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arm: Fix TLB ignoring faults when table walking

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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.
This commit is contained in:
Andrew Bardsley 2014-12-02 06:08:11 -05:00
parent e5e5b80690
commit 3cd0b1f6a6
1 changed files with 13 additions and 3 deletions
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16
src/arch/arm/table_walker.cc
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@ -344,12 +344,22 @@ TableWalker::processWalkWrapper()
// We've got a valid request, lets process it // We've got a valid request, lets process it
pending = true; pending = true;
pendingQueue.pop_front(); pendingQueue.pop_front();
// Keep currState in case one of the processWalk... calls NULLs it
WalkerState *curr_state_copy = currState;
Fault f;
if (currState->aarch64) if (currState->aarch64)
processWalkAArch64(); f = processWalkAArch64();
else if ((_haveLPAE && currState->ttbcr.eae) || currState->isHyp || isStage2) else if ((_haveLPAE && currState->ttbcr.eae) || currState->isHyp || isStage2)
processWalkLPAE(); f = processWalkLPAE();
else 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; return;
} }