From: Jie Zhang <jie.zhang@analog.com>
To: Jamie Lokier <jamie@shareable.org>
Cc: uClinux development list <uclinux-dev@uclinux.org>,
David Howells <dhowells@redhat.com>,
David McCullough <davidm@snapgear.com>,
Greg Ungerer <gerg@uclinux.org>, Paul Mundt <lethal@linux-sh.org>,
uclinux-dist-devel@blackfin.uclinux.org,
linux-kernel@vger.kernel.org
Subject: Re: [uClinux-dev] [PATCH] NOMMU: use copy_*_user_page() in access_process_vm()
Date: Wed, 25 Nov 2009 14:27:22 +0800 [thread overview]
Message-ID: <4B0CCE4A.5000602@analog.com> (raw)
In-Reply-To: <20091125061640.GB17203@shareable.org>
On 11/25/2009 02:16 PM, Jamie Lokier wrote:
> Mike Frysinger wrote:
>> From: Jie Zhang<jie.zhang@analog.com>
>>
>> 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
next prev parent reply other threads:[~2009-11-25 6:27 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-25 5:55 [PATCH] NOMMU: use copy_*_user_page() in access_process_vm() Mike Frysinger
2009-11-25 6:16 ` [uClinux-dev] " Jamie Lokier
2009-11-25 6:27 ` Jie Zhang [this message]
2009-11-25 6:51 ` Paul Mundt
2009-11-25 11:49 ` Jamie Lokier
2009-11-25 14:14 ` Jie Zhang
2009-11-25 18:39 ` Mike Frysinger
2009-11-25 6:19 ` David McCullough
2009-11-25 23:22 ` Greg Ungerer
2009-12-02 14:36 ` David Howells
2009-12-02 15:00 ` Jie Zhang
2009-12-02 14:45 ` David Howells
2009-12-02 15:07 ` Jie Zhang
2009-12-08 10:57 ` David Howells
2009-12-08 13:37 ` Jie Zhang
2009-12-08 14:19 ` David Howells
2009-12-08 14:30 ` Jie Zhang
2009-12-09 0:27 ` Mike Frysinger
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