elatllat
Posts: 1337
Joined: Sat Dec 17, 2011 5:05 pm

rowhammer

Tue Mar 24, 2015 4:35 pm

The rowhammer test won't compile for the raspberrypi;

Code: Select all

make.sh
/tmp/ccC9UOyB.s: Assembler messages:
/tmp/ccC9UOyB.s:375: Error: bad instruction `clflush (r2)'
Are there even any routes to row hammering in the ARM instruction set?
SBC with 32GB RAM: https://hardkernel.com

FAQ : https://raspberrypi.stackexchange.com

Unanswered: https://www.raspberrypi.org/forums/search.php?search_id=unanswered

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Paeryn
Posts: 2747
Joined: Wed Nov 23, 2011 1:10 am
Location: Sheffield, England

Re: rowhammer

Tue Mar 24, 2015 5:38 pm

Well, the readme clearly states: The test should work on Linux or Mac OS X, on x86 only.

To run it on the RPi you'd have to at least change the inline x86 assembly into ARM equivalent.
She who travels light — forgot something.

elatllat
Posts: 1337
Joined: Sat Dec 17, 2011 5:05 pm

Re: rowhammer

Tue Mar 24, 2015 5:41 pm

Yes I am aware of that.
I linked to a page saying "ARM doesn’t have an unprivileged cache-flush instruction".
What I'm asking is "Are there [other] routes to row hammering in the ARM instruction set"?
SBC with 32GB RAM: https://hardkernel.com

FAQ : https://raspberrypi.stackexchange.com

Unanswered: https://www.raspberrypi.org/forums/search.php?search_id=unanswered

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Paeryn
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Joined: Wed Nov 23, 2011 1:10 am
Location: Sheffield, England

Re: rowhammer

Tue Mar 24, 2015 6:48 pm

Sorry, I misinterpreted your posting of the compilation error as asking for why it didn't compile.
She who travels light — forgot something.

ejolson
Posts: 3825
Joined: Tue Mar 18, 2014 11:47 am

Re: rowhammer

Wed Mar 25, 2015 4:26 pm

elatllat wrote:Yes I am aware of that.
I linked to a page saying "ARM doesn’t have an unprivileged cache-flush instruction".
What I'm asking is "Are there [other] routes to row hammering in the ARM instruction set"?
On Raspberry Pi 2B would the DMB memory barrier ARMv7 instruction allow hammering?

http://infocenter.arm.com/help/index.js ... 14041.html

elatllat
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Joined: Sat Dec 17, 2011 5:05 pm

Re: rowhammer

Mon Oct 24, 2016 1:42 pm

Looks like that's a yes;
It's only taken 31 years for someone to get around to testing it on the arm instruction set.
So are there any BGA ECC RAM chips for the rpi4?
or a Memory Encryption Unit?
SBC with 32GB RAM: https://hardkernel.com

FAQ : https://raspberrypi.stackexchange.com

Unanswered: https://www.raspberrypi.org/forums/search.php?search_id=unanswered

ejolson
Posts: 3825
Joined: Tue Mar 18, 2014 11:47 am

Re: rowhammer

Tue Oct 25, 2016 5:56 am

elatllat wrote:Looks like that's a yes;
It's only taken 31 years for someone to get around to testing it on the arm instruction set.
So are there any BGA ECC RAM chips for the rpi4?
or a Memory Encryption Unit?
ECC only provides a certain probability that memory corruption caused by rowhammer will be detected and corrected. The hardware issues related to refresh and circuit density are still present in modern ECC memories. Older systems based on Pentium 4 and Athlon II CPUs as well as older ARM based systems may be immune because of using lower density memory at slower data rates. It would be interesting to know which, if any, of the Raspberry Pi computers have this hardware bug.

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