linux-kernel - Re: [PATCH v4 02/14] arm: add support for folded p4d page tables

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Date:   Mon, 11 May 2020 17:15:36 +0300
From:   Mike Rapoport <rppt@...ux.ibm.com>
To:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     Mike Rapoport <rppt@...nel.org>, Rich Felker <dalias@...c.org>,
        linux-ia64@...r.kernel.org,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        linux-sh@...r.kernel.org,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        linux-mm@...ck.org, Paul Mackerras <paulus@...ba.org>,
        linux-hexagon@...r.kernel.org, Will Deacon <will@...nel.org>,
        kvmarm@...ts.cs.columbia.edu, Jonas Bonn <jonas@...thpole.se>,
        linux-arch@...r.kernel.org, Brian Cain <bcain@...eaurora.org>,
        Marc Zyngier <maz@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Ley Foon Tan <ley.foon.tan@...el.com>,
        Catalin Marinas <catalin.marinas@....com>,
        uclinux-h8-devel@...ts.sourceforge.jp,
        Fenghua Yu <fenghua.yu@...el.com>,
        Arnd Bergmann <arnd@...db.de>, kvm-ppc@...r.kernel.org,
        Stefan Kristiansson <stefan.kristiansson@...nalahti.fi>,
        openrisc@...ts.librecores.org, Stafford Horne <shorne@...il.com>,
        Guan Xuetao <gxt@....edu.cn>,
        linux-arm-kernel@...ts.infradead.org,
        Christophe Leroy <christophe.leroy@....fr>,
        Tony Luck <tony.luck@...el.com>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        linux-kernel@...r.kernel.org,
        Michael Ellerman <mpe@...erman.id.au>,
        nios2-dev@...ts.rocketboards.org, linuxppc-dev@...ts.ozlabs.org,
        Łukasz Stelmach <l.stelmach@...sung.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Subject: Re: [PATCH v4 02/14] arm: add support for folded p4d page tables

Hi Marek,

On Mon, May 11, 2020 at 08:36:41AM +0200, Marek Szyprowski wrote:
> Hi Mike,
> 
> On 08.05.2020 19:42, Mike Rapoport wrote:
> > On Fri, May 08, 2020 at 08:53:27AM +0200, Marek Szyprowski wrote:
> >> On 07.05.2020 18:11, Mike Rapoport wrote:
> >>> On Thu, May 07, 2020 at 02:16:56PM +0200, Marek Szyprowski wrote:
> >>>> On 14.04.2020 17:34, Mike Rapoport wrote:
> >>>>> From: Mike Rapoport <rppt@...ux.ibm.com>
> >>>>>
> >>>>> Implement primitives necessary for the 4th level folding, add walks of p4d
> >>>>> level where appropriate, and remove __ARCH_USE_5LEVEL_HACK.
> >>>>>
> >>>>> Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
> > Can you please try the patch below:
> >
> > diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
> > index 963b5284d284..f86b3d17928e 100644
> > --- a/arch/arm/mm/init.c
> > +++ b/arch/arm/mm/init.c
> > @@ -571,7 +571,7 @@ static inline void section_update(unsigned long addr, pmdval_t mask,
> >   {
> >   	pmd_t *pmd;
> >   
> > -	pmd = pmd_off_k(addr);
> > +	pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, addr), addr), addr), addr);
> >   
> >   #ifdef CONFIG_ARM_LPAE
> >   	pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
> This fixes kexec issue! Thanks!
> 
> 
> Feel free to add:
> 
> Reported-by: Marek Szyprowski <m.szyprowski@...sung.com>
> Fixes: 218f1c390557 ("arm: add support for folded p4d page tables")
> Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>

Thanks for testing!

The patch is still in mmotm tree, so I don't think "Fixes" apply.

Andrew, would you like me to send the fix as a formal patch or will pick
it up as a fixup?

> Best regards
> -- 
> Marek Szyprowski, PhD
> Samsung R&D Institute Poland
> 

-- 
Sincerely yours,
Mike.