allow sbrk(-x) to de-allocate user memory

1 files changed, 1 insertions, 0 deletions

diff --git a/defs.h b/defs.h
index b691099..a051522 100644
--- a/defs.h
+++ b/defs.h
@@ -159,6 +159,7 @@ void            vminit(void);
 pde_t*          setupkvm(void);
 char*           uva2ka(pde_t*, char*);
 int             allocuvm(pde_t*, char*, uint);
+int             deallocuvm(pde_t *pgdir, char *addr, uint sz);
 void            freevm(pde_t*);
 void            inituvm(pde_t*, char*, char*, uint);
 int             loaduvm(pde_t*, char*, struct inode *ip, uint, uint);