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Consolidate futex-internal.h

Browse Source 
NPTL is already Linux specific, there is no need to parametrize futex
operations and add a sysdep Linux specific implementation.  This patch
moves the relevant Linux code to nptl one.

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This commit is contained in:
Adhemerval Zanella
2019-10-29 18:52:19 -03:00
parent ff12e0fb91
commit b865eed0ac
2 changed files with 196 additions and 270 deletions
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211
sysdeps/nptl/futex-internal.h
View File

@ -74,11 +74,35 @@
# error FUTEX_PRIVATE must be equal to 0 # error FUTEX_PRIVATE must be equal to 0
#endif #endif
/* Calls __libc_fatal with an error message. Convenience function for
concrete implementations of the futex interface. */
static __always_inline __attribute__ ((__noreturn__)) void
futex_fatal_error (void)
{
__libc_fatal ("The futex facility returned an unexpected error code.\n");
}
/* The Linux kernel treats provides absolute timeouts based on the
CLOCK_REALTIME clock and relative timeouts measured against the
CLOCK_MONOTONIC clock.
We expect a Linux kernel version of 2.6.22 or more recent (since this
version, EINTR is not returned on spurious wake-ups anymore). */
/* Returns EINVAL if PSHARED is neither PTHREAD_PROCESS_PRIVATE nor /* Returns EINVAL if PSHARED is neither PTHREAD_PROCESS_PRIVATE nor
PTHREAD_PROCESS_SHARED; otherwise, returns 0 if PSHARED is supported, and PTHREAD_PROCESS_SHARED; otherwise, returns 0 if PSHARED is supported, and
ENOTSUP if not. */ ENOTSUP if not. */
static __always_inline int static __always_inline int
futex_supports_pshared (int pshared); futex_supports_pshared (int pshared)
{
if (__glibc_likely (pshared == PTHREAD_PROCESS_PRIVATE))
return 0;
else if (pshared == PTHREAD_PROCESS_SHARED)
return 0;
else
return EINVAL;
}
/* Atomically wrt other futex operations on the same futex, this blocks iff /* Atomically wrt other futex operations on the same futex, this blocks iff
the value *FUTEX_WORD matches the expected value. This is the value *FUTEX_WORD matches the expected value. This is
@ -112,7 +136,27 @@ futex_supports_pshared (int pshared);
a futex_wait call when synchronizing similar to Dekker synchronization. a futex_wait call when synchronizing similar to Dekker synchronization.
However, we make no such guarantee here. */ However, we make no such guarantee here. */
static __always_inline int static __always_inline int
futex_wait (unsigned int *futex_word, unsigned int expected, int private); futex_wait (unsigned int *futex_word, unsigned int expected, int private)
{
int err = lll_futex_timed_wait (futex_word, expected, NULL, private);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
return -err;
case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* Like futex_wait but does not provide any indication why we stopped waiting. /* Like futex_wait but does not provide any indication why we stopped waiting.
Thus, when this function returns, you have to always check FUTEX_WORD to Thus, when this function returns, you have to always check FUTEX_WORD to
@ -132,7 +176,30 @@ futex_wait_simple (unsigned int *futex_word, unsigned int expected,
/* Like futex_wait but is a POSIX cancellation point. */ /* Like futex_wait but is a POSIX cancellation point. */
static __always_inline int static __always_inline int
futex_wait_cancelable (unsigned int *futex_word, unsigned int expected, futex_wait_cancelable (unsigned int *futex_word, unsigned int expected,
int private); int private)
{
int oldtype;
oldtype = __pthread_enable_asynccancel ();
int err = lll_futex_timed_wait (futex_word, expected, NULL, private);
__pthread_disable_asynccancel (oldtype);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
return -err;
case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* Like futex_wait, but will eventually time out (i.e., stop being /* Like futex_wait, but will eventually time out (i.e., stop being
blocked) after the duration of time provided (i.e., RELTIME) has blocked) after the duration of time provided (i.e., RELTIME) has
@ -144,32 +211,134 @@ futex_wait_cancelable (unsigned int *futex_word, unsigned int expected,
*/ */
static __always_inline int static __always_inline int
futex_reltimed_wait (unsigned int* futex_word, unsigned int expected, futex_reltimed_wait (unsigned int* futex_word, unsigned int expected,
const struct timespec* reltime, int private); const struct timespec* reltime, int private)
{
int err = lll_futex_timed_wait (futex_word, expected, reltime, private);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
case -ETIMEDOUT:
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* Like futex_reltimed_wait but is a POSIX cancellation point. */ /* Like futex_reltimed_wait but is a POSIX cancellation point. */
