l4 for 386

Sebastian Schoenberg schoenbg at sophia.inf.tu-dresden.de
Thu Nov 8 10:05:09 CET 2001


Well, sort of or not. You have a mirrored region for kernel-
accessed read-only memory regions where the kernel potentially might
write to. You don't need a mirrored region for all writable pages.

Seb



> -----Original Message-----
> From: Espen Skoglund [mailto:esk at ira.uka.de]
> Sent: Mittwoch, 7. November 2001 13:31
> To: Sebastian Schoenberg
> Cc: jhuntnz at users.sourceforge.net; l4-hackers at os.inf.tu-dresden.de
> Subject: RE: l4 for 386
> 
> 
> [Sebastian Schoenberg]
> > This can be done by using different regions for read and write
> > access.  For tasks where the write-protection is neccesary, a page
> > is mapped only to the writeable area if the page is writable in the
> > page-table.
> 
> I'm not sure I know what you mean here.  Are you suggesting that we
> divide the user-accessible virtual memory into two equally sized
> mirrored regions; one for read-only and one for read-write?
> 
> 	eSk
> 



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