From: Arnd Bergmann <arnd@arndb.de>
To: linuxppc-dev@ozlabs.org
Cc: Paul Mackerras <paulus@samba.org>, Christoph Hellwig <hch@lst.de>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC][POWERPC] Provide a way to protect 4k subpages when using 64k pages
Date: Tue, 11 Dec 2007 22:21:15 +0100 [thread overview]
Message-ID: <200712112221.17697.arnd@arndb.de> (raw)
In-Reply-To: <20071211155305.GA28055@lst.de>
On Tuesday 11 December 2007, Christoph Hellwig wrote:
> Using 4k pages should basically be a pre-process flag
> (which it already is as an implementation detail in your patch), and
> thus the proper way to mark it should be a personality flag. =A0This
> also means it could be implied by certain personalities, e.g. powerpc
> 32bit for full compatiblity. =A0 All these process would use plain mmap/
> mprotect to deal with the subpage protections.
If you want to make it a per-process flag, wouldn't a prctl bit be more
appropriate than a personality flag? That way you could at least set
it independent from other personality settings.
> At least ia64 and mips have multiple pages sizes already and I suspect
> more architectures will grow support for it.
Another related option might be the alternative page table layouts that
Martin Schwidefsky has implemented for concurrent 2/3/4-level page tables
on s390.
Arnd <><
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: linuxppc-dev@ozlabs.org
Cc: Christoph Hellwig <hch@lst.de>, Paul Mackerras <paulus@samba.org>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC][POWERPC] Provide a way to protect 4k subpages when using 64k pages
Date: Tue, 11 Dec 2007 22:21:15 +0100 [thread overview]
Message-ID: <200712112221.17697.arnd@arndb.de> (raw)
In-Reply-To: <20071211155305.GA28055@lst.de>
On Tuesday 11 December 2007, Christoph Hellwig wrote:
> Using 4k pages should basically be a pre-process flag
> (which it already is as an implementation detail in your patch), and
> thus the proper way to mark it should be a personality flag. This
> also means it could be implied by certain personalities, e.g. powerpc
> 32bit for full compatiblity. All these process would use plain mmap/
> mprotect to deal with the subpage protections.
If you want to make it a per-process flag, wouldn't a prctl bit be more
appropriate than a personality flag? That way you could at least set
it independent from other personality settings.
> At least ia64 and mips have multiple pages sizes already and I suspect
> more architectures will grow support for it.
Another related option might be the alternative page table layouts that
Martin Schwidefsky has implemented for concurrent 2/3/4-level page tables
on s390.
Arnd <><
next prev parent reply other threads:[~2007-12-11 21:21 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-07 6:09 [RFC][POWERPC] Provide a way to protect 4k subpages when using 64k pages Paul Mackerras
2007-12-07 12:03 ` Arnd Bergmann
2007-12-07 12:03 ` Arnd Bergmann
2007-12-11 15:53 ` Christoph Hellwig
2007-12-11 21:21 ` Arnd Bergmann [this message]
2007-12-11 21:21 ` Arnd Bergmann
2007-12-11 21:37 ` Paul Mackerras
2007-12-11 23:38 ` Benjamin Herrenschmidt
2007-12-11 23:38 ` Benjamin Herrenschmidt
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=200712112221.17697.arnd@arndb.de \
--to=arnd@arndb.de \
--cc=hch@lst.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@ozlabs.org \
--cc=paulus@samba.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.