static __always_inline int static __always_inline int
futex_reltimed_wait_cancelable (unsigned int* futex_word, futex_reltimed_wait_cancelable (unsigned int* futex_word,
unsigned int expected, unsigned int expected,
const struct timespec* reltime, int private); const struct timespec* reltime, int private)
{
int oldtype;
oldtype = LIBC_CANCEL_ASYNC ();
int err = lll_futex_timed_wait (futex_word, expected, reltime, private);
LIBC_CANCEL_RESET (oldtype);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
case -ETIMEDOUT:
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* Check whether the specified clockid is supported by /* Check whether the specified clockid is supported by
futex_abstimed_wait and futex_abstimed_wait_cancelable. */ futex_abstimed_wait and futex_abstimed_wait_cancelable. */
static __always_inline int static __always_inline int
futex_abstimed_supported_clockid (clockid_t clockid); futex_abstimed_supported_clockid (clockid_t clockid)
{
return lll_futex_supported_clockid (clockid);
}
/* Like futex_reltimed_wait, but the provided timeout (ABSTIME) is an /* Like futex_reltimed_wait, but the provided timeout (ABSTIME) is an
absolute point in time; a call will time out after this point in time. */ absolute point in time; a call will time out after this point in time. */
static __always_inline int static __always_inline int
futex_abstimed_wait (unsigned int* futex_word, unsigned int expected, futex_abstimed_wait (unsigned int* futex_word, unsigned int expected,
clockid_t clockid, clockid_t clockid,
const struct timespec* abstime, int private); const struct timespec* abstime, int private)
{
/* Work around the fact that the kernel rejects negative timeout values
despite them being valid. */
if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0)))
return ETIMEDOUT;
int err = lll_futex_clock_wait_bitset (futex_word, expected,
clockid, abstime,
private);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
case -ETIMEDOUT:
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment, unsupported
clockid or due to the timeout not being
normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* Like futex_reltimed_wait but is a POSIX cancellation point. */ /* Like futex_reltimed_wait but is a POSIX cancellation point. */
static __always_inline int static __always_inline int
futex_abstimed_wait_cancelable (unsigned int* futex_word, futex_abstimed_wait_cancelable (unsigned int* futex_word,
unsigned int expected, unsigned int expected,
clockid_t clockid, clockid_t clockid,
const struct timespec* abstime, int private); const struct timespec* abstime, int private)
{
/* Work around the fact that the kernel rejects negative timeout values
despite them being valid. */
if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0)))
return ETIMEDOUT;
int oldtype;
oldtype = __pthread_enable_asynccancel ();
int err = lll_futex_clock_wait_bitset (futex_word, expected,
clockid, abstime,
private);
__pthread_disable_asynccancel (oldtype);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
case -ETIMEDOUT:
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* Atomically wrt other futex operations on the same futex, this unblocks the /* Atomically wrt other futex operations on the same futex, this unblocks the
specified number of processes, or all processes blocked on this futex if specified number of processes, or all processes blocked on this futex if
@ -190,14 +359,26 @@ futex_abstimed_wait_cancelable (unsigned int* futex_word,
object destruction (see above); therefore, we must not report or abort object destruction (see above); therefore, we must not report or abort
on most errors. */ on most errors. */
static __always_inline void static __always_inline void
futex_wake (unsigned int* futex_word, int processes_to_wake, int private); futex_wake (unsigned int* futex_word, int processes_to_wake, int private)
/* Calls __libc_fatal with an error message. Convenience function for
concrete implementations of the futex interface. */
static __always_inline __attribute__ ((__noreturn__)) void
futex_fatal_error (void)
{ {
__libc_fatal ("The futex facility returned an unexpected error code.\n"); int res = lll_futex_wake (futex_word, processes_to_wake, private);
/* No error. Ignore the number of woken processes. */
if (res >= 0)
return;
switch (res)
{
case -EFAULT: /* Could have happened due to memory reuse. */
case -EINVAL: /* Could be either due to incorrect alignment (a bug in
glibc or in the application) or due to memory being
reused for a PI futex. We cannot distinguish between the
two causes, and one of them is correct use, so we do not
act in this case. */
return;
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
} }
#endif /* futex-internal.h */ #endif /* futex-internal.h */

