From: "H. Peter Anvin" <hpa@zytor.com>
To: huang ying <huang.ying.caritas@gmail.com>
Cc: Ian Campbell <ijc@hellion.org.uk>,
"Huang, Ying" <ying.huang@intel.com>,
akpm@linux-foundation.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Andi Kleen <ak@suse.de>,
linux-kernel@vger.kernel.org,
Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: [PATCH -mm 1/3] i386 boot: replace boot_ioremap with enhanced bt_ioremap - enhance bt_ioremap
Date: Fri, 18 Jan 2008 09:54:08 -0500 [thread overview]
Message-ID: <4790BD90.9060303@zytor.com> (raw)
In-Reply-To: <851fc09e0801180654u6957f966g47c7629db6d4b2b0@mail.gmail.com>
huang ying wrote:
>
> If CONFIG_X86_PAE is defined, the set_pte, clear_pte etc will operate
> 3-level page tables, while on i386, the early page table is always
> 2-level, so set_pte, clear_pte etc functions can not be used here. The
> boot_ioremap use a trick to deal with this problem. The CONFIG_X86_PAE
> is undefined in arch/x86/mm/boot_ioremap_32.c unconditionally, so the
> 2-level page table handling function is always used.
>
> Is the method used by boot_ioremap better for Xen?
>
Eric Biederman had a patchset that makes a PAE kernel use PAE page
tables from the start. That is really The Right Thing[TM].
-hpa
next prev parent reply other threads:[~2008-01-18 15:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-15 5:45 [PATCH -mm 1/3] i386 boot: replace boot_ioremap with enhanced bt_ioremap - enhance bt_ioremap Huang, Ying
2008-01-18 8:48 ` Ian Campbell
2008-01-18 12:50 ` Ingo Molnar
2008-01-18 14:54 ` huang ying
2008-01-18 14:54 ` H. Peter Anvin [this message]
2008-01-18 15:54 ` Ian Campbell
2008-01-18 16:22 ` Ingo Molnar
2008-01-18 17:27 ` Jeremy Fitzhardinge
2008-01-18 17:45 ` Ian Campbell
2008-01-18 15:23 ` Ian Campbell
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