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Date: Sat, 17 Nov 2012 20:34:43 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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Subject: Re: [PATCH 3/8] add mem64_min/max control
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To: Yinghai Lu <yinghai@kernel.org>
Cc: Haren Myneni <hbabu@us.ibm.com>, Simon Horman <horms@verge.net.au>, kexec@lists.infradead.org, "Eric W. Biederman" <ebiederm@xmission.com>, Vivek Goyal <vgoyal@redhat.com>

On 11/17/2012 04:44 PM, Yinghai Lu wrote:
> On Sat, Nov 17, 2012 at 12:04 PM, Yinghai Lu <yinghai@kernel.org> wrote:
>> On Sat, Nov 17, 2012 at 12:25 AM, Eric W. Biederman
>> <ebiederm@xmission.com> wrote:
>>
>> then for setup data (boot param) and command line, we have to set extra ident
>> mapping for them in kernel arch/x86/kernel/head_64.S
>>
>
> find the solution for this one:
> We don't need to set ident map for boot_param and command line in head_64.S
>
> as we already get arch/x86/kernel/head64.c, and could use
> early_ioremap to access
> and copy them out.
>

I don't think that is feasible; we need access to this structure 
extremely early.  I think if you're using the 64-bit entry point it has 
to be an entry condition that those structures are mapped.  It simply 
becomes a precondition for using the 64-bit entry point.

	-hpa


-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


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