[RFC] Hardware Breakpoint support for systemtap translator

[Prerna Saxena]

Prerna Saxena wrote:
> Hi,
> The attached set patches enable systemtap translator to probe kernel 
> hardware breakpoints on x86.
> It introduces the following language constructs :
>
> 1. probe kernel.data(ADDRESS).write     {....}   : To probe writes at 
> the given address
> 2. probe kernel.data(ADDRESS).rw         {....}   : To probe read & 
> write access to the given address.
> 3. probe kernel.data("SYMBOL").write   {....}
> 4. probe kernel.data("SYMBOL").rw       {....}   : Similar to 1,2, but 
> using a symbol name as argument.
>
> These are agnostic to dwarf/debuginfo and depend on the hardware 
> breakpoint infrastructure for resolving symbols.
>
> Things that remain to be done :
> 1. Translator support for probing hardware breakpoints on other 
> architectures (ppc/s390 etc)
> 2. Implementation of userspace hardware breakpoints.
>
> I'm still testing it...Looking for comments and feedback :-)
>
Forgot to mention that the underlying kernel infrastructure is in -tip. 
Would advise ppl to try these patches on systems running -tip kernel 
only :-)

-- 
Prerna Saxena

Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India