From 3cd0b1f6a6873ef06351dd49f3c7697175303371 Mon Sep 17 00:00:00 2001 From: Andrew Bardsley Date: Tue, 2 Dec 2014 06:08:11 -0500 Subject: [PATCH] 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. --- src/arch/arm/table_walker.cc | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/src/arch/arm/table_walker.cc b/src/arch/arm/table_walker.cc index 30fdf9811..6a0f0144a 100644 --- a/src/arch/arm/table_walker.cc +++ b/src/arch/arm/table_walker.cc @@ -344,12 +344,22 @@ TableWalker::processWalkWrapper() // 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; } -- 2.30.2