using utrace for instruction tracing

[Dave Nomura]

This is what I found when I googled ARCH_HAS_SINGLE_STEP x86 utrace
http://lkml.org/lkml/2007/2/21/264
Date 	Wed, 21 Feb 2007 13:18:11 -0500
>From 	Jeff Dike <>
Subject 	Re: [PATCH] UML utrace support, step 1

......

> > +#define ARCH_HAS_SINGLE_STEP	(1)
> 
> Note you'll eventually want to define the block-step macro and functions
> depending on subarch.  (ia64 supports it, and x86 one day will.)

I guess I didn't read the comment carefully enough.  I think this mail 
is from a guy implementing utrace for x86 and is saying that block 
stepping isn't supported.

Jim Keniston wrote:
> 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
>
>   


-- 
Dave Nomura
LTC Linux Power Toolchain