feat(mm): add allocators

src/mm/root.zig

@@ -6,6 +6,7 @@ const std = @import("std");
 pub const page_size = 4096;
 
 pub const init = private.init.init;
+pub const vmem = private.vmem;
 
 // 16 TB of maximum physical memory.
 // This should be fine on consumer hardware for at least a decade :^)
@@ -28,6 +29,8 @@ pub const MapFlags = packed struct {
     cache_disable: bool = false,
 };
 
+pub const Error = error{OutOfMemory, InvalidAddress, InvalidSize};
+
 pub inline fn page_to_pfn(addr: usize) Pfn {
     return @intCast(addr >> 12);
 }