On Mon, Aug 26, 2019 at 8:57 AM Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx> wrote: > > On Sun, Aug 25, 2019 at 10:37 PM Song Liu <liu.song.a23@xxxxxxxxx> wrote: > > On Fri, Aug 23, 2019 at 7:04 PM Jakub Kicinski wrote: > > > From: Jiong Wang <jiong.wang@xxxxxxxxxxxxx> > > > > > > NFP is using Local Memory to model stack. LM_addr could be used as base of > > > a 16 32-bit word region of Local Memory. Then, if the stack offset is > > > beyond the current region, the local index needs to be updated. The update > > > needs at least three cycles to take effect, therefore the sequence normally > > > looks like: > > > > > > local_csr_wr[ActLMAddr3, gprB_5] > > > nop > > > nop > > > nop > > > > > > If the local index switch happens on a narrow loads, then the instruction > > > preparing value to zero high 32-bit of the destination register could be > > > counted as one cycle, the sequence then could be something like: > > > > > > local_csr_wr[ActLMAddr3, gprB_5] > > > nop > > > nop > > > immed[gprB_5, 0] > > > > > > However, we have zero extension optimization that zeroing high 32-bit could > > > be eliminated, therefore above IMMED insn won't be available for which case > > > the first sequence needs to be generated. > > > > > > Fixes: 0b4de1ff19bf ("nfp: bpf: eliminate zero extension code-gen") > > > Signed-off-by: Jiong Wang <jiong.wang@xxxxxxxxxxxxx> > > > Reviewed-by: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx> > > I haven't looked into the code yet. But ^^^ should be > > > > Signed-off-by: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx> > > > > right? > > I prefer Review on code I review, ack on code I ack, and sign-off on > code I co-author. I believe if you're sending somebody else patch you have to add your SOB in addition to their 'Author:' and their SOB fields.