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Message-ID: <ff12c314f3c122de9f2d9f5d826fac9e5e6248dc.camel@suse.de>
Subject: Re: [PATCH v14 07/11] arm64: kdump: introduce some macroes for
 crash kernel reservation
From:   Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To:     Chen Zhou <chenzhou10@huawei.com>, mingo@redhat.com,
        tglx@linutronix.de, rppt@kernel.org, dyoung@redhat.com,
        bhe@redhat.com, catalin.marinas@arm.com, will@kernel.org,
        corbet@lwn.net, John.P.donnelly@oracle.com, bhsharma@redhat.com,
        prabhakar.pkin@gmail.com
Cc:     horms@verge.net.au, robh+dt@kernel.org, arnd@arndb.de,
        james.morse@arm.com, xiexiuqi@huawei.com, guohanjun@huawei.com,
        huawei.libin@huawei.com, wangkefeng.wang@huawei.com,
        linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, kexec@lists.infradead.org
Date:   Thu, 04 Feb 2021 17:27:39 +0100
In-Reply-To: <a7951d7f651681fcfd45cea4f8b173c23cc34aa0.camel@suse.de>
References: <20210130071025.65258-1-chenzhou10@huawei.com>
         <20210130071025.65258-8-chenzhou10@huawei.com>
         <a7951d7f651681fcfd45cea4f8b173c23cc34aa0.camel@suse.de>
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On Thu, 2021-02-04 at 17:20 +0100, Nicolas Saenz Julienne wrote:
> Hi Chen,
>=20
> On Sat, 2021-01-30 at 15:10 +0800, Chen Zhou wrote:
> > Introduce macro CRASH_ALIGN for alignment, macro CRASH_ADDR_LOW_MAX
> > for upper bound of low crash memory, macro CRASH_ADDR_HIGH_MAX for
> > upper bound of high crash memory, use macroes instead.
> >=20
> > Besides, keep consistent with x86, use CRASH_ALIGN as the lower bound
> > of crash kernel reservation.
> >=20
> > Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> > Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> > ---
> > =C2=A0arch/arm64/include/asm/kexec.h | 6 ++++++
> > =C2=A0arch/arm64/mm/init.c           | 6 +++---
> > =C2=A02 files changed, 9 insertions(+), 3 deletions(-)
> >=20
> > diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/ke=
xec.h
> > index d24b527e8c00..3f6ecae0bc68 100644
> > --- a/arch/arm64/include/asm/kexec.h
> > +++ b/arch/arm64/include/asm/kexec.h
> > @@ -25,6 +25,12 @@
> > =C2=A0
> >=20
> > =C2=A0#define KEXEC_ARCH KEXEC_ARCH_AARCH64
> > =C2=A0
> >=20
> > +/* 2M alignment for crash kernel regions */
> > +#define CRASH_ALIGN	SZ_2M
> > +
> > +#define CRASH_ADDR_LOW_MAX	arm64_dma_phys_limit
>=20
> I wonder if you could use 'ARCH_LOW_ADDRESS_LIMIT', instead of creating a=
 new
> define.
>=20
> > +#define CRASH_ADDR_HIGH_MAX	MEMBLOCK_ALLOC_ACCESSIBLE
> > +
> > =C2=A0#ifndef __ASSEMBLY__
> > =C2=A0
> >=20
> > =C2=A0/**
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index 709d98fea90c..912f64f505f7 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -84,8 +84,8 @@ static void __init reserve_crashkernel(void)
> > =C2=A0
> >=20
> > =C2=A0	if (crash_base =3D=3D 0) {
> > =C2=A0		/* Current arm64 boot protocol requires 2MB alignment */
> > -		crash_base =3D memblock_find_in_range(0, arm64_dma_phys_limit,
> > -				crash_size, SZ_2M);
> > +		crash_base =3D memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MA=
X,
> > +				crash_size, CRASH_ALIGN);
>=20
> Actually we could get rid of CRASH_ADDR_LOW_MAX altogether if we used
> memblock_alloc_low() here (modulo the slight refactoring needed to accomm=
odate
> it).

Forget about these coments, I now see that you're deleting this whole funct=
ion
on the next patch and defaulting to a generic implementation. Sorry for the
noise.

Regards,
Nicolas


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