linux-kernel - Re: [PATCH] Turn rdmsr, rdtsc into inline functions, clarify names

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Date:	Sun, 06 Aug 2006 13:52:01 +1000
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Andi Kleen <ak@....de>
Cc:	lkml - Kernel Mailing List <linux-kernel@...r.kernel.org>,
	dmitry.torokhov@...il.com
Subject: Re: [PATCH] Turn rdmsr, rdtsc into inline functions, clarify names

On Sun, 2006-08-06 at 05:16 +0200, Andi Kleen wrote:
> > 	Please reconsider.  This isn't about being pretty, it's about not
> > having hidden side-effects,
> 
> I wouldn't call it hidden, it's well defined in the architecture.

Sorry Andi, I'm not talking about the asm, which is fine.  I'm talking
about the function-style macro which alters its arguments directly.
It's very bad form.

	int a, b;
	rdtsc(a, b);

> > and having typechecking.
> 
> The existing code will already reject any non integer and I don't
> see a particular need to be more strict than that.

Um?

	u64 c;
	int a,b;

	rdtsc(&a, &b);
	rdtscl(c);

These macros are badly named and don't check for bad usage.  Sure, less
than 1% of uses is wrong at the moment, but I'm volunteering to fix them
because I think it sets a bad example and sets us up for more bugs.

I feel fairly strongly about this, but I'll drop the x86_64 changes.

Rusty.
-- 
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