diff --git a/src/shims/unix/foreign_items.rs b/src/shims/unix/foreign_items.rs
index d155623eb7..bace31fe02 100644
--- a/src/shims/unix/foreign_items.rs
+++ b/src/shims/unix/foreign_items.rs
@@ -163,9 +163,24 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             "ftruncate64" => {
                 let [fd, length] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let fd = this.read_scalar(fd)?.to_i32()?;
+                let length = this.read_scalar(length)?.to_i64()?;
                 let result = this.ftruncate64(fd, length)?;
                 this.write_scalar(result, dest)?;
             }
+            "ftruncate" => {
+                let [fd, length] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let fd = this.read_scalar(fd)?.to_i32()?;
+                let length_type: i64;
+                if this.tcx.sess.target.pointer_width == 64 {
+                    length_type = this.read_scalar(length)?.to_i64()?;
+                } else {
+                    length_type = this.read_scalar(length)?.to_i32()? as i64;
+                }
+                let result = this.ftruncate64(fd, length_type)?;
+                this.write_scalar(result, dest)?;
+            }
             "fsync" => {
                 let [fd] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let result = this.fsync(fd)?;
diff --git a/src/shims/unix/freebsd/foreign_items.rs b/src/shims/unix/freebsd/foreign_items.rs
index 41d395dd0c..7c843e106e 100644
--- a/src/shims/unix/freebsd/foreign_items.rs
+++ b/src/shims/unix/freebsd/foreign_items.rs
@@ -3,7 +3,6 @@ use rustc_target::spec::abi::Abi;
 
 use crate::*;
 use shims::foreign_items::EmulateForeignItemResult;
-use shims::unix::fs::EvalContextExt as _;
 use shims::unix::thread::EvalContextExt as _;
 
 pub fn is_dyn_sym(_name: &str) -> bool {
@@ -63,15 +62,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                 this.gen_random(ptr, len)?;
                 this.write_scalar(Scalar::from_target_usize(len, this), dest)?;
             }
-            "ftruncate" => {
-                if this.tcx.sess.target.pointer_width == 32 {
-                    throw_unsup_format!("`ftruncate` is not supported on 32 bits");
-                }
-                let [fd, length] =
-                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
-                let result = this.ftruncate64(fd, length)?;
-                this.write_scalar(result, dest)?;
-            }
 
             // errno
             "__error" => {
diff --git a/src/shims/unix/fs.rs b/src/shims/unix/fs.rs
index 062623a7f6..721fa16123 100644
--- a/src/shims/unix/fs.rs
+++ b/src/shims/unix/fs.rs
@@ -1504,16 +1504,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         }
     }
 
-    fn ftruncate64(
-        &mut self,
-        fd_op: &OpTy<'tcx, Provenance>,
-        length_op: &OpTy<'tcx, Provenance>,
-    ) -> InterpResult<'tcx, Scalar<Provenance>> {
+    fn ftruncate64(&mut self, fd: i32, length: i64) -> InterpResult<'tcx, Scalar<Provenance>> {
         let this = self.eval_context_mut();
 
-        let fd = this.read_scalar(fd_op)?.to_i32()?;
-        let length = this.read_scalar(length_op)?.to_i64()?;
-
         // Reject if isolation is enabled.
         if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
             this.reject_in_isolation("`ftruncate64`", reject_with)?;
diff --git a/src/shims/unix/macos/foreign_items.rs b/src/shims/unix/macos/foreign_items.rs
index e8f35e7ba5..07e19cadd6 100644
--- a/src/shims/unix/macos/foreign_items.rs
+++ b/src/shims/unix/macos/foreign_items.rs
@@ -72,13 +72,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                 let result = this.lseek64(fd, offset, whence)?;
                 this.write_scalar(result, dest)?;
             }
-            "ftruncate" => {
-                let [fd, length] =
-                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
-                // macOS is 64bit-only, so this is ftruncate64
-                let result = this.ftruncate64(fd, length)?;
-                this.write_scalar(result, dest)?;
-            }
             "realpath$DARWIN_EXTSN" => {
                 let [path, resolved_path] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
diff --git a/tests/pass-dep/shims/libc-misc.rs b/tests/pass-dep/shims/libc-misc.rs
index 635a1215b4..6a8430f356 100644
--- a/tests/pass-dep/shims/libc-misc.rs
+++ b/tests/pass-dep/shims/libc-misc.rs
@@ -237,7 +237,6 @@ fn test_isatty() {
     }
 }
 
-#[cfg(not(all(target_os = "freebsd", pointer_width = "32")))]
 fn test_posix_mkstemp() {
     use std::ffi::CString;
     use std::ffi::OsStr;
@@ -416,7 +415,6 @@ fn main() {
 
     test_isatty();
 
-    //#[cfg(not(target_os = "freebsd"))] // FIXME we should support this on FreeBSD as well
     test_clocks();
 
     test_dlsym();