Re: [PATCH V3 2/2] kprobes: Mark OPTPROBES na for powerpc

2015-07-20 Thread Michael Ellerman
On Mon, 2015-07-20 at 08:41 -0500, Segher Boessenkool wrote: > On Mon, Jul 20, 2015 at 04:24:22PM +0530, Ananth N Mavinakayanahalli wrote: > > There is a potential gain to be had with a direct > > jump instead of a breakpoint, but the caveats need to be traded off > > with the complexity it brings

Re: [PATCH V3 2/2] kprobes: Mark OPTPROBES na for powerpc

2015-07-20 Thread Segher Boessenkool
On Mon, Jul 20, 2015 at 04:24:22PM +0530, Ananth N Mavinakayanahalli wrote: > There is a potential gain to be had with a direct > jump instead of a breakpoint, but the caveats need to be traded off > with the complexity it brings in. > > For now, mark OPTPROBES na for powerpc. If we haven't yet i

[PATCH V3 2/2] kprobes: Mark OPTPROBES na for powerpc

2015-07-20 Thread Ananth N Mavinakayanahalli
Kprobes uses a breakpoint instruction to trap into execution flow and the probed instruction is single-stepped from an alternate location. On some architectures like x86, under certain conditions, the OPTPROBES feature enables replacing the probed instruction with a jump instead, resulting in a si