Shared library in Genode must be position-independent?

[Stefan Kalkowski]

Hi Vincent,

just a short remark: when you do performance measurements on top of
Genode's i.MX6 base-hw platform, you should definitely upgrade to our
recent release 16.02. The initial contribution that enabled i.MX6 for
Genode did not encounter the L2 cache of this platform. So your
measurement comparisons will be misleading anyway as far as you did not
enabled the L2 cache yourself.
The recent release enables all four cores and the L2 cache for the
Wandboard target platform.

Regards
Stefan

On 02/29/2016 03:36 AM, Vincent Stone wrote:
> Hi all:
> I am using Genode to do some SSL encryption stuff. My dev-board is
> i.MX6Quad running Genode 15.02. The OpenSSL version is 1.0.1i. I test the
> Crypto speed of OpenSSL in Genode. It's very slow( 7MB/s for aes-128-gcm)
> comparing to OpenSSL in Linux (16MB/s for aes-128-gcm). Genode's OpenSSL
> doesn't use the assembly code version of some critical crypto function. It
> disable this option in libcrypto.mk. If I do the same to Linux OpenSSL, the
> performance goes down to 9MB/s. So I enable this option in libcrypto.mk.
> use Genode compiler to compile it. Everything seems ok. No compiler/linker
> errors. But the program can not run. MMU exception occurs before the main
> program start. It seems that something goes wrong during the library
> loading. I am really confused.
> Why does Genode disable this assembly code option? ( I can only find a
> 1-sentence explaination on Genode release notes 12.08
> <http://genode.org/documentation/release-notes/12.08>
> 
> Because libcrypto provides certain optimized assembler functions, which
>> unfortunately are not expressed with position-independent code, we removed
>> this assembler code and build libcrypto with -DOPENSSL_NO_ASM
> 
> 
> I guess the loader of Genode can not handle load-time relocation for shared
> library so all shared library must be position independent. Am I right?
> 
> Thank you.
> 
> --
> Best wishes
> Vincent
> 
> 
> 
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-- 
Stefan Kalkowski
Genode Labs

http://www.genode-labs.com/ · http://genode.org/