From e2507407b17188dca802082434cfe0230d9bfa61 Mon Sep 17 00:00:00 2001 From: Giacomo Gabrielli Date: Fri, 11 Feb 2011 18:29:35 -0600 Subject: O3: Enhance data address translation by supporting hardware page table walkers. Some ISAs (like ARM) relies on hardware page table walkers. For those ISAs, when a TLB miss occurs, initiateTranslation() can return with NoFault but with the translation unfinished. Instructions experiencing a delayed translation due to a hardware page table walk are deferred until the translation completes and kept into the IQ. In order to keep track of them, the IQ has been augmented with a queue of the outstanding delayed memory instructions. When their translation completes, instructions are re-executed (only their initiateAccess() was already executed; their DTB translation is now skipped). The IEW stage has been modified to support such a 2-pass execution. --- src/sim/tlb.hh | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'src/sim/tlb.hh') diff --git a/src/sim/tlb.hh b/src/sim/tlb.hh index 1512bc0fa..253f12072 100644 --- a/src/sim/tlb.hh +++ b/src/sim/tlb.hh @@ -1,4 +1,16 @@ /* + * Copyright (c) 2011 ARM Limited + * All rights reserved. + * + * The license below extends only to copyright in the software and shall + * not be construed as granting a license to any other intellectual + * property including but not limited to intellectual property relating + * to a hardware implementation of the functionality of the software + * licensed hereunder. You may use the software subject to the license + * terms below provided that you ensure that this notice is replicated + * unmodified and in its entirety in all distributions of the software, + * modified or unmodified, in source code or in binary form. + * * Copyright (c) 2006 The Regents of The University of Michigan * All rights reserved. * @@ -64,6 +76,12 @@ class BaseTLB : public SimObject virtual ~Translation() {} + /** + * Signal that the translation has been delayed due to a hw page table + * walk. + */ + virtual void markDelayed() = 0; + /* * The memory for this object may be dynamically allocated, and it may * be responsible for cleaning itself up which will happen in this -- cgit v1.2.3