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Re: [PATCH 1/3] PowerPC: Add the low level infrastructure for pthreads
- From: Will Schmidt <will_schmidt at vnet dot ibm dot com>
- To: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
- Cc: libc-alpha at sourceware dot org, Segher Boessenkool <segher at kernel dot crashing dot org>
- Date: Wed, 10 Dec 2014 13:13:58 -0600
- Subject: Re: [PATCH 1/3] PowerPC: Add the low level infrastructure for pthreads
- Authentication-results: sourceware.org; auth=none
- References: <545CFD9F dot 5040004 at linux dot vnet dot ibm dot com> <545D080D dot 3090006 at linux dot vnet dot ibm dot com> <545D1DDE dot 2060908 at linux dot vnet dot ibm dot com> <20141108030534 dot GA24941 at gate dot crashing dot org> <54612C12 dot 5040102 at linux dot vnet dot ibm dot com>
- Reply-to: will_schmidt at vnet dot ibm dot com
On Mon, 2014-11-10 at 19:20 -0200, Adhemerval Zanella wrote:
> On 08-11-2014 01:05, Segher Boessenkool wrote:
> > On Fri, Nov 07, 2014 at 05:30:38PM -0200, Adhemerval Zanella wrote:
<snip>
> Thanks, I have updated the patch. Tested on a power8 with GCC 4.9 (that have
> support for HTM builtins) and GCC 4.8 (which does not).
Code-wise, only point of real concern is in elision-lock.c, where i see
what looks like a dangling zero. A few cosmetic bits, and
clarification questions throughout.
review/commentary/questions sprinkled below.
(review of part 2,3 are in the queue).
Thanks,
-Will
> diff --git a/sysdeps/unix/sysv/linux/powerpc/Makefile b/sysdeps/unix/sysv/linux/powerpc/Makefile
> index e660736..dd5d3bc 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/Makefile
> +++ b/sysdeps/unix/sysv/linux/powerpc/Makefile
> @@ -32,4 +32,6 @@ endif
>
> ifeq ($(subdir),nptl)
> libpthread-routines += sysdep
> +libpthread-sysdep_routines += elision-lock elision-unlock elision-timed \
> + elision-trylock
> endif
This seems to match x86 and s390 changes, so looks oK.
> diff --git a/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h b/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h
> index 4e9c518..396a3d9 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h
> +++ b/sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h
> @@ -90,14 +90,23 @@ typedef union
> binary compatibility. */
> int __kind;
> #if __WORDSIZE == 64
> - int __spins;
> + short __spins;
> + short __elision;
> __pthread_list_t __list;
> # define __PTHREAD_MUTEX_HAVE_PREV 1
> +# define __PTHREAD_SPINS 0, 0
> #else
> unsigned int __nusers;
> __extension__ union
> {
> - int __spins;
> + struct
> + {
> + short __espins;
> + short __elision;
> +# define __spins __elision_data.__espins
> +# define __elision __elision_data.__elision
> +# define __PTHREAD_SPINS { 0, 0 }
> + } __elision_data;
> __pthread_slist_t __list;
> };
> #endif
> @@ -106,9 +115,6 @@ typedef union
> long int __align;
> } pthread_mutex_t;
>
> -/* Mutex __spins initializer used by PTHREAD_MUTEX_INITIALIZER. */
> -#define __PTHREAD_SPINS 0
> -
This is part of " [__PTHREAD_SPINS]: Adjust to init lock elision field.
" ? From the context, and in comparison to s390 related code, I
conclude that LOCK_ELISION is always enabled for powerpc, so there is no
need for the non-pair PTHREAD_SPINS value. correct?
> typedef union
> {
> char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
> diff --git a/sysdeps/unix/sysv/linux/powerpc/elision-conf.c b/sysdeps/unix/sysv/linux/powerpc/elision-conf.c
> new file mode 100644
> index 0000000..60a7900
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/elision-conf.c
> @@ -0,0 +1,81 @@
> +/* elision-conf.c: Lock elision tunable parameters.
> + 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 "config.h"
> +#include <pthreadP.h>
> +#include <elision-conf.h>
> +#include <unistd.h>
> +#include <dl-procinfo.h>
> +
> +/* Reasonable initial tuning values, may be revised in the future.
