kbuild not creating output dirs

kbuild not creating output dirs

[Geoff Levand]

Hi Michal,

I was building Marc's kvm development kernel outside of the
sources (make O=), and I got the following build error:

  arch/arm64/kvm/../../../arch/arm/kvm/mmio.c: fatal error: opening dependency file arch/arm64/kvm/../../../arch/arm/kvm/.mmio.o.d: No such file or directory

The cause was that kbuild did not create the output directory
arch/arm64/kvm/../../../arch/arm/kvm, and so gcc failed.

Here is what was in his makefile:

  obj-$(CONFIG_KVM_ARM_HOST) += $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)

I changed this to build a composite and kbuild then created
the output directories:

  obj-$(CONFIG_KVM_ARM_HOST) += kvm.o
  kvm-$(CONFIG_KVM_ARM_HOST) += $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)

I guess kbuild used some other rules and saw the dependency on
the output directory.

So, my questions are:

Is it expected that the original rule should fail?
Is my fix the correct way?
Can I use some other way to get those output directories created?

Just FYI, the original source is here:

  https://git.kernel.org/cgit/linux/kernel/git/maz/arm-platforms.git/tree/arch/arm64/kvm/Makefile?h=kvm-arm64/kvm-for-next

Thanks for your help.

-Geoff

Re: kbuild not creating output dirs

[Christoffer Dall]

there was a similar problem with the kvm 32-bit makefile at some
point, the fix looks ok to me.

-Christoffer

On Wed, Apr 3, 2013 at 4:28 PM, Geoff Levand <geoff@infradead.org> wrote:
> Hi Michal,
>
> I was building Marc's kvm development kernel outside of the
> sources (make O=), and I got the following build error:
>
>   arch/arm64/kvm/../../../arch/arm/kvm/mmio.c: fatal error: opening dependency file arch/arm64/kvm/../../../arch/arm/kvm/.mmio.o.d: No such file or directory
>
> The cause was that kbuild did not create the output directory
> arch/arm64/kvm/../../../arch/arm/kvm, and so gcc failed.
>
> Here is what was in his makefile:
>
>   obj-$(CONFIG_KVM_ARM_HOST) += $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)
>
> I changed this to build a composite and kbuild then created
> the output directories:
>
>   obj-$(CONFIG_KVM_ARM_HOST) += kvm.o
>   kvm-$(CONFIG_KVM_ARM_HOST) += $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)
>
> I guess kbuild used some other rules and saw the dependency on
> the output directory.
>
> So, my questions are:
>
> Is it expected that the original rule should fail?
> Is my fix the correct way?
> Can I use some other way to get those output directories created?
>
> Just FYI, the original source is here:
>
>   https://git.kernel.org/cgit/linux/kernel/git/maz/arm-platforms.git/tree/arch/arm64/kvm/Makefile?h=kvm-arm64/kvm-for-next
>
> Thanks for your help.
>
> -Geoff
>
>
>
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> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm

Re: kbuild not creating output dirs

[Marc Zyngier]

On Wed, 3 Apr 2013 16:34:45 -0700, Christoffer Dall
<cdall@cs.columbia.edu>
wrote:
> there was a similar problem with the kvm 32-bit makefile at some
> point, the fix looks ok to me.
> 
> -Christoffer
> 
> On Wed, Apr 3, 2013 at 4:28 PM, Geoff Levand <geoff@infradead.org>
wrote:
>> Hi Michal,
>>
>> I was building Marc's kvm development kernel outside of the
>> sources (make O=), and I got the following build error:
>>
>>   arch/arm64/kvm/../../../arch/arm/kvm/mmio.c: fatal error: opening
>>   dependency file arch/arm64/kvm/../../../arch/arm/kvm/.mmio.o.d: No
such
>>   file or directory
>>
>> The cause was that kbuild did not create the output directory
>> arch/arm64/kvm/../../../arch/arm/kvm, and so gcc failed.
>>
>> Here is what was in his makefile:
>>
>>   obj-$(CONFIG_KVM_ARM_HOST) += $(addprefix ../../../virt/kvm/,
>>   kvm_main.o coalesced_mmio.o)
>>
>> I changed this to build a composite and kbuild then created
>> the output directories:
>>
>>   obj-$(CONFIG_KVM_ARM_HOST) += kvm.o
>>   kvm-$(CONFIG_KVM_ARM_HOST) += $(addprefix ../../../virt/kvm/,
>>   kvm_main.o coalesced_mmio.o)
>>
>> I guess kbuild used some other rules and saw the dependency on
>> the output directory.
>>
>> So, my questions are:
>>
>> Is it expected that the original rule should fail?
>> Is my fix the correct way?
>> Can I use some other way to get those output directories created?

Yeah, this looks like the thing to do. I'll fix the KVM/arm64 makefile.

Thanks for investigating.

        M.
-- 
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