From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:12621 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727348AbeJKDWX (ORCPT ); Wed, 10 Oct 2018 23:22:23 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5B57B7F6C8 for ; Wed, 10 Oct 2018 19:58:42 +0000 (UTC) From: Eric Sandeen Subject: [PATCH] xfsprogs: remove retpoline support Message-ID: <06935570-ac17-776d-0a9c-cd9158a01922@redhat.com> Date: Wed, 10 Oct 2018 14:58:40 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: linux-xfs Cc: Florian Weimer When it came up that xfsprogs was using retpolines by default, the gcc folks inside Red Hat expressed ... alarm. I'm not sure of all the details, but I think the concern was that userspace support for this is not really quite baked. Unless/until there is a demonstrated side-channel which would warrant retpolines here, let's just remove it for now. Cc: Florian Weimer Signed-off-by: Eric Sandeen --- Getting this on the list so we can have a discussion with people who understand the issues better than I do ... diff --git a/configure.ac b/configure.ac index 5fdf78e..41f1209 100644 --- a/configure.ac +++ b/configure.ac @@ -227,7 +227,6 @@ if test "$enable_lto" = "yes" && test "$have_lto" != "yes"; then AC_MSG_ERROR([LTO not supported by compiler.]) fi -AC_PACKAGE_CHECK_RETPOLINE AC_CHECK_SIZEOF([long]) AC_CHECK_SIZEOF([char *]) AC_TYPE_UMODE_T diff --git a/include/builddefs.in b/include/builddefs.in index f7d39a4..fe529c6 100644 --- a/include/builddefs.in +++ b/include/builddefs.in @@ -166,13 +166,6 @@ LIBICU_CFLAGS = @libicu_CFLAGS@ SANITIZER_CFLAGS += @addrsan_cflags@ @threadsan_cflags@ @ubsan_cflags@ SANITIZER_LDFLAGS += @addrsan_ldflags@ @threadsan_ldflags@ @ubsan_ldflags@ -# Enable retpolines if available -HAVE_RETPOLINE = @have_retpoline@ -ifeq ($(HAVE_RETPOLINE),yes) -OPTIMIZER += @retpoline_cflags@ -LOADERFLAGS += @retpoline_ldflags@ -endif - # Use special ar/ranlib wrappers if we have lto HAVE_LTO = @have_lto@ ifeq ($(HAVE_LTO),yes) diff --git a/m4/package_libcdev.m4 b/m4/package_libcdev.m4 index 0a6b514..52ddac2 100644 --- a/m4/package_libcdev.m4 +++ b/m4/package_libcdev.m4 @@ -446,25 +446,3 @@ AC_DEFUN([AC_PACKAGE_CHECK_LTO], AC_SUBST(lto_cflags) AC_SUBST(lto_ldflags) ]) - -AC_DEFUN([AC_PACKAGE_CHECK_RETPOLINE], - [ AC_MSG_CHECKING([if C compiler supports retpoline]) - OLD_CFLAGS="$CFLAGS" - OLD_LDFLAGS="$LDFLAGS" - RETPOLINE_FLAGS="-mindirect-branch=thunk" - CFLAGS="$CFLAGS $RETPOLINE_FLAGS" - LDFLAGS="$LDFLAGS $RETPOLINE_FLAGS" - AC_LINK_IFELSE([AC_LANG_PROGRAM([])], - [AC_MSG_RESULT([yes])] - [retpoline_cflags=$RETPOLINE_FLAGS] - [retpoline_ldflags=$RETPOLINE_FLAGS], - [AC_MSG_RESULT([no])]) - if test -n "$retpoline_cflags"; then - have_retpoline=yes - fi - CFLAGS="${OLD_CFLAGS}" - LDFLAGS="${OLD_LDFLAGS}" - AC_SUBST(have_retpoline) - AC_SUBST(retpoline_cflags) - AC_SUBST(retpoline_ldflags) - ])