implemented map_region() (more testing needed; will propably replaced by a iterative solution)

arch/x86/mm/page64.c

@@ -283,21 +283,14 @@ size_t virt_to_phys(size_t viraddr)
 size_t map_region(size_t viraddr, size_t phyaddr, uint32_t npages, uint32_t flags)
 {
 	task_t* task = per_core(current_task);
-	page_map_t* pdpt, * pgd, * pgt;
-	uint16_t index_pml4, index_pdpt;
-	uint16_t index_pgd, index_pgt;
 	size_t i, ret;
 
 	if (BUILTIN_EXPECT(!task || !task->page_map, 0))
 		return 0;
 
-	if (flags & MAP_KERNEL_SPACE)
-		spinlock_lock(&kslock);
-	else 
-		spinlock_irqsave_lock(&task->page_lock);
-
 	if (!viraddr) {
-		viraddr = vm_alloc(npages, flags);
+		kputs("map_region: deprecated vma_alloc() call from within map_region\n");
+		viraddr = vma_alloc(npages*PAGE_SIZE, VMA_HEAP);
 		if (BUILTIN_EXPECT(!viraddr, 0)) {
 			kputs("map_region: found no valid virtual address\n");
 			ret = 0;
@@ -305,59 +298,40 @@ size_t map_region(size_t viraddr, size_t phyaddr, uint32_t npages, uint32_t flag
 		}
 	}
 
+	// correct alignment
+	phyaddr &= PAGE_MASK;
+	viraddr &= PAGE_MASK;
 	ret = viraddr;
+
+	if (flags & MAP_KERNEL_SPACE)
+		spinlock_lock(&kslock);
+	else 
+		spinlock_irqsave_lock(&task->page_lock);
+
+	kprintf("map_region: map %u pages from 0x%lx to 0x%lx with flags: 0x%x\n", npages, viraddr, phyaddr, flags);
 	for(i=0; i<npages; i++, viraddr+=PAGE_SIZE, phyaddr+=PAGE_SIZE) {
-		index_pml4 = (viraddr >> 39) & 0x1FF;
+		// page table entry
-		index_pdpt = (viraddr >> 30) & 0x1FF;
+		size_t* pte = (size_t *) (PAGE_PGT|(viraddr >> 9));
-		index_pgd = (viraddr >> 21) & 0x1FF;
-		index_pgt = (viraddr >> 12) & 0x1FF;
 
-		pdpt = (page_map_t*) (task->page_map->entries[index_pml4] & PAGE_MASK);
+		if (*pte && !(flags & MAP_REMAP)) {
-		if (!pgt) {
+			kprintf("map_region: 0x%lx is already mapped\n", viraddr);
-			kputs("map_region: out of memory\n");
-			ret = 0;
-			goto out;
-		}
-
-		pgd = (page_map_t*) (pdpt->entries[index_pdpt] & PAGE_MASK);
-		if (!pgd) {
-			kputs("map_region: out of memory\n");
-			ret = 0;
-			goto out;
-		}
-
-		pgt = (page_map_t*) (pgd->entries[index_pgd] & PAGE_MASK);
-		if (!pgt) {
-			kputs("map_region: out of memory\n");
-			ret = 0;
-			goto out;
-		}
-
-		/* convert physical address to virtual */
-		// Currently, we allocate pages only in kernel space.
-		// => physical address of the page table is identical of the virtual address
-		//if (paging_enabled)
-		//	pgt = (page_map_t*) ((KERNEL_SPACE - 1024*PAGE_SIZE + index*PAGE_SIZE) & PAGE_MASK);
-
-		if (pgt->entries[index_pgt] && !(flags & MAP_REMAP)) {
-			kprintf("0x%x is already mapped\n", viraddr);
 			ret = 0;
 			goto out;
 		}
 
 		if (flags & MAP_USER_SPACE)
-			pgt->entries[index_pgt] = USER_PAGE|(phyaddr & PAGE_MASK);
+			*pte = phyaddr|USER_PAGE;
 		else
-			pgt->entries[index_pgt] = KERN_PAGE|(phyaddr & PAGE_MASK);
+			*pte = phyaddr|KERN_PAGE;
 
 		if (flags & MAP_NO_CACHE)
-			pgt->entries[index_pgt] |= PG_PCD;
+			*pte |= PG_PCD;
 
 		if (flags & MAP_NO_ACCESS)
-			pgt->entries[index_pgt] &= ~PG_PRESENT;
+			*pte &= ~PG_PRESENT;
 
 		if (flags & MAP_WT)
-			pgt->entries[index_pgt] |= PG_PWT;
+			*pte |= PG_PWT;
 
 		if (flags & MAP_USER_SPACE)
 			atomic_int32_inc(&task->user_usage);
@@ -651,10 +625,8 @@ int vm_free(size_t viraddr, uint32_t npages)
 static void pagefault_handler(struct state *s)
 {
 	task_t* task = per_core(current_task);
-	//page_map_t* pgd = task->page_map;
-	//page_map_t* pgt = NULL;
 	size_t viraddr = read_cr2();
-	//size_t phyaddr;
+	size_t phyaddr;
 
 #if 0
 	if ((viraddr >= task->start_heap) && (viraddr <= task->end_heap) && (viraddr > KERNEL_SPACE)) {
@@ -662,7 +634,7 @@ static void pagefault_handler(struct state *s)
 
 		phyaddr = get_page();
 		if (BUILTIN_EXPECT(!phyaddr, 0))
-			goto default_handler;
+			goto oom;
 
 		if (map_region(viraddr, phyaddr, 1, MAP_USER_SPACE) == viraddr) {
 			memset((void*) viraddr, 0x00, PAGE_SIZE);
@@ -672,14 +644,37 @@ static void pagefault_handler(struct state *s)
 		kprintf("Could not map 0x%x at 0x%x\n", phyaddr, viraddr);
 		put_page(phyaddr);
 	}
+	// handle missing paging structures for userspace
+	// all kernel space paging structures have been initialized in entry64.asm
+	else if (viraddr >= PAGE_PGT) {
+		kprintf("map_region: missing paging structure at: 0x%lx (%s)\n", viraddr, map_to_lvlname(viraddr));
+
+		phyaddr = get_page();
+		if (BUILTIN_EXPECT(!phyaddr, 0))
+			goto oom;
+
+		// TODO: initialize with zeros
+		// TODO: check that we are in userspace
+
+		// get pointer to parent page level entry
+		size_t *entry = (size_t *) ((int64_t) viraddr >> 9 & ~0x07);
+
+		// update entry
+		*entry = phyaddr|USER_TABLE;
+
+		return;
+	}
 #endif
 
-//default_handler:
 	kprintf("PAGE FAULT: Task %u got page fault at %p (irq %llu, cs:rip 0x%llx:0x%llx)\n", task->id, viraddr, s->int_no, s->cs, s->rip);
 	kprintf("Register state: rax = 0x%llx, rbx = 0x%llx, rcx = 0x%llx, rdx = 0x%llx, rdi = 0x%llx, rsi = 0x%llx, rbp = 0x%llx, rsp = 0x%llx\n", 
 		s->rax, s->rbx, s->rcx, s->rdx, s->rdi, s->rsi, s->rbp, s->rsp);
 
-while(1);
+	irq_enable();
+	abort();
+
+oom:
+	kputs("map_region: out of memory\n");
 	irq_enable();
 	abort();
 }