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From:   Zhangjin Wu <falcon@tinylab.org>
To:     w@1wt.eu
Cc:     arnd@arndb.de, falcon@tinylab.org, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, tanyuan@tinylab.org,
        thomas@t-8ch.de
Subject: Re: [PATCH v1 2/3] selftests/nolibc: fix up O= option support
Date:   Sat,  5 Aug 2023 02:40:23 +0800
Message-Id: <20230804184023.354950-1-falcon@tinylab.org>
In-Reply-To: <20230804175429.GC31163@1wt.eu>
References: <20230804175429.GC31163@1wt.eu>
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> On Fri, Aug 04, 2023 at 07:51:50PM +0200, Thomas Wei?schuh wrote:
> > On 2023-08-05 00:29:10+0800, Zhangjin Wu wrote:
[...]
> > > Do you mean here?
> > > 
> > >     # kernel image names by architecture
> > >     IMAGE_i386    = arch/x86/boot/bzImage
> > >     IMAGE_x86     = arch/x86/boot/bzImage
> > >     IMAGE_arm64   = arch/arm64/boot/Image
> > >     IMAGE_arm     = arch/arm/boot/zImage
> > >     IMAGE_mips    = vmlinuz
> > >     IMAGE_riscv   = arch/riscv/boot/Image
> > >     IMAGE         = $(IMAGE_$(ARCH))
> > >     IMAGE_NAME    = $(notdir $(IMAGE))
> > > 
> > > It does save another KERNEL_IMAGE macro in my future patch ;-)
> > > 
> > > But without O=, OUTPUT is also empty like objtree and when empty, it is
> > > assigned as $(CURDIR), not $(srctree) as we expected for IMAGE and .config. To
> > > be cleaner, objtree should also be used:
> > > 
> > >     - IMAGE         = $(IMAGE_$(ARCH))
> > >     + IMAGE         = $(objtree)/$(IMAGE_$(ARCH))
> > > 
> > > Is this what you want?
> > 
> > More like:
> > 
> > -	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(srctree)/$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
> > +	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(OUTPUT)$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
> > 
> > My assumption was that it's weird that we need to define such variables
> > ourselves.
> > 
> > Using an empty $(OUTPUT) would have been fine if make is run from the
> > root of the kernel tree. But that is not the case.
> > 
> > It still feels weird but I can't think of a nicer way, and it's not
> > a big issue. So let's keep that part the same.
> > 
> > Or maybe Willy has a better idea.
> 
> I've just glanced over the discussion, but I'm wondering, why not
> "$(objtree)/$(IMAGE)" instead ?
>

We used "$(objtree)/$(IMAGE)" originally, I thought of Thomas asked me to
further add "$(objtree)" in the first place of IMAGE,

     - IMAGE         = $(IMAGE_$(ARCH))
     + IMAGE         = $(objtree)/$(IMAGE_$(ARCH))

And then, we can use "IMAGE" directly in the qemu run & rerun targets:

    # run the tests after building the kernel
    run: kernel
    -	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(objtree)/$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(RUN_OUT)"
    +	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(RUN_OUT)"
    	$(Q)$(REPORT) "$(RUN_OUT)"
    
    # re-run the tests from an existing kernel
    rerun:
    -	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(objtree)/$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(RUN_OUT)"
    +	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(RUN_OUT)"
    	$(Q)$(REPORT) "$(RUN_OUT)"

Which one do you prefer? will renew this series soon.

And even further, I thought of puting everything to $(OUTPUT), but the
change is very ugly and not good for v6.6, If you like, I will send that
patch only as a discuss stuff.

Thanks,
Zhangjin

> Willy