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e921c89e01
Some SPE opcodes clashes with some recent PowerISA opcodes and until recently gas did not complain about it. However binutils recently changed it and now VLE configured gas does not support to assembler some instruction that might class with VLE (HTM for instance). It also does not help that glibc build hardware lock elision support as default (regardless of assembler support). Although runtime will not actually enables TLE on SPE hardware (since kernel will not advertise it), I see little advantage on adding HTM support on SPE built glibc. SPE uses an incompatible ABI which does not allow share the same build with default powerpc and HTM code slows down SPE without any benefict. This patch fixes it by only building HTM when SPE configuration is not used. Checked with a powerpc-linux-gnuspe build. I also did some sniff tests on a e500 hardware without any issue. [BZ #22926] * sysdeps/powerpc/powerpc32/sysdep.h (ABORT_TRANSACTION_IMPL): Define empty for __SPE__. * sysdeps/powerpc/sysdep.h (ABORT_TRANSACTION): Likewise. * sysdeps/unix/sysv/linux/powerpc/elision-lock.c (__lll_lock_elision): Do not build hardware transactional code for __SPE__. * sysdeps/unix/sysv/linux/powerpc/elision-trylock.c (__lll_trylock_elision): Likewise. * sysdeps/unix/sysv/linux/powerpc/elision-unlock.c (__lll_unlock_elision): Likewise.
89 lines
2.6 KiB
C
89 lines
2.6 KiB
C
/* elision-lock.c: Elided pthread mutex lock.
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Copyright (C) 2015-2018 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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#include <stdio.h>
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#include <pthread.h>
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#include <pthreadP.h>
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#include <lowlevellock.h>
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#include <elision-conf.h>
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#include "htm.h"
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#if !defined(LLL_LOCK) && !defined(EXTRAARG)
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/* Make sure the configuration code is always linked in for static
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libraries. */
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#include "elision-conf.c"
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#endif
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#ifndef EXTRAARG
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# define EXTRAARG
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#endif
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#ifndef LLL_LOCK
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# define LLL_LOCK(a,b) lll_lock(a,b), 0
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#endif
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#define aconf __elision_aconf
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/* Adaptive lock using transactions.
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By default the lock region is run as a transaction, and when it
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aborts or the lock is busy the lock adapts itself. */
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int
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__lll_lock_elision (int *lock, short *adapt_count, EXTRAARG int pshared)
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{
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#ifndef __SPE__
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/* adapt_count is accessed concurrently but is just a hint. Thus,
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use atomic accesses but relaxed MO is sufficient. */
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if (atomic_load_relaxed (adapt_count) > 0)
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{
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goto use_lock;
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}
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for (int i = aconf.try_tbegin; i > 0; i--)
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{
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if (__libc_tbegin (0))
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{
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if (*lock == 0)
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return 0;
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/* Lock was busy. Fall back to normal locking. */
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__libc_tabort (_ABORT_LOCK_BUSY);
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}
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else
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{
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/* A persistent failure indicates that a retry will probably
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result in another failure. Use normal locking now and
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for the next couple of calls. */
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if (_TEXASRU_FAILURE_PERSISTENT (__builtin_get_texasru ()))
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{
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if (aconf.skip_lock_internal_abort > 0)
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atomic_store_relaxed (adapt_count,
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aconf.skip_lock_internal_abort);
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goto use_lock;
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}
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}
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}
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/* Fall back to locks for a bit if retries have been exhausted */
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if (aconf.try_tbegin > 0 && aconf.skip_lock_out_of_tbegin_retries > 0)
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atomic_store_relaxed (adapt_count,
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aconf.skip_lock_out_of_tbegin_retries);
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use_lock:
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#endif
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return LLL_LOCK ((*lock), pshared);
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}
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