Add elision tunables

This patch adds several new tunables to control the behavior of
elision on supported platforms[1].   Since elision now depends
on tunables, we should always *compile* with elision enabled,
and leave the code disabled, but available for runtime
selection.  This gives us *much* better compile-time testing of
the existing code to avoid bit-rot[2].

Tested on ppc, ppc64, ppc64le, s390x and x86_64.

[1] This part of the patch was initially proposed by
Paul Murphy but was "staled" because the framework have changed
since the patch was originally proposed:

https://patchwork.sourceware.org/patch/10342/

[2] This part of the patch was inititally proposed as a RFC by
Carlos O'Donnell.  Make sense to me integrate this on the patch:

https://sourceware.org/ml/libc-alpha/2017-05/msg00335.html

	* elf/dl-tunables.list: Add elision parameters.
	* manual/tunables.texi: Add entries about elision tunable.
	* sysdeps/unix/sysv/linux/powerpc/elision-conf.c:
	Add callback functions to dynamically enable/disable elision.
	Add multiple callbacks functions to set elision parameters.
	Deleted __libc_enable_secure check.
	* sysdeps/unix/sysv/linux/s390/elision-conf.c: Likewise.
	* sysdeps/unix/sysv/linux/x86/elision-conf.c: Likewise.
	* configure: Regenerated.
	* configure.ac: Option enable_lock_elision was deleted.
	* config.h.in: ENABLE_LOCK_ELISION flag was deleted.
	* config.make.in: Remove references to enable_lock_elision.
	* manual/install.texi: Elision configure option was removed.
	* INSTALL: Regenerated to remove enable_lock_elision.
	* nptl/Makefile:
	Disable elision so it can verify error case for destroying a mutex.
	* sysdeps/powerpc/nptl/elide.h:
	Cleanup ENABLE_LOCK_ELISION check.
	Deleted macros for the case when ENABLE_LOCK_ELISION was not defined.
	* sysdeps/s390/configure: Regenerated.
	* sysdeps/s390/configure.ac: Remove references to enable_lock_elision..
	* nptl/tst-mutex8.c:
	Deleted all #ifndef ENABLE_LOCK_ELISION from the test.
	* sysdeps/powerpc/powerpc32/sysdep.h:
	Deleted all ENABLE_LOCK_ELISION checks.
	* sysdeps/powerpc/powerpc64/sysdep.h: Likewise.
	* sysdeps/powerpc/sysdep.h: Likewise.
	* sysdeps/s390/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/force-elision.h: Likewise.
	* sysdeps/unix/sysv/linux/s390/elision-conf.h: Likewise.
	* sysdeps/unix/sysv/linux/s390/force-elision.h: Likewise.
	* sysdeps/unix/sysv/linux/s390/lowlevellock.h: Likewise.
	* sysdeps/unix/sysv/linux/s390/Makefile: Remove references to
	enable-lock-elision.

Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>

4 files changed, 3 insertions, 14 deletions

diff --git a/sysdeps/powerpc/nptl/elide.h b/sysdeps/powerpc/nptl/elide.h
index 1c42814b71..06986ccbce 100644
--- a/sysdeps/powerpc/nptl/elide.h
+++ b/sysdeps/powerpc/nptl/elide.h
@@ -19,7 +19,6 @@
 #ifndef ELIDE_PPC_H
 # define ELIDE_PPC_H
 
-#ifdef ENABLE_LOCK_ELISION
 # include <htm.h>
 # include <elision-conf.h>
 
@@ -114,12 +113,4 @@ __elide_unlock (int is_lock_free)
 # define ELIDE_UNLOCK(is_lock_free) \
   __elide_unlock (is_lock_free)
 
-# else
-
-# define ELIDE_LOCK(adapt_count, is_lock_free) 0
-# define ELIDE_TRYLOCK(adapt_count, is_lock_free, write) 0
-# define ELIDE_UNLOCK(is_lock_free) 0
-
-#endif /* ENABLE_LOCK_ELISION  */
-
 #endif
diff --git a/sysdeps/powerpc/powerpc32/sysdep.h b/sysdeps/powerpc/powerpc32/sysdep.h
index 965ea43c94..1d2ff732ee 100644
--- a/sysdeps/powerpc/powerpc32/sysdep.h
+++ b/sysdeps/powerpc/powerpc32/sysdep.h
@@ -90,7 +90,7 @@ GOT_LABEL:			;					      \
   cfi_endproc;								      \
   ASM_SIZE_DIRECTIVE(name)
 
-#if ! IS_IN(rtld) && defined (ENABLE_LOCK_ELISION)
+#if ! IS_IN(rtld)
 # define ABORT_TRANSACTION \
     cmpwi    2,0;		\
     beq      1f;		\
diff --git a/sysdeps/powerpc/powerpc64/sysdep.h b/sysdeps/powerpc/powerpc64/sysdep.h
index ab5f395cfd..bff184e374 100644
--- a/sysdeps/powerpc/powerpc64/sysdep.h
+++ b/sysdeps/powerpc/powerpc64/sysdep.h
@@ -263,7 +263,7 @@ LT_LABELSUFFIX(name,_name_end): ; \
   TRACEBACK_MASK(name,mask);	\
   END_2(name)
 
-#if !IS_IN(rtld) && defined (ENABLE_LOCK_ELISION)
+#if !IS_IN(rtld)
 # define ABORT_TRANSACTION \
     cmpdi    13,0;		\
     beq      1f;		\
diff --git a/sysdeps/powerpc/sysdep.h b/sysdeps/powerpc/sysdep.h
index f07b959eee..d1a9bd9b55 100644
--- a/sysdeps/powerpc/sysdep.h
+++ b/sysdeps/powerpc/sysdep.h
@@ -21,10 +21,8 @@
  */
 #define _SYSDEPS_SYSDEP_H 1
 #include <bits/hwcap.h>
-#ifdef ENABLE_LOCK_ELISION
 #include <tls.h>
 #include <htm.h>
-#endif
 
 #define PPC_FEATURE_970 (PPC_FEATURE_POWER4 + PPC_FEATURE_HAS_ALTIVEC)
 
@@ -176,7 +174,7 @@
    we abort transaction just before syscalls.
 
    [1] Documentation/powerpc/transactional_memory.txt [Syscalls]  */
-#if !IS_IN(rtld) && defined (ENABLE_LOCK_ELISION)
+#if !IS_IN(rtld)
 # define ABORT_TRANSACTION \
   ({ 						\
     if (THREAD_GET_TM_CAPABLE ())		\