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References: <20220529042318.2630379-1-masahiroy@kernel.org> <YpOLHkUZImdEr7yl@antec>
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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Mon, 30 May 2022 02:21:58 +0900
Message-ID: <CAK7LNATXjQdd2MGf2v_1WYP6zc0sMU31338Ca-2zKQttV9FYvg@mail.gmail.com>
Subject: Re: [PATCH] kbuild: ignore *.cmd files for objects that come from libgcc.a
To:     Stafford Horne <shorne@gmail.com>
Cc:     Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Guo Ren <guoren@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>,
        Sami Tolvanen <samitolvanen@google.com>,
        linux-csky@vger.kernel.org, Joel Stanley <joel@jms.id.au>,
        nicolas@debian.org
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On Mon, May 30, 2022 at 12:02 AM Stafford Horne <shorne@gmail.com> wrote:
>
> Cc Joel, Nicolas
>
> On Sun, May 29, 2022 at 01:23:18PM +0900, Masahiro Yamada wrote:
> > Guenter Roeck reported the build breakage for parisc and csky.
> > I confirmed nios2 and openrisc are broken as well.
>
> Joel reported and issue building the openrisc kernel as well with this error:
>
>     This fails at the link step:
>
>       LD      vmlinux.o
>     + or1k-elf-ld -r -o vmlinux.o --whole-archive
>     arch/openrisc/kernel/head.o init/built-in.a usr/built-in.a
>     arch/openrisc/built-in.a kernel/built-in.a certs/built-in.a
>     mm/built-in.a fs/built-in.a ipc/built-in.a security/built-in.a
>     crypto/built-in.a block/built-in.a lib/built-in.a drivers/built-in.a
>     sound/built-in.a net/built-in.a virt/built-in.a --no-whole-archive
>     --start-group lib/lib.a /usr/lib/gcc/or1k-elf/12/libgcc.a --end-group
>     or1k-elf-ld: /usr/lib/gcc/or1k-elf/12/libgcc.a: error adding symbols:
>     archive has no index; run ranlib to add one
>
> Is it the same? It might be good to have details of the error in the commit
> message.


Probably, no.

I do not know when the error above happens.


I got the following error message for  ARCH=openrisc allmodconfig.

  CHK     include/generated/compile.h
  UPD     include/generated/compile.h
  CC      init/version.o
  AR      init/built-in.a
  LD      vmlinux.o
  MODPOST vmlinux.symvers
.__mulsi3.o.cmd: No such file or directory
make[2]: *** [scripts/Makefile.modpost:59: vmlinux.symvers] Error 1
make[1]: *** [Makefile:1160: vmlinux] Error 2
make: *** [Makefile:350: __build_one_by_one] Error 2


>
> > The reason is that they borrow libgcc.a from the toolchains.
> >
> > For example, see this line in arch/parisc/Makefile:
> >
> >     LIBGCC          := $(shell $(CC) -print-libgcc-file-name)
> >
> > Some objects in libgcc.a are linked to vmlinux.o, but they do not have
> > .*.cmd files.
> >
> > Obviously, there is no EXPORT_SYMBOL in external objects. Ignore them.
> >
> > (Most of the architectures import library code into the kernel tree.
> > Perhaps those 4 architectures can do similar, but I am not sure.)
>
> Ill have a look at this.  Could you give an example of what you mean by import
> library code, from where?  OpenRISC imports builtins from libgcc, also we have
> string and other lib routines from within the port.
>
> -Stafford
>

"git grep __mulsi3" showed some *.S files of other architectures.

You can ask the authors of the following commits:

4e07dba7cb8c9c76a52d0e32b69f13bb583a9674
dbf4ed894c0fd85d421f7b3b9758ce95398d2925


-- 
Best Regards
Masahiro Yamada