linux-kernel - Re: Disabling physical RAM regions for testing

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 for Android: free password hash cracker in your pocket

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

Date:	Tue, 05 Aug 2014 08:26:01 -0400
From:	Austin S Hemmelgarn <ahferroin7@...il.com>
To:	madduck@...duck.net
CC:	linux kernel mailing list <linux-kernel@...r.kernel.org>
Subject: Re: Disabling physical RAM regions for testing

On 2014-08-05 07:40, martin f krafft wrote:
> Hello,
> 
> A NAS seems to be having RAM problems, leading me to want to swap
> out DIMMs until I found the offender; I'd rather not go to the rack
> every time I need to make a change.
> 
> Is there a way to declare a DIMM unavailable to Linux with a boot
> parameter? There is mem= and memmap= but i cannot figure them out.
> 
> I have two 4Gb DIMMs in there and I just want to disable one, then
> the other…
> 
> This is the e820 physical RAM map:
> 
> [    0.000000] e820: BIOS-provided physical RAM map:
> [    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009e7ff] usable
> [    0.000000] BIOS-e820: [mem 0x000000000009e800-0x000000000009ffff] reserved
> [    0.000000] BIOS-e820: [mem 0x00000000000e2000-0x00000000000fffff] reserved
> [    0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000bff8ffff] usable
> [    0.000000] BIOS-e820: [mem 0x00000000bff9e000-0x00000000bff9ffff] reserved
> [    0.000000] BIOS-e820: [mem 0x00000000bffa0000-0x00000000bffaa5ff] ACPI data
> [    0.000000] BIOS-e820: [mem 0x00000000bffaa600-0x00000000bffdffff] ACPI NVS
> [    0.000000] BIOS-e820: [mem 0x00000000bffe0000-0x00000000bfffffff] reserved
> [    0.000000] BIOS-e820: [mem 0x00000000e0000000-0x00000000efffffff] reserved
> [    0.000000] BIOS-e820: [mem 0x00000000ffa00000-0x00000000ffffffff] reserved
> [    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000022fffffff] usable
> 
> But what do I do with those info?
> 
The e820 is probably not what you want to be looking at.  I would
suggest looking into memory hot-plug/hot-remove support, IIRC the
hot-remove support allows you to bring a bank offline.


Download attachment "smime.p7s" of type "application/pkcs7-signature" (2967 bytes)