On Mon, Oct 03, 2005 at 09:15:52AM -0400, Daniel Jacobowitz wrote: > > > Well, the flag is not really to specify whether the common code is to be > > > used or not. It's about whether the TLB is like that of the R4k. > > > Actually it's always been a mystery for me why the common code cannot be > > > used for the SB1, but perhaps there is something specific that I could > > > only discover in that "SB-1 Core User Manual" that I yet have to see, > > > sigh... > > > > > > Of course if your TLB is indeed different from that of the R4k, then you > > > shouldn't be setting cp0.config.mt to 1 in the first place... > > > > The reason was primarily the tiny bit of extra performance because the > > SB1 doesn't need the hazard handling overhead. Also tlb-sb1 has a few > > changes that are needed to initialize a TLB in undefined state after > > powerup. That was needed to run Linux on firmware-less SB1 cores. > > FYI, all I have is a piece of hard evidence: this patch was the > difference between not booting and booting for a Sentosa with CFE. > Which isn't firmwareless and isn't a tiny bit of extra performance > issue. > > I'll try to give CVS HEAD a shot this week sometime. Just as reminder for everybody - CVS is dead and frozen, the action is playing on git now ... Ralf
