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From:   Andi Kleen <ak@linux.intel.com>
To:     Linus Torvalds <torvalds@linux-foundation.org>
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Subject: Re: [PATCH 3/7] x86/mm/init: pass unconverted symbol addresses to
 free_init_pages()
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> [ Goes around and rummages ]
> 
> Oh, never mind, looking around reminded me why: we want to map the
> kernel text in the top 31 bits, so that we can use the faster
> -mcmodel=kernel because all symbols fit in sign-extended 32 bits.
> 
> Maybe there was some other reason too, but I think that's it.

No that was the only reason.

Large code model would be extremely expensive, and PIC linked
kernel also had some issues. So we ended up with this set up.

-Andi