Refactor vDSO initialization code

Linux vDSO initialization code the internal function pointers require a
lot of duplicated boilerplate over different architectures.  This patch
aims to simplify not only the code but the required definition to enable
a vDSO symbol.

The changes are:

  1. Consolidate all init-first.c on only one implementation and enable
     the symbol based on HAVE_*_VSYSCALL existence.

  2. Set the HAVE_*_VSYSCALL to the architecture expected names string.

  3. Add a new internal implementation, get_vdso_mangle_symbol, which
     returns a mangled function pointer.

Currently the clock_gettime, clock_getres, gettimeofday, getcpu, and time
are handled in an arch-independent way, powerpc still uses some
arch-specific vDSO symbol handled in a specific init-first implementation.

Checked on aarch64-linux-gnu, arm-linux-gnueabihf, i386-linux-gnu,
mips64-linux-gnu, powerpc64le-linux-gnu, s390x-linux-gnu,
sparc64-linux-gnu, and x86_64-linux-gnu.

	* sysdeps/powerpc/powerpc32/backtrace.c (is_sigtramp_address,
	is_sigtramp_address_rt): Use HAVE_SIGTRAMP_{RT}32 instead of SHARED.
	* sysdeps/powerpc/powerpc64/backtrace.c (is_sigtramp_address):
	Likewise.
	* sysdeps/unix/sysv/linux/aarch64/init-first.c: Remove file.
	* sysdeps/unix/sysv/linux/aarch64/libc-vdso.h: Likewise.
	* sysdeps/unix/sysv/linux/arm/init-first.c: Likewise.
	* sysdeps/unix/sysv/linux/arm/libc-vdso.h: Likewise.
	* sysdeps/unix/sysv/linux/mips/init-first.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/libc-vdso.h: Likewise.
	* sysdeps/unix/sysv/linux/i386/init-first.c: Likewise.
	* sysdeps/unix/sysv/linux/riscv/init-first.c: Likewise.
	* sysdeps/unix/sysv/linux/riscv/libc-vdso.h: Likewise.
	* sysdeps/unix/sysv/linux/s390/init-first.c: Likewise.
	* sysdeps/unix/sysv/linux/s390/libc-vdso.h: Likewise.
	* sysdeps/unix/sysv/linux/sparc/init-first.c: Likewise.
	* sysdeps/unix/sysv/linux/sparc/libc-vdso.h: Likewise.
	* sysdeps/unix/sysv/linux/x86/libc-vdso.h: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/init-first.c: Likewise.
	* sysdeps/unix/sysv/linux/aarch64/sysdep.h
	(HAVE_CLOCK_GETRES_VSYSCALL, HAVE_CLOCK_GETTIME_VSYSCALL,
	HAVE_GETTIMEOFDAY_VSYSCALL): Define value based on kernel exported
	name.
	* sysdeps/unix/sysv/linux/arm/sysdep.h (HAVE_CLOCK_GETTIME_VSYSCALL,
	HAVE_GETTIMEOFDAY_VSYSCALL): Likewise.
	* sysdeps/unix/sysv/linux/i386/sysdep.h (HAVE_CLOCK_GETTIME_VSYSCALL,
	HAVE_GETTIMEOFDAY_VSYSCALL): Likewise.
	* sysdeps/unix/sysv/linux/mips/sysdep.h (HAVE_CLOCK_GETTIME_VSYSCALL,
	HAVE_GETTIMEOFDAY_VSYSCALL): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/sysdep.h
	(HAVE_CLOCK_GETRES_VSYSCALL, HAVE_CLOCK_GETTIME_VSYSCALL,
	HAVE_GETCPU_VSYSCALL, HAVE_TIME_VSYSCALL, HAVE_GET_TBFREQ,
	HAVE_SIGTRAMP_RT64, HAVE_SIGTRAMP_32, HAVE_SIGTRAMP_RT32i,
	HAVE_GETTIMEOFDAY_VSYSCALL): Likewise.
	* sysdeps/unix/sysv/linux/riscv/sysdep.h (HAVE_CLOCK_GETRES_VSYSCALL,
	HAVE_CLOCK_GETTIME_VSYSCALL, HAVE_GETTIMEOFDAY_VSYSCALL,
	HAVE_GETCPU_VSYSCALL): Likewise.
	* sysdeps/unix/sysv/linux/s390/sysdep.h (HAVE_CLOCK_GETRES_VSYSCALL,
	HAVE_CLOCK_GETTIME_VSYSCALL, HAVE_GETTIMEOFDAY_VSYSCALL,
	HAVE_GETCPU_VSYSCALL): Likewise.
	* sysdeps/unix/sysv/linux/sparc/sysdep.h (HAVE_CLOCK_GETTIME_VSYSCALL,
	HAVE_GETTIMEOFDAY_VSYSCALL): Likewise.
	* sysdeps/unix/sysv/linux/x86_64/sysdep.h
	(HAVE_CLOCK_GETTIME_VSYSCALL, HAVE_GETTIMEOFDAY_VSYSCALL,
	HAVE_GETCPU_VSYSCALL): Likewise.
	* sysdeps/unix/sysv/linux/dl-vdso.h (VDSO_NAME, VDSO_HASH): Define to
	invalid names if architecture does not define them.
	(get_vdso_mangle_symbol): New symbol.
	* sysdeps/unix/sysv/linux/init-first.c: New file.
	* sysdeps/unix/sysv/linux/libc-vdso.h: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/init-first.c (gettimeofday,
	clock_gettime, clock_getres, getcpu, time): Remove declaration.
	(__libc_vdso_platform_setup_arch): Likewise and use
	get_vdso_mangle_symbol to setup vDSO symbols.
	(sigtramp_rt64, sigtramp32, sigtramp_rt32, get_tbfreq): Add
	attribute_hidden.
	* sysdeps/unix/sysv/linux/powerpc/libc-vdso.h: Likewise.
	* sysdeps/unix/sysv/linux/sysdep-vdso.h (VDSO_SYMBOL): Remove
	definition.

1 files changed, 44 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/libc-vdso.h b/sysdeps/unix/sysv/linux/libc-vdso.h
new file mode 100644
index 0000000000..2e63aa1bba
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/libc-vdso.h
@@ -0,0 +1,44 @@
+/* Copyright (C) 2009-2019 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 _LIBC_VDSO_H
+#define _LIBC_VDSO_H
+
+#define VDSO_SYMBOL(__name) __vdso_##__name
+
+#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
+extern int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *)
+  attribute_hidden;
+#endif
+#ifdef HAVE_CLOCK_GETRES_VSYSCALL
+extern int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *)
+  attribute_hidden;
+#endif
+#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
+extern int (*VDSO_SYMBOL (gettimeofday)) (struct timeval *, void *)
+  attribute_hidden;
+#endif
+#ifdef HAVE_GETCPU_VSYSCALL
+extern long int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *, void *)
+  attribute_hidden;
+#endif
+#ifdef HAVE_TIME_VSYSCALL
+extern time_t (*VDSO_SYMBOL(time)) (time_t *) attribute_hidden;
+#endif
+
+#endif /* _LIBC_VDSO_H */