Add ifunc support for aarch64.

	* sysdeps/aarch64/dl-machine.h: Include cpu-features.c.
	(DL_PLATFORM_INIT): New define.
	(dl_platform_init): New function.
	* sysdeps/aarch64/ldsodefs.h: Include cpu-features.h.
	* sysdeps/unix/sysv/linux/aarch64/cpu-features.c: New file.
	* sysdeps/unix/sysv/linux/aarch64/cpu-features.h: Likewise.
	* sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c: Likewise.
	* sysdeps/unix/sysv/linux/aarch64/libc-start.c: Likewise.

7 files changed, 205 insertions, 0 deletions

diff --git a/sysdeps/aarch64/dl-machine.h b/sysdeps/aarch64/dl-machine.h
index 84b8aecfb8..15d79a6961 100644
--- a/sysdeps/aarch64/dl-machine.h
+++ b/sysdeps/aarch64/dl-machine.h
@@ -25,6 +25,7 @@
 #include <tls.h>
 #include <dl-tlsdesc.h>
 #include <dl-irel.h>
+#include <cpu-features.c>
 
 /* Return nonzero iff ELF header is compatible with the running host.  */
 static inline int __attribute__ ((unused))
@@ -225,6 +226,23 @@ _dl_start_user:								\n\
 #define ELF_MACHINE_NO_REL 1
 #define ELF_MACHINE_NO_RELA 0
 
+#define DL_PLATFORM_INIT dl_platform_init ()
+
+static inline void __attribute__ ((unused))
+dl_platform_init (void)
+{
+  if (GLRO(dl_platform) != NULL && *GLRO(dl_platform) == '\0')
+    /* Avoid an empty string which would disturb us.  */
+    GLRO(dl_platform) = NULL;
+
+#ifdef SHARED
+  /* init_cpu_features has been called early from __libc_start_main in
+     static executable.  */
+  init_cpu_features (&GLRO(dl_aarch64_cpu_features));
+#endif
+}
+
+
 static inline ElfW(Addr)
 elf_machine_fixup_plt (struct link_map *map, lookup_t t,
 		       const ElfW(Rela) *reloc,
diff --git a/sysdeps/aarch64/ldsodefs.h b/sysdeps/aarch64/ldsodefs.h
index f277074194..ba4ada3a04 100644
--- a/sysdeps/aarch64/ldsodefs.h
+++ b/sysdeps/aarch64/ldsodefs.h
@@ -20,6 +20,7 @@
 #define _AARCH64_LDSODEFS_H 1
 
