[dpdk-users] Cross compile for ARM64 fails due to librte_vhost and pmdinfogen issues

[Hemant Agrawal]

Hi Michael,
	One of the problem, I found with Linaro gcc 4.9 toolchain for i686 (default one), that it seems to be built with older kernel headers (<3.8). This usages older linux/vhost.h file.

However, we have not observed this issue with x86_64 based toolchain on 64 bit m/c.
 https://releases.linaro.org/14.11/components/toolchain/binaries/aarch64-linux-gnu/

Regards,
Hemant

> -----Original Message-----
> From: users [mailto:users-bounces at dpdk.org] On Behalf Of Michael Wildt
> Sent: Wednesday, September 14, 2016 12:05 AM
> To: Thomas Monjalon <thomas.monjalon at 6wind.com>
> Cc: users at dpdk.org
> Subject: Re: [dpdk-users] Cross compile for ARM64 fails due to librte_vhost and
> pmdinfogen issues
> 
> Hi Thomas,
> 
> The Linaro gcc 4.9 is correct when it gets to __GNUC_MINOR__, used a test
> application. Its actually 4.9.2.
> 
> Tried a newer Linaro tool chain, turned out to be a bit more complicated since
> that does not work on RHEL6, is however a success. With Linaro 5.3 one can
> cross compile dpdk fine with no errors, though the rte_byteorder.h file still
> points to arm's version, but pmdinfogen builds.
> 
> Probably should still fix both issues just to keep the base clean.
> 
> At least I have a workaround in the interim.
> 
> Thanks for the help.
> 
> Thanks,
> Michael
> 
> 
> On Tue, Sep 13, 2016 at 11:07 AM, Thomas Monjalon
> <thomas.monjalon at 6wind.com
> > wrote:
> 
> > 2016-09-13 07:45, Michael Wildt:
> > > Hi Thomas,
> > >
> > > Appreciate the assistance. Please see inline.
> > >
> > >
> > > On Tue, Sep 13, 2016 at 5:03 AM, Thomas Monjalon <
> > thomas.monjalon at 6wind.com>
> > > wrote:
> > >
> > > > Hi,
> > > >
> > > > 2016-09-12 22:20, Michael Wildt:
> > > > > I'm attempting to cross compile DPDK on an x86 for an ARM64 target.
> > This
> > > > > fails in the following areas, using latest dpdk as of 9/12. When
> > > > compiling
> > > > > natively there are no issues.
> > > >
> > > > Your analysis below seems good.
> > > > Interestingly, I do not see such error (don't know why).
> > > > Please could you share the commands you are using?
> > > >
> > >
> > > Sure can.
> > >
> > > make config T=arm64-armv8a-linuxapp-gcc CROSS=/projects/ccxsw/
> > > toolchains/gcc-linaro-aarch64-linux-gnu-4.9-2014.09_linux/
> > bin/aarch64-linux-gnu-
> > > ARCH=arm64
> > >
> > > make T=arm64-armv8a-linuxapp-gcc CROSS=/projects/ccxsw/
> > > toolchains/gcc-linaro-aarch64-linux-gnu-4.9-2014.09_linux/
> > bin/aarch64-linux-gnu-
> > > ARCH=arm64 RTE_KERNELDIR=/projects/kernel
> > >
> > > > > - librte_vhost, fails with:
> > > > >
> > > > > /projects/dpdk_latest/lib/librte_vhost/vhost_user/virtio-
> > > > net-user.c:250:23:
> > > > > error: array subscript is above array bounds [-Werror=array-bounds]
> > > > >    rvq = dev->virtqueue[i * VIRTIO_QNUM + VIRTIO_RXQ];
> > > > [...]
> > > > > - buildtools/pmdinfogen, fails with:
> > > > >
> > > > > == Build buildtools/pmdinfogen
> > > > >   HOSTCC pmdinfogen.o
> > > > > /projects/dpdk_test_wget/dpdk-16.07/build/include/rte_byteorder.h:
> > > > > Assembler messages:
> > > > > /projects/dpdk_test_wget/dpdk-16.07/build/include/rte_
> > byteorder.h:53:
> > > > > Error: no such instruction: `rev16 %bx,%bx'
> > > > [...]
> > > > >   - The issue is due to the rte_byteorder.h file which gets
> > > > >   symlink'ed with the ARM version at the beginning of the build.
> > > > >   The pmdinfogen is always compiled for x86 thus the asm is failing.
> >
> > It is definitely something to fix.
> > In the meantime, you should be able to compile DPDK by using a more
> > recent toolchain. This error is in:
> >
> > /* fix missing __builtin_bswap16 for gcc older then 4.8 */ #if
> > !(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))
> >
> > I know you are using gcc-4.9 but maybe __GNUC_MINOR__ is wrong in yours.
> >
> >