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From: "Alexander van Heukelum" <heukelum@fastmail.fm>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Cyrill Gorcunov" <gorcunov@gmail.com>,
	"Ingo Molnar" <mingo@elte.hu>,
	"Jan Beulich" <jbeulich@novell.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC 0/6] x86 tip asm ENTRY,ENDPROC cleanup
Date: Sat, 14 Feb 2009 12:42:55 +0100	[thread overview]
Message-ID: <1234611775.19975.1300340003@webmail.messagingengine.com> (raw)
In-Reply-To: <49961178.6040101@zytor.com>

On Fri, 13 Feb 2009 16:34:00 -0800, "H. Peter Anvin" <hpa@zytor.com>
said:
> Alexander van Heukelum wrote:
> > 
> > Hi Cyrill,
> > 
> > I like this direction. If I understand correctly:
> > 
> > ENTRY/END or GLOBAL/END for data.
> > ENTRY/ENDPROC or GLOBAL/ENDPROC for functions.
> > 
> 
> Fine for functions, but it's really not okay to use the same macros for 
> data.  Furthermore, we need to consider special entry points that don't 
> behave like normal functions -- like system call or interrupt entry.
> 
> Why?  Because if we're compiling with frame pointers, we would like the 
> wrapper macros for functions to handle setting up and tearing down the 
> frame pointer, at least in the common case.

Hi Peter,

I see. But that would be new behaviour. I would propose to use
completely separate macro's to handle frame-setup code generation,
and keep ENTRY/GLOBAL/END/ENDPROC only for setting metadata and
alignment. I think it's worth it to spell out code-generating
macro's explicitly: there are not that many asm functions, and
quite a few of them would need special handling. I think noone
wants to see an ENDPROC_NOFRAMETEARDOWN ;).

The common-case example would look like this.

GLOBAL(c_callable_function)
        ENTER
        [asm-code]
        LEAVE
        ret
ENDPROC(c_callable_function)

Greetings,
    Alexander

> 	-hpa
-- 
  Alexander van Heukelum
  heukelum@fastmail.fm

-- 
http://www.fastmail.fm - I mean, what is it about a decent email service?


  parent reply	other threads:[~2009-02-14 11:43 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-13 21:50 [RFC 0/6] x86 tip asm ENTRY,ENDPROC cleanup Cyrill Gorcunov
2009-02-13 21:50 ` [RFC 1/6] x86: asm linkage - introduce GLOBAL macro Cyrill Gorcunov
2009-02-13 21:50 ` [RFC 2/6] x86: linkage - get rid of _X86 macros Cyrill Gorcunov
2009-02-13 21:50 ` [RFC 3/6] x86: copy.S - use GLOBAL,ENDPROC macros Cyrill Gorcunov
2009-02-13 21:50 ` [RFC 4/6] x86: pmjump " Cyrill Gorcunov
2009-02-13 21:50 ` [RFC 5/6] x86: compressed head_64 - use ENTRY,ENDPROC macros Cyrill Gorcunov
2009-02-13 21:50 ` [RFC 6/6] x86: compressed head_32 " Cyrill Gorcunov
2009-02-13 23:23 ` [RFC 0/6] x86 tip asm ENTRY,ENDPROC cleanup Alexander van Heukelum
2009-02-14  0:34   ` H. Peter Anvin
2009-02-14  8:21     ` Cyrill Gorcunov
2009-02-14 11:42     ` Alexander van Heukelum [this message]
2009-02-14 20:02       ` H. Peter Anvin
2009-02-19 16:13         ` Ingo Molnar

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