From 22b60c57e697289baa205f11b164f356363c2bee Mon Sep 17 00:00:00 2001
From: Gedare Bloom <gedare@rtems.org>
Date: Tue, 21 May 2013 11:40:11 -0500
Subject: x86: Squash outstanding walks when instructions are squashed. This is
 the x86 version of the ARM changeset baa17ba80e06. In case an instruction has
 been squashed by the o3 cpu, this patch allows page table walker to avoid
 carrying out a pending translation that the instruction requested for.

---
 src/arch/x86/pagetable_walker.cc | 37 ++++++++++++++++++++++++++++++++-----
 1 file changed, 32 insertions(+), 5 deletions(-)

(limited to 'src/arch/x86/pagetable_walker.cc')

diff --git a/src/arch/x86/pagetable_walker.cc b/src/arch/x86/pagetable_walker.cc
index 853e062e7..45f902999 100644
--- a/src/arch/x86/pagetable_walker.cc
+++ b/src/arch/x86/pagetable_walker.cc
@@ -139,11 +139,8 @@ Walker::recvTimingResp(PacketPtr pkt)
         delete senderWalk;
         // Since we block requests when another is outstanding, we
         // need to check if there is a waiting request to be serviced
-        if (currStates.size()) {
-            WalkerState * newState = currStates.front();
-            if (!newState->wasStarted())
-                newState->startWalk();
-        }
+        if (currStates.size())
+            startWalkWrapper();
     }
     return true;
 }
@@ -192,6 +189,36 @@ Walker::WalkerState::initState(ThreadContext * _tc,
     timing = _isTiming;
 }
 
+void
+Walker::startWalkWrapper()
+{
+    unsigned num_squashed = 0;
+    WalkerState *currState = currStates.front();
+    while ((num_squashed < numSquashable) && currState &&
+        currState->translation->squashed()) {
+        currStates.pop_front();
+        num_squashed++;
+
+        DPRINTF(PageTableWalker, "Squashing table walk for address %#x\n",
+            currState->req->getVaddr());
+
+        // finish the translation which will delete the translation object
+        currState->translation->finish(new UnimpFault("Squashed Inst"),
+                currState->req, currState->tc, currState->mode);
+
+        // delete the current request
+        delete currState;
+
+        // check the next translation request, if it exists
+        if (currStates.size())
+            currState = currStates.front();
+        else
+            currState = NULL;
+    }
+    if (currState && !currState->wasStarted())
+        currState->startWalk();
+}
+
 Fault
 Walker::WalkerState::startWalk()
 {
-- 
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