This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
[PATCH 01/13] posix: Consolidate Linux pause syscall
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Fri, 12 May 2017 14:58:02 -0300
- Subject: [PATCH 01/13] posix: Consolidate Linux pause syscall
- Authentication-results: sourceware.org; auth=none
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.
---
ChangeLog | 10 ++++++++++
sysdeps/unix/sysv/linux/{generic => }/pause.c | 18 +++++++-----------
sysdeps/unix/sysv/linux/sparc/kernel-features.h | 6 ++++++
sysdeps/unix/sysv/linux/sparc/sparc64/pause.c | 9 ---------
sysdeps/unix/sysv/linux/syscalls.list | 1 -
5 files changed, 23 insertions(+), 21 deletions(-)
rename sysdeps/unix/sysv/linux/{generic => }/pause.c (75%)
delete mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/pause.c
diff --git a/sysdeps/unix/sysv/linux/generic/pause.c b/sysdeps/unix/sysv/linux/pause.c
similarity index 75%
rename from sysdeps/unix/sysv/linux/generic/pause.c
rename to sysdeps/unix/sysv/linux/pause.c
index a8b3e33..c6b252a 100644
--- a/sysdeps/unix/sysv/linux/generic/pause.c
+++ b/sysdeps/unix/sysv/linux/pause.c
@@ -1,6 +1,6 @@
-/* Copyright (C) 2011-2017 Free Software Foundation, Inc.
+/* Linux pause syscall implementation.
+ Copyright (C) 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
@@ -26,14 +26,10 @@
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;
+#ifdef __NR_pause
+ return SYSCALL_CANCEL (pause);
+#else
+ return SYSCALL_CANCEL (ppoll, 0, 0, 0, 0, 0);
+#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 72065a0..dd9108b 100644
--- a/sysdeps/unix/sysv/linux/sparc/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/sparc/kernel-features.h
@@ -32,6 +32,12 @@
# 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. */
+# ifdef __NR_pause
+# undef __NR_pause
+# endif
#endif
/* sparc only supports ipc syscall. */
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c b/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c
deleted file mode 100644
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 f4abf3e..eab30dd 100644
--- 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
--
2.7.4