Massive changes to jump to userspace

1 files changed, 52 insertions, 0 deletions

diff --git a/arch/riscv/kernel/vmem.c b/arch/riscv/kernel/vmem.c
new file mode 100644
index 0000000..ffe8731
--- /dev/null
+++ b/arch/riscv/kernel/vmem.c
@@ -0,0 +1,52 @@
+#include <apos/string.h>
+#include <apos/pmem.h>
+#include <apos/vmem.h>
+#include <apos/mem.h>
+#include <apos/debug.h>
+#include <pages.h>
+
+#define pte_ppn(pte) (((pm_t)(pte)) >> 10)
+#define pte_flags(pte) (((pm_t)(pte)) & 0xff)
+#define to_pte(p, f) ((pm_to_pnum(p) << 10) + (f))
+#define pte_addr(pte) (pnum_to_paddr(pte_ppn(pte)))
+#define vm_to_index(a, o) (pm_to_index(a, o))
+
+void map_vmem(struct vm_branch_t *branch,
+		pm_t paddr, vm_t vaddr, uint8_t flags, enum mm_order_t order)
+{
+	enum mm_order_t top = __mm_max_order;
+	while (top != order) {
+		size_t idx = vm_to_index(vaddr, top);
+
+		if (!branch->leaf[idx]) {
+			pm_t new_leaf = alloc_page(MM_KPAGE, 0);
+			branch->leaf[idx] =
+				(struct vm_branch_t *)to_pte(new_leaf, VM_V);
+
+			void *leaf_ptr = (void *)new_leaf;
+			memset(leaf_ptr, 0, sizeof(struct vm_branch_t));
+		}
+
+		pm_t pte = (pm_t)branch->leaf[idx];
+		pm_t branch_pptr = (pm_t)pte_addr(pte);
+		branch = (struct vm_branch_t *)branch_pptr;
+		top--;
+	}
+
+	size_t idx = vm_to_index(vaddr, top);
+	branch->leaf[idx] = (struct vm_branch_t *)to_pte(paddr, flags);
+}
+
+void unmap_vmem(struct vm_branch_t *branch, vm_t vaddr, enum mm_order_t order)
+{
+	while (order) {
+		size_t idx = pm_to_index(vaddr, order);
+		branch = (struct vm_branch_t *)pte_addr(branch->leaf[idx]);
+	}
+
+	size_t idx = pm_to_index(vaddr, order);
+	if (branch->leaf[idx])
+		free_page(order, pte_addr(branch->leaf[idx]));
+
+	branch->leaf[idx] = 0;
+}