Re: [PATCH v3 0/7] Isar cross-compilation support

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2018-07-17 17:41, Alexander Smirnov wrote:
> 
> 
> On 07/17/2018 04:38 PM, Jan Kiszka wrote:
>> On 2018-07-17 15:18, Alexander Smirnov wrote:
>>> Hi everybody,
>>>
>>> sorry for the delay, this is the third version of cross-compilation
>>> support for Isar.
>>>
>>
>> Thanks for the update!
>>
>>> Supported targets for cross-compilation:
>>>   - stretch armhf
>>>   - stretch amd64
>>>
>>> Artifacts could be cross-compiled:
>>>   - dpkg.bbclass users
>>>   - dpkg-raw.bbclass users
>>>   - kernel
>>>
>>> Known issues:
>>>   - if target and host architectures are the same, there is no need
>>>     to use host buildchroot.
>>>   - kernel module doesn't support cross-compilation. Default
>>> linux-headers
>>>     package depends from target gcc binaries. So attempt to install, for
>>>     example linux-headers-armmp, tries to install gcc:armhf, what rises
>>>     conflict with the host tools.
>>
>> Could you imagine overriding such specialties with extra rules, even if
>> package specific? Not having kernel module in the cross compilation
>> chain main cause troubles (or does it work fine to cross-build the
>> kernel and then natively build the modules?).
> 
> What I'd like to try:
> 1. Add ARM defconfig for linux-cip
> 2. Try to build example module for linux-cip for armhf
> 
> Regarding overriding default Debian kernel, ATM I don't see any
> possibilities. Just as an exercise - I tried to install
> linux-headers-armmp:
> 
> $ sudo dpkg --add-architecture armhf
> $ sudo apt-get update
> $ sudo apt-get install linux-headers-armmp
> 
> No chances here, this package pulls lots of armhf binaries that conflict
> with the host ones. The only way I see now is to manually fetch and
> unpack this package. But it's an ugly hack IMHO :-(

But maybe we can resolve that issue for self-built kernel by providing
also a compatible headers package?

> 
> Regarding hybrid mode (apps and kernel are compiled cross, modules are
> compiled natively) - this works. You could check this by trying
> cross-build for qemuarm-stretch, for example.

I suppose to opt-out a package from cross-building, I need to add
ISAR_CROSS_COMPILE = "0" to its recipe, right? Currently trying... no:

| Broken jailhouse-build-deps:arm64 Depends on
linux-headers-jailhouse-arm64:arm64 < none @un H >
|   Removing jailhouse-build-deps:arm64 because I can't find
linux-headers-jailhouse-arm64:arm64

The problem seems to be that the header package is generate as :amd64,
so I can't install it into the arm64 buildchroot. However, the cross
build also fails because it searches for :arm64 as well:

| Broken jailhouse-cross-build-deps:arm64 Depends on
linux-headers-jailhouse-arm64:arm64 < none @un H >
|   Removing jailhouse-cross-build-deps:arm64 because I can't find
linux-headers-jailhouse-arm64:arm64

By requesting :amd64 versions of the header as well as some python deps,
I'm getting further and then fail differently:

| dpkg-architecture: warning: specified GNU system type
aarch64-linux-gnu does not match CC system type x86_64-linux-gnu, try
setting a correct CC environment variable
|  dpkg-source --before-build git
| dpkg-buildpackage: info: host architecture arm64
| dpkg-checkbuilddeps: error: Unmet build dependencies: python-pip:amd64
python-setuptools:amd64 python-mako:amd64

"host architecture arm64", that is suspicious...


And then python - I'm still facing that issue with another package as well:

| Setting up python2.7-minimal:arm64 (2.7.13-2+deb9u2) ...
| /var/lib/dpkg/info/python2.7-minimal.postinst: 42:
/var/lib/dpkg/info/python2.7-minimal.postinst: python2.7: not found
| dpkg: error processing package python2.7-minimal:arm64 (--configure):
|  subprocess installed post-installation script returned error exit
status 127
| dpkg: dependency problems prevent configuration of python-minimal:arm64:
|  python-minimal:arm64 depends on python2.7-minimal (>= 2.7.13-1~);
however:
|   Package python2.7-minimal:arm64 is not configured yet.
|
| dpkg: error processing package python-minimal:arm64 (--configure):
|  dependency problems - leaving unconfigured
| Errors were encountered while processing:
|  python2.7-minimal:arm64
|  python-minimal:arm64
| E: Sub-process /usr/bin/dpkg returned an error code (1)

Corresponding build dependencies there:
Build-Depends: wget, cpio, unzip, rsync, python, bc

Here I get my job done by hacking it this way:
Build-Depends: wget, cpio, unzip, rsync, python:amd64, bc

Jan