linux-kernel - Re: [git pull] x86 fixes

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Message-ID: <4888E83E.8080702@zytor.com>
Date:	Thu, 24 Jul 2008 16:38:22 -0400
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [git pull] x86 fixes

Linus Torvalds wrote:
> 
> On Thu, 24 Jul 2008, Ingo Molnar wrote:
>> Hugh Dickins (1):
>>       x86: BUILD_IRQ say .text to avoid .data.percpu
>>
>> diff --git a/arch/x86/kernel/irqinit_64.c b/arch/x86/kernel/irqinit_64.c
>> index 0373e88..9414125 100644
>> --- a/arch/x86/kernel/irqinit_64.c
>> +++ b/arch/x86/kernel/irqinit_64.c
>> @@ -43,7 +43,7 @@
>>  
>>  #define BUILD_IRQ(nr)				\
>>  	asmlinkage void IRQ_NAME(nr);		\
>> -	asm("\n.p2align\n"			\
>> +	asm("\n.text\n.p2align\n"		\
>>  	    "IRQ" #nr "_interrupt:\n\t"		\
>>  	    "push $~(" #nr ") ; "		\
>>  	    "jmp common_interrupt");
> 
> I do not think this is a good idea AT ALL.
> 
> You need a ".previous" there too, otherwise any random C code that doesn't 
> _happen_ to change segments will now possibly put some random variable in 
> the .text segment.
> 
> And yes, dependign on just where the BUILD_IRQ() is, and what is around 
> it, and what compiler version we have, this bug may or may not show. But 
> it's still _wrong_.
> 
> I pulled it, will fix up by hand.

You're obviously right here; thanks for taking care of it.

	-hpa
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