posix: Consolidate Linux pause syscall

This patch consolidates the pause Linux implementation on
sysdeps/unix/sysv/linux/pause.c.  If defined the pause syscall
(__NR_pause) will be used, other ppoll with 0 arguments will be
used instead.

It has the small advantage of generic pause implementation with
uses rt_sigprocmask plus rt_sigsuspend because it requires only
one syscall and the pause is done atomically regarding signal
handling (for instance, pause may not be interrupted if the
signal arrives between the rt_sigprocmask and rt_sigsuspend
syscall).

Checked on i686-linux-gnu, x86_64-linux-gnu, x86_64-linux-gnux32,
arch64-linux-gnu, arm-linux-gnueabihf, powerpc64le-linux-gnu,
sparc64-linux-gnu, and sparcv9-linux-gnu.

	* sysdeps/unix/sysv/linux/generic/pause.c: Remove file.
	* sysdeps/unix/sysv/linux/sparc/sparc64/pause.c: Likewise.
	* sysdeps/unix/sysv/linux/sparc/kernel-features.h [__arch64__]
	(__NR_pause): Undefine.
	* sysdeps/unix/sysv/linux/pause.c: New file.
	* sysdeps/unix/sysv/linux/syscalls.list: Remove pause from
	auto-generation list.

diff --git a/ChangeLog b/ChangeLog
index 5ebd3a04abce97649186230333765d38121baef8..135b5a5e87e3a91f0df73ad1e1d9e5e758d968ad 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2017-05-18  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
+
+       * sysdeps/unix/sysv/linux/generic/pause.c: Remove file.
+       * sysdeps/unix/sysv/linux/sparc/sparc64/pause.c: Likewise.
+       * sysdeps/unix/sysv/linux/sparc/kernel-features.h [__arch64__]
+       (__NR_pause): Undefine.
+       * sysdeps/unix/sysv/linux/pause.c: New file.
+       * sysdeps/unix/sysv/linux/syscalls.list: Remove pause from
+       auto-generation list.
+       * sysdeps/unix/sysv/linux/sparc/sparc64/Makefile (CFLAGS-pause.c):
+       Remove rule.
+       * posix/Makefile (CFLAGS-pause.c): Remove redundant rule.
+
 2017-05-18  H.J. Lu  <hongjiu.lu@intel.com>
 
        * sysdeps/x86_64/multiarch/memcmp.S (__GI_memcmp): Correct

diff --git a/posix/Makefile b/posix/Makefile
index 0025d8af53b0ccfdbe97c825ab60cbf5264e4314..a78ca3dd717f57b5c448a102840c09d35f20c5c0 100644 (file)
--- a/posix/Makefile
+++ b/posix/Makefile
@@ -221,7 +221,6 @@ CFLAGS-spawnp.c = -fexceptions
 CFLAGS-spawnp.os = -fomit-frame-pointer
 CFLAGS-spawni.c = -fexceptions
 CFLAGS-spawni.os = -fomit-frame-pointer
-CFLAGS-pause.c = -fexceptions
 CFLAGS-glob.c = $(uses-callbacks) -fexceptions
 CFLAGS-glob64.c = $(uses-callbacks) -fexceptions
 CFLAGS-getconf.c = -DGETCONF_DIR='"$(libexecdir)/getconf"'

diff --git a/sysdeps/unix/sysv/linux/generic/pause.c b/sysdeps/unix/sysv/linux/generic/pause.c
deleted file mode 100644 (file)
index a8b3e33..0000000
--- a/sysdeps/unix/sysv/linux/generic/pause.c
+++ /dev/null
@@ -1,39 +0,0 @@
-/* Copyright (C) 2011-2017 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
-
-   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 <signal.h>
-#include <unistd.h>
-#include <sysdep-cancel.h>
-
-/* Suspend the process until a signal arrives.
-   This always returns -1 and sets errno to EINTR.  */
-
-int
-__libc_pause (void)
-{
-  sigset_t set;
-
-  int rc =
-    SYSCALL_CANCEL (rt_sigprocmask, SIG_BLOCK, NULL, &set, _NSIG / 8);
-  if (rc == 0)
-    rc = SYSCALL_CANCEL (rt_sigsuspend, &set, _NSIG / 8);
-
-  return rc;
-}
-
-weak_alias (__libc_pause, pause)

