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.

3 files changed, 4 insertions, 95 deletions

diff --git a/sysdeps/unix/sysv/linux/s390/init-first.c b/sysdeps/unix/sysv/linux/s390/init-first.c
deleted file mode 100644
index ac4c536114..0000000000
--- a/sysdeps/unix/sysv/linux/s390/init-first.c
+++ /dev/null
@@ -1,56 +0,0 @@
-/* Initialization code run first thing by the ELF startup code.  Linux/s390.
-   Copyright (C) 2008-2019 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/>.  */
-
-#include <dl-vdso.h>
-#include <libc-vdso.h>
-
-long int (*VDSO_SYMBOL(gettimeofday)) (struct timeval *, void *)
-   attribute_hidden;
-
-long int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *)
-  __attribute__ ((nocommon));
-
-long int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *)
-  __attribute__ ((nocommon));
-
-long int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *, void *)
-   attribute_hidden;
-
-static inline void
-_libc_vdso_platform_setup (void)
-{
-  void *p = get_vdso_symbol ("__kernel_gettimeofday");
-  PTR_MANGLE (p);
-  VDSO_SYMBOL (gettimeofday) = p;
-
-  p = get_vdso_symbol ("__kernel_clock_gettime");
-  PTR_MANGLE (p);
-  VDSO_SYMBOL (clock_gettime) = p;
-
-  p = get_vdso_symbol ("__kernel_clock_getres");
-  PTR_MANGLE (p);
-  VDSO_SYMBOL (clock_getres) = p;
-
-  p = get_vdso_symbol ("__kernel_getcpu");
-  PTR_MANGLE (p);
-  VDSO_SYMBOL (getcpu) = p;
-}
-
-#define VDSO_SETUP _libc_vdso_platform_setup
-
-#include <csu/init-first.c>
diff --git a/sysdeps/unix/sysv/linux/s390/libc-vdso.h b/sysdeps/unix/sysv/linux/s390/libc-vdso.h
deleted file mode 100644
index a162ad8244..0000000000
--- a/sysdeps/unix/sysv/linux/s390/libc-vdso.h
+++ /dev/null
@@ -1,35 +0,0 @@
-/* Resolve function pointers to VDSO functions.
-   Copyright (C) 2008-2019 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
-
-#include <sysdep-vdso.h>
-
-extern long int (*VDSO_SYMBOL(gettimeofday)) (struct timeval *, void *)
-   attribute_hidden;
-
-extern long int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *);
-
-extern long int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *);
-
-extern long int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *, void *)
-   attribute_hidden;
-
-#endif /* _LIBC_VDSO_H */
diff --git a/sysdeps/unix/sysv/linux/s390/sysdep.h b/sysdeps/unix/sysv/linux/s390/sysdep.h
index 3dfb359e9d..97d78e246c 100644
--- a/sysdeps/unix/sysv/linux/s390/sysdep.h
+++ b/sysdeps/unix/sysv/linux/s390/sysdep.h
@@ -20,7 +20,7 @@
 #define VDSO_HASH  123718585
 
 /* List of system calls which are supported as vsyscalls.  */
-#define HAVE_CLOCK_GETRES_VSYSCALL	1
-#define HAVE_CLOCK_GETTIME_VSYSCALL	1
-#define HAVE_GETTIMEOFDAY_VSYSCALL	1
-#define HAVE_GETCPU_VSYSCALL		1
+#define HAVE_CLOCK_GETRES_VSYSCALL	"__kernel_clock_getres"
+#define HAVE_CLOCK_GETTIME_VSYSCALL	"__kernel_clock_gettime"
+#define HAVE_GETTIMEOFDAY_VSYSCALL	"__kernel_gettimeofday"
+#define HAVE_GETCPU_VSYSCALL		"__kernel_getcpu"