From a1ad9e652a1a8b0b7d8c5dd2229324792010f6f3 Mon Sep 17 00:00:00 2001
From: Gabe Black <gblack@eecs.umich.edu>
Date: Fri, 9 Sep 2011 01:01:43 -0700
Subject: 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.
---
 src/sim/faults.cc  |  2 +-
 src/sim/process.cc | 16 +++++++++-------
 src/sim/process.hh |  6 +++---
 3 files changed, 13 insertions(+), 11 deletions(-)

(limited to 'src/sim')

diff --git a/src/sim/faults.cc b/src/sim/faults.cc
index 8e9b8e094..3f1369bcc 100644
--- a/src/sim/faults.cc
+++ b/src/sim/faults.cc
@@ -61,7 +61,7 @@ void GenericPageTableFault::invoke(ThreadContext *tc, StaticInstPtr inst)
 {
     Process *p = tc->getProcessPtr();
 
-    if (!p->checkAndAllocNextPage(vaddr))
+    if (!p->fixupStackFault(vaddr))
         panic("Page table fault when accessing virtual address %#x\n", vaddr);
 
 }
diff --git a/src/sim/process.cc b/src/sim/process.cc
index bec33c70b..62b9b7002 100644
--- a/src/sim/process.cc
+++ b/src/sim/process.cc
@@ -329,29 +329,31 @@ Process::sim_fd_obj(int tgt_fd)
 }
 
 bool
-Process::checkAndAllocNextPage(Addr vaddr)
+Process::fixupStackFault(Addr vaddr)
 {
-    // if this is an initial write we might not have
+    // Check if this is already on the stack and there's just no page there
+    // yet.
     if (vaddr >= stack_min && vaddr < stack_base) {
         pTable->allocate(roundDown(vaddr, VMPageSize), VMPageSize);
         return true;
     }
 
-    // We've accessed the next page of the stack, so extend the stack
-    // to cover it.
+    // We've accessed the next page of the stack, so extend it to include
+    // this address.
     if (vaddr < stack_min && vaddr >= stack_base - max_stack_size) {
         while (vaddr < stack_min) {
             stack_min -= TheISA::PageBytes;
-            if(stack_base - stack_min > max_stack_size)
+            if (stack_base - stack_min > max_stack_size)
                 fatal("Maximum stack size exceeded\n");
-            if(stack_base - stack_min > 8*1024*1024)
+            if (stack_base - stack_min > 8 * 1024 * 1024)
                 fatal("Over max stack size for one thread\n");
             pTable->allocate(stack_min, TheISA::PageBytes);
             inform("Increasing stack size by one page.");
         };
         return true;
     }
-    warn("Not increasing stack: requested vaddr is outside of stack range.");
+    warn("Not extending stack: address %#x isn't at the end of the stack.",
+        vaddr);
     return false;
 }
 
diff --git a/src/sim/process.hh b/src/sim/process.hh
index 94f6d1800..d48b1b463 100644
--- a/src/sim/process.hh
+++ b/src/sim/process.hh
@@ -212,9 +212,9 @@ class Process : public SimObject
 
     virtual void syscall(int64_t callnum, ThreadContext *tc) = 0;
 
-    // check if the this addr is on the next available page and allocate it
-    // if it's not we'll panic
-    bool checkAndAllocNextPage(Addr vaddr);
+    /// Attempt to fix up a fault at vaddr by allocating a page on the stack.
+    /// @return Whether the fault has been fixed.
+    bool fixupStackFault(Addr vaddr);
 
     void serialize(std::ostream &os);
     void unserialize(Checkpoint *cp, const std::string &section);
-- 
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