The generic and x86 code for user_regset went into Linus's kernel tree today, destined for the 2.6.25 release. I'm very grateful to Ingo Molnar, who helped this happen via the x86.git tree. I've also had some positive feedback from the powerpc maintainer, and expect the powerpc user_regset code to go in upstream soon as well.
If you are interested in utrace and you ever use an arch other than x86 and powerpc, now is the time to step forward as an arch advocate. If you are not confident you can do the kernel work, it is still a help to be the advocate for your arch and get help writing the code. If you can do the testing and work through some details with me, I will be glad to help out with writing the arch code. This is the first important milestone on the way to get utrace code into the upstream kernel. There is much more hard work ahead. Thanks, Roland