> + This is a conservative initial value. */
> +
> +struct elision_config __elision_aconf =
> + {
> + /* How often to not attempt to use elision if a transaction aborted
> + because the lock is already acquired. Expressed in number of lock
> + acquisition attempts. */
> + .skip_lock_busy = 3,
> + /* How often to not attempt to use elision if a transaction aborted due
> + to reasons other than other threads' memory accesses. Expressed in
> + number of lock acquisition attempts. */
> + .skip_lock_internal_abort = 3,
> + /* How often to not attempt to use elision if a lock used up all retries
> + without success. Expressed in number of lock acquisition attempts. */
> + .skip_lock_out_of_tbegin_retries = 3,
> + /* How often we retry using elision if there is chance for the transaction
> + to finish execution (e.g., it wasn't aborted due to the lock being
> + already acquired. */
> + .try_tbegin = 3,
> + /* Same as SKIP_LOCK_INTERNAL_ABORT but for trylock. */
> + .skip_trylock_internal_abort = 3,
"How often to not attempt to use elision if a ..."
I'm struggling a bit with the 'how often to not' logic in the comments
here. Perhaps it's just me. :-) (Noting that it matches the s390/x86
text).
Consider something like "How many times to attempt to use elision after
a transaction has aborted..."
Actually, after looking over the aconf.* references in the code below,
this may need to be "How many times to use a non-transactional lock
after a transactional failure has occurred because ...".
> + };
> +
> +/* Force elision for all new locks. This is used to decide whether existing
> + DEFAULT locks should be automatically upgraded to elision in
Is there an actual 'upgrade' step? Perhaps "... should automatically
use elision ... "
> + pthread_mutex_lock(). Disabled for suid programs. Only used when elision
> + is available. */
> +
> +int __pthread_force_elision attribute_hidden;
> +
> +/* Initialize elison. */
elision.
(also this way in x86/s390 copies)
> +
> +static void
> +elision_init (int argc __attribute__ ((unused)),
> + char **argv __attribute__ ((unused)),
> + char **environ)
> +{
> + int elision_available = (GLRO (dl_hwcap2) & PPC_FEATURE2_HAS_HTM) ? 1 : 0;
> +#ifdef ENABLE_LOCK_ELISION
> + __pthread_force_elision = __libc_enable_secure ? 0 : elision_available;
> +#endif
> +}
> +
> +#ifdef SHARED
> +# define INIT_SECTION ".init_array"
> +# define MAYBE_CONST
> +#else
> +# define INIT_SECTION ".preinit_array"
> +# define MAYBE_CONST const
> +#endif
> +
> +void (*MAYBE_CONST __pthread_init_array []) (int, char **, char **)
> + __attribute__ ((section (INIT_SECTION), aligned (sizeof (void *)))) =
> +{
> + &elision_init
> +};
Ok
> diff --git a/sysdeps/unix/sysv/linux/powerpc/elision-conf.h b/sysdeps/unix/sysv/linux/powerpc/elision-conf.h
> new file mode 100644
> index 0000000..333226a
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/elision-conf.h
> @@ -0,0 +1,43 @@
> +/* elision-conf.h: Lock elision tunable parameters.
> + 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/>. */
> +
> +#ifndef _ELISION_CONF_H
> +#define _ELISION_CONF_H 1
> +
> +#include <pthread.h>
> +#include <time.h>
> +
> +/* Should make sure there is no false sharing on this. */
False sharing on the structure?
> +
> +struct elision_config
> +{
> + int skip_lock_busy;
> + int skip_lock_internal_abort;
> + int skip_lock_out_of_tbegin_retries;
> + int try_tbegin;
> + int skip_trylock_internal_abort;
> +};
> +
> +extern struct elision_config __elision_aconf attribute_hidden;
> +
> +extern int __pthread_force_elision attribute_hidden;
> +
> +/* Tell the test suite to test elision for this architecture. */
> +#define HAVE_ELISION 1
> +
> +#endif
Ok.
> 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 0000000..c5a4eca
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/elision-lock.c
> @@ -0,0 +1,106 @@
> +/* 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 isuficient to memory
//insufficient
> + barrier in acquire mechanism, a strong sync need to used. */
//needs or //will need
Is this comment unique to the transactional support? Assuming so, I'd
go a step further and clarify that here.
