cow

kernel/interrupt/handlers.cc

@@ -9,6 +9,8 @@
 #include "../device/ps2controller.h"
 #include "./epilogues.h"
 #include "./guard.h"
+#include "../memory/pagetable.h"
+#include "../memory/pageframealloc.h"
 
 static void printContext(const InterruptContext *context) {
 	DBG << "ip: " << hex << context->cs << ':' << context->ip
@@ -49,14 +51,39 @@ static void printContext(const InterruptContext *context) {
 
 #include "syscall/skeleton.h"
 [[gnu::interrupt]] static void handle_page_fault(InterruptContext *context,
-												 uint64_t error) {
-	DBG << "Page fault encountered at linear address " << hex
-		<< Core::CR<2>::read() << endl
-		<< PageFaultError(error) << endl;
-	printContext(context);
+    uint64_t error) {
+  DBG << "Page fault encountered at linear address " << hex
+    << Core::CR<2>::read() << endl
+    << PageFaultError(error) << endl;
+  four_lvl_paging_t* paging_tree  =   Guard::enter().vault().scheduler.active()->paging_tree ;
+  asm volatile("mov %%cr3, %0" : "=r"(paging_tree));
 
-    Syscall::Skeleton::exit(Guard::enter().vault());
-    //kernelpanic("Page fault!");
+  uintptr_t virt = 0;
+  asm volatile("mov %%cr2, %0" : "=r"(virt));
+  if (PageFaultError(error).present && PageFaultError(error).write) {
+    uintptr_t pf =isMapped(virt, paging_tree);
+    uint64_t pf_number = uint64_t (pf >> 12 );
+
+    if(PageFrameAllocator::PageFrames[pf_number].ref_count==1){
+      setMapping(virt,  (void*) pf , paging_tree, 1);
+
+    }else{
+
+      uintptr_t page = (uintptr_t) PageFrameAllocator::alloc(false);
+      //Syscall::Skeleton::map(page, 4096);
+      setMapping(virt,  (void*) page , paging_tree, 1);
+
+      memcpy( (void*)page, (void*)virt, 4096);
+      Syscall::Skeleton::invlpg(virt);
+    }
+
+
+
+
+  }
+
+Syscall::Skeleton::exit(Guard::enter().vault());
+//kernelpanic("Page fault!");
 }
 
 /*! \brief Assembly interrupt handler for the keyboard.