ebuild diff with lock-elision USE and --disable-lock-elision fixes.

glibc-2.20.ebuild.diff (text/plain), 6.12 KB, created by Daniel Goertzen on 2014-09-30 18:38:24 UTC

--- /usr/portage/sys-libs/glibc/glibc-2.20.ebuild       2014-09-16 04:31:19.000000000 +0000
+++ portage/overlay/sys-libs/glibc/glibc-2.20-r99.ebuild        2014-09-30 13:44:02.588850172 +0000
@@ -30,7 +30,7 @@
 PATCH_VER="1"                                  # Gentoo patchset
 NPTL_KERN_VER=${NPTL_KERN_VER:-"2.6.32"}       # min kernel version nptl requires
 
-IUSE="debug gd hardened multilib nscd selinux systemtap profile suid vanilla crosscompile_opts_headers-only"
+IUSE="debug gd hardened multilib nscd selinux systemtap profile suid vanilla crosscompile_opts_headers-only lock-elision"
 
 # Here's how the cross-compile logic breaks down ...
 #  CTARGET - machine that will target the binaries
@@ -186,4 +186,7 @@
                        -e 's:-fstack-protector$:-fstack-protector-all:' \
                        */Makefile || die
        fi
+
+       epatch "${FILESDIR}/2.20/glibc-2.20-lock-elision-disable-fixes.patch"
+
 }
--- /usr/portage/sys-libs/glibc/files/eblits/src_configure.eblit        2014-09-18 17:01:17.000000000 +0000
+++ portage/overlay/sys-libs/glibc/files/eblits/src_configure.eblit     2014-09-30 13:39:02.660620780 +0000
@@ -46,6 +46,10 @@
                myconf+=( --enable-old-ssp-compat )
        fi
 
+       if has_version '>=sys-libs/glibc-2.20' ; then
+               myconf+=( $(use_enable lock-elision) )
+       fi
+
        [[ $(tc-is-softfloat) == "yes" ]] && myconf+=( --without-fp )
 
        if [[ $1 == "linuxthreads" ]] ; then
--- /dev/null   2014-09-09 14:59:32.131411251 +0000
+++ portage/overlay/sys-libs/glibc/files/2.20/glibc-2.20-lock-elision-disable-fixes.patch       2014-09-29 20:32:34.414889884 +0000
@@ -0,0 +1,115 @@
+ref https://sourceware.org/ml/libc-alpha/2014-09/msg00662.html
+Andreas,
+
+All lock elision enablement should be controlled by the
+.--enable-lock-elision configure option.
+
+I have already written to Andi about this, and he agreed
+that it's OK for x86_64, and is what we agreed upon at
+the global level for glibc.
+
+Would you agree that this is also OK for s390?
+
+The goal is to be able to enable or disable lock elision
+for all architectures with a single configure option.
+
+I understand that this is slightly different from what
+we do for other features that we simply detect and use.
+
+We do it this way for elision to give distributions the
+flexibility because this feature is quite new and has potential
+side-effects that perhaps might only be best enabled in a newer
+version of the distribution.
+
+It also gives users the ability to disable it if it's causing
+problems for applications that are important to their use
+cases, but that don't work well with elision.
+
+In the long term I expect that runtime tunnables will be useful
+in enabling or disabling elision on a per-application basis.
+
+OK to commit for s390?
+
[phone]  Carlos O'Donell  <[e-mail]>
+
+       * configure.ac: --enable-lock-elision enables or disables
+       all elision for locks, not just mutexes.
+       * configure: Regenerate.
+       * sysdeps/unix/sysv/linux/s390/elision-conf.c (elision_init)
+       [!ENABLE_LOCK_ELISION]: Set __pthread_force_elision to zero.
+       * sysdeps/unix/sysv/linux/x86/elision-conf.c (elision_init)
+       [!ENABLE_LOCK_ELISION]: Set __pthread_force_elision,
+       __elision_available, and __elision_aconf.retry_try_xbegin to zero.
+
+diff --git a/configure b/configure
+index 89566c5..9a9cf08 100755
+--- a/configure
++++ b/configure
+@@ -1413,7 +1413,7 @@ Optional Features:
+                           initialize __stack_chk_guard canary with a random
+                           number at program start
+   --enable-lock-elision=yes/no
+-                          Enable lock elision for pthread mutexes by default
++                          Enable hardware lock elision by default
+   --enable-add-ons[=DIRS...]
+                           configure and build add-ons in DIR1,DIR2,... search
+                           for add-ons if no parameter given
+diff --git a/configure.ac b/configure.ac
+index 82d0896..d113772 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -169,7 +169,7 @@ fi
+ 
+ AC_ARG_ENABLE([lock-elision],
+             AC_HELP_STRING([--enable-lock-elision[=yes/no]],
+-                           [Enable lock elision for pthread mutexes by default]),
++                           [Enable hardware lock elision by default]),
+             [enable_lock_elision=$enableval],
+             [enable_lock_elision=no])
+ AC_SUBST(enable_lock_elision)
+diff --git a/sysdeps/unix/sysv/linux/s390/elision-conf.c b/sysdeps/unix/sysv/linux/s390/elision-conf.c
+index 69c0483..852433e 100644
+--- a/sysdeps/unix/sysv/linux/s390/elision-conf.c
++++ b/sysdeps/unix/sysv/linux/s390/elision-conf.c
+@@ -60,11 +60,16 @@ elision_init (int argc __attribute__ ((unused)),
+             char **argv  __attribute__ ((unused)),
+             char **environ)
+ {
++#ifdef ENABLE_LOCK_ELISION
+   /* Set when the CPU and the kernel supports transactional execution.
+      When false elision is never attempted.  */
+   int elision_available = (GLRO (dl_hwcap) & HWCAP_S390_TE) ? 1 : 0;
+ 
+   __pthread_force_elision = __libc_enable_secure ? 0 : elision_available;
++#else
++  /* This configuration has elision disabled.  */
++  __pthread_force_elision = 0;
++#endif
+ }
+ 
+ #ifdef SHARED
+diff --git a/sysdeps/unix/sysv/linux/x86/elision-conf.c b/sysdeps/unix/sysv/linux/x86/elision-conf.c
+index 28e48d9..abc42b7 100644
+--- a/sysdeps/unix/sysv/linux/x86/elision-conf.c
++++ b/sysdeps/unix/sysv/linux/x86/elision-conf.c
+@@ -62,12 +62,17 @@ elision_init (int argc __attribute__ ((unused)),
+             char **argv  __attribute__ ((unused)),
+             char **environ)
+ {
+-  __elision_available = HAS_RTM;
+ #ifdef ENABLE_LOCK_ELISION
++  __elision_available = HAS_RTM;
+   __pthread_force_elision = __libc_enable_secure ? 0 : __elision_available;
+-#endif
+   if (!HAS_RTM)
+-    __elision_aconf.retry_try_xbegin = 0; /* Disable elision on rwlocks */
++    __elision_aconf.retry_try_xbegin = 0; /* Disable elision on rwlocks.  */
++#else
++  /* This configuration has elision disabled.  */
++  __elision_available = 0;
++  __pthread_force_elision = 0;
++  __elision_aconf.retry_try_xbegin = 0;
++#endif
+ }
+ 
+ #ifdef SHARED