On Thu, Dec 22, 2011 at 03:04:47PM +0530, K.Prasad wrote: > On Wed, Dec 21, 2011 at 11:55:02AM +1100, David Gibson wrote: > > On Thu, Dec 08, 2011 at 04:53:30PM +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. > > > > Hrm. I had assumed the reason there wasn't a feature bit for EXACT > > originally was that EXACT breakpoints were *always* supposed to be > > supported by the new interface. > > > > Okay. Although BookS doesn't support EXACT breakpoints, it is possible > (after the introduction of new hw-breakpoint interfaces) to request for > a breakpoint of length 1 Byte.
Hrm. An EXACT breakpoint is not exactly the same as a range breakpoint of length 1 (consider unaligned accesses). But despite that, it should be possible to implement exact breakpoints on Book3S server hardware with some software filtering. And since that leaves no hardware that *can't* implement exact breakpoints (directly or indirectly), I'm not yet convinced of the need for a flag bit. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev