diff --git a/aya/src/maps/perf/perf_buffer.rs b/aya/src/maps/perf/perf_buffer.rs
index 19813557..677f874d 100644
--- a/aya/src/maps/perf/perf_buffer.rs
+++ b/aya/src/maps/perf/perf_buffer.rs
@@ -7,7 +7,7 @@ use std::{
 };
 
 use bytes::BytesMut;
-use libc::{c_int, close, munmap, MAP_FAILED, MAP_SHARED, PROT_READ, PROT_WRITE};
+use libc::{close, munmap, MAP_FAILED, MAP_SHARED, PROT_READ, PROT_WRITE};
 use thiserror::Error;
 
 use crate::{
@@ -15,7 +15,7 @@ use crate::{
         perf_event_header, perf_event_mmap_page,
         perf_event_type::{PERF_RECORD_LOST, PERF_RECORD_SAMPLE},
     },
-    sys::{perf_event_ioctl, perf_event_open_bpf},
+    sys::{mmap, perf_event_ioctl, perf_event_open_bpf},
     PERF_EVENT_IOC_DISABLE, PERF_EVENT_IOC_ENABLE,
 };
 
@@ -278,25 +278,6 @@ impl Drop for PerfBuffer {
     }
 }
 
-#[cfg_attr(test, allow(unused_variables))]
-unsafe fn mmap(
-    addr: *mut c_void,
-    len: usize,
-    prot: c_int,
-    flags: c_int,
-    fd: i32,
-    offset: libc::off_t,
-) -> *mut c_void {
-    #[cfg(not(test))]
-    return libc::mmap(addr, len, prot, flags, fd, offset);
-
-    #[cfg(test)]
-    use crate::sys::TEST_MMAP_RET;
-
-    #[cfg(test)]
-    TEST_MMAP_RET.with(|ret| *ret.borrow())
-}
-
 #[derive(Debug)]
 #[repr(C)]
 struct Sample {
diff --git a/aya/src/sys/mod.rs b/aya/src/sys/mod.rs
index 448e7fee..54cb021b 100644
--- a/aya/src/sys/mod.rs
+++ b/aya/src/sys/mod.rs
@@ -7,7 +7,7 @@ mod fake;
 
 use std::{io, mem};
 
-use libc::{c_int, c_long, pid_t, SYS_bpf, SYS_perf_event_open};
+use libc::{c_int, c_long, c_void, pid_t, SYS_bpf, SYS_perf_event_open};
 
 pub(crate) use bpf::*;
 #[cfg(test)]
@@ -64,3 +64,19 @@ fn syscall(call: Syscall) -> SysResult<c_long> {
         ret => Err((ret, io::Error::last_os_error())),
     }
 }
+
+#[cfg_attr(test, allow(unused_variables))]
+pub(crate) unsafe fn mmap(
+    addr: *mut c_void,
+    len: usize,
+    prot: c_int,
+    flags: c_int,
+    fd: i32,
+    offset: libc::off_t,
+) -> *mut c_void {
+    #[cfg(not(test))]
+    return libc::mmap(addr, len, prot, flags, fd, offset);
+
+    #[cfg(test)]
+    TEST_MMAP_RET.with(|ret| *ret.borrow())
+}