diff --git a/libc/SYSCALLS.TXT b/libc/SYSCALLS.TXT
index 39ff37d..d9ede2f 100644
--- a/libc/SYSCALLS.TXT
+++ b/libc/SYSCALLS.TXT
@@ -101,7 +101,7 @@
 void*       mremap(void*, size_t, size_t, unsigned long)  all
 int         msync(const void*, size_t, int)    all
 int         mprotect(const void*, size_t, int)  all
-int         madvise(const void*, size_t, int)  all
+int         madvise(void*, size_t, int)  all
 int         mlock(const void* addr, size_t len)    all
 int         munlock(const void* addr, size_t len)   all
 int         mlockall(int flags)   all
diff --git a/libc/include/sys/mman.h b/libc/include/sys/mman.h
index 5a8c985..09bf0d9 100644
--- a/libc/include/sys/mman.h
+++ b/libc/include/sys/mman.h
@@ -54,7 +54,7 @@
 extern int munlockall(void);
 extern int mlock(const void*, size_t);
 extern int munlock(const void*, size_t);
-extern int madvise(const void*, size_t, int);
+extern int madvise(void*, size_t, int);
 
 extern int mlock(const void*, size_t);
 extern int munlock(const void*, size_t);