glibc/sysdeps/unix/sysv/linux/powerpc/elision-lock.c
Zack Weinberg a053e87849
Remove support for PowerPC SPE extension (powerpc*-*-*gnuspe*).
GCC 9 dropped support for the SPE extensions to PowerPC, which means
powerpc*-*-*gnuspe* configurations are no longer buildable with that
compiler.  This ISA extension was peculiar to the “e500” line of
embedded PowerPC chips, which, as far as I can tell, are no longer
being manufactured, so I think we should follow suit.

This patch was developed by grepping for “e500”, “__SPE__”, and
“__NO_FPRS__”, and may not eliminate every vestige of SPE support.
Most uses of __NO_FPRS__ are left alone, as they are relevant to
normal embedded PowerPC with soft-float.

        * sysdeps/powerpc/preconfigure: Error out on powerpc-*-*gnuspe*
        host type.
        * scripts/build-many-glibcs.py: Remove powerpc-*-linux-gnuspe
        and powerpc-*-linux-gnuspe-e500v1 from list of build configurations.

        * sysdeps/powerpc/powerpc32/e500: Recursively delete.
        * sysdeps/unix/sysv/linux/powerpc/powerpc32/e500: Recursively delete.
        * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/context-e500.h:
        Delete.

        * sysdeps/powerpc/fpu_control.h: Remove SPE variant.
        Issue an #error if used with a compiler in SPE-float mode.
        * sysdeps/powerpc/powerpc32/__longjmp_common.S
        * sysdeps/powerpc/powerpc32/setjmp_common.S
        * sysdeps/unix/sysv/linux/powerpc/powerpc32/getcontext-common.S
        * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/getcontext.S
        * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/setcontext.S
        * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/swapcontext.S
        * sysdeps/unix/sysv/linux/powerpc/powerpc32/setcontext-common.S
        * sysdeps/unix/sysv/linux/powerpc/powerpc32/swapcontext-common.S:
        Remove code to preserve SPE register state.

        * sysdeps/unix/sysv/linux/powerpc/elision-lock.c
        * sysdeps/unix/sysv/linux/powerpc/elision-trylock.c
        * sysdeps/unix/sysv/linux/powerpc/elision-unlock.c
        Remove __SPE__ ifndefs.
2019-05-22 10:05:40 -04:00

87 lines
2.6 KiB
C

/* elision-lock.c: Elided pthread mutex lock.
Copyright (C) 2015-2019 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
<http://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <pthread.h>
#include <pthreadP.h>
#include <lowlevellock.h>
#include <elision-conf.h>
#include "htm.h"
#if !defined(LLL_LOCK) && !defined(EXTRAARG)
/* Make sure the configuration code is always linked in for static
libraries. */
#include "elision-conf.c"
#endif
#ifndef EXTRAARG
# define EXTRAARG
#endif
#ifndef LLL_LOCK
# define LLL_LOCK(a,b) lll_lock(a,b), 0
#endif
#define aconf __elision_aconf
/* Adaptive lock using transactions.
By default the lock region is run as a transaction, and when it
aborts or the lock is busy the lock adapts itself. */
int
__lll_lock_elision (int *lock, short *adapt_count, EXTRAARG int pshared)
{
/* adapt_count is accessed concurrently but is just a hint. Thus,
use atomic accesses but relaxed MO is sufficient. */
if (atomic_load_relaxed (adapt_count) > 0)
{
goto use_lock;
}
for (int i = aconf.try_tbegin; i > 0; i--)
{
if (__libc_tbegin (0))
{
if (*lock == 0)
return 0;
/* Lock was busy. Fall back to normal locking. */
__libc_tabort (_ABORT_LOCK_BUSY);
}
else
{
/* A persistent failure indicates that a retry will probably
result in another failure. Use normal locking now and
for the next couple of calls. */
if (_TEXASRU_FAILURE_PERSISTENT (__builtin_get_texasru ()))
{
if (aconf.skip_lock_internal_abort > 0)
atomic_store_relaxed (adapt_count,
aconf.skip_lock_internal_abort);
goto use_lock;
}
}
}
/* Fall back to locks for a bit if retries have been exhausted */
if (aconf.try_tbegin > 0 && aconf.skip_lock_out_of_tbegin_retries > 0)
atomic_store_relaxed (adapt_count,
aconf.skip_lock_out_of_tbegin_retries);
use_lock:
return LLL_LOCK ((*lock), pshared);
}