[PATCH V9 20/20] riscv: compat: Add COMPAT Kbuild skeletal support

[Guo Ren]

On Thu, May 26, 2022 at 3:37 AM Heiko Stübner <heiko at sntech.de> wrote:
>
> Am Mittwoch, 25. Mai 2022, 18:08:22 CEST schrieb Guo Ren:
> > Thx Heiko & Guenter,
> >
> > On Wed, May 25, 2022 at 7:10 PM Heiko Stübner <heiko at sntech.de> wrote:
> > >
> > > Am Mittwoch, 25. Mai 2022, 12:57:30 CEST schrieb Heiko Stübner:
> > > > Am Mittwoch, 25. Mai 2022, 00:06:46 CEST schrieb Guenter Roeck:
> > > > > On Wed, May 25, 2022 at 01:46:38AM +0800, Guo Ren wrote:
> > > > > [ ... ]
> > > > >
> > > > > > > The problem is come from "__dls3's vdso decode part in musl's
> > > > > > > ldso/dynlink.c". The ehdr->e_phnum & ehdr->e_phentsize are wrong.
> > > > > > >
> > > > > > > I think the root cause is from musl's implementation with the wrong
> > > > > > > elf parser. I would fix that soon.
> > > > > > Not elf parser, it's "aux vector just past environ[]". I think I could
> > > > > > solve this, but anyone who could help dig in is welcome.
> > > > > >
> > > > >
> > > > > I am not sure I understand what you are saying here. Point is that my
> > > > > root file system, generated with musl a year or so ago, crashes with
> > > > > your patch set applied. That is a regression, even if there is a bug
> > > > > in musl.
> > Thx for the report, it's a valuable regression for riscv-compat.
> >
> > > >
> > > > Also as I said in the other part of the thread, the rootfs seems innocent,
> > > > as my completely-standard Debian riscv64 rootfs is also affected.
> > > >
> > > > The merged version seems to be v12 [0] - not sure how we this discussion
> > > > ended up in v9, but I just tested this revision in two variants:
> > > >
> > > > - v5.17 + this v9 -> works nicely
> > >
> > > I take that back ... now going back to that build I somehow also run into
> > > that issue here ... will investigate more.
> > Yeah, it's my fault. I've fixed up it, please have a try:
> >
> > https://lore.kernel.org/linux-riscv/20220525160404.2930984-1-guoren@kernel.org/T/#u
>
> very cool that you found the issue.
> I've tested your patch and it seems to fix the issue for me.
>
> Thanks for figuring out the cause
I should thx Guenter Roeck, It just surprised me that compat_vdso
could work with quite a lot of rv64 apps.

> Heiko
>
>
> > > > - v5.18-rc6 + this v9 (rebased onto it) -> breaks the boot
> > > >   The only rebase-conflict was with the introduction of restartable
> > > >   sequences and removal of the tracehook include, but turning CONFIG_RSEQ
> > > >   off doesn't seem to affect the breakage.
> > > >
> > > > So it looks like something changed between 5.17 and 5.18 that causes the issue.
> > > >
> > > >
> > > > Heiko
> > > >
> > > >
> > > > [0] https://lore.kernel.org/all/20220405071314.3225832-1-guoren@kernel.org/
> > > >
> > >
> > >
> > >
> > >
> >
> >
> >
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-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/