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From: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Subject: Question about rdhwr emulation.
Date: Tue, 21 Oct 2008 18:03:39 -0700	[thread overview]
Message-ID: <48FE7BEB.80906@caviumnetworks.com> (raw)

I was looking at the rdhwr emulation code in genex.S and wondering about the following:

If cpu_has_vtag_icache is true we run handle_ri_rdhwr_vivt() instead of handle_ri_rdhwr().

And handle_ri_rdhwr_vivt() probes the tlb to see if the faulting instruction can be reached through the TLB, if it can the 'fast path' is taken, otherwise the 'slow path'.

Why is this probe of the TLB necessary?  Or perhaps more concisely under which conditions can I set cpu_has_vtag_icache to false (noting that for our cpu this is the only place cpu_has_vtag_icache is tested)?

Thanks in advance for enlightening me,
David Daney

             reply	other threads:[~2008-10-22  1:04 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-22  1:03 David Daney [this message]
2008-10-22  1:35 ` Question about rdhwr emulation Maciej W. Rozycki
2008-10-24 21:59   ` Ralf Baechle
2008-10-24 22:22     ` David Daney

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