Subject: Re: controlling mmap() cache attributes on i386?
To: Jonathan Stone <>
From: Jason Thorpe <>
List: tech-kern
Date: 09/19/1996 09:04:25
On Thu, 19 Sep 1996 01:47:37 -0700 
 Jonathan Stone <jonathan@DSG.Stanford.EDU> wrote:

 > The  x86 TLB entries seem to support this, other port's pmap
 > interface support setting bits to enable or disable caching
 > (e.g., sparc); yet I can't seem to find how to do this on i386.
 > Am I missing something obvious?

In machdep.c, look at bus_mem_map() ... look for the calls to 
pmap_changebit().  You basically want to set PG_N in the pte.

I'm not sure, exactly, how you'll massage this into the d_mmap routine, 
but that's how you make the mapping uncacheable, anyhow...

 -- save the ancient forests - -- 
Jason R. Thorpe                             
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