Hi all (specifically Gabe and Jason),

I'm trying to use gem5 to reproduce the results of Spectre code (
https://github.com/crozone/SpectrePoC) in FS mode. It uses RDTSC/RDTSCP to
measure the timing of a load operation. I have exactly the same issue with
one previous post, the gem5 simply returns a fixed number for all the loads.


I noticed that two patches were recently updated which implemented
serialized RDTSC and RDTSCP (I assume RDTSCP wouldn't work correctly since
the behavior of TSC_AUX hasn't been well defined, but RDTSC should work?).
However, in my experiments, it still returns a fixed number for all loads
for both RDTSC and RDTSCP. I also tried Jason's method, added a flag in
decoder-ns.cc.inc and it didn't work (I may do it wrong. What I did was add
the line of code/recompile/run with a script).

I would like to know if I want RDTSC or RDTSCP work as expected what
changes should I make to the gem5 code? Before I found the related post,
I'm thinking to replace RDTSC/RDTSCP with curTick() inside the testing code,
but also I didn't figure out how to do this and not sure if this would
work. I'm new to gem5 so sorry if some questions don't make sense.

-Li

I newly joined the mailing list, so was not able to reply to the previous
posts.

FYI. The related post is:
https://www.mail-archive.com/[email protected]/msg24602.html

The related patches are:
https://www.mail-archive.com/[email protected]/msg24671.html
https://www.mail-archive.com/[email protected]/msg24670.html
https://www.mail-archive.com/[email protected]/msg24668.html
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