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Subject: Re: fsl booke MM vs. SMP questions
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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> Why do you want to clear the reservation here? 
> 
> Coming out of some code path with the reservation still held 
> can only affect buggy code (someone doing st[dw]cx. before 
> l[dw]arx) AFAIK.

And buggy CPUs :-)

Seriously, lots of CPU implementations don't test the address for local
lwarx stwcx. so if your kernel code "replaces" a reservation with
another that is left set, the userland stwcx. might well succeed which
is bogus.

Ben.