Re: [PATCH v2 00/12] Cross-compilation

[Jan Kiszka <jan.kiszka@web.de>]

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On 2018-06-28 10:27, Alexander Smirnov wrote:
> Hi all,
> 
> [NOTE]
>   Cover letter is too long, so I don't expect that you read it all. So I'd
> like to start with this message to avoid possible question. :-) This series
> has intersection with SDK one, so it should be rebased after SDK is applied
> to next. Thanks!
> [/NOTE]
> 
> here is the second version of cross-compilation support.
> This version adds support for cross-compiling stretch-armhf target.
> 
> What's new here:
>  - Build dependencies are resolved automatically, so isar-image-base could be
>    built using cross-compilation only (libhello, example-hello, example-raw)
>  - Linux kernel could be also cross-compiled now for arm
> 
> Test scenarios:
> 1. Build isar-image-base:
>  - Set variable in local.conf ISAR_CROSS_COMPILE to "1"
>  - Edit recipes: libhello and example-hello and replace
>    "inherit dpkg" by "inherit dpkg-cross"
>  - Build using "bitbake multiconfig:qemuarm-stretch:isar-image-base"
>  - With cross-compilation the image is generated twice faster
> 
> 2. Build arm kernel:
>  - Set variable in local.conf ISAR_CROSS_COMPILE to "1"
>  - There is no default arm config, so I derived the one from linux-cip
>    tree: "zx_config" and add it to recipe
>  - Build it "bitbake multiconfig:qemuarm-stretch:linux-cip"
>  - Aftewards I have the following packages:
>    * linux-image-4.4.112-cip18_4.4.112-cip18-1_armhf.deb
>    * linux-image-4.4.112-cip18-dbg_4.4.112-cip18-1_armhf.deb
>    * linux-headers-4.4.112-cip18_4.4.112-cip18-1_armhf.deb
>  - The compilation tooks me about 2-3 minutes. Much faster than in QEMU
> 
> Issue:
> 1. No support for jessie. The main issue here, that jessie doesn't have
>    armhf compiler in default apt. Official wiki asks you to use embian
>    apt to get it
> 2. mk-build-deps has two params: --host-arch, --cross-arch. But they seem
>    to work incorrectly. If set both of them in deps list I got unexisting
>    packages. Now I use --host-arch only and it works good. I want to check
>    this in buster and then probably ask Debian community reagrding this
> 3. i386 architecture for now is not considered as a target for cross
>    compilation
> 4. Currently libhello and example-hello applications have hardcoded native
>    compilation (inherit dpkg). This should be reworked to depend on
>    ISAR_CROSS_COMPILE variable
> 
> Huh, no more ideas, let's start with this.

I've started to play with this series (on top of next before the SDK
series got merged).

Setup:
 - https://github.com/siemens/jailhouse-images
 - KAS_TARGET=multiconfig:orangepi-zero-jailhouse:xradio ./build-images.sh

Findings:
 - Kernel build works
 - Module build does not yet. So I've hacked this in:

---8<---
diff --git a/meta/recipes-kernel/linux-module/files/debian/control b/meta/recipes-kernel/linux-module/files/debian/control
index 1ee634c..e4af37e 100644
--- a/meta/recipes-kernel/linux-module/files/debian/control
+++ b/meta/recipes-kernel/linux-module/files/debian/control
@@ -2,7 +2,7 @@ Source: @PN@
 Section: kernel
 Priority: optional
 Standards-Version: 3.9.6
-Build-Depends: linux-headers-@KERNEL_NAME@
+Build-Depends: linux-headers-@KERNEL_NAME@:amd64
 Maintainer: ISAR project <isar-users@googlegroups.com>
 
 Package: @PN@
diff --git a/meta/recipes-kernel/linux-module/module.inc b/meta/recipes-kernel/linux-module/module.inc
index 3075f44..86776c3 100644
--- a/meta/recipes-kernel/linux-module/module.inc
+++ b/meta/recipes-kernel/linux-module/module.inc
@@ -15,7 +15,7 @@ SRC_URI += "file://debian/"
 
 AUTOLOAD ?= "0"
 
-inherit dpkg
+inherit dpkg-cross
 
 dpkg_runbuild_prepend() {
     cp -r ${WORKDIR}/debian ${S}/
---8<---

   An interesting pattern is that I had to add the host architecture to
   the cross-built kernel headers package, or it would not have been
   found. This will be needed again below.

   Still, modules don't built, we also need to feed in ARCH=<kernel-
   target-arch> to the build. Didn't hack that up so far.

 - This, well, interesting package I was able to "cross"-compile as
   well:

   https://github.com/siemens/jailhouse-images/blob/master/recipes-core/non-root-initramfs/non-root-initramfs_2018.05.bb

   It required the following change (beside "inherit dpkg-cross"):

---8<---
diff --git a/recipes-core/non-root-initramfs/files/debian/control b/recipes-core/non-root-initramfs/files/debian/control
index b57ee83..f5eeef1 100644
--- a/recipes-core/non-root-initramfs/files/debian/control
+++ b/recipes-core/non-root-initramfs/files/debian/control
@@ -2,7 +2,7 @@ Source: non-root-initramfs
 Section: misc
 Priority: optional
 Standards-Version: 3.9.6
-Build-Depends: build-essential, wget, cpio, unzip, rsync, python, bc
+Build-Depends: build-essential:amd64, wget, cpio, unzip, rsync, python:amd64, bc
 Maintainer: Jan Kiszka <jan.kiszka@siemens.com>
 
 Package: non-root-initramfs
---8<---

   Again, dependency installation failed without explicit host arch
   specification for the two packages, but this time they come from
   upstream. Any idea why? Obviously, this hack breaks native
   compilation now.

That said, I'm excited to see this nice progress. I suspect we will
quickly sort the issues above out as well, and then more recipes - and
the whole jailhouse-images - will be cross-buildable.

Thanks,
Jan


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