Re: linux-2.3.31: drivers/char/drm/drmP.h does not allow 386 build

Rik Faith (faith@precisioninsight.com)
Thu, 9 Dec 1999 08:24:14 -0500 (EST)

On Thu 9 Dec 1999 13:14:32 +0000,
Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> > 2) Those interested implement the generic cmpxchg to work on 386
> > processors, if there is a need. At this time, I don't think this
> > work is justified unless someone else needs cmpxchg in the kernel.
>
> Alpha, Sparc64, everyone else with PCI and high end 3d cards. cmpxchg is
> very much an Intelism

Sure. On RISC machines, cmpxchg is easy to implement with the
load-locked/store-conditional instruction pair (the notion and use of
compare and exchange predates Intel's cmpxchg instruction). Richard
Henderson has already implemented a generic cmpxchg routine in the kernel
for Alpha and Intel, and it should be easy for someone to add one for the
Sparc64 and other modern processors that need it.

What I'm saying is that implementing a generic cmpxchg for _80386_ is not
justified at this time.

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