Re: [dpdk-dev] [dpdk-stable] [PATCH v5] eal: arm: fix out of tree build

[Ruifeng Wang <Ruifeng.Wang@arm.com>]

> -----Original Message-----
> From: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>
> Sent: Friday, June 11, 2021 6:28 PM
> To: Bruce Richardson <bruce.richardson@intel.com>; David Marchand
> <david.marchand@redhat.com>
> Cc: Jan Viktorin <viktorin@rehivetech.com>; Ruifeng Wang
> <Ruifeng.Wang@arm.com>; jerinj@marvell.com; dev <dev@dpdk.org>;
> dpdk stable <stable@dpdk.org>; kosar@rehivetech.com; Phil Yang
> <Phil.Yang@arm.com>; Joyce Kong <Joyce.Kong@arm.com>
> Subject: Re: [dpdk-stable] [PATCH v5] eal: arm: fix out of tree build
> 
> Hi there,
> 
> On Fri, 2021-06-11 at 10:59 +0100, Bruce Richardson wrote:
> > On Fri, Jun 11, 2021 at 11:54:25AM +0200, David Marchand wrote:
> > > Hello Bruce,
> > >
> > > On Wed, Jun 9, 2021 at 12:18 PM Michael Pfeiffer
> > > <michael.pfeiffer@tu-ilmenau.de> wrote:
> > > >
> > > > Including various headers may fail for ARM builds with 'Platform
> > > > must be built with RTE_FORCE_INTRINSICS' if rte_config.h is not
> > > > included before. Move the error message after the includes to
> > > > ensure rte_config.h is always included.
> > > >
> > > > Fixes: de966ccdcd7f ("eal/arm: add byte order operations for ARM")
> > > > Fixes: 17d5fa0fa90d ("eal/arm: add atomic operations for ARMv7")
> > > > Fixes: d708f01b7102 ("eal/arm: add atomic operations for ARMv8")
> > > > Fixes: 2173f3333b61 ("mcslock: add MCS queued lock
> > > > implementation")
> > > > Fixes: 7860c3965483 ("eal/arm: add spinlock operations for ARM")
> > > > Fixes: ca49b92079df ("ticketlock: enable generic ticketlock on all
> > > > arch")
> > > > Cc: stable@dpdk.org
> > > > Cc: kosar@rehivetech.com
> > > > Cc: phil.yang@arm.com
> > > > Cc: joyce.kong@arm.com
> > > >
> > > > Signed-off-by: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>
> > >
> > > The header check currently compiles all headers with an implicit
> > > "-include rte_config.h".
> > > I suppose this is because it comes from the project level meson
> > > configuration.
> > >
> > > Would there be a way to detect the issue fixed by this patch?
> > >
> > I'm not convinced that there is an issue here. For DPDK compiles
> > rte_config.h must always be included first, which is why it's included
> > in the cflags reported by pkg-config. If we do want to move away from
> > having rte_config as an omnipresent first include, we need to update
> > many DPDK headers to explicitly include it.
> 
> the issue came up in our (rather large) DPDK app. Our build process uses a
> hand-crafted build system (based on ninja) for native and cross builds, i.e.
> pkg-config is not involved. It basically throws "-isystem <our-target-
> prefix>/include/dpdk" into the compiler and omits linking some of the
> prefix>DPDK libs
> not used by us.
> 
> This worked fine for us, and has no issues for x86 targets. I guess because
> most headers do include rte_config (or rte_common) at least transitively
As what I can find, no issues for x86 because it has been fixed in commit:
0d440d081ca1 ("lib: fix missing includes in exported headers")

> before doing anything else. Anyway, if you regard "-include rte_config.h" as
> the way to go, this is fine for me. Its a one-liner for us and we can probably
> drop the patch then.
> 
> Regards
> Michael