6129f046f7
When entering the guest we take a lock to ensure that nobody else messes with our TB chaining while we're doing it. If we get a segfault inside that code, we manage to work on, but will not unlock the lock. This patch forces unlocking of that lock in the segv handler. I'm not sure this is the right approach though. Maybe we should rather make sure we don't segfault in the code? I would greatly appreciate someone more intelligible than me to look at this :). Example code to trigger this is at: http://csgraf.de/tmp/conftest.c Reported-by: Fabio Erculiani <lxnay@sabayon.org> Signed-off-by: Alexander Graf <agraf@suse.de>
60 lines
1.8 KiB
C
60 lines
1.8 KiB
C
/*
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* Copyright (c) 2003 Fabrice Bellard
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*
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* This 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 of the License, or (at your option) any later version.
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*
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* This 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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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>
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*/
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/* configure guarantees us that we have pthreads on any host except
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* mingw32, which doesn't support any of the user-only targets.
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* So we can simply assume we have pthread mutexes here.
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*/
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#if defined(CONFIG_USER_ONLY)
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#include <pthread.h>
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#define spin_lock pthread_mutex_lock
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#define spin_unlock pthread_mutex_unlock
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static inline void spin_unlock_safe(pthread_mutex_t *lock)
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{
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/* unlocking an unlocked mutex results in undefined behavior */
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pthread_mutex_trylock(lock);
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pthread_mutex_unlock(lock);
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}
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#define spinlock_t pthread_mutex_t
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#define SPIN_LOCK_UNLOCKED PTHREAD_MUTEX_INITIALIZER
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#else
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/* Empty implementations, on the theory that system mode emulation
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* is single-threaded. This means that these functions should only
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* be used from code run in the TCG cpu thread, and cannot protect
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* data structures which might also be accessed from the IO thread
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* or from signal handlers.
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*/
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typedef int spinlock_t;
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#define SPIN_LOCK_UNLOCKED 0
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static inline void spin_lock(spinlock_t *lock)
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{
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}
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static inline void spin_unlock(spinlock_t *lock)
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{
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}
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static inline void spin_unlock_safe(spinlock_t *lock)
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{
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}
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#endif
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