From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaro Koskinen Subject: Re: [PATCH] mk: pass CROSS_COMPILE when compiling kernel modules Date: Fri, 7 Mar 2014 15:32:27 +0200 Message-ID: <20140307133226.GV15431@ak-desktop.emea.nsn-net.net> References: <1391791458-17601-1-git-send-email-aaro.koskinen@nsn.com> <2031701.DtHZU1GqtL@x220> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: dev-VfR2kkLFssw@public.gmane.org To: Thomas Monjalon Return-path: Content-Disposition: inline In-Reply-To: <2031701.DtHZU1GqtL@x220> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" Hi, On Tue, Feb 25, 2014 at 10:55:36PM +0100, Thomas Monjalon wrote: > 07/02/2014 18:44, Aaro Koskinen : > > Pass CROSS_COMPILE to the kernel build system when compiling kernel > > modules. Although we export CC etc. the top level kernel Makefile will > > override the environment. As a result it will end up using wrong tools > > if cross-compilation is desired but CROSS_COMPILE is not set. > > > > Signed-off-by: Aaro Koskinen > > Could you explain why it's needed ? > In a basic test, CC=$(CROSS)gcc in rte.vars.mk seems sufficient. If you compile on 32-bit host to 64-bit target, the build fails with errors such as: [...]include/linux/kernfs.h:331:1: note: expected 'const char *' but argument is of type 'const unsigned char *' kernfs_find_and_get(struct kernfs_node *kn, const char *name) ^ cc1: all warnings being treated as errors Build with V=1 shows that following appears in the command line when compiling the kernel modules: -isystem /usr/lib/gcc/i486-linux-gnu/4.8/include With the patch this will be corrected to point to my target's sysroot: -isystem /foo/bar/lib/gcc/x86_64-linux-gnu/4.8.2/include And the build succeeds without any warnings. A.