x86_64: add pmap_handle_fault to route user-mode page faults to vm-region to resolve

arch/x86_64/pmap.c

@@ -1,9 +1,13 @@
 #include <mango/compiler.h>
+#include <mango/libc/stdio.h>
 #include <mango/memblock.h>
 #include <mango/pmap.h>
 #include <mango/printk.h>
+#include <mango/sched.h>
 #include <mango/status.h>
 #include <mango/types.h>
+#include <mango/vm-object.h>
+#include <mango/vm-region.h>
 #include <mango/vm.h>
 
 /* some helpful datasize constants */
@@ -296,13 +300,73 @@ void pmap_bootstrap(void)
 
 pmap_t pmap_create(void)
 {
-	return 0;
+	pmap_t pmap = alloc_pmap();
+	pmap_t kernel_pmap = get_kernel_pmap();
+
+	struct pml4t *pml4t = vm_phys_to_virt(pmap);
+	struct pml4t *kernel_pml4t = vm_phys_to_virt(kernel_pmap);
+
+	for (unsigned int i = 256; i < 512; i++) {
+		pml4t->p_entries[i] = kernel_pml4t->p_entries[i];
+	}
+
+	return pmap;
 }
 
 void pmap_destroy(pmap_t pmap)
 {
 }
 
+static void log_fault(virt_addr_t fault_addr, enum pmap_fault_flags flags)
+{
+	char flag_str[128] = {0};
+	size_t p = 0;
+
+	if (flags & PMAP_FAULT_PRESENT) {
+		p += snprintf(flag_str + p, sizeof flag_str - p, " PRESENT");
+	} else {
+		p += snprintf(flag_str + p, sizeof flag_str - p, " MISSING");
+	}
+
+	if (flags & PMAP_FAULT_USER) {
+		p += snprintf(flag_str + p, sizeof flag_str - p, " USER");
+	} else {
+		p += snprintf(flag_str + p, sizeof flag_str - p, " SVR");
+	}
+
+	if (flags & PMAP_FAULT_WRITE) {
+		p += snprintf(flag_str + p, sizeof flag_str - p, " WRITE");
+	} else {
+		p += snprintf(flag_str + p, sizeof flag_str - p, " READ");
+	}
+
+	if (flags & PMAP_FAULT_IFETCH) {
+		p += snprintf(flag_str + p, sizeof flag_str - p, " IFETCH");
+	}
+
+	if (flags & PMAP_FAULT_BADCFG) {
+		p += snprintf(flag_str + p, sizeof flag_str - p, " BADCFG");
+	}
+
+	printk("pmap: fault at 0x%llx (%s)", fault_addr, flag_str);
+}
+
+kern_status_t pmap_handle_fault(
+	virt_addr_t fault_addr,
+	enum pmap_fault_flags flags)
+{
+	// log_fault(fault_addr, flags);
+
+	if (flags & PMAP_FAULT_PRESENT) {
+		return KERN_FATAL_ERROR;
+	}
+
+	struct task *task = current_task();
+	struct vm_region *space = task->t_address_space;
+
+	return vm_region_demand_map(space, fault_addr, flags);
+}
+
 kern_status_t pmap_add(
 	pmap_t pmap,
 	virt_addr_t p,