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Re: [PATCH 1/3] PowerPC: Add the low level infrastructure for pthreads


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.



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