linux-kernel - Re: [PATCH 1/2] x86 e820: Check for exactmap appearance when parsing first memmap option

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Date:	Tue, 22 Jan 2013 11:33:06 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Thomas Renninger <trenn@...e.de>
Cc:	hpa@...or.com, x86@...nel.org, linux-kernel@...r.kernel.org,
	kexec@...ts.infradead.org, vgoyal@...hat.com, horms@...ge.net.au
Subject: Re: [PATCH 1/2] x86 e820: Check for exactmap appearance when parsing
 first memmap option

On Tue, Jan 22, 2013 at 7:20 AM, Thomas Renninger <trenn@...e.de> wrote:
>
> memmap=exactmap will throw away all original, but also until then
> user defined (through other provided memmap= parameters) areas.
> That means all memmap= boot parameters passed before a memmap=exactmap
> parameter are not recognized.
> Without this fix:
> memmap=x@y memmap=exactmap memmap=i#k
> only i#k would get recognized.
>
> This is wrong, this fix will only throw away all original e820 areas once
> when memmap=exactmap is found in the whole boot command line and before
> any other memmap= option is parsed.

Actually I put this patch already in for-x86-boot branch.

http://git.kernel.org/?p=linux/kernel/git/yinghai/linux-yinghai.git;a=commit;h=bd40ee79abf2351109ebd469b0b9ba6a8f3b0872

And will update change log to following to merge two change log.

---
Subject: [PATCH] x86: Handle multiple exactmaps and out of order exactmap

Current code expect that we only have one exactmap and exactmap need to
first one in memmap=.

memmap=exactmap will throw away all original entries, but also until
then user defined (through other provided memmap= parameters) areas.
That means all memmap= boot parameters passed before a memmap=exactmap
parameter are not recognized.

Without this fix:
        memmap=x@y memmap=exactmap memmap=i#k
only i#k would get recognized.  This is wrong.

This fix will scan the boot_command_line to find if there is exactmap at
first and only throw away all original e820 entries once, and then parse
other memmap= option.

-v2: incorporate change log from Thomas Renninger.

Signed-off-by: Yinghai Lu <yinghai@...nel.org>
Reviewed-by: Thomas Renninger <trenn@...e.de>
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