linux-kernel - Re: [PATCH] x86: make sure wakeup code is below 1M -v2

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Message-ID: <4AFBB72F.6070907@zytor.com>
Date:	Wed, 11 Nov 2009 23:20:15 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	ykzhao <yakui.zhao@...el.com>
CC:	Yinghai Lu <yinghai@...nel.org>, "Rafael J. Wysocki" <rjw@...k.pl>,
	Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	Len Brown <lenb@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	pm list <linux-pm@...ts.linux-foundation.org>
Subject: Re: [PATCH] x86: make sure wakeup code is below 1M -v2

On 11/11/2009 11:14 PM, ykzhao wrote:
> 
> In this patch the find_e820_area is used in the
> acpi_reserve_wakeup_memory, which is called after initializing the
> bootmem allocator.
> Can we still use the find_e820_area after the bootmem allocator is
> initialized? 

Obviously not: the bootmem allocator now thinks it owns memory, and it
wouldn't know not to allocate something that is later claimed by
find_e820_area.  Problem.

> It seems that the bootmem bitmap is also found by using the
> find_e820_area. But we don't update the reserved_early array any more.
> Maybe we will get the overlap address with the bootmem bitmap for the
> wakeup code.

Not just the bitmap, but any bootmem allocation could conflict...

	-hpa
-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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