255
sysdeps/unix/sysv/linux/futex-internal.h
View File

@ -1,255 +0,0 @@
/* futex operations for glibc-internal use. Linux version.
Copyright (C) 2014-2019 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
<https://www.gnu.org/licenses/>. */
#ifndef FUTEX_INTERNAL_H
#define FUTEX_INTERNAL_H
#include <sysdeps/nptl/futex-internal.h>
#include <errno.h>
#include <lowlevellock-futex.h>
#include <sysdep-cancel.h>
/* See sysdeps/nptl/futex-internal.h for documentation; this file only
contains Linux-specific comments.
The Linux kernel treats provides absolute timeouts based on the
CLOCK_REALTIME clock and relative timeouts measured against the
CLOCK_MONOTONIC clock.
We expect a Linux kernel version of 2.6.22 or more recent (since this
version, EINTR is not returned on spurious wake-ups anymore). */
/* FUTEX_SHARED is always supported by the Linux kernel. */
static __always_inline int
futex_supports_pshared (int pshared)
{
if (__glibc_likely (pshared == PTHREAD_PROCESS_PRIVATE))
return 0;
else if (pshared == PTHREAD_PROCESS_SHARED)
return 0;
else
return EINVAL;
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_wait (unsigned int *futex_word, unsigned int expected, int private)
{
int err = lll_futex_timed_wait (futex_word, expected, NULL, private);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
return -err;
case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_wait_cancelable (unsigned int *futex_word, unsigned int expected,
int private)
{
int oldtype;
oldtype = __pthread_enable_asynccancel ();
int err = lll_futex_timed_wait (futex_word, expected, NULL, private);
__pthread_disable_asynccancel (oldtype);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
return -err;
case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_reltimed_wait (unsigned int *futex_word, unsigned int expected,
const struct timespec *reltime, int private)
{
int err = lll_futex_timed_wait (futex_word, expected, reltime, private);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
case -ETIMEDOUT:
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_reltimed_wait_cancelable (unsigned int *futex_word,
unsigned int expected,
const struct timespec *reltime, int private)
{
int oldtype;
oldtype = LIBC_CANCEL_ASYNC ();
int err = lll_futex_timed_wait (futex_word, expected, reltime, private);
LIBC_CANCEL_RESET (oldtype);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
case -ETIMEDOUT:
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_abstimed_supported_clockid (clockid_t clockid)
{
return lll_futex_supported_clockid (clockid);
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_abstimed_wait (unsigned int *futex_word, unsigned int expected,
clockid_t clockid,
const struct timespec *abstime, int private)
{
/* Work around the fact that the kernel rejects negative timeout values
despite them being valid. */
if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0)))
return ETIMEDOUT;
int err = lll_futex_clock_wait_bitset (futex_word, expected,
clockid, abstime,
private);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
case -ETIMEDOUT:
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment, unsupported
clockid or due to the timeout not being
normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_abstimed_wait_cancelable (unsigned int *futex_word,
unsigned int expected,
clockid_t clockid,
const struct timespec *abstime, int private)
{
/* Work around the fact that the kernel rejects negative timeout values
despite them being valid. */
if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0)))
return ETIMEDOUT;
int oldtype;
oldtype = __pthread_enable_asynccancel ();
int err = lll_futex_clock_wait_bitset (futex_word, expected,
clockid, abstime,
private);
__pthread_disable_asynccancel (oldtype);
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
case -ETIMEDOUT:
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -EINVAL: /* Either due to wrong alignment or due to the timeout not
being normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline void
futex_wake (unsigned int *futex_word, int processes_to_wake, int private)
{
int res = lll_futex_wake (futex_word, processes_to_wake, private);
/* No error. Ignore the number of woken processes. */
if (res >= 0)
return;
switch (res)
{
case -EFAULT: /* Could have happened due to memory reuse. */
case -EINVAL: /* Could be either due to incorrect alignment (a bug in
glibc or in the application) or due to memory being
reused for a PI futex. We cannot distinguish between the
two causes, and one of them is correct use, so we do not
act in this case. */
return;
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}
#endif /* futex-internal.h */