ldconfig/x86: Store ISA level in cache and aux cache

Store ISA level in the portion of the unused upper 32 bits of the hwcaps
field in cache and the unused pad field in aux cache.  ISA level is stored
and checked only for shared objects in glibc-hwcaps subdirectories.  The
shared objects in the default directories aren't checked since there are
no fallbacks for these shared objects.

Tested on x86-64-v2, x86-64-v3 and x86-64-v4 machines with
--disable-hardcoded-path-in-tests and --enable-hardcoded-path-in-tests.

1 files changed, 34 insertions, 0 deletions

diff --git a/sysdeps/generic/elf-read-prop.h b/sysdeps/generic/elf-read-prop.h
new file mode 100644
index 0000000000..98c3d2acb5
--- /dev/null
+++ b/sysdeps/generic/elf-read-prop.h
@@ -0,0 +1,34 @@
+/* Support for GNU properties in ldconfig.  Generic version.
+   Copyright (C) 2021 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/>.  */
+
+#ifndef _ELF_READ_PROP_H
+#define _ELF_READ_PROP_H
+
+/* Called for each property in the NT_GNU_PROPERTY_TYPE_0 note of SEGMENT.
+   Return value:
+     false: Continue processing the properties.
+     true : Stop processing the properties.
+ */
+static inline bool __attribute__ ((always_inline))
+read_gnu_property (unsigned int *isal_level, uint32_t type, uint32_t
+		   datasz, void *data)
+{
+  return true;
+}
+
+#endif