Re: [PATCH] arm64:kexec: Memstart should not be before the kernel start address

From: "Goel, Sameer" <sgoel@codeaurora.org>
To: AKASHI Takahiro <takahiro.akashi@linaro.org>,
	Geoff Levand <geoff@infradead.org>,
	timur@codeaurora.org, rruigrok@codeaurora.org,
	rruigrok@codeaurora.org, shankerd@codeaurora.org,
	kexec@lists.infradead.org
Subject: Re: [PATCH] arm64:kexec: Memstart should not be before the kernel start address
Date: Wed, 3 Aug 2016 17:44:30 -0600	[thread overview]
Message-ID: <d3e36e72-6975-c0fd-346d-5e7a79ba2e1a@codeaurora.org> (raw)
In-Reply-To: <20160802012551.GF7995@linaro.org>

Hi,
I am using vmlinux in this case. Usually the kernel code start is at a 
2M alignment from the System RAM start address. Since, kexec default 
options were not loading the image at the right address (same as the 
original kernel) and the API used to get iomem listing does not 
differentiate between the reserved and memblock addresses, I recommended 
that we look for the Kernel Code segment and round this down to get the 
right start address.
The above should not impact any current functionality or ignore any ram 
regions when booting the patched kernel.
I will report the patch on V2.
Thanks,
Sameer

On 8/1/2016 7:25 PM, AKASHI Takahiro wrote:
> On Mon, Aug 01, 2016 at 12:31:50PM -0700, Geoff Levand wrote:
>> Hi,
>>
>> On Fri, 2016-07-29 at 16:58 -0600, Goel, Sameer wrote:
>>> In our setup we cannot place the kernel starting at 0 address. So, it it
>>> placed at the first valid aligned address after placing the reserved
>>> regions in memory.
>>>
>>> The code from the change (https://patchwork.kernel.org/patch/8325221/)
>>> adds the reserved regions to iomem ranges. So, when the kexec tool is
>>> run it picks up the first reserved region as the start address for
>>> physical ram. When the kernel is loaded at this address, it fails to boot.
>>>
>>> So, I have put in a filter in the code that would pick up the right
>>> address of the primary kernel after this change was introduced.
>
> You're using Image, not vmlinux, right?
> I don't think that it's a good idea to add this sort of restriction
> because it is very system-specific.
> You'd better use "--mem-min=" parameter in your case.
> (In fact, this option doesn't work on the current arm64 port of kexec-tools,
> though.)
>
> Thanks,
> -Takahiro AKASHI
>
>>> Thanks,
>>> Sameer
>>
>>
>> Your patch no longer applies.  Please rebase it to my
>> for-merge-arm64-v2 branch and re-post.
>>
>> -Geoff
>>
>
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