Re: Execute in place

From: Robin Getz
Date: Thu May 03 2007 - 08:10:42 EST


On Wed 2 May 2007 10:04, Hugh Dickins pondered:
> On Tue, 1 May 2007, Phillip Susi wrote:
> > I seem to remember seeing some patches go by at some point that
> > allowed one of the rom type embeded system filesystems to directly
> > execute binaries out of the original rom memory rather than copying
> > them to ram first, then executing from there. I was wondering if
> > rootfs or tmpfs support such execute in place today, or if
> > binaries executed from there have their code segments duplicated
> > in ram?
>
> Only ext2 supports it today: see Documentation/filesystems/xip.txt
>

Depends on if it is a noMMU or MMU platform.

Since noMMU platforms can't re-arrange non-contiguous blocks (which appears in
a read/write ext2 file system) we need to use a read only romfs which
applications are guaranteed to be contiguous by design.

I don't think the noMMU case is documented in xip.txt

-Robin
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