Re: [PATCH 3/8] add mem64_min/max control

H. Peter Anvin
2012-11-18T04:34:52Z

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.