Message-ID: <47901E89.4060001@zytor.com>
Date: Thu, 17 Jan 2008 22:35:37 -0500
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Harvey Harrison <harvey.harrison@gmail.com>
CC: Roland McGrath <roland@redhat.com>, Ingo Molnar <mingo@elte.hu>,
       LKML <linux-kernel@vger.kernel.org>,
       Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] x86: Use v8086_mode helper, trivial unification
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Harvey Harrison wrote:
> 
> What do you think of:
> 
> /*
>  * (unsigned long)regs looks strange, but it's correct for x86_32.  x86_32 CPUs
>  * don't save the ss and esp registers if the CPU is already in kernel mode
>  * when it traps.  So &regs happens to be esp.  Valid only for kernel-mode
>  * pt_regs.
>  */
> static inline unsigned long stack_pointer(struct pt_regs *regs)
> {
> #ifdef CONFIG_X86_32
> 	return (unsigned long)regs;
> #else
> 	return regs->sp;
> #endif
> }
> 

Please highlight the last sentence better.  That's a user restriction 
and a highly important one.

	-hpa
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