On Wed, 2017-02-08 at 09:50:51 UTC, Anju T wrote: > Current infrastructure of kprobe uses the unconditional trap instruction > to probe a running kernel. Optprobe allows kprobe to replace the trap with > a branch instruction to a detour buffer. Detour buffer contains instructions > to create an in memory pt_regs. Detour buffer also has a call to > optimized_callback() which in turn call the pre_handler(). > After the execution of the pre-handler, a call is made for instruction > emulation. The NIP is determined in advanced through dummy instruction > emulation and a branch instruction is created to the NIP at the end of > the trampoline. > > To address the limitation of branch instruction in POWER architecture, > detour buffer slot is allocated from a reserved area. For the time being, > 64KB is reserved in memory for this purpose. > > Instructions which can be emulated using analyse_instr() are the candidates > for optimization. Before optimization ensure that the address range > between the detour buffer allocated and the instruction being probed > is within +/- 32MB. > > Signed-off-by: Anju T Sudhakar <a...@linux.vnet.ibm.com> > Signed-off-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com> > Acked-by: Masami Hiramatsu <mhira...@kernel.org>
Series applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/51c9c0843993528bffc920c54c2121 cheers
