All of lore.kernel.org
 help / color / mirror / Atom feed
From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: user-mode-linux-devel@lists.sourceforge.net,
	Miklos Szeredi <miklos@szeredi.hu>, Jeff Dike <jdike@addtoit.com>,
	linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
	harvey.harrison@gmail.com
Subject: Re: [uml-devel] uml and -regparm=3
Date: Wed, 09 Jan 2008 18:45:53 -0800	[thread overview]
Message-ID: <478586E1.8010709@zytor.com> (raw)
In-Reply-To: <20080110023701.GB20813@one.firstfloor.org>

Andi Kleen wrote:
> On Wed, Jan 09, 2008 at 09:14:04PM -0500, Jeff Dike wrote:
>> On Wed, Jan 09, 2008 at 10:50:48PM +0100, Miklos Szeredi wrote:
>>>> FASTCALL is useless and should not make a difference. It enables
>>>> regparm on specific functions, but that should not make a difference
>>>> if it works or not.
>>> __down_write() in include/asm-x86/rwsem.h seems to assume, that the
>>> semaphore pointer is passed in %eax down to rwsem_down_write_failed(),
>>> so regparm does make a difference there.
>> And rwsem_down_write_failed seems to think it's getting the pointer in
>> %eax:
> 
> That's a left over from when it was called by magic inline assembly.
> I suspect it would be better to switch it just over to stack args
> for consistent and then declare it asmlinkage
> 

That seems to go in the wrong direction to me.  It would make more sense 
to gradually shift to asmlinkage actually being regparm=3.  This, of 
course, would require a different name (such as FASTCALL) until the 
conversion is complete -- even if done as a single patch series.

	-hpa

-------------------------------------------------------------------------
Check out the new SourceForge.net Marketplace.
It's the best place to buy or sell services for
just about anything Open Source.
http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Jeff Dike <jdike@addtoit.com>, Miklos Szeredi <miklos@szeredi.hu>,
	harvey.harrison@gmail.com, akpm@linux-foundation.org,
	linux-kernel@vger.kernel.org,
	user-mode-linux-devel@lists.sourceforge.net
Subject: Re: uml and -regparm=3
Date: Wed, 09 Jan 2008 18:45:53 -0800	[thread overview]
Message-ID: <478586E1.8010709@zytor.com> (raw)
In-Reply-To: <20080110023701.GB20813@one.firstfloor.org>

Andi Kleen wrote:
> On Wed, Jan 09, 2008 at 09:14:04PM -0500, Jeff Dike wrote:
>> On Wed, Jan 09, 2008 at 10:50:48PM +0100, Miklos Szeredi wrote:
>>>> FASTCALL is useless and should not make a difference. It enables
>>>> regparm on specific functions, but that should not make a difference
>>>> if it works or not.
>>> __down_write() in include/asm-x86/rwsem.h seems to assume, that the
>>> semaphore pointer is passed in %eax down to rwsem_down_write_failed(),
>>> so regparm does make a difference there.
>> And rwsem_down_write_failed seems to think it's getting the pointer in
>> %eax:
> 
> That's a left over from when it was called by magic inline assembly.
> I suspect it would be better to switch it just over to stack args
> for consistent and then declare it asmlinkage
> 

That seems to go in the wrong direction to me.  It would make more sense 
to gradually shift to asmlinkage actually being regparm=3.  This, of 
course, would require a different name (such as FASTCALL) until the 
conversion is complete -- even if done as a single patch series.

	-hpa

  reply	other threads:[~2008-01-10  2:46 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-09 21:01 [uml-devel] uml and -regparm=3 Miklos Szeredi
2008-01-09 21:01 ` Miklos Szeredi
2008-01-09 21:12 ` [uml-devel] " Andi Kleen
2008-01-09 21:12   ` Andi Kleen
2008-01-09 21:20   ` [uml-devel] " Miklos Szeredi
2008-01-09 21:20     ` Miklos Szeredi
2008-01-09 21:32     ` [uml-devel] " Andi Kleen
2008-01-09 21:32       ` Andi Kleen
2008-01-09 21:50       ` [uml-devel] " Miklos Szeredi
2008-01-09 21:50         ` Miklos Szeredi
2008-01-10  2:14         ` [uml-devel] " Jeff Dike
2008-01-10  2:14           ` Jeff Dike
2008-01-10  2:37           ` [uml-devel] " Andi Kleen
2008-01-10  2:37             ` Andi Kleen
2008-01-10  2:45             ` H. Peter Anvin [this message]
2008-01-10  2:45               ` H. Peter Anvin
2008-01-09 21:33     ` [uml-devel] " Adrian Bunk
2008-01-09 21:33       ` Adrian Bunk
2008-01-09 22:01 ` [uml-devel] " linux-os (Dick Johnson)
2008-01-09 22:01   ` linux-os (Dick Johnson)
2008-01-10  7:32 ` [uml-devel] " Ingo Molnar
2008-01-10  7:32   ` Ingo Molnar
2008-01-10  9:05   ` [uml-devel] " Miklos Szeredi
2008-01-10  9:05     ` Miklos Szeredi
2008-01-10  9:35     ` [uml-devel] " Ingo Molnar
2008-01-10  9:35       ` Ingo Molnar

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=478586E1.8010709@zytor.com \
    --to=hpa@zytor.com \
    --cc=akpm@linux-foundation.org \
    --cc=andi@firstfloor.org \
    --cc=harvey.harrison@gmail.com \
    --cc=jdike@addtoit.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=miklos@szeredi.hu \
    --cc=user-mode-linux-devel@lists.sourceforge.net \
    /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.