Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <CAK7LNARuR5cturyngN31Oy=PwMG_-p5iOek2BuDSKHSyZg44Xg@mail.gmail.com>
 <mhng-7876bf10-0477-4ca6-af22-e3479e8ad123@palmer-ri-x1c9a>
In-Reply-To: <mhng-7876bf10-0477-4ca6-af22-e3479e8ad123@palmer-ri-x1c9a>
From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Fri, 21 Jul 2023 20:58:20 +0900
Message-ID: <CAK7LNASc9vXvHiDRarbKXq-m-9r0wso2VydBFMfd4sCt0mA_8w@mail.gmail.com>
Subject: Re: [PATCH -next] modpost: move some defines to the file head
To:     Palmer Dabbelt <palmer@rivosinc.com>
Cc:     wangkefeng.wang@huawei.com, mcgrof@kernel.org, nathan@kernel.org,
        ndesaulniers@google.com, nicolas@fjasle.eu,
        linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Thu, Jul 13, 2023 at 1:28=E2=80=AFAM Palmer Dabbelt <palmer@rivosinc.com=
> wrote:
>
> On Wed, 12 Jul 2023 08:55:23 PDT (-0700), masahiroy@kernel.org wrote:
> > +To: Luis Chamberlain, the commiter of the breakage
> >
> >
> >
> > On Wed, Jul 12, 2023 at 10:44=E2=80=AFAM Kefeng Wang <wangkefeng.wang@h=
uawei.com> wrote:
> >>
> >> with "module: Ignore RISC-V mapping symbols too", build error occurs,
> >>
> >> scripts/mod/modpost.c: In function =E2=80=98is_valid_name=E2=80=99:
> >> scripts/mod/modpost.c:1055:57: error: =E2=80=98EM_RISCV=E2=80=99 undec=
lared (first use in this function)
> >>   return !is_mapping_symbol(name, elf->hdr->e_machine =3D=3D EM_RISCV)=
;
> >>
> >> Fix it by moving the EM_RISCV to the file head, also some other
> >> defines in case of similar problem in the future.
> >
> >
> >
> > BTW, why is the flag 'is_riscv' needed?
> >
> >
> > All symbols starting with '$' look special to me.
> >
> >
> >
> > Why not like this?
> >
> >
> >        if (str[0] =3D=3D '$')
> >                  return true;
> >
> >        return false;
>
> There's a bit of commentary in the v1
> <https://lore.kernel.org/all/20230707054007.32591-1-palmer@rivosinc.com/>=
,
> but essentially it's not necessary.  I just wanted to play things safe
> and avoid changing the mapping symbol detection elsewhere in order to
> deal with RISC-V.
>
> IIRC we decided $ was special in RISC-V because there were some other
> ports that behaved that way, but it wasn't universal.  If folks are OK
> treating $-prefixed symbols as special everywhere that's fine with me, I
> just wasn't sure what the right answer was.
>
> There's also some similar arch-specific-ness with the labels and such in
> here.

Hi Palmer,

I am not a toolchain expert, but my gut feeling is
that the code was safer than needed.


I'd like to remove the 'is_riscv' switch rather than
applying this patch.

Will you send a patch, or do you want me to do so?


--
Best Regards
Masahiro Yamada