From 485ae5dc41f96ea954643388e956b5e82c0bfe06 Mon Sep 17 00:00:00 2001
From: Jeff Squyres <jsquyres@cisco.com>
Date: Fri, 6 Apr 2018 12:02:08 -0400
Subject: [PATCH 1/2] configure: remove block on POWER 7/BE systems

We thought there was a silent data corruption issue on POWER 7/BE
systems, so we blocked building on POWER 7/BE systems altogether.  We
later figured out that it was just data hangs -- not silent data
corruption.  So in hindsight, the configure block probably wasn't
necessary -- but we didn't know it at the time.

Regardless, the hangs have now been fixed, and we're removing the
POWER 7/BE block in configure.

For more detail on the entire saga, see
https://github.com/open-mpi/ompi/issues/4349#issuecomment-374970982.

Signed-off-by: Jeff Squyres <jsquyres@cisco.com>
(cherry picked from commit 3f0ccff1b6a2378b5a290615e3920e893ff13423)
---
 configure.ac | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/configure.ac b/configure.ac
index 0be2e806ec4..6f4b732ccee 100644
--- a/configure.ac
+++ b/configure.ac
@@ -84,17 +84,6 @@ AS_IF([test "$host" != "$target"],
       [AC_MSG_WARN([Cross-compile detected])
        AC_MSG_WARN([Cross-compiling is only partially supported])
        AC_MSG_WARN([Proceed at your own risk!])])
-# Check for architectures that we explicitly no longer support
-case "${host}" in
-    powerpc-*|powerpc64-*|ppc-*)
-        AC_MSG_ERROR([Big endian PPC is no longer supported.])
-        ;;
-esac
-case "${target}" in
-    powerpc-*|powerpc64-*|ppc-*)
-        AC_MSG_ERROR([Big endian PPC is no longer supported.])
-        ;;
-esac
 
 # AC_USE_SYSTEM_EXTENSIONS alters CFLAGS (e.g., adds -g -O2)
 OPAL_VAR_SCOPE_PUSH([CFLAGS_save])

From d0ddf0d078d55557d63d20b504002c4c9390fd55 Mon Sep 17 00:00:00 2001
From: Jeff Squyres <jsquyres@cisco.com>
Date: Tue, 10 Apr 2018 10:41:10 -0700
Subject: [PATCH 2/2] NEWS/README: note that the POWER 7/BE block has been
 removed.

Also note that ARM and POWER users may experience hangs (until
https://github.com/open-mpi/ompi/issues/4563 is fixed).

Signed-off-by: Jeff Squyres <jsquyres@cisco.com>
---
 NEWS   | 11 +++++++++++
 README |  9 +++++++++
 2 files changed, 20 insertions(+)

diff --git a/NEWS b/NEWS
index f4338a6ae46..e41bb1a5610 100644
--- a/NEWS
+++ b/NEWS
@@ -55,6 +55,17 @@ included in the vX.Y.Z section and be denoted as:
    (** also appeared: A.B.C)  -- indicating that this item was previously
                                  included in release version vA.B.C.
 
+3.1.1 -- TBD
+------------
+
+Bug fixes/minor improvements:
+- Disable the POWER 7/BE block in configure.  Note that POWER 7/BE is
+  still not a supported platform, but it is no longer automatically
+  disabled.  See
+  https://github.com/open-mpi/ompi/issues/4349#issuecomment-374970982
+  for more information.
+
+
 3.1.0 -- March, 2018
 ----------------------
 
diff --git a/README b/README
index 37805680a1d..8a136c06d08 100644
--- a/README
+++ b/README
@@ -140,6 +140,15 @@ General notes
     using the clang-4.0 system compiler. A workaround is to build
     Open MPI using the GNU compiler.
 
+Platform Notes
+--------------
+
+- ARM and POWER users may experience intermittent hangs when Open MPI
+  is compiled with low optimization settings, due to an issue with our
+  atomic list implementation.  We recommend compiling with -O3
+  optimization, both for performance reasons and to avoid this hang.
+
+
 Compiler Notes
 --------------