/* The arch_compare_and_exchange... requires a strong sync ... for
transactional ... */
(for future) If this could be incorporated into atomic.h with the other
implementations of arch_compare...
> +#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
Dangling zero? This seems to match x86/s390, but looks weird.
> +#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);
> +}
> diff --git a/sysdeps/unix/sysv/linux/powerpc/elision-timed.c b/sysdeps/unix/sysv/linux/powerpc/elision-timed.c
> new file mode 100644
> index 0000000..7d5de9b
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/elision-timed.c
> @@ -0,0 +1,28 @@
> +/* elision-timed.c: Lock elision timed 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 <time.h>
> +#include <elision-conf.h>
> +#include "lowlevellock.h"
> +
> +#define __lll_lock_elision __lll_timedlock_elision
> +#define EXTRAARG const struct timespec *t,
> +#undef LLL_LOCK
> +#define LLL_LOCK(a, b) lll_timedlock(a, t, b)
> +
> +#include "elision-lock.c"
Ok
> diff --git a/sysdeps/unix/sysv/linux/powerpc/elision-trylock.c b/sysdeps/unix/sysv/linux/powerpc/elision-trylock.c
> new file mode 100644
> index 0000000..60aaf90
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/elision-trylock.c
> @@ -0,0 +1,68 @@
> +/* elision-trylock.c: Lock eliding trylock for pthreads.
> + 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 <pthread.h>
> +#include <pthreadP.h>
> +#include <lowlevellock.h>
> +#include <elision-conf.h>
> +#include "htm.h"
> +
> +#define aconf __elision_aconf
> +
> +/* Try to elide a futex trylock. FUTEX is the futex variable. ADAPT_COUNT is
> + the adaptation counter in the mutex. */
> +
> +int
> +__lll_trylock_elision (int *futex, short *adapt_count)
> +{
> + /* Implement POSIX semantics by forbiding nesting elided trylocks. */
> + __builtin_tabort (_ABORT_NESTED_TRYLOCK);
> +
> + /* Only try a transaction if it's worth it. */
> + if (*adapt_count > 0)
> + {
> + (*adapt_count)--;
> + goto use_lock;
> + }
> +
> + if (__builtin_tbegin (0))
> + {
> + if (*futex == 0)
> + return 0;
> +
> + /* Lock was busy. Fall back to normal locking. */
> + __builtin_tabort (_ABORT_LOCK_BUSY);
> + }
> + else
> + {
> + if (_TEXASRU_FAILURE_PERSISTENT (__builtin_get_texasru ()))
> + {
> + /* A persistent failure indicates that a retry will probably
> + resulting in another failure. Use normal locking now and
result
> + for the next couple of calls. */
> + if (aconf.skip_trylock_internal_abort > 0)
> + *adapt_count = aconf.skip_trylock_internal_abort;
> + }
> +
> + if (aconf.skip_lock_busy > 0)
> + *adapt_count = aconf.skip_lock_busy;
> + }
> +
> +use_lock:
> + return lll_trylock (*futex);
> +}
ok.
> diff --git a/sysdeps/unix/sysv/linux/powerpc/elision-unlock.c b/sysdeps/unix/sysv/linux/powerpc/elision-unlock.c
> new file mode 100644
> index 0000000..59d46bb
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/elision-unlock.c
> @@ -0,0 +1,32 @@
> +/* elision-unlock.c: Commit an elided pthread 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 "pthreadP.h"
> +#include "lowlevellock.h"
> +#include "htm.h"
> +
> +int
> +__lll_unlock_elision(int *lock, int pshared)
> +{
> + /* When the lock was free we're in a transaction. */
> + if (*lock == 0)
> + __builtin_tend (0);
> + else
> + lll_unlock ((*lock), pshared);
> + return 0;
> +}
Ok.
> diff --git a/sysdeps/unix/sysv/linux/powerpc/force-elision.h b/sysdeps/unix/sysv/linux/powerpc/force-elision.h
> new file mode 100644
> index 0000000..38c79bf
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/force-elision.h
> @@ -0,0 +1,33 @@
> +/* force-elision.h: Automatic enabling of elision for mutexes
> + 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/>. */
> +
> +#ifdef ENABLE_LOCK_ELISION
> +/* Check for elision on this lock without upgrading. */
> +#define DO_ELISION(m) \
> + (__pthread_force_elision \
> + && (m->__data.__kind & PTHREAD_MUTEX_NO_ELISION_NP) == 0) \
Is the 'with upgrading' counterpart the 'forcing' as seen in the #define
below?
