On Sun, 2018-01-07 at 17:23 +0100, christophe leroy wrote: > CAUTION: This email originated from outside of the organization. Do not click > links or open attachments unless you recognize the sender and know the > content is safe. > > > Today, Linux kernel includes a workaround for CPU6 ERRATA on the 8xx > powerpc. > > This ERRATA exists on the 801, the 823, the 855/860 before revision C.0 > It doesn't concern any modern versions of the 8xx, neither the 860 past > and including rev C.0, nor the 866 nor the 885 > > This workaround complicates the TLBmiss and TLBerror handlers and make > the code more and more unreadable. > > Since this workaround addresses very old versions of the 8xx, I'd like > to get rid of it. Do you see any good reason to keep it today ? If not I > will come with a cleanup patch in the coming weeks. > > Another alternative would be to keep that workaround separated from the > rest of the code (ie using different registers to avoid/limit code > nesting), it would add a few cycles but would increase readability while > keeping the ERRATA in, allthought my preference goes to a complete > removal of the workaround. > > So, thanks to let me know your opinion on that.
Having done work on TLB Miss/Error, I agree the CPU6 errata is a pain. On all our 8xx (86x/850) we never had to use this errata so I am in favour for removing CPU6 Errata from recent kernels. Jocke
