Re: [uClinux-dev] [PATCH] NOMMU: use copy_*_user_page() in access_process_vm()

From: Jie Zhang
Date: Wed Nov 25 2009 - 01:27:37 EST


On 11/25/2009 02:16 PM, Jamie Lokier wrote:
Mike Frysinger wrote:
From: Jie Zhang<jie.zhang@xxxxxxxxxx>

The mmu code uses the copy_*_user_page() variants in access_process_vm()
rather than copy_*_user() as the former includes an icache flush. This is
important when doing things like setting software breakpoints with gdb.
So switch the nommu code over to do the same.

Reasonable, but it's a bit subtle don't you think?
How about a one-line comment saying why it's using copy_*_user_page()?

(If it was called copy_*_user_flush_icache() I wouldn't say anything,
but it isn't).

But I think it's well known in Linux kernel developers that copy_to_user_page and copy_from_user_page should do cache flushing. It's documented in Documentation/cachetlb.txt. I don't think it's necessary to replicate it here.


Jie
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