> +
> +/* Automatically enable elision for existing user lock kinds. */
> +#define FORCE_ELISION(m, s) \
> + if (__pthread_force_elision \
> + && (m->__data.__kind & PTHREAD_MUTEX_ELISION_FLAGS_NP) == 0) \
> + { \
> + mutex->__data.__kind |= PTHREAD_MUTEX_ELISION_NP; \
> + s; \
> + }
> +#endif
Ok.
> diff --git a/sysdeps/unix/sysv/linux/powerpc/htm.h b/sysdeps/unix/sysv/linux/powerpc/htm.h
> new file mode 100644
> index 0000000..b0a5ab0
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/htm.h
> @@ -0,0 +1,142 @@
> +/* Shared HTM header. Emulate transactional execution facility intrinsics for
> + compilers and assemblers that do not support the intrinsics and instructions
> + yet.
> +
> + 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/>. */
> +
> +#ifndef _HTM_H
> +#define _HTM_H 1
> +
> +#ifdef __ASSEMBLER__
> +
> +/* tbegin. */
> +.macro TBEGIN
> + .byte 0x7c,0x00,0x05,0x1d
> +.endm
> +
> +/* tend. 0 */
> +.macro TEND
> + .byte 0x7c,0x00,0x05,0x5d
> +.endm
Can these macros use .long as seen below?
> +
> +/* tabort. code */
> +.macro TABORT code
> + .byte 0x7c
> + .byte \code
> + .byte 0x07
> + .byte 0x1d
indentation
> +.endm
> +
> +/* mfspr %dst,130 */
That comment doesn't do much. But this is maybe a good spot to define
TEXASR... (here or wherever else it fits..)
"TEXASR - Transaction EXception And Summary Register".
"TEXASRU - '' '' Upper half "
> +.macro TEXASR dst
> + mfspr \dst,130
> +.endm
> +
> +#else
> +
> +#include <endian.h>
> +
> +/* Official HTM intrinsics interface matching gcc, but works
> + on older gcc compatible compilers and binutils.
GCC
> + We should somehow detect if the compiler supports it, because
> + it may be able to generate slightly better code. */
> +
> +#define TBEGIN ".long 0x7c00051d"
> +#define TEND ".long 0x7c00055d"
> +#if __BYTE_ORDER == __LITTLE_ENDIAN
> +# define TABORT ".byte 0x1d,0x07,%1,0x1d"
> +#else
> +# define TABORT ".byte 0x7c,%1,0x07,0x1d"
> +#endif
> +
> +#define __force_inline inline __attribute__((__always_inline__))
> +
> +#ifndef __HTM__
> +
> +#define _TEXASRU_EXTRACT_BITS(TEXASR,BITNUM,SIZE) \
> + (((TEXASR) >> (31-(BITNUM))) & ((1<<(SIZE))-1))
> +#define _TEXASRU_FAILURE_PERSISTENT(TEXASRU) \
> + _TEXASRU_EXTRACT_BITS(TEXASRU, 7, 1)
> +
> +static __force_inline
> +unsigned int _tbegin (void)
> +{
> + unsigned int ret;
> + asm volatile (
> + TBEGIN "\t\n"
> + "mfcr %0\t\n"
> + "rlwinm %0,%0,3,1\t\n"
> + "xori %0,%0,1\t\n"
> + : "=r" (ret) :: "cr0", "memory");
> + return ret;
> +}
> +
> +static __force_inline
> +unsigned int _tend (void)
> +{
> + unsigned int ret;
> + asm volatile (
> + TEND "\t\n"
> + "mfcr %0\t\n"
> + "rlwinm %0,%0,3,1\t\n"
> + "xori %0,%0,1\t\n"
> + : "=r" (ret) :: "cr0", "memory");
> + return ret;
> +}
> +
> +static __force_inline
> +unsigned int _tabort (unsigned int code)
> +{
> + unsigned int ret;
> + asm volatile (
> + TABORT "\t\n"
> + "mfcr %0\t\n"
> + "rlwinm %0,%0,3,1\t\n"
> + "xori %0,%0,1\t\n"
> + : "=r" (ret) : "r" (code) : "cr0", "memory");
> + return ret;
> +}
> +
> +static __force_inline
> +unsigned long _texasru (void)
> +{
> + unsigned long ret;
> + asm volatile (
> + "mfspr %0,131\t\n"
> + : "=r" (ret));
> + return ret;
> +}
> +
> +#define __builtin_tbegin(tdb) _tbegin ()
> +#define __builtin_tend(nested) _tend ()
> +#define __builtin_tabort(abortcode) _tabort (abortcode)
> +#define __builtin_get_texasru() _texasru ()
> +
> +#else
> +# include <htmintrin.h>
> +#endif /* __HTM__ */
> +
> +#endif /* __ASSEMBLER__ */
> +
> +/* Definitions used for TEXASR Failure code (bits 0:6), they need to be even
> + because tabort. always sets the first bit. */
> +#define _ABORT_LOCK_BUSY 0x3f /* Lock already used. */
> +#define _ABORT_NESTED_TRYLOCK 0x3e /* Write operation in trylock. */
> +#define _ABORT_SYSCALL 0x3d /* Syscall issued. */
> +
> +#endif
Ok. (I've not closely reviewed the inline asm above, but expect those
are correct).
