changeset e622a3e2ed14 in /z/repo/gem5
details: http://repo.gem5.org/gem5?cmd=changeset;node=e622a3e2ed14
description:
arm: Fix TLB ignoring faults when table walking
This patch fixes a case where the Minor CPU can deadlock due to the lack
of a response to TLB request because of a bug in fault handling in the
ARM
table walker.
TableWalker::processWalkWrapper is the scheduler-called wrapper which
handles deferred walks which calls to TableWalker::wait cannot
immediately
process. The handling of faults generated by processWalk{AArch64,LPAE,}
calls in those two functions is is different. processWalkWrapper
ignores
fault returns from processWalk... which can lead to ::finish not being
called on a translation.
This fix provides fault handling in processWalkWrapper similar to that
found in the leaf functions which BaseTLB::Translation::finish.
diffstat:
src/arch/arm/table_walker.cc | 16 +++++++++++++---
1 files changed, 13 insertions(+), 3 deletions(-)
diffs (29 lines):
diff -r 997be6ba467e -r e622a3e2ed14 src/arch/arm/table_walker.cc
--- a/src/arch/arm/table_walker.cc Tue Dec 02 06:08:09 2014 -0500
+++ b/src/arch/arm/table_walker.cc Tue Dec 02 06:08:11 2014 -0500
@@ -344,12 +344,22 @@
// We've got a valid request, lets process it
pending = true;
pendingQueue.pop_front();
+ // Keep currState in case one of the processWalk... calls NULLs it
+ WalkerState *curr_state_copy = currState;
+ Fault f;
if (currState->aarch64)
- processWalkAArch64();
+ f = processWalkAArch64();
else if ((_haveLPAE && currState->ttbcr.eae) || currState->isHyp ||
isStage2)
- processWalkLPAE();
+ f = processWalkLPAE();
else
- processWalk();
+ f = processWalk();
+
+ if (f != NoFault) {
+ curr_state_copy->transState->finish(f, curr_state_copy->req,
+ curr_state_copy->tc, curr_state_copy->mode);
+
+ delete curr_state_copy;
+ }
return;
}
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