1 files changed, 78 insertions, 0 deletions
diff --git a/src/runtime/os_linux32.go b/src/runtime/os_linux32.go
new file mode 100644
index 0000000000..16de6fb350
--- /dev/null
+++ b/src/runtime/os_linux32.go
@@ -0,0 +1,78 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build linux && (386 || arm || mips || mipsle || (gccgo && (ppc || s390)))
+
+package runtime
+
+import (
+	"internal/runtime/atomic"
+	"unsafe"
+)
+
+//go:noescape
+func futex_time32(addr unsafe.Pointer, op int32, val uint32, ts *timespec32, addr2 unsafe.Pointer, val3 uint32) int32
+
+//go:noescape
+func futex_time64(addr unsafe.Pointer, op int32, val uint32, ts *timespec, addr2 unsafe.Pointer, val3 uint32) int32
+
+var isFutexTime32bitOnly atomic.Bool
+
+//go:nosplit
+func futex(addr unsafe.Pointer, op int32, val uint32, ts *timespec, addr2 unsafe.Pointer, val3 uint32) int32 {
+	if !isFutexTime32bitOnly.Load() {
+		ret := futex_time64(addr, op, val, ts, addr2, val3)
+		// futex_time64 is only supported on Linux 5.0+
+		if ret != -_ENOSYS {
+			return ret
+		}
+		isFutexTime32bitOnly.Store(true)
+	}
+	// Downgrade ts.
+	var ts32 timespec32
+	var pts32 *timespec32
+	if ts != nil {
+		ts32.setNsec(ts.tv_sec*1e9 + ts.tv_nsec)
+		pts32 = &ts32
+	}
+	return futex_time32(addr, op, val, pts32, addr2, val3)
+}
+
+//go:noescape
+func timer_settime32(timerid int32, flags int32, new, old *itimerspec32) int32
+
+//go:noescape
+func timer_settime64(timerid int32, flags int32, new, old *itimerspec) int32
+
+var isSetTime32bitOnly atomic.Bool
+
+//go:nosplit
+func timer_settime(timerid int32, flags int32, new, old *itimerspec) int32 {
+	if !isSetTime32bitOnly.Load() {
+		ret := timer_settime64(timerid, flags, new, old)
+		// timer_settime64 is only supported on Linux 5.0+
+		if ret != -_ENOSYS {
+			return ret
+		}
+		isSetTime32bitOnly.Store(true)
+	}
+
+	var newts, oldts itimerspec32
+	var new32, old32 *itimerspec32
+
+	if new != nil {
+		newts.it_interval.setNsec(new.it_interval.tv_sec*1e9 + new.it_interval.tv_nsec)
+		newts.it_value.setNsec(new.it_value.tv_sec*1e9 + new.it_value.tv_nsec)
+		new32 = &newts
+	}
+
+	if old != nil {
+		oldts.it_interval.setNsec(old.it_interval.tv_sec*1e9 + old.it_interval.tv_nsec)
+		oldts.it_value.setNsec(old.it_value.tv_sec*1e9 + old.it_value.tv_nsec)
+		old32 = &oldts
+	}
+
+	// Fall back to 32-bit timer
+	return timer_settime32(timerid, flags, new32, old32)
+}