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. 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? 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, 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). 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. 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
