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To: Adrian Chadd <adrian@freebsd.org>
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Cc: "Jayachandran C." <jchandra@freebsd.org>,
	Kostik Belousov <kostikbel@gmail.com>, Alexander Motin <mav@freebsd.org>,
	"freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org>
Subject: Re: svn commit: r225892 - head/sys/mips/mips
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On Oct 3, 2011, at 7:38 PM, Adrian Chadd wrote:

> On 4 October 2011 07:09, Andrew Duane <aduane@juniper.net> wrote:
>> The COP0_SYNC's should be there (should there also be one after the =
MTC0 in MipsKernIntr?). The ISA says a hazard is needed, so that should =
be reflected. I assume different platforms define COP0_SYNC for =
themselves as needed?
>=20
> Is one needed after the mtc0 after StartWaitSkip?

I don't think it matters.  The COP0_SYNC is needed when you want to =
flush the instruction pipeline so that changes to COP0 don't affect them =
'randomly'.  However, in this case.  Either we're setting a bit that's =
already set, which won't change anything, or we're setting a bit that's =
clear, which will just delay the delivery of the interrupt a few cycles. =
 The race where it happens before the wait instruction is handled by the =
rest of the patch.

Warner