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55c11fbdb0
* descr.h (struct pthread): Move the union out of [!TLS_DTV_AT_TP], so we always define the padding space. [!TLS_DTV_AT_TP]: Give tcbhead_t field a name, `header', since GCC stopped supporting its own extensions fully. [TLS_MULTIPLE_THREADS_IN_TCB]: Put `multiple_threads' inside a wrapper struct also called `header', so `header.multiple_threads' is the field name to use on all machines. * allocatestack.c (allocate_stack): Use `header.' prefix. * sysdeps/pthread/createthread.c (create_thread): Likewise. * pthread_create.c (__pthread_create_2_1): Likewise. * sysdeps/i386/tls.h (INSTALL_NEW_DTV, THREAD_DTV): Likewise. (THREAD_SELF): Likewise. * sysdeps/x86_64/tls.h: Likewise. * sysdeps/unix/sysv/linux/i386/sysdep-cancel.h (SINGLE_THREAD_P): Likewise. * sysdeps/unix/sysv/linux/sh/sysdep-cancel.h (SINGLE_THREAD_P): Likewise. * sysdeps/unix/sysv/linux/s390/s390-64/sysdep-cancel.h (SINGLE_THREAD_P): Likewise.
165 lines
5.1 KiB
C
165 lines
5.1 KiB
C
/* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <sched.h>
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#include <setjmp.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <atomic.h>
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#include <ldsodefs.h>
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#include <tls.h>
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#define CLONE_SIGNAL (CLONE_SIGHAND | CLONE_THREAD)
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/* Unless otherwise specified, the thread "register" is going to be
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initialized with a pointer to the TCB. */
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#ifndef TLS_VALUE
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# define TLS_VALUE pd
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#endif
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#ifndef ARCH_CLONE
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# define ARCH_CLONE __clone
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#endif
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#ifndef TLS_MULTIPLE_THREADS_IN_TCB
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/* Variable set to a nonzero value if more than one thread runs or ran. */
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int __pthread_multiple_threads attribute_hidden;
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/* Pointer to the corresponding variable in libc. */
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int *__libc_multiple_threads_ptr attribute_hidden;
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#endif
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static int
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create_thread (struct pthread *pd, STACK_VARIABLES_PARMS)
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{
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#ifdef PREPARE_CREATE
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PREPARE_CREATE;
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#endif
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#ifdef TLS_TCB_AT_TP
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assert (pd->header.tcb != NULL);
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#endif
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if (__builtin_expect (THREAD_GETMEM (THREAD_SELF, report_events), 0))
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{
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/* The parent thread is supposed to report events. Check whether
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the TD_CREATE event is needed, too. */
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const int _idx = __td_eventword (TD_CREATE);
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const uint32_t _mask = __td_eventmask (TD_CREATE);
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if ((_mask & (__nptl_threads_events.event_bits[_idx]
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| pd->eventbuf.eventmask.event_bits[_idx])) != 0)
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{
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/* We have to report the new thread. Make sure the thread
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does not run far by forcing it to get a lock. We lock it
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here too so that the new thread cannot continue until we
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tell it to. */
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lll_lock (pd->lock);
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/* Create the thread. */
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if (ARCH_CLONE (start_thread_debug, STACK_VARIABLES_ARGS,
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CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGNAL |
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CLONE_SETTLS | CLONE_PARENT_SETTID |
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CLONE_CHILD_CLEARTID | CLONE_DETACHED | 0,
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pd, &pd->tid, TLS_VALUE, &pd->tid) == -1)
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/* Failed. */
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return errno;
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#ifdef TLS_MULTIPLE_THREADS_IN_TCB
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/* We now have for sure more than one thread. */
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pd->header.multiple_threads = 1;
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#else
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__pthread_multiple_threads = *__libc_multiple_threads_ptr = 1;
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#endif
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/* Now fill in the information about the new thread in
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the newly created thread's data structure. We cannot let
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the new thread do this since we don't know whether it was
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already scheduled when we send the event. */
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pd->eventbuf.eventnum = TD_CREATE;
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pd->eventbuf.eventdata = pd;
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/* Enqueue the descriptor. */
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do
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pd->nextevent = __nptl_last_event;
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while (atomic_compare_and_exchange_acq (&__nptl_last_event, pd,
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pd->nextevent) != 0);
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/* Now call the function which signals the event. */
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__nptl_create_event ();
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/* And finally restart the new thread. */
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lll_unlock (pd->lock);
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return 0;
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}
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}
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#ifdef NEED_DL_SYSINFO
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assert (THREAD_GETMEM (THREAD_SELF, header.sysinfo) == pd->header.sysinfo);
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#endif
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/* We rely heavily on various flags the CLONE function understands:
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CLONE_VM, CLONE_FS, CLONE_FILES
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These flags select semantics with shared address space and
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file descriptors according to what POSIX requires.
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CLONE_SIGNAL
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This flag selects the POSIX signal semantics.
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CLONE_SETTLS
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The sixth parameter to CLONE determines the TLS area for the
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new thread.
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CLONE_PARENT_SETTID
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The kernels writes the thread ID of the newly created thread
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into the location pointed to by the fifth parameters to CLONE.
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Note that it would be semantically equivalent to use
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CLONE_CHILD_SETTID but it is be more expensive in the kernel.
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CLONE_CHILD_CLEARTID
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The kernels clears the thread ID of a thread that has called
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sys_exit() in the location pointed to by the seventh parameter
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to CLONE.
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CLONE_DETACHED
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No signal is generated if the thread exists and it is
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automatically reaped.
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The termination signal is chosen to be zero which means no signal
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is sent. */
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if (ARCH_CLONE (start_thread, STACK_VARIABLES_ARGS,
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CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGNAL |
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CLONE_SETTLS | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID |
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CLONE_DETACHED | 0, pd, &pd->tid, TLS_VALUE, &pd->tid) == -1)
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/* Failed. */
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return errno;
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#ifdef TLS_MULTIPLE_THREADS_IN_TCB
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/* We now have for sure more than one thread. */
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THREAD_SETMEM (THREAD_SELF, header.multiple_threads, 1);
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#endif
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return 0;
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}
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