Kernel/armv7 - Implementing COW

[tpg/acess2.git] / Kernel / arch / armv7 / mm_virt.c

diff --git a/Kernel/arch/armv7/mm_virt.c b/Kernel/arch/armv7/mm_virt.c
index 2c0a2bd..8689e09 100644 (file)
--- a/Kernel/arch/armv7/mm_virt.c
+++ b/Kernel/arch/armv7/mm_virt.c
@@ -52,6 +52,7 @@ tPAddr        MM_Clone(void);
 tVAddr MM_NewKStack(int bGlobal);
 void   MM_int_DumpTableEnt(tVAddr Start, size_t Len, tMM_PageInfo *Info);
 //void MM_DumpTables(tVAddr Start, tVAddr End);
+void   MM_PageFault(Uint32 PC, Uint32 Addr, Uint32 DFSR, int bPrefetch);
 
 // === GLOBALS ===
 tPAddr giMM_ZeroPage;
@@ -118,11 +119,9 @@ int MM_int_AllocateCoarse(tVAddr VAddr, int Domain)
        desc[3] = desc[0] + 0xC00;
 
        if( VAddr < 0x80000000 ) {
-//             Log("USRFRACTAL(%p) = %p", VAddr, &USRFRACTAL(VAddr));
                USRFRACTAL(VAddr) = paddr | 0x13;
        }
        else {
-//             Log("FRACTAL(%p) = %p", VAddr, &FRACTAL(table1, VAddr));
                FRACTAL(table1, VAddr) = paddr | 0x13;
        }
 
@@ -168,7 +167,7 @@ int MM_int_SetPageInfo(tVAddr VAddr, tMM_PageInfo *pi)
 
                        *desc = (pi->PhysAddr & 0xFFFFF000) | 2;
                        if(!pi->bExecutable)    *desc |= 1;     // XN
-                       if(!pi->bGlobal)        *desc |= 1 << 11;       // NG
+                       if(!pi->bGlobal)        *desc |= 1 << 11;       // nG
                        if( pi->bShared)        *desc |= 1 << 10;       // S
                        *desc |= (pi->AP & 3) << 4;     // AP
                        *desc |= ((pi->AP >> 2) & 1) << 9;      // APX
@@ -933,3 +932,47 @@ void MM_DumpTables(tVAddr Start, tVAddr End)
        Debug("Done");
 }
 
+// NOTE: Runs in abort context, not much differe, just a smaller stack
+void MM_PageFault(Uint32 PC, Uint32 Addr, Uint32 DFSR, int bPrefetch)
+{
+        int    rv;
+       tMM_PageInfo    pi;
+       
+       rv = MM_int_GetPageInfo(Addr, &pi);
+       
+       // Check for COW
+       if( rv == 0 &&  pi.AP == AP_RO_BOTH )
+       {
+               Log_Notice("MMVirt", "COW %p caused by %p", Addr, PC);
+               pi.AP = AP_RW_BOTH;
+               if( MM_GetRefCount(pi.PhysAddr) > 1 )
+               {
+                       // Duplicate the page
+                       tPAddr  newpage;
+                       void    *dst, *src;
+                       
+                       newpage = MM_AllocPhys();
+                       if(!newpage) {
+                               Log_Error("MMVirt", "Unable to allocate new page for COW");
+                               for(;;);
+                       }
+                       dst = (void*)MM_MapTemp(newpage);
+                       src = (void*)(Addr & ~(PAGE_SIZE-1));
+                       memcpy( dst, src, PAGE_SIZE );
+                       MM_FreeTemp( (tVAddr)dst );
+                       
+                       pi.PhysAddr = newpage;
+               }
+               // Unset COW
+               pi.AP = AP_RW_BOTH;
+               MM_int_SetPageInfo(Addr, &pi);
+               return ;
+       }
+       
+
+       Log_Error("MMVirt", "Code at %p accessed %p (DFSR = 0x%x)%s", PC, Addr, DFSR,
+               (bPrefetch ? " - Prefetch" : "")
+               );
+       for(;;);
+}
+