linux-kernel - Re: [PATCH] parisc: suppress error messages for 'make clean'

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Date:   Sun, 10 May 2020 22:28:24 +0200
From:   Helge Deller <deller@....de>
To:     Masahiro Yamada <masahiroy@...nel.org>
Cc:     "James E . J . Bottomley" <James.Bottomley@...senpartnership.com>,
        linux-parisc@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] parisc: suppress error messages for 'make clean'

On 10.05.20 03:19, Masahiro Yamada wrote:
> Hi Helge,
>
> On Sun, May 10, 2020 at 2:39 AM Helge Deller <deller@....de> wrote:
>>
>> * Masahiro Yamada <masahiroy@...nel.org>:
>>> Hi Helge,
>>>
>>> On Sat, May 9, 2020 at 6:46 AM Helge Deller <deller@....de> wrote:
>>>>
>>>> * Masahiro Yamada <masahiroy@...nel.org>:
>>>>> On Sat, Apr 25, 2020 at 2:47 PM Masahiro Yamada <masahiroy@...nel.org> wrote:
>>>>>>
>>>>>> 'make ARCH=parisc clean' emits a tons of error messages as follows:
>>>>>>
>>>>>>   $ make ARCH=parisc clean
>>>>>>   gcc: error: unrecognized command line option '-mno-space-regs'
>>>>>>   gcc: error: unrecognized command line option '-mfast-indirect-calls'; did you mean '-mforce-indirect-call'?
>>>>>>   gcc: error: unrecognized command line option '-mdisable-fpregs'
>>>>>>   gcc: error: missing argument to '-Wframe-larger-than='
>>>>>>   gcc: error: unrecognized command line option '-mno-space-regs'
>>>>>>   gcc: error: unrecognized command line option '-mfast-indirect-calls'; did you mean '-mforce-indirect-call'?
>>>>>>   gcc: error: unrecognized command line option '-mdisable-fpregs'
>>>>>>   gcc: error: missing argument to '-Wframe-larger-than='
>>>>>>     ...
>>>>>>
>>>>>> You can supporess them except '-Wframe-larger-than' by setting correct
>>>>>> CROSS_COMPILE=, but we should not require any compiler for cleaning.
>>>>>>
>>>>>> This $(shell ...) is evaluated so many times because LIBGCC is exported.
>>>>>> Use the ':=' operator to evaluate it just once, and sink the stderr.
>>>>>>
>>>>>
>>>>> Applied to linux-kbuild.
>>>>
>>>> That patch breaks then building the boot loader/compressor:
>>>> ...
>>>>   hppa-linux-gnu-ld    -X -e startup --as-needed -T arch/parisc/boot/compressed/vmlinux.lds arch/parisc/boot/compressed/head.o arch/parisc/boot/compressed/real2.o arch/parisc/boot/compressed/firmware.o arch/parisc/boot/compressed/misc.o arch/parisc/boot/compressed/piggy.o -o arch/parisc/boot/compressed/vmlinux
>>>> hppa-linux-gnu-ld: arch/parisc/boot/compressed/misc.o: in function `dec_vli':
>>>> (.text+0x104): undefined reference to `__ashldi3'
>>>> hppa-linux-gnu-ld: arch/parisc/boot/compressed/misc.o: in function `lzma_len':
>>>> (.text+0x2b0): undefined reference to `$$mulI'
>>>> hppa-linux-gnu-ld: (.text+0x344): undefined reference to `$$mulI'
>>>> hppa-linux-gnu-ld: (.text+0x3f8): undefined reference to `$$mulI'
>>>>
>>>>
>>>> The patch below works, but I wonder if it's possible to avoid
>>>> to examine LIBGCC twice....?
>>>>
>>>> Helge
>>>
>>>
>>> Sorry for the breakage.
>>>
>>> How about moving LIBGCC below ?
>>
>> Good idea.
>> The patch below does work for me.
>> We do not need $KBUILD_CFLAGS to get the libgcc.a filename,
>
>
> I not not sure about this change.
> Generally speaking, the path to libgcc.a is affected
> by compiler flags, especially, bit size flags,
> endian flags, etc.
>
> For example, my distro gcc is biarch for i386/x86_64.
>
> $ gcc -print-libgcc-file-name
> /usr/lib/gcc/x86_64-linux-gnu/9/libgcc.a
> $ gcc -m64 -print-libgcc-file-name
> /usr/lib/gcc/x86_64-linux-gnu/9/libgcc.a
> $ gcc -m32 -print-libgcc-file-name
> /usr/lib/gcc/x86_64-linux-gnu/9/32/libgcc.a
>
> One real example in Linux is arch/arc/Makefile.
> ARC supports both big endian and little endian.
>
> If you drop cflags-y from line 59
> of arch/arc/Makefile, vmlinux fails to link
> due to endian mismatch.
>
>
> I am not familiar with parisc.
> Also, as it turned out,
> this change is not so trivial.
>
> I think the best approach is to leave this up to you
> since you are the parisc maintainer.

Yes, I knew about the possible biarch options.
On parisc that's not relevant yet.


> I will drop this patch from my kbuild tree,
> then you will apply what you think is best
> to your tree.
>
> What do you think?

Sure, I'll take it through the parisc tree.

Thanks!
Helge



>> so we do not need to pipe the output to /dev/null either.
>> Can you try if that works, and if yes, can you apply it?
>>
>> Helge
>>
>>
>> diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile
>> index 628cd8bb7ad8..fadbbd010337 100644
>> --- a/arch/parisc/Makefile
>> +++ b/arch/parisc/Makefile
>> @@ -21,8 +21,6 @@ KBUILD_IMAGE := vmlinuz
>>
>>  NM             = sh $(srctree)/arch/parisc/nm
>>  CHECKFLAGS     += -D__hppa__=1
>> -LIBGCC         = $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
>> -export LIBGCC
>>
>>  ifdef CONFIG_64BIT
>>  UTS_MACHINE    := parisc64
>> @@ -110,6 +108,8 @@ cflags-$(CONFIG_PA8X00)             += -march=2.0 -mschedule=8000
>>  head-y                 := arch/parisc/kernel/head.o
>>
>>  KBUILD_CFLAGS  += $(cflags-y)
>> +LIBGCC         := $(shell $(CC) -print-libgcc-file-name)
>> +export LIBGCC
>>
>>  kernel-y                       := mm/ kernel/ math-emu/
>>
>
>