diff --git a/aya/src/maps/bloom_filter.rs b/aya/src/maps/bloom_filter.rs
index dfe4d2cb..4d771441 100644
--- a/aya/src/maps/bloom_filter.rs
+++ b/aya/src/maps/bloom_filter.rs
@@ -91,8 +91,8 @@ mod tests {
         sys::{override_syscall, SysResult, Syscall},
     };
     use assert_matches::assert_matches;
-    use libc::{EFAULT, ENOENT};
-    use std::{ffi::c_long, io};
+    use libc::{c_long, EFAULT, ENOENT};
+    use std::io;
 
     fn new_obj_map() -> obj::Map {
         obj::Map::Legacy(LegacyMap {
diff --git a/aya/src/maps/hash_map/hash_map.rs b/aya/src/maps/hash_map/hash_map.rs
index 9d587b33..f5089a12 100644
--- a/aya/src/maps/hash_map/hash_map.rs
+++ b/aya/src/maps/hash_map/hash_map.rs
@@ -103,10 +103,10 @@ impl<T: Borrow<MapData>, K: Pod, V: Pod> IterableMap<K, V> for HashMap<T, K, V>
 
 #[cfg(test)]
 mod tests {
-    use std::{ffi::c_long, io};
+    use std::io;
 
     use assert_matches::assert_matches;
-    use libc::{EFAULT, ENOENT};
+    use libc::{c_long, EFAULT, ENOENT};
 
     use crate::{
         generated::{
diff --git a/aya/src/maps/lpm_trie.rs b/aya/src/maps/lpm_trie.rs
index d4e1e678..76648560 100644
--- a/aya/src/maps/lpm_trie.rs
+++ b/aya/src/maps/lpm_trie.rs
@@ -208,8 +208,8 @@ mod tests {
         sys::{override_syscall, SysResult, Syscall},
     };
     use assert_matches::assert_matches;
-    use libc::{EFAULT, ENOENT};
-    use std::{ffi::c_long, io, mem, net::Ipv4Addr};
+    use libc::{c_long, EFAULT, ENOENT};
+    use std::{io, mem, net::Ipv4Addr};
 
     fn new_obj_map() -> obj::Map {
         obj::Map::Legacy(LegacyMap {
diff --git a/aya/src/maps/perf/perf_buffer.rs b/aya/src/maps/perf/perf_buffer.rs
index 898dd04b..4dc63d98 100644
--- a/aya/src/maps/perf/perf_buffer.rs
+++ b/aya/src/maps/perf/perf_buffer.rs
@@ -1,5 +1,4 @@
 use std::{
-    ffi::c_void,
     io, mem,
     os::fd::{AsFd, AsRawFd, BorrowedFd, OwnedFd, RawFd},
     ptr, slice,
@@ -7,7 +6,7 @@ use std::{
 };
 
 use bytes::BytesMut;
-use libc::{c_int, munmap, MAP_FAILED, MAP_SHARED, PROT_READ, PROT_WRITE};
+use libc::{c_void, munmap, MAP_FAILED, MAP_SHARED, PROT_READ, PROT_WRITE};
 use thiserror::Error;
 
 use crate::{
@@ -15,7 +14,7 @@ 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, SysResult},
+    sys::{mmap, perf_event_ioctl, perf_event_open_bpf, SysResult},
     PERF_EVENT_IOC_DISABLE, PERF_EVENT_IOC_ENABLE,
 };
 
@@ -282,25 +281,6 @@ 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: BorrowedFd<'_>,
-    offset: libc::off_t,
-) -> *mut c_void {
-    #[cfg(not(test))]
-    return libc::mmap(addr, len, prot, flags, fd.as_raw_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/fake.rs b/aya/src/sys/fake.rs
index df2deece..fba0c144 100644
--- a/aya/src/sys/fake.rs
+++ b/aya/src/sys/fake.rs
@@ -1,6 +1,6 @@
-use std::{cell::RefCell, ffi::c_long, io, ptr};
+use std::{cell::RefCell, io, ptr};
 
-use libc::c_void;
+use libc::{c_long, c_void};
 
 use super::{SysResult, Syscall};
 
diff --git a/aya/src/sys/mod.rs b/aya/src/sys/mod.rs
index 239e68a9..952d3793 100644
--- a/aya/src/sys/mod.rs
+++ b/aya/src/sys/mod.rs
@@ -5,7 +5,7 @@ mod perf_event;
 #[cfg(test)]
 mod fake;
 
-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};
 use std::{
     io, mem,
     os::fd::{AsRawFd as _, BorrowedFd},
@@ -114,3 +114,19 @@ 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: BorrowedFd<'_>,
+    offset: libc::off_t,
+) -> *mut c_void {
+    #[cfg(not(test))]
+    return libc::mmap(addr, len, prot, flags, fd.as_raw_fd(), offset);
+
+    #[cfg(test)]
+    TEST_MMAP_RET.with(|ret| *ret.borrow())
+}
diff --git a/aya/src/sys/perf_event.rs b/aya/src/sys/perf_event.rs
index 1659778a..4b42e529 100644
--- a/aya/src/sys/perf_event.rs
+++ b/aya/src/sys/perf_event.rs
@@ -1,10 +1,10 @@
 use std::{
-    ffi::{c_long, CString, OsStr},
+    ffi::{CString, OsStr},
     io, mem,
     os::fd::{BorrowedFd, FromRawFd as _, OwnedFd},
 };
 
-use libc::{c_int, pid_t};
+use libc::{c_int, c_long, pid_t};
 
 use crate::generated::{
     perf_event_attr,