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f5c77f78ec
This patch removes __ASSUME_FUTEX_LOCK_PI usage and assumes that
kernel will correctly return if it supports or not
futex_atomic_cmpxchg_inatomic.
Current PI mutex code already has runtime support by calling
prio_inherit_missing and returns ENOTSUP if the futex operation fails
at initialization (it issues a FUTEX_UNLOCK_PI futex operation).
Also, current minimum supported kernel (v3.2) will return ENOSYS if
futex_atomic_cmpxchg_inatomic is not supported in the system:
kernel/futex.c:
2628 long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
2629 u32 __user *uaddr2, u32 val2, u32 val3)
2630 {
2631 int ret = -ENOSYS, cmd = op & FUTEX_CMD_MASK;
[...]
2667 case FUTEX_UNLOCK_PI:
2668 if (futex_cmpxchg_enabled)
2669 ret = futex_unlock_pi(uaddr, flags);
[...]
2686 return ret;
2687 }
The futex_cmpxchg_enabled is initialized by calling cmpxchg_futex_value_locked,
which calls futex_atomic_cmpxchg_inatomic.
For ARM futex_atomic_cmpxchg_inatomic will be either defined (if both
CONFIG_CPU_USE_DOMAINS and CONFIG_SMP are not defined) or use the
default generic implementation that returns ENOSYS.
For m68k is uses the default generic implementation.
For mips futex_atomic_cmpxchg_inatomic will return ENOSYS if cpu has no
'cpu_has_llsc' support (defined by each chip supporte inside kernel).
For sparc, 32-bit kernel will just use default generic implementation,
while 64-bit kernel has support.
Tested on ARM (v3.8 kernel) and x86_64.
* nptl/pthread_mutex_init.c [__ASSUME_FUTEX_LOCK_PI]
(prio_inherit_missing): Remove define.
* sysdeps/unix/sysv/linux/arm/kernel-features.h
(__ASSUME_FUTEX_LOCK_PI): Likewise.
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_FUTEX_LOCK_PI):
Likewise.
* sysdeps/unix/sysv/linux/m68k/kernel-features.h
(__ASSUME_FUTEX_LOCK_PI): Likewise.
* sysdeps/unix/sysv/linux/mips/kernel-features.h
(__ASSUME_FUTEX_LOCK_PI): Likewise.
* sysdeps/unix/sysv/linux/sparc/kernel-features.h
(__ASSUME_FUTEX_LOCK_PI): Likewise.
40 lines
1.5 KiB
C
40 lines
1.5 KiB
C
/* Set flags signalling availability of kernel features based on given
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kernel version number. SPARC version.
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Copyright (C) 1999-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/* SPARC uses socketcall. */
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#define __ASSUME_SOCKETCALL 1
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/* The accept4 syscall was added for SPARC in 2.6.28. */
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#define __ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL 1
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/* The recvmmsg syscall was added for SPARC in 2.6.33. */
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#define __ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL 1
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/* The sendmmsg syscall was added for SPARC in 3.0. */
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#define __ASSUME_SENDMMSG_SYSCALL_WITH_SOCKETCALL 1
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#include_next <kernel-features.h>
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/* 32-bit SPARC kernels do not support
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futex_atomic_cmpxchg_inatomic. */
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#if !defined __arch64__ && !defined __sparc_v9__
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# undef __ASSUME_REQUEUE_PI
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# undef __ASSUME_SET_ROBUST_LIST
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#endif
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