 #include <elf.h>
+#include <cpu-features.h>
 
 struct La_aarch64_regs;
 struct La_aarch64_retval;
diff --git a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h
index 5975894521..cef3225af0 100644
--- a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h
+++ b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h
@@ -32,3 +32,4 @@
 #define HWCAP_ATOMICS		(1 << 8)
 #define HWCAP_FPHP		(1 << 9)
 #define HWCAP_ASIMDHP		(1 << 10)
+#define HWCAP_CPUID		(1 << 11)
diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
new file mode 100644
index 0000000000..702506249d
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
@@ -0,0 +1,35 @@
+/* Initialize CPU feature data.  AArch64 version.
+   This file is part of the GNU C Library.
+   Copyright (C) 2017 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <cpu-features.h>
+#include <sys/auxv.h>
+
+static inline void
+init_cpu_features (struct cpu_features *cpu_features)
+{
+  if (GLRO(dl_hwcap) & HWCAP_CPUID)
+    {
+      register uint64_t id = 0;
+      asm volatile ("mrs %0, midr_el1" : "=r"(id));
+      cpu_features->midr_el1 = id;
+    }
+  else
+    {
+      cpu_features->midr_el1 = 0;
+    }
+}
diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.h b/sysdeps/unix/sysv/linux/aarch64/cpu-features.h
new file mode 100644
index 0000000000..c92b650984
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.h
@@ -0,0 +1,49 @@
+/* Initialize CPU feature data.  AArch64 version.
+   This file is part of the GNU C Library.
+   Copyright (C) 2017 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
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _CPU_FEATURES_AARCH64_H
+#define _CPU_FEATURES_AARCH64_H
+
+#include <stdint.h>
+
+#define MIDR_PARTNUM_SHIFT	4
+#define MIDR_PARTNUM_MASK	(0xfff << MIDR_PARTNUM_SHIFT)
+#define MIDR_PARTNUM(midr)	\
+	(((midr) & MIDR_PARTNUM_MASK) >> MIDR_PARTNUM_SHIFT)
+#define MIDR_ARCHITECTURE_SHIFT	16
+#define MIDR_ARCHITECTURE_MASK	(0xf << MIDR_ARCHITECTURE_SHIFT)
+#define MIDR_ARCHITECTURE(midr)	\
+	(((midr) & MIDR_ARCHITECTURE_MASK) >> MIDR_ARCHITECTURE_SHIFT)
+#define MIDR_VARIANT_SHIFT	20
+#define MIDR_VARIANT_MASK	(0xf << MIDR_VARIANT_SHIFT)
+#define MIDR_VARIANT(midr)	\
+	(((midr) & MIDR_VARIANT_MASK) >> MIDR_VARIANT_SHIFT)
+#define MIDR_IMPLEMENTOR_SHIFT	24
+#define MIDR_IMPLEMENTOR_MASK	(0xff << MIDR_IMPLEMENTOR_SHIFT)
+#define MIDR_IMPLEMENTOR(midr)	\
+	(((midr) & MIDR_IMPLEMENTOR_MASK) >> MIDR_IMPLEMENTOR_SHIFT)
+
+#define IS_THUNDERX(midr) (MIDR_IMPLEMENTOR(midr) == 'C'	\
+			   && MIDR_PARTNUM(midr) == 0x0a1)
+
+struct cpu_features
+{
+  uint64_t midr_el1;
+};
+
+#endif /* _CPU_FEATURES_AARCH64_H  */
diff --git a/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c b/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c
new file mode 100644
index 0000000000..438046a562
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/dl-procinfo.c
@@ -0,0 +1,60 @@
+/* Data for AArch64 version of processor capability information.
+   Linux version.
+   Copyright (C) 2017 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
+   <http://www.gnu.org/licenses/>.  */
+
+/* If anything should be added here check whether the size of each string
+   is still ok with the given array size.
+
+   All the #ifdefs in the definitions are quite irritating but
+   necessary if we want to avoid duplicating the information.  There
+   are three different modes:
+
+   - PROCINFO_DECL is defined.  This means we are only interested in
+     declarations.
+
+   - PROCINFO_DECL is not defined:
+
+     + if SHARED is defined the file is included in an array
+       initializer.  The .element = { ... } syntax is needed.
+
+     + if SHARED is not defined a normal array initialization is
+       needed.
+  */
+
+#ifndef PROCINFO_CLASS
+# define PROCINFO_CLASS
+#endif
+
+#if !IS_IN (ldconfig)
+# if !defined PROCINFO_DECL && defined SHARED
+  ._dl_aarch64_cpu_features
+# else
+PROCINFO_CLASS struct cpu_features _dl_aarch64_cpu_features
+# endif
+# ifndef PROCINFO_DECL
+= { }
+# endif
+# if !defined SHARED || defined PROCINFO_DECL
+;
+# else
+,
+# endif
+#endif
+
+#undef PROCINFO_DECL
+#undef PROCINFO_CLASS
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc-start.c b/sysdeps/unix/sysv/linux/aarch64/libc-start.c
new file mode 100644
index 0000000000..a5babd49ea
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/libc-start.c
@@ -0,0 +1,41 @@
+/* Override csu/libc-start.c on AArch64.
+   Copyright (C) 2017 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
+   <http://www.gnu.org/licenses/>.  */
+
+#ifdef SHARED
+# include <csu/libc-start.c>
+# else
+/* The main work is done in the generic function.  */
+# define LIBC_START_DISABLE_INLINE
+# define LIBC_START_MAIN generic_start_main
+# include <csu/libc-start.c>
+# include <cpu-features.c>
+
+extern struct cpu_features _dl_aarch64_cpu_features;
+
+int
+__libc_start_main (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
+		   int argc, char **argv,
+		   __typeof (main) init,
+		   void (*fini) (void),
+		   void (*rtld_fini) (void), void *stack_end)
+{
+  init_cpu_features (&_dl_aarch64_cpu_features);
+  return generic_start_main (main, argc, argv, init, fini, rtld_fini,
+			     stack_end);
+}
+#endif