[parisc-linux] depi?

[Frank Rowand]

Philipp Rumpf wrote:
> 
> > This is just one of several recent messages dealing with the issues caused by
> > locating the kernel at virtual address 0xc0000000 instead of 0x00000000.  I
> > still don't understand why the kernel can't be at zero, even though several
> > people have tried to explain it to me.  Can anyone provide a clear
> > explanation?
> 
> Advantages of mapping the kernel at 0xc000 0000 (or 0x8000 0000/0xe000 0000)
> 

< stuff deleted >

> 
> Disadvantages
> 

   - C code that needs to run in real mode seems to be rather fragile, given
     Paul's recent experience with head.c.  (I think it was Paul.)

   - A single instance of code can't (easily) be coded to be able to run both
     in real mode and in virtual mode.

   - It's real easy to mis-code real mode assembly (eg. use the PA() macro when
     it shouldn't be used or don't use it when it should be used).

   - Issues with coherent I/O.

< stuff deleted >

-Frank