Re: [PATCH L-C v3 6/7] buildchroot-host: install qemu-static to support hybrid cross-compiles

[Cedric Hombourger <Cedric_Hombourger@mentor.com>]

On 11/8/19 8:22 AM, Jan Kiszka wrote:
> On 08.11.19 08:14, [ext] Jan Kiszka wrote:
>> On 08.11.19 08:07, Cedric Hombourger wrote:
>>> The Linux kernel has great support for cross-compiling the kernel image
>>> and modules. There is however no support/mechanism for 
>>> cross-compiling the
>>> build tools from its "scripts" directory. While HOSTCC may be set to 
>>> use
>>> our cross-compiler, the kernel build infrasture would then try to run
>>> foreign-arch binaries such as fixdep. The easiest and least 
>>> intrusive way
>>> to support this is to enable execution of such binaries via binfmt/qemu
>>> like we do in the buildchroot-target environment.
>>>
>>> Signed-off-by: Cedric Hombourger <Cedric_Hombourger@mentor.com>
>>> ---
>>>   meta/recipes-devtools/buildchroot/buildchroot-host.bb | 6 ++++++
>>>   1 file changed, 6 insertions(+)
>>>
>>> diff --git a/meta/recipes-devtools/buildchroot/buildchroot-host.bb 
>>> b/meta/recipes-devtools/buildchroot/buildchroot-host.bb
>>> index 408ad39..2e76acb 100644
>>> --- a/meta/recipes-devtools/buildchroot/buildchroot-host.bb
>>> +++ b/meta/recipes-devtools/buildchroot/buildchroot-host.bb
>>> @@ -15,3 +15,9 @@ BUILDCHROOT_PREINSTALL ?= " \
>>>       ${BUILDCHROOT_PREINSTALL_COMMON} \
>>>       libc6:${DISTRO_ARCH} \
>>>       crossbuild-essential-${DISTRO_ARCH}"
>>> +
>>> +buildchroot_install_files_append() {
>>> +    if [ -e '/usr/bin/qemu-${QEMU_ARCH}-static' ]; then
>>> +       sudo cp '/usr/bin/qemu-${QEMU_ARCH}-static' 
>>> '${BUILDCHROOT_DIR}/usr/bin/qemu-${QEMU_ARCH}-static'
>>> +    fi
>>> +}
>>>
>>
>> You didn't address my comment on this one. I doubt it's the right 
>> approach.
>>
>
> IOW: When we cross-compile linux-headers, the output is for the host 
> architecture only, not for the target. If the resulting package 
> suggest something different, that must be fixed.
see the response I just posted. I am afraid this is incorrect but again 
feel free to suggest otherwise with a bit more concrete meat and a look 
upstream...
>
> Jan
>