Re: [PATCH v2 6/8] xen/x86: Reorder .data and .init when linking

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 24/02/16 11:41, Jan Beulich wrote:
>>>> On 23.02.16 at 17:31, <andrew.cooper3@citrix.com> wrote:
>> In preparation for using superpage mappings, .data and .bss will both want to
>> be mapped as read-write.  By making them adjacent, they can share the same
>> superpage and will not require superpage alignment between themselves.
>>
>> While making this change, fix an exposed alignment bug.  __init_end only needs
>> page alignment, while .bss.stack_aligned needs STACK_SIZE alignment.
> Well, this has become a bug only with your changes (perhaps
> that what you mean with "fix an exposed alignment bug", but
> it reads as if there was a latent one, which isn't the case afaict).

It is a latent bug.  The alignment directive for .bss.stack_aligned was
part of .init rather than .bss

>
>>    .bss : {                     /* BSS */
>>         __bss_start = .;
>> +       . = ALIGN(STACK_SIZE);
> These two lines should be swapped - there's no point in starting
> the BSS ahead of the alignment, causing us to needlessly zero
> a few more pages during boot.

Will do.

~Andrew