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Re: [Xen-devel] [PATCH 18/18] x86: add multiboot2 protocol support for EFI platforms



>>> On 27.03.15 at 15:26, <daniel.kiper@xxxxxxxxxx> wrote:
> On Fri, Mar 27, 2015 at 01:36:32PM +0000, Jan Beulich wrote:
>> >>> On 27.03.15 at 14:06, <daniel.kiper@xxxxxxxxxx> wrote:
>> > On Tue, Mar 17, 2015 at 10:32:01AM +0000, Jan Beulich wrote:
>> >> >>> On 30.01.15 at 18:54, <daniel.kiper@xxxxxxxxxx> wrote:
>> >> > +        /* Skip Multiboot2 information fixed part */
>> >> > +        lea     MB2_fixed_sizeof(%ebx),%ecx
>> >>
>> >> Let's please not add more assumptions than necessary about stuff
>> >> being below 4G.
>> >
>> > I am not sure what do you mean by that.
>>
>> See the 32-bit register used for addressing here (and in many more
>> places)?
> 
> This is what I expected but I was confused because you were referring only
> here to this problem. Anyway, is it possible to do this in different way?
> Should we care if image is always loaded at 0x100000 right now? Even with
> Xen early boot code being relocatable loader could not load image higher
> than 0xffffffff - 14 MiB.

I don't understand what you're alluding to. Just use 64-bit registers
for memory accesses and LEAs, and be done. This will result in smaller
code as a benefit.

Jan


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