diff options
author | Vincent Ren-Wei Chen <vincentc@andestech.com> | 2017-01-17 07:31:24 +0100 |
---|---|---|
committer | Waldemar Brodkorb <wbx@openadk.org> | 2017-01-22 10:06:29 +0100 |
commit | 6af3332a4cbd1ffbc81f74759ef7c5e1a87d2e10 (patch) | |
tree | 4deae5f23fd1e2664f21c09dfb57fda799dffd10 /libpthread/nptl/sysdeps/nds32/pthread_spin_lock.c | |
parent | 82af21a60bc6e53dd92c1c140f20179d2ae4ad40 (diff) |
nds32: add NPTL/TLS, *context function, libm changes and code cleanup
This commit includes following features.
1. Support NPTL/TLS
2. Add libm function which is used to handle FP rounding and excpetions
(ex: fclrexcpt,fedisblxcpti,feenablxcpt... )
3. Add *context function for operating user context
(ex: setcontext,getcontext,makecontext... )
4. Change the return flow from signal handler
5. Cleanup of old code
The testsuite only has 2 errors, tst-cpuclock1 and tst-cputimer1,
which are related to timing accuracy. (math and locale tests are disabled)
Signed-off-by: Vincent Ren-Wei Chen <vincentc@andestech.com>
Diffstat (limited to 'libpthread/nptl/sysdeps/nds32/pthread_spin_lock.c')
-rw-r--r-- | libpthread/nptl/sysdeps/nds32/pthread_spin_lock.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/libpthread/nptl/sysdeps/nds32/pthread_spin_lock.c b/libpthread/nptl/sysdeps/nds32/pthread_spin_lock.c new file mode 100644 index 000000000..cec3acbc6 --- /dev/null +++ b/libpthread/nptl/sysdeps/nds32/pthread_spin_lock.c @@ -0,0 +1,65 @@ +/* pthread_spin_lock -- lock a spin lock. Generic version. + Copyright (C) 2012-2016 Free Software Foundation, Inc. + + 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 <atomic.h> +#include "pthreadP.h" + +/* A machine-specific version can define SPIN_LOCK_READS_BETWEEN_CMPXCHG + to the number of plain reads that it's optimal to spin on between uses + of atomic_compare_and_exchange_val_acq. If spinning forever is optimal + then use -1. If no plain reads here would ever be optimal, use 0. */ +#define SPIN_LOCK_READS_BETWEEN_CMPXCHG 1000 + +int +pthread_spin_lock (pthread_spinlock_t *lock) +{ + /* atomic_exchange usually takes less instructions than + atomic_compare_and_exchange. On the other hand, + atomic_compare_and_exchange potentially generates less bus traffic + when the lock is locked. + We assume that the first try mostly will be successful, and we use + atomic_exchange. For the subsequent tries we use + atomic_compare_and_exchange. */ + if (atomic_exchange_acq (lock, 1) == 0) + return 0; + + do + { + /* The lock is contended and we need to wait. Going straight back + to cmpxchg is not a good idea on many targets as that will force + expensive memory synchronizations among processors and penalize other + running threads. + On the other hand, we do want to update memory state on the local core + once in a while to avoid spinning indefinitely until some event that + will happen to update local memory as a side-effect. */ + if (SPIN_LOCK_READS_BETWEEN_CMPXCHG >= 0) + { + int wait = SPIN_LOCK_READS_BETWEEN_CMPXCHG; + + while (*lock != 0 && wait > 0) + --wait; + } + else + { + while (*lock != 0) + ; + } + } + while (atomic_compare_and_exchange_val_acq (lock, 1, 0) != 0); + + return 0; +} |