linux-kernel - RE: [PATCH] crash dump: don't delete non-E820

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <88DC34334CA3444C85D647DBFA962C270FD7F507@SHSMSX102.ccr.corp.intel.com>
Date:	Mon, 5 Nov 2012 02:57:24 +0000
From:	"Zhang, Jun" <jun.zhang@...el.com>
To:	"H. Peter Anvin" <hpa@...or.com>
CC:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"x86@...nel.org" <x86@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Fleming, Matt" <matt.fleming@...el.com>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] crash dump: don't delete non-E820_RAM during init

Hello, Anvin
1) use "memmap=exactmap", which remove all ranges include ram and non-ram range. So my first patch reserve the non-ram range.
2)don't use " memmap=exactmap ", so it reserve all ranges. But we only need non-ram, so we need kernel to remove RAM, just as my second patch.


Best Regards!

Jun Zhang
Inet: 8821-4273
Dir.Tel: 86-21-6116-4273
Email: jun.zhang@...el.com


-----Original Message-----
From: H. Peter Anvin [mailto:hpa@...or.com] 
Sent: Monday, November 05, 2012 10:39 AM
To: Zhang, Jun
Cc: Thomas Gleixner; Ingo Molnar; x86@...nel.org; Andrew Morton; Fleming, Matt; Paul Gortmaker; linux-kernel@...r.kernel.org
Subject: Re: [PATCH] crash dump: don't delete non-E820_RAM during init

On 11/05/2012 02:37 AM, Zhang, Jun wrote:
> Hello, Gortmaker
> I will modify my subject. Thanks!
> 
> Hello, Anvin
> from our three options, I think third option is better. But in 3) option, there are two choose, 3.1) is like memmap=REMOVERAM, 3.2) is memmap=CRASHKDUMP.
> In 3.1) we maybe need ifdef/endif within the { } of the function (like exactmap).
> In 3.2) we can remove the ifdef/endif. 
> Which one is the better? Maybe you have a better solution, please share it. 
> Thanks!
> 
> Next is our three option.
> 1)  my patch.
> 2)  modify kexec, only pass two parameters -- memmap=544K@64K 
>     memmap=64964K@...68K, in kernel setup_memory_map, we can remove RAM 
>     range.
> 3)  add extra optional, 3.1) like memmap=REMOVERAM
>                    3.2) like memmap=CRASHKDUMP
> 

Again, 2 would be better because it is a localized change to kexec.  If that works I don't see why there is any reason to change anything else.

	-hpa