Linux: Consolidate {RTLD_}SINGLE_THREAD_P definition

Current GLIBC has two ways to implement the single thread optimization
on syscalls to avoid calling the cancellation path: either by using
global variables (__{libc,pthread}_multiple_thread) or by accessing
the TCB field (defined by TLS_MULTIPLE_THREADS_IN_TCB).  Both the
variables and the macros to acces its value are defined in the
architecture sysdep-cancel.h header.

This patch consolidates its definition on only one header,
sysdeps/unix/sysv/linux/sysdep-cancel.h, and adds a new define
(SINGLE_THREAD_BY_GLOBAL) which the architecture defines if it prefer
to use the global variables instead of the TCB field.  This is an
optimization, so if the architecture does not define it, the TCB
method will be used as default.

Checked on x86_64-linux-gnu and on a build with major touched
ABIs (aarch64-linux-gnu, alpha-linux-gnu, arm-linux-gnueabihf,
hppa-linux-gnu, i686-linux-gnu, m68k-linux-gnu, microblaze-linux-gnu,
mips-linux-gnu, mips64-linux-gnu, powerpc-linux-gnu,
powerpc64le-linux-gnu, s390-linux-gnu, s390x-linux-gnu, sh4-linux-gnu,
sparcv9-linux-gnu, sparc64-linux-gnu, tilegx-linux-gnu).

	* sysdeps/unix/sysv/linux/aarch64/sysdep-cancel.h: Remove file.
	* sysdeps/unix/sysv/linux/alpha/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/arm/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/hppa/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/mips/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/nios2/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/sh/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/tile/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/sysdep-cancel.h: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h
	(SINGLE_THREAD_BY_GLOBAL): Define.
	* sysdeps/unix/sysv/linux/aarch64/sysdep.h (SINGLE_THREAD_BY_GLOBAL):
	Likewise.
	* sysdeps/unix/sysv/linux/alpha/sysdep.h (SINGLE_THREAD_BY_GLOBAL):
	Likewise.
	* sysdeps/unix/sysv/linux/arm/sysdep.h (SINGLE_THREAD_BY_GLOBAL):
	Likewise.
	* sysdeps/unix/sysv/linux/hppa/sysdep.h (SINGLE_THREAD_BY_GLOBAL):
	Likewise.
	* sysdeps/unix/sysv/linux/microblaze/sysdep.h
	(SINGLE_THREAD_BY_GLOBAL): Likewise.
	* sysdeps/unix/sysv/linux/x86_64/sysdep.h (SINGLE_THREAD_BY_GLOBAL):
	Likewise.

2 files changed, 2 insertions, 47 deletions

diff --git a/sysdeps/unix/sysv/linux/arm/sysdep-cancel.h b/sysdeps/unix/sysv/linux/arm/sysdep-cancel.h
deleted file mode 100644
index b227187ab9..0000000000
--- a/sysdeps/unix/sysv/linux/arm/sysdep-cancel.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/* Copyright (C) 2003-2017 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/>.  */
-
-#include <sysdep.h>
-#include <tls.h>
-#include <nptl/pthreadP.h>
-
-#if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt)
-
-# if IS_IN (libpthread)
-#  define __local_multiple_threads __pthread_multiple_threads
-# elif IS_IN (libc)
-#  define __local_multiple_threads __libc_multiple_threads
-# endif
-
-# if IS_IN (libpthread) || IS_IN (libc)
-extern int __local_multiple_threads attribute_hidden;
-#  define SINGLE_THREAD_P __glibc_likely (__local_multiple_threads == 0)
-# else
-/*  There is no __local_multiple_threads for librt, so use the TCB.  */
-#  define SINGLE_THREAD_P						\
-  __glibc_likely (THREAD_GETMEM (THREAD_SELF, header.multiple_threads) == 0)
-# endif
-
-#else
-
-/* For rtld, et cetera.  */
-# define SINGLE_THREAD_P 1
-
-#endif
-
-#define RTLD_SINGLE_THREAD_P \
-  __glibc_likely (THREAD_GETMEM (THREAD_SELF, header.multiple_threads) == 0)
diff --git a/sysdeps/unix/sysv/linux/arm/sysdep.h b/sysdeps/unix/sysv/linux/arm/sysdep.h
index 3ca2198596..6a64351cdd 100644
--- a/sysdeps/unix/sysv/linux/arm/sysdep.h
+++ b/sysdeps/unix/sysv/linux/arm/sysdep.h
@@ -437,6 +437,8 @@ __local_syscall_error:						\
 #define INTERNAL_SYSCALL_NCS(number, err, nr, args...)          \
   INTERNAL_SYSCALL_RAW (number, err, nr, args)
 
+#define SINGLE_THREAD_BY_GLOBAL	1
+
 #endif	/* __ASSEMBLER__ */
 
 #endif /* linux/arm/sysdep.h */