diff --git a/sysdeps/unix/sysv/linux/pause.c b/sysdeps/unix/sysv/linux/pause.c
new file mode 100644 (file)
index 0000000..4ccce9e
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/pause.c
@@ -0,0 +1,35 @@
+/* Linux pause syscall implementation.
+   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/>.  */
+
+#include <signal.h>
+#include <unistd.h>
+#include <sysdep-cancel.h>
+
+/* Suspend the process until a signal arrives.
+   This always returns -1 and sets errno to EINTR.  */
+
+int
+__libc_pause (void)
+{
+#ifdef __NR_pause
+  return SYSCALL_CANCEL (pause);
+#else
+  return SYSCALL_CANCEL (ppoll, NULL, 0, NULL, NULL);
+#endif
+}
+weak_alias (__libc_pause, pause)

diff --git a/sysdeps/unix/sysv/linux/sparc/kernel-features.h b/sysdeps/unix/sysv/linux/sparc/kernel-features.h
index 72065a0248afa317c798e4d9545e98f4d4e28fa2..3fafab359ca6757351228c7d9c421489ad256cf6 100644 (file)
--- a/sysdeps/unix/sysv/linux/sparc/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/sparc/kernel-features.h
@@ -32,6 +32,10 @@
 # undef __ASSUME_ACCEPT_SYSCALL
 # undef __ASSUME_CONNECT_SYSCALL
 # undef __ASSUME_RECVFROM_SYSCALL
+#else
+/* sparc64 defines __NR_pause,  however it is not supported (ENOSYS).
+   Undefine so pause.c can use a correct alternative.  */
+# undef __NR_pause
 #endif
 
 /* sparc only supports ipc syscall.  */

diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/Makefile b/sysdeps/unix/sysv/linux/sparc/sparc64/Makefile
index 7ea433f21fbccbd8ec38a78abebcdd910230ef7a..3a7f4aa84a88858129c1e9e9574b1ff46430072e 100644 (file)
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/Makefile
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/Makefile
@@ -9,6 +9,5 @@ sysdep_routines += __start_context
 endif
 
 ifeq ($(subdir),nptl)
-CFLAGS-pause.c += -fexceptions
 CFLAGS-sigsuspend.c += -fexceptions
 endif

diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c b/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c
deleted file mode 100644 (file)
index e399e7c..0000000
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c
+++ /dev/null
@@ -1,9 +0,0 @@
-#include <errno.h>
-#include <signal.h>
-#include <unistd.h>
-#include <sysdep-cancel.h>
-
-#define __sigprocmask(how, set, oset) \
-  INLINE_SYSCALL (rt_sigprocmask, 4, how, set, oset, _NSIG / 8)
-
-#include <sysdeps/posix/pause.c>

diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
index f4abf3e6c85fccbe98387a2b7a618412451a7ad9..eab30dda06773b5246b314fa191ca13be3fc012e 100644 (file)
--- a/sysdeps/unix/sysv/linux/syscalls.list
+++ b/sysdeps/unix/sysv/linux/syscalls.list
@@ -44,7 +44,6 @@ munlock               -       munlock         i:ai    munlock
 munlockall     -       munlockall      i:      munlockall
 nanosleep      -       nanosleep       Ci:pp   __nanosleep     nanosleep
 nfsservctl     EXTRA   nfsservctl      i:ipp   nfsservctl
-pause          -       pause           Ci:     __libc_pause    pause
 pipe           -       pipe            i:f     __pipe          pipe
 pipe2          -       pipe2           i:fi    __pipe2         pipe2
 pivot_root     EXTRA   pivot_root      i:ss    pivot_root