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

[Alexander Smirnov <asmirnov@ilbers.de>]

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 :-(

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.

Alex

> 
>>
>> To enable cross-compilation, the variable ISAR_CROSS_COMPILE should be set
>> to "1" in local.conf file.
> 
> I will retry that series soon, on my standard testcase jailhouse-images.
> It's growing and urgently needs an accelerator :).
> 
> Jan
>