPC_FEATURE_CELL_BE,                    0 },
+   { PPC_FEATURE_HAS_DFP,                    0 },
+   { PPC_FEATURE_HAS_EFP_DOUBLE,             0 },
+   { PPC_FEATURE_HAS_EFP_SINGLE,             0 },
+   { PPC_FEATURE_HAS_FPU,                    0 },
+   { PPC_FEATURE_ICACHE_SNOOP,               0 },
+   { PPC_FEATURE_HAS_MMU,                    0 },
+   { PPC_FEATURE_NO_TB,                      0 },
+   { PPC_FEATURE_PA6T,                       0 },
+   { PPC_FEATURE_POWER4,                     0 },
+   { PPC_FEATURE_POWER5,                     0 },
+   { PPC_FEATURE_POWER5_PLUS,                0 },
+   { PPC_FEATURE_POWER6_EXT,                 0 },
+   { PPC_FEATURE_32,                         0 },
+   { PPC_FEATURE_601_INSTR,                  0 },
+   { PPC_FEATURE_64,                         0 },
+   { PPC_FEATURE_PPC_LE,                     0 },
+   { PPC_FEATURE_SMT,                        0 },
+   { PPC_FEATURE_HAS_SPE,                    0 },
+   { PPC_FEATURE_TRUE_LE,                    0 },
+   { PPC_FEATURE_UNIFIED_CACHE,              0 },
+   { PPC_FEATURE_HAS_VSX,                    0 },
+
+   /* AT_HWCAP2 tunable masks.  */
+   { PPC_FEATURE2_ARCH_2_07,                 1 },
+   { PPC_FEATURE2_HAS_DSCR,                  1 },
+   { PPC_FEATURE2_HAS_EBB,                   1 },
+   { PPC_FEATURE2_HAS_HTM,                   1 },
+   { PPC_FEATURE2_HTM_NOSC,                  1 },
+   { PPC_FEATURE2_HTM_NO_SUSPEND,            1 },
+   { PPC_FEATURE2_HAS_ISEL,                  1 },
+   { PPC_FEATURE2_HAS_TAR,                   1 },
+   { PPC_FEATURE2_HAS_VEC_CRYPTO,            1 },
+   { PPC_FEATURE2_ARCH_3_00,                 1 },
+   { PPC_FEATURE2_HAS_IEEE128,               1 },
+   { PPC_FEATURE2_DARN,                      1 },
+   { PPC_FEATURE2_SCV,                       1 },
+   { PPC_FEATURE2_ARCH_3_1,                  1 },
+   { PPC_FEATURE2_MMA,                       1 },
+};
+
+#endif /* __CPU_FEATURES_H  */