81 lines
3.0 KiB
C
81 lines
3.0 KiB
C
/* Out-of-line notification function for the GSCOPE locking mechanism.
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Copyright (C) 2007-2020 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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<https://www.gnu.org/licenses/>. */
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#include <nptl/descr.h>
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#include <futex-internal.h>
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#include <ldsodefs.h>
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#include <list.h>
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#include <lowlevellock.h>
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void
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__thread_gscope_wait (void)
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{
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lll_lock (GL (dl_stack_cache_lock), LLL_PRIVATE);
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struct pthread *self = THREAD_SELF;
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/* Iterate over the list with system-allocated threads first. */
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list_t *runp;
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list_for_each (runp, &GL (dl_stack_used))
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{
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struct pthread *t = list_entry (runp, struct pthread, list);
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if (t == self || t->header.gscope_flag == THREAD_GSCOPE_FLAG_UNUSED)
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continue;
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int *const gscope_flagp = &t->header.gscope_flag;
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/* We have to wait until this thread is done with the global
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scope. First tell the thread that we are waiting and
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possibly have to be woken. */
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if (atomic_compare_and_exchange_bool_acq (gscope_flagp,
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THREAD_GSCOPE_FLAG_WAIT,
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THREAD_GSCOPE_FLAG_USED))
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continue;
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do
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futex_wait_simple ((unsigned int *) gscope_flagp,
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THREAD_GSCOPE_FLAG_WAIT, FUTEX_PRIVATE);
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while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT);
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}
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/* Now the list with threads using user-allocated stacks. */
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list_for_each (runp, &GL (dl_stack_user))
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{
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struct pthread *t = list_entry (runp, struct pthread, list);
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if (t == self || t->header.gscope_flag == THREAD_GSCOPE_FLAG_UNUSED)
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continue;
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int *const gscope_flagp = &t->header.gscope_flag;
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/* We have to wait until this thread is done with the global
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scope. First tell the thread that we are waiting and
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possibly have to be woken. */
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if (atomic_compare_and_exchange_bool_acq (gscope_flagp,
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THREAD_GSCOPE_FLAG_WAIT,
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THREAD_GSCOPE_FLAG_USED))
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continue;
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do
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futex_wait_simple ((unsigned int *) gscope_flagp,
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THREAD_GSCOPE_FLAG_WAIT, FUTEX_PRIVATE);
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while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT);
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}
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lll_unlock (GL (dl_stack_cache_lock), LLL_PRIVATE);
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}
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