[PATCH] ARM: ptrace: fix ptrace_read_user for !CONFIG_MMU platforms

[Will Deacon]

On Tue, Feb 21, 2012 at 10:10:52AM +0000, Russell King - ARM Linux wrote:
> On Tue, Feb 21, 2012 at 10:00:41AM +0000, Will Deacon wrote:
> > On Tue, Feb 21, 2012 at 08:36:12AM +0000, Russell King - ARM Linux wrote:
> > > Maybe no one uses a debugger for uclinux programs?
> > 
> > I confess to finding this by inspection rather than a debugging failure.
> 
> There is another explanation - that is no one in the uclinux world uses
> mainline kernels, and this bug has been fixed ages ago in some uclinux
> kernel tree.
> 
> That directly raises the question of the value of having the uclinux
> baggage in the mainline kernel if no one is using mainline kernels for
> uclinux work.  If the uclinux folk aren't willing to pass up bug fixes,
> then having it in mainline is, frankly, a waste of space.

I know the validation guys in ARM use mainline kernels for bringup on
MMU-less CPUs (ok, they have extra patches on top but these tend to be
platform-specific hacks since they're running on an RTL emulator. Plus they do
periodically rebase onto new release kernels.). Debugging tends to be at a
much lower level than GDB can provide though (i.e. waveforms), so this would
have gone un-noticed.

I think it's worth keeping the support, particularly in light of the recent
interest in M-class CPUs on the list.

Will