Re: [PATCH] VM routine fixes

From: David Woodhouse
Date: Wed Nov 10 2004 - 20:22:45 EST

On Wed, 2004-11-10 at 11:01 -0800, Andrew Morton wrote:
> Why _does_ !CONFIG_MMU futz around with page counts in such weird ways
> anyway? Why does it have requirements for higher-order pages which differ
> from !CONFIG_MMU?

Because in the absence of an MMU, an mmap of a large region (like an
executable) has to be satisfied by a large enough allocation followed by
a read.

> If someone could explain the reasoning behind the current code, and the FRV
> enhancements then perhaps we could work something out.

I think these parts aren't FRV-specific; they're the fixes required to
do proper shared readable mmap with !CONFIG_MMU. That was a prerequisite
for the ELF-FDPIC executable format, which allows real shared libraries
on uClinux.


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