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From:   Evan Green <evan@rivosinc.com>
Date:   Mon, 1 May 2023 08:26:19 -0700
Message-ID: <CALs-HsuP1moOdZQG_Ur3J3cQ1J+j9Zr-tiSgAkvmCsOXaca9ag@mail.gmail.com>
Subject: Re: [PATCH v2] RISC-V: fix sifive and thead section mismatches in errata
To:     Conor Dooley <conor@kernel.org>
Cc:     Randy Dunlap <rdunlap@infradead.org>, linux-kernel@vger.kernel.org,
        Heiko Stuebner <heiko@sntech.de>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        linux-riscv@lists.infradead.org
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On Sat, Apr 29, 2023 at 12:11=E2=80=AFPM Conor Dooley <conor@kernel.org> wr=
ote:
>
> On Sat, Apr 29, 2023 at 12:06:19PM -0700, Evan Green wrote:
> > On Sat, Apr 29, 2023 at 10:58=E2=80=AFAM Randy Dunlap <rdunlap@infradea=
d.org> wrote:
> > >
> > >
> > >
> > > On 4/29/23 10:48, Evan Green wrote:
> > > > On Sat, Apr 29, 2023 at 10:24=E2=80=AFAM Conor Dooley <conor@kernel=
.org> wrote:
> > > >>
> > > >> On Sat, Apr 29, 2023 at 10:21:39AM -0700, Evan Green wrote:
> > > >>> On Sat, Apr 29, 2023 at 8:52=E2=80=AFAM Randy Dunlap <rdunlap@inf=
radead.org> wrote:
> > > >>>>
> > > >>>> When CONFIG_MODULES is set, __init_or_module becomes <empty>, bu=
t when
> > > >>>> CONFIG_MODULES is not set, __init_or_module becomes __init.
> > > >>>> In the latter case, it causes section mismatch warnings:
> > > >>>>
> > > >>>> WARNING: modpost: vmlinux.o: section mismatch in reference: risc=
v_fill_cpu_mfr_info (section: .text) -> sifive_errata_patch_func (section: =
.init.text)
> > > >>>> WARNING: modpost: vmlinux.o: section mismatch in reference: risc=
v_fill_cpu_mfr_info (section: .text) -> thead_errata_patch_func (section: .=
init.text)
> > > >>>>
> > > >>>> Fixes: bb3f89487fd9 ("RISC-V: hwprobe: Remove __init on probe_ve=
ndor_features()")
> > > >>>> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> > > >>>> Cc: Heiko Stuebner <heiko@sntech.de>
> > > >>>> Cc: Paul Walmsley <paul.walmsley@sifive.com>
> > > >>>> Cc: Palmer Dabbelt <palmer@dabbelt.com>
> > > >>>> Cc: Albert Ou <aou@eecs.berkeley.edu>
> > > >>>> Cc: linux-riscv@lists.infradead.org
> > > >>>> Cc: Conor Dooley <conor@kernel.org>
> > > >>>> Cc: Evan Green <evan@rivosinc.com>
> > > >>>> ---
> > > >>>
> > > >>> Thanks, Randy. I'm confused at how I didn't see that when I made =
the
> > > >>> original fix. I feel like repro of these section mismatch errors
> > > >>> depend on some other factor I'm not understanding. In any case:
> > > >>
> > > >> Perhaps you had a cut-down config that did not enable either of th=
e
> > > >> relevant ARCH_ options to get those errata compiled?
> > > >
> > > > It was weird, my original "fix" (the one listed in this Fixes tag) =
was
> > > > needed because while the hwprobe series was clean on Palmer's branc=
h,
> > > > it generated a "section mismatch" on linux-next. As noted here, it =
was
> > > > only with !CONFIG_MODULES, so I explicitly remember generating that
> > > > config and checking it on linux-next to generate this "fix", and it
> > > > came out clean. It's like the robots are getting smarter.
> > > > -Evan
> > >
> > > I observed the problem in 8 out of 20 randconfig builds,
> > > using linux-next 20230427.
> >
> > Oh interesting, so not the stock k210_nommu defconfig. That makes me
> > feel a little better at least.
>
> Ohh man, that's a pretty bad config to try use (if that's your default)
> for build testing stuff. The k210_mmu defconfig doesn't enable anything
> other than SOC_CANAAN.
> I could reproduce Randy's issue on defconfig w/ CONFIG_MODULES disabled.

That's the one that caught me before, so I remembered it as being
"different". I'll try what you describe above next time I'm hunting
for section mismatches.
-Evan