From: Will Deacon <will@kernel.org>
To: Bhupesh Sharma <bhsharma@redhat.com>
Cc: John Donnelly <john.p.donnelly@oracle.com>,
chenzhou <chenzhou10@huawei.com>,
Simon Horman <horms@verge.net.au>,
Devicetree List <devicetree@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Baoquan He <bhe@redhat.com>,
Linux Doc Mailing List <linux-doc@vger.kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
guohanjun@huawei.com,
kexec mailing list <kexec@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Rob Herring <robh+dt@kernel.org>,
James Morse <james.morse@arm.com>,
nsaenzjulienne@suse.de,
Prabhakar Kushwaha <prabhakar.pkin@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Prabhakar Kushwaha <pkushwaha@marvell.com>,
RuiRui Yang <dyoung@redhat.com>, Ingo Molnar <mingo@redhat.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v8 0/5] support reserving crashkernel above 4G on arm64 kdump
Date: Thu, 4 Jun 2020 08:14:11 +0100 [thread overview]
Message-ID: <20200604071410.GA30155@willie-the-truck> (raw)
In-Reply-To: <CACi5LpN-+NRnaDoWWWidbzma8BNzmofA5FQBV=cPF1Mc84FpFg@mail.gmail.com>
On Thu, Jun 04, 2020 at 01:17:06AM +0530, Bhupesh Sharma wrote:
> On Wed, Jun 3, 2020 at 9:03 PM John Donnelly <john.p.donnelly@oracle.com> wrote:
> > > On Jun 3, 2020, at 8:20 AM, chenzhou <chenzhou10@huawei.com> wrote:
> > > On 2020/6/3 19:47, Prabhakar Kushwaha wrote:
> > >>>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> > >>>> index 7f9e5a6dc48c..bd67b90d35bd 100644
> > >>>> --- a/kernel/crash_core.c
> > >>>> +++ b/kernel/crash_core.c
> > >>>> @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
> > >>>> return 0;
> > >>>> }
> > >>>>
> > >>>> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
> > >>>> + low_base = memblock_find_in_range(0,0xc0000000, low_size, CRASH_ALIGN);
> > >>>> if (!low_base) {
> > >>>> pr_err("Cannot reserve %ldMB crashkernel low memory,
> > >>>> please try smaller size.\n",
> > >>>> (unsigned long)(low_size >> 20));
> > >>>>
> > >>>>
> > >>> I suspect 0xc0000000 would need to be a CONFIG item and not hard-coded.
> > >>>
> > >> if you consider this as valid change, can you please incorporate as
> > >> part of your patch-set.
> > >
> > > After commit 1a8e1cef7 ("arm64: use both ZONE_DMA and
> > > ZONE_DMA32"),the 0-4G memory is splited to DMA [mem
> > > 0x0000000000000000-0x000000003fffffff] and DMA32 [mem
> > > 0x0000000040000000-0x00000000ffffffff] on arm64.
> > >
> > > From the above discussion, on your platform, the low crashkernel fall
> > > in DMA32 region, but your environment needs to access DMA region, so
> > > there is the call trace.
> > >
> > > I have a question, why do you choose 0xc0000000 here?
> > >
> > > Besides, this is common code, we also need to consider about x86.
> > >
> >
> > + nsaenzjulienne@suse.de
> >
> > Exactly . This is why it needs to be a CONFIG option for Raspberry
> > .., or device tree option.
> >
> >
> > We could revert 1a8e1cef7 since it broke Arm kdump too.
>
> Well, unfortunately the patch for commit 1a8e1cef7603 ("arm64: use
> both ZONE_DMA and ZONE_DMA32") was not Cc'ed to the kexec mailing
> list, thus we couldn't get many eyes on it for a thorough review from
> kexec/kdump p-o-v.
>
> Also we historically never had distinction in common arch code on the
> basis of the intended end use-case: embedded, server or automotive, so
> I am not sure introducing a Raspberry specific CONFIG option would be
> a good idea.
Right, we need a fix that works for everybody, since we try hard for a
single Image that works for all platforms.
What I don't really understand is why, with Chen's patches applied, we can't
just keep the crashkernel out of the DMA zones altogether when no base is
specified. I guess I'll just look out for your patch!
Will
next prev parent reply other threads:[~2020-06-04 7:14 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-21 9:38 [PATCH v8 0/5] support reserving crashkernel above 4G on arm64 kdump Chen Zhou
2020-05-21 9:38 ` [PATCH v8 1/5] x86: kdump: move reserve_crashkernel_low() into crash_core.c Chen Zhou
2020-05-26 0:56 ` Baoquan He
2020-05-21 9:38 ` [PATCH v8 2/5] arm64: kdump: reserve crashkenel above 4G for crash dump kernel Chen Zhou
2020-05-26 0:59 ` Baoquan He
2020-05-21 9:38 ` [PATCH v8 3/5] arm64: kdump: add memory for devices by DT property, low-memory-range Chen Zhou
2020-05-21 9:38 ` [PATCH v8 4/5] kdump: update Documentation about crashkernel on arm64 Chen Zhou
2020-05-21 9:38 ` [PATCH v8 5/5] dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump Chen Zhou
2020-05-21 13:29 ` Rob Herring
2020-05-22 3:24 ` chenzhou
2020-05-26 21:18 ` Rob Herring
2020-05-29 16:11 ` James Morse
2020-06-20 3:54 ` chenzhou
2020-05-26 1:42 ` [PATCH v8 0/5] support reserving crashkernel above 4G on " Baoquan He
2020-05-26 2:28 ` chenzhou
2020-05-28 22:20 ` John Donnelly
2020-05-29 8:05 ` Will Deacon
2020-06-01 12:02 ` Prabhakar Kushwaha
2020-06-01 19:30 ` John Donnelly
2020-06-01 21:02 ` Bhupesh Sharma
2020-06-01 21:59 ` John Donnelly
2020-06-02 5:38 ` Prabhakar Kushwaha
2020-06-02 14:41 ` John Donnelly
2020-06-03 11:47 ` Prabhakar Kushwaha
2020-06-03 13:20 ` chenzhou
2020-06-03 15:30 ` John Donnelly
2020-06-03 19:47 ` Bhupesh Sharma
2020-06-04 7:14 ` Will Deacon [this message]
2020-06-04 17:01 ` Nicolas Saenz Julienne
2020-06-05 2:26 ` John Donnelly
2020-06-05 8:21 ` Nicolas Saenz Julienne
2020-06-19 2:32 ` John Donnelly
2020-06-19 8:21 ` chenzhou
2020-06-20 0:01 ` John Donnelly
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