Stack: Tidy up some comments, a warning, and make stack extension consistent.

Do some minor cleanup of some recently added comments, a warning, and change
other instances of stack extension to be like what's now being done for x86.

3 files changed, 8 insertions, 19 deletions

diff --git a/src/arch/alpha/faults.cc b/src/arch/alpha/faults.cc
index b6a0d965e..c66c6f8ab 100644
--- a/src/arch/alpha/faults.cc
+++ b/src/arch/alpha/faults.cc
@@ -201,8 +201,8 @@ NDtbMissFault::invoke(ThreadContext *tc, StaticInstPtr inst)
     TlbEntry entry;
     bool success = p->pTable->lookup(vaddr, entry);
     if (!success) {
-        p->checkAndAllocNextPage(vaddr);
-        success = p->pTable->lookup(vaddr, entry);
+        if (p->fixupStackFault(vaddr))
+            success = p->pTable->lookup(vaddr, entry);
     }
     if (!success) {
         panic("Tried to access unmapped address %#x.\n", (Addr)vaddr);
diff --git a/src/arch/sparc/faults.cc b/src/arch/sparc/faults.cc
index 814a33bd3..01d57e627 100644
--- a/src/arch/sparc/faults.cc
+++ b/src/arch/sparc/faults.cc
@@ -643,8 +643,8 @@ FastDataAccessMMUMiss::invoke(ThreadContext *tc, StaticInstPtr inst)
     TlbEntry entry;
     bool success = p->pTable->lookup(vaddr, entry);
     if (!success) {
-        p->checkAndAllocNextPage(vaddr);
-        success = p->pTable->lookup(vaddr, entry);
+        if (p->fixupStackFault(vaddr))
+            success = p->pTable->lookup(vaddr, entry);
     }
     if (!success) {
         panic("Tried to access unmapped address %#x.\n", vaddr);
diff --git a/src/arch/x86/tlb.cc b/src/arch/x86/tlb.cc
index 9ba20f8d7..9d02a00c7 100644
--- a/src/arch/x86/tlb.cc
+++ b/src/arch/x86/tlb.cc
@@ -619,22 +619,11 @@ TLB::translate(RequestPtr req, ThreadContext *tc, Translation *translation,
                 TlbEntry newEntry;
                 bool success = p->pTable->lookup(vaddr, newEntry);
                 if (!success && mode != Execute) {
-                    // This may fail because for some reason the requested
-                    // address is not allocatable on the stack.  If it's a stack
-                    // address, then it's because the address fell outside of
-                    // max stack range and user should increase max size of
-                    // stack.  Otherwise, it could be a random address that was
-                    // not in the page table and not on the stack.  Either way,
-                    // you'll end up with a page fault.
-                    if (p->checkAndAllocNextPage(vaddr))
-                        // Might as well not check this if you failed to
-                        // allocate.  Partially nested this just so code
-                        // maintainers can understand this is a separate and
-                        // necessary step not sufficient just by reading return
-                        // value of checkAndAlloc call because there is a side
-                        // effect.  This call will populate (it's called by 
-                        // reference).
+                    // Check if we just need to grow the stack.
+                    if (p->fixupStackFault(vaddr)) {
+                        // If we did, lookup the entry for the new page.
                         success = p->pTable->lookup(vaddr, newEntry);
+                    }
                 }
                 if (!success) {
                     return new PageFault(vaddr, true, mode, true, false);