[PATCH] riscv: Fix 32-bit RISC-V boot failure

[Bin Meng]

On Thu, Jul 22, 2021 at 1:53 PM Palmer Dabbelt <palmerdabbelt at google.com> wrote:
>
> On Thu, 15 Jul 2021 19:14:20 PDT (-0700), bmeng.cn at gmail.com wrote:
> > On Thu, Jul 8, 2021 at 9:29 PM Bin Meng <bmeng.cn at gmail.com> wrote:
> >>
> >> Hi Palmer,
> >>
> >> On Thu, Jul 1, 2021 at 10:20 AM Bin Meng <bmeng.cn at gmail.com> wrote:
> >> >
> >> > On Thu, Jul 1, 2021 at 10:08 AM Kefeng Wang <wangkefeng.wang at huawei.com> wrote:
> >> > >
> >> > >
> >> > > On 2021/6/30 19:58, Bin Meng wrote:
> >> > > > On Mon, Jun 28, 2021 at 11:21 AM Bin Meng <bmeng.cn at gmail.com> wrote:
> >> > > >> On Mon, Jun 28, 2021 at 10:28 AM Kefeng Wang <wangkefeng.wang at huawei.com> wrote:
> >> > > >>>
> >> > > >>> On 2021/6/28 9:15, Bin Meng wrote:
> >> > > >>>> On Mon, Jun 28, 2021 at 8:53 AM Kefeng Wang <wangkefeng.wang at huawei.com> wrote:
> >> > > >>>>> Hi， sorry for the mistake，the bug is fixed by
> >> > > >>>>>
> >> > > >>>>> https://lore.kernel.org/linux-riscv/20210602085517.127481-2-wangkefeng.wang@huawei.com/
> >> > > >>>> What are we on the patch you mentioned?
> >> > > >>>>
> >> > > >>>> I don't see it applied in the linux/master.
> >> > > >>>>
> >> > > >>>> Also there should be a "Fixes" tag and stable at vger.kernel.org cc'ed
> >> > > >>>> because 32-bit is broken since v5.12.
> >> > > >>> https://kernel.googlesource.com/pub/scm/linux/kernel/git/riscv/linux/+/c9811e379b211c67ba29fb09d6f644dd44cfcff2
> >> > > >>>
> >> > > >>> it's on Palmer' riscv-next.
> >> > > >> Not sure riscv-next is for which release? This is a regression and
> >> > > >> should be on 5.13.
> >> > > >>
> >> > > >>> Hi Palmer, should I resend or could you help me to add the fixes tag?
> >> > > > Your patch mixed 2 things (fix plus one feature) together, so it is
> >> > > > not proper to back port your patch.
> >> > >
> >> > > "mem=" will change the range of memblock, so the fix part must be included.
> >> > >
> >> >
> >> > Yes, so you can rebase the "mem=" changes on top of my patch.
> >> >
> >> > The practice is that we should not mix 2 things in one patch. I can
> >> > imagine that you wanted to add "mem=" to RISC-V and suddenly found the
> >> > existing logic was broken, so you sent one patch to do both.
> >> >
> >> > >
> >> > > >
> >> > > > Here is my 2 cents:
> >> > > >
> >> > > > 1. Drop your patch from riscv-next
> >> > > > 2. Apply my patch as it is a simple fix to previous commit. This
> >> > > > allows stable kernel to cherry-pick the fix to v5.12 and v5.13.
> >> > > > 3. Rebase your patch against mine, and resend v2
> >> > > >
> >> > > > Let me know if this makes sense.
> >> > >
> >> > > It is not a big problem for me, but I have no right abourt riscv-next,
> >> > >
> >> > > let's wait Palmer's advise.
> >> > >
> >> >
> >> > Sure. Palmer, let me know your thoughts.
> >>
> >> Ping?
> >
> > Ping?
>
> Sorry, I missed this one.  It looks like the patch that adds mem= and
> fixes the bug has already been merged, so I'm not really quite sure what
> the right thing to do is here: we don't really want the mem= code on
> stable, but we do want the fix.  I went ahead and did
>
> commit 444818b599189fd8b6c814da542ff8cfc9fe67d4 (HEAD -> fixes, palmer/fixes)
> gpg: Signature made Wed 21 Jul 2021 10:21:05 PM PDT
> gpg:                using RSA key 2B3C3747446843B24A943A7A2E1319F35FBB1889
> gpg:                issuer "palmer at dabbelt.com"
> gpg: Good signature from "Palmer Dabbelt <palmer at dabbelt.com>" [ultimate]
> gpg:                 aka "Palmer Dabbelt <palmerdabbelt at google.com>" [ultimate]
> Merge: e73f0f0ee754 d0e4dae74470
> Author: Palmer Dabbelt <palmerdabbelt at google.com>
> Date:   Wed Jul 21 22:18:58 2021 -0700
>
>     Merge remote-tracking branch 'riscv/riscv-fix-32bit' into fixes
>
>     This contains a single fix for 32-bit boot.  It happens this was already
>     fixed by c9811e379b21 ("riscv: Add mem kernel parameter support"), but
>     the bug existed before that feature addition so I've applied the patch
>     earlier and then merged it in (which results in a conflict, which is
>     fixed via not changing the resulting tree).
>
>     * riscv/riscv-fix-32bit:
>       riscv: Fix 32-bit RISC-V boot failure
>
> as that"s the best I could come up with -- then the fix will land on
> master, which should cause it to get pulled onto stable.
>
> Greg: is there a better way to make something like this get to stable?

We can:

1. git revert c9811e379b21 ("riscv: Add mem kernel parameter support")
2. git am <this patch>, cc stable
3. Kefeng resent a new patch that adds the mem kernel parameter
support, on top of mine

Regards,
Bin