Hi Prasad, On Sat, 2009-03-21 at 23:55 +0530, K.Prasad wrote: > On Mon, Mar 16, 2009 at 06:19:36PM +0530, Subrata Modak wrote: > > Hi Prasad, > > > > On Thu, Mar 5, 2009 at 10:07 AM, <[email protected]> wrote: > > > > > Hi Ingo, > > > Please find the revised set of patches that implement Hardware > > > Breakpoint (or watchpoint) registers and an arch-specific implementation > > > for x86/x86_64. > > > > > > Changelog > > > --------- > > > The previous version of these patches were submitted through > > > http://article.gmane.org/gmane.linux.kernel/794870. The patches now > > > contain a new ftrace plugin for kernel symbol tracing using hardware > > > breakpoint registers. The patches are now re-based to -tip tree commit > > > e40aa382597b30c4d702951348500e812b4cb3d0. > > > > > > A small usage note on the plugin along with the description of the > > > breakpoint interfaces is included below. > > > > > > Kindly accept these patches to become a part of -tip tree. > > > > > > Description > > > ------------- > > > The Hardware Breakpoint registers can be used for tracing changes to a > > > variable or data location (even I/O ports in x86/x86_64) and will be > > > extremely helpful in debugging problems such as memory corruption. While > > > these registers have been used by user-space debuggers for long (through > > > 'ptrace' syscalls), Kgdb exploited them for kernel-space addresses. > > > > > > You have been recently posting these patches to LKML. Being one of the LTP > > users, you would be in a position to tell whether we can test this from LTP > > ś user space tests ? If yes, have you worked on some test development for > > this ? ;-) > > > > Regards-- > > Subrata > > > > The hardware breakpoint interfaces patch brings out two new interfaces - > to register/unregister kernel-space breakpoint requests. The user-space > counterpart is not exported and is used internally by the ptrace syscall. >
Thanks for explaining in details. > If the testsuite can execute only from the user-space then partial testing > through ptrace syscalls that operate over debug registers is possible. Is > this already a part of LTP? Yes, it is. There are couple of ptrace() syscall tests, here: http://ltp.cvs.sourceforge.net/viewvc/ltp/ltp/testcases/kernel/syscalls/ptrace/, You would probably like to give a look to them, to see how they can be modified/new-things-added to address the Hardware Breakpoint testing. > > It would however be a thorough approach to test the infrastructure > through kernel modules using the exported interfaces for function verification > and stress testing. I'm not sure if this is within LTP's scope. If yes, Yes, it is within LTP´s scope, where we have a separate section for Device Drivers here: http://ltp.cvs.sourceforge.net/viewvc/ltp/ltp/testcases/kernel/device-drivers/, The only difference in their way of execution, is, that they do not fall under default LTP run. Instead, users need to go to each of the sub-tests inside device drivers, and execute them in mutual exclusion. May be when all these tests mature, we can find ways to make these tests alone to run at once. The modules that you are talking about can very well fit in this infrastructure. > it would be an interesting thing to add after the patch is in mainline and > the limitations of the infrastructure are defined (porting the patches to > other architectures is one way of knowing them). > I would be eager to know that. > Apart from the startup selftest that is bundled with the ftrace plugin > (a basic sanity test that runs automatically at boot-time and enabled > through a config option) we haven't worked on any testcases yet. I hope when things stabilize from your end, you may/would be able to give some thoughts to this proposal as well. Regards-- Subrata > > Hope this helps. > > Thanks, > K.Prasad > > > ------------------------------------------------------------------------------ > Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are > powering Web 2.0 with engaging, cross-platform capabilities. Quickly and > easily build your RIAs with Flex Builder, the Eclipse(TM)based development > software that enables intelligent coding and step-through debugging. > Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com > _______________________________________________ > Ltp-list mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/ltp-list ------------------------------------------------------------------------------ Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are powering Web 2.0 with engaging, cross-platform capabilities. Quickly and easily build your RIAs with Flex Builder, the Eclipse(TM)based development software that enables intelligent coding and step-through debugging. Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com _______________________________________________ Ltp-list mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ltp-list
