From owner-freebsd-arch  Sat Mar 16 12:22:57 2002
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Date: Sat, 16 Mar 2002 12:22:22 -0800
From: Terry Lambert <tlambert2@mindspring.com>
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To: Bruce Evans <bde@zeta.org.au>
Cc: "M. Warner Losh" <imp@village.org>, des@ofug.org,
	arch@FreeBSD.ORG
Subject: Re: HEADS UP: caddr_t sweep
References: <20020316225716.I28305-100000@gamplex.bde.org>
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Bruce Evans wrote:
> On Fri, 15 Mar 2002, M. Warner Losh wrote:
> > In message: <xzp7kodxki8.fsf@flood.ping.uio.no>
> >             Dag-Erling Smorgrav <des@ofug.org> writes:
> > : I'm preparing a sweep that will remove incorrect caddr_t casts in
> > : copy{in,out,str,instr}(), bcopy() and bzero() calls in the kernel.
> > ...
> >
> > i'd like to take a look at this patch before you commit it please.
> > There are many driver uses of bcopy that are non-obvious and likely
> > should be bus_space_read instead...
> 
> Maybe limit it to copy* and other userland interfaces (mmap?) then.
> There are also some bcopies which should be struct assignments.


This issue was mentioned at the BSDCon Developer's Summit
as the main issue in the limitation of Alpha systems to
2G of physical RAM.

I think it's important to address this issue.  Right now,
there is a similar limitation on Intel at 4G, for 32 bit
PCI cards, where the bus_space code is not being used to
keep the transfers in the low 4G of memory.

-- Terry

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