Re: linux-parisc compile failure in current git

[Helge Deller <deller@gmx.de>]

On 8/19/22 14:45, Masahiro Yamada wrote:
> On Thu, Aug 18, 2022 at 5:59 AM Randy Dunlap <rdunlap@infradead.org> wrote:
>>
>> Hi--
>>
>> On 6/23/21 13:33, Helge Deller wrote:
>>> * Masahiro Yamada <masahiroy@kernel.org>:
>>>> On Thu, Jun 10, 2021 at 4:04 PM Helge Deller <deller@gmx.de> wrote:
>>>>>
>>>>> Hi Masahiro,
>>>>>
>>>>> On 6/10/21 4:03 AM, Masahiro Yamada wrote:
>>>>>> On Thu, Jun 10, 2021 at 7:50 AM Helge Deller <deller@gmx.de> wrote:
>>
>> [snip]
>>
>>>>>> But, please keep in mind that there is an issue remaining.
>>>>>>
>>>>>> Please see this code:
>>>>>>
>>>>>> ifdef CONFIG_64BIT
>>>>>> UTS_MACHINE := parisc64
>>>>>> CHECKFLAGS += -D__LP64__=1
>>>>>> CC_ARCHES = hppa64
>>>>>> LD_BFD := elf64-hppa-linux
>>>>>> else # 32-bit
>>>>>> CC_ARCHES = hppa hppa2.0 hppa1.1
>>>>>> LD_BFD := elf32-hppa-linux
>>>>>> endif
>>>>>>
>>>>>>
>>>>>> UTS_MACHINE is determined by CONFIG_64BIT.
>>>>>>
>>>>>> CONFIG_64BIT is defined only after Kconfig is finished.
>>>>>> When you are trying to configure the .config,
>>>>>> CONFIG_64BIT is not defined yet.
>>>>>> So UTS_MACHINE is always 'parisc'.
>>>>>
>>>>> Yes.
>>>>> See above, but it worked when I had SUBARCH=x86 (when running my laptop).
>>>>>
>>>>>
>>>>>> As you know, Kconfig files now have a bunch of 'cc-option' syntax
>>>>>> to check the compiler capability in Kconfig time.
>>>>>> Hence, you need to provide a proper compiler in Kconfig time too.
>>>>>>
>>>>>> When you build a 64-bit parisc kernel on a 32-bit parisc machine,
>>>>>
>>>>> Please note, that we don't have a 64-bit parisc userspace yet (just kernel).
>>>>> This means, that all builds on parisc machines are 32bit and do a
>>>>> cross-compilation to a parisc64 kernel if requested in the .config.
>>>>>
>>>>>> Kconfig is passed with CC=gcc since SUBARCH==UTS_MACHINE==parisc.
>>>>>> After Kconfig, CROSS_COMPILE=hppa64-* is set,
>>>>>> and the kernel is built by CC=hppa64-*-gcc.
>>>>>
>>>>> Right. That is the old behaviour. Based on the CONFIG_64BIT option
>>>>> the hppa64 compiler is choosen for CROSS_COMPILE.
>>>>>
>>>>>> So, Kconfig evaluated a compiletely different compiler. This is pointless.
>>>>>
>>>>> Yes, probably.
>>>>>
>>>>>
>>>>>> There are some options
>>>>>>
>>>>>> [option 1]
>>>>>>    revert the parisc bit of 23243c1ace9fb4eae2f75e0fe0ece8e3219fb4f3
>>>>>>    This will restore the functionality you may want, but
>>>>>>    as I said above, Kconfig is doing pointless things.
>>>>>
>>>>> as mentioned above: Doesn't solve the issue.
>>>>>
>>>>>> [option 2]
>>>>>>     Stop using cc-cross-prefix, and pass CROSS_COMPILE explicitly.
>>>>>>     This is what many architectures including arm, arm64 do.
>>>>>>     You need to explicitly pass CROSS_COMPILE=aarch64-linux-gnu- etc.
>>>>>>     if you are cross-compiling arm64.
>>>>>
>>>>> Might be an option, but it's not as handy as simply choosing CONFIG_64BIT
>>>>> and then things are done automatically.
>>>>>
>>>>>> [option 3]
>>>>>>     Introduce ARCH=parisc64.
>>>>>>
>>>>>>     When you are building 64-bit kernel, you can pass ARCH=parisc64
>>>>>>      A patch attached.  (but not tested much)
>>>>>
>>>>> Tried it, but doesn't work.
>>>>> asm-offsets.c is still preprocessed with 32bit compiler (gcc, not hppa20-gcc).
>>>>>
>>>>> Thanks for your help so far!
>>>>> If you like I'm happy to give you an account on a hppa64 machine to reproduce yourself.
>>>>> I'll now try to bisect where it goes wrong. There must be something else before commit 23243c1ace9fb4eae2f75e0fe0ece8e3219fb4f3.
>>>>>
>>>>> Helge
>>>>
>>>>
>>>> Sorry for my late reply.
>>>
>>> Me too.... :-(
>>
>> Sorry to jump in even later, but:
>>
>> I see that
>> $ make ARCH=parisc64 defconfig
>> does set CONFIG_64BIT.
>
> Strange. It does for me.
> masahiro@grover:~/ref/linux-next$ make ARCH=parisc64 defconfig
> *** Default configuration is based on 'generic-64bit_defconfig'
> #
> # configuration written to .config
> #
> masahiro@grover:~/ref/linux-next$ grep CONFIG_64BIT .config
> CONFIG_64BIT=y

Yes, as Randy said, this works.

>> Is there a way to do
>> $ make ARCH=parisc64 allmodconfig
>> ?
>> That does not set CONFIG_64BIT in my testing.
>> (testing on linux-next-20220817)
>
> Right.
> allmodconfig does not set CONFIG_64BIT.
>
> I think it is the same as before.

Yep.

> Is this thread related?

What thread?

> The reason is 64BIT depends on PA8X00.
>
> allmodconfig chooses PA7000 instead of PA8X00
> in the "Processor type" choice since
> PA7000 is the default.
>
>
> If you apply this patch,
>
>
>
> diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
> index 7f059cd1196a..458b8e22e240 100644
> --- a/arch/parisc/Kconfig
> +++ b/arch/parisc/Kconfig
> @@ -146,7 +146,7 @@ menu "Processor type and features"
>
>  choice
>         prompt "Processor type"
> -       default PA7000
> +       default PA8X00
>
>  config PA7000
>         bool "PA7000/PA7100"
>
> allmodconfig will start enabling CONFIG_64BIT,
> but it is up to Helge.

That patch "partly" works, in the sense that with:
make ARCH=parisc64 randconfig

you randomly end up with a 32- or 64-bit kernel.
Since "ARCH=parisc64" was given, one probably would expect a 64-bit-enabled kernel randconfig,
and with "ARCH=parisc" a 32-bit randconfig.
But, I'm not sure if this intended or not and works that way on other arches as well.

As written in the other mail, I added this patch in for-next:
https://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux.git/commit/?h=for-next&id=34793a5d09d9122f90acfa7e8f705436d5090d4d
The downside is, you need to give a special make target: parisc_randconfig / parisc64_randconfig

Helge