diff --git a/src/call.rs b/src/call.rs
index cf89465..aff381a 100644
--- a/src/call.rs
+++ b/src/call.rs
@@ -230,6 +230,11 @@ pub fn mkns(schemes: &[[usize; 2]]) -> Result<usize> {
     unsafe { syscall2(SYS_MKNS, schemes.as_ptr() as usize, schemes.len()) }
 }
 
+/// Change mapping flags
+pub unsafe fn mprotect(addr: usize, size: usize, flags: usize) -> Result<usize> {
+    syscall3(SYS_MPROTECT, addr, size, flags)
+}
+
 /// Sleep for the time specified in `req`
 pub fn nanosleep(req: &TimeSpec, rem: &mut TimeSpec) -> Result<usize> {
     unsafe { syscall2(SYS_NANOSLEEP, req as *const TimeSpec as usize,
diff --git a/src/number.rs b/src/number.rs
index 4d55d0a..ec9acfa 100644
--- a/src/number.rs
+++ b/src/number.rs
@@ -55,6 +55,7 @@ pub const SYS_GETPPID: usize =  64;
 pub const SYS_GETUID: usize =   199;
 pub const SYS_IOPL: usize =     110;
 pub const SYS_KILL: usize =     37;
+pub const SYS_MPROTECT: usize = 125;
 pub const SYS_MKNS: usize =     984;
 pub const SYS_NANOSLEEP: usize =162;
 pub const SYS_PHYSALLOC: usize =945;