Redesign userspace memory management

kernel/amd64/proc.h

@@ -4,15 +4,16 @@
 #include <amd64/intr.h>
 #include <libk/std.h>
 
-/// Top of userspace process' stack
+/* Top of userspace process' stack */
 #define PROC_USTACK_TOP 0x00007FFFFFFFF000ULL
-/// Size of userspace process' stack
+/* Size of userspace process' stack */
 #define USTACK_SIZE (256 * PAGE_SIZE)
+/* proc_map () base address */
+#define PROC_MAP_BASE 0x0000700000000000
 
-/// Platform-dependent process data
+/* Platform-dependent process data */
 struct proc_platformdata {
   struct saved_regs regs;
-  uintptr_t user_stack;
   uintptr_t kernel_stack;
   uint64_t gs_base;
 };