From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:37417 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751064AbbIKGWm (ORCPT ); Fri, 11 Sep 2015 02:22:42 -0400 Subject: Patch "ARM: 8384/1: VDSO: force use of BFD linker" has been added to the 4.1-stable tree To: nathan_lynch@mentor.com, al.kochet@gmail.com, gregkh@linuxfoundation.org, rmk+kernel@arm.linux.org.uk, stefan@agner.ch Cc: , From: Date: Thu, 10 Sep 2015 23:22:36 -0700 Message-ID: <144195255618961@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled ARM: 8384/1: VDSO: force use of BFD linker to the 4.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm-8384-1-vdso-force-use-of-bfd-linker.patch and it can be found in the queue-4.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From d2b30cd4b7223a96e606dfc8120626f66d81e091 Mon Sep 17 00:00:00 2001 From: Nathan Lynch Date: Wed, 3 Jun 2015 00:41:15 +0100 Subject: ARM: 8384/1: VDSO: force use of BFD linker From: Nathan Lynch commit d2b30cd4b7223a96e606dfc8120626f66d81e091 upstream. When using a toolchain with gold as the default linker, the VDSO build fails: VDSO arch/arm/vdso/vdso.so.raw HOSTCC arch/arm/vdso/vdsomunge MUNGE arch/arm/vdso/vdso.so.dbg OBJCOPY arch/arm/vdso/vdso.so BFD: arch/arm/vdso/vdso.so: Not enough room for program headers, try linking with -N For whatever reason, ld.gold is omitting an exidx program header that ld.bfd emits, and even when I work around that, I don't get a working VDSO. For now, instead of supporting gold (which will fail to link the kernel anyway since it does not implement --pic-veneer), direct the compiler to use the traditional bfd linker. This is accomplished by using -fuse-ld, which is implemented in GCC 4.8 and later. Note: one limitation of this is that if the toolchain is configured to use gold by default, and the bfd linker is not in $PATH, the VDSO build will fail: VDSO arch/arm/vdso/vdso.so.raw collect2: fatal error: cannot find 'ld' This will happen if CROSS_COMPILE begins with a path such as /opt/bin/arm-linux-gnu- but /opt/bin is not in $PATH. This is considered an acceptable corner-case limitation and is easily worked around. Additonal note: we use cc-option instead of cc-ldoption so that -fuse-ld=bfd is placed in the command line if the compiler recognizes the option. Using cc-ldoption results in an attempt to link, which fails in the situation just described, causing -fuse-ld=bfd to be omitted and gold to be used for the VDSO link, which is what we're trying to prevent. Reported-by: Stefan Agner Signed-off-by: Nathan Lynch Signed-off-by: Russell King Cc: Alexander Kochetkov Signed-off-by: Greg Kroah-Hartman --- arch/arm/vdso/Makefile | 1 + 1 file changed, 1 insertion(+) --- a/arch/arm/vdso/Makefile +++ b/arch/arm/vdso/Makefile @@ -14,6 +14,7 @@ VDSO_LDFLAGS += -Wl,-z,max-page-size=409 VDSO_LDFLAGS += -nostdlib -shared VDSO_LDFLAGS += $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) VDSO_LDFLAGS += $(call cc-ldoption, -Wl$(comma)--build-id) +VDSO_LDFLAGS += $(call cc-option, -fuse-ld=bfd) obj-$(CONFIG_VDSO) += vdso.o extra-$(CONFIG_VDSO) += vdso.lds Patches currently in stable-queue which might be from nathan_lynch@mentor.com are queue-4.1/arm-8384-1-vdso-force-use-of-bfd-linker.patch queue-4.1/arm-8385-1-vdso-group-link-options.patch