diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/powerpc/elision-lock.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/powerpc/elision-lock.c | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/powerpc/elision-lock.c b/sysdeps/unix/sysv/linux/powerpc/elision-lock.c new file mode 100644 index 0000000000..2ce75b20b8 --- /dev/null +++ b/sysdeps/unix/sysv/linux/powerpc/elision-lock.c @@ -0,0 +1,107 @@ +/* elision-lock.c: Elided pthread mutex lock. + Copyright (C) 2014 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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 <stdio.h> +#include <pthread.h> +#include <pthreadP.h> +#include <lowlevellock.h> +#include <elision-conf.h> +#include "htm.h" + +/* PowerISA 2.0.7 Section B.5.5 defines isync to be insufficient as a + barrier in acquire mechanism for HTM operations, a strong 'sync' is + required. */ +#undef __arch_compare_and_exchange_val_32_acq +#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \ + ({ \ + __typeof (*(mem)) __tmp; \ + __typeof (mem) __memp = (mem); \ + __asm __volatile ( \ + "1: lwarx %0,0,%1" MUTEX_HINT_ACQ "\n" \ + " cmpw %0,%2\n" \ + " bne 2f\n" \ + " stwcx. %3,0,%1\n" \ + " bne- 1b\n" \ + "2: sync" \ + : "=&r" (__tmp) \ + : "b" (__memp), "r" (oldval), "r" (newval) \ + : "cr0", "memory"); \ + __tmp; \ + }) + +#if !defined(LLL_LOCK) && !defined(EXTRAARG) +/* Make sure the configuration code is always linked in for static + libraries. */ +#include "elision-conf.c" +#endif + +#ifndef EXTRAARG +# define EXTRAARG +#endif +#ifndef LLL_LOCK +# define LLL_LOCK(a,b) lll_lock(a,b), 0 +#endif + +#define aconf __elision_aconf + +/* Adaptive lock using transactions. + By default the lock region is run as a transaction, and when it + aborts or the lock is busy the lock adapts itself. */ + +int +__lll_lock_elision (int *lock, short *adapt_count, EXTRAARG int pshared) +{ + if (*adapt_count > 0) + { + (*adapt_count)--; + goto use_lock; + } + + int try_begin = aconf.try_tbegin; + while (1) + { + if (__builtin_tbegin (0)) + { + if (*lock == 0) + return 0; + /* Lock was busy. Fall back to normal locking. */ + __builtin_tabort (_ABORT_LOCK_BUSY); + } + else + { + /* A persistent failure indicates that a retry will probably + result in another failure. Use normal locking now and + for the next couple of calls. */ + if (try_begin-- <= 0 + || _TEXASRU_FAILURE_PERSISTENT (__builtin_get_texasru ())) + { + if (aconf.skip_lock_internal_abort > 0) + *adapt_count = aconf.skip_lock_internal_abort; + goto use_lock; + } + /* Same logic as above, but for for a number of temporary failures + in a row. */ + else if (aconf.skip_lock_out_of_tbegin_retries > 0 + && aconf.try_tbegin > 0) + *adapt_count = aconf.skip_lock_out_of_tbegin_retries; + } + } + +use_lock: + return LLL_LOCK ((*lock), pshared); +} |