[hppa-linux] Qn on PA-RISC Page tables and TLB

Kumar kumar@ix.netcom.com
Sun, 28 Mar 1999 12:37:05 -0800 (PST)

On Thu, 25 Mar 1999, Craig Hada wrote:
> > 
> In the absense of a harware TLB walker, the page directory format can be
> structured by software to fit its needs. However, the TLB miss handler
> must reformat the bits to fit the format of the TLB insert instructions.
> To get maximum performace from the system, the TLB miss handlers must be
> made very efficient. The format of the page directory entry in the PA-RISC 
> Arch 1.1 book minimizes the work of the TLB miss handlers by aligning the
> fields to match the format of the TLB insert instructions.
> > 	
> > 
Is it necessary that the virtual to physical mappings in TLB be inserted
only in a tlb miss fault. Can I insert  entries in the anticipation that
there will be a fault soon, for example when I first enable 
virtual mode ? If not, there is a potential chicken and egg problem
because I will get a TLB miss fault as soon as I turn virtual mode on and
TLB miss fault handler has to run in virtual mode with translations
on.....and there aint any tranlations yet inserted ...you get the pitcure