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.

diff --git a/src/arch/alpha/faults.cc b/src/arch/alpha/faults.cc
index b6a0d965e562d4346df60804edbaabd53fda50b7..c66c6f8abf58641560ee04c1c6773d6b431f4366 100644 (file)
--- 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 814a33bd3d2a9dc670274af0886b5474db3328d9..01d57e627b0d4eafe9ce9f7b2ce58486b7d16f3d 100644 (file)
--- 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 9ba20f8d7aa39c99487dc1a78a6148d3817d4251..9d02a00c77e03bc867622d6d0dfb8961881cc342 100644 (file)
--- 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);

diff --git a/src/mem/translating_port.cc b/src/mem/translating_port.cc
index 210f9beb3112414c8b5209c3813e064cf0a157b4..80c68c6bdbf12adc74fa55875372b6b5831aeb76 100644 (file)
--- a/src/mem/translating_port.cc
+++ b/src/mem/translating_port.cc
@@ -90,7 +90,7 @@ TranslatingPort::tryWriteBlob(Addr addr, uint8_t *p, int size)
                                  VMPageSize);
             } else if (allocating == NextPage) {
                 // check if we've accessed the next page on the stack
-                if (!process->checkAndAllocNextPage(gen.addr()))
+                if (!process->fixupStackFault(gen.addr()))
                     panic("Page table fault when accessing virtual address %#x "
                             "during functional write\n", gen.addr());
             } else {

diff --git a/src/sim/faults.cc b/src/sim/faults.cc
index 8e9b8e09419ac44fd5e2a62b3f37fa2f9a8fff9b..3f1369bccd261341bcde6593342597c56ab2192c 100644 (file)
--- 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 bec33c70b9e937a748f9883899b9b72add57635d..62b9b7002564bb868c1cd3067f655fbe8958407e 100644 (file)
--- 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 94f6d1800fa69cfd09b636092ceb0a55c43ff70e..d48b1b463aeec2c2736620acd0d6b86675cee2db 100644 (file)
--- 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);