Messages in this thread | | | From | David Howells <> | Subject | Re: [PATCH] NOMMU: use copy_*_user_page() in access_process_vm() | Date | Tue, 08 Dec 2009 14:19:27 +0000 |
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Jie Zhang <jie.zhang@analog.com> wrote:
> I agree on using 0 instead of NULL. But for !MMU, I think, vaddr is always as > same as addr. So we don't need to pass it?
FRV flushes the vaddr because in MMU mode the cache flush instructions take virtual addresses, so if we pass addr as vaddr, I can use the same cache flush code for both modes. I suspect it makes little difference to the amount of code if we pass that rather than 0, as the value is already computed, and either way, it's going to take one instruction to set up the argument.
Note that Blackfin assumes that it may use the dst address for flushing - an assumption that isn't valid in MMU mode with a VIVT cache (which I presume Blackfin isn't, but other CPUs are).
David
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