syscall_emul: implement MAP_FIXED option to mmap()

2 files changed, 28 insertions, 8 deletions

diff --git a/src/mem/page_table.cc b/src/mem/page_table.cc
index a94d92480..745872319 100644
--- a/src/mem/page_table.cc
+++ b/src/mem/page_table.cc
@@ -67,7 +67,7 @@ PageTable::~PageTable()
 }
 
 void
-PageTable::allocate(Addr vaddr, int64_t size)
+PageTable::allocate(Addr vaddr, int64_t size, bool clobber)
 {
     // starting address must be page aligned
     assert(pageOffset(vaddr) == 0);
@@ -75,16 +75,13 @@ PageTable::allocate(Addr vaddr, int64_t size)
     DPRINTF(MMU, "Allocating Page: %#x-%#x\n", vaddr, vaddr+ size);
 
     for (; size > 0; size -= pageSize, vaddr += pageSize) {
-        PTableItr iter = pTable.find(vaddr);
-
-        if (iter != pTable.end()) {
+        if (!clobber && (pTable.find(vaddr) != pTable.end())) {
             // already mapped
-            fatal("PageTable::allocate: address 0x%x already mapped",
-                    vaddr);
+            fatal("PageTable::allocate: address 0x%x already mapped", vaddr);
         }
 
         pTable[vaddr] = TheISA::TlbEntry(process->M5_pid, vaddr,
-                process->system->new_page());
+                                         process->system->new_page());
         updateCache(vaddr, pTable[vaddr]);
     }
 }
@@ -128,6 +125,21 @@ PageTable::deallocate(Addr vaddr, int64_t size)
 }
 
 bool
+PageTable::isUnmapped(Addr vaddr, int64_t size)
+{
+    // starting address must be page aligned
+    assert(pageOffset(vaddr) == 0);
+
+    for (; size > 0; size -= pageSize, vaddr += pageSize) {
+        if (pTable.find(vaddr) != pTable.end()) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+bool
 PageTable::lookup(Addr vaddr, TheISA::TlbEntry &entry)
 {
     Addr page_addr = pageAlign(vaddr);
diff --git a/src/mem/page_table.hh b/src/mem/page_table.hh
index 61da5f322..d60f4a433 100644
--- a/src/mem/page_table.hh
+++ b/src/mem/page_table.hh
@@ -79,11 +79,19 @@ class PageTable
     Addr pageAlign(Addr a)  { return (a & ~offsetMask); }
     Addr pageOffset(Addr a) { return (a &  offsetMask); }
 
-    void allocate(Addr vaddr, int64_t size);
+    void allocate(Addr vaddr, int64_t size, bool clobber = false);
     void remap(Addr vaddr, int64_t size, Addr new_vaddr);
     void deallocate(Addr vaddr, int64_t size);
 
     /**
+     * Check if any pages in a region are already allocated
+     * @param vaddr The starting virtual address of the region.
+     * @param size The length of the region.
+     * @return True if no pages in the region are mapped.
+     */
+    bool isUnmapped(Addr vaddr, int64_t size);
+
+    /**
      * Lookup function
      * @param vaddr The virtual address.
      * @return entry The page table entry corresponding to vaddr.