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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.
150 lines
5.5 KiB
C
150 lines
5.5 KiB
C
/* Set flags signalling availability of kernel features based on given
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kernel version number.
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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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/* This file must not contain any C code. At least it must be protected
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to allow using the file also in assembler files. */
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#ifndef __LINUX_KERNEL_VERSION
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/* We assume the worst; all kernels should be supported. */
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# define __LINUX_KERNEL_VERSION 0
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#endif
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/* We assume for __LINUX_KERNEL_VERSION the same encoding used in
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linux/version.h. I.e., the major, minor, and subminor all get a
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byte with the major number being in the highest byte. This means
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we can do numeric comparisons.
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In the following we will define certain symbols depending on
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whether the describes kernel feature is available in the kernel
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version given by __LINUX_KERNEL_VERSION. We are not always exactly
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recording the correct versions in which the features were
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introduced. If somebody cares these values can afterwards be
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corrected. */
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/* The sendfile syscall was introduced in 2.2.0. */
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#define __ASSUME_SENDFILE 1
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/* Some architectures use the socketcall multiplexer for some or all
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socket-related operations instead of separate syscalls.
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__ASSUME_SOCKETCALL is defined for such architectures. */
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/* The changed st_ino field appeared in 2.4.0-test6. However, SH is lame,
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and still does not have a 64-bit inode field. */
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#define __ASSUME_ST_INO_64_BIT 1
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/* The statfs64 syscalls are available in 2.5.74 (but not for alpha). */
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#define __ASSUME_STATFS64 1
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/* pselect/ppoll were introduced just after 2.6.16-rc1. On x86_64 and
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SH this appeared first in 2.6.19-rc1, on ia64 in 2.6.22-rc1. */
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#define __ASSUME_PSELECT 1
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/* The *at syscalls were introduced just after 2.6.16-rc1. On PPC
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they were introduced in 2.6.17-rc1, on SH in 2.6.19-rc1. */
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#define __ASSUME_ATFCTS 1
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/* Support for inter-process robust mutexes was added in 2.6.17 (but
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some architectures lack futex_atomic_cmpxchg_inatomic in some
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configurations). */
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#define __ASSUME_SET_ROBUST_LIST 1
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/* Support for private futexes was added in 2.6.22. */
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#define __ASSUME_PRIVATE_FUTEX 1
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/* Support for various CLOEXEC and NONBLOCK flags was added in
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2.6.23. */
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#define __ASSUME_O_CLOEXEC 1
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/* Support for various CLOEXEC and NONBLOCK flags was added in
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2.6.27. */
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#define __ASSUME_IN_NONBLOCK 1
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#define __ASSUME_PIPE2 1
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#define __ASSUME_DUP3 1
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/* Support for accept4 functionality was added in 2.6.28, but for some
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architectures using a separate syscall rather than socketcall that
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syscall was only added later, and some architectures first had
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socketcall support then a separate syscall. Define
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__ASSUME_ACCEPT4_SOCKETCALL if glibc uses socketcall on this
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architecture and accept4 is available through socketcall,
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__ASSUME_ACCEPT4_SYSCALL if it is available through a separate
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syscall, __ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL if it became
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available through a separate syscall at the same time as through
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socketcall, and __ASSUME_ACCEPT4 if the accept4 function is known
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to work. */
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#ifdef __ASSUME_SOCKETCALL
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# define __ASSUME_ACCEPT4_SOCKETCALL 1
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#endif
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#define __ASSUME_ACCEPT4_SYSCALL 1
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#define __ASSUME_ACCEPT4 1
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/* Support for the FUTEX_CLOCK_REALTIME flag was added in 2.6.29. */
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#define __ASSUME_FUTEX_CLOCK_REALTIME 1
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/* Support for preadv and pwritev was added in 2.6.30. */
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#define __ASSUME_PREADV 1
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#define __ASSUME_PWRITEV 1
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/* Support for FUTEX_*_REQUEUE_PI was added in 2.6.31 (but some
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architectures lack futex_atomic_cmpxchg_inatomic in some
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configurations). */
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#define __ASSUME_REQUEUE_PI 1
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/* Support for recvmmsg functionality was added in 2.6.33. The macros
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defined correspond to those for accept4. */
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#if __LINUX_KERNEL_VERSION >= 0x020621
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# ifdef __ASSUME_SOCKETCALL
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# define __ASSUME_RECVMMSG_SOCKETCALL 1
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# endif
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# define __ASSUME_RECVMMSG_SYSCALL 1
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# define __ASSUME_RECVMMSG 1
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#endif
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/* Support for /proc/self/task/$tid/comm and /proc/$pid/task/$tid/comm was
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added in 2.6.33. */
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#if __LINUX_KERNEL_VERSION >= 0x020621
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# define __ASSUME_PROC_PID_TASK_COMM 1
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#endif
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/* statfs fills in f_flags since 2.6.36. */
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#if __LINUX_KERNEL_VERSION >= 0x020624
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# define __ASSUME_STATFS_F_FLAGS 1
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#endif
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/* prlimit64 is available in 2.6.36. */
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#if __LINUX_KERNEL_VERSION >= 0x020624
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# define __ASSUME_PRLIMIT64 1
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#endif
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/* Support for sendmmsg functionality was added in 3.0. The macros
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defined correspond to those for accept4 and recvmmsg. */
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#if __LINUX_KERNEL_VERSION >= 0x030000
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# ifdef __ASSUME_SOCKETCALL
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# define __ASSUME_SENDMMSG_SOCKETCALL 1
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# endif
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# define __ASSUME_SENDMMSG_SYSCALL 1
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# define __ASSUME_SENDMMSG 1
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#endif
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/* On most architectures, most socket syscalls are supported for all
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supported kernel versions, but on some socketcall architectures
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separate syscalls were only added later. */
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#define __ASSUME_SENDMSG_SYSCALL 1
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#define __ASSUME_RECVMSG_SYSCALL 1
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