Re: A simple question about readw, readw and the like

From: Jamie Lokier (lk@tantalophile.demon.co.uk)
Date: Thu Jul 27 2000 - 08:12:54 EST


David S. Miller wrote:
> Derefencing the return pointer from ioremap() and not using the readw
> etc. interfaces is almost guarenteed to not work on any platform
> other than x86. On Sparc64 for example the return from ioremap()
> happens to be a physical address and will OOPS on you on any direct
> derefence of that pointer, readw() and friends do the access in the
> correct manner.

Has anyone considered offsetting the ioremap() return address and
subtracting that offset in readl() et al., to catch bogus drivers that
dereference directly?

I'd guess most drivers are tested only on x86 -- this is one way to
check that they're getting at least one portability issue right.

-- Jamie

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