linux-kernel - Re: [PATCH 4/5 v2] x86 boot: show pfn addresses in hex not decimal in some kernel info printks

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Date:	Fri, 27 Jun 2008 22:43:41 +0200
From:	Denys Vlasenko <vda.linux@...glemail.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Johannes Berg <johannes@...solutions.net>,
	Paul Jackson <pj@....com>, hpa@...or.com,
	yhlu.kernel@...il.com, akpm@...ux-foundation.org, mingo@...e.hu,
	tglx@...utronix.de, steiner@....com, travis@....com,
	linux-kernel@...r.kernel.org, ying.huang@...el.com,
	andi@...stfloor.org
Subject: Re: [PATCH 4/5 v2] x86 boot: show pfn addresses in hex not decimal in some kernel info printks

On Wednesday 25 June 2008 17:19, Linus Torvalds wrote:
> The problem is that right now we absolutely _do_ rely on gcc checking the 
> string, and as such we're forced to use standard patterns, and standard 
> patterns _only_.

Can we have alternative printk?

 asmlinkage int printk(const char * fmt, ...)
         __attribute__ ((format (printf, 1, 2))) __cold;
+asmlinkage int custom_printk(const char * fmt, ...) __cold asm ("printk");

There you go. custom_printk() will not be checked by gcc.
No runtime overhead.

> And that means that %M isn't an option, but also that if  
> we want symbolic names we'd have to use %p, and not some extension.
> 
> But once you drop the 'standard patterns' requirement, I do think you 
> should drop it _entirely_, and not just extend it with some pissant 
> single-character unreadable mess.

It still makes sense to have some more common ones as single char
for size reasons.
--
vda
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