On Fri, 2011-08-26 at 14:41 +1000, David Gibson wrote: > On Wed, Aug 24, 2011 at 09:41:43PM -0300, Thiago Jung Bauermann wrote: > > On Wed, 2011-08-24 at 14:00 +1000, David Gibson wrote: > > > On Tue, Aug 23, 2011 at 02:57:56PM +0530, K.Prasad wrote: > > > > On Tue, Aug 23, 2011 at 03:09:31PM +1000, David Gibson wrote: > > > > > On Fri, Aug 19, 2011 at 01:23:38PM +0530, K.Prasad wrote: > > > > > > > > > > > > While PPC_PTRACE_SETHWDEBUG ptrace flag in PowerPC accepts > > > > > > PPC_BREAKPOINT_MODE_EXACT mode of breakpoint, the same is not > > > > > > intimated to the > > > > > > user-space debuggers (like GDB) who may want to use it. Hence we > > > > > > introduce a > > > > > > new PPC_DEBUG_FEATURE_DATA_BP_EXACT flag which will be populated on > > > > > > the > > > > > > "features" member of "struct ppc_debug_info" to advertise support > > > > > > for the > > > > > > same on Book3E PowerPC processors. > > > > > > > > > > I thought the idea was that the BP_EXACT mode was the default - if the > > > > > new interface was supported at all, then BP_EXACT was always > > > > > supported. So, why do you need a new flag? > > > > > > > > > > > > > Yes, BP_EXACT was always supported but not advertised through > > > > PPC_PTRACE_GETHWDBGINFO. We're now doing that. > > > > > > I can see that. But you haven't answered why. > > > > BookS doesn't support BP_EXACT, that's why I suggested this flag. > > Surely you can support it with exactly the same sort of filtering > you're using for the 8-byte ranges now?
Yes, but to detect that the processor doesn't support BP_EXACT in hardware I'd have to send a ptrace request, and have it rejected. Only then I'd step back and simulate one with ranges. Considering that it's easy and backwards compatible to add a new flag to signal that BP_EXACT is not supported, I don't know why it would be better to go with the more convoluted process. -- []'s Thiago Jung Bauermann IBM Linux Technology Center _______________________________________________ Linuxppc-dev mailing list [email protected] https://lists.ozlabs.org/listinfo/linuxppc-dev
