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>

3 files changed, 175 insertions, 0 deletions

diff --git a/sysdeps/s390/s390-64/Makefile b/sysdeps/s390/s390-64/Makefile
index b4d793b..e5da268 100644
--- a/sysdeps/s390/s390-64/Makefile
+++ b/sysdeps/s390/s390-64/Makefile
@@ -6,4 +6,43 @@ ifeq ($(subdir),elf)
 CFLAGS-rtld.c += -Wno-uninitialized -Wno-unused
 CFLAGS-dl-load.c += -Wno-unused
 CFLAGS-dl-reloc.c += -Wno-unused
+
+$(objpfx)tst-glibc-hwcaps: $(objpfx)libmarkermod2-1.so \
+  $(objpfx)libmarkermod3-1.so $(objpfx)libmarkermod4-1.so
+$(objpfx)tst-glibc-hwcaps.out: \
+  $(objpfx)libmarkermod2.so \
+    $(objpfx)glibc-hwcaps/z13/libmarkermod2.so \
+  $(objpfx)libmarkermod3.so \
+    $(objpfx)glibc-hwcaps/z13/libmarkermod3.so \
+    $(objpfx)glibc-hwcaps/z14/libmarkermod3.so \
+  $(objpfx)libmarkermod4.so \
+    $(objpfx)glibc-hwcaps/z13/libmarkermod4.so \
+    $(objpfx)glibc-hwcaps/z14/libmarkermod4.so \
+    $(objpfx)glibc-hwcaps/z15/libmarkermod4.so \
+
+$(objpfx)glibc-hwcaps/z13/libmarkermod2.so: $(objpfx)libmarkermod2-2.so
+	$(make-target-directory)
+	cp $< $@
+$(objpfx)glibc-hwcaps/z13/libmarkermod3.so: $(objpfx)libmarkermod3-2.so
+	$(make-target-directory)
+	cp $< $@
+$(objpfx)glibc-hwcaps/z14/libmarkermod3.so: $(objpfx)libmarkermod3-3.so
+	$(make-target-directory)
+	cp $< $@
+$(objpfx)glibc-hwcaps/z13/libmarkermod4.so: $(objpfx)libmarkermod4-2.so
+	$(make-target-directory)
+	cp $< $@
+$(objpfx)glibc-hwcaps/z14/libmarkermod4.so: $(objpfx)libmarkermod4-3.so
+	$(make-target-directory)
+	cp $< $@
+$(objpfx)glibc-hwcaps/z15/libmarkermod4.so: $(objpfx)libmarkermod4-4.so
+	$(make-target-directory)
+	cp $< $@
+
+ifeq (no,$(build-hardcoded-path-in-tests))
+# This is an ld.so.cache test, and RPATH/RUNPATH in the executable
+# interferes with its test objectives.
+tests-container += tst-glibc-hwcaps-cache
 endif
+
+endif # $(subdir) == elf
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 0000000..3673808
--- /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);
+}
diff --git a/sysdeps/s390/s390-64/tst-glibc-hwcaps.c b/sysdeps/s390/s390-64/tst-glibc-hwcaps.c
new file mode 100644
index 0000000..690f0d5
--- /dev/null
+++ b/sysdeps/s390/s390-64/tst-glibc-hwcaps.c
@@ -0,0 +1,82 @@
+/* glibc-hwcaps subdirectory test.  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 <stdio.h>
+#include <string.h>
+#include <support/check.h>
+#include <sys/auxv.h>
+#include <sys/param.h>
+
+extern int marker2 (void);
+extern int marker3 (void);
+extern int marker4 (void);
+
+/* Return the arch level, 10 for the baseline libmarkermod*.so's.  */
+static int
+compute_level (void)
+{
+  const char *platform = (const char *) getauxval (AT_PLATFORM);
+
+  /* The arch* versions refer to the edition of the Principles of
+     Operation, and they are off by two when compared with the recent
+     product names.  (The code below should not be considered an
+     accurate mapping to Principles of Operation editions for earlier
+     AT_PLATFORM strings).  */
+  if (strcmp (platform, "z900") == 0)
+    return 10;
+  if (strcmp (platform, "z990") == 0)
+    return 10;
+  if (strcmp (platform, "z9-109") == 0)
+    return 10;
+  if (strcmp (platform, "z10") == 0)
+    return 10;
+  if (strcmp (platform, "z196") == 0)
+    return 10;
+  if (strcmp (platform, "zEC12") == 0)
+    return 10;
+
+  /* If we are running on z13 or newer and the kernel was booted with novx,
+     then AT_PLATFORM is z13 or newer, but _dl_hwcaps_subdirs_active will
+     return zero and the _dl_hwcaps_subdirs are not searched.  */
+  const unsigned long int hwcap = getauxval (AT_HWCAP);
+  if ((hwcap & HWCAP_S390_VX) == 0)
+    return 10;
+
+  if (strcmp (platform, "z13") == 0)
+    return 11;
+  if (strcmp (platform, "z14") == 0)
+    return 12;
+  if (strcmp (platform, "z15") == 0)
+    return 13;
+  printf ("warning: unrecognized AT_PLATFORM value: %s\n", platform);
+  /* Assume that the new platform supports z15.  */
+  return 13;
+}
+
+static int
+do_test (void)
+{
+  int level = compute_level ();
+  printf ("info: detected architecture level: arch%d\n", level);
+  TEST_COMPARE (marker2 (), MIN (level - 9, 2));
+  TEST_COMPARE (marker3 (), MIN (level - 9, 3));
+  TEST_COMPARE (marker4 (), MIN (level - 9, 4));
+  return 0;
+}
+
+#include <support/test-driver.c>