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Subject: Re: linux-next: build failure after merge of the tip tree
From: Len Brown <lenb@kernel.org>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
        "H. Peter Anvin" <hpa@zytor.com>, linux-next@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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+static void mwait_idle(void)
+{
+       mwait_idle_with_hints(0, 0);
+}
+

The reason the patch above will crash Core2 machines is because
core2 machines don't support mwait_idle_with_hints().

The calling sequence for old and new MWAIT instructions is different.
The former must be invoked with interrupts enabled,
and the later can be invoked with interrupts disabled,
which is a feature that Linux takes advantage of.

thanks,
-Len