Re: [PATCH v2] arm: Add Kconfig entry to select CONFIG_DTB_FILE

[Jan Beulich <jbeulich@xxxxxxxx>]

On 09.03.2021 14:55, Michal Orzel wrote:
> 
> 
> On 09.03.2021 14:32, Julien Grall wrote:
>>
>>
>> On 09/03/2021 11:07, Jan Beulich wrote:
>>> On 09.03.2021 11:20, Julien Grall wrote:
>>>> On 09/03/2021 07:34, Michal Orzel wrote:
>>>>> On 08.03.2021 15:31, Julien Grall wrote:
>>>>>> On 08/03/2021 13:59, Michal Orzel wrote:
>>>>>>> --- a/xen/arch/arm/Makefile
>>>>>>> +++ b/xen/arch/arm/Makefile
>>>>>>> @@ -68,7 +68,7 @@ extra-y += $(TARGET_SUBARCH)/head.o
>>>>>>>       #obj-bin-y += ....o
>>>>>>>     -ifdef CONFIG_DTB_FILE
>>>>>>> +ifneq ($(CONFIG_DTB_FILE),"")
>>>>>>>     obj-y += dtb.o
>>>>>>>     AFLAGS-y += -DCONFIG_DTB_FILE=\"$(CONFIG_DTB_FILE)\"
>>>>>>>     endif
>>>>>>> @@ -137,8 +137,6 @@ asm-offsets.s: $(TARGET_SUBARCH)/asm-offsets.c
>>>>>>>     xen.lds: xen.lds.S
>>>>>>>         $(CPP) -P $(a_flags) -MQ $@ -o $@ $<
>>>>>>>     -dtb.o: $(CONFIG_DTB_FILE)
>>>>>>> -
>>>>>>
>>>>>> Why is this dropped?
>>>>> 1)This line is not needed as it has no impact on creating dtb.o
>>>>> 2)It causes the build failure once CONFIG_DTB_FILE option is in the 
>>>>> Kconfig as string within quotes.
>>>>
>>>> Because of 1), this should have ideally be part of a separate patch. But
>>>> I am OK to keep it in this patch so long it is explained in the commit
>>>> message.
>>>
>>> Wasn't the intention to have dtb.o re-compiled when the blob
>>> has changed? This would be lost with the removal of this line.
>>
>> Ah yes. I was only thinking about a name change (this would be caught via 
>> the update of the config header) and not a file update.
>>
> I already pushed v3 but I agree. Something like this would do the job:
> dtb.o: $(subst $\",,$(CONFIG_DTB_FILE))
> to remove quotes

Besides struggling with the $\", may I suggest
$(patsubst "%",%,$(CONFIG_DTB_FILE))? If the double quote needs
special treatment, I think it wants to be done via an abstraction
similar to squote (near the top of ./Config.mk).

Jan