using utrace for instruction tracing

[Jim Keniston]

On Wed, 2007-09-05 at 15:46 -0700, Dave Nomura wrote:
> I notice that the utrace documentation says that single-stepping is only 
> supported if ARCH_HAS_SINGLE_STEP/ARCH_HAS_BLOCK_STEP is supported.  My 
> googling found a note you sent the says it is supported on ia64 and ppc, 
> but not on x86 yet.  Any idea if there are any work underway to support 
> this on x86?
> 
> Frank: Is this a unacceptable, or can we live with no user instruction 
> tracing on x86 until support is added?  I'm not very familiar with how 
> PI ITRACE does single step tracing on x86, for kernel/user code tracing 
> but I know it is significantly different than the PPC.

I'm not sure what you're looking at, but utrace definitely supports
single-stepping on x86 -- and at least ppc64, x86_64, and s390 as well,
since uprobes runs on all those and uses single-stepping.

Jim