implement munmap

Also add basic errno.h

core/uaddrspace.c

@@ -334,6 +334,7 @@ int uAddrSpaceMmap(struct uAddrSpace *as, uaddr_t *uaddr, size_t size, uint32_t
             return -EPERM;
     }
 
+    size = ALIGN(size, PAGE_SIZE);
     struct uAddrVirtualReg *reg =
         (struct uAddrVirtualReg *)malloc(sizeof(struct uAddrVirtualReg));
     if (!reg)

userspace/libc.c

@@ -743,5 +743,5 @@ int munmap(void *addr, size_t len)
     if (len == 0)
         return -EINVAL;
 
-    return syscall2(SYSCALL_ID_MUNMAP, (unsigned int)&addr, len);
+    return syscall2(SYSCALL_ID_MUNMAP, (unsigned int)addr, len);
 }

userspace/main_user.c

@@ -111,6 +111,7 @@ int func_munmap()
                 return ret;
         }
 
+        printf("unmap done\n");
         listMmap = listMmap->next;
         free(area);