diff --git a/unix/internal/mkmerge/mkmerge.go b/unix/internal/mkmerge/mkmerge.go
index 3dda84dc..bb746269 100644
--- a/unix/internal/mkmerge/mkmerge.go
+++ b/unix/internal/mkmerge/mkmerge.go
@@ -32,7 +32,6 @@ import (
 	"go/parser"
 	"go/token"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"path"
@@ -433,7 +432,7 @@ func merge(mergedFile string, archFiles ...string) error {
 	// Read architecture files
 	var inSrc []srcFile
 	for _, file := range archFiles {
-		src, err := ioutil.ReadFile(file)
+		src, err := os.ReadFile(file)
 		if err != nil {
 			return fmt.Errorf("cannot read archfile %s: %w", file, err)
 		}
@@ -485,7 +484,7 @@ func merge(mergedFile string, archFiles ...string) error {
 		if err != nil {
 			return err
 		}
-		err = ioutil.WriteFile(inFile.name, src, 0644)
+		err = os.WriteFile(inFile.name, src, 0644)
 		if err != nil {
 			return err
 		}
diff --git a/unix/linux/mkall.go b/unix/linux/mkall.go
index 5bbc5ca4..e032013a 100644
--- a/unix/linux/mkall.go
+++ b/unix/linux/mkall.go
@@ -24,7 +24,6 @@ import (
 	"fmt"
 	"go/build/constraint"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -810,7 +809,7 @@ func generatePtraceRegSet(arch string) error {
 // ptraceDef returns the definition of PtraceRegs for arch.
 func ptraceDef(arch string) (string, error) {
 	filename := fmt.Sprintf("ztypes_linux_%s.go", arch)
-	data, err := ioutil.ReadFile(filename)
+	data, err := os.ReadFile(filename)
 	if err != nil {
 		return "", fmt.Errorf("reading %s: %v", filename, err)
 	}
diff --git a/unix/mkasm.go b/unix/mkasm.go
index 8c9d27d4..ade20808 100644
--- a/unix/mkasm.go
+++ b/unix/mkasm.go
@@ -12,7 +12,6 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"sort"
@@ -35,7 +34,7 @@ func generateASMFile(goos, arch string, inFileNames []string, outFileName string
 	trampolines := map[string]bool{}
 	var orderedTrampolines []string
 	for _, inFileName := range inFileNames {
-		in, err := ioutil.ReadFile(inFileName)
+		in, err := os.ReadFile(inFileName)
 		if err != nil {
 			log.Fatalf("Failed to read file: %v", err)
 		}
@@ -72,7 +71,7 @@ func generateASMFile(goos, arch string, inFileNames []string, outFileName string
 		fmt.Fprintf(&out, "DATA\t·%s_trampoline_addr(SB)/%d, $%s_trampoline<>(SB)\n", fn, ptrSize, fn)
 	}
 
-	if err := ioutil.WriteFile(outFileName, out.Bytes(), 0644); err != nil {
+	if err := os.WriteFile(outFileName, out.Bytes(), 0644); err != nil {
 		log.Fatalf("Failed to write assembly file %q: %v", outFileName, err)
 	}
 
@@ -110,7 +109,7 @@ func writeDarwinTest(trampolines map[string]bool, fileName, arch string) {
 	out.Reset()
 	fmt.Fprintf(&out, darwinTestTemplate, strings.Join(os.Args[1:], " "), arch, lines)
 
-	if err := ioutil.WriteFile(fileName, out.Bytes(), 0644); err != nil {
+	if err := os.WriteFile(fileName, out.Bytes(), 0644); err != nil {
 		log.Fatalf("Failed to write test file %q: %v", fileName, err)
 	}
 }
diff --git a/unix/mkpost.go b/unix/mkpost.go
index 7de7179e..928e2765 100644
--- a/unix/mkpost.go
+++ b/unix/mkpost.go
@@ -16,7 +16,7 @@ import (
 	"bytes"
 	"fmt"
 	"go/format"
-	"io/ioutil"
+	"io"
 	"log"
 	"os"
 	"regexp"
@@ -41,7 +41,7 @@ func main() {
 		}
 	}
 
-	b, err := ioutil.ReadAll(os.Stdin)
+	b, err := io.ReadAll(os.Stdin)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/unix/mksyscall_aix_ppc64.go b/unix/mksyscall_aix_ppc64.go
index b9c65634..31679e6a 100644
--- a/unix/mksyscall_aix_ppc64.go
+++ b/unix/mksyscall_aix_ppc64.go
@@ -66,7 +66,6 @@ import (
 	"bufio"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"regexp"
 	"strings"
@@ -525,7 +524,7 @@ func main() {
 	}
 
 	// Print zsyscall_aix_ppc64.go
-	err := ioutil.WriteFile("zsyscall_aix_ppc64.go",
+	err := os.WriteFile("zsyscall_aix_ppc64.go",
 		[]byte(fmt.Sprintf(srcTemplate1, cmdLine(), goBuildTags(), plusBuildTags(), pack, imp, textcommon)),
 		0644)
 	if err != nil {
@@ -536,7 +535,7 @@ func main() {
 	// Print zsyscall_aix_ppc64_gc.go
 	vardecls := "\t" + strings.Join(vars, ",\n\t")
 	vardecls += " syscallFunc"
-	err = ioutil.WriteFile("zsyscall_aix_ppc64_gc.go",
+	err = os.WriteFile("zsyscall_aix_ppc64_gc.go",
 		[]byte(fmt.Sprintf(srcTemplate2, cmdLine(), goBuildTags(), plusBuildTags(), pack, imp, dynimports, linknames, vardecls, textgc)),
 		0644)
 	if err != nil {
@@ -545,7 +544,7 @@ func main() {
 	}
 
 	// Print zsyscall_aix_ppc64_gccgo.go
-	err = ioutil.WriteFile("zsyscall_aix_ppc64_gccgo.go",
+	err = os.WriteFile("zsyscall_aix_ppc64_gccgo.go",
 		[]byte(fmt.Sprintf(srcTemplate3, cmdLine(), goBuildTags(), plusBuildTags(), pack, cExtern, imp, textgccgo)),
 		0644)
 	if err != nil {
diff --git a/unix/mksysnum.go b/unix/mksysnum.go
index 1d6e2051..27368041 100644
--- a/unix/mksysnum.go
+++ b/unix/mksysnum.go
@@ -14,7 +14,6 @@ import (
 	"bufio"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"regexp"
@@ -67,7 +66,7 @@ func fetchFile(URL string) io.Reader {
 	resp, err := http.Get(URL)
 	checkErr(err)
 	defer resp.Body.Close()
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	checkErr(err)
 	return strings.NewReader(string(body))
 }