linux-kernel - Re: [i386] Questions regarding provisional page tables initialization

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Message-ID: <jed4zbeqa4.fsf@sykes.suse.de>
Date:	Mon, 02 Jul 2007 00:02:27 +0200
From:	Andreas Schwab <schwab@...e.de>
To:	"Ahmed S. Darwish" <darwish.07@...il.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [i386] Questions regarding provisional page tables initialization

"Ahmed S. Darwish" <darwish.07@...il.com> writes:

>         page_pde_offset = (__PAGE_OFFSET >> 20)
> 	movl %ecx,(%edx)			/* Store identity PDE entry */
> 	movl %ecx,page_pde_offset(%edx)		/* Store kernel PDE entry */
>
> Why the pde_offset is PAGE_OFFSET >> 20 instead of PAGE_OFFSET >> 22 ?
> * 22 to right shift the whole page_shift (12) and pgdir_shift (10) bits.

4 is the element size.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@...e.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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