s390x: Add glibc-hwcaps support

Subdirectories z13, z14, z15 can be selected, mostly based on the
level of support for vector instructions.

Co-Authored-By: Stefan Liebler <stli@linux.ibm.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/sysdeps/s390/s390-64/dl-hwcaps-subdirs.c b/sysdeps/s390/s390-64/dl-hwcaps-subdirs.c
new file mode 100644
index 0000000000..3673808a45
--- /dev/null
+++ b/sysdeps/s390/s390-64/dl-hwcaps-subdirs.c
@@ -0,0 +1,54 @@
+/* Architecture-specific glibc-hwcaps subdirectories.  s390x version.
+   Copyright (C) 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/>.  */
+
+#include <dl-hwcaps.h>
+#include <ldsodefs.h>
+
+const char _dl_hwcaps_subdirs[] = "z15:z14:z13";
+enum { subdirs_count = 3 }; /* Number of components in _dl_hwcaps_subdirs.  */
+
+uint32_t
+_dl_hwcaps_subdirs_active (void)
+{
+  int active = 0;
+
+  /* Test in reverse preference order.  */
+
+  /* z13.  */
+  if (!(GLRO (dl_hwcap) & HWCAP_S390_VX))
+    return _dl_hwcaps_subdirs_build_bitmask (subdirs_count, active);
+  ++active;
+
+  /* z14.  */
+  if (!((GLRO (dl_hwcap) & HWCAP_S390_VXD)
+        && (GLRO (dl_hwcap) & HWCAP_S390_VXE)
+        && (GLRO (dl_hwcap) & HWCAP_S390_GS)))
+    return _dl_hwcaps_subdirs_build_bitmask (subdirs_count, active);
+  ++active;
+
+  /* z15.
+     Note: We do not list HWCAP_S390_SORT and HWCAP_S390_DFLT here as,
+     according to the Principles of Operation, those may be replaced or removed
+     in future.  */
+  if (!((GLRO (dl_hwcap) & HWCAP_S390_VXRS_EXT2)
+        && (GLRO (dl_hwcap) & HWCAP_S390_VXRS_PDE)))
+    return _dl_hwcaps_subdirs_build_bitmask (subdirs_count, active);
+  ++active;
+
+  return _dl_hwcaps_subdirs_build_bitmask (subdirs_count, active);
+}