> diff --git a/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h b/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h
> new file mode 100644
> index 0000000..36c8ade
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h
> @@ -0,0 +1,48 @@
> +/* PowerPC specific lock definitions.
> + 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/>. */
> +
> +#ifndef _POWERPC_LOWLEVELLOCK_H
> +#define _POWERPC_LOWLEVELLOCK_H 1
> +
> +#include <sysdeps/nptl/lowlevellock.h>
> +
> +/* Transactional lock elision definitions. */
> +extern int __lll_timedlock_elision
> + (int *futex, short *adapt_count, const struct timespec *timeout, int private)
> + attribute_hidden;
> +
> +#define lll_timedlock_elision(futex, adapt_count, timeout, private) \
> + __lll_timedlock_elision(&(futex), &(adapt_count), timeout, private)
> +
> +extern int __lll_lock_elision (int *futex, short *adapt_count, int private)
> + attribute_hidden;
> +
> +extern int __lll_unlock_elision(int *lock, int private)
> + attribute_hidden;
> +
> +extern int __lll_trylock_elision(int *lock, short *adapt_count)
> + attribute_hidden;
> +
> +#define lll_lock_elision(futex, adapt_count, private) \
> + __lll_lock_elision (&(futex), &(adapt_count), private)
> +#define lll_unlock_elision(futex, private) \
> + __lll_unlock_elision (&(futex), private)
> +#define lll_trylock_elision(futex, adapt_count) \
> + __lll_trylock_elision (&(futex), &(adapt_count))
> +
> +#endif
Ok.
> diff --git a/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_cond_lock.c b/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_cond_lock.c
> new file mode 100644
> index 0000000..aa6cf9a
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_cond_lock.c
> @@ -0,0 +1,22 @@
> +/* 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/>. */
> +
> +/* The cond lock is not actually elided yet, but we still need to handle
> + already elided locks. */
> +#include <elision-conf.h>
> +
> +#include <nptl/pthread_mutex_cond_lock.c>
Ok.
> diff --git a/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_lock.c b/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_lock.c
> new file mode 100644
> index 0000000..6fd6a98
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_lock.c
> @@ -0,0 +1,22 @@
> +/* Elided version of 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 <elision-conf.h>
> +#include <force-elision.h>
> +
> +#include <nptl/pthread_mutex_lock.c>
> diff --git a/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_timedlock.c b/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_timedlock.c
> new file mode 100644
> index 0000000..d0e6537
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_timedlock.c
> @@ -0,0 +1,22 @@
> +/* Elided version of pthread_mutex_timedlock.
> + 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 <elision-conf.h>
> +#include <force-elision.h>
> +
> +#include <nptl/pthread_mutex_timedlock.c>
> diff --git a/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_trylock.c b/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_trylock.c
> new file mode 100644
> index 0000000..ea8a8ff
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/powerpc/pthread_mutex_trylock.c
> @@ -0,0 +1,22 @@
> +/* Elided version of pthread_mutex_trylock.
> + 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 <elision-conf.h>
> +#include <force-elision.h>
> +
> +#include <nptl/pthread_mutex_trylock.c>
>
Ok.