From: Ralf Baechle <ralf@linux-mips.org>
To: Kip Walker <kwalker@broadcom.com>
Cc: linux-mips@linux-mips.org
Subject: Re: break_cow and cache flushing
Date: Thu, 17 Oct 2002 04:09:56 +0200 [thread overview]
Message-ID: <20021017040956.B26285@linux-mips.org> (raw)
In-Reply-To: <3DADFC0B.81C8C058@broadcom.com>; from kwalker@broadcom.com on Wed, Oct 16, 2002 at 04:53:47PM -0700
On Wed, Oct 16, 2002 at 04:53:47PM -0700, Kip Walker wrote:
To add a few technical details ...
> 1) 'flush_cache_page' seems to be intended for flushing virtually
> indexed dcaches when a virtual->physical mapping changes (based on
> PAddr)
Yes.
> 2) 'flush_page_to_ram' is also related to avoiding virtual aliasing in
> the dcache (based on VAddr)
Yes again.
Note that flush_page_to_ram is deprecated and should be implement as empty
function for all architecture and the other flushing mechanisms be used
instead.
> 3) 'flush_icache_page' seems to be intended for making the icache
> coherent with the dcache after an executable page has been filled
Yes.
> 4) 'break_cow' may copy an executable page that is marked executable,
> for example a stack page (which has VM_EXEC) and might contain a live
> signal trampoline
Yes.
> On a CPU with writeback physically indexed/tagged dcache and virtually
> indexed icache that isn't coherent with the dcache, (1) and (2) are NOPs
> and (3) must writeback the dcache and flush the icache.
Yes, where this is getting complicated by some CPUs where remote i-caches
are coherent but the local isn't.
Ralf
next prev parent reply other threads:[~2002-10-17 2:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-16 23:53 break_cow and cache flushing Kip Walker
2002-10-17 2:04 ` Ralf Baechle
2002-10-17 2:09 ` Ralf Baechle [this message]
2002-10-17 2:49 ` Nigel Weeks
2002-10-17 2:49 ` Nigel Weeks
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20021017040956.B26285@linux-mips.org \
--to=ralf@linux-mips.org \
--cc=kwalker@broadcom.com \
--cc=linux-mips@linux-mips.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.