Kernel - Change virtual memory API to use void* for virtual addresses

[tpg/acess2.git] / KernelLand / Kernel / arch / x86 / mm_phys.c

diff --git a/KernelLand/Kernel/arch/x86/mm_phys.c b/KernelLand/Kernel/arch/x86/mm_phys.c
index eb422c9..cd5a33d 100644 (file)
--- a/KernelLand/Kernel/arch/x86/mm_phys.c
+++ b/KernelLand/Kernel/arch/x86/mm_phys.c
@@ -391,20 +391,36 @@ void MM_RefPhys(tPAddr PAddr)
        {
                if( MM_GetPhysAddr( &gaPageReferences[PAddr] ) == 0 )
                {
-                        int    i, base;
-                       tVAddr  addr = ((tVAddr)&gaPageReferences[PAddr]) & ~0xFFF;
-//                     Log_Debug("PMem", "MM_RefPhys: Allocating info for %X", PAddr);
+                       Uint base = PAddr & ~(1024-1);
                        Mutex_Release( &glPhysAlloc );
-                       if( MM_Allocate( addr ) == 0 ) {
+                       // No infinite recursion, AllocPhys doesn't need the reference array
+                       // TODO: Race condition? (racy on populating)
+                       if( MM_Allocate( &gaPageReferences[base] ) == 0 )
+                       {
                                Log_KernelPanic("PMem",
                                        "MM_RefPhys: Out of physical memory allocating info for %X",
                                        PAddr*PAGE_SIZE
                                        );
+                               for(;;);
                        }
                        Mutex_Acquire( &glPhysAlloc );
+                       // TODO: Solve race condition. (see below)
+                       // [1] See unallocated
+                       //     Release lock
+                       // [2] Acquire lock
+                       //     See unallocated
+                       //     Release lock
+                       //     Allocate
+                       // [1] Allocate
+                       //     Acquire lock
+                       //     Populate
+                       //     Release lock
+                       // [2] Acquire lock
+                       //     Populate (clobbering)
                        
-                       base = PAddr & ~(1024-1);
-                       for( i = 0; i < 1024; i ++ ) {
+                       // Fill references from allocated bitmap
+                       for( int i = 0; i < 1024; i ++ )
+                       {
                                gaPageReferences[base + i] = (gaPageBitmap[(base+i)/32] & (1 << (base+i)%32)) ? 1 : 0;
                        }
                }
@@ -494,22 +510,19 @@ int MM_GetRefCount(tPAddr PAddr)
 
 int MM_SetPageNode(tPAddr PAddr, void *Node)
 {
-       tVAddr  block_addr;
-       
        if( MM_GetRefCount(PAddr) == 0 )        return 1;
         
        PAddr /= PAGE_SIZE;
 
-       block_addr = (tVAddr) &gaPageNodes[PAddr];
-       block_addr &= ~(PAGE_SIZE-1);
+       void *page_ptr = (void*)( (tVAddr)&gaPageNodes[PAddr] & ~(PAGE_SIZE-1) );
        
-       if( !MM_GetPhysAddr( (void*)block_addr ) )
+       if( !MM_GetPhysAddr( page_ptr ) )
        {
-               if( !MM_Allocate( block_addr ) ) {
+               if( !MM_Allocate( page_ptr ) ) {
                        Log_Warning("PMem", "Unable to allocate Node page");
                        return -1;
                }
-               memset( (void*)block_addr, 0, PAGE_SIZE );
+               memset( page_ptr, 0, PAGE_SIZE );
        }
 
        gaPageNodes[PAddr] = Node;