cvs commit: src/sys/conf ldscript.i386 src/sys/i386/i386 bios.c genassym.c locore.s machdep.c mp_machdep.c mpboot.s pmap.c src/sys/i386/include pmap.h vmparam.h

[John Baldwin]

On 06-Oct-2003 Peter Wemm wrote:
> John Baldwin wrote:
>> 
>> On 04-Oct-2003 Peter Wemm wrote:
>> > John Baldwin wrote:
>> >  
>> >> On 01-Oct-2003 Peter Wemm wrote:
>> >> > peter       2003/10/01 16:46:08 PDT
>> > 
>> >> >   Log:
>> >> >   Commit Bosko's patch to clean up the PSE/PG_G initialization to and
>> >> >   avoid problems with some Pentium 4 cpus and some older PPro/Pentium2
>> >> >   cpus.  There are several problems, some documented in Intel errata.
>> > 
>> >> What does KERNBASE map to now?  4mb?
>> > 
>> > Nope.  KERNBASE is unchanged.  What is different now is that the fixed 1MB
>> > offset (pa = 1MB, va = KERNBASE + 1mb) is now 4MB and available via the
>> > KERNLOAD variable.  This becomes 2MB on a PAE configuration kernel.
>> 
>> So does KERNBASE + foo still map to PA foo for the lower 1 meg?
> 
> Yes, but the RAM part is readonly.  The isa hole and any ram->640K hole
> and address zero is read/write.  There are no devices under the ram section
> though, so the pmap_mapdev() tweaks for the first 1MB should be ok still.

Ok.  So the KERNBASE stuff is R/O and usually pmap_mapdev() maps things
R/W?

-- 

John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/