Date: Wed, 13 Aug 2008 14:32:06 -0700
From: Arjan van de Ven <arjan@infradead.org>
To: "Langsdorf, Mark" <mark.langsdorf@amd.com>
Cc: "Ingo Molnar" <mingo@elte.hu>,
       "Linus Torvalds" <torvalds@linux-foundation.org>,
       <linux-kernel@vger.kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
       "Thomas Gleixner" <tglx@linutronix.de>
Subject: Re: [PATCH](retry 2) Re: invalidate caches before going into
 suspend
Message-ID: <20080813143206.07550498@infradead.org>
In-Reply-To: <6453C3CB8E2B3646B0D020C112613273C5AC6B@sausexmb4.amd.com>
References: <200808131141.18003.mark.langsdorf@amd.com>
	<200808131230.07581.mark.langsdorf@amd.com>
	<20080813175232.GA1127@elte.hu>
	<200808131333.17850.mark.langsdorf@amd.com>
	<20080813114229.118be446@infradead.org>
	<6453C3CB8E2B3646B0D020C112613273C5AC6B@sausexmb4.amd.com>
Organization: Intel
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On Wed, 13 Aug 2008 13:47:05 -0500
"Langsdorf, Mark" <mark.langsdorf@amd.com> wrote:

> > Mark Langsdorf <mark.langsdorf@amd.com> wrote:
> > > +	/* mask all interrupts, flush any and all caches, and
> > > halt */
> > > +	if (cpu_has_clflush)
> > > +		wbinvd_halt();
> > > +	else
> > > +		while (1)
> > > +			halt();
> > >  }
> > 
> > I like the asm version .. but this code makes me blink.
> > when you HAVE clflush you do wbinvd.
> > yeah I know it's correct but... it reads wonky ;)
> 
> It's the most convenient symbol to test against.  I
> suppose I should add a comment explaining it.
> 
> > also.. can we move that check into the wbinvd_halt() itself, so that
> > the callers don't need to care what is used to select it ?
> 
> irqflags.h doesn't guarantee the presence of boot_cpu_data, 
> so I wasn't able to make that check cleanly.  I could move
> the macro definition to process_??.c if that would better.
> 

it makes sense; it's hardly a hotpath, and making it simple to use
correctly is generally best ;)
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