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glibc/sysdeps/unix/sysv/linux/kernel-features.h
Adhemerval Zanella f5c77f78ec Remove __ASSUME_FUTEX_LOCK_PI 
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.
2016-06-13 08:36:34 -03:00

150 lines
5.5 KiB
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/* Set flags signalling availability of kernel features based on given
kernel version number.
Copyright (C) 1999-2016 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/>. */
/* This file must not contain any C code. At least it must be protected
to allow using the file also in assembler files. */
#ifndef __LINUX_KERNEL_VERSION
/* We assume the worst; all kernels should be supported. */
# define __LINUX_KERNEL_VERSION 0
#endif
/* We assume for __LINUX_KERNEL_VERSION the same encoding used in
linux/version.h. I.e., the major, minor, and subminor all get a
byte with the major number being in the highest byte. This means
we can do numeric comparisons.
In the following we will define certain symbols depending on
whether the describes kernel feature is available in the kernel
version given by __LINUX_KERNEL_VERSION. We are not always exactly
recording the correct versions in which the features were
introduced. If somebody cares these values can afterwards be
corrected. */
/* The sendfile syscall was introduced in 2.2.0. */
#define __ASSUME_SENDFILE 1
/* Some architectures use the socketcall multiplexer for some or all
socket-related operations instead of separate syscalls.
__ASSUME_SOCKETCALL is defined for such architectures. */
/* The changed st_ino field appeared in 2.4.0-test6. However, SH is lame,
and still does not have a 64-bit inode field. */
#define __ASSUME_ST_INO_64_BIT 1
/* The statfs64 syscalls are available in 2.5.74 (but not for alpha). */
#define __ASSUME_STATFS64 1
/* pselect/ppoll were introduced just after 2.6.16-rc1. On x86_64 and
SH this appeared first in 2.6.19-rc1, on ia64 in 2.6.22-rc1. */
#define __ASSUME_PSELECT 1
/* The *at syscalls were introduced just after 2.6.16-rc1. On PPC
they were introduced in 2.6.17-rc1, on SH in 2.6.19-rc1. */
#define __ASSUME_ATFCTS 1
/* Support for inter-process robust mutexes was added in 2.6.17 (but
some architectures lack futex_atomic_cmpxchg_inatomic in some
configurations). */
#define __ASSUME_SET_ROBUST_LIST 1
/* Support for private futexes was added in 2.6.22. */
#define __ASSUME_PRIVATE_FUTEX 1
/* Support for various CLOEXEC and NONBLOCK flags was added in
2.6.23. */
#define __ASSUME_O_CLOEXEC 1
/* Support for various CLOEXEC and NONBLOCK flags was added in
2.6.27. */
#define __ASSUME_IN_NONBLOCK 1
#define __ASSUME_PIPE2 1
#define __ASSUME_DUP3 1
/* Support for accept4 functionality was added in 2.6.28, but for some
architectures using a separate syscall rather than socketcall that
syscall was only added later, and some architectures first had
socketcall support then a separate syscall. Define
__ASSUME_ACCEPT4_SOCKETCALL if glibc uses socketcall on this
architecture and accept4 is available through socketcall,
__ASSUME_ACCEPT4_SYSCALL if it is available through a separate
syscall, __ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL if it became
available through a separate syscall at the same time as through
socketcall, and __ASSUME_ACCEPT4 if the accept4 function is known
to work. */
#ifdef __ASSUME_SOCKETCALL
# define __ASSUME_ACCEPT4_SOCKETCALL 1
#endif
#define __ASSUME_ACCEPT4_SYSCALL 1
#define __ASSUME_ACCEPT4 1
/* Support for the FUTEX_CLOCK_REALTIME flag was added in 2.6.29. */
#define __ASSUME_FUTEX_CLOCK_REALTIME 1
/* Support for preadv and pwritev was added in 2.6.30. */
#define __ASSUME_PREADV 1
#define __ASSUME_PWRITEV 1
/* Support for FUTEX_*_REQUEUE_PI was added in 2.6.31 (but some
architectures lack futex_atomic_cmpxchg_inatomic in some
configurations). */
#define __ASSUME_REQUEUE_PI 1
/* Support for recvmmsg functionality was added in 2.6.33. The macros
defined correspond to those for accept4. */
#if __LINUX_KERNEL_VERSION >= 0x020621
# ifdef __ASSUME_SOCKETCALL
# define __ASSUME_RECVMMSG_SOCKETCALL 1
# endif
# define __ASSUME_RECVMMSG_SYSCALL 1
# define __ASSUME_RECVMMSG 1
#endif
/* Support for /proc/self/task/$tid/comm and /proc/$pid/task/$tid/comm was
added in 2.6.33. */
#if __LINUX_KERNEL_VERSION >= 0x020621
# define __ASSUME_PROC_PID_TASK_COMM 1
#endif
/* statfs fills in f_flags since 2.6.36. */
#if __LINUX_KERNEL_VERSION >= 0x020624
# define __ASSUME_STATFS_F_FLAGS 1
#endif
/* prlimit64 is available in 2.6.36. */
#if __LINUX_KERNEL_VERSION >= 0x020624
# define __ASSUME_PRLIMIT64 1
#endif
/* Support for sendmmsg functionality was added in 3.0. The macros
defined correspond to those for accept4 and recvmmsg. */
#if __LINUX_KERNEL_VERSION >= 0x030000
# ifdef __ASSUME_SOCKETCALL
# define __ASSUME_SENDMMSG_SOCKETCALL 1
# endif
# define __ASSUME_SENDMMSG_SYSCALL 1
# define __ASSUME_SENDMMSG 1
#endif
/* On most architectures, most socket syscalls are supported for all
supported kernel versions, but on some socketcall architectures
separate syscalls were only added later. */
#define __ASSUME_SENDMSG_SYSCALL 1
#define __ASSUME_RECVMSG_SYSCALL 1
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