If the pgdir in debug_print_pgdir is not set, assume rcr3()

This is a convenience when using the monitor

Signed-off-by: Ron Minnich <rminnich@gmail.com>

kern/arch/x86/pmap64.c

diff --git a/kern/arch/x86/pmap64.c b/kern/arch/x86/pmap64.c
index 2fb1112..5b76771 100644
--- a/kern/arch/x86/pmap64.c
+++ b/kern/arch/x86/pmap64.c
@@ -600,6 +600,8 @@
 
 void debug_print_pgdir(kpte_t *pgdir)
 {
+	if (! pgdir)
+		pgdir = KADDR(rcr3());
 	printk("Printing the entire page table set for %p, DFS\n", pgdir);
 	/* Need to be careful we avoid VPT/UVPT, o/w we'll recurse */
 	pml_for_each(pgdir, 0, UVPT, print_pte, 0);